CMP Journal 2025-05-08
Statistics
Physical Review Letters: 11
Physical Review X: 2
arXiv: 59
Physical Review Letters
Unitary Designs of Symmetric Local Random Circuits
Research article | Quantum circuits | 2025-05-07 06:00 EDT
Yosuke Mitsuhashi, Ryotaro Suzuki, Tomohiro Soejima, and Nobuyuki Yoshioka
We have established the method of characterizing the unitary design generated by a symmetric local random circuit. Concretely, we have shown that the necessary and sufficient condition for the circuit asymptotically forming a $t$-design is given by simple integer optimization for general symmetry and locality. By using the result, we explicitly give the maximal order of unitary design under the ${\mathbb{Z}}_{2}$, U(1), and SU(2) symmetries for general locality. This work reveals the relation between the fundamental notions of symmetry and locality in terms of randomness.
Phys. Rev. Lett. 134, 180404 (2025)
Quantum circuits, Quantum control, Quantum information theory
Quantum Dynamic Programming
Quantum algorithms & computation | 2025-05-07 06:00 EDT
Jeongrak Son, Marek Gluza, Ryuji Takagi, and Nelly H. Y. Ng
We introduce a quantum extension of dynamic programming, a fundamental computational method that efficiently solves recursive problems using memory. Our innovation lies in showing how to coherently generate recursion step unitaries by using memorized intermediate quantum states. Quantum dynamic programming achieves an exponential reduction in circuit depth for a broad class of fixed-point quantum recursions, though this comes at the cost of increased circuit width. Interestingly, the trade-off becomes more favorable when the initial state is pure. By hybridizing our approach with a conventional memoryless one, we can flexibly balance circuit depth and width to optimize performance on quantum devices with fixed hardware constraints. Finally, we showcase applications of quantum dynamic programming to several quantum recursions, including a variant of Grover’s search, quantum imaginary-time evolution, and a new protocol for obliviously preparing a quantum state in its Schmidt basis.
Phys. Rev. Lett. 134, 180602 (2025)
Quantum algorithms & computation, Quantum information processing
Domain-Wall Skyrmion Phase in Dense QCD at Strong Magnetic Fields Using Leading-Order Chiral Perturbation Theory
Research article | QCD phase transitions | 2025-05-07 06:00 EDT
Minoru Eto, Kentaro Nishimura, and Muneto Nitta
Low-energy dynamics of QCD can be described by pion degrees of freedom in terms of the chiral perturbation theory. A chiral soliton lattice, an array of solitons, is the ground state due to the chiral anomaly in the presence of a magnetic field larger than a certain critical value at finite density. Here, we show in a model-independent and fully analytic manner (at the leading order of the chiral perturbation theory) that the chiral soliton lattice phase transits to a ‘’domain-wall skyrmion phase’’ when the chemical potential is larger than the critical value ${\mu }{\mathrm{c}}=16\pi {f}{\pi }^{2}/3{m}{\pi }\sim 1.03\text{ }\text{ }\mathrm{GeV}$ with the pion’s decay constant ${f}{\pi }$ and mass ${m}_{\pi }$, which can be regarded as the nuclear saturation density. There spontaneously appear stable two-dimensional skyrmions or lumps on a soliton surface, which can be viewed as three-dimensional skyrmions carrying even baryon numbers from the bulk. They behave as superconducting rings with persistent currents due to a charged pion condensation. This phase is in scope of future heavy-ion collider experiments.
Phys. Rev. Lett. 134, 181902 (2025)
QCD phase transitions, Quantum chromodynamics, Topological defects
Charge Radii of Neutron-Rich Scandium Isotopes and the Seniority Symmetry in the $0{f}_{7/2}$ Shell
Research article | Nuclear charge distribution | 2025-05-07 06:00 EDT
S. W. Bai et al.
Nuclear charge radii of neutron-rich $^{47–49}\mathrm{Sc}$ isotopes were measured using collinear laser spectroscopy at CERN-ISOLDE. The new data reveal that the charge radii of scandium isotopes exhibit a distinct trend between $N=20$ and $N=28$, with $^{41}\mathrm{Sc}$ and $^{49}\mathrm{Sc}$ isotopes having similar values, mirroring the closeness of the charge radii of $^{40}\mathrm{Ca}$ and $^{48}\mathrm{Ca}$. Theoretical models that successfully interpret the radii of calcium isotopes could not account for the observed behavior in scandium radii, in particular the reduced odd-even staggering. Remarkably, the inclusion of the new $^{49}\mathrm{Sc}$ radius data has unveiled a similar trend in the charge radii of $N=28$ isotones and $Z=20$ isotopes when adding the protons atop the $^{48}\mathrm{Ca}$ core and the neutrons atop the $^{40}\mathrm{Ca}$ core, respectively. We demonstrate that this trend is consistent with the prediction of the seniority model.
Phys. Rev. Lett. 134, 182501 (2025)
Nuclear charge distribution, Nuclear forces, Nuclear many-body theory, Nuclear radii, Nuclear structure & decays, Radioactive beams
Thermodynamics of Spin-Imbalanced Fermi Gases with $\mathrm{S}\mathrm{U}(N)$-Symmetric Interaction
Research article | Fermi gases | 2025-05-07 06:00 EDT
Chengdong He, Xin-Yuan Gao, Ka Kwan Pak, Yu-Jun Liu, Peng Ren, Mengbo Guo, Entong Zhao, Yangqian Yan, and Gyu-Boong Jo
Thermodynamics of degenerate Fermi gases has been extensively studied through various aspects such as Pauli blocking effects, collective modes, BCS superfluidity, and more. Despite this, multicomponent fermions with imbalanced spin configurations remain largely unexplored, particularly beyond the two-component scenario. In this Letter, we generalize the thermodynamic study of $\mathrm{SU}(N)$ fermions to spin-imbalanced configurations based on density fluctuations. Theoretically, we provide closed-form expressions of density fluctuation across all temperature ranges for general spin population setups. Experimentally, after calibrating the measurements with deeply degenerate $^{173}\mathrm{Yb}$ Fermi gases under spin-balanced configurations ($N\le 6$), we examine the density fluctuations in spin-imbalanced systems. Specifically, we investigate two-species and four-species configurations to validate our theoretical predictions. Our analysis indicates that interaction enhancement effects can be significant even in highly spin-imbalanced systems. Finally, as an application, we use this approach to examine the decoherence process. Our Letter provides a deeper understanding of the thermodynamic features of spin-imbalanced multicomponent Fermi gases and opens new avenues for exploring complex quantum many-body systems.
Phys. Rev. Lett. 134, 183406 (2025)
Fermi gases, Ultracold gases, Fermi liquid theory, SU(N) symmetries
$X$-Point Target Radiator Regime in Tokamak Divertor Plasmas
Research article | Magnetic confinement fusion | 2025-05-07 06:00 EDT
K. Lee, C. Theiler, M. Carpita, O. Février, A. Perek, M. Zurita, D. Brida, R. Ducker, G. Durr-Legoupil-Nicoud, B. P. Duval, S. Gorno, D. Hamm, D. S. Oliveira, F. Pastore, M. Pedrini, H. Reimerdes, L. Simons, E. Tonello, K. Verhaegh, Y. Wang, and C. Wüthrich (the TCV Team and the EUROfusion Tokamak Exploitation Team)
Fusion reactor experiments in Switzerland have demonstrated a new way to remove unwanted heat from a magnetically confined plasma.
Phys. Rev. Lett. 134, 185102 (2025)
Magnetic confinement fusion, Nuclear fusion, Plasma fusion, Plasma-wall interactions, Fusion reactors, Magnetically confined plasmas, Tokamaks
Scattering Theory of Thermal and Bipolar Thermoelectric Diodes
Research article | Quantum interference effects | 2025-05-07 06:00 EDT
José Balduque and Rafael Sánchez
We investigate the minimal requirements that induce a nonreciprocal response to temperature differences in a mesoscopic electronic conductor. We identify two distinct mechanisms involved in electron-electron interactions, namely inelastic scattering and screening, that locally affect the internal properties of the device, leading to thermal and thermoelectric rectification effects in the absence of inversion symmetry. We propose resonant tunneling samples to efficiently exploit these effects, and find configurations acting as bipolar thermoelectric diodes whose current flows in the same direction irrespective of the sign of the temperature difference, a case of antireciprocity.
Phys. Rev. Lett. 134, 186301 (2025)
Quantum interference effects, Quantum transport, Thermoelectric effects, Diodes, Heat engines, Nanostructures, Thermoelectrics, Landauer formula, S-matrix method in transport
Fractals in the Critical Attractor of the Classical Sandpile Model
Research article | Fractional dimension | 2025-05-07 06:00 EDT
Marcus Engsig and Kim Sneppen
The classical sandpile model for self-organized criticality is analyzed with deterministic perturbations. This allows us to explore underlying long-range correlations in the critical attractor and quantify these as the fractal dimension of excitable sites and the fractal dimension of avalanche termination sites. The fractal of highly excitable sites, characterized by a dimension of 1.3, is associated with the avalanches responsible for most of the relaxations in the system. Furthermore, the fractal dimension of these highly excitable sites suggests a scaling exponent for avalanche sizes of 1.26, consistent with earlier literature.
Phys. Rev. Lett. 134, 187201 (2025)
Fractional dimension, Self-organized criticality
Dynamics of Critical Cascades in Interdependent Networks
Research article | Stochastic processes | 2025-05-07 06:00 EDT
Dolev Dilmoney, Bnaya Gross, Shlomo Havlin, and Nadav M. Shnerb
The failure of interdependent networks, as well as similar avalanche phenomena, is driven by cascading failures. At the critical point, the cascade begins as a critical branching process, where each failing node (element) triggers, on average, the failure of one other node. As nodes continue to fail, the network becomes increasingly fragile, and the branching factor grows. If the failure process does not reach extinction during its critical phase, the network undergoes an abrupt collapse. Here, we implement the analogy between this dynamic and birth-death processes to derive new analytical results and significantly optimize numerical calculations. Using this approach, we analyze three key aspects of the dynamics: the probability of collapse, the duration of avalanches, and the length of the cascading plateau phase preceding a collapse. This analysis quantifies how the system size and the intensity of the initial triggering event influence these characteristics.
Phys. Rev. Lett. 134, 187401 (2025)
Stochastic processes, Interconnected & interdependent networks, First passage problems
Shape of a Membrane on a Liquid Interface with Arbitrary Curvatures
Research article | Capillary interactions | 2025-05-07 06:00 EDT
Zachariah S. Schrecengost, Seif Hejazine, Jordan V. Barrett, Vincent Démery, and Joseph D. Paulsen
We study the deformation of a liquid interface with arbitrary principal curvatures by a flat circular sheet. Working first at small slopes, we determine the shape of the sheet analytically in the membrane limit, where the sheet is inextensible yet free to bend and compress. We find that the sheet takes a cylindrical shape on interfaces with negative Gaussian curvature. On interfaces with positive Gaussian curvature, an inner region still adopts a cylindrical shape while the outer region is under azimuthal compression. Numerical energy minimization confirms our predictions and shows that this behavior holds for finite slopes. Experiments on a thin polystyrene film at an anisotropic air-water interface show consistent behaviors.
