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Physics Condensed Matter Materials Science

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Sunday 1 March

Materials Science · Cross-listed from physics.app-ph

Efficacy of 3D-Printed chitosan-cerium oxide dressings coated with vancomycin-loaded alginate for chronic wounds management

Sharareh Shahroudi, Amir Parvinnasab, Erfan Salahinejad et al. (+3 more)

Multifunctional wound dressings with antibacterial and antioxidant properties hold significant promise for treating chronic wounds; however, achieving a balance of these characteristics while maintaining biocompatibility is challenging. To enhance this balance, this study focuses on the design and development of 3D-printed chitosan-matrix composite scaffolds, which are incorporated with varying amounts of cerium oxide nanoparticles (0, 1, 3, 5, and 7 wt%) and subsequently coated with a vancomycin-loaded alginate layer. The structure, antibiotic drug delivery kinetics, biodegradation, swelling, biocompatibility, antibacterial, antioxidant, and cell migration behaviors of the fabricated dressings were evaluated in-vitro. The findings reveal that all of the formulations demonstrated a robust antibacterial effect against S. aureus bacterial strains in disk diffusion tests. Furthermore, the dressings containing cerium oxide nanoparticles exhibited proper antioxidant capabilities, with over 78.1% reactive oxygen species (ROS) scavenging efficiency achieved with 7% cerium oxide nanoparticles. The sample containing 5% cerium oxide nanoparticles was identified as the optimal formulation, characterized by the most favorable cell biocompatibility, an ROS scavenging ability of over 73.4%, and the potential to close the wound bed within 24 h. This study highlights that these dressings are promising for managing chronic wounds by preventing infection and oxidative stress in a correct therapeutic sequence.
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All authors Sharareh Shahroudi, Amir Parvinnasab, Erfan Salahinejad, Shaghayegh Abdi, Sarah Rajabi, Lobat Tayebi

Materials Science · Cross-listed from physics.geo-ph

Superhydrophobic Sand Mulch Shifts Soil Evaporation from Temperature-Controlled to Diffusion-Limited Regimes

Amr Al-Zu'bi, Muhammad Subkhi Sadullah, Jiaqi Zheng et al. (+3 more)

In hot arid and semi-arid regions, substantial irrigation water is lost through surface evaporation under intense solar irradiation and high temperatures, limiting freshwater sustainability and crop productivity. Superhydrophobic Sand (SHS) mulch, a plastic-free, bio-inspired technology, has been proposed as a dry diffusion barrier to suppress evaporative losses. Here, we combine controlled column experiments with heat and mass transfer modeling to quantify how SHS thickness and soil properties govern evaporation under fixed irradiation. Relative to unmulched controls, a 5 mm SHS layer reduced evaporative flux by 65$\%$ in fine sand and 63$\%$ in coarse sand, while a 10 mm layer reduced flux by 83$\%$ and 70$\%$, respectively. Notably, soil-type trends reversed after mulching: although unmulched fine sand exhibited 37.5$\%$ higher evaporation than coarse sand, application of a 10 mm SHS layer reduced fine-sand evaporation to 40$\%$ below that of coarse sand. To explain this counterintuitive behavior, we developed a coupled heat and vapor transport model incorporating soil thermophysical properties and diffusion through the porous mulch layer. The model accurately predicted steady-state temperature profiles and evaporation rates for both mulched and unmulched systems. Our results show that SHS mulch shifts evaporation from a surface-temperature-controlled regime to a diffusion-limited regime governed by mulch thickness and soil thermal conductivity. This mechanistic understanding clarifies the performance of SHS and supports its potential to enhance irrigation efficiency in arid agricultural and landscaping applications.
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All authors Amr Al-Zu'bi, Muhammad Subkhi Sadullah, Jiaqi Zheng, Lisa Exposito, Adair Gallo Jr., Himanshu Mishra

Materials Science

Non-collinear Altermagnetic Phases in the Mott Insulator NiS$_2$

Mengli Hu, Mikel I. Iraola, Paul McClarty et al. (+2 more)

Altermagnets (A$\ell$Ms) constitute a novel family of magnetic materials characterized by the absence of net magnetization and the presence of spin-polarized band structures. Whereas A$\ell$M phases were initially proposed in collinear structures, the recently discovered noncollinear chiral A$\ell$Ms stand out for their distinct hedgehog spin texture and multifunctionality in spintronics. In this work, we deepen the characterization of these systems by constructing a Landau theory for noncollinear achiral A$\ell$Ms. Furthermore, we demonstrate that the achiral symmetry of the crystal is reflected in the spin texture in reciprocal space, which presents only spatial-even multipoles. These multipoles, distinguished from those in collinear A$\ell$Ms via the high-order secondary order parameters, can couple to many phenomena such as the spin Hall effect and piezomagnetic effect. To exemplify our theory, we study the noncollinear achiral magnet NiS$_2$ within the framework of altermagnetism, showcasing both spin Hall and piezomagnetic effects in a prototypical correlated Mott insulator that provides an ideal platform to explore the interplay between strong electronic correlations, crystal symmetry, and altermagnetic spin textures. Interestingly, altermagnetism emerges in two magnetic ordered phases of NiS$_2$ upon lowering the temperature. The non-collinearity strengthens the robustness of A$\ell$M order, as the anti-ferromagnetism induced by the strong correlations will not impose effective time-reversal symmetry as in the collinear case. Our results suggest non-collinear achiral A$\ell$Ms as a promising platform for spintronics applications due to the potential to achieve various spin textures with different magnetic orders.
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All authors Mengli Hu, Mikel I. Iraola, Paul McClarty, Jeroen van den Brink, Maia G. Vergniory

Materials Science

The completed High-Low method for interface state density analysis in MOS capacitors

