CEA |   |   |   |   |   |   | webmail : intra - extra |  Accès VPN-SSL | Contact | Français

PhD subjects

77 sujets IRAMIS

Dernière mise à jour : 23-06-2018


• Analytic chemistry

• Atomic and molecular physics

• Chemistry

• Instrumentation

• Materials and applications

• Mesoscopic physics

• Molecular biophysics

• Physical chemistry and electrochemistry

• Plasma physics and laser-matter interactions

• Radiation-matter interactions

• Soft matter and complex fluids

• Solid state physics, surfaces and interfaces

• Theoretical Physics

• Ultra-divided matter, Physical sciences for materials

 

Coupling between spin and lattice degrees of freedom in unconventional magnets

SL-DRF-18-0726

Location :

Laboratoire Léon Brillouin

Groupe 3 Axes

Saclay

Contact :

Sylvain PETIT

Starting date : 01-10-2018

Contact :

Sylvain PETIT

CEA - DRF/IRAMIS/LLB

01 69 08 60 39

Thesis supervisor :

Sylvain PETIT

CEA - DRF/IRAMIS/LLB

01 69 08 60 39

Personal web page : http://www-llb.cea.fr/Phocea/Membres/Annuaire/index.php?uid=spetit

Laboratory link : http://www-llb.cea.fr/Phocea/Vie_des_labos/Ast/ast_groupe.php?id_groupe=530

Metal Organic frameworks for new generation of Li-air batteries

SL-DRF-18-0302

Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l'Energie

Laboratoire d'étude des éléments légers

Saclay

Contact :

Suzy SURBLE

Hicham KHODJA

Starting date : 01-10-2018

Contact :

Suzy SURBLE

CEA - DRF/IRAMIS/NIMBE/LEEL

+ 33 1 69 08 81 90

Thesis supervisor :

Hicham KHODJA

CEA - DRF/IRAMIS/NIMBE/LEEL

01 69 08 28 95

Personal web page : http://iramis.cea.fr/nimbe/Pisp/suzy.surble/

Laboratory link : http://iramis.cea.fr/nimbe/leel/

Energy storage will be more essential in the future than it has never been in the past. Therefore, the development of alternative energy is of the utmost importance because our society needs to produce, transport, consume and store energy to keep its high technological level and well-being. Lithium-ion technology holds in this area a prominent place on the market. Nevertheless, its specific capacity and energy density seem to reach their limits and will be insufficient for the long-term needs of our society. It is therefore necessary to develop a new technology of batteries offering new prospects for storage capacity and safety, particularly in the automotive field. The Li - air batteries are receiving intense interest today due to potentially much higher gravimetric energy storage density compared to others technologies (1700 Wh/kg vs 160 Wh/kg for current Li-ion batteries). However, there are numerous scientific and technical challenges that must be overcome, the most important being the rapid loss of electrochemical performance after only few cycles. The use of metal-organic framework (MOF) for electrochemical applications is a breakthrough. These compounds have low density, high surface area and high porosity. Their open structure provides a host network for the lithium diffusion and a good diffusion of oxygen. A sufficient space is also available for the discharge products.

The objective of the thesis will be to synthesize new MOF materials presenting good electrochemical performances. Conventional techniques such as X-ray diffraction, electrochemical and impedance measurements will be used to characterize these materials. For the most promising structures, the electrode formulation will be optimized in order to obtain a complete assembly of Li-air battery.

Key words: lithium-air battery, MOFs (Metal Organic Frameworks), structural and electrochemical characterizations.

In situ analysis of an organic redox flow cell through magnetic resonance and additive manufacturing

SL-DRF-18-0330

Research field : Analytic chemistry
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l'Energie

Laboratoire Structure et Dynamique par Résonance Magnétique (LCF)

Saclay

Contact :

Lionel DUBOIS

Patrick BERTHAULT

Starting date : 01-10-2018

Contact :

Lionel DUBOIS

CEA - DSM/INAC/SyMMES/CAMPE

04 38 78 92 57

Thesis supervisor :

Patrick BERTHAULT

CEA - DRF/IRAMIS/NIMBE/LSDRM

+33 1 69 08 42 45

Personal web page : http://iramis.cea.fr/Pisp/patrick.berthault/

Laboratory link : http://iramis.cea.fr/nimbe/lsdrm/

In the thesis project we want to take advantage of our recent advances in 3D printing combined with the development of integrated dynamic nuclear magnetic resonance devices to study operating systems by NMR and perform in situ or operando experiments. We wish to apply these developments according to an important area of ??research in the field of energy: the identification and study of migrations of different molecular species generated during the operation of an organic redox flow battery (RFBO).



In this purpose it will be necessary to build a mini battery that will be integrated within a conventional NMR magnet. The solution flow in each of the compartments will be driven using our patented mini bubble Pump approach. Here the modularity of our low cost system will allow us to follow spectroscopy and imaging different molecular species in several positions of the battery. The components and geometry will be adapted to organic flow cells, the main goal being to understand and analyze the degradation mechanism and products of the redox molecule (anthraquinone derivatives) on the redox cycle.



The work requested from the doctoral student will go from a strong implication in the design of the mini-battery, to its construction and the magnetic resonance studies. In this area, dedicated protocols and new sequences, using both spectroscopic and recent MRI techniques, will have to be developed.

Digital Microfluidic hyphanated ICPMS : Droplet Generator introduction system study

SL-DRF-18-0452

Research field : Analytic chemistry
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l'Energie

Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire

Saclay

Contact :

Valérie GEERTSEN

Starting date : 01-10-2018

Contact :

Valérie GEERTSEN

CEA - DRF/IRAMIS/NIMBE/LIONS

0169084798

Thesis supervisor :

Valérie GEERTSEN

CEA - DRF/IRAMIS/NIMBE/LIONS

0169084798

Personal web page : http://iramis.cea.fr/nimbe/Pisp/valerie.geertsen/

Laboratory link : http://iramis.cea.fr/nimbe/lions/

More : http://iramis.cea.fr/nimbe/Phocea/Vie_des_labos/Ast/ast.php?t=projets&id_ast=2800

In the scope of the “Instrumentation and Detection” Transverse Competency CEA Project a new sample introduction system for inductively coupled mass spectrometer (ICPMS) is developed (Cleverest project). The sample is introduced as a cortege of size and velocity-controlled droplets produced within a water/oil emulsion on a digital microfluidics chip. Each droplet is analyzed by ICPMS. This digital droplet generator is a unique opportunity to better understand the sample ionization within ICP source argon plasma due to the control of droplets’ size, velocity and frequency.



The thesis work will consist in developing and studying digital microfluidic chips with well-defined droplets size. The coupling of such microsystems with the ICP spectrometry will lie at the center of the subject and should allow proposing ways to optimize the ICP ionization in order to increase the sensitivity of the instruments. The study will first focus on homogeneous samples before addressing the encapsulation of single nanoparticles in the drops and it sequential analysis (Single Particle ICPMS).



This interdisciplinary thematic requires team work ability, large scientific curiosity and mind openness. Instrumentation being a large component of this study, the candidate must show a commitment for experimental laboratory work. A competence in microfabrication, 3D printing or analytical chemistry will be fully appreciated.

Spectroscopy and dynamics of molecules in helium droplets

SL-DRF-18-0369

Research field : Atomic and molecular physics
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Saclay

Contact :

Marc BRIANT

Michel MONS

Starting date : 01-09-2018

Contact :

Marc BRIANT

CEA - DSM/IRAMIS/LIDyL/DYR

01 69 08 81 21

Thesis supervisor :

Michel MONS

CEA - DRF/IRAMIS/LIDyL/SBM

01 69 08 20 01

Personal web page : http://iramis.cea.fr/Phocea/Membres/Annuaire/index.php?uid=mbriant

Laboratory link : http://iramis.cea.fr/LIDYL/Phocea/Vie_des_labos/Ast/ast_groupe.php?id_groupe=2038

This Phd subject is a fundamental approach to a better understanding of the triplet states of organic molecules with complete layer. These molecules thus excited are more reactive than in their ground state. Unfortunately, these triplet states are not well known. Also, this Phd subject offers the possibility to overcome this poor knowledge by carrying out the spectroscopy and the dynamics of the triplet states of organic molecules via a resonant excitation (UV, Vis) since the ground state. The molecule will be deposited in a helium cluster. To succeed this direct excitation of the triplet state, it will be necessary to use the particular properties of the quantum medium that are the helium clusters: cooling of the molecule in its electronic and vibrational fundamental state, weak interaction with the host molecule. Because of the long life of the triplet states, it will also be possible to perform the IR spectroscopy of the hosted molecule in its triplet state. The electron relaxation dynamics of the triplet state will be studied later.



Note that the experimental GOUTTELIUM device, on which the spectroscopic part of this thesis will be conducted, is unique in France.

Electronic dynamics of bio-relevant systems: toward a modeling of the deactivation processes of excited states

SL-DRF-18-0674

Research field : Atomic and molecular physics
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Saclay

Contact :

Valérie BRENNER

Starting date : 01-10-2018

Contact :

Valérie BRENNER

CEA - DRF/IRAMIS/LIDyL/SBM

01.69.08.37.88

Thesis supervisor :

Valérie BRENNER

CEA - DRF/IRAMIS/LIDyL/SBM

01.69.08.37.88

Personal web page : http://iramis.cea.fr/Pisp/valerie.brenner/

Laboratory link : http://iramis.cea.fr/LIDyL/SBM/

Many complex molecular systems absorbing light in the near UV spectral range, including those of paramount biological importance, like DNA bases or proteins, are endowed with mechanisms of excited-state deactivation following UV absorption. These mechanisms are of major importance for the photochemical stability of these species since they provide them a rapid and efficient way to dissipate the electronic energy in excess into vibration, thus avoiding photochemical processes to take place and then structural damages which affect the biological function of the system. In this context, the study of gas phase bio-relevant systems such peptides as proteins building blocks should lead to better understanding the photophysical phenomena involved in the relaxation mechanisms of life components. The size of the systems, their flexibility, the existence of non-covalent interactions which governs structures and the nature of the excited states require the use of sophisticated theoretical models in order to characterize the preferentially formed conformations in gas phase as well as to investigate the electronic deactivation mechanisms of the first excited states.



The focus of the PhD project concerns the implementation of a computational strategy to both characterize the first excited states and simulate their potential energy surfaces in order to determine the relaxation pathways. This theoretical research project contains then the development, evaluation and validation of modern quantum chemical methods dedicated to excited states. It will be backed up by key gas phase experiments performed in our group on bio-relevant systems using recent spectroscopic techniques which provide precise data on their spectroscopic properties and their electronic dynamics of relaxation.



Moreover, it will take place in the context of the following of the ANR project, ESBODYR or «Excited States of BiO-relevant systems: towards ultrafast conformational Dynamics with Resolution» (Coord V. Brenner, 2014-2018) and will benefit from an access to the national High Performance Computing resources (GENCI: TGCC/ IDRIS / CINES).

Electronic dynamics of bio-relevant systems: a synergetic experimental and theoretical approach

SL-DRF-18-0678

Research field : Atomic and molecular physics
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Saclay

Contact :

Michel MONS

Valérie BRENNER

Starting date : 01-10-2018

Contact :

Michel MONS

CEA - DRF/IRAMIS/LIDyL/SBM

01 69 08 20 01

Thesis supervisor :

Valérie BRENNER

CEA - DRF/IRAMIS/LIDyL/SBM

01.69.08.37.88

Personal web page : http://iramis.cea.fr/Pisp/valerie.brenner/

Laboratory link : http://iramis.cea.fr/LIDyL/SBM/

More : http://iramis.cea.fr/Pisp/michel.mons/

Many complex molecular systems absorbing light in the near UV spectral range, including those of paramount biological importance, like DNA bases or proteins, are endowed with mechanisms of excited-state deactivation following UV absorption. These mechanisms are of major importance for the photochemical stability of these species since they provide them a rapid and efficient way to dissipate the electronic energy in excess into vibrations, thus avoiding photochemical processes to take place and then structural damages which affect the biological function of the system. In this context, the study of gas phase bio-relevant systems such peptides as proteins building blocks should lead to a better understanding of the photophysical phenomena involved in the relaxation mechanisms of life components. This Ph. D project aims at both investigating the electronic dynamics of bio-relevant model systems, i.e. building block of life components, and documenting the basic phenomena controlling the lifetime of the excited states, through a dual approach using most recent methodological tools, consisting of:



i) An experimental characterization of i) the lifetimes, in nano-, pico- and femtosecond pump-probe experiments, and ii) the nature of the electronic states formed. Sophisticated diagnostic techniques, such as a photo-electron velocity map imaging diagnosis, will be used. These experiments will allow us to identify the relaxation pathways followed by the system, and in particular to assess the role of the several excited states together with the effect of its environment.

ii) A theoretical modeling of the processes involved, in particular to assess the role of specific regions of the potential energy surface (PES), namely the conical intersections, and to determine the motions that trigger deactivation. The systems’ size, their flexibility, the non-covalent interactions, which govern the structures, and the nature of the excited states require the implementation of a computational strategy using sophisticated quantum chemical methods dedicated to excited states (non-adiabatic dynamic, coupled cluster method and multireference configuration interaction method) in order to characterize the first excited states, simulate their PES and eventually determine the relaxation pathways.



Moreover, this work will take place in the following of the ANR project, ESBODYR, for «Excited States of BiO-relevant systems: towards ultrafast conformational Dynamics with Resolution» (Coord V. Brenner, 2014-2018). Finally, the theoretical part will benefit from an access to the national High Performance Computing resources (GENCI: TGCC/ IDRIS / CINES) as well as from access to both the femtosecond SLIC server of IRAMIS (Saclay) and the Laser Center of the University Paris-Sud (CLUPS).

Bacteriostatic polymer films

SL-DRF-18-0680

Research field : Chemistry
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l'Energie

Laboratoire Innovation, Chimie des Surfaces Et Nanosciences

Saclay

Contact :

Geraldine CARROT

Marie-Noelle BELLON-FONTAINE

Starting date : 01-10-2017

Contact :

Geraldine CARROT

CEA - DRF/IRAMIS/NIMBE/LICSEN

01 69 08 21 49

Thesis supervisor :

Marie-Noelle BELLON-FONTAINE

AgroParisTech - MICALIS/ INRA/ AgroParisTech

Personal web page : http://iramis.cea.fr/Phocea/Membres/Annuaire/index.php?uid=carrot

Laboratory link : http://iramis.cea.fr/nimbe/licsen/

Microbial multiplication is one of the most serious concerns for many commercial applications, particularly food packaging where the product deterioration is closely linked to both economic and environmental concerns (decrease of food waste by increasing the DLC, limit date of consumption). In this particular domain, the challenge is double: 1-to limit the growth of the total flora (to prevent the multiplication responsible for alteration), and 2-to preserve a certain amount of endogenous bacteria useful for an appropriate maturation of the fresh food product. The expected effect is therefore more bacteriostatic than fully antibacterial. We need materials that are both contact-active and biocide. In this context, stable cationic polymers are particularly interesting (low MCI in solution, Minimum Concentration for Inhibition) and the challenge here will be to develop a robust and efficient method to graft them onto various substrates such as glass, stainless steel and particularly polyolefins that are widely used in food packaging. This thesis project involves two academic Labs: CEA/NIMBE-LICSEN, expert in surface chemistry and AgroParisTech/INRA-MICALIS specialized in the study of bio-adhesion and biofilms. Industrial partners are also involved in this project.

Radiosensitive polymeric nano-objects

SL-DRF-18-0681

Research field : Chemistry
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l'Energie

Laboratoire Innovation, Chimie des Surfaces Et Nanosciences

Saclay

Contact :

Geraldine CARROT

Jean-Philippe RENAULT

Starting date : 01-10-2017

Contact :

Geraldine CARROT

CEA - DRF/IRAMIS/NIMBE/LICSEN

01 69 08 21 49

Thesis supervisor :

Jean-Philippe RENAULT

CEA - DRF/IRAMIS/NIMBE/LIONS

01 69 08 15 50

This project involves the development of new delivery systems for drugs based on the degradation of polymers by irradiation. This new stimulus has never been explored for such applications. This permits to consider a coupled chemo- and radiotherapy beyond the simple trigger release. The objective is to perform the synthesis of a library of original amphiphilic copolymers, i.e. with a water-soluble/biocompatible part, together with a hydrophobic/radiosensitive part. The self-assembly into micelles or vesicles will lead to objects with a radiosensitive core where the drug will be located. The first advantage of these new systems is to control more finely the targeting of drug to the tumor cells and to avoid the side effects associated with chemotherapy and radiotherapy, by controlling the position of the irradiating beam and/or the absorbed doses.

Innovative Porous Materials for Glycomic Analysis in Hospitals

SL-DRF-18-0235

Research field : Chemistry
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l'Energie

Laboratoire Edifices Nanométriques

Saclay

Contact :

Laurent MUGHERLI

Martine Mayne

Starting date : 01-10-2018

Contact :

Laurent MUGHERLI

CEA - DRF/IRAMIS/NIMBE/LEDNA

0169089427

Thesis supervisor :

Martine Mayne

CEA - DRF/IRAMIS/NIMBE/LEDNA

01 69 08 48 47

Personal web page : http://iramis.cea.fr/Phocea/Membres/Annuaire/index.php?uid=lmugherl

Laboratory link : http://iramis.cea.fr/nimbe/ledna/

More : http://joliot.cea.fr/drf/joliot/Pages/Entites_de_recherche/medicaments_technologies_sante/spi.aspx

Renewable boron and silicon based hydrides for C-O bond reduction in organic wastes

SL-DRF-18-0444

Research field : Chemistry
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l'Energie

Laboratoire de Chimie Moléculaire et de Catalyse pour l'Energie

Saclay

Contact :

Thibault CANTAT

Starting date : 01-10-2018

Contact :

Thibault CANTAT

CEA - DRF/IRAMIS/NIMBE/LCMCE

01 69 08 43 38

Thesis supervisor :

Thibault CANTAT

CEA - DRF/IRAMIS/NIMBE/LCMCE

01 69 08 43 38

Personal web page : http://iramis.cea.fr/Pisp/thibault.cantat/index.html

Laboratory link : http://iramis.cea.fr/Pisp/thibault.cantat/index.html

The conversion of renewable organic feedstocks, including CO2 and biomass, requires the use of reactive, recyclable and, at the same time, energy efficient reductants. While H2 is commonly utilized in some reduction processes, its lack of reactivity, coupled to its mild redox potential, hampers its use in innovative reduction transformations. To circumvent these limitations, boron and silicon based hydrides are appealing, although their production is currently energy intensive and relies on the use of stoichiometric quantities of sodium metal. The doctoral project will tackle the drawbacks in hydrosilylation and hydroboration chemistry by unveiling the first electrocatalytic route to silicon and boron hydrides.