Phys. Rev. Lett. 134, 188202 (2025)
Capillary interactions, Elastic deformation, Surface tension effects, Wrinkling, Geometry
Active-Hydraulic Flows Solve the Six-Vertex Model (and Vice Versa)
Research article | Collective behavior | 2025-05-07 06:00 EDT
Camille Jorge and Denis Bartolo
Researchers demonstrate an active-fluid system whose behaviors map directly to predictions of the six-vertex model–an exactly solvable model that was originally developed to explain the behavior of ice.
Phys. Rev. Lett. 134, 188302 (2025)
Collective behavior, Flocking, Living matter & active matter, Lithography, Particle image velocimetry, Percolation theory, Potts model
Physical Review X
Symmetry-Dependent Dielectric Screening of Optical Phonons in Monolayer Graphene
Research article | Electronic structure | 2025-05-07 06:00 EDT
Loïc Moczko, Sven Reichardt, Aditya Singh, Xin Zhang, Elise Jouaiti, Luis E. Parra López, Joanna L. P. Wolff, Aditi Raman Moghe, Etienne Lorchat, Rajendra Singh, Kenji Watanabe, Takashi Taniguchi, Hicham Majjad, Michelangelo Romeo, Arnaud Gloppe, Ludger Wirtz, and Stéphane Berciaud
Symmetry governs the sensitivity of optical phonons in graphene to the local environment, with implications for van der Waals engineering and quantum sensing.
Phys. Rev. X 15, 021043 (2025)
Electronic structure, Optical phonons, Phonons, Inelastic light scattering, Photoluminescence, Quantum field theory (low energy), Sample preparation, Symmetries in condensed matter
Multiscale Field Theory for Network Flows
Research article | Jamming | 2025-05-07 06:00 EDT
Guram Mikaberidze, Oriol Artime, Albert Díaz-Guilera, and Raissa M. D’Souza
A new theoretical framework reveals universal principles governing network flows, predicting a threshold where flow becomes unsustainable and uncovering how dissipation can enhance performance in certain systems.
Phys. Rev. X 15, 021044 (2025)
Jamming, Network flow, Traffic
arXiv
X-ray induced quenching of the 229Th clock isomer in CaF2
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-08 20:00 EDT
Ming Guan, Michael Bartokos, Kjeld Beeks, Hiroyuki Fujimoto, Yuta Fukunaga, Hiromitsu Haba, Takahiro Hiraki, Yoshitaka Kasamatsu, Shinji Kitao, Adrian Leitner, Takahiko Masuda, Nobumoto Nagasawa, Koichi Okai, Ryoichiro Ogake, Martin Pimon, Martin Pressler, Noboru Sasao, Fabian Schaden, Thorsten Schumm, Makoto Seto, Yudai Shigekawa, Kotaro Shimizu, Tomas Sikorsky, Kenji Tamasaku, Sayuri Takatori, Tsukasa Watanabe, Atsushi Yamaguchi, Yoshitaka Yoda, Akihiro Yoshimi, Koji Yoshimura
Thorium-229 has the lowest nuclear-excited state (an isomer state) at approximately 8.356 eV, making it excitable with tabletop vacuum-ultraviolet lasers. Despite the recent success of laser excitation, the isomer quenching inside the solid-state environment remains unresolved. In this letter, we present experiments investigating X-ray-induced isomer quenching in the CaF$ _2$ host, focusing on the effects of X-ray flux and temperature on the lifetime and yield of the isomer state. Our studies reveal a correlation between isomer production, isomer lifetime during irradiation, and post-irradiation afterglow of the target crystal across different temperatures, highlighting a strong relationship between isomer quenching and color-center dynamics. We developed a model to interpret the isomer quenching and the crystal’s luminescence.
Materials Science (cond-mat.mtrl-sci), Nuclear Experiment (nucl-ex)
8 pages, 5 figures, 18 equations
Geometry dependence of the thermal Hall effect in chiral spin liquids
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-08 20:00 EDT
Recent thermal-transport experiments on the Kitaev magnet $ \alpha$ -RuCl$ _3$ highlight the challenge in identifying chiral quantum spin liquids through their quantized thermal Hall effect. Here, we propose that variations in the underlying sample geometry – for example, the introduction of appropriate constrictions – reveal unique aspects of the thermal Hall effect and can be used to determine its origin. By studying standard phenomenological heat-transport equations based on minimal assumptions, we show that, whereas a conventional thermal Hall effect due to, e.g., phonons or magnons is completely geometry independent, a thermal Hall effect originating from a chiral fermion edge mode is significantly enhanced by constrictions at low temperatures. This unique geometry-dependent signature provides a practical approach for identifying chiral spin liquids in candidate materials like $ \alpha$ -RuCl$ _3$ using currently available thermal-transport experiments.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
6+2 pages, 2 figures
Transdimensional anomalous Hall effect in rhombohedral thin graphite
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-08 20:00 EDT
Qingxin Li, Hua Fan, Min Li, Yinghai Xu, Junwei Song, Kenji Watanabe, Takashi Taniguchi, Hua Jiang, X. C. Xie, James Hone, Cory Dean, Yue Zhao, Jianpeng Liu, Lei Wang
Anomalous Hall effect (AHE), occurring in materials with broken time-reversal symmetry, epitomizes the intricate interplay between magnetic order and orbital motions of electrons[1-4]. In two dimensional (2D) systems, AHE is always coupled with out-of-plane orbital magnetization associated in-plane chiral orbital motions. In three dimensional (3D) systems, carriers can tunnel or scatter along the third dimension within the vertical mean free path lz. When sample thickness far exceeds lz, scattering disrupts coherent out-of-plane motion, making 3D AHE effectively a thickness-averaged 2D counterpart[4]- still governed by out-of-plane orbital magnetization arising from in-plane orbital motions. Here, we explore an uncharted regime where the sample thickness is much larger than the atomic layer thickness yet smaller than or comparable to lz. In such “transdimensional” regime, carriers can sustain coherent orbital motions both within and out of the 2D plane, leading to a fundamentally new type of AHE that couples both out-of-plane and in-plane orbital magnetizations. We report the first observation of such phenomenon- transdimensional AHE (TDAHE)- in electrostatically gated rhombohedral ennealayer graphene. This state emerges from a peculiar metallic phase that spontaneously breaks time-reversal, mirror and rotational symmetries driven by electron-electron interactions. Such TDAHE manifests as concurrent out-of-plane and in-plane Hall resistance hysteresis, controlled by external magnetic fields along either direction. Our findings unveils a new class of AHE, opening an unexplored paradigm for correlated and topological physics in transdimensional systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
35pages, 15figures
Spectroscopic evidence of intra-unit-cell charge redistribution in charge-neutral magnetic topological insulator Sb-doped MnBi6Te10
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-08 20:00 EDT
Khanh Duy Nguyen, Gabriele Berruto, Seng Huat Lee, Yunhe Bai, Haoran Lin, Qiang Gao, Zhiqiang Mao, Shuolong Yang
The magnetic topological insulator MnBi$ _{6}$ Te$ _{10}$ has emerged as a promising candidate for realizing the quantum anomalous Hall effect (QAHE), owing to its ability to retain ferromagnetism through precise control of anti-site defects. The next important task for realizing the QAHE is to tune the chemical potential into the energy gap formed by the broken time-reversal symmetry. Here we reveal an intra-unit-cell charge redistribution even when the overall doping suggests a near-charge-neutral condition. By performing time- and angle-resolved photoemission spectroscopy (trARPES) on the optimally 18% Sb-doped MnBi$ _{6}$ Te$ _{10}$ , we observe transient surface photovoltage (SPV) effects on both the MnBi$ _{2}$ Te$ _{4}$ and single-Bi$ _{2}$ Te$ _{3}$ terminations. Furthermore, we observe a time-dependent splitting of the band structure indicating multiple SPV shifts with different magnitudes. This observation suggests that adjacent plateaus with nominally the same terminating layer exhibit a strong intra-unit-cell charge redistribution, resulting in spontaneous electrical polarization. This is consistent with static micro-ARPES measurements revealing significant doping deviations from the charge-neutral configuration. Our findings underscore the challenges of engineering the family of Mn-Bi-Te materials to realize QAHE purely through chemical doping. Achieving the desired topological quantum phase requires both a uniform carrier doping and a ferromagnetic ground state. Furthermore, the light-induced polarization within each unit cell of ferromagnetic Mn(Bi$ _{0.82}$ Sb$ _{0.18}$ )$ _{6}$ Te$ _{10}$ may open new possibilities for optoelectronic and spintronics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
11 pages, 4 figures
Direct evidence of light-induced phase-fluctuations in cuprates via time-resolved ARPES
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-08 20:00 EDT
D. Armanno, F. Goto, J.-M. Parent, S. Lapointe, A. Longa, R. D. Zhong, J. Schneeloch, G.D. Gu, G. Jargot, H. Ibrahim, F. Legare, B.J. Siwick, N. Gauthier, F. Boschini
Phase fluctuations are widely accepted to play a primary role in the quench of the long-range superconducting order in cuprates. However, an experimental probe capable of unambiguously assessing their impact on the superconducting order parameter with momentum and time resolutions is still lacking. Here, we performed a high-resolution time- and angle-resolved photoemission study of optimally-doped Bi$ _2$ Sr$ _2$ CaCu$ _2$ O$ _{8+\delta}$ and demonstrated a new experimental strategy to directly probe light-induced changes in the order parameter’s phase with momentum resolution. To do this, we tracked the ultrafast response of a phase-sensitive hybridization gap that appears at the crossing between two bands with opposite superconducting gap signs. Supported by theoretical modeling, we established phase fluctuations as the dominant factor defining the non-thermal response of the unconventional superconducting phase in cuprates.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
Directional Thermal Emission Across Both Polarizations in Planar Photonic Architectures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-08 20:00 EDT
David E. Abraham, Daniel Cui, Baolai Liang, Jae S. Hwang, Parthiban Santhanam, Linus Kim, Rayen Lin, Aaswath P. Raman
Directional and spectral control of thermal emission is essential for applications in energy conversion, imaging, and sensing. Existing planar, lithography-free epsilon-near-zero (ENZ) films only support transverse-magnetic (TM) control of thermal emission via the Berreman mode and cannot address transverse-electric (TE) waves due to the absence of natural optical magnetism over optical and infrared wavelengths Here, we introduce a hyperbolic metamaterial comprising alternating layers of degenerately-doped and intrinsic InAs that exhibits an epsilon-and-mu-near-zero (EMNZ) response, enabling dual-polarized, directionally and spectrally selective thermal emission. We first theoretically demonstrate that a mu-near-zero (MNZ) film on a perfect magnetic conductor supports a magnetic Berreman mode, absorbing TE-polarized radiation in analogy to the conventional Berreman mode supported in TM polarization. Using genetic and gradient-descent optimization, we design a dual-polarized emitter with independently tunable spectral peaks and emission angles. Parameter retrieval via homogenization confirms simultaneous EMNZ points at the target wavelengths and angles. Finally, experimental measurement of a sample fabricated via molecular beam epitaxy exhibits high absorptivity peaks for both polarizations in close agreement with simulations. This work realizes lithography-free, dual-polarized, spectrally and directionally selective emitters, offering a versatile platform for advanced infrared thermal management and device integration.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Large critical current density Josephson $π$ junctions with PdNi barriers
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-08 20:00 EDT
Arjun Sapkota, Robert M. Klaes, Reza Loloee, Norman O. Birge, Nathan Satchell
We report large critical current densities in $ \text{Nb} / \text{Pd}{89}\text{Ni}{11} / \text{Nb}$ Josephson junctions at thicknesses of $ \text{Pd}{89}\text{Ni}{11}$ close to where the first $ \pi$ -state is expected. We observe possible oscillations in the critical current density with the thickness of the $ \text{Pd}{89}\text{Ni}{11}$ layer that are consistent with a $ 0-\pi$ transition. From temperature-dependent measurements, we find a large critical current density through our $ \text{Pd}{89}\text{Ni}{11}$ barriers, exceeding 550 $ \text{kA/cm}^2$ at 2 K in zero applied magnetic field, for a barrier thickness of 9.4 nm. From measurements of magnetization on sheet film samples, we confirm that the $ \text{Pd}{89}\text{Ni}{11}$ layer exhibits perpendicular magnetic anisotropy. Both the large critical current density and the perpendicular magnetic anisotropy are beneficial for proposed applications of $ \pi$ -junctions in superconducting digital logic and qubits.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
6 pages, 5 figures
Microscopic theory of phonon polaritons and long wavelength dielectric response
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-08 20:00 EDT
We present a first-principles approach for calculating phonon-polariton dispersion relations. In this approach, phonon-photon interaction is described by quantization of a Hamiltonian that describes harmonic lattice vibrations coupled with the electromagnetic field inside the material. All Hamiltonian parameters are obtained from first-principles calculations, with diagonalization leading to non-interacting polariton quasiparticles. This method naturally includes retardation effects and resolves non-analytical behavior and ambiguities in phonon frequencies at the Brillouin zone center, especially in non-cubic and optically anisotropic materials. Furthermore, by incorporating higher-order terms in the Hamiltonian, we also account for quasiparticle interactions and spectral broadening. Specifically, we show how anharmonic effects in phonon polaritons lead to a dielectric response that challenges traditional models. The accuracy and consequences of the approach are demonstrated on GaP and GaN as harmonic test systems and PbTe and $ \beta$ -Ga$ _2$ O$ _3$ as anharmonic test systems.
