Publications

2025

• Temperature and doping level effect on silicon thermal conductivity
  
  • Acosta Abanto Juan Carlos
  • Brouillard Mélanie
  • Sen Raja
  • Sjakste Jelena
  • Paulatto Lorenzo
  • Saint-Martin Jérôme
  • Vast Nathalie
  • Robillard J.F.
  • Horny Nicolas
  • Gomés Séverine
  • Chapuis Pierre-Olivier
  , 2025.
• Unraveling energy flow mechanisms in semiconductors by ultrafast spectroscopy: Germanium as a case study
  
  • Raciti Grazia
  • Abad Begoña
  • Dettori Riccardo
  • Sen Raja
  • Sivan Aswathi K
  • Sojo-Gordillo Jose M
  • Vast Nathalie
  • Rurali Riccardo
  • Melis Claudio
  • Sjakste Jelena
  • Zardo Ilaria
  , 2025. Semiconductor materials are the foundation of modern electronics, and their functionality is dictated by the interactions between fundamental excitations occurring on (sub-)picosecond timescales. Using time-resolved Raman spectroscopy and transient reflectivity measurements, we shed light on the ultrafast dynamics in germanium. We observe an increase in the optical phonon temperature in the first few picoseconds, driven by the energy transfer from photoexcited holes, and the subsequent decay into acoustic phonons through anharmonic coupling. Moreover, the temperature, Raman frequency, and linewidth of this phonon mode show strikingly different decay dynamics. This difference was ascribed to the local thermal strain generated by the ultrafast excitation. We also observe Brillouin oscillations, given by a strain pulse traveling through germanium, whose damping is correlated to the optical phonon mode. These findings, supported by density functional theory and molecular dynamics simulations, provide a better understanding of the energy dissipation mechanisms in semiconductors.
• Encoding magnetic anisotropies in digital light processing 3D printing
  
  • Aïdonidis Eléonore
  • Cosola Andrea
  • Bourdon Pierre
  • Dammak Hichem
  • Sangermano Marco
  • Demoly Frédéric
  • Faustini Marco
  • Pérot Amélie
  • Lairez Didier
  • Mouhoubi Rakine
  • Blanquer Sébastien
  • Rizza Giancarlo
  Advanced Functional Materials, Wiley, 2025, 2025, pp.e23995. Magnetic fields are increasingly used in 4D printing to program matter across multiple length scales, enabling control over both macroscopic structures and nanoscale particle organization. However, their integration into additive manufacturing remains limited by compatibility constraints—such as interference with extrusion or optical access—and the inherent challenge of generating spatially resolved, dynamic magnetic fields. In this work, a digital light processing 3D printing method is introduced that directly encodes programmable magnetic anisotropy during fabrication. By formulating a photocurable resin with magnetic nanoparticles and liquid crystal monomers, composite structures are fabricated that respond to both magnetic and thermal stimuli. A hybrid magnetic system—combining a nested Halbach array with a coaxial coil placed in its inner cavity—enables real‐time, 3D control of magnetic fields (in both direction and intensity) during the printing process. This approach enables the alignment of liquid crystal mesogens, magnetic fillers, and the formation of vertically oriented nanoparticle chains. The resulting materials exhibit direction‐dependent actuation, shape reconfiguration, and selective conductivity, demonstrating a versatile platform for creating multifunctional and multi‐stimuli‐responsive devices. (10.1002/adfm.202523995)
  DOI : 10.1002/adfm.202523995
• Arising of a bulk plasmon in the optical response of a WS 2 monolayer: an ab initio prediction confirmed experimentally
  