Development of an integrated approach for characterization and quantification of protein surface coverage on antibody-functionalized particles:

SL-DRF-18-0862

Research field : Chemistry
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l'Energie

Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire

Saclay

Contact :

Jean-Philippe RENAULT

Serge PIN

Starting date :

Contact :

Jean-Philippe RENAULT

CEA - DRF/IRAMIS/NIMBE/LIONS

01 69 08 15 50

Thesis supervisor :

Serge PIN

CNRS - UMR 3299

01 69 08 15 49

Personal web page : http://iramis.cea.fr/Phocea/Membres/Annuaire/index.php?uid=jrenault

Laboratory link : http://iramis.cea.fr/nimbe/lions/

The goal of the proposed research therefore is to develop an integrated (i.e. physical and biochemical) approach for quantification of protein surface coverage on antibody-functionalized porous magnetic particles and systematic characterization of the antibodies’ functionality upon their grafting onto the porous structure. This integrated tool will serve to highlight the immunocapture potential of this novel microsphere technology platform compared to the conventional solid ones in diagnostic and biomedical applications.

Combined use of microfluidics and NMR micro-detection for monitoring in situ chemical reactions

SL-DRF-18-0873

Research field : Instrumentation
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l'Energie

Laboratoire Structure et Dynamique par Résonance Magnétique (LCF)

Saclay

Contact :

Patrick BERTHAULT

Starting date : 01-10-2018

Contact :

Patrick BERTHAULT

CEA - DRF/IRAMIS/NIMBE/LSDRM

+33 1 69 08 42 45

Thesis supervisor :

Patrick BERTHAULT

CEA - DRF/IRAMIS/NIMBE/LSDRM

+33 1 69 08 42 45

Personal web page : http://iramis.cea.fr/Pisp/patrick.berthault/

Laboratory link : http://iramis.cea.fr/nimbe/lsdrm/

More : http://www.cortecnet.com

A large number of chemical processes are complex and require for their optimization to understand the reaction mechanisms by real-time observation of intermediate compounds and end products. NMR can perform this task, but this requires taking into account several aspects: to overcome the intrinsic lack of sensitivity of this technique, to bring the detection zone as close as possible to the synthesis reactor and to accurately quantify the data obtained.



Recently LSDRM researchers invented and patented a 3D printed NMR device based on a mini bubble pump associated with fluidics and micro-detection, installable on a commercial probe inside the NMR magnet. An insert version plugged into a micro-imaging probe and a version using an inductive coupling between the micro-coil and the commercial coil (WIFI-NMRS, for 'Wireless Inductive Coupling & Flow for Increased NMR Sensitivity) have been developed.



The system allows a significant improvement of the NMR signal for the slowly relaxing nuclei, since the constituents of the reaction mixture are located in a magnetic field close to that of the NMR study, thus allowing a pre-polarization of the whole solution. Moreover, thanks to the controlled movement of the flow, between two scans the fresh spins replace those previously excited in the detection region; it is therefore not necessary to wait several times for the relaxation time.



The objective of this thesis is to develop a complete system of in situ monitoring of chemical syntheses by NMR in order to provide organic chemists with an indispensable measuring instrument in their daily activities. The student will first focus on the development and optimization of a device comprising the micro-NMR insert located at the NMR probe and consisting of a microfluidic circuit printed in 3D based on a bubble mini-pump and a programmable syringe pump, a micro-coil radio frequency and the associated tuning circuit. In a second step, he/she will be in charge of the design of the complete module comprising, in addition to the micro-NMR insert and the microfluidic injector described above, a reactor placed above or beside the detection coil. He / she will participate in the design of new NMR sequences to make the most of these instrumental developments.

Low-cost Integration of efficient robust and inexpensive catalysts in membrane electrode assembly for PV-Electrolyser technology

SL-DRF-18-1007

Research field : Materials and applications
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l'Energie

Laboratoire Innovation, Chimie des Surfaces Et Nanosciences

Saclay

Contact :

Bruno JOUSSELME

Starting date : 01-10-2018

Contact :

Bruno JOUSSELME

CEA - DRF/IRAMIS/NIMBE/LICSEN

0169 08 91 91

Thesis supervisor :

Bruno JOUSSELME

CEA - DRF/IRAMIS/NIMBE/LICSEN

0169 08 91 91

Personal web page : http://iramis.cea.fr/Pisp/bruno.jousselme/

Laboratory link : http://iramis.cea.fr/nimbe/licsen/

The PhD project will deal with the integration in electrolyser of stable and efficient catalysts based on metal complex catalysts or on materials developed recently by the Institute Català d’Investigació Química (ICIQ), Uppsala University (UU) and CEA-Saclay (CEA) partners. Molecular catalysts, either in their molecular state or immobilized in suitable MOFs or carbon nanotubes, and Metals chalcogenides as molybdenum Sulphide coordination polymers will be investigated for water oxidation and protons reduction. These catalysts will be formulated and deposited either on electrodes or membranes (furnished by University of Stuttgart (USTUTT)) according low cost and manufacturing processes such as inkjet-printing, spray... The optimisation of the catalytic performances of the materials electrodes will be also investigated by the addition of conductive additives and the formatting of the inks. The electrolyser cells fabricated in this work will be ultimately powered by perovskite PV cells developed by Solaronix (SOLAR) and by the Fondazione Istituto Italiano di technologia (IIT).

Quantum heat transport in graphene Van der Waals heterostructures

SL-DRF-18-0412

Research field : Mesoscopic physics
Location :

Service de Physique de l'Etat Condensé

Groupe Nano-Electronique

Saclay

Contact :

François PARMENTIER

Patrice ROCHE

Starting date : 01-10-2018

Contact :

François PARMENTIER

CEA - DRF/IRAMIS/SPEC/GNE

+33169087311

Thesis supervisor :

Patrice ROCHE

CEA - DRF/IRAMIS/SPEC/GNE

0169087216

Laboratory link : http://nanoelectronics.wikidot.com/research

The goal of this project is to explore quantum transport of heat in new states of matter arising in ultra-clean graphene in high magnetic fields, using ultra-sensitive electronic noise measurements.



The ability to obtain ultra-clean graphene (a two-dimensional crystal made of Carbon atoms in a honeycomb lattice) samples has recently allowed the observation of new phases of condensed matter in graphene under high magnetic fields. In particular, new states of the quantum Hall effect were observed at low charge carrier density [1], where interactions and electronic correlations can either make graphene completely electrically insulating, or give rise to the quantum spin Hall effect. In the latter, the bulk of the two-dimensional crystal is insulating, while electronic current is only carried along the edges of the crystal, with opposite spins propagating in opposite directions. The exact nature of those various states is still not fully understood, as one cannot probe the properties of the insulating regions by usual electron transport measurements.



We propose a new approach to probe those phases, based on the measurement of quantum heat flow carried by chargeless excitations such as spin waves, at very low temperature. Our method will consist in connecting the graphene crystal to small metallic electrodes which will be used as heat reservoirs. The temperature of each reservoir will be inferred by ultra-sensitive noise measurements [2], allowing us to extract the heat flow.



The first step of this project will consist in fabricating the samples made of graphene encapsulated in hexagonal boron nitride [3]. This technique, which we have recently developed in our lab, allows to obtain large-area, ultra-clean graphene flakes. In parallel, an experimental platform for low-temperature, high magnetic field, ultra-high sensitivity noise measurements will be set up.



[1] Young et al., Nature 505, 528-532 (2014).

[2] Jezouin, Parmentier et al., Science 342, 601 (2013).

[3] Wang et al., Science 342, 614 (2013).

Out-of-equilibrium thermoelectric transport in quantum conductors

SL-DRF-18-0459

Research field : Mesoscopic physics
Location :

Service de Physique de l'Etat Condensé

Groupe Mésocopie Modélisation et Thermoélectricité

Saclay

Contact :

Geneviève FLEURY

Alexander SMOGUNOV

Starting date : 01-10-2017

Contact :

Geneviève FLEURY

CEA - DRF/IRAMIS/SPEC/GMT

0169087347

Thesis supervisor :

Alexander SMOGUNOV

CEA - DRF/IRAMIS/SPEC/GMT

0169083032

Personal web page : http://iramis.cea.fr/spec/Pisp/genevieve.fleury/

Laboratory link : http://iramis.cea.fr/spec/GMT/

This subject is now receiving CEA funding as a "flagship" topic. The selection of the candidatures received will be made at the beginning of spring 2018.



Seebeck and Peltier thermoelectric effects provide an eco-friendly way of converting heat into electricity and vice-versa. Thus it is possible with the Seebeck effect to harvest waste heat for producing electricity. Conversely, the Peltier effect enables local cooling of a device by investing electrical power. For a long time, thermoelectric conversion has been limited by a poor efficiency and therefore, practical applications have till date remained rare. Interest in the field has been recently rekindled by the discovery of new promising materials, by progress in nanostructuration, and by the growing societal concern about energy issues.



The purpose of this theoretical PhD thesis is to study analytically and numerically thermoelectric conversion in low-dimensional mesoscopic systems. We will consider the regime far from equilibrium where important thermoelectric effects are expected. In particular, we will investigate systems under dynamic time-dependent forcing. From a methodological standpoint, we will use the numerical tools and the analytical formalism developed at CEA-Grenoble (X. Waintal's team) for the study of (out-of-equilibrium) time-resolved quantum transport (see https://kwant-project.org/). We will adapt it to the case of thermoelectric transport and apply it to various systems (quantum dots, quantum point contacts, nanowires…).

Manipulation of the quantum state of individual superconducting excitations in nanowires

SL-DRF-18-0964

Research field : Mesoscopic physics
Location :

Service de Physique de l'Etat Condensé

Groupe Quantronique

Saclay

Contact :

Marcelo GOFFMAN

Starting date : 01-09-2017

Contact :

Marcelo GOFFMAN

CEA - DRF/IRAMIS/SPEC/GQ

0169085529

Thesis supervisor :

Marcelo GOFFMAN

CEA - DRF/IRAMIS/SPEC/GQ

0169085529

Personal web page : http://iramis.cea.fr/Pisp/marcelo.goffman/

Laboratory link : http://iramis.cea.fr/spec/Pres/Quantro/static/index.html

Electrons in superconductors form Cooper pairs that cannot be probed individually because they are delocalized and overlapping. However, localized states appear at weak links between superconducting electrodes. Using atomic contacts as a weak link, we performed the spectroscopy of these localized states [1] and demonstrated the quantum manipulation of a localized Cooper pair [2].

During the internship, we plan to develop similar experiments with InAs semiconducting nanowires. Longer coherence times are expected, and, because of the strong spin-orbit coupling in InAs, one should also be able to manipulate the spin of localized electrons.



The student will be integrated in an active research group on quantum electronics and get acquainted with advanced concepts of quantum mechanics and superconductivity. He/she will also learn several experimental techniques: low temperatures, low-noise and microwave measurements, and nanofabrication.



[1] L. Bretheau et al., “Exciting Andreev pairs in a superconducting atomic contact”

Nature 499, 312 (2013). arXiv:1305.4091

[2] C. Janvier et al., “Coherent manipulation of Andreev states in superconducting atomic contacts”

Science 349, 1199 (2015), arXiv:1509.03961

Microwave detection of a single rare earth ion

SL-DRF-18-0950

Research field : Mesoscopic physics
Location :

Service de Physique de l'Etat Condensé

Groupe Quantronique

Saclay

Contact :

Patrice BERTET

Denis VION

Starting date : 01-10-2018

Contact :

Patrice BERTET

CEA - DRF/IRAMIS

0169085529

Thesis supervisor :

Denis VION

CEA - DRF/IRAMIS/SPEC/GQ

2 5529

Personal web page : http://iramis.cea.fr/spec/Pres/Quantro/static/people/denis-vion/index.html

Laboratory link : http://iramis.cea.fr/spec/Pres/Quantro/static/index.html

The goal of this PhD thesis is to detect a single rare earth ion implanted in a host crystal, by improving the electron spin resonance (ESR) technique: The spin used will be an Er3+ coupled to a superconducting microwave resonator with a very low impedance, including a 200nm x 50 nm x 15 nm constriction placed about 20 nm above the spin. The spin-resonator system will be measured at 20 mK using a parametric amplifier working close to the quantum limit.

DNA compaction induced by a bacterial amyloid

SL-DRF-18-0270

Research field : Molecular biophysics
Location :

Laboratoire Léon Brillouin

Groupe Biologie et Systèmes Désordonnés

Saclay

Contact :

Véronique ARLUISON

Starting date : 01-09-2018

Contact :

Véronique ARLUISON

Université Paris VII - DRF/IRAMIS/LLB/GBSD

01 69 08 32 82

Thesis supervisor :

Véronique ARLUISON

Université Paris VII - DRF/IRAMIS/LLB/GBSD

01 69 08 32 82

Personal web page : http://www-llb.cea.fr/Phocea/Membres/Annuaire/index.php?uid=varluiso

Laboratory link : http://www-llb.cea.fr/

More : https://www.synchrotron-soleil.fr/

In bacteria, the genetic material is often in a crowded and congested state. For instance, the size of the bacterial nucleoid, the structure that contains the bacterial chromosome associated with proteins, is typically sub-micron whereas the length of the DNA is around 1 mm. The genome is hence compacted by a factor of thousand.

Expected breakthroughs of the PhD project are to develop and to couple methods for the investigation of nucleoprotein structures. A multidisciplinary approach will be developed at the Leon Brillouin laboratory in collaboration with a group at SOLEIL Synchrotron (DISCO beamline). The PhD student will investigate the effect of protein-mediated bridging on the structural properties of bacterial DNA. In particular, we aim to study a new way of DNA structuring by a bacterial protein forming amyloid structures, called Hfq. DNA condensation induced by amyloids associated to neuropathologies has been reported previously. Here the amyloid domain of Hfq serves the physiology of the cell to ensure DNA compaction. Examining the interaction of Hfq with DNA will thus be paramount for understanding bacterial nucleoid compaction and functional consequences. The expected benefits for this PhD project will be twice: the development of methods for the analysis of biological nanostructures, but also new opportunities for the development of antibiotics.

High Energy Supercapacitors and pseudo-supercapacitors based on p- and n-dopable materials

SL-DRF-18-0799

Research field : Physical chemistry and electrochemistry
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l'Energie

Laboratoire Edifices Nanométriques

Saclay

Contact :

Mathieu PINAULT

Starting date : 01-10-2018

Contact :

Mathieu PINAULT

CEA - DRF/IRAMIS/NIMBE/LEDNA

01-69-08-91-87

Thesis supervisor :

Mathieu PINAULT

CEA - DRF/IRAMIS/NIMBE/LEDNA

01-69-08-91-87

Personal web page : http://iramis.cea.fr/Pisp/mathieu.pinault/

Laboratory link : http://iramis.cea.fr/nimbe/ledna/

More : https://www.u-cergy.fr/fr/laboratoires/lppi/themes-de-recherche/theme-ii.html

The aerosol-assisted CVD method (Chemical Vapor Deposition) developed at CEA Saclay provides dense mats of vertically aligned carbon nanotubes (VACNT) especially on aluminum support. The applications of these nanostructured materials are particularly promising in the field of electrochemical energy storage using either nanotubes alone (targeted application power) or by associating them with electronically conductive polymers (PCE, targeted energy application). In collaboration with the University of Cergy-Pontoise (Laboratoire LPPI), we will improve the performances by working on electrode materials. Significant advances have already been made on the positive electrode and the objective is now to work on the negative one and in particular on the doping of the various elements or post treatments. We will first develop controlled growth of VACNT containing heteroatoms (N, B) on substrates of interest for the elaboration of supercapacitor electrodes while controlling their characteristics (length, diameter, density). In parallel, we will associate the VACNT with n-doped ECP through electrochemical deposition. These new nanostructured electrodes will be studied and associated to realize supercapacitors in the form of coin cell in order to determine their Energy/Power performances.

Electrochemical microscopy investigation of the multiphasic transport within an electrocatalytique layer

SL-DRF-18-0442

Research field : Physical chemistry and electrochemistry
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l'Energie

Laboratoire Innovation, Chimie des Surfaces Et Nanosciences

Saclay

Contact :

Renaud CORNUT

Bruno JOUSSELME

Starting date : 01-09-2018

Contact :

Renaud CORNUT

CEA - DRF/IRAMIS/NIMBE/LICSEN

01 69 08 91 91

Thesis supervisor :

Bruno JOUSSELME

CEA - DRF/IRAMIS/NIMBE/LICSEN

0169 08 91 91

Personal web page : http://iramis.cea.fr/Pisp/renaud.cornut/

Laboratory link : http://iramis.cea.fr/nimbe/licsen/

The emergence of hydrogen as an energy vector must help to stop pollution issued from the use of carbon-based energy sources in transport. In vehicles the conversion to electricity is achieved with proton exchange membrane fuel cells.



The aim of the project is to make them compatible with mass market by providing competitive cathodes containing inexpensive catalytic nano-objects. A huge diversity of starting materials, combinations of materials and processing conditions are possible, and identifying the optimal strategy at each step is presently very challenging. To manage this, we first set up an electroanalytical platform to evaluate in routine the effective electrochemical properties of multifunctional materials used in fuel cells. We then produce many different materials in a combinatorial fashion, the analysis of which permits to understand the way nano-objects assemble into electrocatalytic materials. From this, we rationalize the different processing steps and optimize the performances, with special care to the ageing of the materials.

Multi-scale and conformation-resolved dynamics of the electronic relaxation in flexible molecules

SL-DRF-18-0775

Research field : Physical chemistry and electrochemistry
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Saclay

Contact :

Lionel POISSON

Eric GLOAGUEN

Starting date : 01-10-2018

Contact :

Lionel POISSON

CNRS-UMR9222 - DSM/IRAMIS/LIDYL/DYR

01 69 08 51 61

Thesis supervisor :

Eric GLOAGUEN

CNRS - DSM/IRAMIS/LIDyL/SBM

01 69 08 35 82

Personal web page : http://iramis.cea.fr/Pisp/34/lionel.poisson.html

Laboratory link : http://iramis.cea.fr/LIDYL/index.php

More : http://iramis.cea.fr/Pisp/70/eric.gloaguen.html

Flexible molecules are ubiquitous in Nature (proteins, sugars, ...) and are at the origin of many applications (drugs, molecular machines, ...). By definition, these molecules exist in several conformations that each have physical, chemical or biological properties which can vary greatly from one conformation to another. Among these properties, photoexcitation and relaxation of the electronic states are particularly sensitive to conformation: for example, the lifetime of the first excited electronic state can vary with the conformation by several orders of magnitude. However, the experimental characterisation of such conformational effects on the excited states remains rare due to the difficulty to specifically study one conformation present in a conformational mixture. This thematic is still poorly documented despite i) a need for experimental results to help the development of theoretical models, and ii) a lack of knowledge in a field where fundamental (conical intersections, ultrafast phenomena) and application (photostability, energy transfer) issues are important.