Materials Science (cond-mat.mtrl-sci)
The study of Ag(Cu) center creation in quartz crystals by thermal annealing at 1200C in oxygen atmosphere from metallic Ag and Au
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-08 20:00 EDT
Anatoly Trukhin, Madara Leimane
The study of silver or copper center creation in quartz crystals by thermal annealing at 1200C in oxygen atmosphere from metallic silver and gold. Previously, the effect of treatment in oxygen atmosphere at high temperatures on copper luminescence centers in quartz was discovered. In this work, we investigated the effect of such treatment on silver centers in quartz, studied previously. Also, a series of non-activated crystalline quartz samples were thermally annealed at 1200C in an oxygen atmosphere together with metallic silver. An attempt was made to introduce gold into quartz by such treatment in oxygen. Both high-purity gold and containing parasitic impurities of silver and copper were used. In the latter case, we obtained silver and copper luminescence centers but were unable to identify the luminescence of centers associated with Au.
Materials Science (cond-mat.mtrl-sci)
research was presented at conference “LUMDETR-2024” 9 pages, 8 figures
Electron Model on Truchet Tiling: Extended-to-Localized Transitions, Mobility Edge, and Asymmetric Spectrum
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-05-08 20:00 EDT
Motivated by recent advances in the realization of Truchet-tiling structures in molecular networks and metal-organic frameworks, we investigate the wave localization issue in this kind of structure. We introduce an electron model based on random Truchet tilings-square lattices with randomly oriented diagonal links-and uncover a rich interplay between spectral and localization phenomena. By varying the strength of diagonal couplings, we demonstrate successive transitions from an extended phase, through a regime with a mobility edge, to a fully localized phase. The energy-resolved fractal dimension analysis captures the emergence and disappearance of mobility edges, while an anomalous shift and asymmetry in the van Hove singularity are identified as key signatures of the underlying disordered Truchet-tiling structure. Our findings position Truchet-tiled electron systems as a versatile platform for engineering disorder-driven localization and interaction effects in amorphous quantum materials and photonic architectures.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
9 pages, 5 figures
Observation of Order and Disorder in Solid-Electrolyte Interphases of Lithium-Metal Anodes
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-08 20:00 EDT
Hyeongjun Koh, Eric Detsi, Eric A. Stach
Battery interfaces critically influence lithium-metal battery performance through their role in ion diffusion and dendrite formation. However, structural characterization of these interfaces has remained challenging due to limitations in high-resolution methods and artifacts from electron irradiation. Using cryogenic conditions for both specimen preparation and scanning electron nanobeam diffraction, we can determine the structural organization at the interface between the vitrified electrolyte and adjacent layers. We identified two distinct interface types: one showing short-range order adjacent to lithium metal, and another displaying a mixed structure of short-range ordering and defective lithium fluoride nanoscale crystallites at a copper collector. Notably, short-range order appeared exclusively in electrolytes demonstrating high reversibility. Our results establish that solid-electrolyte-interphase structure directly influences lithium deposition morphology and battery performance. This methodology opens new possibilities for high-resolution characterization of interfaces in energy storage materials, advancing our understanding of their critical structural properties.
Materials Science (cond-mat.mtrl-sci), Atomic Physics (physics.atom-ph)
Anomalous grain dynamics and grain locomotion of odd crystals
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-08 20:00 EDT
Zhi-Feng Huang, Michael te Vrugt, Raphael Wittkowski, Hartmut Löwen
Crystalline or polycrystalline systems governed by odd elastic responses are known to exhibit complex dynamical behaviors involving self-propelled dynamics of topological defects with spontaneous self-rotation of chiral crystallites. Unveiling and controlling the underlying mechanisms require studies across multiple scales. We develop such a type of approach that bridges between microscopic and mesoscopic scales, in the form of a phase field crystal model incorporating transverse interactions. This continuum density field theory features two-dimensional parity symmetry breaking and odd elasticity, and generates a variety of interesting phenomena that agree well with recent experiments and particle-based simulations of active and living chiral crystals, including self-rotating crystallites, dislocation self-propulsion and proliferation, and fragmentation in polycrystals. We identify a distinct type of surface cusp instability induced by self-generated surface odd stress that results in self-fission of single-crystalline grains. This mechanism is pivotal for the occurrence of various anomalous grain dynamics for odd crystals, particularly the predictions of a transition from normal to reverse Ostwald ripening for self-rotating odd grains, and a transition from grain coarsening to grain self-fragmentation in the dynamical polycrystalline state with an increase of transverse interaction strength. We also demonstrate that the single-grain dynamics can be maneuvered through the variation of interparticle transverse interactions. This allows to steer the desired pathway of grain locomotion and to control the transition between grain self-rotation, self-rolling, and self-translation. Our results provide insights for the design and control of structural and dynamical properties of active odd elastic materials.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech), Adaptation and Self-Organizing Systems (nlin.AO)
13 pages, 5 figures, and 10 pages Supporting Information
Electron-Phonon Coupling in Correlated Metals: A Dynamical Mean-Field Theory Study
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-08 20:00 EDT
David J. Abramovitch, Jennifer Coulter, Sophie Beck, Andrew Millis
Strong electron-electron interactions are known to significantly modify the electron-phonon coupling relative to the predictions of density functional theory, but this effect is challenging to calculate with realistic theories of strongly correlated materials. Here we define and calculate a version of the EPC applicable beyond band theory by combining first principles density functional theory plus dynamical mean-field theory with finite difference phonon perturbations, presenting results for several representative phonon modes in two materials of interest. In the three-orbital correlated metal SrVO$ 3$ , we find that intra-V-$ t{2g}$ band correlation significantly increases the coupling of these electrons to a Jahn-Teller phonon mode that splits the degenerate orbital energies, while slightly reducing the coupling associated with a breathing phonon that couples to the charge on each V atom. In the infinite layer cuprate CaCuO$ 2$ , we find that local correlation within the $ d{x^2-y^2}$ orbital derived band has a modest effect on coupling of near-Fermi surface electrons to optical breathing modes. In both cases, the interaction correction to the electron-phonon coupling predicted by dynamical mean-field theory has a significant dependence on the electronic frequency, arising from a lattice-distortion dependence of the correlated electron dynamics, showing the inadequacy of the simple picture in which correlations change static local susceptibilities. We also show that the electron-phonon scattering and phonon lifetimes associated with these phonon modes are modified by the electronic correlation. Our findings shed light on the material- and mode-specific role of dynamical electronic correlation in electron-phonon coupling and highlight the importance of developing efficient computational methods for treating electron-phonon coupling in correlated materials.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
16 pages, 7 figures
Sound Attenuation in Glasses
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-05-08 20:00 EDT
Grzegorz Szamel, Elijah Flenner
Comprehending sound damping is integral to understanding the anomalous low temperature properties of glasses. Despite decades of studies, the underlying mechanism of sound damping in glasses is still debated. In this perspective we review recent work on sound damping in amorphous solids. We focus on the role of defects, heterogeneous elasticity, and damping in model amorphous solids without defects. We review our definition of damping defects and show that they strongly influence sound damping. However, we also find another contribution to sound damping that cannot be attributed to damping defects. We confirm an earlier result of Kapteijns et al. [G. Kapteijns et al., J. Chem. Phys. 154, 081101 (2021)] that heterogeneous elasticity theory predicts relative changes of sound damping in model two-dimensional glasses if the configuration-to-configuration elastic constants fluctuations are used to quantify the heterogeneity. We extend this finding to similar three-dimensional glasses. We end by discussing the Euclidean Random Matrix model, which exhibits Rayleigh scaling of sound damping, but does not have quasi-localized excitations, and thus probably does not have sound damping defects. We propose that the mechanisms behind sound damping can be more fully understood by approaching the problem from two directions, one where the strong influence of defects is studied and another where sound damping is studied in defect free albeit disordered materials.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Soft Condensed Matter (cond-mat.soft)
9 pages, 4 figures
Investigation of Low Frequency Noise in CryoCMOS devices through Statistical Single Defect Spectroscopy
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-08 20:00 EDT
Edoardo Catapano, Anirudh Varanasi, Philippe Roussel, Robin Degraeve, Yusuke Higashi, Ruben Asanovski, Ben Kaczer, Javier Diaz Fortuny, Michael Waltl, Valeri Afanasiev, Kristiaan De Greve, Alexander Grill
High 1/f noise in CryoCMOS devices is a critical parameter to keep under control in the design of complex circuits for low temperatures applications. Current models predict the 1/f noise to scale linearly with temperature, and gate oxide defects are expected to freeze out at cryogenic temperatures. Nevertheless, it has been repeatedly observed that 1/f noise deviates from the predicted behaviour and that gate oxide defects are still active around 4.2 K, producing random telegraph noise. In this paper, we probe single gate oxide defects in 2500 nMOS devices down to 5 K in order to investigate the origin of 1/f noise in CryoCMOS devices. From our results, it is clear that the number of defects active at cryogenic temperatures resulting in random telegraph noise is larger than at 300 K. Threshold voltage shifts due to charged defects are shown to be exponentially distributed, with different modalities across temperatures and biases: from monomodal at 300 K to trimodal below 100 K. The third mode is interpreted in the framework of percolation theory. By fitting these distributions, it is shown that more than 80% of the detected defects belongs to the oxide bulk. Afterwards, starting from the raw data in time domain, we reconstruct the low frequency noise spectra, highlighting the contributions of defects belonging to different branches and, therefore, to different oxide layers. This analysis shows that, although interface traps and large defects associated with the third mode are the main sources of 1/f noise at 5 K, bulk oxide defects still contribute significantly to low-frequency noise at cryogenic temperatures. Finally, we show that defect time constants and step heights are uncorrelated, proving that elastic tunnelling model for charge trapping is not accurate.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph)
Study of the Extended Yard Sale model of wealth distribution on Erdős-Rényi random networks
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-08 20:00 EDT
Nicolás Vazquez Von Bibow, Juan I. Perotti
Excessive wealth concentration can undermine economic and social development. Random Asset Exchange (RAE) models provide valuable tools to investigate this phenomenon. Assuming that economic systems may operate optimally near the critical point of a continuous phase transition, the Extended Yard Sale (EYS) model introduced by Boghosian et al.~[Physica A 476, 15 (2017)] offers a compelling framework. This model captures the interplay between wealth redistribution and accumulation, exhibiting a continuous phase transition marked by a broad wealth distribution at criticality, separating a condensed phase – where a microscopic fraction of agents holds a macroscopic share of total wealth – from a distributed phase with a light-tailed wealth distribution. While the original EYS model assumes fully connected interactions, this work introduces and studies a networked variant where agents interact over Erdős-Rényi random networks. The analysis combines Monte Carlo simulations with Quenched Mean Field and Mean Field approximations, exploring a variety of interaction and taxation schemes. A scaling analysis shows that, although the networked model also undergoes a continuous phase transition, it leads to local wealth condensation rather than the global condensation found in the fully connected case. These results deepen our understanding of wealth dynamics in structured populations and may help inform the development of more effective economic and social policies.