Brian D. Rummel, Sarit Dhar and Robert J. Kaplar

Interface state densities, $D_{IT}$, in metal-oxide-semiconductor (MOS) capacitors are rarely reported in the accumulation energy range. It is recognized that the determination of $D_{IT}$ in accumulation is fundamentally obscured by small inaccuracies in the user-defined oxide capacitance, $C_{OX}$. This source of error prevents the High-Low frequency technique from reporting accumulation $D_{IT}$, even for sufficiently fast high-frequency measurements. To resolve this, an electrostatic constraint that is uniquely satisfied by a physically consistent $C_{OX}$ is derived from the established theory, thereby completing the High-Low framework. The "completed" framework's theoretical validity is confirmed using simulated capacitance data for an n-SiC MOS structure, and the method's frequency limitations are demonstrated. This analytical advancement ensures a physically consistent extraction of $D_{IT}$ near the band edge, overcoming a fundamental limitation in MOS capacitor characterization.
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Materials Science · Cross-listed from physics.comp-ph

NEP-CG and NEP-AACG: Efficient coarse-grained and multiscale all-atom-coarse-grained neuroevolution potentials

Zheyong Fan, Wenjun Zhang, Zhenhao Zhang et al. (+3 more)

Machine-learned coarse-grained (CG) models often suffer from noisy training data, limiting their accuracy and transferability. We propose a method to generate low-noise training data based on the potential of mean force by constraining CG beads during atomistic simulations and accumulating time-averaged forces. Implemented within the neuroevolution potential (NEP) framework, our approach achieves training accuracy comparable to atomistic models trained on density functional theory data. For liquid water, the NEP-CG model accurately reproduces densities from 1 bar to 1 GPa, successfully extrapolating beyond the 0.5 GPa training limit, with a virial correction essential for the correct equation of state. For an anisotropic C$_{60}$ monolayer, distinguishing crystallographically distinct bead types reduces stress errors by an order of magnitude and captures directional thermal conductivity. We further introduce a multiscale NEP-AACG model integrating all-atom (AA) and CG degrees of freedom, demonstrated for gold nanowire fracture at an experimentally relevant strain rate. Computational speeds for NEP-CG models reach hundreds to thousands of ns/day using a single consumer-grade GPU. This work provides a robust framework for constructing accurate, transferable, and efficient CG models across diverse systems.
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All authors Zheyong Fan, Wenjun Zhang, Zhenhao Zhang, Ke Xu, Xuecheng Shao, Haikuan Dong

Materials Science

Networking Molecular Quantum Emitters on a Single Chain : From Single to Cooperative Emitters

Jean-Baptiste Marceau, Juliette Le Balle, Christel Poujol et al. (+4 more)

Engineering light-matter interactions between multiple free-space quantum emitters is a central challenge for scalable quantum photonic technologies. In particular, accessing regimes of coherent emitter-emitter interactions, where several emitters are coupled through a shared electromagnetic environment, is essential for coherent emission and quantum functionalities. Such interactions require precise control over emitter separation and stabilization at sub-wavelength distances, a level of spatial organization that remains extremely difficult to achieve at the molecular scale in solid-state systems. Here we introduce Encoded Quantum Chains (EQC), a one-dimensional architecture in which cooperative radiative behaviour is programmed through spatial encoding of identical molecular emitters. Organic emitters and inert spacer molecules are co-encapsulated inside dielectric boron nitride nanotubes (BNNTs), enabling statistical control of intermolecular spacing from nanometres to micrometres while enforcing dipole alignment and one-dimensional confinement. Time-resolved fluorescence under ambient conditions reveals accelerated radiative decay, enhanced emission rates per emitter, and the emergence of non-mono-exponential dynamics as spacing falls below the optical wavelength, consistent with cooperative radiative states in one dimension. Bundling of EQCs enables coupling between emitters in neighbouring BNNTs, driving a dimensional crossover toward higher-dimensional delocalisation of the excitation. This modular building-block approach provides a scalable route to engineer light-matter interactions and many-body optical phenomena in confined molecular systems, opening new opportunities for distributed single-photon sources, programmable quantum emitters, and photonic architectures for quantum technologies.
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All authors Jean-Baptiste Marceau, Juliette Le Balle, Christel Poujol, Frédéric Fossard, Annick Loiseau, Gaëlle Recher, Etienne Gaufrès

Materials Science

Design of 2D V<sub>6</sub>S<sub>n</sub>Se<sub>6-n</sub>Cl<sub>6</sub> (n=0, 2, 3, 5) with multilayer kagome lattice and ultrahigh electron mobility

Xing-Yu Wang, En-Qi Bao, Su-Yang Shen et al. (+2 more)

Two-dimensional (2D) kagome materials have attracted considerable attention due to their unique electronic properties. Based on first-principles calculations and employing the "1+3" design strategy, we designed a class of composition-tunable 2D multilayer kagome materials, V<sub>6</sub>S<sub>n</sub>Se<sub>6-n</sub>Cl<sub>6</sub>, and identified four stable structures: V<sub>6</sub>Se<sub>6</sub>Cl<sub>6</sub>, V<sub>6</sub>S<sub>2</sub>Se<sub>4</sub>Cl<sub>6</sub>, V<sub>6</sub>S<sub>3</sub>Se<sub>3</sub>Cl<sub>6</sub>, and V<sub>6</sub>S<sub>5</sub>Se<sub>1</sub>Cl<sub>6</sub>. 2D V<sub>6</sub>S<sub>n</sub>Se<sub>6-n</sub>Cl<sub>6</sub> possesses three kagome layers, two of which are vanadium-based kagome layers, and the other is a sulfur or selenium atomic layer. Electronic structure analysis reveals that 2D V<sub>6</sub>S<sub>n</sub>Se<sub>6-n</sub>Cl<sub>6</sub> is a narrow direct-bandgap semiconductor with a bandgap ranging from 0.568 to 0.742 eV, and exhibits ultrahigh electron mobility up to 4*10<sup>4</sup> cm<sup>2</sup>V<sup>-1</sup>s<sup>-1</sup> . Orbital analysis further demonstrates that the bands contributed by the V-based kagome layers form flat bands and Dirac cones below the Fermi level, and show a relatively high Fermi velocity. In summary, 2D V<sub>6</sub>S<sub>n</sub>Se<sub>6-n</sub>Cl<sub>6</sub> provides an excellent platform for kagome physics research and the fabrication of nanoelectronic devices, adaptable to various device scenarios.
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All authors Xing-Yu Wang, En-Qi Bao, Su-Yang Shen, Jun-Hui Yuan, Jiafu Wang