In this context, the LIDYL laboratory brings together several experimental apparatus allowing an original multi-scale (ns-fs) and conformation-resolved study of the dynamics of the electronic relaxation in flexible molecular systems. The research program will focus on biologically-relevant systems and molecular complexes, and will target:



- the observation of conformer-dependent dynamic processes and their rationalisation.

- the characterization of species previously inaccessible to conventional detection techniques.

Catalytic activity of Platinum-free active layers for Proton Exchange Membrane Fuel Cells (PEMFC)

SL-DRF-18-0895

Research field : Physical chemistry and electrochemistry
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l'Energie

Laboratoire Innovation, Chimie des Surfaces Et Nanosciences

Saclay

Contact :

Renaud CORNUT

Bruno JOUSSELME

Starting date : 01-09-2018

Contact :

Renaud CORNUT

CEA - DRF/IRAMIS/NIMBE/LICSEN

01 69 08 91 91

Thesis supervisor :

Bruno JOUSSELME

CEA - DRF/IRAMIS/NIMBE/LICSEN

0169 08 91 91

Personal web page : http://iramis.cea.fr/Pisp/renaud.cornut/

Laboratory link : http://iramis.cea.fr/nimbe/licsen/

The future of energy supply depends on innovative breakthroughs regarding the design of efficient systems for the conversion and storage of energy. In this field, electrocatalytic systems are at the cornerstone of many related challenges in fuel cells since they offer suitable solutions for performing very complex reactions. The present project introduces an original strategy based on Scanning Electrochemical Microscopy (SECM)and numerical simulation for the finding of low cost elementary bricks used to form electrocatalytic layers through the combined analysis of individual nano-objects. It will permit to find new electrocatalytic species, and this will lead to electrocatalytic layers having improved performances.

Analysis of complex spectra in highly-ionized plasmas : applications to fusion science and astrophysics

SL-DRF-18-0627

Research field : Plasma physics and laser-matter interactions
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Matière à Haute Densité

Saclay

Contact :

Michel POIRIER

Starting date : 01-10-2018

Contact :

Michel POIRIER

CEA - DRF/IRAMIS/LIDyL/MHDE

+33 (0)1 69 08 46 29

Thesis supervisor :

Michel POIRIER

CEA - DRF/IRAMIS/LIDyL/MHDE

+33 (0)1 69 08 46 29

Personal web page : http://iramis.cea.fr/lidyl/Phocea/Membres/Annuaire/index.php?uid=poirier

Laboratory link : http://iramis.cea.fr/LIDYL/MHDE/

A vast range of topics in physics such as the star internal structure, the X-ray emission of accretion disks, the dynamics of inertial confinement fusion, or new radiation sources requires an accurate knowledge of the radiative properties of hot plasmas. Such plasmas exhibit spectra consisting of a large number of lines often merging in unresolved arrays. Statistical methods are used for the interpretation of such spectra. Using second quantization and tensor algebra techniques, one may obtain quantities such as the average and variance of transition energies inside these unresolved arrays. Though a wide literature exists on this subject, certain types of transitions, e.g., magnetic dipole transitions inside a given configuration or processes involving several electron jumps, have not been considered up to now. In addition to this analytical study, a numerical work involving the Flexible Atomic Code will be proposed for this thesis. This study will concern plasmas either at thermodynamic equilibrium, or out of equilibrium, where level population is obtained by solving a system of kinetic equations. Several applications may be foreseen: interpretation of recent opacity measurements performed on LULI2000 laser at Ecole Polytechnique, determination of radiative power losses in a tungsten plasma to characterize tokamak operation, or the open subject of the characterization of photoionized silicon plasma analyzed in Sandia Z-pinch in connection with astrophysical observations.

Tunable attosecond pulses for the study of photoionization dynamics

SL-DRF-18-0844

Research field : Radiation-matter interactions
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Attophysique

Saclay

Contact :

Pascal SALIERES

Starting date : 01-10-2018

Contact :

Pascal SALIERES

CEA - DRF/IRAMIS/LIDyL/ATTO

0169086339

Thesis supervisor :

Pascal SALIERES

CEA - DRF/IRAMIS/LIDyL/ATTO

0169086339

Personal web page : http://iramis.cea.fr/Pisp/pascal.salieres/

Laboratory link : http://iramis.cea.fr/LIDYL/ATTO/

More : http://attolab.fr/

Summary :



Using tunable attosecond pulses produced with an optical parametric amplifier (OPA) pumped by an intense Titanium:Sapphire laser (ATTOLab Excellence Equipment), the student will investigate the ionization dynamics of atomic and molecular gases close to resonances. The objective is to follow in real time the electron ejection and to measure the buildup of the resonance profile.



Detailed summary :



Recently, the generation of sub-femtosecond pulses, so-called attosecond pulses (1 as=10-18 s), has made impressive progress. These ultrashort pulses open new perspectives for the exploration of matter at unprecedented timescale. Their generation result from the strong nonlinear interaction of short intense infrared (IR) laser pulses (~20 femtoseconds) with atomic or molecular gases. High order harmonics of the fundamental frequency are produced, covering a large spectral bandwidth in the extreme ultraviolet (XUV) range. In the temporal domain, this coherent radiation forms a train of 100 attosecond pulses [1].



With such attosecond pulses, it becomes possible to investigate the fastest dynamics in matter, i.e., electronic dynamics that occur naturally on this timescale. Attosecond spectroscopy thus allows studying fundamental processes such as photo-ionization, in order to answer questions such as: how long does it take to remove one electron from an atom or a molecule? More precisely: how long does it take for an electron wavepacket produced by absorption of an attosecond pulse to exit the atomic/molecular potential? The measurement of such tiny ionization delays is currently a “hot topic” in the scientific community. In particular, the study of the ionization dynamics close to resonances would give access to detailed information on the atomic/molecular structure, such as the electronic rearrangements in the remaining ion upon electron ejection. Recently, we have studied an auto-ionizing resonance, so-called “Fano resonance”. We have shown through 2-photon XUV+IR ionization that it is possible to observe in real time the buildup of the resonance profile [2].



The objective of the thesis is to generalize the technique to the study of other types of atomic/molecular resonances, such as shape resonances. To this end, tunable attosecond pulses will be generated using the mid-IR [1.2-2µm] radiation from an optical parametric amplifier (OPA) pumped by an intense Titanium:Sapphire laser. Finally, the measurement of the photoelectron angular distribution, in combination with the temporal information detailed above, will allow the reconstruction of the full 3D movie of the electron ejection.

The experimental work will include the operation of a setup installed in the FAB1 laser of ATTOLab allowing: i) the generation of attosecond XUV radiation, ii) its characterization using quantum interferometry, iii) its use in photo-ionization spectroscopy (electron detection). The theoretical aspects will also be developed. The student will be trained in ultrafast optics, atomic and molecular physics, quantum chemistry, and will acquire a good mastery of charged particle spectrometry. A background in ultrafast optics, nonlinear optics, atomic and molecular physics is required.

Part of this work will be performed in collaboration with partner French laboratories (ANR CIMBAAD) and members of the MEDEA European Network through joint experiments in the different associated laboratories (Milano, Lund).



References :

[1] Y. Mairesse, et al., Science 302, 1540 (2003)

[2] V. Gruson, et al., Science 354, 734 (2016)

UV-induced processes in guanine quadruplexes studied by time-resolved optical spectroscopy: from photon absorption to radical reactivity

SL-DRF-18-0975

Research field : Radiation-matter interactions
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Saclay

Contact :

Dimitra MARKOVITSI

Starting date : 01-09-2018

Contact :

Dimitra MARKOVITSI

CNRS - LIDYL

0033169084644

Thesis supervisor :

Dimitra MARKOVITSI

CNRS - LIDYL

0033169084644

Personal web page : http://iramis.cea.fr/Pisp/18/dimitra.markovitsi.html

Laboratory link : http://iramis.cea.fr/LIDYL/Phocea/Vie_des_labos/Ast/ast_groupe.php?id_groupe=575

Guanine Quadruplexes (G4) are four-stranded structures formed by guanine rich DNA sequences. They have been correlated with the oxidative damage which perturbs biological functions. In addition, G4 structures are studied in respect to their applications in molecular electronics and nanotechnologies.

The objective of the thesis is to study the generation and the reactivity of guanine radicals (including electron holes, important in charge transport) induced by absorption low energy UV radiation by G4. The investigation will involve the use of several experimental and computational techniques:

o The electrons ejected by photo-ionization and the resulting base radicals will be studied by time-resolved absorption spectroscopy and time-resolved circular dichroism, from nanoseconds to milliseconds.

o The dynamics of the excited states, expected to play a role in the photo-ionization process, will be studied by fluorescence spectroscopy, from femtoseconds to nanoseconds.

o The observed optical spectra will be interpreted by means of quantum chemistry methods.

o The reaction products resulting from UV-induced radicals will be identified using analytical methods.

Attosecond XUV pulses carrying an angular momentum: synthesis and novel spectroscopies

SL-DRF-18-0221

Research field : Radiation-matter interactions
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Attophysique

Saclay

Contact :

Thierry RUCHON

Starting date : 01-09-2018

Contact :

Thierry RUCHON

CEA - DRF/IRAMIS/LIDyL/ATTO

0169087010

Thesis supervisor :

Thierry RUCHON

CEA - DRF/IRAMIS/LIDyL/ATTO

0169087010

Personal web page : http://iramis.cea.fr/LIDYL/Pisp/thierry.ruchon/

Laboratory link : http://iramis.cea.fr/LIDYL/ATTO/

Light in the extreme ultraviolet (XUV) is a universal probe of mater, may it be in diluted or condensed phase: photons associated with this spectral range carry energy of 10 to 100 eV, sufficient to directly ionize atoms, molecules or solids. Large scale instruments such as synchrotrons or the lately developed free electron lasers (FEL) work in this spectral range and are used to both study fundamental light matter interaction and develop diagnosis tools. However these instruments do not offer the temporal resolution require to study light matter interactions at their ultimate timescales, which is in the attosecond range (1as = 10^-18s). An alternative is offered by the recent development of XUV sources based on high order harmonic generation (HHG). They are based on the extremely nonlinear interaction of a femtosecond intense laser beam with a gas target. Our laboratory has pioneered the development, control and design of these sources providing XUV attosecond pulses.



During this PhD project, we will develop specific setups to allow these attosecond pulse to carry angular momenta, may it be spin or orbital angular momenta. This will open new applications roads through the observations of currently ignored spectroscopic signatures. On the one hand, the fundamental aspects of the coupling of spin and orbital angular momentum of light in the highly nonlinear regime will be investigated, and on the other hand, we will tack attosecond novel spectroscopies, may it be in diluted or condensed phase. In particular, we will chase helical dichroism, which manifest as different absorptions of beams carrying opposite orbital angular moments. These effects are largely ignored to date.



The student will acquire practical knowledge about lasers, in particular femtosecond lasers, and hands on spectrometric techniques of charged particles. He/she will also study strong field physical processes which form the basis for high harmonic generation. He/she will become an expert in attosecond physics. The acquisition of analysis skills, computer controlled experiments skills will be encouraged although not required.

Full subject available at http://iramis.cea.fr/LIDYL/Pisp/thierry.ruchon/.

Plasma mirrors on-chip : “towards extreme intensity light sources and table-top particle accelerators”

SL-DRF-18-0432

Research field : Radiation-matter interactions
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Physique à Haute Intensité

Saclay

Contact :

Henri VINCENTI

Guy BONNAUD

Starting date : 01-10-2018

Contact :

Henri VINCENTI

CEA - DRF/IRAMIS/LIDyL/PHI

0169080376

Thesis supervisor :

Guy BONNAUD

CEA - DRF/IRAMIS/LIDyL/PHI

0169088140

Personal web page : http://iramis.cea.fr/Pisp/henri.vincenti/

Laboratory link : http://iramis.cea.fr/LIDYL/PHI/

More : https://www.picsar.net

With the advent of PetaWatt (PW) class lasers capable of achieving light intensities of 10^22W.cm-2 at which matter turns into a plasma, Ultra-High Intensity (UHI) physics now aims at solving two major challenges: can we produce high-charge compact particle accelerators with high-beam quality that will be essential to push forward the horizons of high energy science? Can we reach extreme light intensities approaching the Schwinger limit 10^29W.cm-2, beyond which light self-focuses in vacuum and electron-positrons pairs are produced? Solving these major questions with the current generation of high-power lasers will require conceptual breakthroughs that will be developed during this PhD.



In particular, the goal of this PhD proposal is to demonstrate that so-called ‘relativistic plasma mirrors’, produced when a high-power laser hits a solid target, can provide simple and elegant paths to solve these two challenges.  Upon reflection on a plasma mirror surface, lasers can produce high-charge relativistic electron bunches and bright short-wavelength attosecond harmonic beams. Could we use plasma mirrors to tightly focus harmonic beams and reach extreme light intensities, potentially approaching the Schwinger limit? Could we employ plasma mirrors as high-charge electron injectors in a PW laser capable of delivering accelerating gradients of 100TV.m-1, or in a laser wakefield accelerator, to build ultra-compact particle accelerators?



The mission of the PhD candidate will be to answer these two interrogations ‘on-chip’ using massively parallel simulations on the largest supercomputers in the world. To this end, the successful candidate will make use of our recent transformative developments in ‘first principles’ Particle-In-Cell (PIC) simulations of UHI laser-plasma interactions that enabled the 3D modelling of plasma mirror sources with high-fidelity on current petascale and future exascale supercomputers. These developments were recently implemented, validated and tested in our code PICSAR (https://www.picsar.net). Armed with PICSAR, the candidate will model novel schemes employing plasma mirrors to address the two UHI challenges introduced above.

High energy chemistry ; Impact of inner shell ionizations on biological molecules

SL-DRF-18-0325

Research field : Radiation-matter interactions
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l'Energie

Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire

Saclay

Contact :

Jean-Philippe RENAULT

Marie-Anne Hervé du Penhoat

Starting date : 01-09-2018

Contact :

Jean-Philippe RENAULT

CEA - DRF/IRAMIS/NIMBE/LIONS

01 69 08 15 50

Thesis supervisor :

Marie-Anne Hervé du Penhoat

UPMC - IMPMC

+33 1 44 27 72 05

Personal web page : http://iramis.cea.fr/Phocea/Membres/Annuaire/index.php?uid=jrenault

Laboratory link : http://iramis.cea.fr/nimbe/lions/

The aim of this PhD project is to understand the chemical effects of inner shell ionizations. Indeed such ionizations that inject hundreds of eV in biomolecules can have important radiobiological consequences, but the mechanisms leading to biomolecule damages remain to be deciphered.



We will carry on irradiation of water and solutions of biological molecules in water using soft X rays produced by SOLEIL synchrotron. New spectroscopic techniques sensitive to changes in the biological molecules upon irradiation will also be investigated. These data will be compared to ab initio molecular dynamics calculations.

Fast and innovative understanding of ageing processes in lithium-ion batteries by radiolysis

SL-DRF-18-0424

Research field : Radiation-matter interactions
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l'Energie

Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire

Saclay

Contact :

Sophie LE CAER

Starting date : 01-09-2018

Contact :

Sophie LE CAER

CNRS - DRF/IRAMIS/NIMBE/LIONS

01 69 08 15 58

Thesis supervisor :

Sophie LE CAER

CNRS - DRF/IRAMIS/NIMBE/LIONS

01 69 08 15 58

Personal web page : iramis.cea.fr/Pisp/sophie.le-caer

Laboratory link : http://iramis.cea.fr/nimbe/Phocea/Vie_des_labos/Ast/ast_groupe.php?id_groupe=50

Ageing and safety issues are a critical challenge for lithium-ion batteries. Recently we have demonstrated for the first time that radiolysis (i.e. the chemical reactivity induced by the interaction between ionizing radiation and matter) is a powerful tool for a short-time (minutes-days) identification of the by-products arising from the degradation of the electrolyte of a lithium-ion battery, after several weeks or months of cycling.



The aim of the present PhD thesis is to extend the radiolysis approach to:

* screen electrolytes and combinations of electrolyte and active materials to identify the most robust ones. Reaction mechanisms induced by ionizing radiation will be studied in details for the most promising electrolytes identified;

* study carefully the interfacial processes (electrode/electrolyte) with negative and positive électrodes for the most interesting systems previously identified.



A global and detailed picture of reaction mechanims at stake in lithium-ion batteries will thus be provided. Moreover, the systems; which are the most robust towards ionizing radiation and thus to electrolysis, will be identified and carefully studied.

Spatio-temporal control of high harmonic generation in semiconductors for attosecond pulse emission

SL-DRF-18-0961

Research field : Radiation-matter interactions
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Attophysique

Saclay

Contact :

Willem Boutu

Hamed MERDJI

Starting date : 01-10-2018

Contact :

Willem Boutu

CEA - DRF/IRAMIS/LIDYL/ATTO

0169085163

Thesis supervisor :

Hamed MERDJI

CEA - DRF/IRAMIS/LIDyL/ATTO

0169085163

Personal web page : http://iramis.cea.fr/LIDYL/en/Phocea/Pisp/index.php?nom=willem.boutu

Laboratory link : http://iramis.cea.fr/LIDYL/Phocea/Vie_des_labos/Ast/ast_groupe.php?id_groupe=1149

Ultrafast nano-photonics science is emerging thanks to the extraordinary progresses in nano-fabrication and ultrafast laser science. Boosting extremely intense electric fields in nano-structured photonic devices has the potential of creating nano-localized sources of energetic photons or particles opening vast applications in science and in the industry. Optoelectronic is extending to the highly non-linear regime. A recent impact of this capability of controlling the response of above band gap electrons under strong fields is the emergence of high harmonic generation (HHG) in crystal [1-6]. 2D and 3D semiconductors exhibits properties of high electron mobility that allows to drive intense electrons currents coherently in the conduction band. HHG are emitted when those electrons recombine to the valence band. This is a pure above band gap non-perturbative phenomena which occurs efficiently in a few 10s to 100s nanometer exit layer of a crystal and down to an atomically thin layer [5,6]. The strong electron current from which HHG originate can be manipulated in space and time. The project will focus in the strong localization in space, and time, at the single optical cycle scale [7,8], of the harmonic generation process. This control can not only revolutionize attosecond science but also prepare a new generation of ultrafast visible to X-ray opto-electronic devices. Based on the CEA group expertise, experimental and theoretical resources [9-12], the fellow will seek for efficient ways to boost the interaction regime through plasmonic amplification and field confinement for the generation of nanoscale, attosecond high harmonic sources in semiconductors. A specific focus will be on 2D materials like graphene, MoS2 and h-BN. Attosecond pulse generation will also be investigated by using harmonic phase measurements available at CEA (RABBITT, FROG techniques). We will also develop an original nanostructured sample that will allow to generate an attosecond light house inside the semiconductor to isolate single attosecond burst of light.