Statistical Mechanics (cond-mat.stat-mech), Disordered Systems and Neural Networks (cond-mat.dis-nn)
13 pages and 6 figures
Mean-field Mixed Quantum-Classical Approach for Many-Body Quantum Dynamics of Exciton-Polaritons
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-08 20:00 EDT
Pritha Ghosh, Arshath Manjalingal, Sachith Wickramasinghe, Saeed Rahmanian Koshkaki, Arkajit Mandal
In this work, we use a mixed quantum-classical (mean-field) many-body approach for simulating the quantum dynamics of excitons and exciton-polaritons beyond the single-excitation subspace. We combine the multitrajectory Ehrenfest approach, which propagates slow degrees of freedom classically, with the Gross-Pitaevskii method, which propagates fast degrees of freedom in a mean-field fashion. We use this mean-field many-body Ehrenfest approach to analyze how the phonon-induced dynamic disorder and the many-body interaction affect the incoherent and coherent dynamics of excitons and exciton-polaritons. We examine how the number of excitations and the strength of repulsive exciton-exciton interaction nonlinearly influence the transport, Fröhlich scattering and decoherence.
Materials Science (cond-mat.mtrl-sci), Optics (physics.optics), Quantum Physics (quant-ph)
Regional chemical potential analysis for material surfaces
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-08 20:00 EDT
Masahiro Fukuda, Masato Senami, Yoshiaki Sugimoto, Taisuke Ozaki
We propose a local regional chemical potential (RCP) analysis method based on an energy window scheme to quantitatively estimate the selectivity of atomic and molecular adsorption on surfaces, as well as the strength of chemical bonding forces between a probe tip and a surface in atomic force microscopy (AFM) measurements. In particular, focusing on the local picture of covalent bonding, we use a simple H2 molecular model to demonstrate a clear relationship between chemical bonding forces and the local RCP. Moreover, density functional theory calculations on molecular systems and diamond C(001) surfaces reveal that the local RCP at the surfaces success- fully visualizes electron-donating regions such as dangling bonds and double bonds. These results suggest that the local RCP can serve as an effective measure to analyze high-resolution non-contact or near-contact AFM images enhanced by chemical bonding forces.
Materials Science (cond-mat.mtrl-sci)
35 pages, 11 figures
Magnetic properties of nitrogen doped diamond: A first principles study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-08 20:00 EDT
The magnetic and electrical properties of nitrogen doped diamond system have been studied within the framework of a density functional theoretical approach. Spin-polarised calculations reveal that only the nitrogen doped system with adjacent carbon vacancies (NV-centre) leads to stable magnetism in N-doped diamond. The magnitude of the induced magnetic moment increases linearly with increasing number of NV centres in the system. This result explains earlier experimental reports suggesting unconventional magnetism in N-doped pristine diamond. The 2p-orbital electrons of the three carbon atoms adjacent to the vacancy contribute to the magnetic moment in the system. Notably, lone N at the lattice site in diamond system fails to induce any significant moment, whearas the C-vacancy and N-interstitial positions induce magnetic moment in the diamond system. Moreover, the NV-center system has p-type semiconducting characteristics, making it a potential candidate for spintronics applications. To quantify the feasibility of different systems, the magnetic moment, ground state free energy, Fermi energy and defect formation energy were calculated for each structure.
Materials Science (cond-mat.mtrl-sci)
Scalable Asynchronous Single Flux Quantum Up-Down Counter using Josephson Trapping Lines and α-Cells
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-08 20:00 EDT
Mustafa Altay Karamuftuoglu, Beyza Zeynep Ucpinar, Sasan Razmkhah, Massoud Pedram
We present a scalable, clockless up-down counter architecture implemented using single-flux quantum (SFQ) logic to enable efficient state management in superconductor digital systems. The proposed design eliminates the reliance on clocked storage elements by introducing the Josephson Trapping Line (JTrL). This bidirectional pulse-trapping structure enables persistent, non-volatile state storage without clocking. The counter integrates $ \upalpha$ -cells with a splitter (SPL) element to make bidirectional data propagation possible and support multi-fanout connectivity. The design supports increment, decrement, and read operations and includes a control unit that guarantees correct output behavior across all valid state transitions. Circuit-level simulations based on SPICE models demonstrate robust bidirectional functionality across a 3-bit state range [-4 to +4] at an operating frequency of 4 GHz. The proposed counter offers a modular and scalable solution suitable for integration into larger superconducting systems targeting quantum computing, neuromorphic processing, and cryogenic sensing applications.
Superconductivity (cond-mat.supr-con)
Differentiation of Distinct Single Atoms via Multi-Defocus Fusion Method
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-08 20:00 EDT
Yangfan Li, Yue Pan, Xincheng Lei, Weiwei Chen, Yang Shen, Mengshu Ge, Xiaozhi Liu, Dong Su
High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) is a vital tool for characterizing single-atom catalysts (SACs). However, reliable elemental identification of different atoms remains challenging because the signal intensity of HAADF depends strongly on defocus and other imaging parameters, potentially ruining the Z-contrast of atoms at different depths. In this work, we investigated the influence of the vertical position of atoms (defocus), support thickness, interatomic height, convergence and collection angles via multi-slice simulations on a model system of Fe/Pt atoms on amorphous carbon supports. Our calculation shows that at a convergence angle of 28 mrad, a defocus of 4.6 nm can cause Fe and Pt atoms indistinguishable. At a larger convergence angle, this critical indistinguishable defocus can be even shorter. To address this limitation, we propose a Multi-Defocus Fusion (MDF) method, retrieving the Z-contrast from serial images from multiple defocus. Experimental validation on a Fe/Pt SAC sample confirms the effectiveness of MDF, yielding clearly separated intensity histograms corresponding to Fe and Pt atoms. This work presents a robust, easy-to-implement strategy for accurate single-atom identification, offering valuable guidance for the accelerated screening and rational design of high-performance SACs.
Materials Science (cond-mat.mtrl-sci)
20 pages, 13 figures
Dynamic scaling of vorticity in phase-separating superfluid mixtures
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-05-08 20:00 EDT
Recently, it has been experimentally confirmed that non-equilibrium dynamics of phase separation in strongly ferromagnetic Bose-Einstein condensates of 7Li atoms obey the dynamic scaling law belonging to the binary- fluid universality class in the inertial hydrodynamic stage. The current work theoretically and numerically studies the dynamic scaling law of structure factor of vorticity in a phase-separating binary superfluid mixture, equivalent to the 7Li condensates in a strong limit of quadratic Zeeman shift. We found a dynamic scaling law for the structure factor based on our numerical observation that the peak of the energy spectrum from turbulence theory does not vary in time in the stage. Similarly to freely decaying turbulence, a power-law hierarchy exists in the energy spectrum in our system, and we proposed a decay law of the energy based on the dynamic scaling law by introducing the microscopic, high-wavenumber cutoff.
Quantum Gases (cond-mat.quant-gas)
Direct Bandgap Photoluminescence of GeSn grown on Si(100) substrate by Molecular Beam Epitaxy Growth
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-08 20:00 EDT
Diandian Zhang, Nirosh M. Eldose, Dinesh Baral, Hryhorii Stanchu, Sudip Acharya, Fernando Maia de Oliveira, Mourad Benamara, Haochen Zhao, Yuping Zeng, Wei Du, Gregory J. Salamo, Shui-Qing Yu
Group IV alloys of GeSn have gained significant attention for electronic and optoelectronic applications on a Si platform due to their compatibility with existing CMOS technology, tunable band structure, and potential for a direct bandgap at high Sn concentrations. However, synthesizing Sn-rich GeSn structures remains challenging due to the low solid solubility of Sn in Ge (less than 1%) and the substantial lattice mismatch ( about 14%) between Sn and Ge. In this work, we demonstrate the successful growth of high-quality, relaxed GeSn layers with Sn contents of 9.2% and 11.4% on Si(100) substrates via molecular beam epitaxy (MBE). As far as we know, this is the first report of direct bandgap photoluminescence observed from MBE-grown GeSn films without post-growth annealing. Structural characterizations including X-ray diffraction (XRD), secondary ion mass spectrometry (SIMS), and transmission electron microscopy (TEM) confirm uniform Sn incorporation with minimal defect formation. Atomic force microscopy (AFM) reveals smooth surfaces with low roughness. Temperature-dependent photoluminescence (PL) measurements further confirm direct bandgap emission, representing a new stage in the development of MBE-grown GeSn.
