Materials Science
Functionalization-Driven Charge Redistribution Enabling Ultra-High-Capacity V2B MBene Anode for Li/Na ion batteries: A First-Principles study
Shaiokh Bin Abi and Ahmed Zubair
Amid increasing global demand for clean, sustainable energy, the search for novel electrode materials has emerged as a crucial link to advancing future energy storage technologies. Here, we explored the potential of N-functionalized 2D MBene V2BN2 as anode materials for Li- and Na-ion batteries using first-principles calculations.
Phonon dispersion and ab initio molecular dynamics calculations were employed to assess the dynamic and thermal stability of the material. The intrinsic metallic properties of V2BN2 were revealed through electronic band structures and density of states analyses. Importantly, Bader charge analysis demonstrates substantial charge redistribution upon Li/Na adsorption, leading to stronger ion-substrate interactions compared to the pristine counterpart. This redistribution plays a decisive role in enhancing Li/Na ion adsorption and stabilizing ion accommodation. Furthermore, owing to favorable multilayer adsorption of Li and Na ions, V2BN2 exhibited high theoretical specific capacities of 1524 and 762 mAh/g, as well as low open
circuit voltages of 0.73 and 0.23 V for Li and Na, respectively. In addition, the energy barriers were calculated to be 0.49 and 0.29 eV for Li- and Na-ion transport, respectively, indicating rapid ion transport and excellent rate capability. These results indicate that V2BN2 holds significant potential as an anode material for next-generation rechargeable ion batteries.
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Materials Science · Cross-listed from cs.AI
Mined from Scientific Literature: Process Schemas for Atomic Layer Deposition and Etching in Materials Science
Sameer Sadruddin, Eleni Poupaki, Alex Watkins et al. (+5 more)
Atomic layer deposition (ALD) and atomic layer etching (ALE) are reported heterogeneously across experimental and simulation literature in materials science, hindering comparison and machine-actionable reuse. We present four domain-expert-reviewed JSON Schemas for ALD and ALE experimental and simulation processes. Curated with schema-miner and grounded in QUDT using schema-miner pro, the schemas structure materials, process conditions, configurations , and measured or predicted results. We compare their scope, structure, and semantic grounding, and demonstrate their use for schema-guided literature extraction and publication of structured records through ORKG templates.
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All authors Sameer Sadruddin, Eleni Poupaki, Alex Watkins, Bora Karasulu, Adriaan J. M. Mackus, Erwin Kessels, Sören Auer, Jennifer D'Souza
Materials Science
Unusual phase coexistence regime across the ferroelectric - paraelectric transition
M. Kopecký, J. Kub, E. de Prado et al. (+1 more)
A PbTiO3 epitaxial thin film grown on a DyScO3 substrate was studied by x-ray diffraction in the temperature range of 20-500 degrees Celsius. It is found that the ferroelectric to paraelectric phase transition proceeds through a peculiar transitional coexistence state extending between 402 degrees Celsius and 414 degrees Celsius. Within this temperature interval, at a temperature of 405 degrees Celsius, a domain structure transition occurs, at which the three-domain c/a1/a2 polytwin phase transforms into an ordinary c/a2 twinned phase. It is proposed that the coexistence of two independent twinned phases with the paraelectric phase is enabled by vertical strain gradients in the film.
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All authors M. Kopecký, J. Kub, E. de Prado, J. Hlinka
Materials Science · Cross-listed from cond-mat.mes-hall
Catastrophes, Optical Multistabilities, and Chiral Photocurrent Hysteresis in Driven Weyl Semimetals
Christopher Yang, Gil Refael and Frederik Nathan
The unique band
topology of Weyl semimetals provides them with a diverse array of strong photovoltaic response phenomena. Here we explore how
plasma screening affects these phenomena. We find that the screening field is highly nonlinear, can contain topological contributions, and can amplify the photoresponse, with the self-consistent response exhibiting the hallmarks of bistability, including hysteresis and catastrophes. The bistability emerges from a crossover from linear to saturated polarization as a function of the field amplitude, because carriers in a Weyl cone have bounded group speed $v_F$. When time-reversal
symmetry is broken, tilted Weyl nodes add a Berry-
curvature contribution to the in-plane current, making the nonlinear screening response helicity selective.
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Materials Science · Cross-listed from cond-mat.str-el
Effective Ionic Valence and Local Magnetic Moment in Kagome Superconductors
Ruoshi Jiang, Zi-Jian Lang, Yuzki Oey et al. (+11 more)
In order to understand the unexpected similarity and the correlated behavior in kagome
superconductor families AV$_3$Sb$_5$ (A = K, Rb, Cs) and ATi$_3$Bi$_5$ (A = Rb, Cs), we investigate the Hartree-scale local electronic structure of these systems. Our result indicates that V and Ti ions are both of 2+ valence such that the corresponding itinerant carrier densities are similar, and the difference in electron count is instead reflected in their
quantum fluctuating ionic
magnetic moments. However, due to the frustrated
lattice geometry of these materials, such local moments are difficult to experimentally observe via standard probes. For verification, we systematically introduce nonmagnetic Sn impurities to locally relieve the
geometric frustration and experimentally demonstrate the existence of well-defined local
magnetic moments via
magnetic susceptibility and
muon spin rotation or relaxation ($\mu$SR) measurements. All experiments discover a systematic increase of
magnetic susceptibility upon increasing nonmagnetic impurity level. Our discovered ionic moments suggest a paradigm shift from the existing itinerant carrier-only picture to one incorporating strong correlation from local ionic
spins. The associated interatomic and local-itinerant correlations offer a solid ground for the emergence of the observed rich correlated behavior in this new family of superconducting materials.