The research will take place in NanoLight facility, a brand new lab equipped with two laser sources: a 100kHz few optical cycles mid-infrared intense OPCPA (tunable from 1,5 to 3.4 µm wavelength) and a 2µm intense MHz rep/rate few optical cycles fiber laser and and ATTOLAB facility equipped with CEP stable Ti:Sa lasers and attosecond metrology.

1. Ghimire, S. et al. Observation of high-order harmonic generation in a bulk crystal. Nat. Phys. 7, 138–141 (2011).

2. Luu, T. T. et al. Extreme ultraviolet high-harmonic spectroscopy of solids. Nature 521, 498–502 (2015).

3. Ndabashimiye, G. et al. Solid-state harmonics beyond the atomic limit. Nature 534, 520–523 (2016).

4. You, Y. S., et al. Anisotropic high-harmonic generation in bulk crystals. Nat. Phys. 13, 345–349 (2017).

5. Liu H. et al. High-harmonic generation from an atomically thin semiconductor. Nature Physics 13, 262–265 (2017).

6. Yoshikawa, N., et al. High-harmonic generation in graphene enhanced by elliptically polarized light excitation. Science, 356, 736-738 (2017).

7. Hohenleuter, M. et al. Real-time observation of interfering crystal electrons in high-harmonic generation. Nature 523, 572-575 (2015).

8. Langer, F. et al., Lightwave-driven quasiparticle collisions on a subcycle timescale. Nature 533, 225–229 (12 May 2016).

9. Franz et al. submitted to Science Advances arXiv:1709.09153

10. Shaaran, T et al. Nano-Plasmonic near Field Phase Matching of Attosecond Pulses. Scientific Reports 2017, 7, 6356.

11. Shi, L. et al. Self-Optimization of Plasmonic Nanoantennas in Strong Femtosecond Fields. Optica 2017, 4, 1038–1043.

12. Nicolas R. et al. Plasmon-Amplified Third Harmonic Generation in metal/dielectric resonators, submitted to ACS Nano (2017).

Data-driven model-learning for suspensions of micro-swimmers

SL-DRF-18-0902

Research field : Soft matter and complex fluids
Location :

Service de Physique de l'Etat Condensé

Systèmes Physiques Hors-équilibre, hYdrodynamique, éNergie et compleXes

Saclay

Contact :

Hugues CHATE

Starting date : 01-09-2018

Contact :

Hugues CHATE

CEA - DRF/IRAMIS/SPEC/SPHYNX

0169087535

Thesis supervisor :

Hugues CHATE

CEA - DRF/IRAMIS/SPEC/SPHYNX

0169087535

Laboratory link : http://iramis.cea.fr/spec/SPHYNX/

The past ten years have seen the emergence of Active Matter – composed of particles that convert energy from an ambient source into systematic movement – as a distinct topic in nonequilibrium statistical physics, motivated mainly by the need to understand and imitate individual and collective motility. Experiments are still relatively few, but, increasingly, large datasets obtained in controlled conditions are obtained with the aim of testing theoretical ideas and results. The time is ripe to try to build models from data, aiming at full quantitative agreement so that the effect of experimental control parameters on model parameters is made explicit. This is challenging and important since models, especially continuous ones, typically contain many terms parameters so that there is no one-to-one correspondence with experimental ones.



We will use high-throughput experimental data on bacterial suspensions (‘big data’, from collaborators in Shanghai and Hong Kong) to build quantitative models/theories.



The PhD work will consist of following two main avenues toward the overarching goal of building a direct quantitative link between experiments and theory. The first one, based on traditional model building based on multidimensional optimization of a set of target quantifiers, is already under way. The second one, based on automatic model learning, is more challenging and risky, as it will explore how to use machine-learning techniques to build a model ‘automatically’. The comparison between the results obtained using both routes will be particularly interesting. Analytical work necessary to derive kinetic and hydrodynamic theories from simple interacting swimmers models, including stochastic terms, will be developed in parallel.

Materials Synthesis and Integration in Water Quality Monitoring Sensors

SL-DRF-18-0286

Research field : Soft matter and complex fluids
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l'Energie

Laboratoire Innovation, Chimie des Surfaces Et Nanosciences

Saclay

Contact :

Jean-Christophe GABRIEL

Starting date : 01-10-2018

Contact :

Jean-Christophe GABRIEL

CEA - DRF/IRAMIS/NIMBE/LICSEN

0438780257

Thesis supervisor :

Jean-Christophe GABRIEL

CEA - DRF/IRAMIS/NIMBE/LICSEN

0438780257

Personal web page : http://inac.cea.fr/Phocea/Pisp/index.php?nom=jean-christophe.gabriel

Laboratory link : http://iramis.cea.fr/nimbe/licsen/

More : https://www.linkedin.com/in/jcpgabriel

The present PhD subject comes in the context of two projects funded by the ANR in 2017 on the theme of Sensors for the environment (4WATER project). The water crisis is the # 1 risk for its impact on society after the "World Economic Forum" (01/2015). In the 4WATER project, the development of new low cost and multi-target matrix sensors is proposed. These MOSFETs sensitive to the different types of ions chosen, in a microelectronic approach, under the form of MOSFET transistors that are sensitive to various ions relevant to appreciate the water potability. This device will constitute a permanent and inexpensive multianalytical solution to monitor surface drinking water resources.



During the thesis work, the student will have to synthesize materials/chemicals by various synthetic methods and will have to solubilize them (ink formulations) so as to be able to perform deposition using an ink jet printer. This component will be integrated into water quality sensors and tested. Depending upon the remaining time and dynamism of the student, physico-chemical studies of the fluid complex, obtained from the synthesized materials and inks, will be performed in collaboration with partners' scientists. The student will be exposed to a multidisciplinary environment and will have to perform experiments in various fields such as inorganic chemistry, physical chemistry, micro-nanofabrication in clean rooms, nano-characterization, and electric/electronic testing. This PhD is therefore an excellent opportunity to build up a CV whether from the point of view of knowledge & knowhow acquisitions or regarding the footprint in the scientific world as well as through collaboration with an industrial partner.

Biophysical and dynamical study of chromatin conformation during genome replication

SL-DRF-18-0276

Research field : Soft matter and complex fluids
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l'Energie

Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire

Saclay

Contact :

Frédéric GOBEAUX

Patrick GUENOUN

Starting date : 01-10-2018

Contact :

Frédéric GOBEAUX

CEA - DRF/IRAMIS/NIMBE/LIONS

01 69 08 24 74

Thesis supervisor :

Patrick GUENOUN

CEA - DRF/IRAMIS/NIMBE/LIONS

01-69-08-74-33

Personal web page : http://iramis.cea.fr/Pisp/frederic.gobeaux/

Laboratory link : http://iramis.cea.fr/nimbe/lions/

The tridimensional organization of the genome and its dynamics in live cells are decisive to perform its functions. It is crucial to understand them and to identify the parameters controlling them. Current state of the art allows describing the short range (<10 nm) and long range (>250 nm) organization of chromatin conformation in the nucleus. However, there is an intermediate range (10-250 nm) where chromatin organization is difficult to apprehend. This range corresponds to the size of protein complexes that modify chromatin and harness genome replication.



We propose to monitor cell cultures during genome replication using small angle x-ray scattering. Thanks to a dedicated experimental set-up we will study chromatin conformation dynamics during genome duplication and complement this analysis with numerical simulations (molecular dynamics) so as to correlate chromatin dynamics with that of genome duplication. We will study different cell types to test the generality of our observations.



This project is a collaboration between two teams of physicists and biologists and will consist for the student to reach a dual expertise in both disciplines.

Optical measurements of dissipation and energy fluxes in turbulent flows

SL-DRF-18-0872

Research field : Soft matter and complex fluids
Location :

Service de Physique de l'Etat Condensé

Systèmes Physiques Hors-équilibre, hYdrodynamique, éNergie et compleXes

Saclay

Contact :

Sébastien AUMAÎTRE

Starting date : 01-10-2018

Contact :

Sébastien AUMAÎTRE

CEA - DRF/IRAMIS/SPEC/SPHYNX

01 69 08 74 37

Thesis supervisor :

Sébastien AUMAÎTRE

CEA - DRF/IRAMIS/SPEC/SPHYNX

01 69 08 74 37

Personal web page : http://iramis.cea.fr/Pisp/sebastien.aumaitre/

Laboratory link : http://iramis.cea.fr/spec/sphynx/

The aim of this proposal is the study of power fluctuations in turbulent flow. The usual theoretical approaches have shown that the stationarity of the flow, implying the balance of the power injected large scales with the power dissipated at small scales, constrains the power spectrum of the velocity. However, one needs to go beyond to explain the complexity and the intermittency of turbulent flow. One can consider the statistical properties of the fluctuations of powers involved in turbulent flow. Especially one can explore the correlations implied by the stationarity on the fluctuations of injected and dissipated power and theirs consequences on the structure of the flow. The challenge is to estimate the fluctuations of dissipated power resolved in time. To do so, we would like to develop an innovative optical technics implying diffusive wave spectroscopy and ultra-fast image acquisition. This technics will be complemented by usual measurement technics in order to estimate simultaneously the injected power and to probe the structure of the flow.

Dissipation, cascades and singularities in turbulence

SL-DRF-18-0272

Research field : Soft matter and complex fluids
Location :

Service de Physique de l'Etat Condensé

Systèmes Physiques Hors-équilibre, hYdrodynamique, éNergie et compleXes

Saclay

Contact :

Bérengère DUBRULLE

Starting date : 01-10-2017

Contact :

Bérengère DUBRULLE

CNRS - DRF/IRAMIS/SPEC/SPHYNX

0169087247

Thesis supervisor :

Bérengère DUBRULLE

CNRS - DRF/IRAMIS/SPEC/SPHYNX

0169087247

Personal web page : http://iramis.cea.fr/Pisp/berengere.dubrulle/index.html

Laboratory link : http://iramis.cea.fr/spec/sphynx/

Many phenomena in nature involve motion of viscous flows, which are widely believed to be described by Navier-Stokes equations (NSE). These equations are used for instance in numerical simulations of flows in astrophysics, climate or aeronautics. These equations are the cornerstones of many physical and engineering sciences, and are routinely used in numerical simulations. From a mathematical point of view, however, it is still unclear whether the Navier-Stokes equations are a well-posed problem in three dimensions, i.e. whether their solutions remain regular over sufficient large time or develop singularities.



Historically, the search for singularities in NSE was initiated by Leray who introduced the notion of weak solutions (i.e. in the sense of distribution). This notion was used to prove that the mathematical singular set has a one-dimensional Haussdorff measure equals to zero in space-time. Therefore, if these singularities exist, they must be extremely localized events in space and time. This makes their direct detection an outstanding problem. For some times, the best suggestive evidence of their existence was provided by the observation that the energy dissipation rate in turbulent flows tends to a constant at large Reynolds numbers This observation is at the core of the 1941 Kolmogorov theory of turbulence, and was interpreted by Onsager as the signature of singularities with local scaling exponent h=1/3. Later, it was conjectured that the singularities are organized into a multifractal set. Analysis of measurements of 3D numerical or 1D experimental velocity fields showed that the data are compatible with the multifractal picture, with a most probable h close to 1/3. However, this analysis could not reveal any information on the space-time statistics of (possible) singularities.



A major breakthrough was achieved when Duchon and Robert performed a detailed energy balance for weak solutions of INSE, and compute the contribution stemming from an eventual lack of smoothness. They show that it can be lumped into a single term that quantifies the "inertial" energy dissipation, i.e. the energy dissipated by non-viscous means.

The purpose of this thesis is to test these mathematical results in a numerical turbulent swirling flow to infer properties of the energy dissipation in a turbulent flow.

Thermoelectric phenomena in ionic liquids and nanofluids

SL-DRF-18-0370

Research field : Soft matter and complex fluids
Location :

Service de Physique de l'Etat Condensé

Systèmes Physiques Hors-équilibre, hYdrodynamique, éNergie et compleXes

Saclay

Contact :

Sawako NAKAMAE

Starting date : 01-10-2018

Contact :

Sawako NAKAMAE

CEA - DRF/IRAMIS/SPEC/SPHYNX

0169087538

Thesis supervisor :

Sawako NAKAMAE

CEA - DRF/IRAMIS/SPEC/SPHYNX

0169087538

Personal web page : http://iramis.cea.fr/Pisp/sawako.nakamae/

Laboratory link : http://iramis.cea.fr/spec/SPHYNX

More : https://www.magenta-h2020.eu

Self-assembled metamaterials made by block copolymers

SL-DRF-18-0245

Research field : Soft matter and complex fluids
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l'Energie

Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire

Saclay

Contact :

Patrick GUENOUN

Virginie PONSINET

Starting date : 01-10-2018

Contact :

Patrick GUENOUN

CEA - DRF/IRAMIS/NIMBE/LIONS

01-69-08-74-33

Thesis supervisor :

Virginie PONSINET

CNRS - Centre de Recherche Paul Pascal (CRPP)

+33(0)5 56 84 56 25

Personal web page : http://iramis.cea.fr/Pisp/patrick.guenoun/index.html

Laboratory link : http://iramis.cea.fr/nimbe/lions/

Metamaterials are "artificial" materials which are created to reach properties inaccessible to natural homogeneous materials. Optical properties like negative refractive indices could be achieved by an adequate structuring of materials at a scale lower than the wavelength of the light. In this PhD work, we shall obtain such a structuration by combining the self-assembly of copolymers on surfaces and the insertion of gold nanoparticles in the copolymer matrix. The copolymer matrix of copolymers provides the nanostructuration and the desired geometry thanks to microphase separation on top of the substrate whereas the gold nanoparticles presence confers the expected optical properties. This PhD thesis project in collaboration between LIONS at CEA Saclay (U. P. Saclay) and the Paul Pascal Research Center (CRPP) in Bordeaux will benefit from both environments to lead an experimental study which will consist in preparing surfaces where cylindrical or bicontinuous phases of copolymers will be directed perpendicularly to the substrate. After synthesis in the laboratory and insertion of gold nanoparticles in the structures, the optical properties of the obtained material will be measured and analyzed for modeling.

Hybrid carbon nanotube optoelectronic devices for silicon photonics

SL-DRF-18-0445

Research field : Solid state physics, surfaces and interfaces
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l'Energie

Laboratoire Innovation, Chimie des Surfaces Et Nanosciences

Saclay

Contact :

Arianna FILORAMO

Starting date : 01-10-2018

Contact :

Arianna FILORAMO

CEA - DRF/IRAMIS/NIMBE/LICSEN

01-69-08-86-35

Thesis supervisor :

Arianna FILORAMO

CEA - DRF/IRAMIS/NIMBE/LICSEN

01-69-08-86-35

Personal web page : http://iramis.cea.fr/nimbe/Phocea/Membres/Annuaire/index.php?uid=filoramo

Laboratory link : http://iramis.cea.fr/nimbe/LICSEN/

Thanks to their outstanding electrical, mechanical and chemical characteristics, carbon nanotubes have been demonstrated to be very promising building blocks for future nanoelectronic technologies. In addition, recently their optical properties have attracted more attention because of their typical fundamental optical transition in the NIR [1-2] in a frequency range of interest for the telecommunications. The idea is to combine their particular optical features, inferred by their one-dimensional character, with their assessed exceptional transport and mechanics characteristics for hybrid optoelectronics/optomechanics application [3-5]. However, before that this can be realized some fundamental studies are necessary. Here, we will consider the mechanism involved in the electroluminescence and photoconductivity: both the carrier injection and the mechanisms leading to radiative recombination are to be considered. We will perform studies onto semiconducting nanotubes that we will extract from the pristine mixture by a method based on selective polymer wrapping [6-14]. Then, hybrid opto-mecanichal integrated devices will be considered. This will be realized thanks to the expertise of the associated laboratories. CEA-LICSEN (Laboratory of Innovation in Surface Chemistry and Nanosciences) is part of the DRF (Fundamental Research Department) division of CEA and develops pioneer research in molecular electronics and surface chemistry, with specific know how in carbon nanotubes and their nanofabrication and self-assembly techniques. CEA- LETI (LCO) (Laboratoire des Capteurs Optiques et Nanophotonique) is part of the LETI at CEA Tech (Technological Research Department) division of CEA which is specialized in nanotechnologies and their applications, with specific know-how in photonic, nano-systems (NEMS) and optomechanics.





[1] S. M. Bachilo et al. Science 298, 2361 (2002) ;

[2] O’Connell M. J. et al., Science 297, 593 (2002) ;

[3] Freitag et al., NanoLetter 6, 1425 (2006) ;

[4] Mueller et al., NatureNanotech. 5, 27 (2010) ;

[5] S.Wang et al. Nano Letter 11, 23 (2011);

[6] Nish, A. et al. Nat. Nanotechnol. 2, 640 (2007) ;

[7] Chen, F. et al. Nano Lett. 7, 3013 (2007) ;

[8] Nish, A. et al. Nanotechnology 19, 095603 (2008) ;

[9] Hwang, J.-Y. et al., J. Am. Chem. Soc. 130, 3543-3553 (2008) ;

[10] Gaufrès E. et al., Appl. Phys. Lett. 96, 231105 (2010) ;

[11] Gao, J. et al. Carbon 49, 333 (2011);

[12] Tange M. et al. ACS Appl. Mater. Interfaces 4, 6458 (2012)

[13] Sarti F. et al Nano Research 9, 2478 (2016)

[14] Balestrieri M. et al Advanced Functional Materials 1702341 (2017).

Ultra low field Magnetic Resonance Imaging

SL-DRF-18-0386

Research field : Solid state physics, surfaces and interfaces
Location :

Service de Physique de l'Etat Condensé

Laboratoire Nano-Magnétisme et Oxydes

Saclay

Contact :

Claude FERMON

Starting date : 01-10-2018

Contact :

Claude FERMON

CEA - DRF/IRAMIS/SPEC/LNO

01 69 08 94 01

Thesis supervisor :

Claude FERMON

CEA - DRF/IRAMIS/SPEC/LNO

01 69 08 94 01

We have developed magnetic hybrid sensors based on the association of a superconducting loop to a micron size giant magnetoresistive sensor. These sensors will allow exploring a new field: Nuclear Magnetic Resonance and Magnetic Resonance Imaging at very low fields (of the order of a milliTesla).