Materials Science (cond-mat.mtrl-sci)
12 pages,5 figures
A Mesoscale Model for Interface-Mediated Plasticity: Investigation of Ductile and Brittle Fracture
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-08 20:00 EDT
Jinxin Yu, Alfonso H. W. Ngan, David J. Srolovitzb, Jian Hana
The presence of interfaces and grain boundaries significantly impacts the mechanical properties of materials, particularly when dealing with micro- or nano-scale samples. Distinct interactions between dislocations and grain boundaries can lead to entirely different overall plastic deformation characteristics. This paper employs a two-dimensional continuum dislocation dynamics model to investigate the mechanical properties of materials. To accurately depict the physical interactions between lattice dislocations and interfaces/grain boundaries, we apply a mesoscale interface boundary condition, considering various numerical cases, such as single and multiple slip systems. Apart from affecting strength and ductility, the accumulation of dislocations near the interface can induce local high stress, potentially resulting in brittle fracture near the interface. Consequently, materials experience a competition between ductile and brittle fracture modes during the loading process. A phenomenon known as the strain hardening rate up-turn is also investigated under different reaction constants, which can be explained by the competition between the rates of dislocation accumulation and reaction at the interface.
Materials Science (cond-mat.mtrl-sci)
20 pages, 11 figures
Generic (fractional) quantum anomalous Hall crystals from interaction-driven band folding
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-08 20:00 EDT
Hongyu Lu, Han-Qing Wu, Bin-Bin Chen, Wang Yao, Zi Yang Meng
The experimental realizations of fractional quantum anomalous Hall (FQAH) states have been achieved recently, and there is a growing number of experiments in moiré systems showing the inequality between the filling of the Chern band and the quantized Hall conductance: $ \nu\neq\sigma_\mathrm{H}$ . Among many possible explanations, a popular one is that the topological states have coexisting charge density wave (CDW) orders, and such states are referred to as Hall crystals. However, apart from the experimental uncertainties, the generic mechanism of Hall crystals, especially those with fractional $ \sigma_\mathrm{H}$ is still elusive at the microscopic level. In this work, we numerically study a topological flat-band model and find that, the Chern band can be folded by the interaction-driven CDW, and a mini Chern band appears above the CDW gap. Through further analysis, we find the energy dispersion and the fluctuation of quantum geometry of the miniband could be flattened by competing interactions. When further doping this miniband, a series of (F)QAH states are found to coexist with the CDW order at (fractional)integer fillings of the miniband and the Hall conductivities of the FQAH crystals (FQAHCs)- determined by the fillings of the miniband - are different from the fillings of the original Chern band. We also study the thermodynamics of an FQAHC state and find the separation of energy scales and a compressible CDW phase at intermediate temperatures. Our work paves the way for the systematic understanding of (fractional) Hall crystals.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Crossover of Superconductivity across the end point of antiferromagnetic phase in FeSe${\rm 1-x}$S${\rm x}$ under pressure
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-08 20:00 EDT
Kiyotaka Miyoshi, Hironobu Nakatani, Yumi Yamamoto, Takumi Maeda, Daichi Izuhara, Ikumi Matsushima
Temperature-pressure ($ T$ -$ P$ ) phase diagrams of FeSe$ _{\rm 1-x}$ S$ {\rm x}$ were investigated by the measurements of dc magnetization ($ M$ ) and electrical resistivity ($ \rho$ ) under pressure, using single crystal specimens with $ x$ =0.04, 0.08 and 0.13. We observed a crossover of the superconductivity with increasing $ P$ near the end point of antiferromagnetic (AFM) phase, where two superconducting phases coexist within a pressure width of $ \Delta$ P$ \sim$ 1 GPa, having different $ T{\rm c}$ s. These results suggest that the superconducting phases inside and outside the AFM phase have different origins.
Superconductivity (cond-mat.supr-con)
6 pages, 3 figures
Complete suppression of flux instabilities in ramped superconducting magnets with synchronous temperature-modulated Jc
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-08 20:00 EDT
Cun Xue, Han-Xi Ren, Kai-Wei Cao, Wei Liu, Wen-Tao Zhang, Fang Yang, Guo Yan, You-He Zhou, Pingxiang Zhang
Nonlinear multifield coupling as an intrinsic property of complex physical systems often leads to abrupt and undesired this http URL currentramped high field Nb3Sn magnets, frequent flux jumps are observed, which easily causes premature quenches and requires prolonged and resourceintensive magnet training this http URL this study, we propose a paradigm shifting methodology framework that achieves complete suppression of thermomagnetic instabilities through synchronized temperature-modulated critical current density this http URL numerical simulations of flux jumps in multifilamentary Nb3Sn wires exposed to a time varying magnetic field at various temperatures, we construct thermomagnetic stability diagram in the Ha-T this http URL simulated results are in good agreement with experimental measurements, which demonstrates the synchronized ramped down temperature can indeed fully eliminate flux this http URL reveal the underlying physical mechanism of enhancing the thermomagnetic stability arises from that synchronized ramped-down temperature can continuously tune both Jc and its this http URL, we carry out numerical simulations for the thermomagnetic instabilities of current-ramped superconducting magnets through large-scale GPU-optimized algorithm with home-made codes. The flux jump and quench diagram in the Ia-T plane are this http URL indicates that the ramped-down temperature can completely suppress flux jumps without compromising Jc at high magnetic this http URL, this method does not require modifications to the superconducting microstructures or fabrication process, offering a practical and broadly applicable this http URL findings offer a robust method to stabilize diverse superconducting magnet systems (including 2nd-gen coated tape HTS magnets), and propose a generalizable strategy for controlling instability in nonlinear non-equilibrium physical systems.
Superconductivity (cond-mat.supr-con), Applied Physics (physics.app-ph)
A Predictive Theory of Electrochemical Ostwald Ripening for Electrodeposited Lithium Metal
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-08 20:00 EDT
Hanning Zhang, Oleg V. Yazyev, Ruslan Yamaletdinov
In this work, we present a theoretical framework that describes the evolution of lithium nuclei under the competing effects of electroplating and surface energy-driven redistribution (electrochemical Ostwald ripening). Our model introduces a formulation that accounts for solid electrolyte interphase (SEI) resistance, electrolyte conductivity, and electrode wettability, capturing the transition from SEI to electrolyte-limited growth regimes. We identify asymptotic behaviors for high and low current densities, quantify the conditions under which ripening dominates, and derive analytical expressions for nucleus size, density, and surface coverage. Model predictions show excellent agreement with experimental data across multiple datasets. The results reveal how SEI and electrolyte conductivity, current density and metal-electrode contact angle govern deposition morphology and Coulombic efficiency. Based on these insights, we outline experimentally accessible guidelines to improve battery efficiency and cycling stability - offering a simple yet predictive approach for optimizing metal electrodeposition processes in battery systems and beyond.
Materials Science (cond-mat.mtrl-sci), Soft Condensed Matter (cond-mat.soft), Chemical Physics (physics.chem-ph)
WKB energy levels in gapped graphene under crossed electromagnetic fields
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-08 20:00 EDT
I.O. Nimyi, S.G. Sharapov, V.P. Gusynin
We consider a single layer of graphene subjected to a magnetic field $ H$ applied perpendicular to the layer and an in-plane constant radial electric field $ E$ . The Dirac equation for this configuration does not admit analytical solutions in terms of known special functions. Using the WKB approximation, we demonstrate that for gapped graphene the Bohr-Sommerfeld quantization condition for eigenenergies includes an additional valley-dependent geometrical phase. When this term is accounted for, the WKB approximation exhibits good agreement with results from the exact diagonalization method except to the lowest Landau level.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
8 pages, 3 figures
Low Temp. Phys. 51, 588 (2025)
Diffusion in a wedge geometry: First-Passage Statistics under Stochastic Resetting
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-08 20:00 EDT
Fazil Najeeb, Arnab Pal, V.V. Prasad
We study the diffusion process in the presence of stochastic resetting inside a two-dimensional wedge of top angle $ \alpha$ , bounded by two infinite absorbing edges. In the absence of resetting, the second moment of the first-passage time diverges for $ \alpha>\pi/4$ while it remains finite for $ \alpha<\pi/4$ , resulting in an unbounded or bounded coefficient of variation in the respective angular regimes. Upon introducing stochastic resetting, we analyze the first-passage properties in both cases and identify the geometric configurations in which resetting consistently enhances the rate of absorption or escape through the boundaries. By deriving the expressions for the probability currents and conditional first-passage quantities such as splitting probabilities and conditional mean first-passage times, we demonstrate how resetting can be employed to bias the escape pathway through the favorable boundary. Our theoretical predictions are verified through Langevin-type numerical simulations, showing excellent agreement.
Statistical Mechanics (cond-mat.stat-mech)
10 pages, 7 figures
Defect engineering and effect of vacancy concentration on the electrochemical performance of V-based MXenes
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-08 20:00 EDT
Leiqiang Qin, Rutuparna Samal, Jianxia Jiang, Joseph Halim, Ningjun Chen, Florian Chabanais, Per O. A. Persson, Johanna Rosen
Vacancies play a pivotal role in determining the physical and chemical properties of materials. Introducing vacancies into two-dimensional (2D) materials offers a promising strategy for developing high-performance electrode materials for electrochemical energy storage. Herein, a facile top-down strategy is employed to create V-based MXenes with tunable vacancy concentrations, achieved by designing the precursor (V1-xCrx)2AlC (x=0.05, 0.1, 0.3) MAX phase and precisely controlling the etching process. Systematic investigations reveal that introducing a moderate concentration of Cr-induced vacancies significantly enhances both the capacitance and rate performance of V-based MXenes. Specifically, V1.9CTz achieves a capacitance of 760 F g-1, far exceeding the 420 F g-1 of vacancy-free V2CTz MXene. In contrast, an excessively high vacancy concentration lead to deteriorated electrochemical performance and compromised structural stability. This work illustrates that defect engineering is a powerful approach to tailor the electrochemical properties of MXenes, offering a framework for designing next-generation MXene-based energy storage systems.
Materials Science (cond-mat.mtrl-sci)
Exotic magnetic phase diagram and extremely robust antiferromagnetism in Ce$_2$RhIn$_8$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-08 20:00 EDT
T. Klein, C. Marcenat, A. Demuer, J. Sarrade, D. Aoki, I. Sheikin
The antiferromagnetic heavy-fermion compound Ce$ _2$ RhIn$ _8$ belongs to the same family and bears similarities with the well-studied prototypical material CeRhIn$ _5$ , which demonstrates a unique behavior under applied magnetic field. Here, we report specific-heat measurements on a high-quality single crystal of Ce$ _2$ RhIn$ _8$ in magnetic fields up to 35 T applied along both principal crystallographic directions. When the magnetic field is applied along the $ a$ axis of the tetragonal crystal structure, two additional field-induced antiferromagnetic phases are observed, in agreement with previous reports. One of them is confined in a small area of the field-temperature phase diagram. The other one, which develops above $ \sim$ 2.5 T, is very robust against the field. Its transition temperature increases with field, reaches a maximum at $ \sim$ 12 T, and then starts to decrease. However, it tends to saturate towards the highest field of our measurements. For a field applied along the $ c$ axis, the Néel temperature, $ T_N$ , initially decreases with field, as expected for a typical antiferromagnet. Surprisingly, an additional phase emerges above $ \sim$ 10 T. It is most likely to be of the same origin as its counterpart observed above 2.5 T for the other field orientation. This phase is also unusually robust: Its transition temperature increases all the way up to 35 T, where it exceeds the zero field $ T_N =$ ~2.85 K. Finally, for both field directions, the phase diagrams contain rarely observed tricritical points of second-order phase transitions.
