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PhD subjects

60 sujets IRAMIS

Dernière mise à jour : 25-06-2019


• Analytic chemistry

• Atomic and molecular physics

• Chemistry

• Materials and applications

• Mesoscopic physics

• Optics - Laser optics - Applied optics

• Physical chemistry and electrochemistry

• Plasma physics and laser-matter interactions

• Radiation-matter interactions

• Soft matter and complex fluids

• Solid state physics, surfaces and interfaces

• Thermal energy, combustion, flows

• Ultra-divided matter, Physical sciences for materials

 

Fluidics and NMR micro-detection for real-time in situ monitoring of chemical reactions

SL-DRF-19-0791

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 :

Patrick BERTHAULT

Starting date : 01-10-2019

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. Nuclear Magnetic Resonance (NMR) can perform this task, but this requires taking into account several aspects: to overcome the lack of intrinsic sensitivity of NMR, to bring the detection zone as close as possible to the synthesis reactor and to be able to accurately quantify the data obtained.



Recently LSDRM researchers developped 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 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 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 relaxation times between each scan acquisition.



Based on CortecNet's expertise in the synthesis of stable isotope-enriched compounds, and LSDRM, a research laboratory recognized for its know-how in the creation of innovative devices for improving the NMR technique, the objective of this research project is to develop a complete NMR monitoring system, in situ, of chemical syntheses in order to provide organic chemists with an indispensable measuring instrument in their daily activities.

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

SL-DRF-19-0556

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 : 01-10-2019

Contact :

Lionel DUBOIS

CEA - DRF/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.

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

SL-DRF-19-0519

Research field : Atomic and molecular physics
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Saclay

Contact :

Valérie BRENNER

Starting date : 01-10-2019

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/

More : http://iramis.cea.fr/meetings/ESBODYR/index.php

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 and DRF/CCRT).

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

SL-DRF-19-0496

Research field : Atomic and molecular physics
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Saclay

Contact :

Michel MONS

Valérie BRENNER

Starting date : 01-10-2019

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/michel.mons/

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

More : http://iramis.cea.fr/meetings/ESBODYR/index.php

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 and DRF/CCRT) as well as from access to both the femtosecond ATTOLab server (Orme des Merisiers) and the Laser Center of the University Paris-Sud (CLUPS).

Photocatalytic deoxygenation reactions for the reduction of CO2, SO2 and N2O

SL-DRF-19-0989

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 : 01-10-2019

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/

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

The catalytic reduction of CO2, in the presence of solar irradiation, is an attractive approach to access useful chemicals, from renewable carbon and energy sources. While a narrow scope of products are currently available from the photoreduction of CO2, this doctoral project aims at producing lactones, which can serve as monomers in the preparation of polyesters, from CO2 and epoxydes. This success will rely on the developpement of efficient molecular photocatalysts and selective carbonylation catalysts able to promote a cascade where CO2 is reduced to carbon monoxide before its insertion in an epoxyde.

The knowledge derived from the design of efficient deoxygenation photocatalysts will serve as the starting point to explore a virgin research field: the deoxygenation of SO2 and N2O, two problematic gases for the environment. In particular, the photochemical reduction of SO2 to SO and the deoxygenation of N2O to N2 will be sought after.

Radiosensitive polymeric nano-objects

SL-DRF-19-0982

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

01 69 08 41 47

Thesis supervisor :

Jean-Philippe RENAULT

CEA - DRF/IRAMIS/NIMBE

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.

Synthesis and optical properties of graphene nanoparticles

SL-DRF-19-0235

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 :

Stéphane CAMPIDELLI

Starting date : 01-10-2019

Contact :

Stéphane CAMPIDELLI

CEA - DRF/IRAMIS/NIMBE/LICSEN

01-69-08-51-34

Thesis supervisor :

Stéphane CAMPIDELLI

CEA - DRF/IRAMIS/NIMBE/LICSEN

01-69-08-51-34

Personal web page : http://iramis.cea.fr/Pisp/stephane.campidelli/

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

Graphene as a constituent of graphite was close to us for almost 500 years. However, it is only in 2005 that A. Geim and K. Novoselov (Nobel Prize in 2010) reported for the first time the obtaining of a nanostructure composed by a single layer of carbon atom. The exceptional electronic properties of graphene make it a very promising material for applications in electronic and renewable energies.



For many applications, one should be able to modify and control precisely the electronic properties of graphene. In this context, we propose to synthesize chemically graphene nanoparticles and study their absorption and photoluminescence properties. This project will be developed in collaboration with Physicists so the candidate will work in a multidisciplinary environment.

Realization of efficient and innovative functionalization of graphene and carbon nanotubes for energy and material science

SL-DRF-19-0236

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 :

Stéphane CAMPIDELLI

Starting date : 01-10-2019

Contact :

Stéphane CAMPIDELLI

CEA - DRF/IRAMIS/NIMBE/LICSEN

01-69-08-51-34

Thesis supervisor :

Stéphane CAMPIDELLI

CEA - DRF/IRAMIS/NIMBE/LICSEN

01-69-08-51-34

Personal web page : http://iramis.cea.fr/Pisp/stephane.campidelli/

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

The aim of this project is the development of new functional carbon nanotubes and graphene derivatives. So far, functionalization of carbon-based nano-objects is based either on the covalent grafting or on the non-covalent adsorption of molecules on the nanotube/graphene surfaces. It is well established that the covalent grafting of molecules give rise to robust conjugates since the nano-objects and the addends are linked through covalent bonds; however, the transformation of carbon atoms hybridized sp2 into sp3 in the nanotube framework induces a sizeable loss of their electronic properties. On the contrary, the non-covalent functionalization permits to better preserve the electronic properties of the nanotubes. So, for a number of applications, the non-covalent functionalization should be preferred. However, this approach suffers from a major drawback which is the lack of stability of the resulting assemblies. Indeed, molecules adsorbed onto the nanotube sidewall can desorb, more or less easily, when for example the solvent changes or the nanotubes are filtered and redispersed.

Recently we developed a method combining most advantages of these two techniques without their major drawbacks. From the applicative point of view, this method can be used to create new carbon-based nanomaterials for photovoltaic, catalytic and electronic applications.

New generation of flexible piezogenerators

SL-DRF-19-0497

Research field : Materials and applications
Location :

Laboratoire des Solides Irradiés

Laboratoire des Solides Irradiés

Saclay

Contact :

Marie-Claude CLOCHARD

Starting date : 01-10-2019

Contact :

Marie-Claude CLOCHARD

CEA - DSM/IRAMIS/LSI/LSI

0169334526

Thesis supervisor :

Marie-Claude CLOCHARD

CEA - DSM/IRAMIS/LSI/LSI

0169334526

Personal web page : https://www.polytechnique.edu/annuaire/fr/users/marie-claude.clochard

Laboratory link : https://portail.polytechnique.edu/lsi/fr

In the framework of renewable energies, the objective of the PhD proposal is to study innovative piezoelectric systems for electricity supply.



From material point of view, the irradiation coupling of swift heavy ions (GANIL) and e-beam irradiation (SIRIUS) should enhance not only the permittivity of piezo-polymer/metal nanowires but also the elasticity of piezoelectric polymers via structural defaults such as chain scissions induced by e-beam irradiation. The flexibility of the material is a crucial parameter for the efficiency of a piezoelectric generator in order to allow the spontaneous motion of the system structure for weak flow kinetics.



From a mechanical point of view, previous works were focused on performance optimization of such systems for simple flows, meaning uniform and permanent. If the understanding of such systems under these idealized conditions is an essential preliminary step, to understand the effect of temporal and spatial variability of geophysical flows on the efficiency is a second step just as essential. In particular, winds and currents are by nature turbulent, vary at a day or a season scale, and are deeply heterogeneous in space due to the fact they interact with the geographical features. To understand the robustness of these systems performances with respect to these complexities represents a major challenge in terms of fluidic mechanics for the next years.

Microwave photon detector for single spin detection

SL-DRF-19-1030

Research field : Mesoscopic physics
Location :

Service de Physique de l'Etat Condensé

Groupe Quantronique

Saclay

Contact :

Patrice BERTET

Denis VION

Starting date : 01-09-2019

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/Phocea/Pisp/index.php?nom=patrice.bertet

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

Entangling two remote quantum systems that never interact directly is an essential primitive in quantum information science and forms the basis for the modular architecture of quantum computing. When protocols to generate these remote entangled pairs rely on using traveling single-photon states as carriers of quantum information, they can be made robust to photon losses. Today, these photon based protocols are routinely implemented in the optical domain relying on high-performance photon detectors. Transposing such protocols in the microwave domain would enable quantum information processing architecture where various moderate scale quantum computation modules are linked by lossy transmission lines on which entanglement is distributed. This quantum network architecture is one of the proposals for large scale quantum computing even if it has been so far hindered by the unavailability of low-dark count photon detectors in the microwave domain. Indeed, microwave photons have energies 5 orders of magnitude lower than optical photons, and are therefore ineffective at triggering measurable phenomena at macroscopic scales. This thesis is part of a long term research project of the Quantronics group that aims at remotely combine superconducting electrical oscillators and single crystalline defects in high quality materials in a modular architecture. The PhD thesis will aim at studying and developing high performance photon detectors based on superconducting circuits in order to provide the first demonstration of remote entanglement of a single crystalline defect with a superconducting qubit

Quantum heat transport in graphene Van der Waals heterostructures

SL-DRF-19-0966

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).