  • Andriambelaza Noeliarinala Felana
  • Sottile Francesco
  • Di Berardino Gaia
  • Noubiwo Laeticia
  • Chaste Julien
  • Oehler Fabrice
  • de Oliveira Nelson
  • Schué Léonard
  • Ouerghi Abdelkarim
  • Sirotti Fausto G
  • Giorgetti Christine
  , 2025. Ab initio formalisms allow state-of-the-art calculations to predict optical properties of materials. Time dependent density functional theory in reciprocal space is a robust and efficient framework for bulk crystalline materials, and it has been widely used to study the electronic excitations of isolated nano-objects. Several difficulties arise from the use of a supercell, coming both from the vacuum added to the object and from the interactions between artificial replicas. We recently proposed a framework to overcome both these problems, which predicts that the optical response of a two dimensional object is a linear combination of the absorption and the bulk plasmon resonances, namely the coexistence of a transverse and a longitudinal excitations. In this paper, we apply our formalism to monolayers of pristine WS2 and WSe2 and prove our theoretical findings by measuring the transmittance of these objects in the vacuum ultraviolet range for different incident angles of a polarized electromagnetic field.
• Tunable electronic band structure in WS 2(1-x) Se 2x van der Waals Alloys
  
  • Bouaziz Meryem
  • Schué Léonard
  • Andriambelaza Noeliarinala Felana
  • Alyabyeva Natalia
  • Girard J.-C.
  • Dudin Pavel
  • Cadiz Fabian
  • Avila José
  • Dappe Y. J.
  • González César
  • Chaste Julien
  • Oehler Fabrice
  • Giorgetti Christine
  • Sirotti Fausto G
  • Ouerghi Abdelkarim
  Physical Review B, American Physical Society, 2025. <div><p>The electronic structure of semiconducting 2D materials such as transition metal dichalcogenides (TMDs) is known to be tunable by its environment, from simple external fields applied with electrical contacts up to complex van der Waals heterostructure assemblies. However, conventional alloying from reference binary TMD compounds to composition-controlled ternary alloys also offers unexplored opportunities. In this work, we use nano-angle resolved photoemission spectroscopy (nano-ARPES) and density functional theory (DFT) calculations to study the structural and electronic properties of different alloy compositions of bulk WS 2(1-x)Se2x.</p><p>Our results demonstrate the continuous variation of the band structure and the progressive evolution of the valence band splitting at the K points from 420 to 520 meV in bulk WS2(1-x)Se2x. We also carried out scanning tunneling microscopy (STM) measurements and DFT to understand the possible S or Se substitutions variants in WS2(1-x)Se2x alloys, with different local atomic configurations. Our work opens up perspectives for the fine control of the band dispersion in van der Waals materials and demonstrate how the band structure can be tuned in bulk TMDs. The collected information can serve as a reference for future applications.</p></div>
• About carrier's self-trapping and dynamical Rashba splitting in the two-dimensional hybrid perovskite (BA)$_2$(MA)$_2$Pb$_3$I$_{10}$
  
  • Qi W.
  • Ponzoni S.
  • Huitric G.
  • Gorelov V.
  • Pramanik A.
  • Laplace Y.
  • Marsi M.
  • Papalazarou E.
  • Maehrlein S.
  • Deleporte E.
  • Mallik N.
  • Ibrahimi A. Taleb
  • Bendounan A.
  • Zheng K.
  • Pullerits T.
  • Perfetti L.
  , 2025. Time- and Angle-Resolved Photoelectron Spectroscopy (tr-ARPES) is employed to monitor photoexcited electrons in the two-dimensional hybrid perovskite (BA)$_2$(MA)$_2$Pb$_3$I$_{10}$. Photoelectron intensity maps are in good agreement with ab-initio calculations of the band structure. The effective mass is $-0.18 \pm 0.02 m_e$ and $0.12 \pm 0.02 m_e$ for holes and electrons, respectively. In the photoexcited state, spin-orbit splitting of the conduction band cannot be resolved. This sets the upper bound of photoinduced Rashba coupling to $α_C&lt;2.5$ eVÅ. The correlated electron-hole plasma evolves in Wannier excitons with Bohr radius of 2.5 nm, while no sign of self-trapping in small polarons is found within the investigated time window of up to 120 ps following photoexcitation. (10.48550/arXiv.2508.12129)
  DOI : 10.48550/arXiv.2508.12129
• Picosecond anisotropic phase separation governing photoinduced phase stability in submicron Ti3O5 crystals
  