Strongly Correlated Electrons (cond-mat.str-el)
6 pages, 4 figures. Accepted for publication as a Letter in Phys. Rev. B
Tangential Forces Govern the Viscous-Inertial Transition in Dense Frictional Suspensions
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-08 20:00 EDT
Sudarshan Konidena, Franco Tapia, Alireza Khodabakhshi, Elisabeth Guazzelli, Pascale Aussillous, Bernhard Vowinckel
We present particle-resolved simulations of dense frictional suspensions undergoing the viscous- inertial transition using pressure-imposed rheology. By varying the fluid viscosity, shear rate, and granular pressure, we find that the transition is independent of the packing fraction and occurs at a Stokes number of 10. Our results reveal that the shear stress exhibits a slower transition than the particle pressure, attributed to the combined effect of tangential contact and lubrication forces, as the frictional particles concurrently shift from rolling to sliding contacts. This shift is controlled by the Stokes number but also by the distance from jamming. Additionally, we examine the role of increasing inter-particle friction on the viscous-inertial transition.
Soft Condensed Matter (cond-mat.soft)
Spin-valve effect for spin-polarized surface states in topological semimetals
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-08 20:00 EDT
A.A. Avakyants, V.D. Esin, D.Yu. Kazmin, N.N. Orlova, A.V. Timonina, N.N. Kolesnikov, E.V. Deviatov
We experimentally investigate magnetoresistance of a single GeTe-Ni junction between the $ \alpha$ -GeTe topological semimetal and thick nickel film at room and liquid helium temperatures. For the magnetic field parallel to the junction plane, we demonstrate characteristic spin-valve hysteresis with mirrored differential resistance $ dV/dI$ peaks even at room temperature. In contrast, for normal magnetic fields spin-valve effect appears only at low temperatures. From the magnetic field anisotropy, observation of the similar effect for another topological semimetal Cd$ _3$ As$ _2$ , and strictly flat $ dV/dI(H)$ magnetoresistance curves for the reference GeTe-Au junction, we connect the observed spin-valve effect with the spin-dependent scattering between the spin textures in the topological surface states and the ferromagnetic nickel electrode. For the topological semimetal $ \alpha$ -GeTe, room-temperature spin-valve effect allows efficient spin-to-charge conversion even at ambient conditions.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Realizing high-temperature superconductivity in compressed molecular-hydrogen through Li doping
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-08 20:00 EDT
In this study, we explore lithium-doped stable molecular hydrogen structures by performing first-principles crystal structure searches across varying compositions in the Li-H system under high pressure. Our search reveals a cubic phase of LiH12, which shows promise as a high-temperature superconductor. Our Bader charge analysis suggests that electron transfer from Li to H atoms tunes the intra- and inter-molecular H-H distances, which are critical for the metallization of molecular hydrogen. This modulation alters the interaction between bonding and anti-bonding 1s states of hydrogen molecules. Furthermore, Li ions serve as stabilizers for the distorted H2 molecular network through ionic interactions. Numerical solutions to the fully anisotropic Migdal-Eliashberg equations reveals that this phase could exhibit superconductivity above 300 K at a pressure of 250 GPa, a pressure value that is typically achievable using a diamond anvil cell. Detailed analysis of species-specific phonons and the Eliashberg function shows that low- and intermediate-energy phonons are crucial in promoting strong electron-phonon coupling. Thus, our study establishes lithium doping as a promising approach to induce high-temperature superconductivity in compressed molecular hydrogen without causing molecular dissociation.
Superconductivity (cond-mat.supr-con)
30 pages,17 figures and 7 tables
Sign competing sources of Berry curvature and anomalous Hall conductance humps in topological ferromagnets
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-08 20:00 EDT
Wojciech Brzezicki, Carmine Autieri, Mario Cuoco
The use of Berry-phase concepts has established a strong link between the anomalous Hall effect (AHE) and the topological character of the Hall currents. However, the occurrence of sign competition in the Berry curvature often hin- ders the topological origin of the observed anomalous Hall effects. Here, we study a two-dimensional topological ferromagnet with coupled spin and orbital degrees of freedom to assess the anomalous Hall effects in the presence of sign- competing sources of Berry curvature. We show that 2D itinerant topological ferromagnets described by t2g electronic states can generally lead to topological metallic bands marked by a non-zero Chern number. We find that the resulting Berry curvature at the Fermi level exhibits a characteristic anisotropic profile with a non-monotonous angular dependence when the magnetization is reversed. The sign change of the intrinsic contribution to the anomalous Hall conductance can occur together with topological transitions or be driven by the population imbalance of the topological bands. The breaking of the inversion symmetry in- troduces the orbital Rashba coupling in the system. The interplay between the orbital Rashba and sign competing sources of Berry curvature leads to anoma- lies in the anomalous Hall conductance at values of magnetic fields for which the magnetization switches its orientation. The humps in topological ferromag- nets arise when the anomalous Hall conductivity is small in absolute value and they can be detected only close to the sign-change of the AHE and far from half-filling. This study could be relevant for the family of the topological 2D ferromagnets as well as Weyl ferromagnets, and can particularly account for the variety of unconventional behaviors observed in ultrathin films of SrRuO3.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
10 pages, 7 figures
Critical Behavior Analysis of Pure Dipolar Triangular Lattice via Equilibrium and Non-Equilibrium Monte Carlo Simulations
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-08 20:00 EDT
Magnetic thin films and 2D arrays of magnetic nanoparticles exhibit unique physical properties that make them valuable for a wide range of technological applications. In such systems, dipolar interactions play a crucial role in determining their physical behavior. However, due to the anisotropic and long-range nature of dipolar interactions, conventional Monte Carlo (MC) methods face challenges in investigating these systems near criticality. In this study, we examine the critical behavior of a triangular lattice of dipoles using the optimized Tomita MC algorithm tailored for dipolar interactions. We employ two independent computational approaches to estimate the critical temperature and exponents: equilibrium MC simulations with histogram reweighting and the non-equilibrium relaxation method. Notably, both approaches demonstrate that the critical exponents are very close to those of the 2D Ising universality class.
Statistical Mechanics (cond-mat.stat-mech), Computational Physics (physics.comp-ph)
10 pages. 11 figures
Magnetization-resolved density of states and quasi-first order transition in the two-dimensional random bond Ising model: an entropic sampling study
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-05-08 20:00 EDT
Yi Liu, Ding Wang, Xin Wang, Dao-Xin Yao, Lei-Han Tang
Systems with quenched disorder possess complex energy landscapes that are challenging to explore under the conventional Monte Carlo method. In this work, we implement an efficient entropy sampling scheme for accurate computation of the entropy function in low-energy regions. The method is applied to the two-dimensional $ \pm J$ random-bond Ising model, where frustration is controlled by the fraction $ p$ of ferromagnetic bonds. We investigate the low-temperature paramagnetic–ferromagnetic phase boundary below the multicritical point at $ T_N = 0.9530(4)$ , $ P_N = 0.89078(8)$ , as well as the zero-temperature ferromagnetic–spin-glass transition. Finite-size scaling analysis reveals that the phase boundary for $ T < T_N$ exhibits reentrant behavior. By analyzing the evolution of the magnetization-resolved density of states $ g(E, M)$ and ground-state spin configurations against increasing frustration, we provide strong evidence that the zero-temperature transition is quasi-first order. Finite-size scaling conducted on the spin-glass side supports the validity of $ \beta = 0$ , with a correlation length exponent $ \nu = 1.50(8)$ . Our results provide new insights into the nature of the ferromagnetic-to-spin-glass phase transition in an extensively degenerate ground state.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech)
27 pages, 10 figures
FRET-Enhanced Singlet Fission in Pentacene Derivatives
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-08 20:00 EDT
Oskar Kefer, Philipp Ludwig, Benedikt Dittmar, Felix Deschler, Jan Freudenberg, Andreas Dreuw, Uwe H.F. Bunz, Tiago Buckup
Conversion of solar energy with high quantum efficiencies is a key challenge in energy technologies. Excitation energy transfer (EET) mechanisms, such as Förster resonance energy transfer (FRET), play a crucial role in facilitating minimal energy loss in biological light-harvesting systems by directing excitation energy to conversion centers. Inspired by this, we show that singlet fission (SF) sensitizers are multi-exciton generation centers, to which surrounding molecules funnel excitation energy via FRET. We study the impact of such EET on SF using two structurally distinct yet optically similar pentacene derivatives: a stability-enhanced ‘’Geländer’’ pentacene, and the well-studied TIPS-pentacene. Transient absorption spectroscopy reveals a $ R^{6}$ dependence of the SF rate on molecular separation $ R$ in binary acene:polymethylmetacrylate thin film blends, which is typical for FRET. Optimizing FRET is a promising direction for future improvements in light harvesting using SF materials, inspired by natural light-harvesting complexes.
Materials Science (cond-mat.mtrl-sci)
7 pages, 3 figures, 1 supplementary information
Electromagnetic diffraction and bidirectional plasmon launching in partially gated 2d systems
New Submission | Other Condensed Matter (cond-mat.other) | 2025-05-08 20:00 EDT
Ilia Moiseenko, Egor Nikulin, Dmitry Svintsov
Partially gated two-dimensional electron systems (2DES) represent the basic building block of prospective optoelectronic devices, including electromagnetic detectors and sources. At the same time, the electrodynamic properties of such structures have been addressed only with numerical simulations. Here, we provide an exact solution of electromagnetic scattering problem at a partially gated 2DES using the Wiener-Hopf technique. We find that incident p-polarized field is enhanced in immediate vicinity of gate edge. The edge acts as a plasmonic coupler that launches bidirectional (gated and ungated) plasmons in weakly-dissipative 2DES with impedance of inductive type. Electric fields in these waves markedly exceeds the incident field, especially in the limit of small gate-2DES separation. The amplitude of the ungated wave exceeds that of gated for 2DES reactance above the free-space impedance. Both amplitudes are maximized for the 2DES reactance of the order of free space impedance timed by the ratio of free space wavelength and gate-2DES separation.
