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PhD subjects

Dernière mise à jour : 13-12-2017

34 sujets IRAMIS

• Analytic chemistry

• Chemistry

• Mesoscopic physics

• Molecular biophysics

• Physical chemistry and electrochemistry

• Radiation-matter interactions

• Soft matter and complex fluids

• Solid state physics, surfaces and interfaces

• Ultra-divided matter, Physical sciences for materials

 

Ab initio study of electronic properties of Calcium Oxalate

SL-DRF-18-0461

Location :

Laboratoire des Solides Irradiés (LSI)

Laboratoire des Solides Irradiés (LSI)

Saclay

Contact :

Francesco SOTTILE

Starting date : 01-10-2018

Contact :

Francesco SOTTILE

Ecole Polytechnique - UMR 7642

0169334549

Thesis supervisor :

Francesco SOTTILE

Ecole Polytechnique - UMR 7642

0169334549

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

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

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

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



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

Metal Organic frameworks for new generation of Li-air batteries

SL-DRF-18-0302

Location :

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

Laboratoire d'étude des éléments légers (LEEL)

Saclay

Contact :

Suzy SURBLE

Hicham KHODJA

Starting date : 01-10-2018

Contact :

Suzy SURBLE

CEA - DRF/IRAMIS/NIMBE/LEEL

+ 33 1 69 08 81 90

Thesis supervisor :

Hicham KHODJA

CEA - DRF/IRAMIS/NIMBE/LEEL

01 69 08 28 95

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

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

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

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

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

Digital Microfluidic hyphanated ICPMS : Droplet Generator introduction system study

SL-DRF-18-0452

Research field : Analytic chemistry
Location :

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

Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire (LIONS)

Saclay

Contact :

Valérie GEERTSEN

Starting date : 01-10-2018

Contact :

Valérie GEERTSEN

CEA - DRF/IRAMIS/NIMBE/LIONS

0169084798

Thesis supervisor :

Valérie GEERTSEN

CEA - DRF/IRAMIS/NIMBE/LIONS

0169084798

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

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

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

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



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



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

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

SL-DRF-18-0330

Research field : Analytic chemistry
Location :

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

Laboratoire Structure et Dynamique par Résonance Magnétique (LCF) (LSDRM)

Saclay

Contact :

Lionel DUBOIS

Patrick BERTHAULT

Starting date : 01-10-2018

Contact :

Lionel DUBOIS

CEA - DSM/INAC/SyMMES/CAMPE

04 38 78 92 57

Thesis supervisor :

Patrick BERTHAULT

CEA - DRF/IRAMIS/NIMBE/LSDRM

+33 1 69 08 42 45

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

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

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



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



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

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

SL-DRF-18-0444

Research field : Chemistry
Location :

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

Laboratoire de Chimie Moléculaire et de Catalyse pour l'Energie (LCMCE)

Saclay

Contact :

Thibault CANTAT

Starting date : 01-10-2018

Contact :

Thibault CANTAT

CEA - DRF/IRAMIS/NIMBE/LCMCE

01 69 08 43 38

Thesis supervisor :

Thibault CANTAT

CEA - DRF/IRAMIS/NIMBE/LCMCE

01 69 08 43 38

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

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

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

Innovative Porous Materials for Glycomic Analysis in Hospitals

SL-DRF-18-0235

Research field : Chemistry
Location :

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

Laboratoire Edifices Nanométriques (LEDNA)

Saclay

Contact :

Laurent MUGHERLI

Martine Mayne

Starting date : 01-10-2018

Contact :

Laurent MUGHERLI

CEA - DRF/IRAMIS/NIMBE/LEDNA

0169089427

Thesis supervisor :

Martine Mayne

CEA - DRF/IRAMIS/NIMBE/LEDNA

01 69 08 48 47

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

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

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

Out-of-equilibrium thermoelectric transport in quantum conductors

SL-DRF-18-0459

Research field : Mesoscopic physics
Location :

Service de Physique de l'Etat Condensé (SPEC)

Groupe Mésocopie Modélisation et Thermoélectricité (GMT)