  • Mandal Ritwika
  • Lorenc Maciej
  • Cammarata Marco
  • Levantino Matteo
  • Zerdane S.
  • Janod Etienne
  • Cario Laurent
  • Tokoro Hiroko
  • Ohkoshi Shin-Ichi
  • Trzop Elzbieta
  • Servol Marina
  • Huitric Guénolé
  • Cailleau Hervé
  • Ta-Phuoc Vinh
  • Banhart Florian
  • Enachescu Cristian
  • Stoleriu Laurentiu
  • Mariette Céline
  Communications Materials, Nature, 2025, 6 (1), pp.209. Recently developed ceramic material Ti3O5 exhibits fascinating application properties, from ultrafast switching between metallic and insulating phases to light-to-heat conversion and storage. While the states conferring such properties are not spatially homogeneous, the origin of phase separation and the link between the phase coexistence and dynamics, key for stability of such states, is still little known. In this work, we use time-resolved X-ray diffraction and numerical simulations to establish rules by which the dynamics of heat-driven transition in laser excited Ti3O5 crystallites occur in space and time. The studies are conducted on submicron Ti3O5 crystallites and span a broad timescale allowing separation of phase change regimes. Our results reveal the influence of nanoscopic morphology on the mechanism of macroscopic transformation triggered by laser excitation. (10.1038/s43246-025-00896-y)
  DOI : 10.1038/s43246-025-00896-y
• Femtosecond-laser-delamination cavities for resonant acousto-magneto-plasmonics
  
  • Varlamov Pavel
  • Barros Akira
  • Swaminathan Aditya
  • Marx Jan
  • Ostendorf Andreas
  • Semisalova Anna
  • Makarov Denys
  • Lomonosov Alexey
  • Vavassori Paolo
  • Laplace Yannis
  • Raynaud Michele
  • Temnov Vasily
  Physical Review Letters, American Physical Society, 2025, 135 (12), pp.126904. Femtosecond lasers are routinely used for inducing local modification, including nanostructuring, and ultrafast laser spectroscopy in solids. However, these studies are often being performed separately making the unveiling of exciting physical properties of laser-fabricated materials out of reach. Here, we present an all-optical platform combining the fabrication of nano to micrometer size single-shot “femtosecond-laserdelamination” membranes or cavities of ferromagnetic thin films and multilayers together with their quasi in situ characterization using the Abbe-limited interferometric, ultrafast scanning photo-acoustic and magneto-plasmonic microscopies. Ferromagnetic nickel and iron cavities display high-Q acoustic resonances providing access to long-lived ultrahigh frequency coherent phonon modes in the above 100 GHz frequency range. Cavities in cobalt-gold bilayers allow for magnetically controlled surface plasmon resonance experiments in the Otto configuration, which is otherwise very difficult to implement experimentally. Quantitative experimental characterization of functional magnetic cavities, supported by the numerical modeling of all experimental data, opens an avenue to design and fabricate tunable nanoscaled femtosecond-laser-delamination architectures in thin films and multilayers. (10.1103/99sl-xxb2)
  DOI : 10.1103/99sl-xxb2
• Structure and dynamics of Electronic states in layered quantum materials
  
  • Qi Weiyan
  , 2025. Layered materials possess unique band structures and physical properties that distinguish them from three-dimensional materials, attracting widespread research interest over the past decades. These distinctive features arise from the strong intralayer atomic bonding and relatively weak interlayer interactions. Therefore, tuning the atom types, intralayer structures, the interlayer interactions, or even stacking different types of materials can fundamentally change the macroscopic physical properties of the system. This thesis focuses on the electronic structure properties of two representative classes of layered materials: transition metal dichalcogenides (TMDs) and two-dimensional perovskites. Using angle-resolved photoemission spectroscopy (ARPES) and its time-resolved extension (tr-ARPES), in combination with electron diffraction, Raman spectroscopy, and transient reflectivity measurements, we systematically investigate complex electronic many body effects, chiral superlattice switching, and electron phonon coupling phenomena in these materials.
• High-pressure, high-temperature phase equilibria with superhard boron-rich compounds of B-C-N-O and B-C-b–Si systems by in situ X-ray diffraction and CALPHAD methodology
  
