Immobilization of molecular catalysts for CO2 conversion
Carbon dioxide, the main greenhouse gas, is also an abundant carbon resource that can be converted into value-added chemicals. Although CO2 reduction using hydrogen is a conventional approach, it remains energy-intensive due to the high dissociation energy of the H–H bond. An alternative strategy relies on the use of inorganic hydrides, such as hydrosilanes and hydroboranes, whose Si–H and B–H bonds are more readily activated. These compounds enable CO2 reduction under milder conditions through a homogeneous catalytic hydrosilylation step. To establish a sustainable cycle, the hydrides are regenerated electrochemically from silyl chlorides. With the aim of large-scale implementation and continuous operation, this PhD project focuses on the immobilization of molecular catalysts onto conductive surfaces. The objective is to functionalize these catalysts with anchoring groups in order to optimize their activity and increase the density of active sites. Various chemical and electrochemical strategies will be investigated. The modified catalysts will be grafted onto conductive supports and characterized using physicochemical and electrochemical techniques. Finally, the performance of the immobilized systems will be evaluated in terms of activity, selectivity, and stability, and compared with that of their homogeneous counterparts to identify the most efficient architectures for CO2 valorization.
Novel spin qubits for quantum computing
Quantum RAM (QRAM) is a key quantum computing resource featuring in many theoretical
proposals that has never been demonstrated in experiment. A QRAM is a quantum memory in which
one can read or write quantum information to a superposition of memory cells [1]. Such a device
is powerful as a tool for implementing a plethora of quantum algorithms, including Grover’s search
algorithm [2, 3], quantum chemistry [4, 5], quantum cryptography [6] and quantum machine learning
[7], and is regarded by many as essential for a future quantum computer. It has also proved difficult
to realise due to the complexity of implementing the quantum addressing of quantum storage [8, 9].
This PhD project will fit into a wider ongoing project to develop a QRAM using individual solid
state paramagnetic spin defects coupled to superconducting devices. The core aim of this project is
to investigate novel spin systems and device designs for the purposes of realising a scalable QRAM.
Novel high-gyromagnetic-ratio spin species will reach new regimes of spin-circuit coupling that were
previously inaccessible. The use of silicon as a substrate will allow future devices to reach higher
device quality factors and enable advanced device architectures by leveraging the maturity of silicon
device fabrication. High-spin nuclei such as 167Er will also be investigated, enabling experiments with
high-coherence nuclear spin qudits. These developments will expand the frontiers of a new hybrid
quantum device platform with exciting possibilities both for future quantum information processing
architectures and fundamental physics experiments
Developing a quantum router based on a hybrid spin superconducting circuit architecture
A QRAM is a quantum memory in which one can read or write quantum information to a superposition
of memory cells. Such a device is powerful as a tool for implementing a plethora of quantum
algorithms and is regarded by many as essential for a future quantum computer. It has also proved
di&cult to realise due to the complexity of implementing the quantum addressing of quantum
storage. This PhD work takes part in an e,ort aimed at using recently developed techniques in single
spin detection, spectroscopy and coherent control to demonstrate a quantum router, the unit cell of a
QRAM, using electron and nuclear spins in the solid state. The PhD work will consist of implementing
CSWAP gates schemes on Erbium defects in calcium tungstate in order to demonstrate a four-qubit
QRAM unit cell.
Orbitronics: time scales involved in orbital to charge conversion processes
Orbitronics is an emerging research field spanning condensed matter physics and materials science to electrical engineering that focuses on the study and manipulation of the electron's orbital angular momentum (OAM). The key idea is to use the OAM of electrons as a means to store, transfer, and process information, similar to how spintronics leverages the electron's spin. Importantly, OAM can be generated by a wide range of material systems and with theoretically much higher efficiency than its spin counterpart, using cheap, environmentally friendly and abundant lightweight elements. Orbitronics thus has both a fundamental interest and technological perspectives that provide an innovative and multidisciplinary framework.
Here, we are targeting oxide interfaces as a rich playground to explore Rashba physics in 2D electron gases (2DEG) and in particular its ability to confert spin or orbit to charge via the Orbital Inverse Rashba Edelstein effect. The LaAlO3/SrTiO3 interface provides an ideal playground to explore this physics and in particular parameters such as crystal orientation and the (LaAlO3) tunnel barrier. These properties will be studied at low-temperature as angular momentum is injected in the dc regime by the spin Seebeck effect. The study will be extended to the ultra-fast regime of the orbital to charge conversion using ultra-fast laser-induced demagnetization of a magnetic layer deposited on top and the measurement of the resulting THz emission. Here, we want to identify the parameters responsible for the decrease in efficiency at the picosecond timescale noted in the first THz emission measurements. Our final aim is to measure the timescales associated to hot electrons and spin/orbital diffusion in this system, which will be the main activity of the PhD student.