Saclay

Contact :

Geneviève FLEURY

Alexander SMOGUNOV

Starting date : 01-10-2017

Contact :

Geneviève FLEURY

CEA - DRF/IRAMIS/SPEC/GMT

0169087347

Thesis supervisor :

Alexander SMOGUNOV

CEA - DRF/IRAMIS/SPEC/GMT

0169083032

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

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

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



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



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

Quantum heat transport in graphene Van der Waals heterostructures

SL-DRF-18-0412

Research field : Mesoscopic physics
Location :

Service de Physique de l'Etat Condensé (SPEC)

Groupe Nano-Electronique (GNE)

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).

DNA compaction induced by a bacterial amyloid

SL-DRF-18-0270

Research field : Molecular biophysics
Location :

Laboratoire Léon Brillouin (LLB)

Groupe Biologie et Systèmes Désordonnés

Saclay

Contact :

Véronique ARLUISON

Starting date : 01-09-2018

Contact :

Véronique ARLUISON

Université Paris VII - DRF/IRAMIS/LLB/GBSD

01 69 08 32 82

Thesis supervisor :

Véronique ARLUISON

Université Paris VII - DRF/IRAMIS/LLB/GBSD

01 69 08 32 82

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

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

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

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

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

Electrochemical microscopy investigation of the multiphasic transport within an electrocatalytique layer

SL-DRF-18-0442

Research field : Physical chemistry and electrochemistry
Location :

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

Laboratoire Innovation, Chimie des Surfaces Et Nanosciences (LICSEN)

Saclay

Contact :

Renaud CORNUT

Bruno JOUSSELME

Starting date : 01-09-2018

Contact :

Renaud CORNUT

CEA - DRF/IRAMIS/NIMBE/LICSEN

01 69 08 91 91

Thesis supervisor :

Bruno JOUSSELME

CEA - DRF/IRAMIS/NIMBE/LICSEN

0169089191

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.

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

SL-DRF-18-0221

Research field : Radiation-matter interactions
Location :

Service Laboratoire Interactions, Dynamique et Lasers (LIDyL)

Attophysique (ATTO)

Saclay

Contact :

Thierry RUCHON

Starting date : 01-09-2018

Contact :

Thierry RUCHON

CEA - DRF/IRAMIS/LIDyL/ATTO

0169087010

Thesis supervisor :

Thierry RUCHON

CEA - DRF/IRAMIS/LIDyL/ATTO

0169087010

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

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

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



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



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

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

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

SL-DRF-18-0424

Research field : Radiation-matter interactions
Location :

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

Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire (LIONS)

Saclay

Contact :

Sophie LE CAER

Starting date : 01-09-2018

Contact :

Sophie LE CAER

CNRS - DRF/IRAMIS/NIMBE/LIONS

01 69 08 15 58

Thesis supervisor :

Sophie LE CAER

CNRS - DRF/IRAMIS/NIMBE/LIONS

01 69 08 15 58

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

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

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



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

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

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



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

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

SL-DRF-18-0432

Research field : Radiation-matter interactions
Location :

Service Laboratoire Interactions, Dynamique et Lasers (LIDyL)

Physique à Haute Intensité (PHI)

Saclay

Contact :

Henri VINCENTI

Guy BONNAUD

Starting date : 01-10-2018

Contact :

Henri VINCENTI

CEA - DRF/IRAMIS/LIDyL/PHI

0169080376

Thesis supervisor :

Guy BONNAUD

CEA - DRF/IRAMIS/LIDyL/PHI

0169088140

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

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

More : https://www.picsar.net

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



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



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

Dissipation, cascades and singularities in turbulence

SL-DRF-18-0272

Research field : Soft matter and complex fluids
Location :

Service de Physique de l'Etat Condensé (SPEC)

Systèmes Physiques Hors-équilibre, hYdrodynamique, éNergie et compleXes (SPHYNX)

Saclay

Contact :

Bérengère DUBRULLE

Starting date : 01-10-2017

Contact :

Bérengère DUBRULLE

CNRS - DRF/IRAMIS/SPEC/SPHYNX

0169087247

Thesis supervisor :