Hybrid quantum circuits coupling a single spin to a superconducting resonator

SL-DRF-19-0559

Research field : Mesoscopic physics
Location :

Service de Physique de l'Etat Condensé

Groupe Quantronique

Saclay

Contact :

Denis VION

Starting date : 01-05-2019

Contact :

Denis VION

CEA - DRF/IRAMIS/SPEC/GQ

2 5529

Thesis supervisor :

Denis VION

CEA - DRF/IRAMIS/SPEC/GQ

2 5529

This PhD thesis, in cotutelle with the Institut Quantque of the University of Sherbrooke, aims at detecting a single spin with a superconducting resonator, in two distinct cases: a qubit based on a single electron in a quantum dot on the one hand, and a single NV centre spin in diamond in the second hand.

In the first case, while the spin qubit is currently viewed as a prime candidate for quantum information processing, the currently preferred readout method is destructive. The proposed research project aims at experimentally demonstrating in The Unversity of Sherbrooke a new type of measurement based on the parametric modulation of the longitudinal coupling between a superconducting microwave resonator and the qubit.

In the second case of the NV centre, its purely inductive detection with a low impedance resonator will be developed at CEA-Paris-Saclay university.

Towards hybrid quantum computing: from superconducting circuits to nuclear spins

SL-DRF-19-0529

Research field : Mesoscopic physics
Location :

Service de Physique de l'Etat Condensé

Groupe Quantronique

Saclay

Contact :

Emmanuel FLURIN

Daniel ESTEVE

Starting date : 01-09-2019

Contact :

Emmanuel FLURIN

CEA - DRF/IRAMIS/SPEC/GQ

0622623862

Thesis supervisor :

Daniel ESTEVE

CEA - DSM/IRAMIS/SPEC/GQ

0169085529

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

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

Quantum information has emerged in past decades as a new pillar of science at the crossroad between quantum physics and information processing. In particular, quantum computation holds great promise for surpassing conventional computing at solving certain class of hard problems such as factoring large integers, searching in an unstructured database, or more realistically classifying sets, or addressing the many body problem in quantum chemistry, complex materials or nuclear physics. Quantum bits are the fundamental carriers of quantum information, and numerous condensed matter system have been shown to host degrees of freedom able to faithfully retain such quantum information, in particular in superconducting electrical oscillators or single crystalline defects in high quality materials. The PhD thesis is part of a long term research project of the Quantronics group that aims at combining precisely these two types of quantum systems in a hybrid structure: impurities trapped in solids would form high fidelity memory elements in superconducting quantum processors.

The goal of the PhD thesis will be first to optimize the coupling between the circuit and a single spin trapped in diamond and second to successfully detect the unique microwave photon generated by the de-excitation of the electron spin. This single photon will be captured by a superconducting qubit of the transmon type, a key element of the superconducting quantum processor, thus laying the foundations for a new quantum processor architecture.

Electron tunneling time and its fluctuations

SL-DRF-19-0504

Research field : Mesoscopic physics
Location :

Service de Physique de l'Etat Condensé

Groupe Nano-Electronique

Saclay

Contact :

Carles ALTIMIRAS

Patrice ROCHE

Starting date : 01-09-2019

Contact :

Carles ALTIMIRAS

CEA - DRF/IRAMIS/SPEC/GNE

01 69 08 55 29

Thesis supervisor :

Patrice ROCHE

CEA - DRF/IRAMIS/SPEC/GNE

0169087216

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

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

More : https://nanoelectronicsgroup.com/

Challenging our classical intuition, quantum tunneling has fascinated physicists for decades. Very soon after its discovery, it raised the question of how much time do particles spend under the classically forbidden barrier. Despite its simplicity, such a question is ill defined in terms of quantum observables and does not admit a single answer, thus triggering over the past decades a bunch of different definitions corresponding to different (thought) scenarios.



Following a proposal by Büttiker & collaborators [1], we will address this question from the perspective of a well-defined observable: that is, measuring the spectrum of time fluctuations of the number of particles residing within the classically forbidden barrier. The idea is to exploit semiconducting 2D electron gases where electrostatically coupled metallic gates are used to generate the electrostatic potential barrier upon which the electrons are scattered. Moreover, we will equally use them to collect the mirror influence-charges fluctuating in response to the tunneling electrons residing within the electrostatic barrier. Despite its conceptual simplicity, implementing such a scenario is a formidable task since it demands collecting a tiny radiofrequency (RF) signal emitted by a huge output-impedance source in a sub-Kelvin (dilution) refrigerator. We will build upon the group’s expertise in RF design and ultra-low noise measurements in cryogenic environments in order to overcome this challenge, notably implementing recently developed high impedance RF matching circuits [2] allowing us to efficiently collect the signal into a RF detection chain.



In a second step, we will perform similar measurements in experimental conditions where electron-electron interactions strongly modify the transport properties across the barrier. Notably a metal/insulator quantum phase transition is driven by such interactions when a 1D wire is interrupted by an impurity, mimicking Tomonaga-Lutinger liquid dynamics [3]. We wish to investigate this physics from the original perspective of the electron tunneling time, as put forward by a recent theoretical finding [4].



The student will participate to the radiofrequency design of the samples, to their fabrication in a clean-room environment, and to their measurement exploiting low noise measurement techniques both in the near DC and the few GHz range. He will become familiar with sub-Kelvin cryogenic techniques as well.



References:

[1] Pedersen, van Langen, and Büttiker, Phys. Rev. B 57, 1838 (1998)

[2] Rolland et al., https://arxiv.org/abs/1810.06217

[3] Anthore et al., Phys. Rev. X 8, 031075 (2018)

[4] Altimiras, Portier and Joyez, Phys. Rev. X 6, 031002 (2016)

Compressed sensing applied to spatio-temporal metrology of ultrashort lasers

SL-DRF-19-0604

Research field : Optics - Laser optics - Applied optics
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Physique à Haute Intensité

Saclay

Contact :

Fabien QUÉRÉ

Starting date : 01-10-2019

Contact :

Fabien QUÉRÉ

CEA - DRF/IRAMIS/LIDyL/PHI

01.69.08.10.89

Thesis supervisor :

Fabien QUÉRÉ

CEA - DRF/IRAMIS/LIDyL/PHI

01.69.08.10.89

Personal web page : http://iramis.cea.fr/Pisp/107/fabien.quere.html

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

Laser technology now makes it possible to generate coherent light pulses with durations down to a few tens of femtosecondes only, with an energy per pulse of up to several Joules. These laser beams are likely to exhibit spatio-temporal coupling, i.e. a spatial dependence of their temporal properties across the beam, which can considerably degrade their performances. Our team has developed over the last few years different techniques to measure the full spatio-temporal structure of such lasers. These advanced measurement techniques have been demonstrated on different lasers, including some for the most powerful systems in operation to date. The objectives of this PhD work will be twofold: 1- to exploit these new advanced techniques to characterize different laser sources, of increasing complexity; 2- to improve these measurement techniques, in particular by reducing the number of required laser shots. This second point will be achieved by both using the modern techniques of compressed sensing, and designing new schemes to encode the relevant information in the measured data. The ultimate goal is to obtain all information on the spatio-temporal structure of the beam in a single laser shot, in contrast to the hundreds of shots required with the present techniques.

Conformation-resolved spectroscopy of isolated ion pairs

SL-DRF-19-0868

Research field : Physical chemistry and electrochemistry
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Saclay

Contact :

Eric GLOAGUEN

Starting date : 01-09-2019

Contact :

Eric GLOAGUEN

CNRS - DSM/IRAMIS/LIDyL/SBM

01 69 08 35 82

Thesis supervisor :

Eric GLOAGUEN

CNRS - DSM/IRAMIS/LIDyL/SBM

01 69 08 35 82

Personal web page : http://iramis.cea.fr/LIDYL/Pisp/eric.gloaguen/

Laboratory link : http://iramis.cea.fr/LIDYL/Phocea/Vie_des_labos/Ast/ast_groupe.php?id_groupe=601

More : https://www.universite-paris-saclay.fr/fr/education/doctorate/chemical-sciences-molecules-materials-instrumentation-and-biosystems-2mib#concours-mesri-2019

Ion pairs are ubiquitous in Nature, from sea water and aerosols, to living organisms. The scientific program of this thesis aims at investigating, at the microscopic scale, neutral ion pairs, isolated and microsolvated in the gas phase, by using an approach combining conformer-selective IR and UV spectroscopy, molecular dynamics simulations and quantum chemistry calculations. Three directions will be explored:

- Spectroscopic characterization of each type of pairs, and application to the dissociative role of the solvent.

- Description of the first steps of crystallisation of ionic compounds.

- Analysis of the influence of counter-ions on the structure of charged biomolecules.



A CV, a motivation letter and the contacts of the Master interships supervisors must be sent before April 22nd, 2019. The selected candidate will access the MESRI 2019 Competition of the 2MIB doctoral School of Paris-Saclay University.