A full head very low field MRI prototype has been built and has demonstrated the approach. The goal of the PhD will be firstly to participate to the installation of the system at Neurospin and implement fast acquisition schemes. In addition, a work on the next generation of magnetic sensors based on tunnel magnetic junctions will be performed to improve the signal to noise of the system.

Theoretical investigation of the magnetic anistropy of hybrid systems for molecular spintronics

SL-DRF-18-0045

Research field : Solid state physics, surfaces and interfaces
Location :

Service de Physique de l'Etat Condensé

Groupe Mésocopie Modélisation et Thermoélectricité

Saclay

Contact :

Cyrille BARRETEAU

Starting date : 01-12-2017

Contact :

Cyrille BARRETEAU

CEA - DRF/IRAMIS/SPEC/GMT

+33(0)1 69 08 38 56

Thesis supervisor :

Cyrille BARRETEAU

CEA - DRF/IRAMIS/SPEC/GMT

+33(0)1 69 08 38 56

Personal web page : http://iramis.cea.fr/Pisp/cyrille.barreteau/

Laboratory link : http://iramis.cea.fr/spec/GMT/

Nanomagnetism is an active field at the frontier of various domains. It consists in the study (and use) of the magnetism of nanometer sized systems. Magnetic properties of nano-objects generally strongly differ from their bulk counterpart. A major issue is to control/manipulate their magnetic properties. One of the fundamental properties of magnetic materials is their magnetic anisotropy which is characterized by their easy axis but also anisotropic magnetoresistance (AMR). It has been recently demonstrated that the interaction between a magnetic thin film and adsorbed molecules can greatly modify the anisotropy of the film due to hybridization between the molecule and the surface atoms of the substrate. Recent experiments have also shown that large AMR can be achieved in “simple” systems such as nano-conctrictions of nickel connected via a benzene molecule.

In this internship we propose to study via electronic structure methods (ab-initio and/or tight-binding) the magnetic anisotropy of few simple systems. We will first consider cobalt and iron thin films in interaction with simple molecules. More complex systems will be further investigated. The final goal is to find systems molecule/substrate with optimal properties in view of possible applications.

Lab on chip magnetoresistive biosensors for early and fast diagnosis

SL-DRF-18-0766

Research field : Solid state physics, surfaces and interfaces
Location :

Service de Physique de l'Etat Condensé

Laboratoire Nano-Magnétisme et Oxydes

Saclay

Contact :

Guenaelle Jasmin-Lebras

Claude FERMON

Starting date : 01-10-2018

Contact :

Guenaelle Jasmin-Lebras

CEA - DRF/IRAMIS/SPEC/LNO

01 69 08 65 35

Thesis supervisor :

Claude FERMON

CEA - DRF/IRAMIS/SPEC/LNO

01 69 08 94 01

Personal web page : http://iramis.cea.fr/Pisp/guenaelle.jasmin-lebras/

Laboratory link : http://iramis.cea.fr/spec/LNO/

The development of technology of early diagnosis, at the same time fast and sensitive, allowing the detection of very small quantities of (sub) micrometric biological objects (cells, bacteria, proteins etc…) is a real challenge in the medical domain. One possible method consists to label these biological objects with magnetic particles. This feature can be combined with magnetic detection, where magnetoresistive sensors, developed in our lab (LNO) to measure very low magnetic signals, can be integrated within microfluidic channels to detect these magnetically labelled biological objects.

During this PhD, the student will optimize the current lab on chip to increase the efficiency of the tests and to detect very small biological objet like bacteria and proteins . He will use the cleaning room technicals to make the GMR sensors and the microfluidic channels. He will adapt the electronic and the microfluidic parameters to optimize the signal noise ratio (SNR). In collaboration with the LERI (DRF/JOLIOT/SPI) specialized for several years in the development of fast tests of detection, he will functionalize magnetic particles with various antibodies managed against various biological objects

All oxide magnetic junctions

SL-DRF-18-0643

Research field : Solid state physics, surfaces and interfaces
Location :

Service de Physique de l'Etat Condensé

Laboratoire Nano-Magnétisme et Oxydes

Saclay

Contact :

Aurélie Solignac

Thomas Maroutian

Starting date : 01-10-2018

Contact :

Aurélie Solignac

CEA - DRF/IRAMIS/SPEC/LNO

01 69 08 95 40

Thesis supervisor :

Thomas Maroutian

Université Paris Sud - Centre de Nanosciences et de Nanotechnologies (C2N)

01 69 15 78 38

Personal web page : http://iramis.cea.fr/spec/Pisp/aurelie.solignac/

Laboratory link : http://iramis.cea.fr/spec/LNO/

Ab initio study of electronic properties of Calcium Oxalate

SL-DRF-18-0461

Research field : Solid state physics, surfaces and interfaces
Location :

Laboratoire des Solides Irradiés

Laboratoire des Solides Irradiés

Saclay

Contact :

Francesco SOTTILE

Starting date : 01-10-2018

Contact :

Francesco SOTTILE

Ecole Polytechnique - UMR 7642

0169334549

Thesis supervisor :

Francesco SOTTILE

Ecole Polytechnique - UMR 7642

0169334549

Personal web page : http://iramis.cea.fr/Phocea/Membres/Annuaire/index.php?uid=fsottile

Laboratory link : http://etsf.polytechnique.fr/

More : https://portail.polytechnique.edu/lsi/fr/recherche/spectroscopie-theorique

Calcium Oxalate is a chemical compound found in plants (used to detoxify from calcium excess), in human-driven procedures (like in beer brewing, when it produce the famous beerstones), and constitutes the most common compound of human kidney stones. In particularly linked to the latter application, for its evident medical interest, the scope of this PhD work is to study the structure, electronic and dielectric properties of the different flavours of calcium oxalate, from the anhydrous do the mono- di- and tri-hydrate polimorphisms.



Objectives of the work include the provision of reference optical and loss spectra for the different phases and structure, as well as the proposition of new experiments, both with X-ray (Inelastic X-ray scattering) and electrons probe (Electron Energy Loss Spectroscopy). The PhD candidate has a strong background in solid-state physics, and will work within Time-Dependent Density Functional Theory and Many-Body Perturbation Theory.

Magnetic properties of differently-shaped metal nanocrystals

SL-DRF-18-0336

Research field : Solid state physics, surfaces and interfaces
Location :

Service de Physique de l'Etat Condensé

Laboratoire d'Electronique et nanoPhotonique Organique

Saclay

Contact :

Fabien SILLY

Starting date :

Contact :

Fabien SILLY

CEA - DRF/IRAMIS/SPEC/LEPO

01 69 08 80 19

Thesis supervisor :

Fabien SILLY

CEA - DRF/IRAMIS/SPEC/LEPO

01 69 08 80 19

Personal web page : http://iramis.cea.fr/Pisp/fabien.silly/index.html

Laboratory link : http://iramis.cea.fr/spec/LEPO/

The structure and shape of metal nanocrystals govern their magnetic properties at the nanometer scale. The objective of this PhD project is to grow differently-shaped metal nanocrystal and investigate their magnetic properties. These structures will be characterized using scanning tunneling microscopy in ultra-high vacuum, spin polarized scanning tunneling spectroscopy and synchrotron spectroscopy. Theses tunable nanostructures are model candidates to study magnetism and observe new magnetic phenomena at the nanometer scale.

Generation of hot electrons of plasmonic origin: Physics and applications

SL-DRF-18-0292

Research field : Solid state physics, surfaces and interfaces
Location :

Service de Physique de l'Etat Condensé

Laboratoire d'Electronique et nanoPhotonique Organique

Saclay

Contact :

Ludovic DOUILLARD

Starting date : 01-10-2018

Contact :

Ludovic DOUILLARD

CEA - DRF/IRAMIS/SPEC/LEPO

01 69 08 36 26

Thesis supervisor :

Ludovic DOUILLARD

CEA - DRF/IRAMIS/SPEC/LEPO

01 69 08 36 26

Personal web page : http://iramis.cea.fr/Pisp/ludovic.douillard/

Laboratory link : http://iramis.cea.fr/spec/lepo/

Physics and applications of hot electrons of plasmonic origin



At small scale, the interaction of light with a metal object results in the occurrence of remarkable resonances within the absorption spectrum, the plasmon resonances. These resonances correspond to collective oscillations of the charge carriers [Mie 1908] and constitute a research domain in itself known as Plasmonic. Beyond its interest in the manipulation of the near optical field, a metal object at plasmonic resonance is a source of hot electrons whose electronic properties can be used to achieve non classical chemistry reactions at the local scale.



This work aims to study the fundamental physics of the emission of hot electrons by a nanometric metal object in connection with applications, particularly medical ones such as the anticancer photodynamic therapies. It is a work of experimental character in close collaboration to a relevant partnership of physicists, chemists, biologists and oncologists from different Institutions (CEA, CentraleSupélec, Saint-Louis Hospital). It will benefit from the experience acquired by the CEA IRAMIS SPEC group in LEEM / PEEM (Low Energy Electron / PhotoEmission Electron Microscopy) microscopies, the principle of which is based directly on the acquisition of the distribution of the photoelectrons emitted in response to a plasmon resonance decay [Douillard 2012, 2011] and is therefore a unique technique of choice for this study.



The objectives are to answer fundamental questions related to the emission of hot electrons by a metal particle under ultrafast multiphoton optical excitation. In particular, this involves determining the emission dynamics of the charge carriers (pump probe experiment) and their physical distributions : spatial mapping of the emission hot spots at the nano-object scale and energy mapping through the determination of the kinetic energy spectra. The ultimate goal takes place in the context of a project devoted to medical oncology and more specifically on the optimization of anticancer therapies under development, namely the photothermal and photodynamic therapies.



Keywords: hot electrons, plasmon, laser, PEEM, LEEM



[Mie 1908] G. Mie, Ann. Phys. (Leipzig) 25 (1908) 377

[Douillard 2012, 11] C. Awada, et al. J. of Phys. Chem. C 16 (2012) 14591 DOI 10.1021/jp303475c, L. Douillard, F. Charra. J. of Phys. D: Applied Physics 44 (2011) 464002 DOI:10.1088/0022-3727/44/46/464002, C. Hrelescu, et al. Nano Lett. 11 (2011) 402–407 DOI: 10.1021/nl103007m



Laboratoire d’accueil CEA IRAMIS SPEC UMR 3680

Correspondant CEA chargé du suivi de la thèse ludovic.douillard@cea.fr

Ecole doctorale Ondes et Matière, Univ. Paris Saclay.

Characterization of the interface electronic structure of ultra-thin ferroelectric HfZrO2 films for low power, CMOS-compatible, non-volatile memories

SL-DRF-18-0824

Research field : Solid state physics, surfaces and interfaces
Location :

Service de Physique de l'Etat Condensé

Laboratoire d'Etude des NanoStructures et Imagerie de Surface

Saclay

Contact :

Claire Mathieu

Nicholas BARRETT

Starting date : 01-10-2018

Contact :

Claire Mathieu

CEA - DRF/IRAMIS/SPEC/LENSIS

+33 1 69 08 47 27

Thesis supervisor :

Nicholas BARRETT

CEA - DRF/IRAMIS/SPEC/LENSIS

0169083272

Personal web page : http://iramis.cea.fr/Pisp/claire.mathieu/

Laboratory link : http://iramis.cea.fr/spec/Phocea/Vie_des_labos/Ast/ast_visu.php?id_ast=2075

The Internet of Things (IoT) requires intelligent, fast and energy efficient handling of sensory, inhomogeneous data. eFlash is the standard non-volatile memory (NVM), however, it suffers from low write speed, high power, low endurance and vulnerability to radiation.



FeRAM has the highest endurance among all NVM candidates, low energy per bit and power consumption making it a candidate to replace Flash in embedded applications.



Within the framework of the H2020 European project 3eFERRO, led by the CEA, we will use new ferroelectric HfO2-based materials to develop a competitive and versatile FeRAM technology for eNVM solutions.

The formation of an interface layer (IL) can be of crucial important to ultimate device performance and is one of the major challenges for materials engineering of FE HfO2.



Advanced characterization tools, including both soft and hard X-ray photoemission will describe the IL formation and its effect on for example band line-up, leakage and defect levels. Synchrotron radiation induced photoemission using both soft and hard X-rays will be used. Results of structural, chemistry and trap investigations will allow understanding how the defects and ILs affect the material parameters and device characteristics.

FE domain imaging in doped HfO2 and HfZrO2 will be performed using low energy and photoemission electron microscopy (LEEM and PEEM) to investigate the ferroelectricity at the nanoscale.



The thesis will require close collaboration with the partners in the 3eFERRO project. The successful candidate will participate actively in regular project meetings. The candidate will also carry out the synchrotron radiation campaigns at, for example, Soleil (Saint Aubin), Elettra (Trieste), Petra-3 (Hambourg).

Epsilon-Near-Zero modes in metamaterials for optoelectronics

SL-DRF-18-0399

Research field : Solid state physics, surfaces and interfaces
Location :

Service de Physique de l'Etat Condensé

Laboratoire d'Electronique et nanoPhotonique Organique

Saclay

Contact :

Simon VASSANT

Starting date : 01-10-2018

Contact :

Simon VASSANT

CEA - DRF/IRAMIS/SPEC/LEPO

+33 169 089 597

Thesis supervisor :

Simon VASSANT

CEA - DRF/IRAMIS/SPEC/LEPO

+33 169 089 597

Personal web page : http://iramis.cea.fr/Pisp/simon.vassant/index.php

Laboratory link : http://iramis.cea.fr/spec/LEPO/

Our team has already demonstrated theoretically and experimentally the interest of specific electromagnetic modes (epsilon-near-zero modes) for optoelectronics. These modes allow the confinement of light in a layer of sub-wavelength thickness (less than the penetration depth of the light), and thus maximize the interaction between photon and the matter.



The subject of PhD deals with the design, realization and characterization of artificial materials (metamaterials) to realize and control these electromagnetic modes.



Two approaches will be considered:

- The first is based on quantum cascade detector concepts, in partnership with C2N, ONERA, the Institut d'Optique and the 3-5 Lab (Thalès) as part of an ANR project funded from 2018 to 2022.

- The second, more exploratory, proposes to use supra-molecular assemblies on graphene. This technique is at the heart of the laboratory's expertise.



The doctoral student will have to model the structures to be created (using available numerical codes), then will have to manufacture and characterize the samples made. Part of the manufacturing will be done in clean room.

Highly spin-polarized electron transport in organic molecule-based magnetic junctions

SL-DRF-18-0443

Research field : Solid state physics, surfaces and interfaces
Location :

Service de Physique de l'Etat Condensé

Groupe Mésocopie Modélisation et Thermoélectricité

Saclay

Contact :

Alexander SMOGUNOV

Starting date : 01-05-2018

Contact :

Alexander SMOGUNOV

CEA - DRF/IRAMIS/SPEC/GMT

0169083032

Thesis supervisor :

Alexander SMOGUNOV

CEA - DRF/IRAMIS/SPEC/GMT

0169083032

Personal web page : http://iramis.cea.fr/Pisp/alexander.smogunov/

Laboratory link : http://iramis.cea.fr/spec/GMT/

We propose to study theoretically spin-polarized electron transport in tunnel junctions made of organic molecules connecting two ferromagnetic electrodes – the subject of great interest in the field of organic/molecular spintronics [1]. The particular stress will be made on the possibility to optimize and to control the degree of spin-polarization of electric current and the magnetoresistance of a junction – very important properties in spintronics – by a clever choice of molecules themselves or by some external stimuli such as a temperature (via interaction of electrons with molecule vibrations), an electric field (a gate), or a mechanical strain exerted on the molecule by electrodes. We will especially exploit a symmetry aspect of electronic orbitals of a molecule – the idea which we have recently proposed [2] – which can allow to spin-filter the electric current in the most efficient way. The combination of ab initio DFT (Density Functional Theory) electronic structure methods, as implemented in the Quantum ESPRESSO (QE) package [3], with model electron transport calculations, based on the Keldysh formalism, will be used during the project. Various new functionalities and features such as, for example, an electron-phonon coupling at the molecule or a thermal transport, will be implemented in both QE and electron transport codes.



[1] A. R. Rocha et al., Towards molecular spintronics, Nature Mater. 4, 335(2005); S. Sanvito,

Molecular spintronics, Chem. Soc. Rev. 40, 3336 (2011); V. Alek Dediu et al., Spin routes in

organic semiconductors, Nature Mater. 8, 707 (2009);

[2] A. Smogunov and Y. J. Dappe, Symmetry-Derived Half-Metallicity in Atomic and Molecular

Junctions, Nano Lett. 15, 3552 (2015);

[3] P. Giannozzi et al., QUANTUM ESPRESSO: a modular and open-source software project for

quantum simulations of materials, Phys.: Condens. Matter 21, 395502 (2009).

Theoretical description of non-linear processes in magnetic materials

SL-DRF-18-0364

Research field : Solid state physics, surfaces and interfaces
Location :

Laboratoire des Solides Irradiés

Laboratoire des Solides Irradiés

Saclay

Contact :

Valérie VENIARD

Starting date : 01-10-2018

Contact :

Valérie VENIARD

CNRS - LSI/Laboratoire des Solides Irradiés

01 69 33 45 52

Thesis supervisor :

Valérie VENIARD

CNRS - LSI/Laboratoire des Solides Irradiés

01 69 33 45 52

Personal web page : http://etsf.polytechnique.fr/People/Valerie

Second harmonic generation (SHG) is a process where two photons are absorbed by a material and a photon of twice the energy of the incoming photons is emitted. This spectroscopy is used to study the optical properties of materials because it reveals additional information, compared with linear optical spectroscopies.



Due to dipole selection rules, SHG is forbidden in centro-symmetric materials and it is possible to obtain a structural and electronic characterization for these systems. However the absence of time-inversion symmetry in antiferromagnetic materials leads to new contributions in second harmonic generation, thus revealing the arrangement of spins in the solid. SHG becomes a powerful tool to study of ultra-fast demagnetization processes.



There are few satisfactory theoretical descriptions for SHG in magnetic materials, since spin-orbit coupling, electron-electron interactions and local field effect must be treated on the same footing. To study this process, we have developed a formalism within the framework of Density Functional Theory (DFT). In this thesis, we will focus on the electron-electron interaction, described by an exchange-correlation kernel fxc which must be approximated. We will explicitly deal with spin-orbit coupling, describing electronic orbitals by a 2D spinor. We will study these effects for a typical antiferromagnetic material, namely Cr2O3.