Materials Science

Symmetry-Indicated Time-Reversal-Doubled Axion Insulators

Yue Xie, Haohao Sheng, Quansheng Wu et al. (+4 more)

The axion insulator exhibits a topological magnetoelectric effect characterized by an axion angle $\theta=\pi$, while the time-reversal-doubled axion insulator (T-DAXI) can be viewed as two copies of an axion insulator related by time-reversal symmetry. In this work, we show that a topological crystalline insulator with nonsymmorphic glide or screw symmetry hosts the T-DAXI phase. The spin-resolved topology of the T-DAXI phase is guaranteed by the nonsymmorphic symmetry invariant $\delta_g=1$ or $\delta_s=1$ in certain spin directions. In this phase, the partial axion angles are quantized to $\pi$, and the gapped surfaces realize half-quantized quantum spin Hall states. By applying an external magnetic field along the $z$ direction, electrons with opposite spins accumulate on opposite $(001)$ surfaces, producing a topological spin polarization in real space. When the magnetic field is time-periodic, this leads to an alternating spin current detectable in experiment. Using $\mathrm{\textit{ab initio}}$ calculations, we demonstrate that mixed bismuth monohalides Bi4Br3I and Bi4BrI3 realize the nonsymmorphic T-DAXI with $\delta_g=\delta_s=1$. Our findings not only reveal the symmetry-enforced T-DAXIs in nonsymmorphic topological crystalline insulators, but also introduce the spin magnetoelectric effect as a novel topological spin response.
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All authors Yue Xie, Haohao Sheng, Quansheng Wu, Xi Dai, Zhong Fang, Hongming Weng, Zhijun Wang

Materials Science · Cross-listed from cond-mat.supr-con

Non-reciprocal properties of 2D superconductors

Xingrong Ren, Huiqing Ye and Tian Le

Two-dimensional (2D) superconductors, characterized by their inherent quantum confinement, strong spin-orbit coupling, and diverse forms of symmetry breaking, provide an ideal platform for exploring novel quantum transport phenomena. This review summarizes recent experimental progress in the non-reciprocal properties of 2D superconductors, focusing on second harmonic resistance in the resistive superconducting state and the supercurrent diode effect (SDE) in the dissipationless superconducting regime. We discuss the various origins of these phenomena, distinguishing between intrinsic mechanisms, such as finite-momentum Cooper pairing, and extrinsic mechanisms driven by asymmetric vortex dynamics and device geometry. We present a systematic classification of zero-field SDE into polarity-reversed and polarity-locked behaviors, a distinction governed by the interplay between intrinsic time-reversal symmetry breaking and external magnetic response. Furthermore, we examine how the efficiency and polarity of SDE are modulated by tuning parameters including magnetic/electric fields, strain, device geometry, thermodynamic conditions, and microwave irradiation. We conclude by highlighting the application potential of these tunable diodes in high-efficiency rectification, superconducting logic, and neuromorphic computing.
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Materials Science

Nanoscale imaging reveals critical plating and stripping mechanisms in anode-free lithium and sodium solid-state batteries

J. Diaz-Sanchez, P. Hernandez-Martin, N. Kwiatek-Maroszek et al. (+12 more)

Achieving reversible anode-free solid-state batteries hinges on controlling alkali-metal plating and stripping at buried interfaces, yet the underlying nanoscale mechanisms remain unresolved. Here we introduce virtual-electrode low-energy electron microscopy (VE-LEEM), an imaging platform that enables nanoscale visualization of anode formation and dissolution by combining electron beam-induced plating with ultraviolet-driven stripping. By integrating VE LEEM with synchrotron-based photoemission electron microscopy and atomic force microscopy, we track the chemical and morphological evolution of Li and Na anodes during cycling. We uncover a shared dynamic scaling regime governing anode growth, analogous to high mobility thin film deposition, but emerging through distinct morphological pathways dictated by metal-specific surface energetics. This universal scaling behaviour establishes a transferable quantitative framework for comparing anode-free plating across chemistries. In contrast, stripping proceeds through sequential grain-boundary unzipping and cluster decay mechanisms, demonstrating that dissolution is intrinsically asymmetric with respect to plating and leaves behind a persistent interfacial residual layer. These results overturn the common assumption of mirrored plating-stripping dynamics and identify interfacial and grain boundary energetics as fundamental constraints on reversibility. VE LEEM thus provides a general route to resolve buried electrochemical interfaces at the nanoscale and establishes an energetic framework to guide the design of durable, high energy anode free solid state batteries.
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All authors J. Diaz-Sanchez, P. Hernandez-Martin, N. Kwiatek-Maroszek, H.R. Bratlie, R. Anton, A. Lowack, A. Galindo, K. Kataoka, E. Vasco, K. Nikolowski, D. Rettenwander, E.G. Michel, M.A. Nino, M. Foerster, C. Polop

Materials Science

Unfolding Bloch States in Disordered Systems

T. Thuy Hoang, Kunihiro Yananose, Sungjong Woo et al. (+4 more)

In crystalline solids, disorder breaks translational symmetry and obscures k-resolved Bloch states, limiting an accurate description of wavefunction-based observables. In this work, we present a method that unfolds not only the band structures but also the corresponding Bloch states in disordered systems, going beyond conventional band-unfolding techniques. As a prototype application, we study defective graphene and demonstrate the capabilities by capturing key wavefunction-level responses, including disorder-driven redistribution of Berry curvature.
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All authors T. Thuy Hoang, Kunihiro Yananose, Sungjong Woo, Seongjin Ahn, Dong Han, Xian-Bin Li, Junhyeok Bang