Other Condensed Matter (cond-mat.other)
Charged Vortex in Superconductor
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-08 20:00 EDT
Yoonbai Kim, SeungJun Jeon, Hanwool Song
We find the charged spinless vortices in the effective field theory of a Schrödinger type complex scalar field of Cooper pair, a U(1) gauge field of electromagnetism, and a gapless neutral scalar field of acoustic phonon. We show that regular static vortex solutions are obtained only for the nonzero critical cubic Yukawa type coupling between neutral and complex scalar fields. Since the Coulombic electric field is exactly cancelled by the phonon, the obtained charged vortices have finite energy. When the quartic self-interaction coupling of complex scalar field has the critical value, the BPS (Bogomolny-Prasad-Sommerfield) bound is saturated for multiple charged vortices of arbitrary separations and hence the borderline of type I and II superconductors is achieved in nonperturbative regime.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Theory (hep-th)
38 pages, 19 figures
Rotation-Induced Orbital Currents in Ferro-Rotational Systems
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-08 20:00 EDT
Generation of orbital angular momentum has become important to effectuate new ways to address switchable magnetic devices. Here, we demonstrate the electrical generation of unconventional orbital currents in ferro-rotational systems through an intrinsic, nonrelativistic mechanism associated with an electric hexadecapole moment. These rotation-induced orbital currents are examined using tight-binding models, and we also provide first-principles calculations for the ferro-rotational material TiAu$ _4$ . Our findings unveil a novel pathway for generating orbital currents beyond the conventional orbital Hall effect, broadening the landscape of orbitronics research to include novel ferroic materials and higher-order electric multipoles.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Screening of the band gap in electrically biased bilayer graphene: From Hartree to Hartree-Fock
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-08 20:00 EDT
Jack N. Engdahl, Zeb E. Krix, Oleg P. Sushkov
It is well known that a direct band gap may be opened in bilayer graphene via the application of a perpendicular electric field (bias). The bias and the chemical potential are controlled by electrostatic gating where the top and bottom gate voltages are tuned separately. The value of the band gap opened by the bias field is influenced by the self screening of the bilayer graphene. The Hartree contribution to the self screening is well known in literature, with Hartree screening significantly renormalizing the gap. In the present work we derive the Fock contribution to the self screening and demonstrate that it is equally important and in the low density regime even more important than the Hartree contribution. We calculate the Hartree-Fock screened band gap as a function of electron doping at zero temperature and also as a function of temperature at zero doping.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
11 pages, 8 figures
Replica exchange nested sampling
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-08 20:00 EDT
Nico Unglert, Livia Bartók Pártay, Georg K. H. Madsen
Nested sampling (NS) has emerged as a powerful tool for exploring thermodynamic properties in materials science. However, its efficiency is often hindered by the limitations of Markov chain Monte Carlo (MCMC) sampling. In strongly multimodal landscapes, MCMC struggles to traverse energy barriers, leading to biased sampling and reduced accuracy. To address this issue, we introduce replica-exchange nested sampling (RENS), a novel enhancement that integrates replica-exchange moves into the NS framework. Inspired by Hamiltonian replica exchange methods, RENS connects independent NS simulations performed under different external conditions, facilitating ergodic sampling and significantly improving computational efficiency. We demonstrate the effectiveness of RENS using four test systems of increasing complexity: a one-dimensional toy system, periodic Lennard-Jones, the two-scale core-softened Jagla model and a machine learned interatomic potential for silicon. Our results show that RENS not only accelerates convergence but also allows the effective handling of challenging cases where independent NS fails, thereby expanding the applicability of NS to more realistic material models.
Statistical Mechanics (cond-mat.stat-mech)
Advancements in Solid-State Sodium-Based Batteries: A Comprehensive Review
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-08 20:00 EDT
Arianna Massaro, Lorenzo Squillantini, Francesca De Giorgio, Francesca A. Scaramuzzo, Mauro Pasquali, Sergio Brutti
This manuscript explores recent advancements in solid-state sodium-based battery technology, particularly focusing on electrochemical performance and the challenges associated with developing efficient solid electrolytes. The replacement of conventional liquid electrolytes with solid-state alternatives offers numerous benefits, including enhanced safety and environmental sustainability, as solid-state systems reduce flammability and harsh chemical handling. The work emphasizes the importance of structure and interface characteristics in solid electrolytes, which play a critical role in ionic conductivity and overall battery performance. Various classes of solid electrolytes, such as sodium-based anti-perovskites and sulphide electrolytes, are examined, highlighting their unique ionic transport mechanisms and mechanical properties that facilitate stable cycling. The manuscript also discusses strategies to enhance interfacial stability between the anode and the solid electrolyte to mitigate performance degradation during battery operation. Furthermore, advancements in electrode formulations and the integration of novel materials are considered pivotal in optimizing the charging and discharging processes, thus improving the energy and power densities of sodium batteries. The outlook on the future of sodium-based solid-state batteries underscores their potential to meet emerging energy storage demands while leveraging the abundant availability of sodium compared to lithium. This comprehensive review aims to provide insights into ongoing research and prospective directions for the commercialization of solid-state sodium-based batteries, positioning them as viable alternatives in the renewable energy landscape.
Materials Science (cond-mat.mtrl-sci)
Direct evidence of intrinsic Mott state and its layer-parity oscillation in a breathing kagome crystal down to monolayer
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-08 20:00 EDT
Huanyu Liu, Wenhui Li, Zishu Zhou, Hongbin Qu, Jiaqi Zhang, Weixiong Hu, Chenhaoping Wen, Ning Wang, Hao Deng, Gang Li, Shichao Yan
We report direct spectroscopic evidence of correlation-driven Mott states in layered Nb$ _3$ Cl$ _8$ through combining scanning tunneling microscopy (STM) and dynamical mean-field theory. The Hubbard bands persist down to monolayer, providing the definitive evidence for the Mottness in Nb$ _3$ Cl$ _8$ . While the size of the Mott gap remains almost constant across all layers, a striking layer-parity-dependent oscillation emerges in the local density of states (LDOS) between even (n = 2,4,6) and odd layers (n = 1,3,5), which arises from the dimerization and correlation modulation of the obstructed atomic states, respectively. Our conclusions are supported by a critical technical advance in atomic-scale LDOS mapping for highly insulating systems. This work provides the definitive experimental verification of correlation-driven Mott ground states in Nb3Cl8 while establishing a general protocol for investigating the interplay of electronic correlation and interlayer coupling in layered insulators by using low-temperature STM technique.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
11 pages, 4 figures
Conduction Band Structure and Ultrafast Dynamics of Ferroelectric $α$-GeTe(111)
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-08 20:00 EDT
Geoffroy Kremer, Laurent Nicolaï, Frédéric Chassot, Julian Maklar, Christopher W. Nicholson, J. Hugo Dil, Juraj Krempaský, Gunther Springholz, Ralph Ernstorfer, Jan Minár, Laurenz Rettig, Claude Monney
$ \alpha$ -GeTe(111) is a non-centrosymmetric ferroelectric (FE) material for which a significative lattice distortion combined with a strong spin-orbit interaction gives rise to giant Rashba split states in the bulk and at the surface, which have been intensively probed in the occupied valence states using static angle-resolved photoemission spectroscopy (ARPES). Nevertheless, its unoccupied conduction band structure remains unexplored, in particular the experimental determination of its electronic band gap across momentum space. Using time-resolved ARPES based on high-repetition rate and extreme ultraviolet femtosecond (fs) laser, we unveil the band structure of $ \alpha$ -GeTe(111) in the full Brillouin zone, both in the valence and conduction states, as well as the exploration of its out-of-equilibrium dynamics. Our work confirms the semiconducting nature of $ \alpha$ -GeTe(111) with a 0.85 eV indirect band gap, which provides an upper limit for comparison to density functional theory calculations. We finally reveal the dominant scattering mechanisms of photoexcited carriers during the out-of-equilibrium dynamics under fs light pulses.
Materials Science (cond-mat.mtrl-sci)
9 pages, 5 figures (supplemental material available upon request)
Consistent Field Theory Across the Mott-Insulator to Superfluid Transition
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-05-08 20:00 EDT
Idan S. Wallerstein, Eytan Grosfeld
We employ a field-theoretical approach to analyze the Bose-Hubbard model on a lattice, with a focus on the low-energy properties across the Mott insulator (MI) to superfluid (SF) transition. Prior approaches approximated the partition function using cumulant expansions around the MI ground state, which, while accurate in the MI phase, lead to inaccuracies in the SF phase where the MI state is a false ground state. By expanding around the correct mean-field vacuum, we derive the effective field theory (EFT) governing the MI to SF transition. Through this, we reveal the underlying structure of the EFT governing the nucleation of low-energy excitations, particularly the massless and lowest massive modes, offering new insights into their emergence.
Quantum Gases (cond-mat.quant-gas), Other Condensed Matter (cond-mat.other)
9 pages, 5 figures
Revisiting the structure of epitaxial Si3N4 on AlGaN/GaN via evolutionary structure search
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-08 20:00 EDT
Gallium nitride (GaN)-based devices, such as high electron mobility transistors (HEMTs), benefit from the integration of a silicon nitride (Si3N4) cap layer on the AlGaN barrier. Previous studies, relying on empirical methods and the lack of systematic structure-searching tools, suggested a defect-wurtzite (DW-Si3N4) structure for Si3N4 on AlGaN. However, this structure, while plausible, is energetically much higher compared to beta-Si3N4. In a recent experiment (Appl. Phys. Lett. 125, 122109 (2024)), we synthesized a 2 nm thick crystalline Si3N4 layer on AlGaN. This finding prompted a reexamination of its atomic configuration, given the discrepancies between the previously proposed defect-wurtzite (DW) phase and experimental observations. To address this, we employed a systematic structure search to identify a more stable configuration, which we denote as Lam-Si3N4. This structure, characterized by a quasi-two-dimensional (Lamina) structure, is approximately 60 meV/atom lower in energy than the DW-Si3N4 structure under the in-plane lattice constant constraint matching AlGaN, and provides a better match to experimental data. Furthermore, when fully relaxed (i.e., no external strain), both DW-Si3N4 and Lam-Si3N4 exhibit wide band gaps around 4~eV. However, under the imposed AlGaN lattice constant constraint, the band gap of DW-Si3N4 significantly shrinks, whereas Lam-Si3N4 retains a relatively larger gap. The mechanical and phonon anisotropy in Lam-Si3N4 may lead to distinct directional thermal conductivity and elastic behavior, which can be beneficial for high-frequency and high-power applications. These findings provide important insights into the structure and properties of in situ grown Si3N4, potentially guiding further optimization of cap layers for GaN-based devices.
Materials Science (cond-mat.mtrl-sci)
TBA-enabled spin-coating of a percolatively connected GO nanosieve for thru-hole epitaxy: tuning GO flake stacking and coverage to control GaN nucleation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-08 20:00 EDT
Gunhoon Beak, Changwook Dong, Minah Choi, Jieun Yang, Joonwon Lim, Chinkyo Kim
We report a spin-coating-based approach for forming a percolatively connected graphene oxide (GO) nanosieve on SiO$ _2$ -patterned sapphire substrates, where the addition of tetrabutylammonium (TBA) to the GO solution significantly improves the uniformity of flake coverage and modulates GaN nucleation behavior. Upon thermal annealing of GO, the resulting reduced graphene oxide (rGO) films exhibit spatially varying coverage, leading to three distinct GaN nucleation outcomes: (i) ELOG-like nucleation on exposed substrate regions, (ii) thru-hole epitaxy (THE)-like nucleation through appropriately thin areas, and (iii) complete nucleation suppression on thickly stacked zones. On spin-coated GO films without TBA, all three behaviors coexist, and undesired ELOG- and no-nucleation modes persist due to uneven coverage. Importantly, these issues cannot be resolved by simply adjusting GO flake concentration, as concentration tuning alone fails to eliminate the formation of locally bare and overly thick regions. In contrast, the addition of TBA results in a more uniform, moderately stacked rGO morphology that suppresses both ELOG- and no-nucleation modes while expanding THE-like nucleation regions. This reshaped nucleation landscape confines GaN growth to areas with engineered percolative transport. The approach offers a scalable, lithography-free route for controlling GaN epitaxy using solution-processable 2D material masks.