Atomistic modelleing of the growth of III-V nitride alloys for high power high frequency components

SL-DRF-18-0740

Research field : Solid state physics, surfaces and interfaces
Location :

Centre de recherche sur les Ions, les Matériaux et la Photonique

Centre de recherche sur les Ions, les Matériaux et la Photonique

Saclay

Contact :

Jun CHEN

Starting date : 01-10-2018

Contact :

Jun CHEN

Université de Caen - CIMAP - Centre de Recherche sur les Ions, les Matériaux et la Photonique

02 33 80 85 21

Thesis supervisor :

Jun CHEN

Université de Caen - CIMAP - Centre de Recherche sur les Ions, les Matériaux et la Photonique

02 33 80 85 21

Personal web page : http://cimap.ensicaen.fr/spip.php?article204

Laboratory link : http://cimap.ensicaen.fr/spip.php?rubrique99

More : http://cimap.ensicaen.fr/

The wurtzite III-V nitride semiconductors (Al, Ga, In)N exhibit important physical properties, indeed, their band gap alloys to cover wavelengths from deep ultraviolet to near infrared, moreover, they have a ceramic character, which a high mechanical and thermal stability. Therefore, they are at the basis of electronic components that may also be used in harsh environments. For the fabrication of optimized high power, high frequency transistors, InAlN barrier have been forecast to constitute the best candidate, however obtaining highest quality layers still constitutes a challenge. In this scope, the topic of the proposed PhD research is to model the growth of such alloys using atomistic modelling through molecular dynamics. The developed tools will be integrated within our existing multiscale system for the investigation of materials properties. This theoretical work will be completed by extensive investigations of the alloys by transmission electron microscopy in close collaboration with industrial partners who carry out the growth optimization for these materials.

Molecular dynamics simulations of amorphous phase separated glasses

SL-DRF-18-0877

Research field : Solid state physics, surfaces and interfaces
Location :

Service de Physique de l'Etat Condensé

Systèmes Physiques Hors-équilibre, hYdrodynamique, éNergie et compleXes

Saclay

Contact :

Cindy ROUNTREE

Starting date : 01-10-2018

Contact :

Cindy ROUNTREE

CEA - DRF/IRAMIS/SPEC/SPHYNX

+33 1 69 08 26 55

Thesis supervisor :

Cindy ROUNTREE

CEA - DRF/IRAMIS/SPEC/SPHYNX

+33 1 69 08 26 55

Personal web page : http://iramis.cea.fr/Pisp/cindy.rountree/

Laboratory link : http://iramis.cea.fr/spec/SPHYNX/

More : http://iramis.cea.fr/spec/index.php

ToughGlasses is a fundamental research project motivated by the need to improve and assess glasses mechanical durability over the long term. Glasses are integral parts our daily lives (buildings, cars, dishes…) along with being integral parts of heat resistant technologies, protection panels (smart phones, plasma screens…), low-carbon energies (protection for solar panels) and satellites in outer space to name a few. These systems and others undergo a variety of damage (consumer use, sand storms, external irradiations, high temperatures…) which can lead to premature failure and/or alterations of the physical and mechanical properties. Frequently, post-mortem failure studies reveal material flaws, which were propagating via Stress Corrosion Cracking (SCC). A recent question arriving in the field has been: Can the Amorphous Phase Separation (APS) of SiO_2-B_2 O_3-Na_2 O (SBN) glasses provide the necessary structure to enhanced SCC behavior? This thesis project aim is to fill this gap and to unravel the structural secrets behind enhanced SCC behavior.



The Ph.D. candidate will use Molecular Dynamics simulations to study the physical, mechanical and fracture properties of APS glasses. The primary objective of this study will be to use MD simulations to characterize the structure and failure properties of APS glasses and link these to experimental SCC studies. Hence, providing information on how the intrinsic structure of the glasses plays a role on the fracture properties of APS glasses. This method of comparing and contrasting MD simulations and stress corrosion cracking experiments has been used several times within our group to reach novel understandings of the process zone size versus the crack front velocity in pure silica (SiO2) and several SBN samples. Repeating this study for SBN APS glasses compositions will aid in the understanding of how the physical structure of glasses alters the mechanical properties.



In parallel, a second thesis student will conducting experimental studies (e.g. examining physical, mechanical and fracture properties) on the same materials. Both thesis students will work together in comparing and contrasting experimental and simulation results. Thus, researchers and developers will have a better idea of how small scale structural changes scale up to devise failures.



Logistically, the candidate will be advised by C. L. Rountree at CEA, SPEC. Simulations will be carried out on local HPC computers and eventually on large-scale HPC computers. The development of methods to form APS glasses will be part of the doctoral candidate’s tasks. Results concerning the structural formation of APS glasses will be compared and contrasted with thermodynamic results gathered from CALPHAD methods. In conclusion, the theme of this project is a comprehension of the source of the changes in the macroscopic property, and in particular how to control the stress corrosion cracking properties by varying the structure of glasses through Amorphous Phase Separation.

New electronic states in single crystals and thin films of iridates

SL-DRF-18-0419

Research field : Solid state physics, surfaces and interfaces
Location :

Service de Physique de l'Etat Condensé

Laboratoire Nano-Magnétisme et Oxydes

Saclay

Contact :

Jean-Baptiste MOUSSY

Dorothée COLSON

Starting date : 01-10-2018

Contact :

Jean-Baptiste MOUSSY

CEA - DRF/IRAMIS/SPEC/LNO

01-69-08-92-00

Thesis supervisor :

Dorothée COLSON

CEA - DRF/IRAMIS/SPEC/LNO

01 69 08 73 14

Personal web page : http://iramis.cea.fr/spec/Pisp/jean-baptiste.moussy/

Laboratory link : http://iramis.cea.fr/spec/LNO/

More : http://iramis.cea.fr/spec/Pisp/dorothee.colson/

Iridates (e.g. Sr2IrO4, Sr3Ir2O7 ...) have recently attracted attention due to the presence of a strong spin-orbit coupling and strong electronic interactions that give rise to original physical properties such as, the high critical temperature superconductivity or the state of topological insulator (insulator with metallic surface states). Especially, the identification of a topological phase in these oxides should allow exploring new ways to manipulate the spin of electrons, a key point for applications in spintronics.



The aim of this thesis project is to study the emergence of Mott insulators, magnetic and topological properties in single crystals, single layers and heterostructures of iridates. More precisely, the objectives of the thesis will be to synthesize new compounds of the iridates family (e.g.Sr3Ir2O7) in the form of single crystals and thin films to explore their electronic properties (new topological phases, new Mott insulators, etc).



For the development of single crystals, the self-flux method will be chosen. Sr3Ir2O7 crystals of pure compound will be synthesized and electron doping will be achieved through cationic substitutions (for example: Sr/La). Then, the crystals will be characterized by different techniques: X-ray diffraction, electron microprobe and magnetic measurements (SQUID, VSM magnetometry). For thin films, we will use a new ultrahigh vacuum growth technique developed in the laboratory: the pulsed laser deposition (PLD) method with a laser beamworking in the nanosecond or femtosecond regime. PLD is a well-known technique for the epitaxial growth of oxide thin films (cuprates, manganites, ferrites ...), which is based on the ablation by a laser beam of the target of the material to be deposited on a monocrystalline substrate.



A peculiar attention will be given to the structural and physical properties of oxide thin films by using in situ electron diffraction (RHEED), photoemission spectroscopy (XPS/UPS), or ex situ techniques such as near-field microscopy (AFM), magnetism (SQUID,VSM).



The electronic properties of samples (crystals and films) will then be studied in collaboration with the LPS-Orsay, including electrical measurements and the quantum spin Hall effect, which is the signature of a topological state.

Thermal approach of liquid/solid and liquid/air interfaces

SL-DRF-18-0782

Research field : Solid state physics, surfaces and interfaces
Location :

Laboratoire Léon Brillouin

Groupe de Diffusion Neutron Petits Angles

Saclay

Contact :

Laurence NOIREZ

Starting date : 01-09-2018

Contact :

Laurence NOIREZ

CNRS-UMR 12 - LLB01/Laboratoire de Diffusion Neutronique

01 69 08 63 00

Thesis supervisor :

Laurence NOIREZ

CNRS-UMR 12 - LLB01/Laboratoire de Diffusion Neutronique

01 69 08 63 00

Personal web page : http://iramis.cea.fr/Pisp/laurence.noirez/

Laboratory link : http://www-llb.cea.fr/

This experimental PhD training is proposed in the frame of a collaborative program CEA-Pays de la Loire Region. The aim is to propose a new physical and physico-chemistry approach of solid / liquid or liquid / air interfacial mechanisms. At the interface of a liquid and a solid, the imbalance between the inter-molecular energies and the surface energies (attractive and repulsive) creates an intermediate zone where the liquid-liquid and liquid-solid interactions are in competition. While the literature on the subject are abundant and the developments continuously increasing, the interfacial mechanisms involved are still obscure. In particular the questions around the thermal interfacial properties are now emerging being at the heart of modern electronic devices. Pioneering experiments conducted in collaboration between the Léon Brillouin Laboratory and the Institute of Molecules and Materials of Le Mans have recently shown that, when approaching the liquid / solid interface, a variation in temperature is observable [1]. The temperature variation depends on the nature of the solid and the liquid in contact. This major discovery is a new field of investigation for the understanding of energy transfer mechanisms. It can lead to the development of passive energy converters and new technological solutions

In the frame of the PhD training it will be proposed to explore the characteristics of this novel interfacial property, its potentialities and locks. A bottom-up strategy is adopted consisting in describing how the first liquid molecules interact with the atoms of the solid in the case of high or low energy surfaces and how the energy is transferred from solid to far in the liquid. Model surfaces of different topography and of varied surface chemistry will be defined and used in order to control and characterize the surface forces (electrical, ionic or acid-base). Modern techniques of thermal analysis and of surface Raman micro-spectrometry combined with chemometric techniques will be used jointly to experimentally highlight the interfacial phenomena at several lengthscales. The candidate will also benefit of established international collaborations with worldwide leading individuals in modelling of soft matter properties from molecular up to mesoscopic and macroscopic scales. Rapid progress in understanding the mechanisms governing thermal equilibria is expected.

This program will be suitable for a student with solid skills in liquid physics, physico-chemistry of polymers or materials with a strong motivation for original experimental approaches to liquids, an interest in instrumentation and the use of Large Instruments (LLB, Soleil, ESRF) for scattering techniques.

1. L. Noirez, P. Baroni, J.F. Bardeau, Appl. Phys. Lett. 110 (2017) 213904.

2. L. Noirez, P. Baroni, J. Colloid and Surface, in press 2018.



Development of density functionals for observables

SL-DRF-18-0478

Research field : Solid state physics, surfaces and interfaces
Location :

Laboratoire des Solides Irradiés

Laboratoire des Solides Irradiés

Saclay

Contact :

Lucia REINING

Starting date : 01-10-2018

Contact :

Lucia REINING

CNRS - LSI/Laboratoire des Solides Irradiés

0169334553

Thesis supervisor :

Lucia REINING

CNRS - LSI/Laboratoire des Solides Irradiés

0169334553

Personal web page : http://iramis.cea.fr/Phocea/Membres/Annuaire/index.php?uid=lreining

Laboratory link : http://etsf.polytechnique.fr

Density Functional Theory (DFT) [1] tells us that the external potential, and therefore all observables, are functionals of the ground state density. The exact functionals are of course not known, and much effort goes into the design of suitable approximations. However, these are mostly limited to functionals for the total energy, and other observables are usually approximated by using a single Kohn-Sham Slater determinant [2] instead of the many-body ground-state wave function.



Here we are exploring possibilities to build density functionals that would directly yield observables. The main ingredients of our approach are an inversion of the diagrammatic expansion of many-body perturbation theory, and the design of a “connector” that allows us to profit from calculations which are performed once and forever in a model system [3,4]. We have already shown that using the connector idea we can describe many-body effects that go beyond the capabilities of usual DFT approximations, such as double-plasmon excitations in loss spectroscopies. If successful, besides its intellectual interest this strategy might have a strong impact in the field of materials design.



This thesis will combine conceptual, analytical and numerical work. Since it is based on a new strategy, we expect to obtain important results even without setting up a very complicated framework.





[1] W. Kohn, "Nobel Lecture: Electronic structure of matter - wave functions and density functionals", Rev. Mod. Phys. 71, 1253 (1999).

[2] W. Kohn and L. J. Sham, "Self-Consistent Equations Including Exchange and Correlation Effects", Phys. Rev. 140, A 1133 (1965)

[3] M. Vanzini, L. Reining, and M. Gatti, “Dynamical local connector approximation for electron addition and removal spectra”, arXiv:1708.02450

[4] M. Panholzer, M. Gatti, and L. Reining, “Non-local and non-adiabatic effects in the charge-density response of solids: a time-dependent density functional approach”, arXiv:1708.02992

Design of auxiliary systems for the calculation of observables

SL-DRF-18-0479

Research field : Solid state physics, surfaces and interfaces
Location :

Laboratoire des Solides Irradiés

Laboratoire des Solides Irradiés

Saclay

Contact :

Matteo GATTI

Starting date : 01-10-2018

Contact :

Matteo GATTI

CNRS - LSI

0169334538

Thesis supervisor :

Matteo GATTI

CNRS - LSI

0169334538

Personal web page : http://etsf.polytechnique.fr/People/Matteo

Laboratory link : http://etsf.polytechnique.fr

Density Functional Theory [1] tells us that the external potential, and therefore all observables, are functionals of the ground state density. The exact functionals, however, are not known, and one has to find approximations. Existing work mostly concentrates on the total ground state energy and on the electron density. To obtain the density, Kohn and Sham [2] have proposed the idea to use an “auxiliary system”. This is a simplified non-interacting system with a potential that is designed such that its density equals the true density of the real system. Of course, also this effective potential has to be approximated, and much research effort goes into finding better and better Kohn Sham potentials. In order to access also observables other than the density, we have proposed [3] to generalize the Kohn-Sham idea of an auxiliary system, and we have recently shown that this is a successful strategy [4,5]. In this thesis we will try to design auxiliary systems for observables that have to date never been calculated in this way; for example, we will examine how spin degrees of freedom are folded into effective potentials that have no explicit spin dependence.



[1] W. Kohn, "Nobel Lecture: Electronic structure of matter - wave functions and density functionals", Rev. Mod. Phys. 71, 1253 (1999).

[2] W. Kohn and L. J. Sham, "Self-Consistent Equations Including Exchange and Correlation Effects", Phys. Rev. 140, A 1133 (1965)

[3] M. Gatti, V. Olevano, L. Reining, and I. V. Tokatly, “Transforming Nonlocality into a Frequency Dependence: A Shortcut to Spectroscopy”, Phys. Rev. Lett. 99, 057401 (2007)

[4] M. Vanzini, L. Reining, and M. Gatti, “Dynamical local connector approximation for electron addition and removal spectra”, arXiv:1708.02450

[5] M. Panholzer, M. Gatti, and L. Reining, “Non-local and non-adiabatic effects in the charge-density response of solids: a time-dependent density functional approach”, arXiv:1708.02992

Exploring spin fluctuations in photosensitive molecules

SL-DRF-18-0416

Research field : Solid state physics, surfaces and interfaces
Location :

Laboratoire Léon Brillouin

Groupe Interfaces et Matériaux

Saclay

Contact :

Gregory CHABOUSSANT

Starting date : 01-10-2018

Contact :

Gregory CHABOUSSANT

CNRS-UMR 12 - LLB - Laboratoire de Diffusion Neutronique

01 69 08 96 51

Thesis supervisor :

Gregory CHABOUSSANT

CNRS-UMR 12 - LLB - Laboratoire de Diffusion Neutronique

01 69 08 96 51

Personal web page : http://iramis.cea.fr/Pisp/gregory.chaboussant/

Laboratory link : http://www-llb.cea.fr/

In the general framework of nanomagnetism, this research subject deals with fundamental properties of new magnetic materials (molecular magnetic clusters, magnetic nanoparticles) displaying very interesting functional properties like photo-commutation or the precise control of magnetization at the molecular level (data storage).



These “switchable” molecular solids are promising materials for high-density optical memory devices. Molecular materials with so-called “spin transition” properties are capable to drastically change their magnetic state upon temperature variation or under light radiation (photomagnetism). This transition is induced by an electronic state conversion of the magnetic atoms (from low-spin to high-spin state).



We have undertaken study using Small Angle Neutron Scattering (SANS) to probe structural and magnetic properties of coordination nanoparticles (CNPS’s) which are novel systems that open new possibilities for the design of molecule-based bistable objects where magnetism may be controlled or tuned by an external perturbation (light, temperature, field, etc.). Neutron scattering experiments will be carried out at the LLB neutron source (CEA Saclay, south of Paris) and/or at the Institute Laue-Langevin (Grenoble).

Ab initio simulations of spin polarized STM images

SL-DRF-18-0886

Research field : Solid state physics, surfaces and interfaces
Location :

Service de Physique de l'Etat Condensé

Groupe Mésocopie Modélisation et Thermoélectricité

Saclay

Contact :

Yannick DAPPE

Starting date : 01-10-2018

Contact :

Yannick DAPPE

CNRS - DRF/IRAMIS/SPEC/GMT

+33 (0)1 69 08 84 46

Thesis supervisor :

Yannick DAPPE

CNRS - DRF/IRAMIS/SPEC/GMT

+33 (0)1 69 08 84 46

Personal web page : http://iramis.cea.fr/Pisp/yannick.dappe/

Laboratory link : http://iramis.cea.fr/spec/GMT

Since its discovery more than 30 years ago by Binnig and Rohrer [1], the Scanning Tunnelling Microscope (STM) has become a tool of choice, not only for the study of atomic structures of surfaces or surface nanostructures, but also for the determination of the electronic properties of these systems. However, the complexity of the experimentally obtained images frequently requests an advanced theoretical support in order to reach a correct interpretation of the experimental data. In that respect, the determination of the atomic and electronic structure based on Density Functional Theory (DFT) calculations constitutes a very interesting and complementary tool for the characterization of these systems. The purpose of this PhD is to continue further the numerical developments in terms of STM images simulation by taking into account the spin polarization effects. Indeed, the study of magnetic nanostructures is of paramount importance in nowadays research due to the numerous applications in information and communication technologies. In this work, the goal will be to introduce the spin polarization in a DFT code, and then to continue the previously performed developments to determine the spin polarized current between the STM tip and the considered system. These developments will be later compared to reference experimental systems.

Superparamagnetic transitions in 3D superlattices of magnetic nanocrystals

SL-DRF-18-0451

Research field : Solid state physics, surfaces and interfaces
Location :

Service de Physique de l'Etat Condensé

Systèmes Physiques Hors-équilibre, hYdrodynamique, éNergie et compleXes

Saclay

Contact :

caroline RAEPSAET

Sawako NAKAMAE

Starting date : 01-10-2018

Contact :

caroline RAEPSAET

CEA - DRF/IRAMIS/SPEC/SPHYNX

0169082423

Thesis supervisor :

Sawako NAKAMAE

CEA - DRF/IRAMIS/SPEC/SPHYNX

0169087538

Laboratory link : https://iramis.cea.fr/spec/SPHYNX

Interactions between magnetic nanocrystals give rise to a large variety of magnetic behaviors, grouped together in a new field of physics called "supermagnetism." In this PhD project, we propose an experimental study of supermagnetic transitions; i.e., superspin glass (SSG) and dipolar superferromagnetism (SFM), in supracrystals (SC) of cobalt nanoparticles (NP) controlled by structural constraints.



