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PhD subjects

45 sujets IRAMIS

Dernière mise à jour :


• Additive manufacturing, new routes for saving materials

• Atomic and molecular physics

• Biotechnologies,nanobiology

• Chemistry

• Electrochemical energy storage incl. batteries for energy transition

• Health and environment technologies, medical devices

• Mesoscopic physics

• Numerical simulation

• Physical chemistry and electrochemistry

• Plasma physics and laser-matter interactions

• Radiation-matter interactions

• Radiobiology

• Soft matter and complex fluids

• Solid state physics, surfaces and interfaces

• Theoretical Physics

• Ultra-divided matter, Physical sciences for materials

 

Photocatalytic deoxygenation of fatty esters: towards the production of biosourced alcanes

SL-DRF-24-0431

Location :

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

Laboratoire de Chimie Moléculaire et de Catalyse pour l’Energie

Saclay

Contact :

Lucile ANTHORE

Starting date : 01-10-2024

Contact :

Lucile ANTHORE
CEA - DRF/IRAMIS/NIMBE/LCMCE

01 69 08 91 59

Thesis supervisor :

Lucile ANTHORE
CEA - DRF/IRAMIS/NIMBE/LCMCE

01 69 08 91 59

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

Laboratory link : https://iramis.cea.fr/Pisp/thibault.cantat/

Alkanes are essential molecules in the energy sector (fuels), as well as in specialty chemicals (cosmetics, adhesives, etc.) and fine chemicals. Today, they are mainly derived from non-renewable fossil resources, and their use contributes to climate change through the production of carbon dioxide. To achieve carbon neutrality, producing alkanes from renewable carbon sources such as biomass would appear to be an attractive alternative. In biomass, fatty esters of the RCO2R' type have long alkyl chains, but the presence of oxygen atoms means they are not a direct substitute for petroleum-based alkanes.

The aim of this thesis is to develop homogeneous catalytic systems for the photocatalytic deoxygenation of esters into the corresponding alkanes, by simple extrusion of a CO2 molecule. The energy required for the reduction reaction will be provided by light. Throughout this thesis project, the focus will be on developing catalytic systems and understanding reaction mechanisms through experimental studies (kinetics, NMR studies, observation of reaction intermediates, etc.) combined with theoretical chemistry (DFT calculations).
Fermionic-bosonic qubit

SL-DRF-24-0391

Location :

Service de Physique de l’Etat Condensé (SPEC)

Groupe Quantronique (GQ)

Saclay

Contact :

Hugues POTHIER

Starting date : 01-10-2024

Contact :

Hugues POTHIER
CEA - DRF/IRAMIS/SPEC/GQ

01 69 08 55 29

Thesis supervisor :

Hugues POTHIER
CEA - DRF/IRAMIS/SPEC/GQ

01 69 08 55 29

Personal web page : https://iramis.cea.fr/Pisp/hugues.pothier/

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

One of the most promising architectures in large-scale quantum information processing is the one based on superconducting electrodynamic (bosonic) qubits. They rely on an elementary device: the Josephson tunnel junction, a tunnel barrier between two superconducting leads, which exhibit nonlinear and non-dissipative behavior. Josephson tunnel junctions are only an example of superconducting weak links, among which are also atomic contacts and semiconducting nanowire weak links. In these other examples, localized, fermionic states, known as Andreev levels, can be addressed. We recently performed their spectroscopy [1-4] and quantum manipulation [5,6].

Here we propose to design, fabricate and measure new hybrid qubits that combine bosonic and fermionic degrees of freedom in the quest to realize more robust quantum states.

We are looking for a strongly motivated student having a good understanding of quantum physics. She/he will be integrated in an active research group on quantum electronics and get acquainted with advanced concepts of quantum mechanics and superconductivity. He/she will also learn several experimental techniques: low temperatures, low-noise and microwave measurements, and nanofabrication.



[1] L. Bretheau, Ç. Ö. Girit , H. Pothier , D. Esteve , and C. Urbina, “Exciting Andreev pairs in a superconducting atomic contact” Nature 499, 312 (2013). arXiv:1305.4091
[2] L. Tosi, C. Metzger, M. F. Goffman, C. Urbina, H. Pothier, Sunghun Park, A. Levy Yeyati, J. Nygård, P. Krogstrup, “Spin-Orbit Splitting of Andreev States Revealed by Microwave Spectroscopy”, Phys. Rev. X 9, 011010 (2019).
[3] C. Metzger, Sunghun Park, L. Tosi, C. Janvier, A. A. Reynoso, M. F. Goffman, C. Urbina, A. Levy Yeyati, H. Pothier, “Circuit-QED with phase-biased Josephson weak links”, Phys. Rev. Research 3, 013036 (2021).
[4] F. J. Matute Cañadas, C. Metzger, Sunghun Park, L. Tosi, P. Krogstrup, J. Nygård, M. F. Goffman, C. Urbina, H. Pothier, A. Levy Yeyati, “Signatures of interactions in the Andreev spectrum of nanowire Josephson junctions”, arXiv:2112.05625
[5] C. Janvier et al., “Coherent manipulation of Andreev states in superconducting atomic contacts” Science 349, 1199 (2015), arXiv:1509.03961
[6] C. Meztger, “Spin & charge effects in Andreev Bound States”, PhD thesis (2022)
4D printing of thermo-magnetic composite materials using light-driven additive manufacturing techniques

SL-DRF-24-0649

Research field : Additive manufacturing, new routes for saving materials
Location :

Laboratoire des Solides Irradiés (LSI)

Laboratoire des Solides Irradiés (LSI)

Saclay

Contact :

Giancarlo RIZZA

Starting date : 01-03-2024

Contact :

Giancarlo RIZZA
CEA - DRF/IRAMIS/LSI/LSI

01.69.33.45.10

Thesis supervisor :

Giancarlo RIZZA
CEA - DRF/IRAMIS/LSI/LSI

01.69.33.45.10

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

Laboratory link : https://portail.polytechnique.edu/lsi/fr/page-daccueil

More : https://www.linkedin.com/in/giancarlo-rizza-phd-48338410a/

This PhD research project explores the cutting-edge field of 4D printing, a field that integrates smart materials into additivemanufacturing processes. The aim is to create nanocomposite objects with multifunctional capabilities, enabling them to change shapeand properties in response to external stimuli.

In this PhD project, we will primarily focus on liquid crystal elastomers (LCEs) as the active matrix. LCEs are a versatile class ofprogrammable polymer materials that can undergo reversible deformation under various stimuli, such as light, heat, electric fields, andmagnetic fields, transitioning from disordered to oriented phases. Because of their actuation properties, LCEs are promising candidatesin applications like artificial muscles in medicine and soft robotics.

Consequently, the project's first objective is to devise a method for 3D printing LCE resins using light-driven printing processes, includingdigital light processing (DLP), direct ink writing (DIW), and two-photon polymerization. The project also explores the possibility of co-printing using two laser sources with different wavelengths. This will result in designed objects capable of programmed deformationsand reversibility. To further enhance the actuation capabilities of the LCE matrices, magnetic particles will be incorporated into thethermoresponsive LCE resin. Thus, the second objective of the project is to develop a strategy for self-assembling and spatiallyorienting embedded magnetic nanoparticles in LCE resins during light-driven printing processes (DLP, DIW, 2PP). Ultimately, the thirdobjective of this project is to combine these two strategies to create sophisticated multifunctional soft machines and devices suitable forcomplex environments. Experiments will follow an incremental trial-and-error research approach, with the aim of improving machinelearning models by designing purpose-built objects.

The envisioned research work can be summarized into the following macro-steps:
- Specification of target shape-changes depending on the multiple stimulation scenarios
- Selection of active particles, formulation of the LCE, and synthesis of the particles
- Development of hybrid additive manufacturing strategies with possible instrumentation
- Printing proofs-of concept and conducting mechanical and actuation tests
- Characterization of composite structures
- Development of simulation models
- Realization of a demonstrator (e.g., crawling robot, actuators for the automotive sector…)
In situ and real time characterization of nanomaterials by plasma spectroscopy

SL-DRF-24-0388

Research field : Atomic and molecular physics
Location :

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

Laboratoire Edifices Nanométriques (LEDNA)

Saclay

Contact :

Marc BRIANT

Yann LECONTE

Starting date : 01-10-2024

Contact :

Marc BRIANT
CEA - DRF/IRAMIS/NIMBE

01 69 08 53 05

Thesis supervisor :

Yann LECONTE
CEA - DRF/IRAMIS/NIMBE/LEEL

0169086496

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

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

The objective of this Phd is to develop an experimental device to perform in situ and real time elemental analysis of nanoparticles during their synthesis (by laser pyrolysis or flame spray pyrolysis). Laser-Induced Breakdown Spectroscopy (LIBS) will be used to identify the different elements present and to determine their stoichiometry.

Preliminary experiments conducted at LEDNA have shown the feasibility of such a project and in particular the acquisition of a LIBS spectrum of a single nanoparticle. Nevertheless, the experimental device must be developed and improved in order to obtain a better signal to noise ratio, to decrease the detection limit, to take into account the different effects on the spectrum (effect of nanoparticle size, complex composition or structure), to automatically identify and quantify the elements present.

In parallel, other information can be sought (via other optical techniques) such as the density of nanoparticles, the size or shape distribution.
Nano-object simulations in biological media

SL-DRF-24-0362

Research field : Biotechnologies,nanobiology
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 :

Yves BOULARD

Jean-Philippe RENAULT

Starting date : 01-09-2024

Contact :

Yves BOULARD
CEA - DRF/JOLIOT/I2BC/

+33 169083584

Thesis supervisor :

Jean-Philippe RENAULT
CEA - DRF/IRAMIS/NIMBE/LIONS

01 69 08 15 50

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

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

Understanding the non-specific or specific interactions between biomolecules and nanomaterials is key to the development of safe nanomedicines and nanoparticles. Indeed, adsorption of biomolecules is the first process occurring after the introduction of biomaterials into the human body, which controls their biological response. In this thesis, we will simulate the interface between nanosystems and biomolecules on a scale of a hundred nanometers, using the new exascale computing resources available at the CEA from 2025 (Jules Verne machine installed at the CCRT).
Novel membranes based on 2D nanosheets

SL-DRF-24-0510

Research field : Chemistry
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 : 01-03-2024

Contact :

Jean-Christophe Gabriel
CEA - DRF/IRAMIS/NIMBE/LICSEN

0676043559

Thesis supervisor :

Jean-Christophe Gabriel
CEA - DRF/IRAMIS/NIMBE/LICSEN

0676043559

Personal web page : https://iramis.cea.fr/Pisp/jean.gabriel/

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

More : https://iramis.cea.fr/nimbe/

This thesis project aims to exfoliate new nanostructured architectures based on two-dimensional inorganic phases. These nanostructures will be designed for filtration devices and tested using our microfluidic platform. The target application is water purification and the selective separation of metal ions. The doctoral student will interact with chemists, physicists and electrochemists in a real multidisciplinary environment, on a fundamental research subject directly connected to application needs. Thus, during his thesis, the student will be exposed to a multidisciplinary environment and brought to carry out experiments in various fields such as inorganic chemistry, physical chemistry, micro / nano-fabrication and nano-characterization methods. In In this context, this project should potentially lead to significant societal benefits.