Bérengère DUBRULLE

CNRS - DRF/IRAMIS/SPEC/SPHYNX

0169087247

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

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

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



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



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

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

Materials Synthesis and Integration in Water Quality Monitoring Sensors

SL-DRF-18-0286

Research field : Soft matter and complex fluids
Location :

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

Laboratoire Innovation, Chimie des Surfaces Et Nanosciences (LICSEN)

Saclay

Contact :

Jean-Christophe GABRIEL

Starting date : 01-10-2018

Contact :

Jean-Christophe GABRIEL

CEA - DRF/IRAMIS/NIMBE/LICSEN

0438780257

Thesis supervisor :

Jean-Christophe GABRIEL

CEA - DRF/IRAMIS/NIMBE/LICSEN

0438780257

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

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

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

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



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

Biophysical and dynamical study of chromatin conformation during genome replication

SL-DRF-18-0276

Research field : Soft matter and complex fluids
Location :

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

Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire (LIONS)

Saclay

Contact :

Frédéric GOBEAUX

Patrick GUENOUN

Starting date : 01-11-2017

Contact :

Frédéric GOBEAUX

CEA - DRF/IRAMIS/NIMBE/LIONS

01 69 08 24 74

Thesis supervisor :

Patrick GUENOUN

CEA - DRF/IRAMIS/NIMBE/LIONS

01-69-08-74-33

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

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

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



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



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

Self-assembled metamaterials made by block copolymers

SL-DRF-18-0245

Research field : Soft matter and complex fluids
Location :

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

Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire (LIONS)

Saclay

Contact :

Patrick GUENOUN

Virginie PONSINET

Starting date : 01-11-2017

Contact :

Patrick GUENOUN

CEA - DRF/IRAMIS/NIMBE/LIONS

01-69-08-74-33

Thesis supervisor :

Virginie PONSINET

CNRS - Centre de Recherche Paul Pascal (CRPP)

+33(0)5 56 84 56 25

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

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

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

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

SL-DRF-18-0443

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

Service de Physique de l'Etat Condensé (SPEC)

Groupe Mésocopie Modélisation et Thermoélectricité (GMT)

Saclay

Contact :

Alexander SMOGUNOV

Starting date : 01-05-2018

Contact :

Alexander SMOGUNOV

CEA - DRF/IRAMIS/SPEC/GMT

0169083032

Thesis supervisor :

Alexander SMOGUNOV

CEA - DRF/IRAMIS/SPEC/GMT

0169083032

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

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

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



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

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

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

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

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

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

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

Hybrid carbon nanotube optoelectronic devices for silicon photonics

SL-DRF-18-0445

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

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

Laboratoire Innovation, Chimie des Surfaces Et Nanosciences (LICSEN)

Saclay

Contact :

Arianna FILORAMO

Starting date : 01-10-2018

Contact :

Arianna FILORAMO

CEA - DRF/IRAMIS/NIMBE/LICSEN

01-69-08-86-35

Thesis supervisor :

Arianna FILORAMO

CEA - DRF/IRAMIS/NIMBE/LICSEN

01-69-08-86-35

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

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

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





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

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

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

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

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

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

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

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

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

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

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

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

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

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

In operando study of ferrite - perovskite multiferroic encapsulated microstructures

SL-DRF-18-0351

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

Service de Physique de l'Etat Condensé (SPEC)

Laboratoire Nano-Magnétisme et Oxydes (LNO)

Saclay

Contact :

Antoine BARBIER

Starting date : 01-10-2018

Contact :

Antoine BARBIER

CEA - DRF/IRAMIS/SPEC/LNO

01.69.08.39.23

Thesis supervisor :

Antoine BARBIER

CEA - DRF/IRAMIS/SPEC/LNO

01.69.08.39.23

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

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

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

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

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

SL-DRF-18-0045

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

Service de Physique de l'Etat Condensé (SPEC)

Groupe Mésocopie Modélisation et Thermoélectricité (GMT)

Saclay

Contact :