Materials Science (cond-mat.mtrl-sci)
Reconfigurable Room Temperature Exchange Bias through Néel Order Switching in van der Waals Heterostructures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-08 20:00 EDT
Jicheng Wang, Shilei Ding, Bei Ding, Zhipeng Hou, Licong Peng, Yilan Jiang, Fengshan Zheng, Zhaochu Luo, Yu Ye, Jinbo Yang, Yanglong Hou, Rui Wu
Exchange bias effect plays a crucial role in modern magnetic memory technology. Recently, van der Waals magnetic materials have emerged and shown potential in spintronic devices at atomic scale. Owing to their tunable physical properties and the flexibility in fabrication, the van der Waals heterostructures offer more possibilities for investigating potential mechanisms of the exchange bias effect. However, due to low magnetic ordering temperatures for most van der Waals magnets, to establish exchange bias in van der Waals antiferromagnet/ferromagnet heterostructures at room temperature is challenging. In this study, we fabricate (Fe$ _{0.56}$ Co$ _{0.44}$ )$ _{5}$ GeTe$ _{2}$ (FCGT)/Fe$ _{3}$ GaTe$ _{2}$ (FGaT) heterostructures with magnetic ordering temperatures of each component well above room temperature to achieve a room temperature exchange bias effect. It is found that the sign and magnitude of the exchange bias field can be efficiently controlled by manipulating the Néel order of FCGT with magnetic field. The manipulation of Néel order shows significant magnetic field dependence. A strong pre-set field induces a switch in the Néel order of FCGT, which aligns the interfacial magnetization at the FCGT/FGaT interface, leading to robust exchange bias, as revealed by both transport measurements and macro-spin model calculations. Our findings demonstrate the intrinsic manipulation and switchable of room-temperature exchange bias in all-van der Waals heterostructures and further promote the development of novel two-dimensional spintronic devices.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
24 pages, 4 figures
Disordered solid to Bose-glass transition in Bose-Hubbard model with disorder and long-range interactions
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-05-08 20:00 EDT
Kohenjit Pebam, Laxmi Angom, Bhumika Thoudam, Momin Hrangbung, Deepak Gaur, Dilip Angom
The introduction of disorder in Bose-Hubbard model gives rise to new glassy quantum phases, namely the Bose-glass (BG) and disordered solid (DS) phases. In this work, we present the rich phase diagram of interacting bosons in disordered two-dimensional optical lattice, modelled by the disordered Bose-Hubbard model. We systematically probe the effect of long-range interaction truncated to the nearest neighbors and next-nearest neighbors on the phase diagram. We investigate the zero-temperature ground-state quantum phases using the single-site Gutzwiller mean field (SGMF) theory. We also employ strong-coupling perturbative expansion to identify the nature of ground-state solid phases analytically. At sufficiently high disorder strength, we observe a quantum phase transition between the DS and BG phases. We have investigated this transition in greater detail using cluster Gutzwiller mean field theory to study the effect of inter-site correlations which is absent in the SGMF method. We have also studied this phase transition from the perspective of percolation theory.
Quantum Gases (cond-mat.quant-gas)
11 pages, 9 figures
Ratchet Hall Effect in Fluctuating Superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-08 20:00 EDT
A. V. Parafilo, V. M. Kovalev, I. G. Savenko
We propose a superconducting ratchet-induced Hall effect (RHE), characterized by the emergence of a unidirectional, rectified flux of fluctuating Cooper pairs in a two-dimensional thin film exposed to an external electromagnetic field. The RHE is a second-order response with respect to the electromagnetic field amplitude. It consists of a nonzero photocurrent due to the breaking of the system’s inversion symmetry driven by the combined action of the in-plane time-dependent electric field and a spatial modulation of the critical temperature. We explore a means to control the electric current by the polarization of the external field accompanied by a non-linear Hall effect of fluctuating Cooper pairs caused by circularly polarized irradiation. Moreover, the nonlinear conductivity tensor exhibits a higher-power dependence on the reduced temperature compared to that of the conventional Aslamazov-Larkin correction (or other fluctuating second-order nonlinear responses). It results in a dramatic enhancement of the non-linear Hall response of fluctuating Cooper pairs in the vicinity of the superconducting criticality.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
All-DNA associative polymers
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-08 20:00 EDT
Francesco Tosti Guerra, Federico Marini, Francesco Sciortino, Lorenzo Rovigatti
Associative polymers (APs) with reversible, specific interactions between sticker'' sites exhibit a phase behavior that depends on a delicate balance between distinct contributions controlling the binding. For highly-bonded systems, it is entropy that mostly determines if, on increasing concentration, the network forms progressively or \textit{via} a first-order transition. With the aim of introducing an experimentally-viable system tailored to test the subtle dependence of the phase behavior on the binding site topology, here we numerically investigate AP polymers made of DNA, where sticker’’ sites made by short DNA sequences are interspersed in a flexible backbone of poly-T spacers. Due to their self-complementarity, each binding sequence can associate with another identical sticky sequence. We compare two architectures: one with a single sticker type, $ (AA)_6$ , and one with two distinct alternating types, $ (AB)_6$ . At low temperature, when most of the stickers are involved in a bond, the $ (AA)_6$ system remains homogeneous, while the $ (AB)_6$ system exhibits phase separation, driven primarily by entropic factors, mirroring predictions from simpler bead-spring models. Analysis of bond distributions and polymer conformations confirms that the predominantly entropic driving force behind this separation arises from the different topological constraints associated with intra- versus inter-molecular bonding. Our results establish DNA APs as a controllable, realistic platform for studying in the laboratory how the thermodynamics of associative polymer networks depends on the bonding site architecture in a clean and controlled way.
Soft Condensed Matter (cond-mat.soft)
8 pages, 6 figures
Accelerated escape dynamics in non-Markovian stochastic feedback
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-08 20:00 EDT
Francesco Coghi, Romain Duvezin, John S. Wettlaufer
We study the escape dynamics of a non-Markovian stochastic process with time-averaged feedback, which we model as a one-dimensional Ornstein–Uhlenbeck process wherein the drift is modified by the empirical mean of its trajectory. This process maps onto a class of self-interacting diffusions. Using weak-noise large deviation theory, we derive the most probable escape paths and quantify their likelihood via the action functional. We compute the feedback-modified Kramers rate and its inverse, which approximates the mean escape time, and show that the feedback accelerates escape by storing finite-time fluctuations thereby lowering the effective energy barrier, and shifting the optimal escape time from infinite to finite. Although we identify alternative mechanisms, such as slingshot and ballistic escape trajectories, we find that they remain sub-optimal and hence do not accelerate escape. These results show how memory feedback reshapes rare event statistics, thereby offering a mechanism to potentially control escape dynamics.
Statistical Mechanics (cond-mat.stat-mech), Probability (math.PR)
17 pages, 6 figures
Low-temperature transport in high-conductivity correlated metals: a density-functional plus dynamical mean-field study of cubic perovskites
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-08 20:00 EDT
Harrison LaBollita, Jeremy Lee-Hand, Fabian B. Kugler, Lorenzo Van Muñoz, Sophie Beck, Alexander Hampel, Jason Kaye, Antoine Georges, Cyrus E. Dreyer
While methods based on density-functional perturbation theory have dramatically improved our understanding of electron-phonon contributions to transport in materials, methods for accurately capturing electron-electron scattering relevant to low temperatures have seen significantly less development. The case of high-conductivity, moderately correlated materials characterized by low scattering rates is particularly challenging, since exquisite numerical precision of the low-energy electronic structure is required. Recent methodological advancements to density-functional theory combined with dynamical mean-field theory (DFT+DMFT), including adaptive Brillouin-zone integration and numerically precise self-energies, enable a rigorous investigation of electron-electron scattering in such materials. In particular, these tools may be leveraged to perform a robust scattering-rate analysis on both real- and imaginary-frequency axes. Applying this methodology to a subset of ABO$ _3$ perovskite oxides – SrVO$ _3$ , SrMoO$ _3$ , PbMoO$ _3$ , and SrRuO$ _3$ – we demonstrate its ability to qualitatively and quantitatively describe electron-electron contributions to the temperature-dependent direct-current resistivity. This combination of numerical techniques offers fundamental insight into the role of electronic correlations in transport phenomena and provides a predictive tool for identifying materials with potential for technological applications.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
16 pages, 11 figures
Large-scale exponential correlations of non-affine elastic response of strongly disordered materials
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-05-08 20:00 EDT
D. A. Conyuh, D. V. Babin, I. O. Raikov, Y. M. Beltukov
The correlation properties of non-affine elastic response in strongly disordered materials are investigated using the theory of correlated random matrices and molecular dynamics simulations. The random matrix theory shows that the divergence of the non-affine displacement field has large-scale exponentially decaying correlations. The corresponding length scale $ \xi$ is determined by the strength of the disorder and can be indefinitely large, significantly exceeding the correlation length of the disorder. The rotor of the non-affine displacement field has the same length scale $ \xi$ except the case of the volumetric deformation. The main theoretical dependencies are confirmed by molecular dynamics simulation of a model polystyrene in the amorphous state.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Materials Science (cond-mat.mtrl-sci)
Nanoscale Mechanical Structures Fabricated from Silicon-on-Insulator Substrates
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-08 20:00 EDT
Andrew N. Cleland, Michael L. Roukes
We describe a method with which to fabricate sub-micron mechanical structures from silicon-on-insulator substrates. We believe this is the first reported method for such fabrication, and our technique allows for complex, multilayer electron beam lithography to define metallized layers and structural Si layers on these substrates. The insulating underlayer may be removed by a straightforward wet processing step, leaving suspended single crystal Si mechanical structures. We have fabricated and mechanically tested structures such as beam resonators, tuning-fork resonators, and torsional oscillators, all with smallest dimensions of 0.1-0.2 microns and fundamental resonance frequencies above 10 MHz.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
Submitted to Applied Physics Letters in 1996. Rejected by a single referee with the criticism that it was not a sufficient advance over our previous publication (on NEMS fabrication from bulk Si wafers) to warrant acceptance in APL. However, the method described herein has since become the standard fabrication method in the field of NEMS, and used worldwide over the past thirty years
Engineering topological exciton structures in two-dimensional semiconductors by a periodic electrostatic potential
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-08 20:00 EDT
We propose to engineer topological exciton structures in layered transition metal dichalcogenides through hybridizing different Rydberg states, which can be induced by a periodic electrostatic potential remotely imprinted from charge distributions in adjacent layers. Topological phase diagrams are obtained for potentials with various strengths and wavelengths. We find the lowest band of the interlayer exciton can become topologically nontrivial, which exhibits a small bandwidth as well as quantum geometries well suited for realizing the bosonic fractional Chern insulator. For monolayer excitons, topological bands and in-gap helical edge states can emerge near the energy of 2p states.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)