For the realization of the latter, he will have access to a very wide and varied range of equipment ranging from optical microscopes to the latest generation synchrotron (ESRF), including field effect or electron microscopes and galvanostats.

This thesis is therefore an excellent opportunity for professional growth, both in terms of your knowledge and your skills.
Hyperpolarised, continuous-mode NMR based on parahydrogen and grafted catalysts

SL-DRF-24-0590

Research field : Chemistry
Location :

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

Laboratoire Structure et Dynamique par Résonance Magnétique (LCF)

Saclay

Contact :

Gaspard HUBER

Starting date : 01-10-2024

Contact :

Gaspard HUBER
CEA - DRF/IRAMIS/NIMBE/LSDRM

01 69 08 64 82

Thesis supervisor :

Gaspard HUBER
CEA - DRF/IRAMIS/NIMBE/LSDRM

01 69 08 64 82

Personal web page : https://iramis.cea.fr/Pisp/gaspard.huber/

Laboratory link : https://iramis.cea.fr/nimbe/

More : https://iramis.cea.fr/Pisp/104/stephane.campidelli.html

Nuclear Nuclear magnetic resonance (NMR) is a robust, non-invasive technique of analysis. It provides valuable information about chemical reactions, which can then be better characterised and optimised. However, NMR is poorly sensitive, and low-concentrated solutes, such as intermediates of reaction, may be unobservable by conventional NMR. One method known to drastically but temporarily increase the sensitivity of NMR is to create a hyperpolarised state in the system of nuclear spins, i.e. a polarisation much greater than that accessible with available magnetic fields. One hyperpolarisation method uses the specific properties of parahydrogen. A catalyst is required to add parahydrogen to a multiple bond or a metal.

The present thesis will investigate the combined contribution of (i) parahydrogen-based hyperpolarisation [1], (ii) the grafting of the appropriate catalyst onto nanoparticles [2], and (iii) a continuous analysis method [3] to detect and identify chemical intermediates, areas in which the laboratory has acquired experience. This subject involves a major investment in instrumentation, as well as skills in synthetic chemistry and NMR.

The thesis will be carried out at NIMBE, a joint CEA/CNRS unit at CEA Saclay. The hyperpolarised NMR and the synthesis will take place under the respective responsibility of Gaspard HUBER, from LSDRM, and Stéphane CAMPIDELLI, from LICSEN. These two NIMBE laboratories are located in nearby buildings.

References:
[1] Barskiy et al, Prog. Nucl. Magn. Reson. Spectrosc. 2019, 33, 114-115,.
[2] Hijazi et al., Org. Biomol. Chem., 2018, 16, 6767-6772.
[3] Carret et al., Anal. Chem. 2018, 90, 11169-11173.
Catalytic cleavage of C-O and C-N bonds applied to the transformation or reductive depolymerization of waste plastics

SL-DRF-24-0379

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

Saclay

Contact :

Jean-Claude Berthet

Starting date : 01-10-2024

Contact :

Jean-Claude Berthet
CEA - DRF/IRAMIS/NIMBE/LCMCE

01 69 08 60 42

Thesis supervisor :

Jean-Claude Berthet
CEA - DRF/IRAMIS/NIMBE/LCMCE

01 69 08 60 42

Personal web page : https://iramis.cea.fr/Pisp/thibault.cantat/JeanClaude_Berthet.php

Laboratory link : https://iramis.cea.fr/Pisp/thibault.cantat/research.php

More : https://iramis.cea.fr/nimbe/LCMCE/

The recycling and chemical recovery of plastics are necessary and crucialsteps to accelerate the transition to a circular economy and reduce the pollution associated with these materials.

The aim of this project is to develop catalytic systems for depolymerizing oxygenated and nitrogenous plastics into their monomers or derivatives (alcohols, amines, halides or even hydrocarbons). These methods, which enable the carbonaceous matter in polymers to be recovered under mild conditions in the form of chemical products useful to the chemical industry, are still underdeveloped and will, in the future, be virtuous processing routes for recycling certain plastics.

The aim of this doctoral project is to develop and use new metal molecular complexes (aluminium, zirconium, rare earths, etc.) and organic catalysts (boron-based), which

- are simple, inexpensive, recyclable and more selective than current catalysts (composed of iridium, ruthenium and boron), to depolymerize different types of plastics (polyesters, polycarbonates, polyurethanes and polyamides),
- allow, in the case of reductive catalysis, the use of hydrosilanes and hydroboranes, as well as the use of new reducing agents acting by transfer hydrogenation routes.

Finally, we will also consider the use of organic anhydrides to transform plastics into reactive organic compounds useful in organic chemistry.
Porous materials integrated into devices for glycomic analysis in hospitals.

SL-DRF-24-0442

Research field : Chemistry
Location :

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

Laboratoire Edifices Nanométriques (LEDNA)

Saclay

Contact :

Marc MALEVAL

Martine Mayne

Starting date : 01-10-2024

Contact :

Marc MALEVAL
CEA - DRF/IRAMIS/NIMBE/LEDNA

0169084933

Thesis supervisor :

Martine Mayne
CEA - DRF/IRAMIS/NIMBE

01 69 08 48 47

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

Laboratory link : https://iramis.cea.fr/NIMBE/LEDNA/

Glycomics involves identifying oligosaccharides (OS) present in a biological fluid as a source of biomarkers for diagnosing various pathologies (cancers, Alzheimer's disease, etc.). To study these OS, sample preparation involves 2 key phases, enzymatic cleavage (breaking the bond between OS and proteins) followed by purification and extraction (separation of OS and proteins). However, the materials currently used in the protocols impose numerous manual and time-consuming steps, incompatible with high-throughput analysis.

In this context, the LEDNA laboratory specialized in materials science has recently developed a sol-gel process for the manufacture of Hierarchical Porosity Monoliths (HPMs) in miniaturized devices. These materials have provided a proof of concept demonstrating their value for the second stage of glycomic analysis, i.e. the purification and extraction of oligosaccharides. The LEDNA is now looking to improve the first step, corresponding to enzymatic cleavage, which has become a limiting factor in the glycomics analysis process. Functionalization of porous materials, in particular HPMs, with enzyme would enable simple sample preparation in just a few hours with a single step.

The aim of this thesis is therefore to show that the use of porous materials with a dual function - catalytic and filtration - applied to the preparation of samples for glycomic analysis is a relevant means of simplifying and accelerating glycomic analysis, as well as employing them in hospital-related studies to identify new biomarkers of pathologies.

The research project will involve developing a device incorporating porous materials with catalytic and filtration functions. Several aspects will be addressed, ranging from the synthesis and shaping of these materials to characterization of their textural and physico-chemical properties. Particular emphasis will be placed on enzyme immobilization. The most promising prototype(s) will be evaluated in a glycomic analysis protocol, verifying the oligosaccharide profiles obtained from human biofluids (plasma, milk). Physico-chemical characterization will involve a variety of techniques (SEM, TEM, etc.), as well as characterization of porosity parameters (nitrogen adsorption, Hg porosimeter). Oligosaccharides will be analyzed by high-resolution mass spectrometry (mainly MALDI-TOF).

For this multidisciplinary thesis project, we are looking for a student chemist or physical chemist, interested in materials chemistry and motivated by the applications of fundamental research in the field of new technologies for health. The thesis will be carried out in two laboratories, LEDNA for the materials part and LI-MS for the use of materials in glycomics analysis. The research activity will be carried out at the Saclay research center (91).
Synthesis and properties of water-soluble graphene quantum dots

SL-DRF-24-0013

Research field : Chemistry
Location :

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

Laboratoire Innovation, Chimie des Surfaces Et Nanosciences (LICSEN)

Saclay

Contact :

Stéphane CAMPIDELLI

Starting date : 01-10-2024

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. We will focus on their solubilty in water in order to study potential applications in biology. This project will be developed in collaboration with Physicists so the candidate will work in a multidisciplinary environment.
In situ Magic Angle spinning NMR analysis of Li-ion batteries

SL-DRF-24-0325

Research field : Electrochemical energy storage incl. batteries for energy transition
Location :

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

Laboratoire d’étude des éléments légers (LEEL)

Saclay

Contact :

Magali GAUTHIER

Alan WONG

Starting date : 01-10-2024

Contact :

Magali GAUTHIER
CEA - DRF/IRAMIS/NIMBE/LEEL

01 69 08 45 30

Thesis supervisor :

Alan WONG
CNRS - DRF/IRAMIS/NIMBE/LSDRM


Personal web page : https://iramis.cea.fr/nimbe/Pisp/magali.gauthier/

Laboratory link : https://iramis.cea.fr/nimbe/LEEL/

In situ solid-state Nuclear Magnetic Resonance (ssNMR) is a valuable characterization tool to decipher the electrochemical phenomena during battery operation. However, the broad signal lineshapes acquired from the sample static condition often retrain from the full potential of ssNMR characterization. Ex situ ssNMR experiments, using Magic-Angle sample Spinning (MAS), are often necessary to interpret the in situ data. As in any ex situ characterizations, the analyses do not always represent the real electrochemistry because of unwanted artifacts from the ex situ sample preparation, i.e., cell dismantling and electrode separations. Consequently, in situ ssNMR applications have been limited. The PhD student will address this limitation by developing a spinning battery cell for acquiring high-resolution ssNMR data under MAS for in situ study, including a new method of spatially-resolved ssNMR spectroscopy. Combining in situ, MAS, and localized spectroscopy would lead to an unprecedented in situ ssNMR tool for deciphering fundamental insights into battery chemistry, which the student will emphasize by studying phenomena such as interfaces and dendrite formation in operating Li-ion batteries.
Development of dense and fluidized granular beds in microfluidic channels for healthcare applications