Investigating metal-oxygen batteries using in situ solid-state NMR spectroscopy

SL-DRF-19-0495

Research field : Physical chemistry and electrochemistry
Location :

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

Laboratoire Structure et Dynamique par Résonance Magnétique (LCF)

Saclay

Contact :

Alan WONG

Starting date : 01-10-2019

Contact :

Alan WONG

CNRS - DRF/IRAMIS/NIMBE/LSDRM

+33 1 69 08 41 05

Thesis supervisor :

Alan WONG

CNRS - DRF/IRAMIS/NIMBE/LSDRM

+33 1 69 08 41 05

Personal web page : http://iramis.cea.fr/Pisp/alan.wong/

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

More : http://iramis.cea.fr/nimbe/Pisp/magali.gauthier/

Rechargeable metal-O2 batteries have attracted much attention in recent years as a possible alternative to the widely used lithium-ion batteries. This is particularly the case for lithium and sodium-oxygen batteries, due to their potential high energy densit. However, great challenges remain in the development of M-O2 batteries and in the understanding of the underlying mechanisms taking placed inside M-O2 batteries. Clear identifications of the discharge electrochemical pathways and their products (MO2 or M2O2), as well as the reactivity of the electrolyte, are crucial. The thesis objective is to investigate the electrochemical and chemical reactions in M-O2 batteries under real-time potential cycling using recently emerged in situ solid-state NMR spectroscopy. The thesis will consist of (1) optimizing the recently developed in situ solid-state NMR facility at LSDRM for studying metal-O2 batteries; (2) understanding reaction mechanisms in M-O2 systems; and (3) exploring new routes for improving the battery performance at LEEL.

Investigation by electrochemical microscopy of the multiphase transport within composite materials of a PEMFC

SL-DRF-19-0493

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 : 01-09-2019

Contact :

Renaud CORNUT

CEA - DRF/IRAMIS/NIMBE/LICSEN

01 69 08 65 88

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-19-0512

Research field : Physical chemistry and electrochemistry
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Saclay

Contact :

Lionel POISSON

Eric GLOAGUEN

Starting date : 01-10-2019

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.

Photocatalytic nanohybrids in microfluidic chips for the recycling of carbon dioxide

SL-DRF-19-0507

Research field : Physical chemistry and electrochemistry
Location :

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

Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire

Saclay

Contact :

Florent Malloggi

Eric DORIS

Starting date : 01-09-2019

Contact :

Florent Malloggi

CEA - DSM/IRAMIS/NIMBE/LIONS

33.(0)1.69.08.23.55

Thesis supervisor :

Eric DORIS

CEA - DRF/JOLIOT/SCBM/LMT / Tritium

+33-169 08 80 71

Personal web page : http://iramis.cea.fr/Pisp/florent.malloggi/

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

Our fossil fuel based society is facing two major and interconnected problems:

i) the progressive depletion of fossil fuels, and

ii) the impact of their combustion on air pollution and global warming caused by large-scale emission of carbon dioxide (CO2).



To avoid the obvious consequences on climate changes, the concentration of such a greenhouse gas in the atmosphere must be stabilized but, as populations grow and economies develop, there is an increasing demand of fossil fuels from developing countries. The photocatalytic reduction of CO2 is considered as a highly promising strategy for the production of hydrocarbon fuels while simultaneously resolving energy crisis and greenhouse effect.



The goal of this project is to address the principles of an integrated H2O oxidation/CO2 reduction cycle, for efficient solar energy storage, and environment remediation. The ultimate target is to drive CO2 photo-reduction to liquid fuels such as methanol, methane or light hydrocarbons while using H2O as the primary, carbon-free, renewable source of reducing equivalents (e.g. electrons). This strategy goes beyond artificial photosynthesis by solar-powered water splitting yielding molecular H2. Instead, this project looks at the direct reduction of anthropo-genically produced CO2 to yield conventional hydrocarbon fuels by a renewable photocatalytic cycle.

Nanoscale electrocatalytic activity at individual carbon nanostructures

SL-DRF-19-0958

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 : 01-10-2019

Contact :

Renaud CORNUT

CEA - DRF/IRAMIS/NIMBE/LICSEN

01 69 08 65 88

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 our energy supply depends on our ability to innovate in the development of energy conversion and storage systems. In this field, electrocatalytic materials are the cornerstone of many challenges, particularly for fuel cells, as they offer the appropriate solutions to efficiently perform complex chemical reactions. The project introduces and implements a new strategy based on electrochemical microscopy and numerical simulation to find new inexpensive elementary bricks: the combined analysis of nano-objects will allow identifying new electrocatalytic species, allowing the design of more efficient devices.



Regarding the development of electrical vehicles, PEMFC (Proton Exchange Membrane Fuel Cell) is a promising and not polluting alternative to classical thermal engine. Numerous car manufacturers are developing commercial hydrogen vehicles using PEMFC but mass production requires reducing their cost by lowering the platinum (Pt) dependency.



Pt being a highly expensive metal, development of Platinum-free (Pt-free) efficient active layers is thus the major challenge for reducing cost of PEMFC.



The project involves electrochemical probe microscopy to map the electrocatalytic activity of individual catalysts particles, intrepreted thanks finite element method modelling. The focus will be on Oxygen reduction reaction catalysis in acidic media of Pt-free nanomaterials.

Analysis and modeling the evolution of new active materials during the first charge-discharge cycles of a Li-Ion battery

SL-DRF-19-0490

Research field : Physical chemistry and electrochemistry
Location :

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

Laboratoire Edifices Nanométriques

Saclay

Contact :

Benoit MATHIEU

Nathalie HERLIN

Starting date : 01-10-2018

Contact :

Benoit MATHIEU

CEA - DRT/LITEN/DEHT/LMP

04 38 78 18 44

Thesis supervisor :

Nathalie HERLIN

CEA - DRF/IRAMIS/NIMBE/LEDNA

0169083684

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

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

More : https://www.researchgate.net/profile/Benoit_Mathieu

Facing the energy transition, the storage of energy is a major issue. However, it appears necessary to increase the battery storage capacity and one way could be the use of silicon in addition to graphite for the negative electrode of Li-ion accumulators. The development of accumulators based on these materials is however slowed by their instability, related to the swelling of silicon during the insertion of lithium. Thus, the understanding of the phenomena occurring during the first cycles of operation appear fundamental to master the operation over the long term.



This thesis project aims to understand and model the mechanical behavior of these new silicon-graphite electrodes. It is based on 3 teams: in Saclay, we will synthesize custom materials: silicon nanoparticles, silicon / germanium alloys, core @ shell where the shell will be carbon. Commercial silicon / graphite materials will also be used as reference. The behavior of materials will be studied in Grenoble using a laboratory diffractometer allowing in-situ and operando analyzes and large instruments such as ESRF or SOLEIL. These measurements will provide information on the stress inside the silicon but also on the state of lithiation of the graphite and will allow the modeling of the electrochemistry of the insertion of the lithium in the silicon, in particular the dependence in time of the hysteresis, still poorly understood. The aim of the thesis is to build a physics-based battery model allowing: "simple" experiments of swelling measurements, electrical cell performance measurements, early-life and model cycling and modelization, to deduce the mechanical and electrochemical behavior of cells at the scale of grains and agglomerates. This, in order to predict the aging of cells in the long term, in relation with their mechanical properties.

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

SL-DRF-19-0689

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 : 01-10-2019

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.

SL-DRF-19-0432

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 :

Marie GELEOC

Jean-Philippe RENAULT

Starting date : 01-09-2019

Contact :

Marie GELEOC

CEA - DRF/IRAMIS/LIDyL/SBM

Thesis supervisor :

Jean-Philippe RENAULT

CEA - DRF/IRAMIS/NIMBE

01 69 08 15 50

Personal web page : http://iramis.cea.fr/Pisp/marie.geleoc/

Laboratory link : http://iramis.cea.fr/lidyl/sbm/

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

Plasma Mirrors 'on-chip': "Towards extreme intensity light sources and compact particle accelerators"

SL-DRF-19-0633

Research field : Radiation-matter interactions
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Physique à Haute Intensité

Saclay

Contact :

Henri VINCENTI

Guy BONNAUD

Starting date : 01-10-2019

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://picsar.net

Attosecond pulses generated in activeoptical gratings: experiments, theory and applications

SL-DRF-19-0487

Research field : Radiation-matter interactions
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Attophysique

Saclay

Contact :

Thierry Ruchon

Starting date : 01-10-2019

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 putting at play two beams forming an active grating to generate attosecond pulses with controlled 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.



Detailed presentation of the subject : http://iramis.cea.fr/LIDYL/Pisp/thierry.ruchon/

Quantum fragmentation in frustrated magnets

SL-DRF-19-0538

Research field : Radiation-matter interactions
Location :

Laboratoire Léon Brillouin

Groupe 3 Axes

Saclay

Contact :

SYLVAIN PETIT

ELSA LHOTEL

Starting date : 01-10-2018

Contact :

SYLVAIN PETIT

CEA - DRF/IRAMIS

01 69 08 60 39

Thesis supervisor :

ELSA LHOTEL

CNRS - Insitut Néel

04 76 88 12 63

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

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

Magnetic frustration is one of the modern routes in condensed matter physics leading to the discovery of new states of matter. The “spin ice” and more generally, the “Coulomb phases” are celebrated examples of this physics. In contrast with classical magnetically ordered phases, these states remain disordered down to the lowest temperatures, yet form a correlated paramagnet with specific spin-spin correlations. In this context, a new concept has been recently proposed, called “magnetic fragmentation” [PRX 4, 011007 (2014)]. This is an original state where the magnetic moment fragments into two sub-fragments: one of them forms an antiferromagnetic phase with a reduced ordered moment, while the other keeps fluctuating and forms a Coulomb phase.



In combining magnetization measurements, elastic and inelastic neutron scattering experiments, we have shown that the pyrochlore compound Nd2Zr2O7 could be a realization of this theory [1,2], even if experimental evidences suggest that still not understood quantum phenomena are at play.