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All authors Ruoshi Jiang, Zi-Jian Lang, Yuzki Oey, Andrea Capa Salinas, Stephen D. Wilson, Yongwei Li, Ilya Shipulin, Yiwen Zhang, Deng Hu, Zhiwei Wang, Hans-Henning Klauss, Zurab Guguchia, Vadim Grinenko, Wei Ku
Materials Science · Cross-listed from cond-mat.str-el
Low temperature thermodynamics of $S_{\mathrm{eff}}=1/2$ triangular lattice quantum spin liquid candidate TlYbS$_2$
Bishnu P. Belbase, Arjun Unnikrishnan, Piyush Chhallare et al. (+8 more)
Geometrically frustrated triangular-
lattice antiferromagnets exhibit a delicate competition between
magnetic order and
quantum spin liquid (QSL) behavior, with the Yb-based delafossite family $A$Yb$X_2$ providing a structurally clean platform for exploring this physics. Here, we report a comprehensive study of single-
crystal TlYbS$_2$ using DC magnetization, AC susceptibility, electron
spin resonance (ESR), and specific heat measurements extending from room temperature to the millikelvin regime. Single-
crystal X-ray diffraction confirms a trigonal $R\bar{3}m$ structure comprising well-separated triangular layers of Yb$^{3+}$ ions with no detectable site disorder. At zero field, a weak thermodynamic anomaly is observed near $530$ mK, which may indicate the onset of a weakly ordered state similar to that reported in KYbSe$_2$. Below $300$ mK, the zero-field
magnetic specific heat follows $C_{\rm m}\propto T^{1.8}$, close to a quadratic temperature dependence, in contrast to the linear temperature dependence reported for the sister compound TlYbSe$_2$, which has been described in terms of the interplay between spinons and thermally excited gauge-flux excitations. Magnetization and ESR measurements establish pronounced easy-plane
magnetic anisotropy, with $g_\perp/g_\parallel \approx 6.9$. The anomaly near $530$ mK exhibits a strongly anisotropic response to
magnetic field. For $H\perp c$, it remains visible up to approximately $2$ T and continuously evolves toward a field-induced ordered phase above approximately $2.5$ T, followed by a sequence of field-induced phases that includes a $1/3$ magnetization plateau between approximately $5$ and $8$ T and full polarization near $17$ T. In contrast, for $H\parallel c$, the anomaly weakens and is suppressed near $3$ T, consistent with the recently reported confinement–deconfinement transition from an ordered state to a field-induced QSL.
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All authors Bishnu P. Belbase, Arjun Unnikrishnan, Piyush Chhallare, Mohan B. Neupane, Eun Sang Choi, Sebastian Erdmann, Muhammad U. Akbar, Mamoun Hemmida, H.-A. Krug von Nidda, Philipp Gegenwart, Arnab Banerjee
Materials Science
Sparse data limit what a mechanistic corrosion model can predict
Conrard Giresse Tetsassi Feugmo
Mechanistic corrosion models are routinely fitted with four to six parameters to a few measurements and extrapolated across service lifetimes, yet whether the data determine them is rarely tested. We identify a reduced point defect model for the duplex oxide on Nb-stabilized AISI 347 in simulated boiling-water-reactor water from published depth profiles at three exposure times, by differentiable inversion graded against a closed-form reference. Profile likelihood, a 1000-member bootstrap and a prior-relaxation test agree that one of the five parameters is undetermined and a second only weakly so, and that 95% of the fit statistic rests on three chromium points. The kinetics track an empirical power law over the calibration window but diverge from it by a factor of 3.5 to 6.3 at ten years, outside the propagated uncertainty band. That separation, not the thickness it brackets, is what these data determine; an exposure near 3000 hours would resolve it.
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Materials Science
High-Temperature ferromagnetism from site-selective filling in (Fe,Ni)$_{6-\delta}$GeTe$_2$
Tyler L. Werner, Jonathan T. Reichanadter, Xiang Chen et al. (+23 more)
The discovery of high-temperature ferromagnetism in the metallic van der Waals (vdW) system Fe$_N$GeTe$_2$ has brought two-dimensional (2D) magnets into technologically relevant temperature scales. Specifically at N = 5, dilution of
magnetic moments by nickel substitution counterintuitively achieves a record high Curie temperature of 478~K. Unraveling the origin of this nickel-substitution-induced enhancement is complicated by the compound's structural complexity, coexistent itinerant and local
magnetic contributions, and mesoscopic compositional domains. Through coordinated structural and electronic characterization, we identify that the high-T$_C$
magnetic phase arises from a strain-stabilized Fe$_6$GeTe$_2$ nano-precipitate. Combining first-principles calculations and
spin- and angle-resolved photoemission spectroscopy (ARPES), we uncover a site-specific electronic landscape in which interior iron atoms primarily host localized moments while the outer iron atoms neighboring the tellurium layers produce
spin-polarized itinerant carriers that cross the vdW gap. The large energy cost associated with homogeneous nickel substitution is found to favor the spontaneous precipitation of the crystallographically and electronically “clean” high-T$_C$ phase. Finally, we compare metal-rich vdW magnets with binary
magnetic alloys, and discuss the unifying roles of nano-precipitates in stabilizing otherwise unattainable bulk phases. Our work provides mechanistic insights into the record-high T$_C$ ferromagnetism in (Fe,Ni)$_{5+\delta}$GeTe$_2$, establishing a rigorous foundation for the atomic engineering of vdW
magnetic metals informed by direct electronic signatures.