SL-DRF-24-0399

Research field : Health and environment technologies, medical devices
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 :

Florent Malloggi

Starting date : 01-10-2024

Contact :

Florent Malloggi
CEA - DSM/IRAMIS/NIMBE/LIONS

+3316908 6328

Thesis supervisor :

Florent Malloggi
CEA - DSM/IRAMIS/NIMBE/LIONS

+3316908 6328

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

Laboratory link : https://iramis.cea.fr/en/Pisp/lions/

The major public health problem of sepsis requires breakthrough technologies for ultra-fast diagnosis. Dense, fluidized granular beds are ideal systems for liquid-solid or gas-solid exchange processes. They are widely used in industry thanks to their high surface-to-volume ratio. Over the past decade, microfluidics and lab-on-a-chip have enabled numerous advances, particularly in biological sample preparation. We propose to develop a versatile microfluidic platform that will enable the creation of such dense, fluidized beds. We will first work on the incorporation of membranes into microchannels, drawing on the patented know-how developed in the laboratory. We will then study and characterize the granular beds, and finally test them for the detection of bacteria in biological samples. This work will be carried out in collaboration with our physicists (LEDNA) and biologist (LERI) partners at CEA Saclay.
Thermal transport in non-abelian quantum hall states of graphene

SL-DRF-24-0305

Research field : Mesoscopic physics
Location :

Service de Physique de l’Etat Condensé (SPEC)

Groupe Nano-Electronique (GNE)

Saclay

Contact :

François PARMENTIER

Starting date : 01-10-2024

Contact :

François PARMENTIER
CNRS - DRF/IRAMIS/SPEC/GNE

+33169087311

Thesis supervisor :

François PARMENTIER
CNRS - DRF/IRAMIS/SPEC/GNE

+33169087311

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

Laboratory link : https://iramis.cea.fr/SPEC/GNE/

More : https://nanoelectronicsgroup.com

Even-denominator states of the fractional quantum Hall effect (e.g. ??=5/2) are expected to host excitations that have non-abelian anyonic statistics, making them promising candidates for the realization of topological quantum computing [1]. While the demonstration of these non-abelian statistics has long been an extremely challenging endeavor, recent experiments in GaAs semiconductor heterostructures have shown that the edge thermal conductance of the ??=??/?? state is quantized in half-integer values of the thermal conductance quantum [2,3]. This half-integer quantization is known to be an universal signature of non-abelian statistics, including of Majorana fermions [4]. However, many of the suspected candidates for the ground state of ??=5/2 have complex edge structures exhibiting counterpropagating neutral modes, which can modify the edge thermal conductance and give them non-integer values similar to that of a non-abelian edge. A very recent experiment [3] has circumvented the issue by finding a way to separate the contributions of the different channels at the edge, confirming the existence of a non-abelian channel with half-integer quantized electrical and thermal conductance. The next obvious interrogation is whether this result is truly universal: does it hold for different material, and different even-denominator states?

In this project, we propose to address these questions by performing heat transport measurements in fractional quantum Hall states in bilayer graphene. Bernal-stacked bilayer graphene (BLG) has recently shown to host a large variety of robust even-denominator fractional quantum Hall states [5-8], both hole- and electron-type. This provides an excellent test-bed on which to probe the thermal conductance, as these fractions are expected to be described by different (possibly non-abelian) ground states; furthermore, the ability to apply electric displacement fields allows a further degree of control over the even-denominator states, which can be investigated in terms of heat transport.

This experimental project relies on ultra-low temperature, high magnetic field thermal transport [9] based on high sensitivity-sensitivity electrical measurements. We are looking for highly motivated candidates whoe are interested in all aspects of the project, both experimental (sample fabrication, low noise measurements, cryogenics) and theoretical.

[1] Nayak, et al., RMP 80, 1083 (2008) [2] Banerjee, et al., Nature 559, 205 (2018)
[3] Dutta, et al., Science 377, 1198 (2022) [4] Kasahara, et al., Nature 559, 227 (2018)
[5] Ki, et al., Nano Letters 14, 2135 (2014) [6] Li, et al., Science 358, 648 (2017)
[7] Zibrov, et al., Nature 549, 360 (2017) [8] Huang, et al., PRX 12, 031019 (2022)
[9] Le Breton, …, & Parmentier, PRL 129, 116803 (2022)
Numerical twin for the Flame Spray Pyrolysis process

SL-DRF-24-0402

Research field : Numerical simulation
Location :

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

Laboratoire d’étude des éléments légers (LEEL)

Saclay

Contact :

Yann LECONTE

Starting date : 01-10-2024

Contact :

Yann LECONTE
CEA - DRF/IRAMIS/NIMBE/LEEL

0169086496

Thesis supervisor :

Yann LECONTE
CEA - DRF/IRAMIS/NIMBE/LEEL

0169086496

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

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

Our ability to manufacture metal oxide nanoparticles (NPs) with well-defined composition, morphology and properties is a key to accessing new materials that can have a revolutionary technological impact, for example for photocatalysis or storage of energy. Among the different nanopowders production technologies, Flame Spray Pyrolysis (FSP) constitutes a promising option for the industrial synthesis of NPs. This synthesis route is based on the rapid evaporation of a solution - solvent plus precursors - atomized in the form of droplets in a pilot flame to obtain nanoparticles. Unfortunately, mastery of the FSP process is currently limited due to too much variability in operating conditions to explore for the multitude of target nanoparticles. In this context, the objective of this thesis is to develop the experimental and numerical framework required by the future deployment of artificial intelligence for the control of FSP systems. To do this, the different phenomena taking place in the synthesis flames during the formation of the nanoparticles will be simulated, in particular by means of fluid dynamics calculations. Ultimately, the creation of a digital twin of the process is expected, which will provide a predictive approach for the choice of the synthesis parameters to be used to arrive at the desired material. This will drastically reduce the number of experiments to be carried out and in consequence the time to develop new grades of materials
Advanced 3D-printed metallic bipolar plates for PEMFC application

SL-DRF-24-0244

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 :

Mélanie FRANCOIS

Bruno JOUSSELME

Starting date : 01-10-2024

Contact :

Mélanie FRANCOIS
CEA - DRF/IRAMIS/NIMBE/LICSEN

0169089191

Thesis supervisor :

Bruno JOUSSELME
CEA - DRF/IRAMIS/NIMBE/LICSEN

0169 08 91 91

Personal web page : https://iramis.cea.fr/nimbe/Phocea/Membres/Annuaire/index.php?uid=MF276647

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

To meet the increasing energy demand and diversify energy resources, fuel cells emerge as a promising solution. This Ph.D work aims to contribute to the development of Proton Exchange Membrane Fuel Cells (PEMFCs), with a specific focus on bipolar plates (BPs) which ensure gas distribution and current collection. The first objectives are to design and manufacture stainless steel BPs using 3D printing (SLM - Selective Laser Melting) and to develop organic and inorganic anticorrosion coatings. Multiple channel architectures will be designed and characterized, including in-situ assessments with membrane-electrode assemblies (MEAs). Coatings will also be characterized, particularly in terms of their corrosion resistance through polarization methods. In the second phase, the aim is to integrate the optimized BPs with MEAs and thoroughly study the performance of PEMFCs using electrochemical techniques to gain fundamental insights into the mechanisms that limit PEMFCs performance.
Hybrid solid electrolytes for "all-solid" batteries: Formulation and multi-scale characterization of ionic transport

SL-DRF-24-0634

Research field : Physical chemistry and electrochemistry
Location :

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

Laboratoire d’étude des éléments légers (LEEL)

Saclay

Contact :

Saïd Yagoubi

Thibault CHARPENTIER

Starting date : 01-10-2024

Contact :

Saïd Yagoubi
CEA - DRF/IRAMIS/NIMBE/LEEL

+ 33 1 69 08 42 24

Thesis supervisor :

Thibault CHARPENTIER
CEA - DRF/IRAMIS/NIMBE/LSDRM

33 1 69 08 23 56

Personal web page : http://iramis.cea.fr/Pisp/said.yagoubi/

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

More : http://iramis.cea.fr/nimbe/lsdrm/

Lithium-ion batteries, widely present in our daily lives, have revolutionized portable applications and are now used in electric vehicles. The development of new generations of batteries for future applications in transport and storing electricity from renewable sources is therefore vital to mitigating climate change. Lithium-ion technology is generally considered as the preferred solution for applications requiring high energy density, while sodium-ion technology is particularly attractive for applications requiring power.

However, the intrinsic instability of liquid electrolytes results in safety issues. Faced with the requirements concerning the environment and safety, solid-state batteries based on solid electrolytes can provide an effective solution while meeting battery energy storage needs. The barriers to overcome allowing the development of all-solid-state battery technology consist mainly in the research of new chemically stable solid electrolytes with good electrical, electrochemical and mechanical performance. For this goal, this thesis project aims to develop “polymer/polymer” and “ceramic/polymer” composite solid electrolytes with high performance and enhanced safety. Characterizations by electrochemical impedance spectroscopy (EIS) will be carried out in order to understand the cation dynamics (by Li+ or Na+) at the macroscopic scale in composite electrolytes, while the local dynamics will be probed using advanced techniques of Solid-state NMR (23Na / 7Li relaxation, 2D NMR, in-situ NMR & operando). Other characterization techniques such as X-ray and neutron diffraction, XPS, chronoamperometry, GITT ... will be implemented for a perfect understanding of the structure of electrolytes as well as aging mechanisms at the electrolyte / electrolyte and electrolyte/electrode interfaces of the all-solid battery.

Key words: composite solid electrolyte, all-solid-state battery, interfaces, multiscale characterization, dynamics of Li + and Na + ions, electrochemical performance, solid-state NMR, X-ray / neutron diffraction.
Ab initio simulation of catalysts for green chemistry

SL-DRF-24-0302

Research field : Physical chemistry and electrochemistry
Location :

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

Laboratoire Structure et Dynamique par Résonance Magnétique (LCF)

Saclay

Contact :

Rodolphe POLLET

Patrick BERTHAULT

Starting date : 01-10-2024

Contact :

Rodolphe POLLET
CEA - DRF/IRAMIS/NIMBE/LSDRM

01 69 08 37 13

Thesis supervisor :

Patrick BERTHAULT
CEA - DRF/IRAMIS/NIMBE/LSDRM

+33 1 69 08 42 45

Personal web page : https://iramis.cea.fr/Pisp/rodolphe.pollet/

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

Catalysis is today at the core of chemical industrial applications. For example, the conversion of nitrile to amide, which is relevant in pharmaceuticals, agrochemicals, synthetic chemistry and polymer chemistry, by hydration requires an efficient catalyst due to its slow kinetics. For environmental reasons, it is crucial to discover catalysts without transition metals, neither toxic nor corrosive, and cheap. One example of such catalyst is hydroxide choline.