Materials Science

Experimental Powder X-ray Diffraction Crystal Structure Determination with RealPXRD-Solver

Qi Li, Mingyu Guo, Rui Jiao et al. (+14 more)

Determining crystal structures from experimental powder X-ray diffraction data remains challenging because peak overlap, preferred orientation, and impurity phases obscure atomic arrangements. We present RealPXRD-Solver, a generative model trained on 6,250,238 theoretical structures with experiment-mimicking augmentations and a universal encoder of d-spacing–intensity fingerprints, enabling both lattice-conditioned and lattice-free inference. RealPXRD-Solver reaches a 98.3% Top-20 match rate on a 10,000-structure theoretical benchmark and achieves Top-1/Top-20 accuracies of 77.9%/91.9% on CNRS and 78.8%/92.9% on RRUFF experimental datasets, and it solved 39 previously unreported Powder Diffraction File entries.
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All authors Qi Li, Mingyu Guo, Rui Jiao, Jing Gao, Fanjie Xu, Haonan Xue, Weixiong Zhang, Wenbing Huang, Junchi Yan, Linfeng Zhang, Cheng Wang, Zhuang Yan, Guolin Ke, Weinan E, Zhiyong Tang, Shifeng Jin, Lin Yao

Materials Science

Stress-driven dynamic evolution of core-shell structured cavities with H and He in BCC-Fe under fusion conditions

Jin Wang, Fengping Luo, Yiheng Chen et al. (+11 more)

Understanding the dynamic behavior of microstructures formed under fusion conditions is critical for designing high-performance structural materials for fusion reactors. Under fusion conditions, cavities of core-shell structures are formed due to the interaction between irradiation-induced vacancies and H and He atoms produced via transmutation. In this study, thermodynamic analysis and molecular dynamics simulations are combined to investigate the atomic-scale mechanisms and dynamic response of core-shell cavities formed in BCC-Fe under applied stress/strain fields. The thermodynamic analysis provides both the foundational reference for cavity structures under fusion neutron irradiation and the initial configurations for atomistic simulations. Building on this framework, atomic-scale simulations demonstrate that H and He play a decisive role in the stress-strain response and the evolution of elastic-plastic deformation within the cavities. In core-shell configurations, H atoms serve a function analogous to that in He-filled cavities, synergistically interacting with He to induce cavity deformation under mechanical loading.
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All authors Jin Wang, Fengping Luo, Yiheng Chen, Denghuang Chen, Bowen Zhang, Yuxin Liu, Guangyu Wang, Yunbiao Zhao, Sheng Mao, Mohan Chen, Hong-Bo Zhou, Jianming Xue, Yugang Wang, Chenxu Wang

Materials Science

Relationship between local hydride ion dynamics and ionic conductivity in LaH$_{3-2x}$O$_x$ inferred from muon study

M. Hiraishi, S. Takeshita, H. Okabe et al. (+6 more)

We performed muon spin rotation and relaxation ($\mu$SR) experiments to investigate the microscopic mechanism behind the high ionic conductivity ($\sigma$) exhibited by hydride (H$^-$) ions in lanthanum hydroxide LaH$_{3-2x}$O$_x$. The $\mu$SR spectra observed at 5–300 K in a sample with $x\approx0.25$ consist primarily of two components which are attributed to muons occupying tetrahedral (Tet) and octahedral (Oct) sites common to H$^-$. The spectra also indicate that muons at the Oct sites (Mu$_{\rm O}$) appear nearly stationary in the time scale of $\mu$SR ($\sim$10$^{-5}$ s), whereas those at the Tet sites (Mu$_{\rm T}$) are subject to the fluctuating local fields. The cusp-like peak in the fluctuation rate around 160 K and the decrease in linewidth at higher temperatures probed by Mu$_{\rm T}$ suggest that the jump motion of both Mu$_{\rm T}$ (via the vacant Oct sites) and surrounding Oct-site H$^-$ contributes to spin relaxation and that the fluctuation frequency is widely distributed. These results indicate that the implanted Mu behave as Mu$^-$ and that the jump motion of Mu$^-$/H$^-$ is restricted by the availability of nearby vacant sites. On the other hand, the activation energy for the jump is estimated to be 0.11(3) eV, which is significantly different from $\sim$1.3 eV evaluated from the temperature dependence of $\sigma$ at high temperatures ($\gtrsim400$ K). In our attempt to resolve this discrepancy, we discuss problems inherent in interpreting $\sigma$ using the Arrhenius equation, and demonstrate that the behavior of H$^-$ ions can be better explained as a viscous fluid exhibiting a glass transition.
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All authors M. Hiraishi, S. Takeshita, H. Okabe, K. M. Kojima, A. Koda, S. Iimura, K. Fukui, H. Hosono, R. Kadono

Materials Science

Pressure-induced hypercoordination of iodine and dimerization of I2O6H in strontium di-iodate hydrogen-iodate (Sr(IO3)2HIO3)