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All authors Tyler L. Werner, Jonathan T. Reichanadter, Xiang Chen, Pranab K. Nag, Luna Y. Liu, Yu-Tsun Shao, Hongrui Zhang, Mingyang Guo, Wenxin Li, Zhibo Kang, Han Wu, Makoto Hashimoto, Donghui Lu, Turgut Yilmaz, Elio Vescovo, Sung-Kwan Mo, Barat Achinuq, Alexei Fedorov, Jacob C. Ruff, Ming Yi, Qiong Ma, David A. Muller, Eduardo H. da Silva Neto, Robert J. Birgeneau, Jeffrey B. Neaton, Yu He
Materials Science
High-fidelity k$\cdot$p representations of first-principles electronic band structures through covariant renormalization
Kristian Berland
The k$\cdot$p method can be applied directly to first-principles energies and momentum
matrix elements, but the resulting models converge slowly with the number of bands and are inexact wherever the underlying
Hamiltonian is nonlocal. We show that both limitations can be largely removed by renormalizing the
eigenvalue spectra of the Hermitian momentum
matrices. These spectra are gauge invariant, and are identical along
symmetry-related directions; hence scaling the recurring magnitudes provides a modest set of parameters that preserves degeneracies and
crystal symmetry without needing to construct a
symmetry-adapted basis. We choose to renormalize the models against reference
eigenvalues and band velocities on rays out of a high-
symmetry point. For GaP, a 15-band model can reproduce the band structure in the near-gap reference regions within a few meV. For zincblende and wurtzite AlN, similar accuracy requires 30- or 85-band models, which in the case of zincblende is traced to the strong warping in the [110] direction. The scheme readily generalizes to rocksalt PbTe, which includes
spin-orbit coupling, and has $L$-centered valence- and conduction-band extrema. Further, we demonstrate, for GaP, how compact four-band
Hamiltonians can be obtained by downfolding within the same renormalization scheme. Moreover, by changing the fitting regime to encompass the entire Brillouin zone, the scheme can be used to generate full-zone models that reproduce the density of states. A practical use of the method is illustrated with a 59-band k$\cdot$p model for GaP, which can be evaluated on meshes far denser than the reference calculation, that in turn can be used both to resolve fine features in the density of states and to compute the hole conductivity at low temperature.
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Materials Science
Piezomagnetism in a model cubic noncollinear altermagnet
Sudarshan Sharma, Luca Buiarelli, Richard Spieker et al. (+4 more)
Altermagnets constitute a distinct class of
magnetic materials that combine compensated
magnetic order with
spin-polarized electronic bands, hence carrying characteristics of both antiferromagnets and ferromagnets. Piezomagnetism - the linear relationship between
lattice strain and a net
magnetic moment - has emerged as smoking-gun evidence of altermagnetism that distinguishes it from antiferromagnetism. Here, we uncover a large piezomagnetic response in MnTe2, a cubic altermagnet with a noncollinear
spin arrangement and weak
spin-orbit coupling. We combine dilatometry with nuclear
magnetic resonance, a bulk local probe, to observe signatures of both direct and inverse piezomagnetism consistent with
symmetry considerations and first-principles calculations. The dilatometry measurements reveal a shear deformation proportional to an applied
magnetic field, while
magnetic resonance detects a ferromagnetic moment induced by shear strain. The respective results for the piezomagnetic coupling strength are in good agreement, and they are captured by first-principles results. These findings for simple binary MnTe2 position this material as a model altermagnet, demonstrate the utility of nuclear
magnetic resonance in investigations of piezomagnetism, and open new avenues for
multimodal strain and
magnetic-field control in spintronic and
memory applications.
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All authors Sudarshan Sharma, Luca Buiarelli, Richard Spieker, Ivan Jakovac, Damjan Pelc, Turan Birol, Martin Greven
Materials Science
Device Engineering and Performance Optimization of Cu2NiGeS4 Thin-Film Solar Cells with In2S3/MoTe2 Charge-Selective Layers: A Computational Study
Md Tashfiq Bin Kashem and Hasib Md Abid Bin Farid
The pursuit of efficient and sustainable thin-film photovoltaics increasingly demands absorber materials that combine strong optical absorption with earth-abundant and environmentally benign constituents. Cu2NiGeS4 (CNGS) has emerged as a promising quaternary chalcogenide absorber owing to its favorable optoelectronic properties and high absorption coefficient, yet its photovoltaic potential remains comparatively underexplored, particularly in conjunction with optimized charge-selective layers. Here, we introduce and comprehensively investigate an CNGS-based solar-
cell architecture using SCAPS-1D, with In2S3 and MoTe2 serving as the electron and hole-transport layers respectively. The analysis of energy-band profiles, electric fields, carrier distributions, and generation-recombination characteristics reveals the mechanisms governing carrier separation and extraction across the heterojunctions. Systematic optimization of layer thickness, doping density, bulk and interface defect densities, recombination coefficients, parasitic resistances, temperature, and illumination intensity identifies the key factors limiting device performance. The optimized device is predicted to achieve a power conversion efficiency (PCE) of 28.44% with a open-
circuit voltage (VOC) of 0.984 V, short-
circuit current density (JSC) of 34.39 mA/cm2, and fill factor (FF) of 84.04%, under AM1.5G illumination at 300 K. This simulated efficiency exceeds the previously reported 6.25-21.17% range for CNGS-based solar
cells considered in this study. The findings establish In2S3/CNGS/MoTe2 as a promising platform for next-generation thin-film photovoltaics and provide physically grounded design guidelines for absorber optimization, interface engineering, and future experimental realization.
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Materials Science
Competition between vacancy creation and filling in defect-engineering of hBN
Shrirang Chokappa, Manuel Längle, Barbara Maria Mayer et al. (+13 more)
Hexagonal boron nitride (hBN) has recently become the focus of intense research as a material that can host
quantum emitters. It is known that such emission is related to point defects, but in order to conclusively correlate specific defects to their spectra, having control over the defect creation mechanism is required. Here, we prepare freestanding, monolayer hBN samples and irradiate them with ultra-low-energy (150 eV) Ar+ ions. The samples are characterized before and after irradiation via scanning transmission electron microscopy to assess the defect density and distribution. Contrary to what analytical potential molecular dynamics simulations have predicted, we predominantly observe boron single vacancies after ion irradiation, followed by double vacancies at half the count. Moreover, we also observe that vacancy filling with Si and C impurity atoms plays a more significant role in the created defects than previously assumed, potentially posing a problem for selective creation of
quantum emitters in hBN.