  • Courac Alexandre
  • Le Godec Yann
  • Sjakste Jelena
  • Vast Nathalie
  • Rapaud Olivier
  • Turkevich Vladimir
  ACS Applied Materials & Interfaces, Washington, D.C. : American Chemical Society, 2025, 17 (38), pp.53013-53039. Boron-rich compounds within the B-C-N-O and B-C-Si systems exhibit exceptional functional properties, making them highly attractive for industrial applications such as those requiring superhardness, nuclear technologies, or thermoelectricity. This review summarizes recent experimental and theoretical advances on high-pressure, high-temperature (HPHT) phase equilibria up to 20 GPa and 3000 K, focusing on boron carbide (B 4 C), boron suboxide (B 6 O), boron subnitride (B 13 N 2 ), boron silicides and some of their solid solutions. Emphasis is placed on in situ x-ray diffraction (XRD), density functional theory (DFT) calculations and CALPHAD thermodynamic modeling. Despite recent progress, significant methodological challenges remain, requiring enhanced experimental accuracy and refined theoretical approaches. Future work should address these gaps to fully leverage the potential of these superhard materials. (10.1021/acsami.5c08312)
  DOI : 10.1021/acsami.5c08312
• Online and in situ investigation of electron irradiation induced optical absorption in ZnGeP2 single crystals
  
  • Vernozy Charlotte
  • Alessi Antonino
  • Cavani Olivier
  • Courpron Audrey
  • Petit Johan
  • Véniard Valérie
  Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Elsevier, 2025, 566, pp.165758. In the present study, the absorbance induced in Zinc germanium diphosphide, ZnGeP 2 (ZGP) crystals and new Sn-doped ZGP crystals has been investigated under irradiation with high energy electrons. Online and in situ experiments were performed in the range 720-1100 nm. The spectra of the induced absorbance are constituted by a "tail" and the maximum appears to be located at wavelengths lower than those of the investigated spectral range. A fraction of the induced absorbance disappears within one minute after the electron beam is switched off, revealing the presence of metastable effects. A low and a high fluence contribution to the induced absorbance have been observed at 800 nm. The first reaches a limit value and seems to be affected by the Sn doping or by the absence of post-growth annealing, while the high fluence contribution does not feature a saturation in the investigated range and does not depend on the sample type. (10.1016/j.nimb.2025.165758)
  DOI : 10.1016/j.nimb.2025.165758
• Direct measurement of the longitudinal exciton dispersion in h -BN by resonant inelastic X-ray scattering
  
  • Nicolaou Alessandro
  • Ruotsalainen Kari
  • Susana Laura
  • Porée Victor
  • Tizei Luiz Galvao
  • Koskelo Jaakko
  • Taniguchi Takashi
  • Watanabe Kenji
  • Zobelli Alberto
  • Gatti Matteo
  Physical Review B, American Physical Society, 2025, 112 (8), pp.085207. We report resonant inelastic X-ray scattering (RIXS) measurements on the prototypical hexagonal boron nitride (h-BN) layered compound. The RIXS results at the B and N K edges have been combined with electron energy loss spectroscopy (EELS) experiments and ab initio calculations within the framework of the Bethe-Salpeter equation of many-body perturbation theory. By means of this tight interplay of different spectroscopies, the lowest longitudinal exciton of h-BN has been identified. Moreover, its qualitatively different dispersions along the ΓK and the ΓM directions of the Brillouin zone have been determined. Our study advocates soft x-ray RIXS and EELS to be a promising combination to investigate electronic excitations in materials. (10.1103/wn39-b2sh)
  DOI : 10.1103/wn39-b2sh
• Anomalous frequency scaling of acoustic phonon damping in freestanding nickel cavities fabricated via laser delamination
  