During this thesis, the student will learn how to perform ab initio molecular dynamics simulations coupled with a method which can reconstruct the free-energy landscape of the hydration reaction for different aromatic nitriles in different in silico experimental conditions. He or she will also have to perform quantum chemistry calculations at a level that can describe all the required intra and intermolecular interactions. This theoretical approach has already been successfully used within our team to describe other chemical reactions in aqueous solution and will be applied to the innovative field of green chemistry.
Nanodiamond-based porous electrodes: towards photoelectrocatalytic production of solar fuels

SL-DRF-24-0426

Research field : Physical chemistry and electrochemistry
Location :

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

Laboratoire Edifices Nanométriques (LEDNA)

Saclay

Contact :

Jean-Charles ARNAULT

Hugues GIRARD

Starting date : 01-10-2024

Contact :

Jean-Charles ARNAULT
CEA - DRF/IRAMIS/NIMBE/LEDNA

01 68 08 71 02

Thesis supervisor :

Hugues GIRARD
CEA - DRF/IRAMIS/NIMBE/LEDNA

0169084760

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

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

Among nanoscale semiconductors, nanodiamonds (ND) have not been really considered yet for photoelectrocatalytic reactions in the energy-related field. This originates from the confusion with ideal monocrystalline diamond featuring a wide bandgap (5.5 eV) that requires a deep UV illumination to initiate photoreactivity. At the nanoscale, ND enclose native defects (sp2 carbon, chemical impurities such as nitrogen) that can create energetic states in the diamond’s bandgap decreasing the light energy needed to initiate the charge separation. In addition, the diamond electronic structure can be strongly modified (over several eV) playing on its surface terminations (oxidized, hydrogenated, aminated) which can open the door to optimized band alignments with the species to be reduced or oxidized. Combining these assets, ND becomes competitive with other semiconductors toward photoreactions. The aim of this PhD is to investigate the ability of nanodiamonds in reducing CO2 through photoelectrocatalysis. To achieve this goal, electrodes will be made from nanodiamonds with different surface chemistries (oxidized, hydrogenated and aminated), either using a conventional ink-type approach or a more innovative one that results in a porous material including nanodiamonds and a PVD-deposited matrix. Then, the (photo)electrocatalytic performances under visible illumination of these nanodiamond-based electrodes toward CO2 reduction will be investigated in terms of production rate and selectivity, in presence or not of a transition metal macrocyclic molecular co-catalyst.
Large-scale numerical modeling and optimization of a novel injector for laser-driven electron accelerators to enable their use for scientific and technological applications

SL-DRF-24-0353

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

Service Laboratoire Interactions, Dynamique et Lasers (LIDyL)

Physique à Haute Intensité (PHI)

Saclay

Contact :

Luca Fedeli

Henri VINCENTI

Starting date : 01-10-2024

Contact :

Luca Fedeli
CEA - DRF/IRAMIS/LIDyL/PHI

+33 1 69 08 19 59

Thesis supervisor :

Henri VINCENTI
CEA - DRF/IRAMIS/LIDyL/PHI

0169080376

Personal web page : https://iramis.cea.fr/LIDYL/Phocea/Pisp/index.php?nom=henri.vincenti

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

More : https://www.olcf.ornl.gov/2022/10/27/warpx-named-gordon-bell-prize-finalist/

Ultra-short, high-energy (up to few GeVs) electron beams can be accelerated over just a few centimeters by making an ultra-intense laser interact with a gas-jet, with a technique called “Laser Wakefield Acceleration” (LWFA). Thanks to their small size and the ultra-short duration of the accelerated electron beams, these devices are potentially interesting for a variety of scientific and technological applications. However, LWFA accelerators do not usually provide enough charge for most of the envisaged applications, in particular if a high beam quality and a high electron energy are also required.

The first goal of this thesis is to understand the basic physics of a novel LWFA injector concept recently conceived in our group. This injector consists of a solid target coupled with a gas-jet, and should be able to accelerate a substantially higher amount of charge with respect to conventional strategies, while preserving at the same time the quality of the beam. Large scale numerical simulation campaigns and machine learning techniques will be used to optimize the properties of the accelerated electrons. The interaction of these electron beams with various samples will be simulated with Monte Carlo code to assess their potential for applications such as Muon Tomography and radiobiology/radiotherapy. The proposed activity is essentially numerical, but with the possibility to be involved in the experimental activities of the team.

The PhD student will have the opportunity to be part of a dynamic team with strong national and international collaborations. They will also acquire the necessary skills to participate in laser-plasma interaction experiments in international facilities. Finally, they will acquire the required skills to contribute to the development of a complex software written in modern C++ and designed to run efficiently on the most powerful supercomputers in the world: the state-of-the-art Particle-In-Cell code WarpX (prix Gordon Bell en 2022). The development activity will be carried out in collaboration with the team led by Dr. J.-L. Vay at LBNL (US), where the candidate could have the opportunity to spend a few months during the thesis.
Implementation of a novel injector concept to boost the accelerated charge in laser-driven electron accelerators to enable their use for scientific and technological applications

SL-DRF-24-0352

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

Service Laboratoire Interactions, Dynamique et Lasers (LIDyL)

Physique à Haute Intensité (PHI)

Saclay

Contact :

Luca Fedeli

Henri VINCENTI

Starting date : 01-10-2024

Contact :

Luca Fedeli
CEA - DRF/IRAMIS/LIDyL/PHI

+33 1 69 08 19 59

Thesis supervisor :

Henri VINCENTI
CEA - DRF/IRAMIS/LIDyL/PHI

0169080376

Personal web page : https://iramis.cea.fr/LIDYL/Phocea/Pisp/index.php?nom=henri.vincenti

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

More : https://www.olcf.ornl.gov/2022/10/27/warpx-named-gordon-bell-prize-finalist/

Ultra-short, high-energy (up to few GeVs) electron beams can be accelerated over just a few centimeters by making an ultra-intense laser interact with a gas-jet, with a technique called “Laser Wakefield Acceleration” (LWFA). Thanks to their small size and the ultra-short duration of the accelerated electron beams, these devices are potentially interesting for a variety of scientific and technological applications. However, LWFA accelerators do not usually provide enough charge for most of the envisaged applications, in particular if a high beam quality and a high electron energy are also required. The goal of this thesis is to implement a novel LWFA injector concept in several state-of-the-art laser facilities, in France and abroad. This injector concept, recently conceived in our group, consists in a solid target coupled with a gas-jet, and should be able to accelerate a substantially higher amount of charge with respect to conventional strategies, while preserving at the same time the quality of the beam. The proposed activity is mainly experimental, but with the possibility to be involved in the large-scale numerical simulation activities that are needed to design an experiment and to interpret its results. The PhD student will have the opportunity to be part of a dynamic team with strong national and international collaborations. They will also acquire the necessary skills to participate in laser-plasma interaction experiments in international facilities. Finally, they’ll have the possibility to be involved in the numerical activities of the group, carried out on the most powerful supercomputers in the world with a state-of-the-art Particle-In-Cell code (WarpX, Gordon Bell prize in 2022).
Quantum fragmented states in frustrated magnets

SL-DRF-24-0371

Research field : Radiation-matter interactions
Location :

Laboratoire Léon Brillouin (LLB)

Groupe 3 Axes (G3A)

Saclay

Contact :

SYLVAIN PETIT

Starting date : 01-10-2024

Contact :

SYLVAIN PETIT
CEA - DRF/IRAMIS/LLB/NFMQ/

01 69 08 60 39

Thesis supervisor :

SYLVAIN PETIT
CEA - DRF/IRAMIS/LLB/NFMQ/

01 69 08 60 39

Personal web page : https://iramis.cea.fr/Pisp/sylvain.petit/

Laboratory link : https://iramis.cea.fr/LLB/NFMQ/

The last few decades of condensed matter research have seen the emergence of a rich new physics, based on the notion of "spin liquids". Interest in these new states of matter stems from the fact that they exhibit large-scale quantum entanglement, a property that is fundamental to quantum computation. By directly exploiting this notion of entanglement, a quantum computer would enable revolutionary approaches to certain classes of problems, compared with conventional computers.

The study of spin liquids is therefore a key technological issue, and the aim of this thesis project is to contribute to this fundamental research effort.
Attosecond high reprate spectroscopy of ultrafast photoemission of gases

SL-DRF-24-0345

Research field : Radiation-matter interactions
Location :

Service Laboratoire Interactions, Dynamique et Lasers (LIDyL)

Attophysique (ATTO)

Saclay

Contact :

Pascal SALIERES

Starting date : 01-10-2024

Contact :

Pascal SALIERES
CEA - DRF/IRAMIS/LIDyL/ATTO

0169086339

Thesis supervisor :

Pascal SALIERES
CEA - DRF/IRAMIS/LIDyL/ATTO

0169086339

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

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

More : http://attolab.fr/

Summary :
The student will develop attosecond spectroscopy techniques making use of the new high reprate Ytterbium laser sources. The ultrafast photoemission dynamics will be studied to reveal in real time the processes of electron scattering/rearrangement as well as electron-ion quantum entanglement, using the charged-particle coincidence techniques.

Detailed summary :
In recent years, there has been spectacular progress in the generation of attosecond (1 as=10-18 s) pulses, rewarded by the 2023 Nobel Prize [1]. These ultrashort pulses are generated from the strong nonlinear interaction of short intense laser pulses with gas jets [2]. A new laser technology based on Ytterbium is emerging, with stability 5 times higher and reprate 10 times higher than the current Titanium:Sapphire technology. These new capabilities represent a revolution for the field.
This opens new prospects for the exploration of matter at the electron intrinsic timescale. Attosecond spectroscopy thus allows studying in real time the quantum process of photoemission, shooting the 3D movie of electronic wavepacket ejection [3,4], and studying quantum decoherence resulting from, e.g., electron-ion entanglement [5].
The first objective of the thesis work is to develop on the ATTOLab laser platform the attosecond spectroscopies using the new Ytterbium laser sources. The second objective is to take advantage of charged particle coincidence techniques, enabled by the high reprate, to study the dynamics of photoemission and quantum entanglement with unprecedented precision.
The student will be trained in ultrafast optics, atomic and molecular physics, quantum optics, and will acquire a broad mastery of XUV and charged-particle spectroscopy techniques.

