Publications

2025

• Electron charge dynamics and charge separation: A response theory approach
  
  • Lacombe Lionel
  • Reining Lucia
  • Gorelov Vitaly
  SciPost Physics, SciPost Foundation, 2025. This study applies response theory to investigate electron charge dynamics, with a particular focus on charge separation. We analytically assess the strengths and limitations of linear and quadratic response theories in describing charge density and current, illustrated by a model that simulates charge transfer systems. While linear response accurately captures optical properties, the quadratic response contains the minimal ingredients required to describe charge dynamics and separation. Notably, it closely matches exact time propagation results in some regime that we identify. We propose and test several approximations to the quadratic response and explore the influence of higher-order terms and the effect of an on-site interaction $U$. (10.48550/arXiv.2508.14551)
  DOI : 10.48550/arXiv.2508.14551
• Impact of the silica glass initial state on the thermal and structural properties of metamict-like silica glass
  
  • Shchedrina N.
  • Lancry M.
  • Charpentier T.
  • Neuville D.
  • Ollier N.
  Journal of Non-Crystalline Solids, Elsevier, 2025, 655. This study investigates the structural and thermal stability of metamict-like silica glass samples prepared through different thermomechanical pathways and then subjected to the same high dose of electron irradiation (11 GGy). Specifically, we compared Suprasil F300 silica glass samples treated with high-pressure high-temperature (HPHT) conditions followed by irradiation to those solely irradiated. Additionally, Suprasil CG samples were analyzed to investigate the effect of silica impurities (e.g. OH) on the resulting state. Using Raman and FTIR spectroscopy, along with photoluminescence spectroscopy, we analyzed the vibrational structure and point defects changes. The activation energy distribution of the densification relaxation process was calculated to assess its thermal stability in a reliable manner. The results demonstrate that, despite achieving similar densities and vibrational structures in the metamict-like state, the initial structure of silica significantly influences the thermal stability and the resulting point defects population. (10.1016/j.jnoncrysol.2025.123463)
  DOI : 10.1016/j.jnoncrysol.2025.123463
• Ultrafast dynamics of hot carriers: Theoretical approaches based on real-time propagation of carrier distributions
  
  • Sjakste Jelena
  • Sen Raja
  • Vast Nathalie
  • Saint-Martin Jérôme
  • Ghanem Mohammad
  • Dollfus Philippe
  • Murphy-Armando Felipe
  • Kanasaki Junichi
  The Journal of Chemical Physics, American Institute of Physics, 2025, 162 (6), pp.061002. In recent years, computational approaches which couple density functional theory (DFT)-based description of the electron–phonon and phonon–phonon scattering rates with the Boltzmann transport equation have been shown to obtain the electron and thermal transport characteristics of many 3D and 2D semiconductors in excellent agreement with experimental measurements. At the same time, progress in the DFT-based description of the electron–phonon scattering has also allowed to describe the non-equilibrium relaxation dynamics of hot or photo-excited electrons in several materials, in very good agreement with time-resolved spectroscopy experiments. In the latter case, as the time-resolved spectroscopy techniques provide the possibility to monitor transient material characteristics evolving on the femtosecond and attosecond time scales, the time evolution of photo-excited, nonthermal carrier distributions has to be described. Similarly, reliable theoretical approaches are needed to describe the transient transport properties of devices involving high energy carriers. In this review, we aim to discuss recent progress in coupling the ab initio description of materials, especially that of the electron–phonon scattering, with the time-dependent approaches describing the time evolution of the out-of-equilibrium carrier distributions, in the context of time-resolved spectroscopy experiments as well as in the context of transport simulations. We point out the computational limitations common to all numerical approaches, which describe time propagation of strongly out-of-equilibrium carrier distributions in 3D materials, and discuss the methods used to overcome them. (10.1063/5.0245834)
  DOI : 10.1063/5.0245834
• Mössbauer study of synthetic and extracted brownmillerite from sulfate resisting Portland cements
  
  • Mériot Alexis
  • Diliberto Sébastien
  • Izoret Laurent
  • de Noirfontaine Marie‐noëlle
  • Courtial Mireille
  • Gauffinet Sandrine
  • Dunstetter Frédéric
  Journal of the American Ceramic Society, Wiley, 2025, 108 (6), pp.e20461. This study investigates the quantitative distribution of iron between the two crystallographic sites of brownmillerite isolated in a previous study from four sulfate resisting (SR) Portland cement clinkers. 57 Fe Mössbauer spectroscopy was combined with powder x‐ray diffraction (XRD) in order to determine the balance between Fe 3+ and Al 3+ ions in the tetrahedral and octahedral sites of the orthorhombic structure. Synthetic samples covering the whole composition range were studied for protocol validation. (10.1111/jace.20461)
  DOI : 10.1111/jace.20461
• Enhanced Lattice Coherences and Improved Structural Stability in Quadruple A‐Site Substituted Lead Bromide Perovskites
  