D. Errandonea, H. Osman, R. Turnbull et al. (+8 more)

In this work, we report evidence of pressure-induced changes in the crystal structure of Sr(IO3)2HIO3 connected to changes the coordination of the iodine atom and the of the configuration of HIO3 and IO3 units. The changes favor iodine hypercoordination and happen in two steps on sample compression. Firstly, at 2.5 GPa, [HIO3]-[IO3] complexes are formed, and secondly, at 4.5 GPa, these complexes form dimers of [HIO3]-[IO3]-[IO3]-[HIO3]. The evidence is obtained from a combined experimental and theoretical study performed up to 20 GPa. Synchrotron powder X-ray diffraction, Raman spectroscopy, and optical-absorption experiments have been complemented with density-functional theory calculations, including the study of the topology of the electron density. The changes observed in the crystal structure are related to the transformation of secondary (halogen) bonds into electron-deficient multicenter bonds. The paper also discusses the effect of pressure on the compressibility of the Sr(IO3)2HIO3 crystal structure, its phonons, the electronic band gap, and the refractive index. Sr(IO3)2HIO3 was found to be highly compressible with an anisotropic compressibility. The softening of the internal I-O vibrations of IO3 units was also observed, together with a decrease of the band-gap energy (from 4.1 eV at 0 GPa to 3.7 eV at 20 GPa), a band-gap crossing, and a change in the topology of the band structure, with Sr(IO3)2HIO3 transforming from a direct gap semiconductor at 0 GPa to an indirect gap semiconductor beyond 6 GPa.
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All authors D. Errandonea, H. Osman, R. Turnbull, D. Diaz-Anichtchenko, A. Liang, J. Sanchez-Martin, C. Popescu, D. Jiang, H. Song, Y. Wang, F.J. Manjon

Saturday 28 February

Materials Science · Cross-listed from physics.geo-ph

High Resolution Microscopy and Raman Spectroscopic Studies on the Freshest Mukundpura Meteorite, Rajasthan, India: Presence of Nanodiamond

D. Chandrasekharam, U. Govind, R. P. Tripathi et al. (+4 more)

Carbonaceous Chondrites have special significance in the stellar evolution and in particular in the evolution of life on earth. The carbonaceous meteorite that fell in Mukundpura village, Jaipur, Rajasthan on 6th June 2017 is one such rare CM2 (Carbonaceous Chondrite) carbonaceous meteorite. We carried out high resolution scanning and transmission electron microscopic (TEM) studies on typical thin sections, showing abundant grains of iridium (Ir), pentlandite (NiS), and more interestingly crystalline carbon (C). These crystallite carbon grains resemble nanodiamond like signature in the freshest Mukundpura meteorite. The high-resolution Raman spectroscopic measurements are carried out on the crystalline carbon grains, showing well resolved three distinct peaks with a vibrational mode at 1315 cm-1, with the onset of a weak vibrational mode at 1150 cm^-1, substantiating the observation of nanocrystalline diamond in Mukundpura meteorite. The broad peak centered at 1360 cm^-1 and 1575 cm^-1 (as an average), suggest the presence of graphitic carbon as well together with apparent presence of nanocrystalline diamond. The average size of nanocrystalline diamond is ~ 3-5 nm. High iridium content in this meteorite supports the meteoric impact related iridium anomaly in geological stratigraphic boundaries (e.g.Cretaceous-Tertiary boundary) that has caused mass extinction of flora and fauna.
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All authors D. Chandrasekharam, U. Govind, R. P. Tripathi, T. H. Amir, K. M. Sairam, D. B. E. Rafal, A. Dixit

Materials Science

Anomalous Crystallinity and Magnetism in Chemically Disordered Coherent Heterostructures

Saeed S. I. Almishal, Sai Venkata Gayathri Ayyagari, Aaron Pearre et al. (+9 more)

High-entropy oxide (HEO) thin films uniquely superimpose exceptional chemical disorder with exceptional crystalline quality and coherence - an intersection we term anomalous crystallinity that arises from coupled structural, chemical, and valence degrees of freedom unique to the entropy-stabilized condition. Here, we demonstrate unexpected and predictive control of this state using formulation, epitaxial constraints, and kinetic arrest of metastable macrostates. Specifically, aliovalent cation substitutions, tightly controlled substrate temperatures, and conditions favoring significant adatom kinetic energy, can program the out-of-plane lattice parameter of coherent rock salt HEOs while preserving in-plane epitaxial pinning to MgO. Lattice strains exceeding 5% can be stabilized in multilayer heterostructures using this approach, where 3+ cations compensated by cation vacancies predominate the defect chemistry landscape. We highlight the exemplar (Sc,Mg,Co,Ni,Cu,Zn)O/(Cr,Mg,Co,Ni,Cu,Zn)O (JSc/JCr) system where Sc and Cr substitution into the rock salt structure produces pseudomorphic heterostructures between individual antiferromagnets exhibiting exceptional strain and abrupt interfaces across which the Co valence switches from mostly 2+ to an even 2+/3+ mixture. These unprecedented valence interfaces are accompanied by a 2x exchange bias boost compared to single-layer constituents, that could be attributed to enhanced uncompensated spins in the layers themselves or around the buried JSc/JCr interface. These results establish pseudomorphic valence interfaces with anomalous crystallinity as a source of new magnetic macrostates that host emergent magnetic and spintronic functionality.
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All authors Saeed S. I. Almishal, Sai Venkata Gayathri Ayyagari, Aaron Pearre, Pat Kezer, Matthew Furst, Christina M. Rost, Binghai Yan, Nasim Alem, Timothy Charlton, Zhiqiang Mao, John T. Heron, Jon-Paul Maria

Materials Science · Cross-listed from cond-mat.stat-mech

Simple models for mesoscopic systems: from slender structures to stochastic resetting

Gregorio García-Valladares

The objective of this thesis is to advance the understanding of complex physical phenomena through the lens of statistical physics. Specifically, it addresses two fundamental questions: What types of interactions can induce buckling of slender structures when their temperature is increased? And, how can we devise an optimal strategy for locating a hidden target? The thesis is divided into two distinct parts, both employing mesoscopic descriptions – neither fully microscopic nor fully macroscopic – to capture the essential interactions and behaviours that qualitatively govern the phenomena under investigation. In the first part, we examine the buckling behavior of low-dimensional materials under thermal load. To this end, we develop a comprehensive model that characterises the system using a minimal setup for mimicking: (i) elastic and electronic degrees of freedom, and (ii) coupling between the elastic and the electronic modes. In the second part, we investigate stochastic resetting processes as a means to formulate efficient search strategies. We explore various resetting mechanisms to understand how to optimise the search performance in real scenarios, where: (i) resetting involves a finite cost, and (ii) the target location is only partially known.
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Materials Science