This thesis work aims at understanding the origin of fragmentation in this system. We especially plan to determine its stability range by studying doped samples. Actually, replacing part of the Zirconium (Zr) by Titanium (Ti), or Neodymium (Nd) by Lanthanum (La), magnetic interactions can be modified. Varying the substitution, we will explore the phase diagram and probe the possible existence of a quantum critical point predicted by theory. The complementarity between macroscopic and neutron scattering measurements is one of the key points to determine the quantum Hamiltonian and beyond, understand the microscopic mechanisms of magnetic fragmentation, along with the nature of the spin dynamics that emerge from this peculiar ground state.



The thesis work will take place in France both at the Institut Néel (Grenoble) and at LLB (Saclay). It consists in measuring both the magnetization and specific heat down to base temperature (100 mK) (Institut Néel) and to finely determine the magnetic structures as well as the spin excitations spectrum by the different neutron techniques. The latter will be carried out at LLB (Saclay) and at ILL (Grenoble). A large part of the data analysis will be based on numerical simulation tools. Most of them exist today but may be further developed.

Physics and applications of hot electrons of plasmonic origin

SL-DRF-19-0347

Research field : Radiation-matter interactions
Location :

Service de Physique de l'Etat Condensé

Laboratoire d'Electronique et nanoPhotonique Organique

Saclay

Contact :

Ludovic DOUILLARD

Starting date : 01-10-2019

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/

At small scale, the interaction of light with a metallic 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 Plasmonics. 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 metallic 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, Hospital Saint-Louis). It will benefit from the experience acquired by the CEA IRAMIS SPEC group in LEEM / PEEM (Low Energy Electron / PhotoEmission Electron) 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 2017, 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 metallic 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 (breast cancer) and more specifically on the optimization of anticancer therapies under development, namely the photothermal and photodynamic therapies.



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

Irradiation effects on the infrared optical properties of ZnGeP2

SL-DRF-19-0056

Research field : Radiation-matter interactions
Location :

Laboratoire des Solides Irradiés

Laboratoire des Solides Irradiés

Saclay

Contact :

Jérémie Lefevre

Bruno BOIZOT

Starting date : 01-10-2019

Contact :

Jérémie Lefevre

Ecole Polytechnique - Laboratoire des Solides Irradiés

01 69 33 45 30

Thesis supervisor :

Bruno BOIZOT

CEA - DRF/IRAMIS/LSI/LSI

01 69 33 45 22

Personal web page : https://www.polytechnique.edu/annuaire/fr/users/bruno.boizot

Laboratory link : https://portail.polytechnique.edu/lsi/fr/recherche/defauts-desordre-et-structuration-de-la-matiere

The ZnGeP2 compound, in its monocrystalline form, is a remarkable and very promising material for infrared optical applications: it is transparent between 1 and 8 µm and, due to its positive birefringence, it has highly-effective nonlinear optical properties.



The improvement of transparency properties in the infra-red (IR) domain of this material is thus both a scientific and technical challenge. However, defects coming from the synthesis processes induce absorption bands in the IR range, thus limiting the physical properties of this compound. Irradiation could be a new way for changing the nature and the content of defects responsible of this absorption in the IR domain.



The goal of the PhD is therefore to define the irradiation conditions (fluences, beam energy, irradiation temperature ...) for improving the IR properties of irradiated ZnGeP2. For that purpose, a quantitative spectroscopic tool like Electron Paramagnetic Resonance spectroscopy will be used in order to determine the mechanisms of irradiation defects production and their interactions with the defects produced during the pulling of ZnGeP2 crystals.

Ultra relativistic plasmonic

SL-DRF-19-0725

Research field : Radiation-matter interactions
Location :

Laboratoire des Solides Irradiés

Laboratoire des Solides Irradiés

Saclay

Contact :

Michèle RAYNAUD

Starting date : 01-10-2019

Contact :

Michèle RAYNAUD

CEA - DRF/IRAMIS/LSI/LSI

Thesis supervisor :

Michèle RAYNAUD

CEA - DRF/IRAMIS/LSI/LSI

Personal web page : http://www.polytechnique.edu/annuaire/fr/users/michele.raynaud-brun

Laboratory link : https://portail.polytechnique.edu/lsi/fr/recherche/theorie-de-la-science-des-materiaux/plasmonique-lechelle-quantique

The present PHD work aims at exploring theorically and numerically the generation of fast electron beams in relativistic laser-solid interaction by using properly-structured targets whose surface characteristics allow SPW excitation or local electromagnetic modes in regimes of laser intensity ranging above 10^21 W/cm2. The “upgrading” of Relativistic Plasmonics physics toward intensity regimes of magnitude larger than the typical values used in ordinary plasmonics, and such that nonlinear and relativistic effects play a major role is of fundamental interest for the physics of relativistic plasmas. It may also lead to groundbreaking ultra-short synchronized light and electron sources with applications in probing ultrafast electronic processes. In this context, this theoretical and numerical study will allow to suggest new experimental schemes feasible on the Apollon facility and multi-PW lasers.

Irreversibility and out-of-equilibrium in turbulence

SL-DRF-19-0825

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 :

François DAVIAUD

Starting date : 01-10-2019

Contact :

François DAVIAUD

CEA - DRF/IRAMIS/SPEC/SPHYNX

01 69 08 72 40

Thesis supervisor :

François DAVIAUD

CEA - DRF/IRAMIS/SPEC/SPHYNX

01 69 08 72 40

Personal web page : http://iramis.cea.fr/Pisp/francois.daviaud

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

Turbulent flows are fundamentally out of equilibrium. They are characterized by fluxes of quantity of movement, heat or energy over a range of scales covering several orders of magnitude. The corresponding number of degrees of freedom is very large and does not allow their direct implementation on a computer. To progress, it is therefore necessary to be able to model these flows taking into account the out of equilibrium nature of turbulence.



The purpose of this thesis is to investigate the validity of the formalism of out of equilibrium physics (fluctuation-dissipation theorems, function of large deviations) in a turbulent von Karman model flow. We will try to obtain direct measurements of the velocity fields, to characterize, in the scale space, the different flows and their relationship with the forcing constraints. We will use 2D and 3D Particle Image Velocimetry measurements and a new multi-scale analysis method similar to the wavelet transform.

Reaction-ready cubosomes: a self-assembled nano-platform for multifunctional delivery

SL-DRF-19-0936

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 :

Christophe FAJOLLES

Patrick GUENOUN

Starting date : 01-11-2019

Contact :

Christophe FAJOLLES

CEA - DSM/IRAMIS/NIMBE/LIONS

01 69 08 99 60

Thesis supervisor :

Patrick GUENOUN

CEA - DRF/IRAMIS/NIMBE/LIONS

01-69-08-74-33

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

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

Cubosomes are nanometric particles formulated from lipid bicontinuous cubic phases. Water-lipid bicontinuous cubic phases [Luzzati, 1962] are made from a single continuous lipid bilayer, where the bilayer midplane is coincident with an infinite periodic minimal surface and subdivides the space into two interpenetrating, but not connected water channels [Scriven, 1976]. The large surface area of the lipid-water interface (400 m2g-1) makes these nano-objects suitable for entrapment of proteins, peptides, and other biomolecules. Also their polar-apolar continuous domains allow for the encapsulation of a broad range of hydrophilic-hydrophobic molecules and for a slow release of cargo, maintaining the therapeutic concentration range over a longer period of time. Cubosomes suffer however from limited possibilities to control load and delivery of potential cargo. The size of the water channels, one of the few available structural parameters, can only be varied in a relatively narrow size range and the chemical nature of the lipids(here monoolein named MO), defining also the lipid-water interface, cannot be significantly modified without compromising the integrity of the structure.



In this PhD project we aim at bringing the control of uptake and release in cubosomes to new possibilities by engineering reaction-ready cubosomes and achieving flexibility in cubosome functionalization by allowing for in-situ multi-dimensional orthogonal reactions combined with the power of inclusion complexation provided by cyclodextrins (CDs). In practice, standard structure-forming lipids will be functionalized to allow for orthogonal click-chemistry reactions to occur at the lipidwater interface in the channels of these lipid mazes. This will open the pathway for devising sophisticated strategies for the kinetics of charging and discharging the nanoparticles with a variety of relevant payloads.

The structure of cubosomes will be characterized by several techniques, such as small angle X-ray scattering (SAXS), cryo-electron microscopy (cryo-EM), NMR and differential scanning calorimetry (DSC) [Angelova, 2015; Li, 2015].

Despite extensive work on cubosomes, outstanding questions still hamper progress in the understanding and control of the encapsulation and release mechanisms. How many of the channels actually communicate with the solution, are all cubosomes open, what is the role of exact shape and size on the exchange processes, why are cubosomes most often decorated with single bilayer handles and what role do they play … these questions require designing advanced experimental geometries to inter-relate structure and properties. We will address them by performing kinetic experiments on single cubosomes under a fluorescence microscope. Although for many therapeutic applications cubosomes are brought into contact with cell cultures, experiments on model systems are required to assess the fundamental parameters controlling how cubosomes behave at oil/water or lipid bilayer interfaces [Falchi, 2015]. We will apply synthetic chemistry following robust pathways [Osornio, 2012] to achieve in-situ functionalization summarised. Pathways are flexible enough to accommodate efficient labelling requirements (deuterium or fluorescence)or modifications required during the course of the project such as adjusting a spacer between lipids and the desired functional groups. Functional groups are chosen to be consistent with modern ligation methods in order to allow further access to large libraries of compounds and high throughput methods. They have also to allow selective orthogonal reactions according to Sharpless click chemistry paradigm. Of particular interest, the Huisgen reaction AAC (Alkyne-azidecycloaddition), usually referred as the first click reaction, will be performed using different sets of parameters (Strain, Copper catalysis, Ruthenium catalysis…). Functional lipids are designed to react after cubosome formation but could also enter the preparation of cubosomes in a one-pot process. Multicompartment nanocarrier cubosomes were recently demonstrated through incorporation of amphiphilic cyclodextrins (CD) that could carry water insoluble substances [Zerkoune, 2016]. In this project, the channels surfaces will be functionalised with CDs by in-situ reactions. Cyclodextrins will be considered as:



i) model molecules to link to the internal cubosome membrane in the aqueous channel (e.g. common Azido-cyclodextrin)

ii) carrier of hidden molecules to the membrane

iii)cages to control release and modulate affinity constants, typically of moderately hydrophilic compound with known affinity toward cyclodextrin cavity.