We are working with 3D supracrystals, which are artificial solids which building block is not the atom but the nanoparticle. As in atomic solids, nanocrystals are organized in a specific structure such as face centered cubic (cfc) structure. The dipolar moments of nanocrystals are thus found on regular supra-lattice sites, and interact with one another through dipolar interactions. The geometric simplicity of these supracrystals offers a “real” and “simple” system that can be modelled numerically and theoretically. Supracrystal samples are prepared at the MONARIS UPMC/CNRS laboratory, with controlled NP and SC crystallinity and morphology conditions.



The proposed study concerns the experimental study of the evolution of the magnetic states of supracrystals of Co nanoparticles. Two measurements methods will be used, globally, by SQUID (Superconducting Quantum Interference Device) magnetometry and microscopically, using miniature Hall-probes. With the latter technique, we hope to detect the ferromagnetic transition in a single domain supracrystal, a decisive experimental proof of the existence dipolar SFM.



The main issue of this work concerns fundamental physico-chemistry, by evidencing the dipolar SFM in 3D superlattices. Predicted by theoretical studies, it hasn’t been observed yet. This experimental study will require a strong collaboration with the theoreticians, for interpreting the experimental results as well as validating the modelization. SFM supracrystals will find applications in the medical field, for data storage…



The competences required for the proposed study will include NP magnetism, magnetic measurements techniques (ultra-sensitive magnetometry integrating very low noise measurements), cryogenic technics, statistical analysis and experimental results interpretation. Motivated candidates will have the possibility to participate to the NP and SC synthesis, and to their structural characterization (SAXS, MET, MEB…).

ToughGlasses: Researching tomorrow’s glasses today

SL-DRF-18-0227

Research field : Solid state physics, surfaces and interfaces
Location :

Service de Physique de l'Etat Condensé

Systèmes Physiques Hors-équilibre, hYdrodynamique, éNergie et compleXes

Saclay

Contact :

Cindy ROUNTREE

Starting date : 01-10-2018

Contact :

Cindy ROUNTREE

CEA - DRF/IRAMIS/SPEC/SPHYNX

+33 1 69 08 26 55

Thesis supervisor :

Cindy ROUNTREE

CEA - DRF/IRAMIS/SPEC/SPHYNX

+33 1 69 08 26 55

Personal web page : http://iramis.cea.fr/Pisp/cindy.rountree/

Laboratory link : http://iramis.cea.fr/spec/SPHYNX/

More : http://iramis.cea.fr/spec/

The 3 years of this PhD subject are today funded by an ANR project. Decision by the laboratory over a candidature will be given early (beginning of spring 2018).



ToughGlasses is a fundamental research project motivated by the need to improve and assess glasses mechanical durability over the long term. Glasses are integral parts our daily lives (buildings, cars, dishes…) along with being integral parts of heat resistant technologies, protection panels (smart phones, plasma screens…), low-carbon energies (protection for solar panels) and satellites in outer space to name a few. These systems and others undergo a variety of damage (consumer use, sand storms, external irradiations, high temperatures…) which can lead to premature failure and/or alterations of the physical and mechanical properties. Frequently, post-mortem failure studies reveal material flaws which were propagating via Stress Corrosion Cracking (SCC). A recent question arriving in the field has been: Can the Amorphous Phase Separation (APS) of SiO2-B2O3-Na2O (SBN) glasses provide the necessary structure to enhanced SCC behavior? ToughGlasses aim is to fill this gap and to unravel the secret behind enhanced SCC behavior.



The Ph.D. candidate will have the opportunity to study the physical, mechanical and stress-corrosion cracking properties of APS glasses. The primary objective of this study will be to observe stress corrosion crack propagation in situ and the analysis of fracture surfaces in several pristine and APS glasses. Hence, providing information on environmental limit of stress corrosion cracking and understanding of how the crack growth occurs in APS glasses. This method was previously used in our group to study the process zone size versus the crack front velocity in pure silica (SiO2) and several SBN samples. Repeating this study for SBN APS glasses compositions will aid in the understanding of how the physical structure of glasses alters the mechanical properties. In conjunction with the primary objective, the candidate will have the occasion to characterize the elastic properties of the samples and their structures (Raman, NMR spectroscopy, X-ray absorption …) with various collaborators including collaborators in CEA, DEN and University of Rennes. This will allow for a comparison of the fracture behavior of glasses with other macroscopic and microscopic properties.



Logistically, the candidate will be co-advised by C. L. Rountree at CEA and F. Célarié at Université de Rennes 1. Glass formation and preliminary tests will occur at Université de Rennes 1 and stress corrosion cracking tests along with other tests will be carried out at CEA. In conclusion, the theme of this project is the comprehension of the source of the changes in the macroscopic property, and in particular how to control the stress corrosion cracking properties by varying the structure of glasses through Amorphous Phase Separation.



Some Relevant Publications:

1) “SiO2-Na2O-B2O3 density: A comparison of experiments, simulations, and theory.”

M. Barlet, A. Kerrache, J-M Delaye, and C. L. Rountree Journal of Non-Crystalline Solids. 382, 32, (2013)

2) "Hardness and Toughness of Sodium Borosilicate Glasses via Vicker's indentations”

M. Barlet, J-M. Delaye, T. Charpentier, M. Gennisson, D. Bonamy, T. Rouxel, C.L. Rountree

Journal of Non-Crystalline Solids. 417–418:66-69 (June 2015).

DOI:10.1016/j.jnoncrysol.2015.02.005

3) “Role of evaporation rate on the particle organization and crack patterns obtained by drying a colloidal layer”

K. Piroird, V. Lazarus, G. Gauthier, A. Lesaine, D. Bonamy and C. L. Rountree

Europhysics Letters, 113:38002 (February 2016).

4) “From network depolymerization to stress corrosion cracking in sodium-borosilicate glasses: Effect of the chemical composition.”

M. Barlet, J.-M. Delaye, B. Boizot, D. Bonamy, R. Caraballo, S. Peuget and C. L. Rountree

Journal of Non-Crystalline Solids. 450:174-184 (15 October 2016).

Exploration of honeycomb tellurates

SL-DRF-18-0896

Research field : Solid state physics, surfaces and interfaces
Location :

Laboratoire Léon Brillouin

Groupe Diffraction Poudres

Saclay

Contact :

Françoise DAMAY-ROWE

Starting date : 01-10-2018

Contact :

Françoise DAMAY-ROWE

CNRS-UMR 12 - LLB - Laboratoire de Diffusion Neutronique

01 69 08 49 54

Thesis supervisor :

Françoise DAMAY-ROWE

CNRS-UMR 12 - LLB - Laboratoire de Diffusion Neutronique

01 69 08 49 54

Personal web page : http://iramis.cea.fr/Pisp/francoise.damay/

Laboratory link : http://www-llb.cea.fr/

Layered honeycomb materials offer an extremely large variety of exotic magnetic behaviours, linked with the frustrated topology of the lattice, from quantum spin liquids to non colinear or dimerized magnetic orderings.



The goal of the proposed study is to study new tellurium oxides with a honeycomb structure, derived from PbSb2O6. The main challenge will be to link the crystal structure and the magnetic ground state with the observed macroscopic properties and theoretical predictions. In addition, for long-range ordered compounds, physical characterizations including dielectric properties and polarization measuresments will be carried out, in view of multiferroic applications.



The main experimental technique will be neutron scattering, which allow one to get informations on both the crystal and magnetic lattices, and on their corresponding excitations.

Characterization Electro-mechanical Control of Charged Domain Walls

SL-DRF-18-0825

Research field : Solid state physics, surfaces and interfaces
Location :

Service de Physique de l'Etat Condensé

Laboratoire d'Etude des NanoStructures et Imagerie de Surface

Saclay

Contact :

Nicholas BARRETT

Starting date : 01-10-2018

Contact :

Nicholas BARRETT

CEA - DRF/IRAMIS/SPEC/LENSIS

0169083272

Thesis supervisor :

Nicholas BARRETT

CEA - DRF/IRAMIS/SPEC/LENSIS

0169083272

Personal web page : http://iramis.cea.fr/Pisp/nick.barrett/

Laboratory link : http://iramis.cea.fr/spec/Phocea/Vie_des_labos/Ast/ast_visu.php?id_ast=2075

Ferroelectrics are insulating by nature but the recent discovery of domain wall conduction has triggered a new era for these materials: domain walls exhibit very different electronic properties and can be controlled (written or erased) under application of low power electrical fields. They are naturally nano-sized and therefore highly scalable. The conceptual breach is based here on the domain wall itself becoming the active element of the device. Under certain conditions charged domain walls can be created with true metallic conduction, orders of magnitude higher than in bulk domains through quasi 2D electron gas at the domain wall. The conductivity may be chemically or electrically controlled. The aim of the project is to realize, study and control such charged domain walls in BaTiO3 and in BiFeO3.



Tunable multicomponent supramolecular magnetic self-assembly for spintronics

SL-DRF-18-0337

Research field : Solid state physics, surfaces and interfaces
Location :

Service de Physique de l'Etat Condensé

Laboratoire d'Electronique et nanoPhotonique Organique

Saclay

Contact :

Fabien SILLY

Starting date : 01-10-2018

Contact :

Fabien SILLY

CEA - DRF/IRAMIS/SPEC/LEPO

01 69 08 80 19

Thesis supervisor :

Fabien SILLY

CEA - DRF/IRAMIS/SPEC/LEPO

01 69 08 80 19

Personal web page : http://iramis.cea.fr/Pisp/fabien.silly/index.html

Laboratory link : http://iramis.cea.fr/spec/LEPO/

The autonomous ordering and assembly of molecules on atomically well-defined surfaces is an important technique for evolving applications in nanotechnology. The objective of this PhD project is to create tunable open molecular architectures to control the ordering of magnetic nano-objects on metal surfaces. The idea is to use experimental parameters to switch to one magnetic structure to another. These structures will be characterized using scanning tunneling microscopy in ultra-high vacuum and spin polarized scanning tunneling spectroscopy. Theses tunable nanostructures are model candidates to study magnetism at the nanometer scale.

Water photo-electrolysis assisted by an internal potential

SL-DRF-18-0353

Research field : Solid state physics, surfaces and interfaces
Location :

Service de Physique de l'Etat Condensé

Laboratoire Nano-Magnétisme et Oxydes

Saclay

Contact :

Hélène MAGNAN

Antoine BARBIER

Starting date : 01-10-2017

Contact :

Hélène MAGNAN

CEA - DRF/IRAMIS/SPEC/LNO

01 69 08 94 04

Thesis supervisor :

Antoine BARBIER

CEA - DRF/IRAMIS/SPEC/LNO

01.69.08.39.23

Personal web page : http://iramis.cea.fr/Pisp/helene.magnan/

Laboratory link : http://iramis.cea.fr/spec/LNO/

More : http://iramis.cea.fr/Phocea/Vie_des_labos/Ast/ast_visu.php?id_ast=1996&id_unit=0&id_groupe=196

Photo-electrolysis is a very seductive solution to produce hydrogen using solar energy. Metal oxides are promising candidates for photoanode, but simple oxides present some limiting factors which can explain their relatively low efficiency for hydrogen production.



In this experimental thesis, we propose to use the spontaneous electric field of a ferroelectric compound to better separate photogenerated charges within the photoanode. In this study, we will investigate model samples (epitaxial thin films prepared by molecular beam epitaxy) and will study the influence of the electric polarization orientation with respect to the surface of the electrode (upward, downward, unpolarized, multi domains) on the photo-electrochemical efficiency. Moreover in order to understand the exact role of electrical polarization, we will measure the lifetime of the photogenerated charges and the electronic structure for the different state of polarization using synchrotron radiation. This thesis work is in the framework of long term research project where the CEA is associated with synchrotron SOLEIL, and University of Bourgogne for a modelisation of the systems.

In operando study of ferrite - perovskite multiferroic encapsulated microstructures

SL-DRF-18-0351

Research field : Solid state physics, surfaces and interfaces
Location :

Service de Physique de l'Etat Condensé

Laboratoire Nano-Magnétisme et Oxydes

Saclay

Contact :

Antoine BARBIER

Starting date : 01-10-2018

Contact :

Antoine BARBIER

CEA - DRF/IRAMIS/SPEC/LNO

01.69.08.39.23

Thesis supervisor :

Antoine BARBIER

CEA - DRF/IRAMIS/SPEC/LNO

01.69.08.39.23

Personal web page : http://iramis.cea.fr/Pisp/137/antoine.barbier.html

Laboratory link : http://iramis.cea.fr/spec/LNO/

More : http://iramis.cea.fr/spec/Phocea/Vie_des_labos/Ast/ast_visu.php?id_ast=2545&id_unit=9&id_groupe=179

Perovskite ferroelectric oxides coupled with magnetic ferrites belong to the new class of artificial multiferroïc materials. Their high potential for applications in spintronics and energy conversion makes their study a challenging topic. The nature of the coupling, especially during operation under an external field, remains largely unexplored. The ferrite inclusions in a single crystalline perovskite film will be realized at CEA by molecular beam epitaxy assisted by an atomic oxygen plasma or thermal treatment. The behavior of these inclusions under functioning conditions will be examined using the most advanced synchrotron radiations techniques and in particular spectro-microscopy, absorption, X-ray diffraction and magnetic dichroism, respectively on beamlines HERMES, DIFFABS and DEIMOS in a close collaborative approach. The student will acquire skills in ultra-high vacuum techniques, molecular beam epitaxy and magnetometry, as well as in the above mentioned state of the art synchrotron radiation techniques.

Theoretical study of graphene electrodes for Molecular Electronics

SL-DRF-18-0818

Research field : Solid state physics, surfaces and interfaces
Location :

Service de Physique de l'Etat Condensé

Groupe Mésocopie Modélisation et Thermoélectricité

Saclay

Contact :

Yannick DAPPE

Starting date : 01-10-2018

Contact :

Yannick DAPPE

CNRS - DRF/IRAMIS/SPEC/GMT

+33 (0)1 69 08 84 46

Thesis supervisor :

Yannick DAPPE

CNRS - DRF/IRAMIS/SPEC/GMT

+33 (0)1 69 08 84 46

Personal web page : http://iramis.cea.fr/spec/Pisp/yannick.dappe/

Laboratory link : http://iramis.cea.fr/spec/GMT/

Molecular Electronics constitute nowadays a very active field of research, either for fundamental aspects in these new systems which allow exploring new Physics at the atomic scale, than for the possible applications in terms of innovative electronic devices. Indeed, beyond the ability to reproduce silicon based components (diodes, transistors, …), molecules can also bring new types of electric response due to the great number of quantum degrees of freedom, which are tunable according to the considered molecule. Indeed, the quantum nature of these objects as well as the new associated functionalities open fascinating perspectives to build future electronics. Consequently, those new researches have led to important developments in the field of Molecular Electronics, in particular regarding the control and manipulation of electronic transport through a molecular junction. Most of the molecular junctions are based on molecules connected to metallic electrodes (gold, platinum, silver…). However, it has been demonstrated in several occasions that the connection between molecule and electrode has a non-negligible influence on the electric conductance of the system. In that manner, recent developments have proposed to make use of new materials like graphene, which is really well-known for its fantastic electric conduction properties, as electrodes for molecular junctions. Hence, it has been observed that the connection to a graphene electrode allows to significantly increase the junction conductance for long molecular chains, and therefore to reduce the energetic cost of such junction.



The main objective of this PhD lies in this frame by the theoretical study of asymmetric molecular junctions based on graphene or MoS2, as well as the study of molecular wires lifted off a surface using a STM tip. By using Density Functional Theory (DFT), we will determine the equilibrium configuration of the molecular junction and the corresponding electronic properties, before in a second time to calculate the electronic transport from the obtained structures, using a Keldysh-Green formalism. The purpose will be to understand the mechanism of conductance increase with respect to classical junctions, and to compare them to existing experimental results. The different expected behaviors in these systems allow studying the Physics of electronic transport at the atomic scale, and could be exploited for the conception of new devices at the single molecule scale.

Magnetic skyrmion dynamics in nanostructures

SL-DRF-18-0911

Research field : Solid state physics, surfaces and interfaces
Location :

Service de Physique de l'Etat Condensé

Laboratoire Nano-Magnétisme et Oxydes

Saclay

Contact :

Grégoire de Loubens

Starting date : 01-10-2018

Contact :

Grégoire de Loubens

CEA - DRF/IRAMIS/SPEC/LNO

01 69 08 71 60

Thesis supervisor :

Grégoire de Loubens

CEA - DRF/IRAMIS/SPEC/LNO

01 69 08 71 60

Personal web page : http://iramis.cea.fr/Pisp/gregoire.deloubens/

Laboratory link : http://iramis.cea.fr/spec/LNO/

More : http://www.cnrs-thales.fr/spip.php?article64&lang=fr

Magnetic skyrmions are topological singularities appearing in magnetic materials with strong Dzyaloshinskii-Moriya interaction (DMI), which favor non-colinear configurations of the magnetization. These topological objects are interesting candidates for information storage and processing, as they are naturally coupled to spintronics. Nevertheless, their stability and dynamics still have to be investigated. Recently it has been demonstrated that such structures having typical size of a few tens of nanometers could be stabilized at room temperature in nanodisks patterned from multilayers with perpendicular magnetic anisotropy and strong DMI. Their excitation spectrum has also been calculated, but never measured so far. The main objective of this thesis will thus be to experimentally probe the spin-wave excitation modes in individual nanostructures hosting single skyrmions. Another aspect will be to investigate radio frequency devices based on skyrmions, since frequency generation and detection as well as signal processing could benefit from their specific magnetization dynamics.



This thesis work will be conducted in close collaboration between the Service de Physique de l’État Condensé (CEA/CNRS) and the Unité Mixte de Physique CNRS/Thales, in the framework of the ANR project TOPSKY, which started at the end of 2017. It will be co-directed by Grégoire de Loubens (SPEC) and Vincent Cros (UMPhy).