Competing adsorption of H and CO on Pd-alloy surfaces: Mechanistic insight into the mitigating effect of Cu on CO poisoning

Pernilla Ekborg-Tanner and Paul Erhart

Multi-component alloys offer broad tunability for addressing challenges in materials science, but their vast configurational space makes their surface chemistry highly sensitive to operating conditions, for example through adsorption and segregation. Here, we study Pd-Au-Cu alloy surfaces in H$_2$ and CO environments motivated by their use in H technologies, in particular plasmonic H$_2$ sensing, where alloying can mitigate limitations intrinsic to Pd such as hysteresis and CO poisoning. Modeling multicomponent surfaces with multiple adsorbate species under realistic conditions is challenging. To this end, we establish an accurate and efficient framework that combines machine-learned interatomic potentials trained on density functional theory data to generate training data for cluster expansions with effectively no limitations on training set size. By constructing continuous surface phase diagrams for H-CO coadsorption we find that coadsorption under operating conditions is governed primarily by the H coverage during annealing. Au-rich surfaces, formed under H-poor conditions, suppress both CO and H adsorption, while H-rich conditions yield Pd-rich surfaces that maintain higher H coverages compared to Pd at relevant CO partial pressures, indicating improved CO poisoning resistance. This effect is insensitive to relative amounts of Au and Cu, despite experimental evidence of the mitigating effect of specifically Cu on CO poisoning. Kinetic barriers for dilute alloy surfaces indicate that absorption pathways near Au are highly unfavorable, while Cu leave the energetics unchanged compared to pure Pd. This finding suggests that Cu in the surface region provides viable pathways to shuttle H into the material when Pd-dominated paths are blocked by CO.
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Materials Science

Mechanically Assisted Symmetry Reconstruction for Extraordinary Piezoelectricity

Jinhui Fan, Chonghe Wang, Xiaoyan Lu et al. (+16 more)

Active symmetry control - a central challenge in materials science, particularly in ferroelectrics - is achieved via mechanically assisted poling (MAP) guided by thermodynamics and phase - field modeling. This approach yields extraordinary piezoelectric coefficients (about 5,000 pC/N at 24 degC; 11,700 pC/N at 58 degC) together with about 65% optical transmittance in a classic relaxor ferroelectric, Pb(Mg1/3Nb2/3)O3-PbTiO3. Mechanical suppression of undesirable phases stabilizes a reconstructed symmetry with highly ordered domains, verified by multiple characterization techniques. The strategy is validated across several distinct ferroelectric systems. To demonstrate its practical utility, we fabricate a transparent dual-modal wearable sensor integrating continuous blood pressure monitoring via piezoelectricity with photoplethysmographic SpO2 detection, enabling high-fidelity physiological tracking. This work establishes mechanically assisted symmetry reconstruction as a pathway to multifunctional optoelectronic materials and compact wearable health technologies.
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All authors Jinhui Fan, Chonghe Wang, Xiaoyan Lu, Yunpeng Ma, Zijian Hong, Yuzhao Qi, Yanzhe Dong, Xiaoyue Zhang, Chuchu Yang, Yongchun Zou, Xu Zheng, Xiaolong Li, Qian Li, Xiang Xu, Si-Young Choi, Jiyan Dai, Wenwu Cao, Dragan Damjanovic, Hui Li

Materials Science

Coupled Real- and Momentum-Space Topology in Symmetry-Locked Bilayer Altermagnet

Shuo Zhang, Zijie Fu, Lixiu Guan et al. (+3 more)

Integrating real-space topological spin textures with momentum-space topological electronic states within a single altermagnetic system has remained a persistent challenge. Here, we introduce a symmetry-locked bilayer altermagnet that concurrently hosts d-wave altermagnetism, momentum-space topology, and stable antiskyrmions. In momentum-space, it enables strain-triggered transitions to an antiferromagnetic Weyl semimetal phase, where the Néel vector acts as a switch for spin-layer-polarized quantum anomalous Hall and Weyl states, alongside coupled topological states and valley polarization effects. In real-space, the formation of interlayer co-directional and locked in-plane Dzyaloshinskii-Moriya interactions facilitates the creation of coupled antiskyrmion pairs with compensated topological charges. This locking symmetry fully cancels the transverse Magnus forces, resulting in current-driven, strictly longitudinal motion of antiskyrmions without any Hall-like deflection. Our work establishes a robust platform for dual-space topological magnetism and offers a definitive solution to the vanishing Hall angle in charge-neutral antiskyrmions, opening pathways toward high-density, low-power topological spintronics.
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All authors Shuo Zhang, Zijie Fu, Lixiu Guan, Yirui Du, Linyang Li, Junguang Tao

Materials Science

Deformation mechanisms and compressive response of NbTaTiZr alloy via machine learning potentials

Hongyang Liu, Bo Chen, Rong Chen et al. (+2 more)

Refractory multi-principal element alloys (MPEAs) are key research focus for excellent high-temp properties and engineering potential. Deformation mechanisms/mechanical behaviors of quaternary NbTaTiZr MPEA under high strain rates/extreme temps remain unclear. We built a variable-composition ML potential for NbTaTiZr, combined with MD simulations to study effects of crystal orientation, strain rate, temp, composition on compressive mechanics. NbTaTiZr shows structural/mechanical anisotropy in compression [111] max yield strength, [110] min (prone to twinning), [100] via local disorder/dislocation slip (dominant 1/2<111> dislocations). At 10^10 s^-1, yield strength rises sharply, disordered structures increase; high strain rates suppress dislocations to promote disordering. Retains high strength at 2100 K. Higher Nb/Ta boosts yield strength, Ti/Zr reduce it. Reveals MPEA mechanical anisotropy and strain-rate-dependent disordering, guiding high-performance refractory alloy design.
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All authors Hongyang Liu, Bo Chen, Rong Chen, Dongdong Kang, Jiayu Dai