Cyrille BARRETEAU

Starting date : 01-12-2017

Contact :

Cyrille BARRETEAU

CEA - DRF/IRAMIS/SPEC/GMT

+33(0)1 69 08 38 56

Thesis supervisor :

Cyrille BARRETEAU

CEA - DRF/IRAMIS/SPEC/GMT

+33(0)1 69 08 38 56

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

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

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

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

Exploring spin fluctuations in photosensitive molecules

SL-DRF-18-0416

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

Laboratoire Léon Brillouin (LLB)

Groupe Interfaces et Matériaux (GIM)

Saclay

Contact :

Gregory CHABOUSSANT

Starting date : 01-10-2018

Contact :

Gregory CHABOUSSANT

CNRS-UMR 12 - LLB - Laboratoire de Diffusion Neutronique

01 69 08 96 51

Thesis supervisor :

Gregory CHABOUSSANT

CNRS-UMR 12 - LLB - Laboratoire de Diffusion Neutronique

01 69 08 96 51

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

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

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



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



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

Water photo-electrolysis assisted by an internal potential

SL-DRF-18-0353

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

Service de Physique de l'Etat Condensé (SPEC)

Laboratoire Nano-Magnétisme et Oxydes (LNO)

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.

Epsilon-Near-Zero modes in metamaterials for optoelectronics

SL-DRF-18-0399

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

Service de Physique de l'Etat Condensé (SPEC)

Laboratoire d'Electronique et nanoPhotonique Organique (LEPO)

Saclay

Contact :

Simon VASSANT

Starting date : 01-10-2018

Contact :

Simon VASSANT

CEA - DRF/IRAMIS/SPEC/LEPO

+33 169 089 597

Thesis supervisor :

Simon VASSANT

CEA - DRF/IRAMIS/SPEC/LEPO

+33 169 089 597

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

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

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



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



Two approaches will be considered:

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

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



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

Tunable multicomponent supramolecular magnetic self-assembly for spintronics

SL-DRF-18-0337

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

Service de Physique de l'Etat Condensé (SPEC)

Laboratoire d'Electronique et nanoPhotonique Organique (LEPO)

Saclay

Contact :

Fabien SILLY

Starting date : 01-10-2018

Contact :

Fabien SILLY

CEA - DRF/IRAMIS/SPEC/LEPO

01 69 08 80 19

Thesis supervisor :

Fabien SILLY

CEA - DRF/IRAMIS/SPEC/LEPO

01 69 08 80 19

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

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

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

Theoretical description of non-linear processes in magnetic materials

SL-DRF-18-0364

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

Laboratoire des Solides Irradiés (LSI)

Laboratoire des Solides Irradiés (LSI)

Saclay

Contact :

Valérie VENIARD

Starting date : 01-10-2018

Contact :

Valérie VENIARD

CNRS - LSI/Laboratoire des Solides Irradiés

01 69 33 45 52

Thesis supervisor :

Valérie VENIARD

CNRS - LSI/Laboratoire des Solides Irradiés

01 69 33 45 52

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

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



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



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

Superparamagnetic transitions in 3D superlattices of magnetic nanocrystals

SL-DRF-18-0451

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

Service de Physique de l'Etat Condensé (SPEC)

Systèmes Physiques Hors-équilibre, hYdrodynamique, éNergie et compleXes (SPHYNX)

Saclay

Contact :

caroline RAEPSAET

Sawako NAKAMAE

Starting date : 01-10-2018

Contact :

caroline RAEPSAET

CEA - DRF/IRAMIS/SPEC/SPHYNX

0169082423

Thesis supervisor :

Sawako NAKAMAE

CEA - DRF/IRAMIS/SPEC/SPHYNX

0169087538

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

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



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



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



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



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

New electronic states in single crystals and thin films of iridates

SL-DRF-18-0419

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

Service de Physique de l'Etat Condensé (SPEC)

Laboratoire Nano-Magnétisme et Oxydes (LNO)

Saclay

Contact :

Jean-Baptiste MOUSSY

Dorothée COLSON

Starting date : 01-10-2018

Contact :

