CMP Journal 2025-07-15
Statistics
Physical Review Letters: 4
Physical Review X: 2
arXiv: 112
Physical Review Letters
High-Stability Single-Ion Clock with $5.5\times{}{10}^{- 19}$ Systematic Uncertainty
Research article | Atomic, optical & lattice clocks | 2025-07-14 06:00 EDT
Mason C. Marshall, Daniel A. Rodriguez Castillo, Willa J. Arthur-Dworschack, Alexander Aeppli, Kyungtae Kim, Dahyeon Lee, William Warfield, Joost Hinrichs, Nicholas V. Nardelli, Tara M. Fortier, Jun Ye, David R. Leibrandt, and David B. Hume
A new trap design with reduced micromotion, more accurate measurements of the ion’s Doppler-cooled temperature and differential polarizability by Doppler cooling light, and improved laser stabilization allows for an atomic clock with the lowest fractional frequency uncertainty of any to date.
Phys. Rev. Lett. 135, 033201 (2025)
Atomic, optical & lattice clocks, Quantum nondemolition measurement, Trapped ions, Polarizability, Atom & ion cooling
Toward Nonlinear Optics with M"ossbauer Nuclei Using X-Ray Cavities
Research article | Cavity quantum electrodynamics | 2025-07-14 06:00 EDT
Dominik Lentrodt, Christoph H. Keitel, and Jörg Evers
Strong excitation of nuclear resonances, particularly of M"ossbauer nuclei, has been a longstanding goal and the advance of novel x-ray sources is promising new options in this regard. Here, we map out the necessary experimental conditions for the more general goal of entering the nonlinear optics regime with nuclei and compare with available technology. In particular, we present a comprehensive theory of nonlinear nuclear excitation in thin-film x-ray cavities by focused x-ray pulses. We thereby identify cavity geometries with broad resonances that allow one to boost the nuclear excitation even at moderately tight focusing and offer the possibility to mitigate radiation damage.
Phys. Rev. Lett. 135, 033801 (2025)
Cavity quantum electrodynamics, Light-matter interaction, Nonlinear optics, Nuclear & electron resonance, Quantum optics, X-ray beams & optics, Quantum cavities, X-ray lasers, Two-level models
New Classes of Quantum Anomalous Hall Crystals in Multilayer Graphene
Research article | Fractional quantum Hall effect | 2025-07-14 06:00 EDT
Boran Zhou and Ya-Hui Zhang
Quantum anomalous Hall crystal states with larger periods than the moiré period exist at filling factor ν = 1.
Phys. Rev. Lett. 135, 036501 (2025)
Fractional quantum Hall effect, Quantum anomalous Hall effect, Graphene, Wigner crystal
Anyonic Phase Transitions in the 1D Extended Hubbard Model with Fractional Statistics
Research article | Anyons | 2025-07-14 06:00 EDT
Martin Bonkhoff, Kevin Jägering, Shijie Hu, Axel Pelster, Sebastian Eggert, and Imke Schneider
We study one-dimensional lattice anyons with extended Hubbard interactions at unit filling using bosonization and numerical simulations. The behavior can be continuously tuned from bosonic to fermionic statistics by adjusting the topological exchange angle $\theta $, which leads to a competition of different instabilities. We present the bosonization theory in the presence of dynamic gauge fields, which predicts a phase diagram of four different gapped phases with distinct dominant correlations. Advanced numerical simulations determine and analyze the exact phase transitions between Mott insulator, charge density wave, dimerized state, and Haldane insulator, all of which meet at a multicritical line in the parameter space of anyonic angle $\theta $, on-site interaction $U$, and nearest neighbor repulsion $V$. Superfluid and pair-superfluid phases are stable in a region of small $V$.
Phys. Rev. Lett. 135, 036601 (2025)
Anyons, Cold atoms & matter waves, Critical phenomena, Phase transitions, Quantum phase transitions, 1-dimensional systems, Density matrix renormalization group, Extended Hubbard model, Luttinger liquid model
Physical Review X
Massively Multiplexed Nanoscale Magnetometry with Diamond Quantum Sensors
Research article | Magnetometry | 2025-07-14 06:00 EDT
Kai-Hung Cheng, Zeeshawn Kazi, Jared Rovny, Bichen Zhang, Lila S. Nassar, Jeff D. Thompson, and Nathalie P. de Leon
Two independent groups optimize diamond-based quantum sensing by using more than 100 such sensors in parallel.