References :
[1] https://www.nobelprize.org/prizes/physics/2023/summary/
[2] Y. Mairesse, et al., Science 302, 1540 (2003)
[3] V. Gruson, et al., Science 354, 734 (2016)
[4] A. Autuori, et al., Science Advances 8, eabl7594 (2022)
[5] C. Bourassin-Bouchet, et al., Phys. Rev. X 10, 031048 (2020)
Attosecond dynamics of electrons and spins in 2D and 3D magnetic materials

SL-DRF-24-0246

Research field : Radiation-matter interactions
Location :

Service Laboratoire Interactions, Dynamique et Lasers (LIDyL)

Dynamique et Interactions en phase COndensée (DICO)

Saclay

Contact :

Romain GENEAUX

Starting date : 01-10-2024

Contact :

Romain GENEAUX
CEA - DRF/IRAMIS/LIDyL/DICO

0169087886

Thesis supervisor :

Romain GENEAUX
CEA - DRF/IRAMIS/LIDyL/DICO

0169087886

Personal web page : https://iramis.cea.fr/Pisp/romain.geneaux/

Laboratory link : https://iramis.cea.fr/LIDYL/DICO/

Attosecond science focuses on the study of dynamics in matter at ultimate timescales, using light pulses of attosecond (10-18 s) duration. Our laboratory has pioneered the development and use of these pulses to investigate the ultrafast response of matter. In particular, we operate several platforms dedicated to attosecond spectroscopy of solids.

During this PhD project, we will develop original attosecond experiments aimed at elucidating the dynamics of one of the most important and intriguing degree of freedom of solids: the spins of its electrons. This quantity is responsible for the magnetic properties of materials, with applications ranging from data storage devices to spintronic components. Typically, existing devices use electric currents to convey and manipulate information.
Here, we aim to answer one apparently simple question: can we use a laser field, instead of a current, to control the electronic spins of a solid? While this would have the concrete potential of orders-of-magnitude faster operation, answering this question first requires fascinating fundamental investigations. Indeed, the response of magnetic materials at optical frequencies – below 10 fs – is almost completely unknown to this day. We propose to address this problem by performing experiments that combine spin sensitivity and attosecond resolution for the first time. By carefully shaping attosecond pulses and using state-of-the art detection schemes, we aim to establish a technique called attosecond magnetic dichroism, which will reveal the spin response of materials on the timescale of the electric field of light. We will first focus on simple tridimensional ferromagnetic and antiferromagnetic systems, before evolving towards their bi-dimensional counterparts. Indeed, so-called 2D materials are expected to provide enhanced, or even fundamentally novel light-spin interactions. By understanding how light interacts with electronic spins in 2D, we will provide key elements towards the integration of future low-dimensionality spintronic components.

The student will acquire practical knowledge about experimental ultrafast optics and of time resolved spectroscopy of condensed matter, especially magnetic materials. He/she will become an expert in attosecond physics and technology, as well as acquire valuable skills in complex data acquisition and analysis.
Spin, Symmetries, Topology and Altermagnetism

SL-DRF-24-0370

Research field : Radiation-matter interactions
Location :

Laboratoire Léon Brillouin (LLB)

Groupe 3 Axes (G3A)

Saclay

Contact :

SYLVAIN PETIT

Paul McClarty

Starting date : 01-10-2024

Contact :

SYLVAIN PETIT
CEA - DRF/IRAMIS/LLB/NFMQ/

01 69 08 60 39

Thesis supervisor :

Paul McClarty
CNRS - DRF/IRAMIS/LLB


Personal web page : https://iramis.cea.fr/Pisp/sylvain.petit/

Laboratory link : https://iramis.cea.fr/llb/NFMQ/

The central topic of the thesis is a recently proposed form of matter called altermagnetism. In common with simple antiferromagnets these are magnetic materials supporting long-range magnetic order with no net moment. In simple antiferromagnets the up and down spin electronic bands are degenerate. But in altermagnets they are not. One way of thinking about these materials is that they are nonmagnetic in real space but magnetic in momentum space thus combining features of ferromagnets and antiferromagnets. These materials have generated a great deal of interest in the spintronics community. Roughly speaking this community has, for a long time, been interested in antiferromagnets that support spin currents because antiferromagnets are insensitive to stray fields and can support faster device switching than in typical ferromagnets. Altermagnets have the potential to realize the dreams of antiferromagnetic spintronics. At the same time, altermagnets are of fundamental interest in condensed matter physics. It turns out that altermagnetism is grounded in a peculiar type of symmetry breaking described by the theory of spin groups.

The goal of this thesis project is to extend our understanding of spin groups in condensed matter especially in the direction of altermagnetism and topological materials.

Catalysis using sustainaBle hOllow nanoreacTors wiTh radiaL pErmanent polarization

SL-DRF-24-0284

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 :

Pierre PICOT

Sophie LE CAER

Starting date : 01-10-2024

Contact :

Pierre PICOT
CEA - DRF/IRAMIS/NIMBE/LIONS/


Thesis supervisor :

Sophie LE CAER
CNRS - DRF/IRAMIS/NIMBE/LIONS

01 69 08 15 58

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

Laboratory link : https://iramis.cea.fr/NIMBE/LIONS/

The combined demands of increasing energy production and the need to reduce fossil fuels to limit global warming have paved the way for an urgent need for clean energy harvesting technologies. One interesting solution is to use solar energy to produce fuels. Thus, low-cost materials such as semiconductors have been intensively studied for photocatalytic reactions. Among them, 1D nanostructures hold promise due to their interesting properties (high specific and accessible surfaces, confined environments, better charge separation). Imogolite, a natural hollow nanotube clay belongs to this category. Although it is not directly photoactive in the visible light range (high band gap), it exhibits a permanent wall polarization due to its intrinsic curvature. This property makes it a potentially useful co-photocatalyst for charge separation. Moreover, this nanotube belongs to a family sharing the same local structure with different curved morphologies (nanosphere and nanotile). In addition, several modifications of these materials are possible (wall doping with metals, coupling with metal nanoparticles, functionalization of the internal cavity) allowing tuning band gap. The proof of concept (i.e., photocatalytic nanoreactor) was only obtained for the nanotube form.

This phD project aims to study the whole family (nanotube, nanosphere, and nanotile, with various functionalizations) as nanoreactors for reduction reactions of protons and CO2 triggered under irradiation.
2D materials under irradiation for tomorrow's functionalities

SL-DRF-24-0400

Research field : Radiation-matter interactions
Location :

Centre de recherche sur les Ions, les Matériaux et la Photonique (CIMAP)

Centre de recherche sur les Ions, les Matériaux et la Photonique (CIMAP)

Saclay

Contact :

Stéphane GUILLOUS

Clara GRYGIEL

Starting date : 01-10-2024

Contact :

Stéphane GUILLOUS
CEA - DRF/IRAMIS/CIMAP/CIMAP

02.31.45.48.88

Thesis supervisor :

Clara GRYGIEL
CEA - DSM/IRAMIS/CIMAP

+33 2 31 45 49 34

Personal web page : https://cv.archives-ouvertes.fr/grygiel-clara

Laboratory link : http://cimap.ensicaen.fr/

In view of the challenges posed by global warming, some fundamental research is focusing on optimizing the properties of materials for gas capture (e.g. CO2), filtration, desalination or the conversion of water to H2 by photocatalysis. Two-dimensional materials (graphene, MoS2, hBN, etc.) nanostructured by ion irradiation have recently shown unique and original properties to improve the efficiency of these processes. The introduction of surface modifications to these materials can be used to tailor their properties to specific requirements. Irradiation by fast heavy ions, such as those produced on the GANIL facility, or by low-energy ions produced on CIMAP's PELIICAEN device, induces surface modifications on the nanometric scale.

In this thesis, we propose to gain a better understanding of the processes involved in ion-beam structuration and the modification of 2D material properties as a function of the influence of different irradiation parameters on the local radiation-induced modifications.
Exploration of the energy deposition dynamic on short time scale with laser-driven electron accelerator in the context of the Flash effect in radiotherapy

SL-DRF-24-0351

Research field : Radiation-matter interactions
Location :

Service Laboratoire Interactions, Dynamique et Lasers (LIDyL)

Physique à Haute Intensité (PHI)

Saclay

Contact :

Gérard BALDACCHINO

Sandrine DOBOSZ DUFRÉNOY

Starting date : 01-10-2023

Contact :

Gérard BALDACCHINO
CEA - DRF/IRAMIS/LIDYL

01 69 08 57 02

Thesis supervisor :

Sandrine DOBOSZ DUFRÉNOY
CEA - DRF/IRAMIS/LIDyL/PHI

01.69.08.63.40

Personal web page : https://iramis.cea.fr/LIDYL/Phocea/Pisp/index.php?nom=gerard.baldacchino

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

More : https://iramis.cea.fr/LIDYL/Phocea/Pisp/index.php?nom=sandrine.dobosz

The objective of the thesis project is to analyze the physicochemical processes resulting from the extreme dose rates that can now be obtained in water with the ultra-short (fs) pulses of relativistic electrons produced by laser-plasma acceleration. Indeed, first measurements show that these processes are probably not equivalent to those obtained with longer pulses (µs) in the FLASH effect used in radiotherapy. To achieve this, we propose to analyze the dynamics of formation/recombination of the hydrated electron, an emblematic species of water radiolysis, to qualify and quantify the dose rate effect over increasingly shorter times. This will be done in three stages in support of the necessary and now accessible technological progress, to have a dose per pulse sufficient to directly detect the hydrated electron. First, with the existing UHI100 facility, using the scavenging of the hydrated electron by producing a stable species; then producing a less stable but detectable species in real time and increasing the repetition rate of the electron source. Finally, by using an innovative concept named a “hybrid target”, based on a plasma mirror as an electron injector coupled to a laser-plasma accelerator, delivering larger doses with a narrower energy spectrum, we will be able to develop pump-probe detection allowing access to the shortest times, and to the formation in clusters of ionization, of the hydrated electron and measuring its initial yield.
Impact of LET on biological response to Flash irradiations

SL-DRF-24-0262

Research field : Radiobiology
Location :

Centre de recherche sur les Ions, les Matériaux et la Photonique (CIMAP)

Centre de recherche sur les Ions, les Matériaux et la Photonique (CIMAP)

Saclay

Contact :

François CHEVALIER

Gérard BALDACCHINO

Starting date : 01-10-2024

Contact :

François CHEVALIER
CEA - DRF/IRAMIS/CIMAP

02 31 45 45 64

Thesis supervisor :

Gérard BALDACCHINO
CEA - DRF/IRAMIS/LIDYL

01 69 08 57 02

Personal web page : https://cimap.ensicaen.fr/spip.php?article206

Laboratory link : https://cimap.ensicaen.fr/spip.php?rubrique113

Recent studies with electron and proton beams have shown that irradiation at dose rates above 40 Gy/s can be as effective in inhibiting tumor growth as irradiation at the conventional dose currently used (typically 1 Gy/min) but much less toxic to healthy tissues. This phenomenon is known as the “FLASH effect”. This effect is considered one of the most important discoveries in the recent history of radiobiology due to its potential to improve the therapeutic window between tumor control and normal tissue toxicity. Recent studies show that the biological mechanisms of the FLASH effect are linked to differential tissue oxygenation. However, the exact mechanisms of the cellular biological effects of FLASH irradiations are not completely clear and some are even contradictory.