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All authors Shrirang Chokappa, Manuel Längle, Barbara Maria Mayer, Vladimir Zobač, Jacob Madsen, Diana Propst, David Lamprecht, Philipp Irschik, Arixin Bo, Clara Kofler, Vinzent Hana, Fabian Kraft, Clemens Mangler, Lado Filipovic, Toma Susi, Jani Kotakoski
Materials Science
High-throughput thermodynamic screening of oxide-scale adhesion across the CoCrFeMnNiAl high-entropy alloys
Dennis Boakye and Chuang Deng
One significant benefit of reactive element (RE) additions is the colossal improvement in oxide-scale retention during high-temperature oxidation. Selecting optimal RE dopants in high-
entropy alloys remains empirical because the relevant thermodynamic landscape is inaccessible to first-principles at the required compositional resolution. Here we apply the macroscopic atom model, coupled with McLean isotherm and Guttmann models, to screen adhesion across nine CoCrFeMnNiAl sub-families at \ce{Cr2O3} and \ce{Al2O3} interfaces, ranking five REs (Hf, Y, Zr, La, Ti) for segregation, adhesion enhancement, and sulfur displacement. The screening reveals an oxide-dependent ranking inversion, with Hf dominating at \ce{Cr2O3} and La dominating at \ce{Al2O3}, driven by the interplay between RE–O and RE–
matrix interaction enthalpies. Mn-containing
alloys exhibit intrinsic sulfur resistance, consistent with their experimentally observed oxidation characteristics. A sulfur immunity phase diagram identifies compositions with Al~+~Mn~$\gtrsim$~25~at% as thermodynamically immune to S-induced adhesion loss. All crossover concentrations collapse onto a universal exponential governed by the segregation enthalpy difference, providing a transferable design rule. Inverse design identifies \ce{Co16Cr16Fe16Ni16Al35} as the optimal S-immune composition with $W_\text{sep} = 5.95$~J/m$^2$ without RE doping.
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Materials Science · Cross-listed from physics.chem-ph
Breaking Water at Graphene Defects
Samuel G. H. Brookes, IniOluwa C. Popoola, Fabian Berger et al. (+3 more)
Water dissociation at solid surfaces underpins processes ranging from corrosion and catalysis to electrochemistry and photovoltaics. Defects often serve as reactive sites for dissociation, yet how solvation influences water dissociation at such sites remains poorly understood. Here, we use state-of-the-art machine-learned interatomic potentials to explore water dissociation at defective
graphene-water interfaces. We show that solvation qualitatively changes the reaction mechanism at a
graphene single vacancy (SV), opening pathways that are absent for an isolated water molecule. Whereas the gas-phase process proceeds via a single concerted channel, the solvated SV splits water through two competing pathways: a basic route forming SV-H and OH-(aq), and an acidic route forming SV-OH and H3O+(aq). These lower-barrier pathways produce distinct chemisorbed intermediates that enhance
graphene-water adsorption. Accordingly, even a simple carbon vacancy gives rise to unexpectedly rich interfacial chemistry, coupling surface chemistry to interfacial charge and wettability, with implications for carbon functionalization and nanofluidic transport.
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All authors Samuel G. H. Brookes, IniOluwa C. Popoola, Fabian Berger, Kara D. Fong, Angelos Michaelides, Christoph Schran
Materials Science
Effect of Stress and Surface Roughness on Electrodeposition in All-Solid-State Batteries: A Computational Investigation
Kaniza Islam, Ayush Morchhale, Jung-Hyun Kim et al. (+2 more)
All-solid-state batteries (ASSBs) promise high energy density and enhanced safety, but their development is hindered by instability and incompatibility at solid-solid interfaces. In Li-metal ASSBs, lithium penetration occurs despite stiff ceramic electrolytes via grain boundaries, often initiated by minor Li/SE interfacial irregularities. Here we introduce a two-dimensional continuum model with electro-chemo-mechanical coupling to investigate interfacial current distribution in Li ASSBs with surface-roughened argyrodite electrolyte under stack pressures and applied current density. Our theoretical analysis and simulation studies highlight the critical role of mechanical stress in interfacial current distribution. We find that prominent stress variations around elongated surface protrusions are the key to nonuniform Li deposition, without which Li deposition becomes uniform even on a rough surface. Moreover, our parametric study elucidates that stress effects dominate the overpotential and current distribution under low interfacial current density to exchange current density ratios, otherwise the high interfacial resistance due to surface-roughness-induced interfacial area becomes dominant. With these insights, we also discuss the potential of engineering artificial interlayers to modulate interfacial current distributions, offering guidance for improving the long-term performance and reliability of ASSBs.
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All authors Kaniza Islam, Ayush Morchhale, Jung-Hyun Kim, Yanzhou Ji, Noriko Katsube
Materials Science
Skyrmion nucleus resolves the Landauer paradox
Jiyuan Yang, Denan Li and Shi Liu
Ferroelectric switching is among the most fundamental and widely studied
symmetry-breaking processes in physics. However, the Landauer paradox asserts that an ideal single-domain ferroelectric should be kinetically unswitchable, because a three-dimensional reversed
nucleus would carry a prohibitive depolarization penalty, leading to unphysically large coercive field (the electric field required to switch the polarization). Here we show that this long-standing paradox is resolved by
topology. In defect-free PbTiO3, large-scale molecular dynamics simulations reveal that the intrinsic critical
nucleus is a three-dimensional polar skyrmion. Its continuous polarization rotation and Néel-type boundary walls self-compensate bound charge, suppressing the depolarization energy by orders of magnitude and bringing the predicted coercive field into agreement with experiment. This topological
nucleus further overturns the 60-year-old Janovec-Kay-Dunn law. We derive an analytical thickness-dependent coercive-field law governed by field-induced softening of the parent ferroelectric state and controlled by a single material descriptor. This framework captures diverse experimental trends across ferroelectric families and recasts the Kay-Dunn exponent of -2/3 as an effective finite-window behavior. These results establish polar
topology as an organizing principle for intrinsic switching and suggest that hidden topological transition states may broadly shape nonequilibrium phase transformations traditionally understood as Landau-type
symmetry breaking.