Jean-Baptiste MOUSSY

CEA - DRF/IRAMIS/SPEC/LNO

01-69-08-92-00

Thesis supervisor :

Dorothée COLSON

CEA - DRF/IRAMIS/SPEC/LNO

01 69 08 73 14

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

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

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

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



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



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



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



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

Magnetic properties of differently-shaped metal nanocrystals

SL-DRF-18-0336

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

Service de Physique de l'Etat Condensé (SPEC)

Laboratoire d'Electronique et nanoPhotonique Organique (LEPO)

Saclay

Contact :

Fabien SILLY

Starting date :

Contact :

Fabien SILLY

CEA - DRF/IRAMIS/SPEC/LEPO

01 69 08 80 19

Thesis supervisor :

Fabien SILLY

CEA - DRF/IRAMIS/SPEC/LEPO

01 69 08 80 19

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

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

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

ToughGlasses: Researching tomorrow’s glasses today

SL-DRF-18-0227

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

Service de Physique de l'Etat Condensé (SPEC)

Systèmes Physiques Hors-équilibre, hYdrodynamique, éNergie et compleXes (SPHYNX)

Saclay

Contact :

Cindy ROUNTREE

Starting date : 01-10-2018

Contact :

Cindy ROUNTREE

CEA - DRF/IRAMIS/SPEC/SPHYNX

+33 1 69 08 26 55

Thesis supervisor :

Cindy ROUNTREE

CEA - DRF/IRAMIS/SPEC/SPHYNX

+33 1 69 08 26 55

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

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

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

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



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



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



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



Some Relevant Publications:

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

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

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

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

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

DOI:10.1016/j.jnoncrysol.2015.02.005

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

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

Europhysics Letters, 113:38002 (February 2016).

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

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

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

Generation of hot electrons of plasmonic origin: Physics and applications

SL-DRF-18-0292

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

Service de Physique de l'Etat Condensé (SPEC)

Laboratoire d'Electronique et nanoPhotonique Organique (LEPO)

Saclay

Contact :

Ludovic DOUILLARD

Starting date : 01-10-2018

Contact :

Ludovic DOUILLARD

CEA - DRF/IRAMIS/SPEC/LEPO

01 69 08 36 26

Thesis supervisor :

Ludovic DOUILLARD

CEA - DRF/IRAMIS/SPEC/LEPO

01 69 08 36 26

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

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

Physics and applications of hot electrons of plasmonic origin



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



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



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



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



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

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



Laboratoire d’accueil CEA IRAMIS SPEC UMR 3680

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

Ecole doctorale Ondes et Matière, Univ. Paris Saclay.

Ultra low field Magnetic Resonance Imaging

SL-DRF-18-0386

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

Service de Physique de l'Etat Condensé (SPEC)

Laboratoire Nano-Magnétisme et Oxydes (LNO)

Saclay

Contact :

Claude FERMON

Starting date : 01-10-2018

Contact :

Claude FERMON

CEA - DRF/IRAMIS/SPEC/LNO

01 69 08 94 01

Thesis supervisor :

Claude FERMON

CEA - DRF/IRAMIS/SPEC/LNO

01 69 08 94 01

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



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

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

SL-DRF-18-0111

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

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

Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire (LIONS)

Saclay

Contact :

Sophie CHARTON

David CARRIÈRE

Starting date : 01-11-2018

Contact :

Sophie CHARTON

CEA - DEN/DMRC

+33 (0)4.66.79.62.29

Thesis supervisor :

David CARRIÈRE

CEA - DSM/IRAMIS/NIMBE

0169085489

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

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

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

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

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

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

SL-DRF-18-0439

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

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

Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire (LIONS)

Saclay

Contact :

Sophie LE CAER

Antoine THILL

Starting date : 01-10-2018

Contact :

Sophie LE CAER

CNRS - DRF/IRAMIS/NIMBE/LIONS

01 69 08 15 58

Thesis supervisor :

Antoine THILL

CEA - DSM/IRAMIS/NIMBE/LIONS

01 69 08 99 82

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

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

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

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

 

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