Importantly, according to their ring size, Cds and interaction capability, CDs can offer multiple specific behaviour with pluronic stabilizers. With little chemical effort, inclusion compounds could be favoured or hampered. Structure determination. In addition to X-ray and other standard techniques, deuterated species will be synthesized for structure determination by contrast matching in neutron scattering. Deuterated MO will be prepared in a multistep yet simple synthesis from deuterated oleic acid [Darwish, 2013]. Mixtures of deuterated unmodified MO and chemically modified MO will allow controlling the degree of mixing of the modified molecules with bare ones. Deuterated compounds will also allow NMR experiments to inspect diffusion phenomena, reaction kinetics, and membrane organization.





[Angelova, 2015] Angelov, B., Angelova, A., Drechsler, M., Garamus, V.M., Mutafchieva, R. and Lesieur, S. (2015) Identification of large channels in cationic PEGylated cu- bosome nanoparticles by synchrotron radiation SAXS and Cryo-TEM imaging. Soft Matter, 11, 3686–3692, 2015.

[Astolfi, 2017] Astolfi, P.; Giorgini, E.; Gambin, V.; … Vita, F.; Francescangeli, O.; Marchini, C. & Pisani, M. (2017), Lyotropic Liquid- Crystalline Nanosystems as Drug Delivery Agents for 5-Fluorouracil: Structure and Cytotoxicity, Langmuir 33, 12369-12378.

[Barriga, 2018] Barriga H.M.G., Holme M.N. and Stevens M.M. (2018), Cubosomes: the next generation of smart lipid nanoparticles, Angew. Chemie Int. Ed. 57, 2.

[Chong, 2011] Chong, Y.T.J., Mulet, X., Waddington, L.J., Boyd, B.J. and Drummond, C.J. (2011), Steric stabilisation of selfassembled cubic lyotropic liquid crystalline nanoparticles: high throughput evaluation of triblock polyethylene oxide-polypropylene

oxide-polyethylene oxide copolymers. Soft Matter, 7:4768.

[Darwish, 2013] Darwish, T.A., Luks, E., Moraes, G., Yepuri, N.R., Holden, P.J., James, M., (2013), Synthesis of deuterated oleic acid and its phospholipid derivative [D64]dioleoyl-sn-glycero-3-phosphocholine. J. Label. Compd. Radiopharm. 56, 520–529.

[Elamari, 2010] Elamari, H., Jlalia, I., Louet, C., Herscovici, J., Meganem, F., Girard, C., (2010), On the reactivity of activated alkynes

in copper and solvent-free Huisgen’s reaction. Tetrahedron Asymmetry, Henri Kagan: An 80th Birthday Celebration Special Issue – Part 1 21, 1179–1183.

[Falchi, 2015] Falchi, A.M., Rosa, A., Atzeri, A., Incani, A., Lampis, S., Meli, V., Caltagirone, C. and Murgia, S., (2015), Effects of

monoolein-based cubosome formulations on lipid droplets and mitochondria of HeLa cells. Toxicology Research, 4, 1025-1036.

[Garg, 2006] Garg, G.; Singh, D.; Saraf, S. & Saraf, S. (2006), Management of benign prostate hyperplasia: An overview of alphaadrenergic

antagonist, Biological & Pharmaceutical Bulletin. 29, 1554-1558.

[Hyde, 1984] Hyde, S.T. and Andersson S.A (1984) Cubic structure consisting of a lipid bilayer forming an infinite periodic minimum

surface of the gyroid type in the glycerol monooleate-water system. Crystalline Materials, 1984.

[Kluzek, 2017] Kluzek, M., Tyler, A.I., Wang, S., Chen, R., Marques, C.M., Thalmann, F., Seddon, J.M. and Schmutz, M., 2017. Influence of a pH-sensitive polymer on the structure of monoolein cubosomes. Soft Matter, 13, 7571-7577.

[La, 2014] La, Y.; Park, C.; Shin, T. J.; Joo, S. H.; Kang, S. & Kim, K. T. (2014), Colloidal inverse bicontinuous cubic membranes of block copolymers with tunable surface functional groups, Nat. Chem. 6(6), 534-541.

[Landh, 1994] Landh, T. (1994), Phase behavior in the system pine needle oil Monoglycerides-Poloxamer 407-Water at 20ºC. J. Phys. Chem., 98, 8453.

[Li, 2015] Li, J.C., Zhu, N., Zhu, J.X., Zhang, W.J, Zhang, H.M., Wang, Q.Q, Wu, X.X., Wang, X., Zhang, J. and Hao, J.F. (2015) Self- Assembled cubic liquid crystalline nanoparticles for transdermal delivery of paeonol. Med Sci Monit., 21, 3298–3310.

[Luzzati, 1962] Luzzati V . and Husson F. (1962) The structure of the liquid-crystalline phases of lipid-water systems., J Cell Biol, 12(2):207–219.

[Osornio, 2012] Osornio, Y. M.; Uebelhart, P.; Bosshard, S.; Konrad, F.; Siegel, J. S. & Landau, E. M. (2012), Design and Synthesis

of Lipids for the Fabrication of Functional Lipidic Cubic-Phase Biomaterials, JOC 77, 10583-10595.

[Scriven, 1976] Scriven, L.E.(1976) Equilibrium bicontinuous structure. Nature, 263(5573):123–125

[Zerkoune, 2016] Zerkoune, L., Lesieur, S., Putaux, J.-L., Choisnard, L., Gèze, A., Wouessidjewe, D., Angelov, B., Vebert-Nardin, C., Doutch, J., Angelova, A. (2016), Mesoporous self-assembled nanoparticles of biotransesterified cyclodextrins and nonlamellar lipids as carriers of water-insoluble substances. Soft Matter 12, 7539–7550.

“Smart” Composite Membranes for Lithium-Metal-Polymer Batteries.

SL-DRF-19-0850

Research field : Soft matter and complex fluids
Location :

Laboratoire Léon Brillouin

Groupe Biologie et Systèmes Désordonnés

Saclay

Contact :

Quentin BERROD

Jean-Marc ZANOTTI

Starting date : 01-10-2019

Contact :

Quentin BERROD

CNRS - DRF/INAC/SyMMES/STEP

(+33)(0)438786425

Thesis supervisor :

Jean-Marc ZANOTTI

CEA - DRF/IRAMIS/LLB/GBSD

+33(0)476207582

Personal web page : http://iramis.cea.fr/Pisp/jean-marc.zanotti/

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

More : https://icr-amu.cnrs.fr/

At the present stage, in the electrochemical device landscape, solid-state polymer lithium batteries offer an interesting compromise in terms of specific stored energy and power. Nevertheless, to achieve practical conduction they need to operate at relatively high temperature (80°C). This condition significantly hampers the performances of the system. The top-one priority of manufacturers in the field is to decrease the working temperature of their products. This project proposes a fundamental science approach targeting the delivery of a “proof of concept” polymer based lithium metal battery working at room temperature.



This ambitious goal will be achieved by taking advantage of i) the confinement of the electrolyte within composite Carbon NanoTube (CNT) membranes (Gibbs-Thomson effect), ii) one-dimensional (1D) ionic conductivity, and iii) the use of low molecular mass PEO (high mobility). The reduction of dimensionality will be obtained by using the quasi-perfect 1D topology offered by vertically aligned CNT forests.



The suppression of the electrical conductivity of the CNT is a critical aspect to use 1D CNT membranes as battery separators. Short PEO chains will be therefore grafted onto the CNT caps to achieve at once good ionic conduction at the CNT pore entrance and ensure electrical insulation of the CNT/electrode contact. Depending on the physico-chemical conditions on one side of the membrane (pH, temperature…), one can expect drastic changes in the conformation of the CNT-tips-grafted-polymer layer: from extended to mushroom conformation. Therefore, beyond the present project, such smart membranes could be turned into “nano-valves”, able to gate the flow between different media.

Biophysical and dynamical study of chromatin conformation during genome replication

SL-DRF-19-0435

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 and other cellular events 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 use different cell mutants and the addition of drugs to perturb the system and modify the observed structures.



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.

Self-assembled metamaterials made by block copolymers

SL-DRF-19-0901

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

Starting date : 01-10-2018

Contact :

Patrick GUENOUN

CEA - DRF/IRAMIS/NIMBE/LIONS

01-69-08-74-33

Thesis supervisor :

Patrick GUENOUN

CEA - DRF/IRAMIS/NIMBE/LIONS

01-69-08-74-33

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.