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Materials Science · Cross-listed from physics.optics
Antimony for broadband nanophotonics across the ultraviolet, visible and infrared
Fernando Chacón-Sánchez, Jacek Wojcik, Marina García Pardo et al. (+5 more)
Semimetal elemental antimony (Sb) nanostructures show great potential for applications where nanophotonic properties play a key role, such as phase-change optical
memories, non-linear optical elements, photothermal therapy
agents, photodetectors and photocatalysts. However, designing advanced Sb-based photonic devices critically requires an accurate and reliable knowledge of the optical response of bulk and nanoscale Sb. Herein, we report for the first time a fully consistent and accurately measured dielectric function for Sb nanoscale films in a wide spectral range from the ultraviolet to the far infrared (4 - 0.04 eV, i.e. ~ 0.3 - 30 $\mu$m), surpassing previous reports that explored a limited spectral range. It is found that the Sb spectral response is driven exclusively by giant interband transitions in the visible up to mid infrared (4 - 0.4 eV, i.e. ~ 0.3 - 3 $\mu$m), and that their contribution dominates over that of free carriers down to 0.12 eV (i.e. ~ 10 $\mu$m). Such spectral response enables Sb nanostructures to display spectrally selective and tunable nanophotonic resonances. First, we showcase interband plasmonic resonances in the visible-to-near infrared for Sb nanogratings. Second, we report giant refractive index dielectric resonances in the mid infrared for nanostructured Sb/dielectric/metal resonant cavities. These findings open a pathway to optimized planar Sb nanoscale designs enabling a tailored light-matter interaction, which will be useful for integrated data, telecom, medical, optoelectronic and energy conversion devices operating in a broad spectral range.
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All authors Fernando Chacón-Sánchez, Jacek Wojcik, Marina García Pardo, Fátima Cabello, Peter Mascher, Fernando Agulló-Rueda, Rosalía Serna, Johann Toudert
Materials Science
A Community-Developed Domain Ontology for Magnetic Materials
Wilfried Hortschitz, Santa Pile, Claas Fillies et al. (+18 more)
Magnetic materials play a crucial role in energy-related technologies, mobility, and sensing, but their complex multiscale behaviour and the coexistence of multiple unit systems pose persistent challenges for data exchange and interpretation. This paper presents a domain ontology for
magnetic materials, developed within the European Union funded
Magnetic Multiscale Modelling Suite (MaMMoS) project and aligned with the Elementary Multiperspective Material Ontology (EMMO). The ontology formalises intrinsic, hysteretic, and microstructural properties across multiple length scales and supports semantic interoperability between simulation tools, databases, and experimental workflows. One key feature of the ontology is its code-based and human-readable structure, enabled through the EMMOntoPy framework, which allows for direct manipulation and versioning without relying on opaque .owl or .ttl files. This facilitates collaborative development and improves transparency. The ontology supports FAIR (Findable, Accessible, Interoperable, Reusable) principles and is openly available for extension by the community. The aim of the MaMMoS project is to foster reproducibility, improve traceability, and promote the adoption of ontology in the magnetism domain. The ontology that has been developed already serves as the foundation for multiple software tools that handle all kinds of
magnetic material data.
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All authors Wilfried Hortschitz, Santa Pile, Claas Fillies, Harald Oezelt, Alexander Kovacs, Hans Fangohr, Samuel J. R. Holt, Martin Lang, Andrea Petrocchi, Swapneel Pathak, Michael P. Adams, Jonas Winkler, Thomas G. Woodcock, William Rigaut, Pierre Le Berre, Nora M. Dempsey, Alena Vishina, M. Nur Hasan, Georgia A. Marchant, Heike C. Herper, Thomas Schrefl
Materials Science
Bottom-up Synthesis of Metastable 2D Hexagonal Copper(I) Iodide on Monolayer and within Bilayer Graphene
David Kaiser, Guobin Jia, Janis Köster et al. (+9 more)
Copper(I) iodide (CuI) is a wide-bandgap
semiconductor crystallizing in the 3D $\gamma$-phase under ambient conditions; its layered van der Waals bulk phase $\beta$-CuI is stable only between 643 and 673 K. The two-dimensional (2D) h-CuI form has been obtained via
liquid-phase exfoliation of mechanochemically prepared precursors and via encapsulation between
graphene sheets, whereas bottom-up growth of 2D h-CuI on open surfaces has not yet been demonstrated. Here, we report a vapor-phase synthesis of h-CuI directly on low-defect, large-area monolayer and within bilayer reduced oxo-
graphene (r-oxo-G) at low temperatures. Using a copper TEM grid as the solid-state precursor for copper, HI-vapor exposure at 40 $\deg$C initiates nucleation, while annealing at 180 $\deg$C promotes the growth of extended h-CuI domains. Aberration-corrected HRTEM resolves the atomic structure, local twist angles, and
lattice anisotropy of the CuI/r-oxo-G nanohybrid, while STEM-EDX yields a Cu:I ratio consistent with 1:1. First-principles calculations show that van der Waals adhesion to
graphene stabilizes the supported hexagonal layer. Under the presented low-temperature precursor conditions, pathways for nucleation of the $\gamma$-phase are not available, allowing the hexagonal phase to form selectively at the
graphene interface. Ab initio molecular dynamics simulations show that the
heterostructure retains its hexagonal
lattice order at 600 K, including on an open monolayer
graphene support. The lateral extent of the growth is limited mainly by remaining interfacial adsorbates. These results establish a route to metastable 2D h-CuI on a chemically inert
graphene template, which may be useful for wide-bandgap electronic and optoelectronic devices.