Phys. Rev. X 15, 031014 (2025)
Magnetometry, NV centers, Quantum sensing, Correlation function measurements
Scalable Parallel Measurement of Individual Nitrogen-Vacancy Centers
Research article | NV centers | 2025-07-14 06:00 EDT
Matthew Cambria, Saroj Chand, Caitlin Mary Reiter, and Shimon Kolkowitz
Two independent groups optimize diamond-based quantum sensing by using more than 100 such sensors in parallel.
Phys. Rev. X 15, 031015 (2025)
NV centers, Quantum metrology, Quantum sensing
arXiv
Static and dynamic ordering of magnetic repelling particles under confinement: disks vs bars
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-15 20:00 EDT
M. Aguilar-González, L. F. Elizondo-Aguilera, Y.D. Sobral, F. Pacheco-Vázquez
We explored experimentally the self-organization at rest and the compression dynamics of a two-dimensional array of magnetic repelling particles, using two particle geometries, namely, disks and rectangular bars. Despite the non-contact interaction, typical static features of granular materials are observed for both particle shapes: pile formation with an angle of repose and pressure saturation (Janssen-like effect), which can be explained by considering the magnetically-induced torques that generate friction between particles and confining walls. Particle shape effects are mainly observed during compression: while disks rearrange increasing the hexagonal ordering, bars augment their orientational ordering forming larger non-contact force chains; however, in both cases, the resistance to compression rises continuously, in contrast with the fluctuating compression dynamics (stick-slip motion or periodic oscillations) that characterizes granular systems with inter-particle contacts. The continuous response to compression, and the reduction of particle wear due to non-contact interactions, are desirable features in designing magnetic granular dampers.
Soft Condensed Matter (cond-mat.soft), Applied Physics (physics.app-ph), Classical Physics (physics.class-ph), Fluid Dynamics (physics.flu-dyn)
18 pages, 12 figures, Granular matter
Exploring global landscape of free energy for the coupled Cahn-Hilliard equations
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-15 20:00 EDT
Keiichiro Kagawa, Takeshi Watanabe, Yasumasa Nishiura
Describing the complex landscape of infinite-dimensional free energy is generally a challenging problem. This difficulty arises from the existence of numerous minimizers and, consequently, a vast number of saddle points. These factors make it challenging to predict the location of desired configurations or to forecast the trajectories and pathways leading from an initial condition to the final state. In contrast, experimental observations demonstrate that specific morphologies can be reproducibly obtained in high yield under controlled conditions, even amidst noise. This study investigates the possibility of elucidating the global structure of the free energy landscape and enabling the control of orbits toward desired minimizers without relying on exhaustive brute-force methods. Furthermore, it seeks to mathematically explain the efficacy of certain experimental setups in achieving high-yield outcomes. Focusing on the phase separation of two polymers in a solvent, we conduct a one-dimensional analysis that reveals the global free energy landscape and relaxation-parameter-dependent trajectory behaviors. Two key methodologies are developed: one is a saddle point search method, akin to bifurcation tracking. This method aims to comprehensively identify all saddle points. The other is a strategy that adjusts the relaxation parameters preceding each variable’s time derivative, aligning with experimental setups. This approach enables control over trajectory behaviors toward desired structures, overcoming the limitations of steepest descent methods. By tuning these relaxation parameters, uncertainties in trajectory behavior due to inevitable fluctuations can be suppressed. These methodologies collectively offer a mathematical framework that mirrors experimental high-yield phenomena, facilitating a deeper understanding of the underlying mechanisms.