Lithium metal polymer" Batteries: towards operation at ambient temperature

SL-DRF-19-0563

Research field : Soft matter and complex fluids
Location :

Laboratoire Léon Brillouin

Groupe Biologie et Systèmes Désordonnés

Saclay

Contact :

Jean-Marc ZANOTTI

Starting date : 01-10-2019

Contact :

Jean-Marc ZANOTTI

CEA - DRF/IRAMIS/LLB/GBSD

+33(0)476207582

Thesis supervisor :

Jean-Marc ZANOTTI

CEA - DRF/IRAMIS/LLB/GBSD

+33(0)476207582

Personal web page : http://iramis.cea.fr/Pisp/jean-marc.zanotti/

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

More : http://liten.cea.fr/cea-tech/liten/Pages/Accueil.aspx

This PhD subject proposes an original way to allow the use of "lithium metal polymer" batteries at room temperature. This objective will be achieved by combining three effects:

i) The nanometric confinement of the electrolyte in membranes based on vertically aligned Carbon NanoTubes (VA-CNT),

ii) The use of low molecular weight polymer (here Poly(Ethylene Oxide (PEO))

iii) One-dimensional ionic conduction.



The conduction of the CNT confined Lithium will be driven by two characteristic distances: the pore diameter (1-4 nm) and the total VA-CNT length (from 10 to 500 micrometers). Rational modeling of the transport properties over distances differing by orders of magnitude naturally calls for a multiscale approach.

Therefore, as for its fundamental Science aspect, the primary goal is to develop an experimental multi-scale approach to bridge the broad time and spatial scales (eight orders of magnitude) relevant to the high-mobility-in-tight-1D-spaces we are seeking.

The applied research fold of the study is to prove the validity of the concept.

Single-ion hybrid polymer electrolytes for Li-metal battery

SL-DRF-19-0554

Research field : Soft matter and complex fluids
Location :

Laboratoire Léon Brillouin

Groupe de Diffusion Neutron Petits Angles

Saclay

Contact :

Jacques JESTIN

Starting date : 01-10-2019

Contact :

Jacques JESTIN

CNRS - LLB01/Laboratoire de Diffusion Neutronique

0661476825

Thesis supervisor :

Jacques JESTIN

CNRS - LLB01/Laboratoire de Diffusion Neutronique

0661476825

Fabrication of omniphobic surfaces

SL-DRF-19-0656

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 :

Christophe FAJOLLES

Patrick GUENOUN

Starting date : 01-11-2019

Contact :

Christophe FAJOLLES

CEA - DSM/IRAMIS/NIMBE/LIONS

01 69 08 99 60

Thesis supervisor :

Patrick GUENOUN

CEA - DRF/IRAMIS/NIMBE/LIONS

01-69-08-74-33

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

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

For many applications (defrosting, anti-adhesion, cleaning) one aims at surfaces where consensed droplets can be easily removed. The usual method for water is to create hydrophobic surface coatings to create water droplets with a high contact angle and a low hysteresis force: the drops are then easily evacuated under the influence of gravity for example. However, these coatings are generally not very effective for oil drops and are often fragile in the long term. In addition, the coatings may consist of chemical species that will be soon regulated or banned or, in the case of nanostructured coatings, are too sensitive to the pressure that makes them ineffective (impalment transition).



In this PhD project, in collaboration with an industrial partner, we propose to explore a new strategy recently developed in our laboratory and in the literature and which consists in creating a liquid-like coating : as nanostructured surfaces mimick lotus leaves, this strategy is inspired from pitcher plants [1]. A first method consists to infusing a liquid in a porous layer [2] but the stability of the liquid can be problematic. More recently, polymers of poly (dimethylsiloxane) kind, grafted or adsorbed on glass surfaces have shown such liquid-like behaviors such as condensed oil drops could slide very easily [3,4]. Yet convincing similar properties for drops of water have not been shown yet since the remnant hysteresis is still quite large.



We therefore propose a training and doctoral project that will consist of optimizing truly omniphobic surfaces. To do this, we will explore different types of polymers and different methods of adsorpton or grafting by controlling especially the chemical nature of surface groups and the associated surface energy as well as the behavior of drops on the surfaces. Particular attention will be paid to the thermal annealing of the layers as well as to their aging over time upon pH variations notably.





[1] Bohn H.F., Federle W., 14138–14143 PNAS September 28, 2004 vol. 101 no. 39

[2] Wong, T. S.; Kang, S. H.; Tang, S. K.; Smythe, E. J.; Hatton, B.

D.; Grinthal, A.; Aizenberg, J. Bioinspired Self-Repairing Slippery

Surfaces with Pressure-Stable Omniphobicity. Nature 2011, 477, 443-

447.

[3] Wang, L.; McCarthy, T. J. Covalently Attached Liquids: Instant

Omniphobic Surfaces with Unprecedented Repellency. Angew. C hem.,

Int. Ed. 2016, 55, 244-248.

[4] Liu, P.; Zhang, H.; He, W .; Li, H.; Jiang, J.; Liu, M.; Sun, H.; He,

M.; Cui, J.; Jiang, L.; Yao, X. Development of “Liquid-Like”

Copolymer Nanocoatings for Reactive Oil-Repellent Surfac e. ACS

Nano 2017, 11 (2), 2248-2256.

Atomic Transport in Nanocrystalline Metals

SL-DRF-19-0705

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

Laboratoire des Solides Irradiés

Laboratoire des Solides Irradiés

Saclay

Contact :

Vassilis PONTIKIS

Gianguido Baldinozzi

Starting date : 01-10-2019

Contact :

Vassilis PONTIKIS

CEA - DRF/IRAMIS

0169082904

Thesis supervisor :

Gianguido Baldinozzi

CNRS-Ecole Centrale-Supelec Paris - SPSMS

Personal web page : https://www.researchgate.net/profile/Vassilis_Pontikis

This project aims at unravelling the atomic scale mechanisms of mass transport and recrystallization in nano-crystalline metallic samples via atomic scale simulations relying on near-transferable n-body potentials adapted to noble metals. It is legitimate to ask whether the grain growth in nano-crystalline metallic materials relies upon the same mechanisms observed in microcrystalline materials or the grain growth in nano-crystalline materials involves a different “new” physics. The available experiments do not support the idea that crystal growth in metallic nano-crystals can be simply extrapolated from the processes observed in micrometric crystals, but no definitive answer is available about the underlying physical mechanisms. Computational experiments focusing on atomic transport in nano-crystalline systems will be compared with experiments and theoretical models, which have evidenced the unexpected existence in metallic nano-crystals of a linear grain growth below a critical grain size.

Multifunctional material for the energy transition and opto-spintronics, based on N-doped BaTiO3

SL-DRF-19-0483

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 : 01-10-2019

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/antoine.barbier/

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

N-doped oxides and/or oxinitrides constitute a booming class of compounds with a broad spectrum of useable properties and in particular for novel technologies of carbon-free energy production and optoelectronics. The insertion of nitrogen in the crystal lattice of an oxide semiconductor allows modulating the value of the optical band gap, enabling new functionalities. The production of corresponding single crystalline thin films is highly challenging. In this thesis work, single crystalline N-doped oxides heterostructures will be grown by atomic plasma-assisted molecular beam epitaxy. BaTiO3 will provide ferroelectricity and a favorable absorption spectrum while an additional ferrimagnetic ferrite will give an artificial (opto)multiferroic character. The resulting structures will be investigated with respect to their ferroelectric characteristics, their magneto-electric and optoelectronic couplings and their performances in solar water splitting photo-electrolysis, as a function of the N doping. These observations will be correlated with a detailed understanding of crystalline and electronic structures.



The student will acquire skills in ultra-high vacuum techniques, molecular beam epitaxy, magnetometry and photo-electrolysis as well as in state of the art synchrotron radiation techniques.

Fracture properties of bone-inspired mechanical metamaterials: toward lightweight and resistant solids

SL-DRF-19-0465

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.

Theoretical study of graphene electrodes for Molecular Electronics

SL-DRF-19-0779

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 : 01-10-2019

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.

Theoretical study of coupled electronic and heat transports to design thermoelectric materials at ambient temperature

SL-DRF-19-0533

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

Laboratoire des Solides Irradiés

Laboratoire des Solides Irradiés

Saclay

Contact :

Nathalie VAST

Starting date : 01-10-2019

Contact :

Nathalie VAST

CEA - DRF/IRAMIS/LSI/LSI

01 69 33 45 51

Thesis supervisor :

Nathalie VAST

CEA - DRF/IRAMIS/LSI/LSI

01 69 33 45 51

Personal web page : https://www.polytechnique.edu/annuaire/fr/users/nathalie.vast

Laboratory link : https://portail.polytechnique.edu/lsi/fr/recherche/theorie-de-la-science-des-materiaux

Thermoelectricity have proven to offer a viable solution for the generation of electrical power (Seebeck effect) and to the problem of overheating in nanodevices (Peltier effect). New technological and scientific efforts are needed to find low-cost efficient materials that will develop the use of thermoelectric devices working at ambient temperature. Numerical simulations, which are the heart of this Ph.D. subject, provide a highly valuable tool to reach this end.



The theoretical method that will allow the prediction of the effect of nanostructuring on the figure of merit ZT will be developed and an integrated simulation tool to evaluate both the diffusive and the phonon-drag contributions to the Seebeck coefficient i.e., the contribution due to electron-phonon coupling, will be provided. This fully ab initio approach will be applied to germanium (abundant and non-toxic) and bismuth (among the material with the highest Seebeck coefficient), achieving a parameter-free description of thermoelectricity for these materials, their nanostructures and their compounds (Si-Ge alloys and Bi2Te3).



The BTEs (Boltzmann transport équations) for the electronic and the phonon system, coupled through electron-phonon interaction, will be solved beyond standard approximations. The phonon-phonon anharmonicity and the phonon scattering with surfaces and interfaces in nanostructures will be taken into account, with the aim of tayloring the phonon system to increase the thermoelectric effect.The electron-phonon coupling will be computed with a recent method based on the interpolation in the Wannier space. Finally, the DFT-based results for the electron-phonon coupling will be coupled to a Monte Carlo transport code, opening the

possibility to model even complex nano-devices based on the materials that will be theoretically studied.