The objective of this project is a molecular characterization of the FLASH effect on a model system perfectly controlled in vitro. FLASH irradiations of cancer cells and healthy cells will be compared to conventional dose rate irradiations using electrons and carbon ions in the two associated laboratories. The differential effect will be related to the oxygenation condition of the cells, REDOX/mitochondrial metabolism and general changes in cellular metabolism.
Experimental study of boundary layers in turbulent convection by Diffusive Waves Spectroscopy

SL-DRF-24-0355

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 :

Sébastien AUMAITRE

Starting date : 01-10-2024

Contact :

Sébastien AUMAITRE
CEA - DRF/IRAMIS/SPEC/SPHYNX


Thesis supervisor :

Sébastien AUMAITRE
CEA - DRF/IRAMIS/SPEC/SPHYNX


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

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

The aim of this thesis is to carry out the first experimental measurement of the energy dissipated in the boundary layers during turbulent convection in the Rayleigh-Bénard configuration. Indeed, some theories assert that this quantity controls the heat flux transported from the hot wall to the cold wall, while the efficiency of turbulent transport in convection is the subject of debate. Yet the properties of turbulent transport are essential to understanding the dynamics of climate and many astrophysical objects.

To estimate the energy dissipated, we need to be able to measure the norm of the velocity gradient. This quantity is difficult to access with conventional anemometry techniques, which measure velocity fields with limited resolution. These gradients are also expensive to obtain numerically over long time scales. But we have developed a technique for directly measuring the norm of velocity gradients using Multiple Scattering Spectroscopy. This will enable us to measure dissipative structures and the rate of energy dissipation in boundary layers.
Thermoelectric energy conversion in nanofluids for hybrid solar heat collector

SL-DRF-24-0358

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 :

Sawako NAKAMAE

Starting date : 01-10-2021

Contact :

Sawako NAKAMAE
CEA - DRF/IRAMIS/SPEC/SPHYNX

0169087538

Thesis supervisor :

Sawako NAKAMAE
CEA - DRF/IRAMIS/SPEC/SPHYNX

0169087538

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

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

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

Thermoelectric (TE) materials that are capable of converting heat into electricity have been considered as one possible solution to recover the low-grade waste-heat (from industrial waste-stream, motor engines, household electronic appliances or body-heat).

At SPHYNX, we explore thermoelectric effects in an entirely different class of materials, namely, complex fluids containing electrically charged nanoparticles that serve as both heat and electricity carriers. Unlike in solid materials, there are several inter-dependent TE effects taking place in liquids, resulting in Se values that are generally an order of magnitude larger that the semiconductor counterparts. Furthermore, these fluids are composed of Earth-abundant raw materials, making them attractive for future TE-materials that are low-cost and environmentally friendly. While the precise origins of high Seebeck coefficients in these fluids are still debated, our recent results indicate the decisive role played by the physico-chemical nature of particle-liquid interface.

The goal of the PhD project is two-fold :
- First, we will investigate the underlying laws of thermodynamic mechanisms behind the thermoelectric potential and power generation and other associated phenomena in nanofluids. More specifically, we are interested in how the particles' Eastman entropy of transfer is produced under the influence of thermal, electrical and concentration gradients. The results will be compared to their thermos-diffusive and optical abosrption properties to be obtained through research collaborations.
- Second, the project aims to test the promising nanofluids in the proof-of-concept hybrid solar-collector devices currently developed within the group to demonstrate the co-generation capability of heat and electricity. The hybrid device optimization is also within the project's scope

The proposed research project is primarily experimental, involving thermos-electrical, thermal and electrochemical measurements; implementation of automated data acquisition system and analysis of the resulting data obtained. The notions of thermodynamics, fluid physics and engineering (device) physics, as well as hands-on knowledge of experimental device manipulation are needed. Basic knowledge of optics and electrochemistry is a plus. For motivated students, numerical simulations using commercial CFD software, as well as the optical absorption measurements at the partner lab (LNO/CNR, Florence, Italy) can also be envisaged.
Dielectric response of a liquid far-from-equilibrium

SL-DRF-24-0279

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 :

Marceau HENOT

François LADIEU

Starting date : 01-09-2024

Contact :

Marceau HENOT
CEA - DRF/IRAMIS/SPEC/SPHYNX


Thesis supervisor :

François LADIEU
CEA - DRF/IRAMIS

01 69 08 72 49

Personal web page : https://iramis.cea.fr/Pisp/marceau.henot/

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

Materials in the glassy state are of great practical interest and can be found in many applications: silica glass as a construction or transport material, plastics which are generally at least partially glassy, or glassy metal alloys for advanced applications. However, the physical properties of these materials (e.g. the strength of a telephone screen) depend on the heat treatment they receive during their formation, and more specifically on the rate of cooling from the liquid state. While industrial glass manufacturing processes are obviously well mastered, the non-equilibrium thermodynamic nature of these systems makes it particularly difficult to investigate the physical mechanisms at work theoretically and numerically. This calls for an experimental approach aimed at probing these fundamental mechanisms.

The aim of this PhD thesis is to study experimentally the very non-equilibrium response of polar liquids, using a device recently developed in the laboratory which enables us to apply a very rapid temperature change to a liquid and follow its re-equilibration dynamics. Measurements of linear response should reveal more about the physical mechanisms governing equilibration, while non-linear measurements will provide information about the cooperative nature of structural rearrangements.
Multi-level functionality in ferroelectric, hafnia-based thin films for edge logic and memory

SL-DRF-24-0639

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

Service de Physique de l’Etat Condensé (SPEC)

Laboratoire d’Etude des NanoStructures et Imagerie de Surface (LENSIS)

Saclay

Contact :

NiCK BARRETT

Starting date : 01-10-2024

Contact :

NiCK BARRETT
CEA - DRF/IRAMIS/SPEC/LENSIS

0169083272

Thesis supervisor :

NiCK BARRETT
CEA - DRF/IRAMIS/SPEC/LENSIS

0169083272

Personal web page : https://iramis.cea.fr/Pisp/87/nick.barrett.html

Laboratory link : https://www.lensislab.com/

More : https://www.lensislab.com/projects

The numerical transition to a more attractive, agile and sustainable economy relies on research on future digital technologies.

Thanks to its non-volatility, CMOS compatibility, scaling and 3D integration potential, emerging memory and logic technology based on ferroelectric hafnia represents a revolution in terms of possible applications. For example, with respect to Flash, resistive or phase change memories, ferroelectric memories are intrinsically low power by several orders of magnitude.

The device at the heart of the project is the FeFET-2. It consists of a ferroelectric capacitor (FeCAP) wired to the gate of a standard CMOS transistor. These devices have excellent endurance, retention and power rating together with the plasticity required for neuromorphic applications in artificial intelligence.

The thesis will use advanced characterization techniques, in particular photoemission spectroscopy and microscopy to establish the links between material properties and the electrical performance of the FeCAPs.

Operando experiments as a function of number of cycles, pulse amplitude and duration will allow exploring correlations between the kinetics of the material properties and the electrical response of the devices.

The thesis work will be carried out in close collaboration with NaMLab (Dresden) and the CEA LETI (Grenoble).
Theoretical study of the physical and optical properties of some titanium oxide surfaces for greenhouse gas sensing applications

SL-DRF-24-0569

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

Laboratoire des Solides Irradiés (LSI)

Laboratoire des Solides Irradiés (LSI)

Saclay

Contact :

Nathalie VAST

Starting date : 01-10-2024

Contact :

Nathalie VAST
CEA - DRF/IRAMIS/LSI

01 69 33 45 51

Thesis supervisor :

Nathalie VAST
CEA - DRF/IRAMIS/LSI

01 69 33 45 51

Personal web page : http://nathalie-vast.fr

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

More : https://portail.polytechnique.edu/lsi/en/research/materials-science-theory

The international community is engaged in developing the policy to reduce greenhouse gases (GHGs) emission, in particular carbon dioxide (CO2), in order to reduce the risks associated to the global warming. Consequently, it is very important to find low-cost processes to dissociate and then capture carbon dioxide (CO2), as well as to develop low power, high performance sensors suitable to monitor GHGs reductions.A common and existing method for sensing the concentration of gases is achieved by using semiconducting metal oxides surfaces (MOS) like SnO2, ZnO, and TiO2. Moreover, one route to achieve CO2 dissociation is plasma assisted catalytic decomposition. However, surface defects, and in particular oxygen vacancies and charged trapped therein, play an important role in the (photo)reactivity of MOS. The way optical properties of surfaces are modified by such defects is not completely understood, nor is the additional effect of the presence of the gas. In some models, the importance of charge transfer is also emphasized.

In this Ph.D. work, theoretical methods will be used to model the surface with defects and predict the optical properties. The objective is threefold: To apply the theoretical frameworks developed at LSI for the study of defects to predict the defect charge states in bulk; To study the effect of the surface on the defect stability; to study bulk and surface optical properties, and find out spectroscopic fingerprints of the molecular absorption and dissociation near to the surface. Materials/gas under considerations are oxides like titanium oxide, eventually deposited on a layer on gold, and carbon dioxide. The theoretical method will be the time dependent density functional perturbation theory method (TDDFPT) developed at LSI in collaboration with SISSA, Trieste (Italy).