Materials Science

Controlling the growth of 2D conjugated coordination polymers to induce metallic and spin-dependent transport signatures

Hio-Ieng Un, Jordi Ferrer Orri, Ian E. Jacobs et al. (+5 more)

Understanding growth evolution and thereby implementing precise microstructural tuning of two-dimensional (2D) conjugated coordination polymers (cCPs) is crucial to achieve efficient electronic conduction towards their full potential and to observe materials' intrinsic properties. However, fundamental understanding of how 2D cCPs films grow remains very limited. Here, we use copper-benzenehexathiol (Cu-BHT) cCP as a model system to unravel the growth evolution of layered films in liquid-liquid interfacial synthesis in order to identify strategies to achieve tuning of structure-property relationships. We find that thin films formed at the early stage of growth in 20 minutes facilitate smoother, denser, and horizontally oriented films, and thereby achieve higher electrical conductivity of > 3000 S/cm with a metallic temperature dependence down to 20 K. They also reveal signatures of quantum interference mediated weak antilocalisation and Kondo-like effect in magnetotransport at low temperatures. These phenomena are not observed when long reaction time was employed. Our findings offer a new perspective for the growth of dynamically reversible self-assemblies, that is different from the traditional paradigm of longer reaction time being associated with higher ordering and performance, and offer a platform to study spin-related transport properties of these materials with higher performance for advanced electronic, thermoelectric, and potential spintronic applications.
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All authors Hio-Ieng Un, Jordi Ferrer Orri, Ian E. Jacobs, Naoya Fukui, Hiroshi Nishihara, Caterina Ducati, Samuel D. Stranks, Henning Sirringhaus

Materials Science · Cross-listed from cond-mat.str-el

General linear correction method for DFT+X energy: application to U-M (M=Al, Ga, In) alloys under high pressure

X. L. Pan, H. X. Song, Y. Sun et al. (+6 more)

DFT+X methods, such as DFT+U and DFT+DMFT, are important supplements to standard density functional theory when strong on-site Coulomb interactions are present. However, the involvement of external parameters in the underlying model Hamiltonian introduces intrinsic ambiguity when comparing the total energies obtained with different model parameters. This renders DFT+X approaches semi-empirical and severely hinders their capability to describe phase ordering and phase stability, especially when reliable experimental benchmarks are unavailable, such as under high pressure. In this work, we resolve this longstanding problem by proposing a general linear correction method that eliminates the ambiguous energy contributions introduced by the model Hamiltonian in DFT+X approaches, thereby enabling direct comparison of their energies calculated with different interaction parameters. The method is demonstrated and validated within the framework of DFT+U, an important member of the DFT+X family. It is then applied to important nuclear materials of uranium-based binaries U-M (M=Al, Ga, In) alloys. With this approach, we resolve the long-standing discrepancy between theoretical predictions and experimental observations of phase stability with unprecedented accuracy, and predict several previously unknown stable intermetallic compounds under high pressure. The broad applicability of the method is further confirmed by accurate predictions of formation enthalpies for diverse systems, including Np-Al, U-Si, and Cu-O binaries, the ternary MnSnAu compound, and oxygen adsorption on the Cu(111) surface. This work establishes linear-corrected DFT+U as a fully first-principles approach and validates the linear correction method as a robust and general scheme that can be readily extended to other DFT+X methods.
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All authors X. L. Pan, H. X. Song, Y. Sun, F. C. Wu, H. Wang, Y. F. Wang, Y. Chen, X. R. Chen, Hua Y. Geng

Materials Science

Origin of anomalous p-type conductivity in monolayer Fe-doped MoS2

Xiangning Quan, Xiaoqiu Yuan, Junwei Zhang et al. (+13 more)

Substitutional doping effectively modulates carrier polarity of semiconducting two-dimensional (2D) transition metal dichalcogenides (TMDs) like MoS2. Although Fe doping typically induces n-type conductivity in monolayer MoS2, anomalous p-type behavior has also been experimentally reported, the origin of which remains unresolved. Here, we prove that this anomalous p-type conductivity originates from defect associates formed through interactions between Fe dopants and S atoms, which consists of three Fe substituting Mo (FeMo) point defects arranged into an equilateral triangle with a central S atom, denoted as 3FeMo-S associate. Its p-type effect is directly verified through scanning tunneling microscopy/scanning tunneling spectroscopy (STM/STS) measurement, in sharp contrast to the n-type behavior induced by isolated FeMo point defects, and the conclusion is further supported by electrical transport measurements and first-principles calculations. Similar 3FeW-S associates and their p-type doping effect are also identified in monolayer Fe-doped WS2. This work resolves a longstanding controversy and highlights the critical role of defect associates in modulating properties of 2D TMDs.
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All authors Xiangning Quan, Xiaoqiu Yuan, Junwei Zhang, Xuebing Peng, Helin Mei, Cheng Yan, Hong Zhang, Hongli Li, Daqiang Gao, Yongjian Wang, Mingsu Si, Lili Zhang, Anmin Zhang, Zongyuan Zhang, Lei Shan, Yong Peng

Materials Science

All-electron Quasiparticle Self-consistent GW for Molecules and Periodic Systems within the Numerical Atomic Orbital Framework

Bohan Jia, Min-Ye Zhang, Ziqing Guan et al. (+2 more)

We report an all-electron implementation of the quasiparticle self-consistent GW (QSGW) method for molecular and periodic systems within the framework of numerical atomic orbitals (NAOs), as implemented in the LibRPA software package. Our implementation is based on the space-time formalism, combined with the localized resolution-of-identity approximation to treat two-electron quantities. We found that analytical continuation of the self-energy matrix, in combination with the “Mode B" QSGW scheme, can yield stable self-consistent quasiparticle energy spectra. Systematic benchmark calculations on molecules and crystalline solids (including typical semiconductors and wide-gap insulators) demonstrate that our NAO-based QSGW scheme yields molecular ionization potentials and quasiparticle band gaps for periodic solids that are consistent with reference results from established implementations. Our work opens the way for large-scale QSGW calculations, taking advantage of the NAO-based low-scaling algorithm previously developed for the G0W0 method.
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All authors Bohan Jia, Min-Ye Zhang, Ziqing Guan, Huanjing Gong, Xinguo Ren