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All authors David Kaiser, Guobin Jia, Janis Köster, Sadegh Ghaderzadeh, Christian E. Halbig, Siegfried Eigler, Andrey Turchanin, Benjamin Dietzek-Ivanšić, Arkady V. Krasheninnikov, Jonathan Plentz, Elena Besley, Ute Kaiser
Materials Science
Vacancy Order and Physical Properties of a Ternary Compound Fe0.68Pd0.80Te with an {\alpha}-Fe1+xTe-Type Structure
Bingxian Shi, Manyu Wang, Chenglin Shang et al. (+14 more)
We report the identification and characterization of a new compound Fe0.68Pd0.80Te with an {\alpha}-Fe1+xTe prototype structure. Different from the Fe-square net and minor occupancy of interstitial Fe-sites in Fe1+xTe, Fe0.68Pd0.80Te is featured by a Pdsquare net and near 68% occupancy of the corresponding interstitial Fe-sites. Furthermore, noncontact atomic force microscopy and X-ray diffraction provide evidence for the existence of a 3*3*3 Pd-vacancy order in this layered material. A
spin-glass ground state below Tg 40 K is identified via
magnetic characterization. Electrical transport measurements show that Fe0.68Pd0.80Te is a
semiconductor with a very small band gap below 10 meV. It has weak negative magnetoresistance and holelike charge carriers below room temperature. Our results demonstrate its potentials for further exploring various
quantum phenomena.
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All authors Bingxian Shi, Manyu Wang, Chenglin Shang, Yanyan Geng, Yangyang Fan, Xiaoxiao Pei, Li Huang, Daye Xu, Juanjuan Liu, Jinchen Wang, Hongxia Zhang, Hongliang Wang, Lijie Hao, Rui Xu, Zhongyi Lu, Zhihai Cheng, Peng Cheng
Materials Science
Anisotropy of Ultrafast Strain in $V_2O_3$ Thin Films: Out-of-Equilibrium Phase Transitions under Interfacial Clamping
J. Guzman-Brambila, R. Mandal, D. Lea et al. (+9 more)
Ultrafast photoinduced
insulator-to-metal transitions in correlated materials are often mediated by
lattice distortions, yet the role of interfacial
lattice constraints in shaping nonequilibrium pathways remains largely unexplored. We use azimuth-resolved time-resolved X-ray diffraction to track orientation-dependent strain dynamics in granular V$_2$O$_3$ thin films on c-cut sapphire, where thermal-expansion mismatch imposes anisotropic interfacial strain. Across the thermal transition, the azimuthal profile of the (110)$_H$ strain inverts
curvature, providing direct evidence of partial clamping of the hexagonal basal-plane
lattice (a$_H$,b$_H$). After photoexcitation of the antiferromagnetic insulating phase, the structural response remains clamp-limited: weakly constrained grain families reach the full basal-plane contraction characteristic of the metallic-like state, whereas strongly constrained families exhibit a strongly reduced distortion. Fluence-dependent measurements further disentangle transformed fraction from clamping-limited
lattice distortion. Our results show that interfacial clamping acts as a static selector for ultrafast phase switching and provide a general route to quantify anisotropic strain dynamics in
heterostructures.
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All authors J. Guzman-Brambila, R. Mandal, D. Lea, E. Trzop, M. Servol, J. C. Ekström, F. Pawula, J. Tranchant, L. Cario, M. Lorenc, E. Janod, C. Mariette
Materials Science
Correlation enhanced altermagnetism mediated by spin-lattice coupling in CrSb
Charmi Bhalani and Banasree Sadhukhan
Altermagnets (AMs) exhibit momentum-dependent
spin splitting without net magnetization, making them promising platforms for spintronic applications. While the
symmetry and multipolar origins of nonrelativistic altermagnetic
spin splitting (NRASS) are well established, the role of electronic correlations and
spin-
lattice coupling (SLC) in controlling NRASS remain unexplored. In particular, SLC provides a direct pathway for tuning altermagnetism through
lattice degrees of freedom. Here we first investigate the role of electronic correlations on altermagnetic strength in NiAs-type material CrSb using density functional theory (DFT), DFT+$U$, and dynamical mean-field theory (DMFT). We find that increasing electronic correlations substantially enhance NRASS and drive the stabilization of an incommensurate
spin-spiral (SS) state, while dynamical correlations further amplify the
spin splitting through quasiparticle renormalization of the Cr-$3d$ states. We find that the NRASS remains 12.5% larger in DFT+DMFT than in DFT. By evaluating SLC in next step, we establish its direct connection to the
evolution of NRASS and identify SLC as a microscopic descriptor between electronic correlation and enhanced altermagnetism in CrSb. Investigating it in another NiAs-type compound MnTe, we show that the SLC-NRASS correlation is generic across AMs and establish SLC as a microscopic descriptor of altermagnetic strength. Our results provide a unified framework for tuning altermagnetism through the interplay between the electronic correlations and
lattice degrees of freedom.