Time resolved Spin-Charge Interconversion at Rashba Interfaces

SL-DRF-18-0953

Research field : Solid state physics, surfaces and interfaces
Location :

Service de Physique de l'Etat Condensé

Laboratoire Nano-Magnétisme et Oxydes

Saclay

Contact :

Michel VIRET

Starting date : 01-10-2018

Contact :

Michel VIRET

CEA - DSM/IRAMIS/SPEC/LNO

01 69 08 71 60

Thesis supervisor :

Michel VIRET

CEA - DSM/IRAMIS/SPEC/LNO

01 69 08 71 60

Personal web page : http://iramis.cea.fr/Pisp/michel.viret/

Laboratory link : http://iramis.cea.fr/spec/LNO/

Spintronics relies on the discrimination of spin up and down carriers originally generated by charge currents in metallic ferromagnets. Recent developments aim to get rid of this source of dissipation by manipulating pure spin currents without their charge counterpart. One convenient way of achieving this is to use the spin-orbit coupling (SOC) interaction based on the Rashba effect. This stems from the joint action of the SOC and built-in electric potentials in two-dimensional electron gases existing at surfaces, interfaces or semiconductor quantum wells. Moreover, similar physics is at play in topological insulators, materials which are insulating in the bulk but conducting at their surfaces due to broken symmetry inducing topological states.



The PhD subject proposed here will consist in measuring the spin charge conversion as spins are injected by ferromagnetic resonance and laser induced ultra-fast excitation of a ferromagnet. Both techniques are mastered in our laboratory and the latter is very promising as it can give very interesting information concerning time-resolved injection and spin lifetime with a time resolution of 100fs. The LAO/STO samples come from the University of Geneva, Bi/Ag systems are made in the university of Zaragoza while new oxide systems based on irridates are synthesized in our group by Pulsed Laser Deposition.

Failure behavior in mechanical metamaterials bone-inspired

SL-DRF-18-0887

Research field : Solid state physics, surfaces and interfaces
Location :

Service de Physique de l'Etat Condensé

Systèmes Physiques Hors-équilibre, hYdrodynamique, éNergie et compleXes

Saclay

Contact :

Daniel BONAMY

Starting date :

Contact :

Daniel BONAMY

CEA - DSM/IRAMIS/SPEC/SPHYNX

0169082114

Thesis supervisor :

Daniel BONAMY

CEA - DSM/IRAMIS/SPEC/SPHYNX

0169082114

Personal web page : http://iramis.cea.fr/Pisp/2/daniel.bonamy.html

Laboratory link : http://iramis.cea.fr/spec/SPHYNX/

The quest toward high-performance materials combining lightness and mechanical strength gave rise to a flurry of activity, driven in transport industries, for instance, driven by the desire to reduce CO2 emissions and develop fuel-efficient vehicles. In this context, the meta-materials or architectured materials offer considerable potential (e.g. micro-lattice invented at Caltech and produced by Boeing) and significant progresses have been achieved recently.



The idea explored here is to obtain a new class of materials by introducing a scale invariant (fractal) porosity inspired by the structure of bones. Special attention will also be paid at to which extend and how such a porous structure is reflected in terms of "risks", i.e. statistical fluctuations around average behavior. The final objective is to come up with rigorous rationalization tools to define one or more optima in terms of lightness, resistance to cracking, and risks (in the sense defined above) in this new class of materials.



Our previous research has provided a new formalism, at the interface between continuum mechanics and statistical physics, which permits (in simple cases) to take into account explicitly material spatial inhomogeneities and induced statistical aspects. We will seek to adapt this formalism to the case of fractal porosity. The study will rely on numerical approaches based on Random Lattice models of increasing complexity. Particular attention will be paid to a proper characterization of the statistical fluctuations around the average breaking behavior. The approach will then be confronted to experiments carried out on 2D printed samples of fractal porosity broken by means of an original experimental device developed in our laboratory and giving access to both fracture toughness and its statistical fluctuations.



This Ph.D. thesis takes place astride Statistical Physics, Continuum Mechanics and Materials Science. The candidate will have the opportunity to use, - and to familiarize himself with -, both the theoretical and experimental techniques developed in these three fields. Collaboration with the FAST laboratory in Paris-Saclay University is being currently developed. This PhD topic, combining both fundamental aspects and potential industrial applications, will permit the candidate to find job openings either in the academic field or in industry.

Ab initio simulation of transport phenomena in atomic-scale junctions

SL-DRF-18-0899

Research field : Solid state physics, surfaces and interfaces
Location :

Service de Physique de l'Etat Condensé

Groupe Mésocopie Modélisation et Thermoélectricité

Saclay

Contact :

Alexander SMOGUNOV

Starting date : 01-09-2018

Contact :

Alexander SMOGUNOV

CEA - DRF/IRAMIS/SPEC/GMT

0169083032

Thesis supervisor :

Alexander SMOGUNOV

CEA - DRF/IRAMIS/SPEC/GMT

0169083032

Personal web page : http://iramis.cea.fr/Pisp/alexander.smogunov/

Laboratory link : http://iramis.cea.fr/spec/GMT

We will develop a code for theoretical study of transport phenomena in open quantum nanosystems made of two generic macroscopic reservoirs connected by a single atomic-scale junction – the subject of great interest from both fundamental point of view but also for various technological applications.



Two macroscopic electrodes could be, for example, semi-infinite metallic (magnetic) surfaces or two-dimensional materials (such as graphene) with in-plane transport regime, while a junction could be a chain of atoms or a single (magnetic) molecule. Several transport channels across a junction, such as electron or phonon (atomic vibrations) propagation, will be treated on the same quantum-mechanical footing using Non-equilibrium Green's functions formalism [1]. The code will be based on realistic tight-binding model with parameters extracted from ab initio DFT (Density Functional Theory) calculations. The main DFT tool to be used is the Quantum ESPRESSO (QE) package [2] – one of the most accurate electronic structure codes based on plane wave expansion of electronic wave functions. Our code will be an extension of quantum transport code PWCOND [3] (which is a part of QE) to address more general transport phenomena and to treat larger scale quantum systems. It should allow, in particular, to evaluate electronic and thermal currents as a function of applied voltage or temperature gradients and thus to explore various thermoelectric phenomena. In addition, electron-electron or electron-phonon interactions inside the junction could be naturally incorporated into the model which would make possible to address also the Kondo physics or to investigate energy conversion and exchange mechanisms between electronic and phononic degrees of freedom.



[1] J. C. Cuevas and E. Scheer, Molecular Electronics: An Introduction to Theory and Experiment, World Scientific (2010)

[2] P. Giannozzi et al., QUANTUM ESPRESSO: a modular and open-source software project for quantum simulations of materials, Phys.: Condens. Matter 21, 395502 (2009)

[3] A. Smogunov, A. Dal Corso, E. Tosatti, Ballistic conductance of magnetic Co and Ni nanowires with ultrasoft pseudo-potentials, Phys. Rev. B 70, 045417 (2004)

Active matter: Coupling internal and external synchronization

SL-DRF-18-1010

Research field : Theoretical Physics
Location :

Service de Physique de l'Etat Condensé

Systèmes Physiques Hors-équilibre, hYdrodynamique, éNergie et compleXes

Saclay

Contact :

Hugues CHATE

Starting date : 01-09-2018

Contact :

Hugues CHATE

CEA - DRF/IRAMIS/SPEC/SPHYNX

0169087535

Thesis supervisor :

Hugues CHATE

CEA - DRF/IRAMIS/SPEC/SPHYNX

0169087535

Personal web page : http://iramis.cea.fr/Phocea/Membres/Annuaire/index.php?uid=chate

Laboratory link : http://iramis.cea.fr/spec/SPHYNX/

Active matter refers to the collective properties of objects transforming energy into mechanical work, most often to displace themselves. A large part of the living world is concerned (animal groups, bacteria colonies, tissues, etc.), but also, increasingly, man-made systems of various microscale swimmers, with the hope of designing new, dynamically self-organized materials or using so-called “swarm intelligence” to perform useful tasks collectively.



Collective motion is thus a central theme in active matter studies. Simple models for collective motion can be seen as systems where orientational degrees of freedom (along which particles move) try to synchronize (in which case particles move together). Many active, living, self-propelled organisms also have internal oscillatory degrees of freedom which may themselves try to synchronize upon contact and that can have, in turn, some influence on motion. This has been observed for myxobacteria, who spontaneously reverse their walk from time to time: at high densities, these reversals can synchronize, leading to collective effects in the displacement of groups.



The goal of this project is to explore the general theoretical idea of a non-trivial two-way coupling between synchronization of internal degrees of freedom and direction of motion. In this perspective, the proposed work can be classified “blue-sky statistical physics”. However, even if a fundamental, theory-driven perspective will be adopted, we foresee many relevant outcomes in the world of micro-organisms such as bacteria, but also for uncovering new modes of dynamical self-organization of man-made active particles at the micro- and nanoscale.

Synthesis of aligned carbon nanotubes on metal at low temperature: growth development and study of mechanisms

SL-DRF-18-0826

Research field : Ultra-divided matter, Physical sciences for materials
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l'Energie

Laboratoire Edifices Nanométriques

Saclay

Contact :

Emeline Charon

Martine Mayne

Starting date : 01-10-2018

Contact :

Emeline Charon

CEA - DRF/IRAMIS/NIMBE/LEDNA

0169085305

Thesis supervisor :

Martine Mayne

CEA - DRF/IRAMIS/NIMBE/LEDNA

01 69 08 48 47

Personal web page : http://iramis-i.cea.fr/Phocea/Membres/Annuaire/index.php?uid=echaron

Laboratory link : http://iramis.cea.fr/nimbe/ledna/

The CVD method (Chemical Vapour Deposition) using aerosols allows to obtain dense carpets of aligned carbon nanotubes (CNT) which applications are varied and promising. The objective of the thesis is to develop CNT synthesis at low temperature (= 650°C) according to two steps : (1) a parametric study according to the nature of carbon and catalytic precursors, and (2) a study of growth mechanisms by ex and in situ analyses.

The approach will consist of adjusting synthesis parameters (temperature, gaseous reactive atmosphere, nature of the carbon precursors or the substrate) in order to control CNT characteristics (alignment, length…). At low temperature, the decomposition of catalytic and carbonaceous precursors usually used is less effective. To solve this problem, the nature of the gaseous phase must be modified in terms of carbon precursor and carrier gas. Indeed, to limit the decrease of nanotube growth rate, it is necessary to use precursors with a more favorable catalytic and thermal decomposition around 600°C, as acetylene or ethylene or other carbon sources. Furthermore, we will perform in situ studies to characterize precisely the growth mechanisms of carbon nanotubes. A particular attention will be concerned by the control of diameter and density though electron microscopy analysis (SEM and TEM) and by the CNT structural quality analysis through Raman spectrometry and high-resolution transmission electron microscopy (HRTEM).

Curvature-induced charge separation in oxide semiconductor nanotubes: towards photocatalysis

SL-DRF-18-0439

Research field : Ultra-divided matter, Physical sciences for materials
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l'Energie

Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire

Saclay

Contact :

Sophie LE CAER

Antoine THILL

Starting date : 01-10-2018

Contact :

Sophie LE CAER

CNRS - DRF/IRAMIS/NIMBE/LIONS

01 69 08 15 58

Thesis supervisor :

Antoine THILL

CEA - DSM/IRAMIS/NIMBE/LIONS

01 69 08 99 82

Personal web page : http://iramis.cea.fr/Pisp/antoine.thill/thill_fr.html

Laboratory link : http://iramis.cea.fr/nimbe/lions/

Imogolite are natural nanotubes having a well-defined very high curvature. It is possible to produce large quantities of synthetic version of this nanomaterial thanks to the PRODIGE pilot at NIMBE. It has been recently predicted by DFT calculation that the strong curvature of the imogolite wall induces a surface density of dipole at the imogolite wall. Such radially symmetric polarization is in favour of electron/hole charge separation during photo-induced events.

In this PhD project, we propose to investigate the existence of such polarization and quantify its magnitude. Different complementary experimental strategies are proposed to reach this goal for both native and hybrid imogolite nanotubes. Iron doping of the tubes will also be tested to modulate the band gap of the nanotubes.

Bio-inspired synthetic crystals

SL-DRF-18-0435

Research field : Ultra-divided matter, Physical sciences for materials
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l'Energie

Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire

Saclay

Contact :

Corinne CHEVALLARD

Starting date : 01-11-2018

Contact :

Corinne CHEVALLARD

CEA - DRF/IRAMIS/NIMBE/LIONS

01-69-08-52-23

Thesis supervisor :

Corinne CHEVALLARD

CEA - DRF/IRAMIS/NIMBE/LIONS

01-69-08-52-23

Personal web page : http://iramis.cea.fr/Pisp/corinne.chevallard/

Laboratory link : http://iramis.cea.fr/nimbe/lions/index.php

More : http://www.fresnel.fr/spip/spip.php?article1099

Calcifying organisms (molluscs, corals, sponges) are able to produce crystallized mineral structures (shells, exoskeletons) with perfectly controlled morphology to target a particular biological function (protection, flotation, etc.). The physicochemical processes associated with this limestone biocrystallization are still poorly known. An ongoing hypothesis is that a liquid precursor could initially be formed during a liquid-liquid phase separation and then solidify as amorphous granules. These granules of size 50-500 nm would aggregate and crystallize to give the known biomineral structures, with their granularity and crystalline order at the micrometric range. In order to test such a hypothesis, the PhD student will perform calcium carbonate syntheses under biomimetic conditions, using either synthetic or biological organic additives. A detailed structural study will be performed to compare these synthetic crystals with their biogenic counterparts. The work will ultimately allow us to formulate a model of calcareous biocrystallization. It will be conducted in collaboration with the Fresnel Institute (V. Chamard, co-supervisor of this PhD thesis), and is part of a European project associating the IFREMER laboratory of French Polynesia.

Identification and characterization metrology of nanoparticles in complex systems

SL-DRF-18-0858

Research field : Ultra-divided matter, Physical sciences for materials
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l'Energie

Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire

Saclay

Contact :

Valérie GEERTSEN

Fabienne TESTARD

Starting date : 01-09-2018

Contact :

Valérie GEERTSEN

CEA - DRF/IRAMIS/NIMBE/LIONS

0169084798

Thesis supervisor :

Fabienne TESTARD

CEA - DRF/IRAMIS/NIMBE/LIONS

Personal web page : http://iramis.cea.fr/Pisp/fabienne.testard/

Laboratory link : http://iramis.cea.fr/nimbe/lions/

The statutory requirements (obligation of labeling nano ingredient in foodstuffs, cosmetic or biocides) impose on the users of "classic" additives to know if these compounds contain nanomaterials or not. With the increasing exposure to nanomaterials within the life cycle of products, it is crucial to understand their impact on the health and on the environment and thus to have reliable measures for the risk assessment.



The classical analytical methods used for molecular compounds or colloids cannot be directly transposed for nanoparticles analysis. Today, it is thus necessary to develop standard methods for characterizations of nano-objects and the associated standards. The proposed phD is in this framework of nanometrology. The objective is to estimate the performance of the existing characterization methods of nanoparticles (SAXS, DLS, DRX, MEB and AFM) and to quantify their capacity, their limits, their tolerance and their uncertainties to measure the size and shape distributions, their concentration and the roughness of surfaces. The accent will focus on the evaluation on the measurements of the influence of the environment, the size and the form of particles, as well as their cristallinity or nature of defects.



The aim is attain a new achievement with metrology for the evaluation and the characterization of nanomaterials and to estimate performance levels associated to this combination of techniques for direct measurement in complex systems. On the longer term, the coupling of these methods can be of use to the industry to make of "safer by design".

Linen analysis by R-ray microdiffraction and in-situ tensile test

SL-DRF-18-0741

Research field : Ultra-divided matter, Physical sciences for materials
Location :

Centre de recherche sur les Ions, les Matériaux et la Photonique

Centre de recherche sur les Ions, les Matériaux et la Photonique

Saclay

Contact :

Magali MORALES

Starting date : 01-10-2018

Contact :

Magali MORALES

Université de Caen - CIMAP / Centre de recherches sur les Ions, les Matériaux et la Photonique

+33 2 31 45 26 58

Thesis supervisor :

Magali MORALES

Université de Caen - CIMAP / Centre de recherches sur les Ions, les Matériaux et la Photonique

+33 2 31 45 26 58

Personal web page : http://cimap.ensicaen.fr/spip.php?article263

Laboratory link : http://cimap.ensicaen.fr/spip.php?rubrique99

The macroscopic behaviour of plant fiber reinforced polymers is strongly related to cellulose fibrillar reorganization during loading. This current assumption needs to be verified in case of flax fiber composite. The PhD student will first develops specific experimental procedures for in-situ (during tensile test) measurement of microfibrill orientation on isolated fiber, bundle of fibers, and flax composite micro-specimen. The relationships between the mechanic behavior of flax fibers at the microscopic scale and the mechanics of flax composites at the macroscopic scale will then be analyzed. The final objective of the research is to establish the mechanical micro-macro laws for plant fiber reinforced polymers. The expertise of CIMAP/PM2E team in digital image correlation, X-ray diffraction, and micro-specimen tensile test, will provide a precious input for the purpose.

Intermediate amorphous states during precipitation of cerium oxalate: towards a new nucleation model

SL-DRF-18-0111

Research field : Ultra-divided matter, Physical sciences for materials
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l'Energie

Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire

Saclay

Contact :

Sophie CHARTON

David CARRIÈRE

Starting date : 01-11-2018

Contact :

Sophie CHARTON

CEA - DEN/DMRC

+33 (0)4.66.79.62.29

Thesis supervisor :

David CARRIÈRE

CEA - DSM/IRAMIS/NIMBE

0169085489

Personal web page : http://iramis.cea.fr/Pisp/68/david.carriere.html

Laboratory link : http://iramis.cea.fr/nimbe/lions/index.php

The formation of crystals by liquid reaction takes place in the many natural and artificial processes, and in particular in reactive crystallization processes. The control of the kinetics of the formation, the size and the morphology of the precipitates is still very challenging. Size control of precipitated powder is also an important issue of nuclear fuel treatment, where plutonium is precipitated as oxalate, before being converted into the oxide used in the manufacture of MOX.

The reference theory for predicting rate of crystal formation, used in process modeling, is the classical theory of nucleation (CNT), which is based on the thermodynamic description of the liquid-vapor equilibrium proposed by Gibbs in 1876. But this model sometimes dramatically fails because it ignores all the disordered intermediate states possibly achieved between the initial solution and the final crystal: clusters, liquid-liquid phase separations, amorphous particles or networks, etc. In particular, such amorphous intermediate states were observed in the precipitation of cerium oxalate, one of the reference simulating systems for plutonium, suggesting a two-stage nucleation process in contradiction with the CNT.

The general objective of this thesis is to characterize the intermediate states of the nucleation of cerium oxalate and their impact on the predictions of classical theory. As a close collaboration between CEA Marcoule and CEA Saclay, this thesis will combine techniques known to be able to tackle this difficult problem: X-ray scattering in laboratory and synchrotron facilities (SAXS/WAXS), microfluidics, thermodynamic and kinetic models.

 

Retour en haut