Publications

2025

• Flexible piezoelectric energy harvester made of vertically-aligned ZnO nanowires hydrothermally-grown by template-assisted synthesis in poled PVDF
  
  • Sigallon Marie Clémence
  • Baillard Adrien
  • Consonni Vincent
  • Aubrit Florian
  • Potrzebowska Natalia
  • Grasset Romain
  • Tabellout Mohamed
  • Gogneau Noëlle
  • Sarrey Eliott
  • Wegrowe Jean-Eric
  • Clochard Marie-Claude
  Nano Trends, 2025, 10, pp.100112. The beneficial effect of the hydrothermal method on the morphology and piezoelectric performance of zinc oxide/polyvinylidene fluoride (ZnO/PVDF) composite thin membranes (10 μm-thick) is demonstrated. In this work, high aspect ratio vertically aligned ZnO nanowires were successfully grown on an Au seed layer to create a Schottky-like contact by template-assisted synthesis inside the cylindrical nanopores of a poled β-PVDF. Swift heavy ions irradiation was firstly used to create tracks of damages in this poled β-PVDF thin films. A subsequent chemical etching in alkaline medium revealed these ion-tracks to form dense and statistical arrays of cylindrical nanopores (10 9 pores cm -2 ) along its thickness. Resulting ZnO/PVDF composites were characterized by infrared spectroscopy, grazing incidence X-ray diffraction, scanning and transmission electron microscopy, atomic force microscopy, reflectance spectroscopy, dielectric measurements and piezoelectric analysis. Vertically aligned ZnO nanowires grown in low-supersaturation conditions exhibited an ideal microstructure for enhancing the piezoelectric performance of β-PVDF, i.e. hexagonal wurtzite structure. From piezoelectric analysis in bending mode, the output power of ZnO/PVDF composites was plotted against 8 resistances ranging from 10 5 to 10 6 Ω and fitted up to 10 8 Ω. A maximum power density of 1.90 μW cm -2 (i.e. 380 µW cm -3 N -1 ) at 2.10 6 Ω was found to be 60 ± 10 % higher than of pristine poled β-PVDF. The performance of these ZnO/PVDF composites may be due to the combined effects of Surface Fermi Level Pinning phenomenon, Schottky-like contact and dipole alignment. It thus reveals a very promising transducer in the renewable energy application of electromechanical energy conversion. (10.1016/j.nwnano.2025.100112)
  DOI : 10.1016/j.nwnano.2025.100112
• Al K -edge XANES of octahedral aluminum compounds: Similarities and differences via the analysis of excitonic properties
  
  • Amoyaw Newman
  • Agegnehu Abezu
  • Sottile Francesco
  • Gatti Matteo
  • Urquiza M. Laura
  Physical Review B, American Physical Society, 2025, 111 (16), pp.165112. <div><p>This study presents an ab initio investigation of the XANES spectra at the aluminum K edge for three compounds: Al2O3, AlF3 and AlCl3, where the Al atoms share the same oxidation state (III) and are coordinated in an octahedral symmetry. The XANES spectra calculated within the independent-particle approximation reveal significant differences, including shifts in the spectrum onset, variations in the spectral shapes, and the presence of a pre-peak in the case of AlCl3, all in correspondence with the behavior of the PDOS of the absorbing atom in the different materials. The origin of the features stems from the specific band structure of each compound. When electron-hole interactions are taken into account through the solution of the Bethe-Salpeter equation, a series of dark and bright excitons with large binding energies and Frenkel character is obtained. The strong excitonic effects lead to the suppression of the pre-peak in AlCl3 and further accentuate the differences among the three Al K-edge spectra.</p><p>I.</p></div> (10.1103/PhysRevB.111.165112)
  DOI : 10.1103/PhysRevB.111.165112
• Transient chaos in single crystal ferromagnetic membranes magneto-elastically driven by high-Q acoustic cavity modes
  
  • Vlasov V.
  • Golov A.
  • Pleshev D.
  • Kotov L.
  • Temnov Vasily
  Journal of Applied Physics, American Institute of Physics, 2025, 137 (13), pp.133904. Driving the nonlinear magnetization dynamics in freestanding (100) iron membranes in a perpendicular magnetic field by the lowest-order high-Q acoustic cavity mode at ∼10 GHz frequency is simulated by numerically solving the Landau–Lifshitz–Gilbert equations. The analysis of the large-amplitude magnetization precession within nanosecond time window displays the transient chaotic magnetization dynamics induced by hopping between metastable energy minima on a complex anisotropy landscape. Fingerprints of transient chaos should be observable in femtosecond magneto-acoustic experiments with finite acoustic lifetimes. (10.1063/5.0256528)
  DOI : 10.1063/5.0256528
• Structure et réactivité des matériaux cimentaires : apport de la cristallographie et de la diffraction des rayons X
  