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Materials Science
Interface-Controlled Phase Stability in Polymorphic HfO$_2$ Revealed by Machine-Learning Atomistic Simulations
Xudong Zhu, Junhong Li and Lixin He
HfO$_2$ exhibits rich polymorphism, and competition among different phases underpins many of its functional properties. Yet bulk free-energy relations alone cannot explain phase selection at mixed-phase boundaries, where interface orientation and structural continuity constrain collective rearrangements. Here, using machine-learning atomistic simulations and a Hf-centered local phase classification scheme, we show that crystallographic interface matching redirects phase competition and accessible transformation pathways. The M(100)/T(100) interface remains pinned as an M/T mixture throughout 3 ns simulations from 300 to 1800 K. M/PO, M/AO, and PO/AO interfaces retain two-phase coexistence up to 900 K, whereas all T/PO interfaces become PO-dominant. At 1800 K, all non-M interfaces become T-dominant, while M-containing interfaces retain a monoclinic majority. Nudged elastic band calculations reveal lower-barrier routes through interface states. For M(100)$\rightarrow$T(100), the interface-mediated route in a long
cell ($\sim$12 nm) yields a barrier of 136.03 meV/f.u., 29.2 % lower than the direct route in a short
cell ($\sim$3 nm). This difference is associated with sequential phase-front motion absent from the short
cell. These results identify phase boundaries as active participants in phase stability and transformation and establish interface orientation and crystallographic matching as variables for stabilizing metastable polymorphs and directing phase conversion in HfO$_2$.
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Materials Science · Cross-listed from cond-mat.str-el
Optically induced metallic state with persistent monoclinic symmetry in NdNiO$_3$
Christian Tzschaschel, Felix Utsch, Qi Song et al. (+6 more)
Understanding whether electronic and structural order remain coupled under nonequilibrium conditions is a central challenge in correlated materials. Here, we simultaneously track
metallicity and
symmetry across the photoinduced
insulator-to-metal transition in NdNiO$_3$ using time-resolved optical reflectivity and
symmetry-sensitive second-harmonic generation. We find that metallic reflectivity emerges at significantly lower excitation fluence than restoration of the orthorhombic high-temperature
symmetry. As a result, optical excitation stabilizes a metastable state that combines the reflectivity of the metallic phase with the monoclinic
symmetry of the insulating phase, revealing an optically induced monoclinic metal. Only at substantially higher fluences does the
symmetry fully recover to that of the high-temperature phase. These results demonstrate a nonequilibrium decoupling of
metallicity and structural
symmetry and establish simultaneous multiprobe spectroscopy as a powerful approach for identifying emergent phases in correlated materials.
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All authors Christian Tzschaschel, Felix Utsch, Qi Song, Spencer Doyle, Grace A. Pan, Charles M. Brooks, Julia A. Mundy, Clemens von Korff Schmising, Stefan Eisebitt
Materials Science · Cross-listed from cond-mat.mes-hall
Enhancing charge stability of Ge quantum well heterostructures via SiGe layer composition engineering
Ding-Ming Huang, Jun-Hang Liu, Han Gao et al. (+10 more)
Composition modulation is a powerful technique for designing materials with tailored properties, fueling the development of advanced
semiconductor devices. In this work, we have implemented this technique into Ge
quantum well
heterostructures, offering a promising avenue to address the critical challenge of charge stability in
spin qubit devices. Harnessing the atomic-scale precision of molecular beam epitaxy, we have engineered the band structure of the SiGe top barrier via graded composition modulation, thereby reducing charge accumulation states at the SiGe-dielectric interface and strengthening the effective confinement to the hole gases in the Ge
quantum wells. The enhanced charge stability of composition-modulated SiGe/Ge
quantum well
heterostructures is confirmed in Hall devices, featuring an enlarged stable gate voltage range. We have further fabricated
quantum dot devices from the composition-modulated SiGe/Ge
quantum well
heterostructures and observed remarkably low charge noise with an averaged amplitude of $0.46\,\mathrm{\mu eV}/\mathrm{\sqrt{Hz}}$ at $1\,\mathrm{Hz}$—the lowest reported value for Ge
quantum wells grown on silicon. This exceptional charge stability of the
quantum dots persists in the few-hole regime, with no observable voltage drift over $\sim$hours. With reduced charge noise and enhanced energy stability, composition-modulated SiGe/Ge
heterostructures exhibit significant potential for applications in building high-performance
quantum devices, including
spin qubits with a long coherence time.
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All authors Ding-Ming Huang, Jun-Hang Liu, Han Gao, Jie-Yin Zhang, Jian-Huan Wang, Fang-Ze Liu, Xin-Yu Zhou, Yi Luo, Bin-Xiao Fu, Xiao-Fei Liu, Ji-Yin Wang, Jian-Jun Zhang, H. Q. Xu
Materials Science
Interplay of spin-lattice and electronic coupling far above Neel ordering in 2D antiferromagnetic CrPS4 and its interface manifestation
Divya Jangra, Binoy Krishna De, Mukesh Kumar Dasoundhi et al. (+13 more)
A short-range
spin correlation driven, strongly intercoupled
spin-
phonon-electronic state far above TN (~38K) is identified in the low dimensional van der Waals antiferromagnet CrPS4. Temperature-dependent Raman spectroscopy reveals
spin-
phonon coupling persisting up to T*~120K, concomitant with local
lattice distortion. The setting of vibronic progression in photoluminescence spectra suggests the strengthening of electron-
phonon coupling around T*. Furthermore, both the electrical transport and optoelectronic response also change significantly at T*. The results indicate that
spin-
phonon coupling above TN in CrPS4 originates from local
lattice distortion induced by short range
magnetic correlations which in turn enhances the electron-
phonon interaction. Furthermore, using a CrPS4/In2Se3
heterostructure, we demonstrate that the anomaly associated with the coupled degrees of freedom in CrPS4 also influences the adjacent In2Se3 layer. The
lattice dynamics of In2Se3 is significantly modified across the
magnetic anomaly of CrPS4, and the coupled dynamics is observed at T*. These interfacial manifestation opens up new possibilities for achieving correlated multifunctionalities in artificially designed
heterostructure.