Soft Condensed Matter (cond-mat.soft), Dynamical Systems (math.DS)
33 pages, 20 figures, 6 tables
Gigantic dynamical spreading and anomalous diffusion of jerky active particles
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-15 20:00 EDT
Jerky active particles are Brownian self-propelled particles which are dominated by ``jerk’’, the change in acceleration. They represent a generalization of inertial active particles. In order to describe jerky active particles, a linear jerk equation of motion which involves a third-order derivative in time, Stokes friction and a spring force is combined with activity modeled by an active Ornstein-Uhlenbeck process. This equation of motion is solved analytically and the associated mean-square displacement (MSD) is extracted as a function of time. For small damping and small spring constants, the MSD shows an enormous superballistic spreading with different scaling regimes characterized by anomalous high dynamical exponents 6, 5, 4 or 3 arising from a competition between jerk, inertia and activity. When exposed to a harmonic potential, the gigantic spreading tendency induced by jerk gives rise to an enormous increase of the kinetic temperature and even to a sharp localization-delocalization transition, i.e. a jerky particle can escape from harmonic confinement. The transition can be either first or second order as a function of jerkiness. Finally it is shown that self-propelled jerky particles governed by the basic equation of motion can be realized experimentally both in feedback-controlled macroscopic particles and in active colloids governed by friction with memory.
Soft Condensed Matter (cond-mat.soft)
Sensing the binding and unbinding of anyons at impurities
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-15 20:00 EDT
Anyons are quasiparticles with fractional charge and statistics that arise in strongly correlated two-dimensional systems such as the fractional quantum Hall (FQH) effect and fractional Chern insulators (FCI). Interactions between anyons can lead to emergent phenomena, such as anyon superconductivity as well as anyon condensation which allows for a hierarchical construction of quantum Hall states. In this work, we study how quasihole anyons in a $ \nu=1/3$ Laughlin fractional quantum Hall state can be bound together by a sufficiently strong attractive impurity potential. The competition between the repulsive interaction between the quasiholes themselves and the attractive interaction between the quasiholes and the impurity leads to states with different numbers of quasiholes bound to the impurity. Tuning the chemical potential via gating while remaining within a quantum Hall plateau changes the number of quasiholes bound to the impurity. We propose methods for studying these states experimentally, for example using scanning tunneling microscopy and exciton spectroscopy. While the impurities in traditional platforms such as GaAs heterostructures are typically too weak to observe the binding of anyons, the recently discovered zero-field fractional Chern insulators in twisted MoTe$ _2$ offer a platform which may realize the strong-impurity regime.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
10 pages, 6 figures
Anyon-trions in atomically thin semiconductor heterostructures
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-15 20:00 EDT
Nader Mostaan, Nathan Goldman, Ataç İmamoğlu, Fabian Grusdt
The study of anyons in topologically ordered quantum systems has mainly relied on edge-state interferometry. However, realizing controlled braiding of anyons necessitates the ability to detect and manipulate individual anyons within the bulk. Here, we propose and theoretically investigate a first step toward this goal by demonstrating that a long-lived, optically generated interlayer exciton can bind to a quasihole in a fractional quantum Hall state, forming a composite excitation we term an anyon-trion. Using exact diagonalization, we show that mobile anyon-trions possess a binding energy of approximately 0.5 meV, whereas static anyon-trions exhibit a binding energy of about 0.9 meV, that is linearly proportional to the quasiholes fractional charge. An experimental realization based on photoluminescence from localized interlayer excitons in a quantum twisting microscope setup should allow for a direct optical observation of anyon-trions.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Gases (cond-mat.quant-gas), Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
Addressing the Infinite Variance Problem in Fermionic Monte Carlo Simulations: Retrospective Error Remediation and the Exact Bridge Link Method
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-15 20:00 EDT
We revisit the infinite variance problem in fermionic Monte Carlo simulations, which is widely encountered in areas ranging from condensed matter to nuclear and high-energy physics. The different algorithms, which we broadly refer to as determinantal quantum Monte Carlo (DQMC), are applied in many situations and differ in details, but they share a foundation in field theory, and often involve fermion determinants whose symmetry properties make the algorithm sign-problem-free. We show that the infinite variance problem arises as the observables computed in DQMC tend to form heavy-tailed distributions. To remedy this issue retrospectively, we introduce a tail-aware error estimation method to correct the otherwise unreliable estimates of confidence intervals. Furthermore, we demonstrate how to perform DQMC calculations that eliminate the infinite variance problem for a broad class of observables. Our approach is an exact bridge link method, which involves a simple and efficient modification to the standard DQMC algorithm. The method introduces no systematic bias and is straightforward to implement with minimal computational overhead. Our results establish a practical and robust solution to the infinite variance problem, with broad implications for improving the reliability of a variety of fundamental fermion simulations.