Measurement and modelling of the chemical activity of complex fluid components in hydrometallurgy
Modern extraction processes rely on the optimal use of complex fluids, the detailed understanding of which remains too empirical. To overcome this, new multi-scale simulation software packages are being developed, with one of the unknowns at the mesoscopic scale, where the aggregation of molecules, interface structures, etc. are not well understood. Chemical activity is key here, as it controls exchange and transfer processes. Understanding it allows these software packages to be validated. It must therefore be possible to measure and analyse it reliably for each component, particularly volatile ones. We proposed to do this by measuring their partial pressures. An initial version of a microfluidic device was developed and patented, which allows the partial pressures of volatile components to be measured simultaneously by infrared spectroscopy in a hollow waveguide. This experimental prototype device has been validated on simple systems. The aim of this thesis is to demonstrate the application potential of this unique tool for the simulation and rapid development of processes, focusing on important concrete cases, both from an experimental and modelling point of view. This type of study would be completely new and would make it possible to experimentally verify the stability predictions of complex fluids for the first time.
The PhD student will first need to update the microfluidic brick. He/she will then use it to measure the chemical activities of the aforementioned complex fluids and will work with Jean-François Dufrèche to test/validate/further develop the software packages. Secondly, at NTU in Singapore and under the co-supervision of Professor Alex Yan Qingyu (https://personal.ntu.edu.sg/alexyan/ ), he/she will use the duplicate microfluidic platform currently being assembled to apply these results to the rapid development of a process for extracting a critical metal from recycled electronic components from printed circuit boards (SCARCE joint laboratory).
Expected results: publications, proprietary software package and possible patents on the new processes developed.
In situ and real-time characterization of nanomaterials by plasma spectroscopy
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 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 increase 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.
Bottom-up synthesis of nanographene and study of their optical and electronic properties
This project is part of an ANR project, which aims to synthesize perfectly soluble and individualized graphene nanoparticles in solution and incorporate them into spin electronics devices. To do this, we will draw on the laboratory's experience in synthesizing and studying the optical properties of graphene nanoparticles to propose original structures to several groups of physicists who will be responsible for studying the optical and electronic properties and manufacturing spin valve-type devices.
Spatiotemporal shaping of high-order harmonic emission in nanostructured crystals
We propose to study the spatiotemporal manipulation of radiation emitted by high harmonic generation, leveraging advances in nanofabrication technologies. The approach involves transposing methods developed for meta-optics to the strong-field regime specific to harmonic generation. The candidate will explore various design strategies to control the spatiotemporal properties of this radiation, which is intrinsically linked to the broad spectral bandwidth of attosecond pulses. These concepts will then be implemented and experimentally validated. This project aims to enhance the integration of high harmonic generation into optoelectronic devices, paving the way for new applications in ultrafast photonics.
New concepts for cold neutron reflectors
The CEA and the CNRS have launched an initiative to design a new neutron source using low-energy proton accelerators, the ICONE project [1]. The goal is to build a facility that will provide an instrumental suite of about ten spectrometers available to the French and European scientific community. Alongside ICONE, the LLB is also participating in HiCANS R&D work on the construction of a platform in Bilbao to facilitate European collaborations.Neutron scattering experiments require thermal and cold neutrons. The design of the moderator is therefore a crucial component of the project to maximize the source's performance.
One avenue for improving the moderator performances is to enhance the efficiency of the reflector, and more specifically, the cold neutron reflector. In this study, we propose to investigate the specific scattering properties of cold neutrons on nanostructured materials. Indeed, cold neutrons have long wavelengths (> 0.4 nm) and can therefore be coherently scattered by nanostructured materials. Scattering efficiency is not only amplified by coherent scattering effects, but it is potentially possible to direct this scattering if the reflecting material is anisotropic. This control over the scattering direction can further increase the moderator's brightness.
The first part of the work will consist of identifying the most promising nanostructured materials and modeling their cold neutron reflectivity performance. In a second step, these materials will be shaped and their properties characterized using neutron scattering devices at neutron scattering facilities such as the ILL in Grenoble or the PSI in Switzerland.
CONTEXT: strain - texture neutron instrumentation for ICONE
The CEA and the CNRS have launched an initiative to design a new neutron source using low-energy proton accelerators, the ICONE project. The objective is to build a facility that will offer an instrumental suite of about ten spectrometers available to the French and European scientific community. The project is currently in the Preliminary Design phase, with the aim of refining as much as possible all technical aspects.
We are proposing a PhD thesis on the modeling and development of a new neutron scattering spectrometer for measuring textures and stresses in materials. This technique makes it possible to probe residual stresses in materials after machining, heat treatment, and/or use, and to measure the crystallographic anisotropy of alloys to exploit the induced mechanical properties.
Part of the work will take advantage of the start-up of the DREAM and MAGIC spectrometers at ESS in Sweden, in which the LLB participated in the construction, so that the candidate can become familiar with time-of-flight neutron scattering techniques (measurements and data analysis).
In the second part of this work, we propose to implement statistical modulation techniques for the construction of an instrument, CONTEXT, on ICONE, which will allow to best exploit the potential of ICONE's long pulses. The objective will be to create a digital twin of the future instrument using various Monte Carlo simulation tools.