  • de Noirfontaine Marie-Noëlle
  , 2025.
• 1D nanoporous membrane boosts the ionic conductivity of electrolytes
  
  • Modesto Nino
  • Pinchart Camille
  • Abdel Sater Mohammad
  • Judeinstein Patrick
  • Ramos Raphael
  • Coasne Benoit
  • Jouneau Pierre-Henri
  • Lairez Didier
  • Appel Markus
  • Fouquet Peter
  • Tengattini Alessandro
  • Russina Margarita
  • Grzimek Veronika
  • Günther Gerrit
  • Gigmes Didier
  • Phan Trang N.T.
  • Berrod Quentin
  • Zanotti Jean-Marc
  Energy Storage Materials, Elsevier, 2025, 75, pp.104045. Solid-state batteries have attracted significant interest as promising candidates for high energy density and safe battery technology. However, they commonly experience low ionic conductivity at ambient temperature, which limits their power density. This study addresses this issue by developing a porous separator with one-dimensional (1D) nanometric channels that confine non-flammable ionic liquid-based electrolytes. We achieve 1D macroscopic ionic transport by confining the electrolytes within Vertically Aligned Carbon NanoTubes (VA-CNT) composite membranes. Employing high-resolution quasi-elastic neutron scattering techniques, we conduct a multiscale analysis of the diffusive motion of both bulk and confined electrolytes. By extracting diffusion coefficients spanning from the molecular to macroscopic scale, we gain insights into the transport properties of the system. Our results demonstrate that nanometric confinement extends the operational temperature range of these electrolytes up to 20 K, towards lower values. At ambient temperature, we show a tenfold increase in conductivity under 1D CNT confinement. Molecular Dynamics simulations shed light on the underlying physics, showing a unique intermolecular organization of the ionic liquid under confinement. Specifically, the molecules form a cylindrical core-shell structure, resulting in the creation of quasi-1D transport channels. This study presents promising avenues for exploring the use of 1D materials in energy storage applications. (10.1016/j.ensm.2025.104045)
  DOI : 10.1016/j.ensm.2025.104045
• Short-range excitonic phenomena in low-density metals
  
  • Koskelo Jaakko
  • Reining Lucia
  • Gatti Matteo
  Physical Review Letters, American Physical Society, 2025, 134 (4), pp.046402. Excitonic effects in metals are commonly supposed to be weak, because the Coulomb interaction is strongly screened. We investigate the low-density regime of the homogeneous electron gas, where low-energy collective excitations and ghost modes were anticipated. Using the Bethe-Salpeter equation (BSE), we show that both phenomena exist thanks to reduced screening at short distances. This is not captured by common approximations used in ab initio BSE calculations, but requires vertex corrections that take the fermionic nature of charges into account. The electron-hole wavefunction of the low-energy modes shows strong and very anisotropic electron-hole correlation, which speaks for an excitonic character of these modes. The fact that short-range physics is at the origin of these phenomena explains why, on the other hand, also the simple adiabatic local density approximation to time-dependent density functional theory can capture these effects. (10.1103/PhysRevLett.134.046402)
  DOI : 10.1103/PhysRevLett.134.046402
• 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
• Type I and type II superconductivity in a quasi-2D Dirac metal
  
  • Lygouras Chris
  • Zhang Junyi
  • Gautreau Jonah
  • Pula Mathew
  • Sharma Sudarshan
  • Gao Shiyuan
  • Berry Tanya
  • Halloran Thomas
  • Orban Peter
  • Grissonnanche Gael
  • Chamorro Juan
  • Mikuri Taketora
  • Bhoi Dilip
  • Siegler Maxime
  • Livi Kenneth J.T.
  • Uwatoko Yoshiya
  • Nakatsuji Satoru
  • Ramshaw B.
  • Li Yi
  • Luke Graeme
  • Broholm Collin
  • Mcqueen Tyrel
  Materials Advances, Royal Society of Chemistry, 2025, 6 (5), pp.1685-1694. Dirac material LaCuSb 2 shows anisotropic superconducting response to applied magnetic fields. Abstract: We explore bulk superconducting phase in single crystals of the Dirac material LaCuSb2 prepared by the self-flux method. Magnetization, muon spin relaxation measurements, and density functional theory, show the Dirac nodal line Fermi surfaces give rise to type-II superconductivity for magnetic fields applied along the a-axis, and type-I superconductivity for fields along the c-axis. Both chemical and hydrostatic pressure drastically suppress the superconducting transition. We find multiband superconductivity evidenced by a precipitous drop in the electronic specific heat capacity and high-pressure susceptibility for T* < Tc/3. Our work demonstrates dirty-limit, weak-coupling multiband superconductivity in LaCuSb2, and highlights the role of Dirac fermions on its anisotropic character. (10.1039/D5MA00022J)
  DOI : 10.1039/D5MA00022J
• 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
• 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
• 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
• 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