  • Viejo Rodríguez Alba
  • Rossetti Andrea
  • Gandolfi Marco
  • Urbina Elgueta Yoav
  • Modin Evgeny
  • Starikovskaia Svetlana
  • Chng Tat Loon
  • Temnov Vasily
  • Vincenti Maria Antonietta
  • Brida Daniele
  • Vavassori Paolo
  • Maccaferri Nicolò
  Applied Physics Letters, American Institute of Physics, 2025, 127 (7), pp.072201. Single-shot picosecond (ps) laser-induced delamination allows for the direct generation of suspended membranes from a continuous metallic film, offering a promising platform for the control of ultrafast magnetization dynamics driven by acoustic waves. Using the picosecond-ultrasonics method, we demonstrate that long-lived low-frequency acoustic waves can be optically excited in the delaminated cavities. At the same time, higher-frequency modes above 60 GHz exhibit a surprisingly fast damping, following a scaling law incompatible with the expected attenuation mediated by phonon–phonon scattering. Comparing measurements between delaminated cavities and a benchmark nickel film in contact with the substrate, we link our findings to structural modifications of the nickel crystal induced by the delamination process. (10.1063/5.0263631)
  DOI : 10.1063/5.0263631
• Dose Rate Effects in Ag-Doped Metaphosphate Glass Radiophotoluminescent Dosimeters Up to MGy Range
  
  • Aguiar Y.
  • Alía R. García
  • Kranjčević M.
  • Cecchetto M.
  • Söderström D.
  • Mandal A. Raj
  • Gascon J.
  • Trummer J.
  • Vincke H.
  • Alessi A.
  • Cavani O.
  • Constantino A.
  • Lerner G.
  • Sostero L.
  • Girard S.
  • Ferrari M.
  IEEE Transactions on Nuclear Science, Institute of Electrical and Electronics Engineers, 2025, 72 (8), pp.2570-2577. This work presents a comprehensive study of dose rate effects on Ag-doped metaphosphate glass radiophotoluminescence (RPL) dosimeters for doses ranging between 1 Gy and 100 MGy. Data from multiple irradiation campaigns with diverse radiation fields, such as 60Co gamma radiation, X-rays with energy spectrum up to 100 keV, monoenergetic electron beams, and mixed fields offer valuable insights for accurate dosimetry in high-radiation environments. Dose rates ranging over eight decades, from 0.1 kGy/h to 18 MGy/h, are experimentally tested. Low dose rate effects can be observed at low doses; however, for doses higher than 100 kGy, both overestimation and underestimation can occur depending on the dose rate. (10.1109/TNS.2025.3549949)
  DOI : 10.1109/TNS.2025.3549949
• Design principles for density functionals using a linear expansion
  
  • Aouina Ayoub
  • Gatti Matteo
  • Reining Lucia
  npj Computational Materials, Springer Nature, 2025, 11, pp.242. Density Functional Theory is one of the most widely used theoretical approaches for the calculation of properties of materials, but the systematic development of new functionals with controllable accuracy is an ongoing challenge. We propose to use perturbation theory around the homogeneous electron gas in a way that is optimized using physical insight, and to combine it with the recently developed connector approach in order to satisfy an exact limit. In this way, we develop an explicit non-local density functional for the Kohn-Sham exchange correlation potential. First results for the self-consistently calculated charge density and potential for three prototype materials demonstrate which accuracy can be reached for the charge density, confirm the systematicity of the approach, and suggest directions for further improvement. (10.1038/s41524-025-01712-4)
  DOI : 10.1038/s41524-025-01712-4
• Reactivity of Constitution vs. Crystallization Water Under Irradiation: Insights from Tobermorites
  