Ref.: I. Timrov, N. Vast, R. Gebauer, S. Baroni, Computer Physics Communications 196, 460 (2015).
Coupled electron and phonon dynamics in 1d and 2d materials for potential thermoelectric applications: quantum confinement and external phonon bath effects

SL-DRF-24-0535

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

Laboratoire des Solides Irradiés (LSI)

Laboratoire des Solides Irradiés (LSI)

Saclay

Contact :

Jelena SJAKSTE

Starting date : 01-10-2024

Contact :

Jelena SJAKSTE
CNRS - DRF/IRAMIS/LSI/LSI

+33169334511

Thesis supervisor :

Jelena SJAKSTE
CNRS - DRF/IRAMIS/LSI/LSI

+33169334511

Personal web page : https://www.polytechnique.edu/annuaire/sjakste-jelena

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

Today, in the context of climate change and the search for frugal numerical technologies, there is an urgent need to develop a portfolio of thermoelectric materials offering thermal stability, especially for the temperature range 300-400 K, where a large amount of heat is wasted into the environment. Compared to bulk materials, low-dimensional materials, such as nanowires and thin films, offer interesting possibilities for improvement of their thermoelectric properties. In this theoretical project, we aim to describe the coupled dynamics of hot electrons and phonons in low dimensional materials via an approach based on Density Functional Theory and on the solution of coupled Boltzmann transport equations for electrons and phonons. The focus of the project will be to describe main effects of reduced dimensionality and the role of interface and substrate on thermoelectric transport properties in 1D and 2D dimensional materials. The choice of materials is motivated by the potential applicability in the field of next generation energy harvesting, as well as by the ongoing collaborations with experimentalists. Recently, GEEPS researchers have demonstrated that 2D Bi2O2Se allows to achieve a thermoelectric power which is 6-fold larger and closer to room temperature operation than that measured recently by another team. This preliminary result is very encouraging and, at the same time, raises fundamental questions on the physical reasons which led to such outstanding power factor. This is what our theoretical project aims to elucidate.
Spin-current to charge-current interconversion devices: theoretical and experimental optimization of the efficiency

SL-DRF-24-0503

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

Laboratoire des Solides Irradiés (LSI)

Laboratoire des Solides Irradiés (LSI)

Saclay

Contact :

Jean-Eric WEGROWE

Starting date : 01-10-2024

Contact :

Jean-Eric WEGROWE
CEA - LSI/Laboratoire des Solides Irradiés

0169334555

Thesis supervisor :

Jean-Eric WEGROWE
CEA - LSI/Laboratoire des Solides Irradiés

0169334555

Personal web page : https://www.polytechnique.edu/annuaire/wegrowe-jean-eric

Laboratory link : https://portail.polytechnique.edu/lsi/fr/research/physique-et-chimie-des-nano-objets

The major argument for promoting the development of spin electronics is the low power dissipation. The aim of the thesis is to determine and optimize the power efficiency of these devices. We focus the study on the power dissipated by two kinds of devices. On the one hand, the devices allowing the reversal of the magnetization of a magnetic layer by a transverse spin current, namely the Spin-Orbit Torque effect (SOT), and on the other hand the devices based on topological materials.

In this context, the definition of useful power - or efficiency - is an open problem. Indeed, the thermodynamics of this type of non-equilibrium system involves cross-effects between the degrees of freedom of the electric charge carriers, those of the spin of these carriers, as well as those of the magnetization of the adjacent layer.

We have developed a variational method in order to establish the stationary state of a Hall bar and the power dissipated in a load circuit. Preliminary measurements have recently validated the prediction in the case of the anomalous Hall effect. The project aims to generalize the study to SOT and topological materials.

TeraHertz surface plasmonic resonators

SL-DRF-24-0344

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

Laboratoire des Solides Irradiés (LSI)

Laboratoire des Solides Irradiés (LSI)

Saclay

Contact :

Yannis Laplace

Starting date : 01-10-2024

Contact :

Yannis Laplace
Ecole Polytechnique - Laboratoire des Solides Irradiés LSI - UMR 7642

0169334512

Thesis supervisor :

Yannis Laplace
Ecole Polytechnique - Laboratoire des Solides Irradiés LSI - UMR 7642

0169334512

Personal web page : https://www.polytechnique.edu/annuaire/laplace-yannis

Laboratory link : https://portail.polytechnique.edu/lsi/fr/recherche/nouveaux-etats-electroniques/terax-lab

More : https://portail.polytechnique.edu/lsi/fr/recherche/nouveaux-etats-electroniques/

Scientific and technological development of the Terahertz (THz) frequency range, a domain of the electromagnetic spectrum that is located in between microwaves and infrared photonics, is timely and subjected to an intense research activity recently. We have recently developed TeraHertz cavities using a plasmonic mechanism based on the surface plasmons of a doped semiconductor. We have demonstrated the remarkable property of these resonators of being able to confine TeraHertz photons in record volumes of the order of 10-7 times smaller than the diffraction limit. This plasmonic mechanism also allows the functionalization and tunability of the cavities thanks to external parameters such as the electric or magnetic field or the temperature, among others. The aim of this thesis will be to develop THz plasmonic cavities and in particular to study their nonlinear behaviour when subjected to intense THz pulses. The aim will be to TeraHertz frequency conversion based on this nonlinearity.
Modelling point defects for quantum application including electron-lattice interaction and surface effect

SL-DRF-24-0570

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

Laboratoire des Solides Irradiés (LSI)

Laboratoire des Solides Irradiés (LSI)

Saclay

Contact :

Nathalie VAST

Starting date : 01-10-2024

Contact :

Nathalie VAST
CEA - DRF/IRAMIS/LSI

01 69 33 45 51

Thesis supervisor :

Nathalie VAST
CEA - DRF/IRAMIS/LSI

01 69 33 45 51

Personal web page : http://nathalie-vast.fr

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

More : https://portail.polytechnique.edu/lsi/en/research/materials-science-theory

The rise of room-temperature applications - nanoscale magnetometry, thermometry, single photon emission, solid-state implementation of qubits - of the negatively charged nitrogen-vacancy NV- center in diamond has motivated a renewed interest in the search, with theoretical methods, of other point defects - in diamond in another material- with a desired property for quantum application, e.g. a bright photoluminescence adna long coherence time of the spin ground state.

However, the fact that the local atomic structure of the defect ground-state or of the excited states is hardly accessible with direct experimental techniques prevents a direct understanding of the thermodynamics stability of defect charge states in the bulk, and of the expected quantum property. This makes the on-demand control of the defect charge state challenging, a problem even more complex near to the surface, because band bending induces a surface modification of the charge state and surface states of ubiquitous defects may be present.

In this Ph.D. work, theoretical methods will be used to predict the defect charge states and explore the effect of the proximity of the surface on the thermodynamic stability and on the spin structure. The objective is threefold: To apply the theoretical framework developed at LSI and predict the defect charge states in bulk; To study changes in the charge state brought by the proximity of the surface; To extend the Hubbard model used to compute the excited states and to account for the electron-lattice interaction in order to compute the zero-phonon line also for the excited states that cannot be predicted by the DFT only. Materials under considerations are carbides -diamond and silicon carbide- and borides - elemental boron and boron compounds. The theoretical method will rely on the Hubbard model developed at LSI in collaboration with IMPMC, and density functional theory (DFT) calculations.
Novel oxynitride based artificial multiferroic oxynitride thin films

SL-DRF-24-0474

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 : 01-10-2024

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 : https://iramis.cea.fr/Pisp/137/antoine.barbier.html

Laboratory link : https://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 multifunctional sensors. In this research field the search for new materials is particularly desirable because of unsatisfactory properties of current materials. The insertion of nitrogen in the crystal lattice of an oxide semiconductor allows in principle to modulate its electronic structure and transport properties enabling new functionalities. The production of corresponding single crystalline thin films is highly challenging. In this thesis work, single crystalline oxynitride heterostructures will be grown by atomic plasma-assisted molecular beam epitaxy. The heterostructure will combine two N doped layers: a N doped BaTiO3 will provide ferroelectricity and a heavily doped ferrimagnetic ferrite whose magnetic properties can be modulated using N doping to obtain new artificial multiferroic materials better suited to applications. The resulting structures will be investigated with respect to their ferroelectric and magnetic characteristics as well as their magnetoelectric coupling, 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, ferroelectric and magnetic characterizations as well as in state-of-the-art synchrotron radiation techniques.
Innovative concepts for particles plasma acceleration and radiation emission in laser – overdense plasma interaction at ultra-high intensity

SL-DRF-24-0638

Research field : Theoretical Physics
Location :

Laboratoire des Solides Irradiés (LSI)

Laboratoire des Solides Irradiés (LSI)

Saclay

Contact :

Michèle RAYNAUD

Starting date : 01-10-2024

Contact :

Michèle RAYNAUD
CEA - DRF/IRAMIS/LSI/LSI


Thesis supervisor :

Michèle RAYNAUD
CEA - DRF/IRAMIS/LSI/LSI


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

Laboratory link : https://portail.polytechnique.edu/lsi/fr/research/la-recherche-au-lsi

The present PHD work aims at exploring theoretically and numerically the generation of fast particle beams in ultra-relativistic (above 10^21 W/cm2) laser-overdense solid interaction by using properly-structured or shaped targets. Surface characteristics inducing local electromagnetic modes more intense than the laser field and where nonlinear and relativistic effects play a major role will be investigated.