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All authors Divya Jangra, Binoy Krishna De, Mukesh Kumar Dasoundhi, Sourav Chowdhury, Pragati Sharma, Kartick Biswas, Arup Basak, Dheeraj Kumar Gupta, Koushik chakraborty, Praveen Kumar Velpula, Pavan Nukala, U. Chandni, Arvind Kumar yogi, Mukul Gupta, Markus Hucker, Vasant G. Sathe
Materials Science
High-Performance Scaled P-Type SnOx Transistor by Atomic Layer Deposition with CFET Integration
Ziheng Wang, Wen He, Chen Gu et al. (+8 more)
The development of high-performance p-type oxide
semiconductors is essential for realizing complementary logic for monolithic 3D integration, yet p-type oxide
semiconductors still exhibit substantially inferior performance compared with their n-type counterparts. In this work, we demonstrate high-performance p-type SnOx transistors by atomic layer deposition (ALD), as back-end-of-line compatible devices for monolithic 3D integration. The SnOx transistors exhibit high field-effect mobility of 6.9 cm2/Vs, low subthreshold swing (SS) of 185 mV/dec, decent on/off ratio (ION/IOFF) of 1.8*104 and high bias stability. By scaling the channel length down to 80 nm, a high on-current of 38.7 mA/mm at VDS of -1 V is achieved. It is understood that precursor and reaction engineering to suppress Sn4+ component in SnOx film are the key for performance enhancement. Furthermore, a complementary field-effect transistor with ALD SnOx p-FET vertically stacking on ALD In2O3 n-FET is also demonstrated, achieving maximum voltage gain of 21 V/V at VDD of 4 V. These findings suggest ALD SnOx as a promising candidate for scaled high-performance BEOL p-type transistors.
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All authors Ziheng Wang, Wen He, Chen Gu, Kai Jiang, Liankai Zheng, Jinxiu Zhao, Zhiyu Lin, Xiangjun Liu, Di Geng, Ling Li, Mengwei Si
Materials Science
U-Shaped Fermi-Level Dependence of Point-Defect Aggregation Enthalpy in Silicon
Yin Wu, Xiao Kong and Pai Li
Point defects govern the electronic and structural behavior of silicon, yet their configuration and energy depend on both the charge state and the Fermi level (EF). Using an unbiased global structure search with first-principles calculations, we screened more than 1,500 candidate structures, covering intrinsic defects and C, H, O, N, P, and B impurities in charge states from -2 to +2. The reaction enthalpy of defect aggregation depends on EF in a U shape, being strongest where the net charge transferred during the reaction vanishes and weaker toward both band edges. This U arises because complexes are more charge-neutral than their isolated constituents, so the net charge transfer changes sign across the gap. The point where this sign change occurs is set by the transition levels of the specific defects. For typical reactions, the driving force is tunable by 0.3-0.5 eV, which shifts the
equilibrium complex concentration by five to eight orders of magnitude at room temperature. Our results make the Fermi level a practical lever for defect engineering in as-grown and irradiated silicon.
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Materials Science
Silicon Solar Cell Design for >30% Efficiency via Singlet Fission
Shona McNab, Phoebe Pearce, Pietro P. Altermatt et al. (+8 more)
Singlet fission (SF) materials convert high-energy
photons into multiple charge carriers, providing a route to exceed the efficiency limits of single-junction silicon solar
cells without many of the complexities of multi-junction tandem designs. Following the first demonstration of an SF-enhanced silicon solar
cell in 2025, there is a need to understand how SF materials can be effectively integrated into high-efficiency industrial silicon devices and translated from proof of concept to a manufacturable technology. Using coupled optical and electrical simulations, we assess the efficiency potential of several industrially relevant silicon
cell architectures combined with SF materials. Interdigitated back-contact (IBC)
cells offer the greatest potential for improvement due to unrestricted front-surface access and can achieve efficiencies exceeding 33%. However, performance is highly sensitive to front-surface passivation quality. Appropriate silicon design, particularly controlled surface doping and fixed interfacial charge, can mitigate recombination losses and relax passivation requirements for ultra-thin
exciton-transfer layers.
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All authors Shona McNab, Phoebe Pearce, Pietro P. Altermatt, Jingnan Tong, Ruy Sebastian Bonilla, Timothy W. Schmidt, Murad J. Y. Tayebjee, Bram Hoex, Alison Ciesla, Michael P. Nielsen, Nicholas J. Ekins Daukes
Materials Science
A model of grain growth in UN integrating molecular dynamics, phase-field modeling, and uncertainty quantification
Mohamed AbdulHameed, Fadel M. Nasr, Wen Jiang et al. (+2 more)
Grain growth kinetics and grain-boundary (GB) properties in uranium mononitride (UN) are investigated through an integrated multiscale framework combining molecular dynamics (MD), phase-field modeling, and surrogate-assisted uncertainty quantification. MD simulations yield GB energies for 27 symmetric tilt boundaries from 0–2000~K, which are consistent with available DFT values. The average GB energy is nearly temperature-independent below 1000~K and increases at higher temperatures. A mechanistic pore-drag model applied to the only available grain growth
dataset for actinide nitrides yields a mobility reduction factor of $s \approx 0.93$–$0.99$, statistically indistinguishable from unity, confirming that pore drag is negligible under the experimental conditions. The intrinsic GB mobility is therefore extracted directly from the effective mobility, yielding $M_0 = 2.05\times10^{-15}$~m$^4$/(J$\cdot$s) and $Q_M = 0.89$~eV. Phase-field simulations conducted from 1500–2000~K confirm normal
curvature-driven grain growth, with grain size distributions converging to the Hillert-like form. A surrogate-assisted global sensitivity analysis—combining principal component analysis, Gaussian process regression, and Sobol decomposition—reveals that the mobility prefactor $M_0$ dominates output variance at all times, followed by the activation energy $Q_M$, while the GB energy $\gamma$ contributes minimally. These results establish the first quantitative grain growth framework for UN and identify the reduction of uncertainty in $M_0$ and $Q_M$ as the highest-priority target for future experimental efforts.
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All authors Mohamed AbdulHameed, Fadel M. Nasr, Wen Jiang, Mahmoud Yaseen, Benjamin Beeler