Ab initio simulations of spin polarized STM images

SL-DRF-19-0780

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 : 01-10-2019

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.

Molecular dynamics simulations of amorphous phase separated glasses

SL-DRF-19-0033

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 : 01-10-2019

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.

Electromechanical control of surface topological domain walls

SL-DRF-19-0384

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 : 01-10-2019

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/87/nick.barrett.html

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

In ferroelectric or ferroelastic materials, domains form to minimize the electrostatic and mechanical contributions to the free energy, separated by Domain Walls (DW). DWs break translational symmetry to exhibit astonishing and very different properties compared to their parent materials, including conductivity, superconductivity and polarity. As a result, they could become a completely novel paradigm for nanoelectronics, in which the wall is the active element of the device. A reproducibly switchable 2D polar or conducting object in a dielectric medium would provide a route to extremely high storage densities with very low switching power per bit. The thesis will address walls between ferroelastic and ferroelectric domains.

Bulk single crystal ferroelectrics (BaTiO3), ferroelastics (CaTiO3) and epitaxial thin films (ferroelectrics BaTiO3, PbTiO3 and ferroelastic CaTiO3) will be studied. Low Energy and Photoemission Electron Microscopy will map the electrical topography, local chemistry and electronic structure of the domain walls. Dedicated set-ups for in-situ imaging of domain walls as a function of applied stress and electric field will be used for in operando experiments. In collaboration with Prof. Ekhard Salje (University of Cambridge) a mechanical model based will be used to simulate the emergence of polarity from strain gradients.

Ab initio simulation of transport phenomena in atomic-scale junctions

SL-DRF-19-0723

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 : 01-09-2019

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)

Hybrid carbon nanotube optoelectronic devices for silicon photonics

SL-DRF-19-0721

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 : 01-10-2019

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).

In operando study of ferrite - perovskite multiferroic encapsulated microstructures

SL-DRF-19-0808

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 : 01-10-2019

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 multiferroic 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 proposed thesis work consists of a close collaboration between CEA/SPEC and SOLEIL synchrotron (HERMES beamline). 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 behaviour of these inclusions under functioning conditions will be examined using the most advanced synchrotron radiations techniques and in particular spectromicroscopy, 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, magnetometry as well as in the above mentioned state of the art synchrotron radiation techniques.

Detection of micronic and submicronic objects with a labo on chip based on GMR sensors

SL-DRF-19-0361

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

Stéphanie SIMON

Starting date : 01-02-2018

Contact :

Guenaelle Jasmin-Lebras

CEA - DRF/IRAMIS/SPEC/LNO

01 69 08 65 35

Thesis supervisor :

Stéphanie SIMON

CEA - DRF/Joliot/DMTS/SPI/LERI

01 69 08 77 04

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

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

The development of early diagnosis techniques is a real challenge in the medical or defence domain. The aim is to obtain a lab on chip able to quickly detect, in a simple, sensitive and specific way, various rare biological objects in response to an urgent need for clinical diagnosis and/or biosecurity. For this purpose, the approach proposed by LERI and LNO is very innovative. It is based on the combination of specific labelling of antibodies developed at the LERI with magnetic nanoparticles and their dynamic detection with magnetic sensors based on highly sensitive spin electronics. This topic is currently the subject of a thesis, which has carried out the proof of concept study for the specificity of the test using a model of a murine myeloma cells. A new, more efficient device, with sensors on both sides of the microfluidic channel, has been developed. During this new thesis carried out in collaboration with the LERI, the aim will be to demonstrate that this lab on a chip is able to achieve sufficient performance to detect smaller biological objects like bacteria.

The LERI has already developed antibodies against various bacteria (Bacillus thuringiensis gram(+) bacterial spores, Salmonella Typhimurium gram(-) bacteria) used as models for the study of biological threat bacteria. At the LERI, the student will functionalize magnetic particles with various antibodies against these bacteria.

At the LNO, the student will aim to develop laboratories on a chip and evaluate their performance and robustness. He/she will have to learn how to manufacture them using the different techniques available in the department (clean room, laser cutting, deposit machines). He/she will have to design a transportable shielded device against magnetic noise in order to perform measurements at the LERI in a high microbiological safety level 2 environment. It will adapt the simulation and acquisition programs to the simultaneous detection of a bacterium by two sensors.

Theoretical study of the physical and optical properties of some titanium oxide surfaces for gas sensing applications

SL-DRF-19-0532

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

Laboratoire des Solides Irradiés

Laboratoire des Solides Irradiés

Saclay

Contact :

Nathalie VAST

Starting date : 01-10-2019

Contact :

Nathalie VAST

CEA - DRF/IRAMIS/LSI/LSI

01 69 33 45 51

Thesis supervisor :

Nathalie VAST

CEA - DRF/IRAMIS/LSI/LSI

01 69 33 45 51

Personal web page : https://www.polytechnique.edu/annuaire/fr/users/nathalie.vast

Laboratory link : https://portail.polytechnique.edu/lsi/fr/recherche/theorie-de-la-science-des-materiaux

The international community under the auspices of the United Nation Framework Convention on Climate Change (UNFCCC) is engaged in developing the policy to reduce greenhouse gases (GHGs) emission and minimize the risks of climate change. Consequently, it is very important to develop a low power, high performance sensor suitable to monitor the GHGs for proper mitigation. A common and existing method for sensing the concentration of gases is by using semiconducting metal oxides like SnO2, ZnO, and TiO2. Some models emphasize the importance of charge transfer in the sensing mechanism, but an study from first principles, including the electronic coupling with phonons, is necessary to understand quantitatively the adsorption process and the consequent optical response of the system.



The optical response and electron-phonon coupling will be in investigated with methods based on the time-dependent density functional theory on which the host team has developed an expertise. Numerical simulations will be performed with the Quantum ESPRESSO package. Part of the project may consist of theoretical and numerical implementations. The Ph.D. subject requires the candidate to be highly motivated by modelling, computing and programming.

Linear magnetoelectric and multiferroic properties in A4A’2O9 antiferromagnets

SL-DRF-19-0539

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

Laboratoire Léon Brillouin

Groupe Diffraction Poudres

Saclay

Contact :

Françoise Damay

Starting date : 01-10-2019

Contact :

Françoise Damay

CEA - DRF/IRAMIS/LLB/GDP

0169084954

Thesis supervisor :

Françoise Damay

CEA - DRF/IRAMIS/LLB/GDP

0169084954

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

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

The general context of this PhD work is the search for new multiferroics, compounds in which magnetisation and electric polarization are coupled, allowing for instance a magnetic field to modify the polarization, of an electric field to change magnetization.



In the proposed work, a new family of promising multiferroics will be investigated, namely niobiates and tantalates of general formula A4A'O9 with A a divalent transition metal. In work published in 2018, it was shown that in particular Fe4Ta2O9 exhibits both multiferroic and linear magneto-electric properties, depending on the temperature range. This suggests different spin/charge couplings that remain to be explored and understood. Experimental techniques will be devoted to the understanding of the relations ships between crystal and magnetic structures and physical properties: for the most part, the student will deal with magnetization, dielectric constant and polarization measurements, coupled with X-ray and neutron diffraction experiments versus temperature.

Water photo-electrolysis assisted by an internal potential

SL-DRF-19-0755

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.

Electronic properties of two-dimensional semiconductors

SL-DRF-19-0735

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 :

Vincent DERYCKE

Starting date : 01-10-2019

Contact :

Vincent DERYCKE

CEA - DRF/IRAMIS/NIMBE/LICSEN

0169085565

Thesis supervisor :

Vincent DERYCKE

CEA - DRF/IRAMIS/NIMBE/LICSEN

0169085565

Personal web page : http://iramis.cea.fr/Pisp/vincent.derycke/

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

Two-dimensional materials (graphene, phosphorene, BN monolayers…), which have atomic thickness, have been attracting enormous attention from the scientific community since 2004. Among them, 2D semiconductors such as monolayers of transition metal dichalcogenides (MoS2, MoSe2, WS2…) have a high potential for future applications in electronics, optics, and as materials for renewable energies (MoS2 is for example an excellent catalyst for hydrogen production). These materials exist at the natural state (within 3D natural crystals that can be exfoliated down to individual monolayers) and/or can be synthetized in the laboratory, in particular using chemical vapor deposition (CVD). In both cases, 2D materials present inhomogeneities (edges, defects, folds, vacancies, double-layers...). Yet at that scale, such features can drastically impact their properties (the charge mobility, the luminescence yield, the catalytic efficiency...). It is thus important to study these properties with local techniques that allow understanding the role of inhomogeneities and to either reduce or maximize their impact. In this context, the LICSEN team of the NIMBE Unit synthetizes monolayer MoS2 (by CVD) and study its electronic properties within devices such as field-effect transistors as well as its electro-catalytic properties by electrochemistry. In this PhD project, conducted in strong collaboration with other academic partners, we aim at developing new measurement techniques for the study of ultrathin semiconductors at the local scale using notably high-contrast microscopy on antireflection substrates [1,2] and local probe techniques coupled to electrical measurements (EFM, KPFM).



[1] Campidelli et al., Backside absorbing layer microscopy: Watching graphene chemistry, Science Advances 3, e1601724 (2017).