On the basis of the work already carried out, the new scheme for particle acceleration will be extended in the ultra-relativistic regime of laser plasma interaction. It may 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.
Effect of substitution on the ferroelectric and photocatalytic properties of Barium Titanate nanoparticles

SL-DRF-24-0401

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

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

Laboratoire d’étude des éléments légers (LEEL)

Saclay

Contact :

Yann LECONTE

Starting date : 01-10-2024

Contact :

Yann LECONTE
CEA - DRF/IRAMIS/NIMBE/LEEL

0169086496

Thesis supervisor :

Yann LECONTE
CEA - DRF/IRAMIS/NIMBE/LEEL

0169086496

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

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

As part of the energy transition, the production of hydrogen from solar energy appears to be an extremely promising means of storing and then producing energy. To develop on a large scale, water photoelectrolysis requires materials with high catalytic efficiency. Among the candidates considered, materials derived from barium titanates appear promising because their ferro- and piezoelectric properties could increase their photocatalytic effect. Therefore, we propose to synthesize BaTiO3 nanoparticles by flame spray pyrolysis and to make substitutions on Ba and O in order to study the effect of these modifications on the ferroelectric properties of the material. The addition of noble metal inclusions to the surface of the particles, likely to improve catalysis, will also be addressed. Finally, photocatalysis and piezocatalysis tests will make it possible to establish the links between ferroelectric and catalytic phenomena in this family of materials. This subject will be carried out in collaboration between the LEEL of the CEA and the SPMS of Centrale – Supelec.
Structural evolution under electron irradiation of lamellar hydroxydes and hydrates

SL-DRF-24-0532

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

Laboratoire des Solides Irradiés (LSI)

Laboratoire des Solides Irradiés (LSI)

Saclay

Contact :

Marie-Noelle De Noirfontaine

Starting date : 01-10-2024

Contact :

Marie-Noelle De Noirfontaine
CNRS - DRF/IRAMIS/LSI


Thesis supervisor :

Marie-Noelle De Noirfontaine
CNRS - DRF/IRAMIS/LSI


Personal web page : https://www.polytechnique.edu/annuaire/de-noirfontaine-marie-noelle

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

The societal context of the study is the optimization of cementitious matrices for nuclear waste conditioning. These cementitious matrices are composed of hydrated minerals, some of which are lamellar (portlandite Ca(OH)2, brucite Mg(OH)2, brushite CaHPO4.2H2O, gibbsite Al(OH)3...). Very few data exist in the literature on the structural damage of these hydrated lamellar minerals under electron irradiation. The aim of the proposed thesis is to experimentally investigate irradiation-induced structural modifications in various types of compounds, with a view to gaining a better understanding of the damage mechanisms of these compounds under irradiation, and to identify irradiation sensitivity criteria in order to ultimately optimize the chemical and mineralogical composition of the materials.
Multiscale metamaterials based on 3D-printed biosourced polymer composites

SL-DRF-24-0326

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 :

Valérie GEERTSEN

Starting date : 01-10-2024

Contact :

Valérie GEERTSEN
CEA - DRF/IRAMIS/NIMBE/LIONS

0643360545

Thesis supervisor :

Valérie GEERTSEN
CEA - DRF/IRAMIS/NIMBE/LIONS

0643360545

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

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

Reducing the density of materials is one of the best ways to diminish our energy footprint. One solution is to replace massive materials by microlattices. Among these, random architecture structures inspired by bird bone structure offer the best advantages, with isotropic mechanical behavior and increased mechanical resistance, while meeting the challenges of the circular economy. These material-saving metamaterials are manufactured by 3D printing and can be compacted at the end of their life cycle. Among manufacturing technologies, UV polymerization of liquid organic resin or composite is the most promising. It produces mechanically resistant materials without generating manufacturing waste. It is also possible to include large quantities of bio-sourced fillers, reducing even further their environmental impact.

The PhD-thesis proposed here focuses on the development of polymeric nanocomposite microlattice structures from resin formulation to mechanical properties study (viscoelasticity, yield stress, fracture resistance) through printing and post-processing stages. From a more fundamental point of view, the aim is to study the link between the composition, shape and surface properties of the fillers on one hand, and the imprimability of the composite resine and the mechanical properties of the resulting metamaterial on the other hand. The thesis will focus on the study of cellulose-type fillers in nanoparticle, microparticle or fiber form. This multidisciplinary study bridges technology to science while producing data for a digital twin.
Custom synthesis of diamond nanoparticles for photocatalytic hydrogen production

SL-DRF-24-0432

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

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

Laboratoire Edifices Nanométriques (LEDNA)

Saclay

Contact :

Hugues GIRARD

Jean-Charles ARNAULT

Starting date : 01-10-2024

Contact :

Hugues GIRARD
CEA - DRF/IRAMIS/NIMBE/LEDNA

0169084760

Thesis supervisor :

Jean-Charles ARNAULT
CEA - DRF/IRAMIS/NIMBE/LEDNA

01 68 08 71 02

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

Laboratory link : https://iramis.cea.fr/NIMBE/LEDNA/

Our recent results show that nanodiamond can also act as a photocatalyst, enabling the production of hydrogen under solar illumination [1]. Despite its wide band gap, its band structure is adaptable according to its nature and surface chemistry [2]. Moreover, the controlled incorporation of dopants or sp2 carbon leads to the generation of additional bandgap states that enhance the absorption of visible light, as shown in a recent study involving our group [3]. The photocatalytic performance of nanodiamonds is therefore highly dependent on their size, shape and concentration of chemical impurities. It is therefore essential to develop a "tailor-made" nanodiamond synthesis method, in which these different parameters can be finely controlled, in order to provide a supply of "controlled" nanodiamonds, which is currently lacking.

The aim of this PhD is to develop a bottom-up approach to nanodiamond synthesis using a sacrificial template (silica beads or fibers) to which diamond seeds < 10 nm are attached by electrostatic interaction. The growth of diamond nanoparticles from these seeds will be achieved by exposing these objects to a microwave-enhanced chemical vapor deposition (MPCVD) growth plasma, allowing very fine control of (i) the incorporation of impurities into the material (ii) its crystalline quality (sp2/sp3 ratio) (iii) its size. This growth facility, which exists at the CEA NIMBE, is used for the synthesis of boron-doped diamond core-shells [4]. In the second part of the thesis, an innovative process (patent pending) is implemented to achieve MPCVD growth of diamond nanoparticles by circulating the sacrificial templates in a gas stream. During this work, different types of nanodiamonds will be synthesized: intrinsic nanoparticles (without intentional doping) and nanoparticles doped with boron or nitrogen.

After growth, the nanoparticles will be collected after dissolution of the template. Their crystal structure, morphology and surface chemistry will be studied at CEA NIMBE by scanning electron microscopy, X-ray diffraction and Raman, infrared and photoelectron spectroscopy. A detailed analysis of the crystallographic structure and structural defects will be carried out by high-resolution transmission electron microscopy.

Nanodiamonds will then be surface-modified to give them colloidal stability in water. Their photocatalytic performance for hydrogen production will be evaluated in collaboration with ICPEES (Strasbourg University).


References
[1] Patent, Procédé de production de dihydrogène utilisant des nanodiamants comme photocatalyseurs, CEA/CNRS, N° FR/40698, juillet 2022.
[2] Miliaieva et al., Nanoscale Adv. 2023.
[3] Buchner et al., Nanoscale (2022)
[4] Henni et al., Diam. Relat. mater. (under review)
Exploring the reactivity of oxide based catalysts by radiolysis

SL-DRF-24-0239

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

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

Laboratoire Edifices Nanométriques (LEDNA)

Saclay

Contact :

Nathalie HERLIN

Sophie LE CAER

Starting date : 01-10-2024

Contact :

Nathalie HERLIN
CEA - DRF/IRAMIS/NIMBE/LEDNA

0169083684

Thesis supervisor :

Sophie LE CAER
CNRS - DRF/IRAMIS/NIMBE/LIONS

01 69 08 15 58

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

Laboratory link : https://iramis.cea.fr/nimbe/LIONS

More : https://iramis.cea.fr/nimbe/LEDNA

In the context of the search for processes that are less polluting and more energy-efficient than current processes, it is interesting to produce high-stake molecules such as C2H4 by developing alternative synthesis routes to steam cracking, which is used in the majority of cases, but is energy-intensive and based on fossil resources. Processes such as photocatalysis, which relies on the use of light energy, seem an attractive way of generating these molecules of interest. In this context, we have already shown that the use of TiO2-based photocatalysts decorated with copper particles enables the production of ethylene from an aqueous solution of propionic acid, with a selectivity (C2H4/other carbonaceous products) of up to 85%.

However, photocatalysis kinetics can be slow, and it can take a long time to identify the best catalysts or catalyst/reagent pairs for a given reaction. So, in order to determine whether radiolysis, which relies on the use of radiation to ionize matter, can be an effective method of screening catalysts, initial experiments have already been carried out on catalyst (TiO2 or Cu TiO2)/reagent (propionic acid more or less concentrated) pairs, previously studied in photocatalysis. Initial results obtained by radiolysis are encouraging. In these experiments, only dihydrogen production was measured. A significant difference was observed in this production depending on the system: it was high during radiolysis of propionic acid with TiO2 nanoparticles, and significantly lower in the presence of Cu TiO2 nanoparticles, suggesting a different reaction path in the latter case, in line with observations made during photocatalysis experiments.

The aim of this thesis work will be to extend these initial results by synthesizing nanoparticles (catalysts), preparing reagent/catalyst mixtures, then irradiating them and measuring the various gases produced by gas-phase micro-chromatography, with special attention on ethylene. Particular attention will be paid to determining the species formed, especially transient ones, in order to ultimately propose reaction mechanisms accounting for the differences observed for the different reagent/catalyst pairs. Comparisons will also be made with results obtained by photocatalysis.
Raw earth soil, an age-old material with new emerging uses

SL-DRF-24-0360

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 :

Jean-Philippe RENAULT

Diane REBISCOUL

Starting date : 01-09-2024

Contact :

Jean-Philippe RENAULT
CEA - DRF/IRAMIS/NIMBE/LIONS

01 69 08 15 50

Thesis supervisor :

Diane REBISCOUL
CEA - DES/ICSM (DES)//L2ME

0033 4 66 33 93 30

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

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

More : https://www.icsm.fr/index.php?pagendx=3898

Raw earth materials, which have found multiple uses for millennia, now offer considerable potential for helping to adapt to the changing climate, thanks to their natural ability to regulate heat and water, as well as their low-CO2 production and shaping. However, scientific advances are still needed to get a more precise understanding of these materials, up to the nanometric scale.

This thesis focuses on the link between the mechanical properties of raw earth soil materials and their nanostructure, emphasizing the roles of confined water, ions and organic substances. Two approaches, based on the expertise on nanoporous media developed at CEA, Saclay and Marcoule, will be followed: the analysis of old materials using spectroscopic and radiation scattering methods, and the development of a screening protocol to identify physicochemical parameters important for durability. This research, which ultimately aims to optimize the formulation of raw earth materials, will be carried out in collaboration with architects specialists in the field.

 

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