  • Cherasse Marie
  • Heshmati Niusha
  • Urban Joanna M
  • Ünlü Feray
  • Spencer Michael S
  • Frenzel Maximilian
  • Perfetti Luca
  • Mathur Sanjay
  • Maehrlein Sebastian F
  Small, Wiley-VCH Verlag, 2025, 21 (21), pp.2500977. Lead halide perovskites (LHPs) are promising materials for efficient photovoltaic devices; however, they often encounter limited structural stability and degradation problems that limit their technological potential. This study investigates a novel perovskite composition consisting of (Cs, MA, FA, GA)PbBr₃, abbreviated as (4cat)PbBr₃, to effectively enhance phase stability and optoelectronic characteristics. The spectroscopic data reveal improved structural order, electronic properties, and dynamic lattice response in a cubic phase, which is uniquely stabilized by the specific cation composition down to 80 K. Superior optoelectronic properties are verified by increased photoluminescence (PL) and 20-fold higher electron mobility, when compared to the single-cation composition, MAPbBr₃. Notably, the ultrafast Terahertz-induced Kerr effect (TKE) reveals a dominating 1.1 THz octahedral twist mode, also observed in MAPbBr₃, however with a doubled phonon coherence time in (4cat)PbBr₃ at 80 K. The observation of higher structural order in the 4-cation composition is thus reflected by the prolonged lattice coherences, indicating enhanced dynamic screening effects that can explain the improved optoelectronic properties of (4cat)PbBr₃. This study therefore sheds light on the influence of the A-site cation composition on the inorganic sublattice and its coherent dynamics, highly relevant to perovskite-based photovoltaic and optoelectronic technologies (10.1002/smll.202500977)
  DOI : 10.1002/smll.202500977
• Identification of paramagnetic species in silver-doped barium–germanium–gallium glass exposed to electron irradiation
  
  • Alassani Fouad
  • Petit Yannick
  • Cardinal Thierry
  • Ollier Nadège
  Journal of Applied Physics, American Institute of Physics, 2025, 137 (13), pp.013105. Ionizing irradiation was performed on barium-germanium-gallium (BGG) glasses using a 2.5 MeV electron beam. Through electron spin resonance spectroscopy, paramagnetic point defects, such as germanium-and gallium-related electron and hole trap centers, have been identified. The presence of silver in the BGG glass appears to hinder the stability of these defects at lower energy doses (10 4 Gy), with silver becoming the main trapping center. At higher energy doses (10 6 Gy), the glass undergoes structural modifications, hindering the trapping process of silver ions. Additionally, we evidence the importance of alkaline elements such as potassium and sodium on silver ions trapped centers' formation. (10.1063/5.0239091)
  DOI : 10.1063/5.0239091
• Dissipation properties of anomalous Hall effect: Intrinsic vs extrinsic magnetic materials
  
  • Desbuis V
  • Lacour D
  • Hehn M
  • Geiskopf S
  • Michez L
  • Rial J
  • Baltz Vincent
  • Wegrowe J-E
  Journal of Applied Physics, American Institute of Physics, 2025, 138, pp.233906. The power efficiency of Hall devices is still an open question. How is it possible to extract power from a current produced by the Hall effect? In what extent it is related to the nature of the effective magnetic field produced in the material? In order to answer these questions, a comparative study of anomalous-Hall current injection and anisotropic current injection (through planar Hall effect) are studied in Hall devices contacted to a lateral load circuit. Hall currents are injected into the load circuit from three different kinds of magnetic Hall bars: Mn 5 Si 3 altermagnet, Co 75 Gd 25 ferrimagnet, and Ni 80 Fe 20 ferromagnet. The current, the voltage and the power are measured as a function of the load resistance and the Hall angle. It is observed that the power dissipated for the three kinds of materials follow the same law as a function of load resistance and Hall angle, at the leading order in the Hall angle. Since the anomalous Hall effect in the altermagnetic Hall-bar is due to the intrinsic topological structure (i.e. due to the presence of a Berry phase in the reciprocal space), these observations suggest that the dissipative properties of anomalous Hall effect are dominated by the injection of electric charges accumulated at the edges, instead of the very mechanism responsible for it. (10.1063/5.0281311)
  DOI : 10.1063/5.0281311
• 1D nanoporous membrane boosts the ionic conductivity of electrolytes
  
  • Modesto Nino
  • Pinchart Camille
  • Abdel Sater Mohammad
  • Appel Markus
  • Fouquet Peter
  • Tengattini Alessandro
  • Russina Margarita
  • Grzimek Veronika
  • Günther Gerrit
  • Jouneau Pierre-Henri
  • Coasne Benoit
  • Lairez Didier
  • Judeinstein Patrick
  • Ramos Raphael
  • Gigmes Didier
  • Phan Trang N.T.
  • Berrod Quentin
  • Zanotti Jean-Marc
  Energy Storage Materials, Elsevier, 2025, pp.104045. (10.1016/j.ensm.2025.104045)
  DOI : 10.1016/j.ensm.2025.104045