[2] Jaouen et al., Ideal optical contrast for 2D materials observation using antireflection absorbing substrates, submitted

Hematite based photoelectrodes for low power consumption solar water splitting

SL-DRF-19-0476

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

Service de Physique de l'Etat Condensé

Laboratoire Nano-Magnétisme et Oxydes

Saclay

Contact :

Dana STANESCU

Gheorghe Sorin Chiuzbaian

Starting date : 01-10-2019

Contact :

Dana STANESCU

CEA - DRF/IRAMIS/SPEC/LNO

01 69 08 75 48

Thesis supervisor :

Gheorghe Sorin Chiuzbaian

Université Sorbonne, Université Pierre et Marie Curie - Laboratoire de Chimie Physique Matière et Rayonnement

+33 1 44 27 66 15

Personal web page : http://iramis.cea.fr/Pisp/dana.stanescu/

Laboratory link : https://speclno.org/oxide%20nanorod.php

More : https://www.synchrotron-soleil.fr/fr/lignes-de-lumiere/HERMES

Hydrogen production by water splitting is a clean and viable approach to the world’s energy needs, yet it is very greedy in electrical energy consumption necessary to overcome the water redox potential. In order to reduce the energy consumption, we study the possibility of employing solar radiation, which, absorbed by identified and optimized semiconductor oxides, generates electron-hole pairs that will participate to redox reactions in a photo-electrolysis cell. Using a photo-anode and a photo-cathode in tandem configuration, hydrogen production could naturally occur via solar water splitting, without any electrical energy input to initiate the reaction.



The PhD student will first optimize the growth of hematite-based photo-electrodes by aqueous chemical growth. This method allows obtaining nanostructured films in the form of nano-rods, which are oriented perpendicularly to the substrate. Photo-anodes and photocathodes will be obtained by doping hematite with Ti and Mg or Zn, respectively. Photo-electrochemical activity will be correlated with surface morphology using techniques such as SEM and AFM, or with the surface potential measurements using the KPFM. In addition, a micro-spectroscopic approach using the STXM at the HERMES beamline at SOLEIL synchrotron, will allow probing the chemical composition and the electronic structure of the photo-electrodes at nanometric scales. These techniques will reveal the microscopic origin of the photoconduction properties. Moreover, they will provide the keys of optimizing the photo-electrodes via the physico-chemical parameters.

Ultra-fast Spintronics with antiferromagnetic insulators

SL-DRF-19-0913

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 : 01-10-2019

Contact :

Michel VIRET

CEA - DRF/IRAMIS/SPEC/LNO

01 69 08 71 60

Thesis supervisor :

Michel VIRET

CEA - DRF/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/

Among the ordered electronic states that occur in solid-state materials, magnetism is uniquely robust, persisting to well above room temperature in a wide variety of materials. Ferromagnets are now routinely used in the field of information technology. On the other hand, antiferromagnets (AF), which compose the overwhelming majority of magnetically ordered materials, have not been considered as candidates for active elements. In these materials, the magnetic moments of atoms align in a regular pattern with neighbouring spins pointing in opposite directions. Because of their zero net moment, antiferromagnets are rather insensitive to a magnetic field and difficult to probe. Thus, their intrinsic properties, and especially AF domains formation and the mobility of their domain walls, are poorly known.



In the last few years, it has been demonstrated that metallic antiferromagnets can lead to giant-magnetoresistance effects (resulting from spin-orbit-coupling), which validates their use as “spintronic elements”. On the other hand, insulating antiferromagnets are much more common than their conducting counterparts because super-exchange interactions in insulators are mainly antiferromagnetic. Direct control of AF properties requires unpractically large magnetic fields, not commonly available in a laboratory. The recent development of the spin transfer torque effect produced by spin polarized currents provides an ideal way of generating (the equivalent of) a staggered field, ideal to control the AF order. This should allow to toggle AF domains and influence the AF dynamical properties, but this has not yet been demonstrated.



The PhD work proposed here aims at assessing the potential of AF insulators in spintronics. These materials will be manipulated using pure spin currents generated through a newly discovered effect based on the ultra-fast demagnetization of an adjacent ferromagnetic layer. Both excitation and measurement will be carried out using a femtosecond laser.

Numerical simulations will also be developed through on an existing home-made code based on the dynamical resolution of the Landau-Lifshitz-Gibert equation on localised spins.

Magnetization dynamics of nanostructures in strongly out-of-equilibrium regimes

SL-DRF-19-0955

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 : 01-10-2019

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 : https://www.speclno.org

This thesis aims at investigating, understanding and controlling the linear and nonlinear regimes of magnetization dynamics in individual nanostructures made of magnetic materials with very weak damping. An original near field microscopy technique developed in the host laboratory to detect the spin dynamics at the nanoscale will be employed to perform experiments, and analytical tools as well as micromagnetic simulations will be used for their interpretation. This work will take place in the framework of an ANR project whose goal is to demonstrate the manipulation of high amplitude coherent spin waves in devices combining concepts of magnonics and spintronics.



Keywords: magnetization dynamics; nanomagnetism; spintronics; magnonics; nonlinear dynamical systems

Methods: magnetic force microscopy; high frequency techniques; micromagnetic simulations

Modelling of the pulsating heat pipe

SL-DRF-19-0488

Research field : Thermal energy, combustion, flows
Location :

Service de Physique de l'Etat Condensé

Systèmes Physiques Hors-équilibre, hYdrodynamique, éNergie et compleXes

Saclay

Contact :

Vadim Nikolayev

Starting date : 01-10-2019

Contact :

Vadim Nikolayev

CEA - DRF/IRAMIS/SPEC/SPHYNX

+33169089488

Thesis supervisor :

Vadim Nikolayev

CEA - DRF/IRAMIS/SPEC/SPHYNX

+33169089488

Personal web page : http://iramis.cea.fr/Pisp/vadim.nikolayev/

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

More : http://iramis.cea.fr/Phocea/Vie_des_labos/Ast/ast_visu.php?id_ast=2271&id_unit=9&id_groupe=214

The thermal management of the components of vehicles or electronic devices is necessary to prevent overheating of the heat-emitters (like engines, processors, etc.) and to recover the heat to use elsewhere. Increasingly effective means of transfer of heat are required. The Pulsating Heat Pipe (PHP) is a promising solution well suitable for the transfer of high powers. The PHP is an extremely simple system. It is a closed capillary tube filled with a two-phase liquid able to transfer heat from its hot part (evaporator) to the cold part (condenser). Neither wick nor internal complex structure are required. The internal diameter of the tube needs to be small so that the alternating liquid plugs and vapor bubbles form inside it. The tube meanders between the evaporator and condenser thus forming multiple branches (i.e. parallel tubes). It turns out that the self-sustained oscillating motion of bubbles and plugs begin in this system when the temperature difference between the condenser and evaporator is applied. Such a convective motion and caused by it convective heat transfer make PHP extremely efficient with respect to other types of heat pipes. However, contrary to them, its functioning is non-stationary and thus more difficult to understand and model. The aim of the thesis is two-fold. First, we need to theoretically understand the hydrodynamic flow of a Taylor bubble in the presence of oscillations and phase change. Second, the collective behavior of all the bubbles inside PHP will be studied with the methods of non-linear dynamics and the computer code CASCO (French abbreviation meaning Advanced Code of PHP Simulation) developed at CEA. This is essential for mastering different oscillation regimes in order to convert CASCO into a design tool for industrial applications. The work will be conducted in collaboration with experimental groups within national and international research projects.

SL-DRF-19-0420

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 :

Yves BOULARD

Serge PIN

Starting date : 01-09-2019

Contact :

Yves BOULARD

CEA - DSV/IBITEC-S/SB²SM

+33 169083584

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=spin

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

More : http://joliot.cea.fr/drf/joliot/Pages/Entites_de_recherche/I2BC_saclay/sb2sm.aspx

Exploring the formation of gold nanostars

SL-DRF-19-0869

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 :

Fabienne TESTARD

Damien Alloyeau

Starting date : 01-10-2019

Contact :

Fabienne TESTARD

CEA - DRF/IRAMIS/NIMBE/LIONS

01 69 08 96 42

Thesis supervisor :

Damien Alloyeau

CNRS - laboratoire MPQ

01 57 27 69 83

Personal web page : http://iramis.cea.fr/Pisp/94/fabienne.testard.html

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

More : http://www.mpq.univ-paris-diderot.fr/?-microscopie-electronique-avancee-

Controlling the optical properties of Au nanoparticles requires mastering their shape during the fabrication processes. If a wide variety of nanoparticle shapes has been reported, recent attention has shifted towards the synthesis of Au nanostars (NSs) which provide an opportunity to expand the broadening horizon of applications of gold nano-objects. The distinguishing feature of Au NSs over other morphologies is the presence of arms with sharp tips that give rise to narrow and tuneable localized surface plasmon resonances (LSPRs) throughout the entire visible and near IR spectrum holding great promise for bio-imaging and therapeutic applications and surface enhanced Raman spectroscopy (SERS). Nevertheless, current synthetic methods have a limited control over the symmetry of gold NSs (i.e. variations in the distribution, number, length and shape of arms). This morphological arbitrariness makes the understanding of their optical properties inherently difficult and has detrimental effect on the reproducibility of their applications. This phD project aims at gaining control over the shape and stability of Au NSs, by exploiting unprecedented in situ liquid TEM and in situ SAXS insights on the growth and degradation processes of these complex nanostructures. The phD will be shared between two Laboratories: "le laboratoire des Matériaux et Phénomènes quantiques", CNRS at the Université Paris Diderot and "Le Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire" in NIMBE CNRS/CEA at CEA Saclay.

 

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