  • Herin Thibaut
  • Alessi Antonino
  • Charpentier Thibault
  • Poyet Stéphane
  • Bouniol Pascal
  • Le Caër Sophie
  International Journal of Hydrogen Energy, Elsevier, 2025, 149, pp.150042. Understanding radiolytic H₂ production in irradiated cement is crucial for nuclear waste safety, yet the role of solid cement phases remains unclear. This study examines the behavior of model minerals -tobermorite 11 Å (Ca₅Si₆O₁₇.5H₂O) and tobermorite 9 Å (Ca₅Si₆O₁₆(OH)₂)-under electron irradiation. When fully dried, these minerals retain only crystallization water or structural hydroxyl groups, respectively. The results reveal that while crystallization water decomposes under irradiation, it does not lead to H₂ formation, as hydrogen atoms react with radiation-induced defects to form SiO-H bonds. In contrast, tobermorite 9 Å produces H₂ only when surface SiO-H bonds are present, indicating that radiolytic dihydrogen arises from surface bond breakage, while the cleavage of the bonds in the material does not ultimately lead to H₂ production. These findings enhance our understanding of irradiation effects on cementitious materials, aiding in the assessment of their long-term stability in nuclear waste storage. (10.1016/j.ijhydene.2025.150042)
  DOI : 10.1016/j.ijhydene.2025.150042
• 1D nanoporous membrane boosts the ionic conductivity of electrolytes.
  
  • Berrod Quentin
  • Zanotti J.-M.
  • Judeinstein Patrick
  • Pinchart Camille
  • Modesto Nino
  • Gigmes Didier
  • Phan T. N. Trang
  • Lairez Didier
  • Ramos Raphael
  • Coasne Benoit
  , 2025.
• Unconventional solitonic high-temperature superfluorescence from perovskites
  
  • Biliroglu Melike
  • Türe Mustafa
  • Ghita Antonia
  • Kotyrov Myratgeldi
  • Qin Xixi
  • Seyitliyev Dovletgeldi
  • Phonthiptokun Natchanun
  • Abdelsamei Malek
  • Chai Jingshan
  • Su Rui
  • Herath Uthpala
  • Swan Anna
  • Temnov Vasily
  • Blum Volker
  • So Franky
  • Gundogdu Kenan
  Nature, Nature Publishing Group, 2025, 642 (8066), pp.71-77. Fast thermal dephasing limits macroscopic quantum phenomena to cryogenic conditions1,2,3,4 and hinders their use at ambient temperatures5,6. For electronic excitations in condensed media, dephasing is mediated by thermal lattice motion1,7,8. Therefore, taming the lattice influence is essential for creating collective electronic quantum states at high temperatures. Although there are occasional reports of high-Tc quantum effects across different platforms, it is unclear which lattice characteristics and electron–lattice interactions lead to macroscopically coherent electronic states in solids9. Here we studied intensity fluctuations in the macroscopic polarization during the emergence of superfluorescence in a lead halide perovskite10 and showed that spontaneously synchronized polaronic lattice oscillations accompany collective electronic dipole emission. We further developed an effective field model and theoretically confirmed that exciton–lattice interactions lead to a new electronically and structurally entangled coherent extended solitonic state beyond a critical polaron density. The analysis shows a phase transition with two processes happening in tandem: incoherent disordered polaronic lattice deformations establish an order, while macroscopic quantum coherence among excitons simultaneously emerges. Recombination of excitons in this state culminates in superfluorescence at high temperatures. Our study establishes fundamental connections between the transient superfluorescence process observed after the impulsive excitation of perovskites and general equilibrium phase transitions achieved by thermal cooling. By identifying various electron–lattice interactions in the perovskite structure and their respective role in creating collectively coherent electronic effects in solids, our work provides unprecedented insight into the design and development of new materials that exhibit high-temperature macroscopic quantum phenomena. (10.1038/s41586-025-09030-x)
  DOI : 10.1038/s41586-025-09030-x
• Enhanced Electromagnetic Wave Absorption in Mapbi₃ Hybrid Perovskite Through a Defect‐Tunable Green Synthesis
  