Materials Science

Sliding Ferroelectricity Induced and Switched Altermagnetism in GaSe-VPSe3-GaSe Sandwiched Heterostructure with Strong Magnetoelectric Effect

Pengqiang Dong, Hanbo Sun, Chao Wu et al. (+1 more)

Magnetoelectric coupling is vital for exploring fundamental science and driving the development of high-density memory and energy-efficient spintronic devices. Altermagnets, which merge the benefits of ferromagnets and antiferromagnets, pave the way for unprecedented magnetoelectric coupling effects. However, the spin splitting in altermagnets is robustly protected by spin space group symmetry, posing a significant challenge for external manipulation. Here, we propose to utilize the coupling between the layer degree of freedom and the altermagnet to achieve an altermagnetic multiferroic with strong magnetoelectric coupling. In the GaSe-VPSe3-GaSe sandwiched structure, the magnetic order can be switched between altermagnetic and conventional antiferromagnetic by controllably breaking and restoring the combined spatial inversion and time-reversal symmetry using sliding ferroelectricity. Moreover, our systematic investigation of all pathways revealed that the transition from a ferroelectric CB stacking, through an antiferroelectric CC stacking, to a ferroelectric BC stacking is the most favorable, with an energy barrier of only 50.13 meV/f.u.. More importantly, we reveal that the microscopic mechanism of the magnetic phase transition stems from the interlayer covalent bonding of Se-Se or Se-P atomic pairs at the interface. Our findings unveil a new form of magnetoelectric coupling and lay the groundwork for designing miniature information processing and multiferroic memory devices based on altermagnetism.
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All authors Pengqiang Dong, Hanbo Sun, Chao Wu, Ping Li

Materials Science · Cross-listed from cond-mat.supr-con

Pressure-tuned double-dome superconductivity in KZnBi with honeycomb lattice

Cuiying Pei, Hongjoo Ha, Sen Shao et al. (+8 more)

Materials with honeycomb lattice structures exhibit unique electronic properties arising from their distinctive atomic arrangements. Their weakly coupled nature facilitates modulation by external stimuli, which leads to a diverse range of physical phenomena, particularly superconductivity. Here, we report the discovery of a pressure-induced M-shaped double-dome superconducting phase in KZnBi with honeycomb lattice. Under applied pressure, the superconducting transition temperature Tc increases sharply and reaches a maximum value of 7 K at approximately 2.5 GPa. Following a structural phase transition from the ambient-pressure P63/mmc phase to the high-pressure Pnma phase, Tc gradually decreases. Further compression induces an electronic transition near 7 GPa, accompanied by an unexpected reentrant superconducting phase with a higher Tc of 8 K. Our theoretical calculations indicate that KZnBi undergoes a transition from a Dirac band structure to a strong topological semimetal state following the structural phase transition. These findings establish KZnBi as an ideal platform for investigating the diverse structural manifestations and intrinsic phenomena of the honeycomb lattice, demonstrating the fundamental importance of honeycomb structures in advancing superconductivity research.
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All authors Cuiying Pei, Hongjoo Ha, Sen Shao, Shihao Zhu, Qi Wang, Juefei Wu, Yanchao Wang, Yulin Chen, Yanming Ma, Sung Wng Kim, Yanpeng Qi

Materials Science

Van der Waals Antiferromagnets: From Early Discoveries to Future Directions in the 2D Limit

Rahul Kumar and Je-Geun Park

The emergence of a long-range magnetic order in the atomically thin, two-dimensional (2D) limit has long remained a fundamental question in condensed matter physics. The advent of exfoliable van der Waals (vdW) materials, particularly transition-metal phosphorus trisulfides (T MPS3; T M = Fe, Ni, and Mn), provided the first experimental access to this regime and established a foundational platform for investigating 2D magnetism. The 2016 experimental demonstrations of intrinsic magnetism in monolayer FePS3 provided a platform to test key aspects of 2D Ising criticality in the true 2D limit. It was followed by a rapid growth resulting in a wealth of emergent phenomena arising from the interplay of low-dimensional magnetism and quantum materials. We begin this review with the historical development of vdW antiferromagnets and highlight the key physical insights gained over the past decade. We finish with emerging opportunities in which vdW antiferromagnets can serve as versatile platforms for exploring low-dimensional magnetism and its interplay with other quantum degrees of freedom.
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Materials Science

Kinetics of Stacking Order Evolution During Heterogeneous Ice Formation

Xudan Huang, Zifeng Yuan, Chon-Hei Lo et al. (+11 more)

The selection of stacking order in a broad range of close-packed polymorphic materials remains a challenging enigma. Using in situ cryogenic transmission electron microscopy, we uncover the atomistic mechanisms governing the vapour deposition growth of ice. We find that the heterogeneous ice nucleation and growth undergoes recrystallization accompanied by bifurcation, reflecting a coherent epitaxial transition from a cubic-ice embryonic core to hexagonal-ice prismatic dendrites, with intermediate stacking-disordered layers serving as a dynamic fluctuating bridge. Supported by molecular dynamics simulations, these phenomena are attributed to a surface-constrained, symmetry-breaking crystallization preference aligned with the principle of minimizing free energy. Our results highlight the critical role of the combined effects of surface and symmetry in shaping ice crystallization, providing fresh insights into crystal growth mechanisms and guiding principles for the design of advanced materials.
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All authors Xudan Huang, Zifeng Yuan, Chon-Hei Lo, Huacong Sun, Lei Liao, Hongbo Han, Wenxi Li, Wenlong Wang, Zhi Xu, Lei Liu, Xuedong Bai, Limei Xu, Enge Wang, Lifen Wang