  • Cai Yihui
  • Bégin Dominique
  • Lefevre Christophe
  • Sidhoum Charles
  • Elkaïm Erik
  • Boulet Pascal
  • Desgardin Pierre
  • Barthe Marie-France
  • Helm Ricardo
  • Egger Werner
  • Butterling Maik
  • Wagner Andreas
  • Papaefthimiou Vasiliki
  • Zafeiratos Spiros
  • Cianferani Damien
  • Mager Loic
  • Ersen Ovidiu
  • Corbel Catherine
  • Sanchez Clément
  • Bégin-Colin Sylvie
  Small Structures, Wiley, 2025, 6 (9), pp.2500066. Defect engineering and structure‐property relationship understanding in methylammonium lead iodide (MAPI) hybrid perovskites (HPs) attract significant scientific interest, as synthesis‐related defects may strongly influence intrinsic properties. We have explored a green solvent‐free synthesis—mechanosynthesis—leading to large quantities of MAPI powder with tuneable defect density suitable to study MAPI as an electromagnetic wave absorbing (EMWA) material. A dielectric loss enhancement was revealed at 11.4 GHz (X‐band) for 4 h‐ground MAPI powders (MAPI4h), compared to 30 min‐ground powders (MAPI30) when the particle size was &lt;20 μm. MAPI powders display a fractal microstructure with agglomerates of clusters of (nano)grains (≈80 nm for MAPI4h), consisting further of oriented smaller nanograin (5–10 nm) clusters. A strong reabsorption in smaller particles was evidenced due to a surface‐defective layer. MAPI4h was shown to display a more surface‐defective layer with a higher defect density gradient from surface to (nano)grains core and unique open defects different from those in solution‐processed MAPI. These vacancy‐type surface defects would enhance dipole polarization by stabilizing methylammonium dipoles, thereby increasing permittivity. The improved dispersion of MAPI particles (&lt;20 μm) in polymeric matrixes enhanced the surface effects and effective interactions with electromagnetic waves. This study demonstrated the potential of this green synthesis for producing large amount of HPs and tuning defects, opening new avenues for HPs EMWA application. (10.1002/sstr.202500066)
  DOI : 10.1002/sstr.202500066
• How exotic oxide glasses can provide solutions for integrated optics ?
  
  • Cardinal Thierry
  • Alassani Fouad
  • Zaiter Rayan
  • Fargues Alexandre
  • Jubera Veronique
  • Ollier Nadège
  • Lancry Matthieu
  • Vallée Réal
  • Petit Yannick
  • Canioni Lionel
  , 2025.
• Phonon dynamics investigation of phase transitions: the case of CDW 1T-TaS2
  
  • Péronne Emmanuel
  • Lample Pierrick
  • Weis Mateusz
  • Cario Laurent
  • Perfetti Luca
  • Boschetto Davide
  , 2025. The layered dichalcogenide 1T-TaS2 crystal represents a paradigm in the study of quantum materials, particularly in the context of charge density wave (CDW) phenomena1,2. Renowned for its series of CDW transitions, including incommensurate (IC), nearly commensurate (NC), and commensurate (C) phases, 1T-TaS2 exhibits a rich landscape of electron-lattice interactions and phase behaviors3,4. In the C-phase, typically below 174 K, the Ta atoms arrange a regular pattern, forming David's star configuration, which is repeated periodically to cover the entire crystal, creating a super-lattice5,6. Above 215 K, the TaS2 lattice reaches the NC phase where some of the David stars disappear, breaking, at long range, the super-lattice properties. While some regions keep David's star super-lattice structure, other regions loose the super-lattice character which leads to a lattice incommensurability. Such changes in the TaS2 induce a shrinkage of the band gap at the Fermi surface leading to more metallic behavior. Here, we use coherent phonon spectroscopy to investigate two coherent phonon modes in the 1T-TaS2 bulk crystal at 2.05 and 2.30THz, respectively, as a function of the temperature across the phase transition along the hysteresis loop and as a function of the pump fluence. In particular, we observed that the amplitude of the two coherent phonon modes undergoes a hysteresis loops at the same temperature of the electrical resistivity when warming up and cooling down the crystal. We also observed that the low frequency mode is blue-shifted after several picoseconds for high pump fluence, a time scale which can be attributed to the photo-induced phase transition into the so called hidden phase or H-phase7,8. Both comparisons, between the phonons and the resistivity behavior and between the frequency jump and H phase prediction, give insight into the role of lattice vibrations and electron-phonon coupling during this phase transition.
• 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
• 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