Strongly Correlated Electrons (cond-mat.str-el), Computational Physics (physics.comp-ph)
11 pages + appendix, 8 figures
Thermodynamic Geometric Constraint on the Spectrum of Markov Rate Matrices
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-15 20:00 EDT
Guo-Hua Xu, Artemy Kolchinsky, Jean-Charles Delvenne, Sosuke Ito
The spectrum of Markov generators encodes physical information beyond simple decay and oscillation, which reflects irreversibility and governs the structure of correlation functions. In this work, we prove an ellipse theorem that provides a universal thermodynamic geometric constraint on the spectrum of Markov rate matrices. The theorem states that all eigenvalues lie within a specific ellipse in the complex plane. In particular, the imaginary parts of the spectrum, which indicate oscillatory modes, are bounded by the maximum thermodynamic force associated with individual transitions. This spectral bound further constrains the possible values of correlation functions of two arbitrary observables. Finally, we compare our result with a previously proposed conjecture, which remains an open problem and warrants further investigation.
Statistical Mechanics (cond-mat.stat-mech)
6 pages, 3 figures in main text; 2 pages, 1 figure in End Matter; 3 pages, 6 figures in Supplementary Material
Structural optimization of lattice-matched Sc0.14Al0.86N/GaN superlattices for photonic applications
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-15 20:00 EDT
Rajendra Kumar, Govardan Gopakumar, Zain Ul Abdin, Michael J. Manfra, Oana Malis
ScxAl1-xN is an emerging III-nitride material known for its high piezoelectric coefficient and ferroelectric properties. Integration of wide-bandgap ScxAl1-xN with GaN is particularly attractive for quantum photonic devices. Achieving low defect complex multilayers incorporating ScxAl1-xN, though, requires precise lattice-matching and carefully optimized growth parameters. This study systematically investigates the molecular-beam epitaxy of short-period ScxAl1-xN/GaN superlattices with total thicknesses of up to 600 nm on GaN templates. X-ray diffraction reciprocal space mapping confirmed lattice-matching at x = 0.14 Sc composition regardless of the thickness of GaN interlayers, as evidenced by symmetric superlattice satellites aligned in-plane with the underlying substrate peak. Superlattices with Sc compositions deviating from this lattice-matching condition exhibited strain-induced defects ranging from crack formation to partial relaxation. Scanning transmission electron microscopy (STEM) investigation of the ScxAl1-xN/GaN interfaces identified temperature-dependent intermixing as a major factor in setting the nitride composition variation and implicitly band structure profile along the growth direction. Energy-dispersive X-ray spectroscopy also revealed that Sc incorporation exhibits delays relative to Al at both onset and termination. Optimal growth conditions were observed at approximately 600°C and 550°C for superlattices with thick GaN layers (6 nm), and ultra-thin GaN layers (< 2 nm), respectively.
Materials Science (cond-mat.mtrl-sci)
Universal scaling of microwave dissipation in superconducting circuits
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-15 20:00 EDT
Thibault Charpentier, Anton Khvalyuk, Lev Ioffe, Mikhail Feigel’man, Nicolas Roch, Benjamin Sacépé
Improving the coherence of superconducting qubits is essential for advancing quantum technologies. While superconductors are theoretically perfect conductors, they consistently exhibit residual energy dissipation when driven by microwave currents, limiting coherence times. Here, we report a universal scaling between microwave dissipation and the superfluid density, a bulk property of superconductors related to charge carrier density and disorder. Our analysis spans a wide range of superconducting materials and device geometries, from highly disordered amorphous films to ultra-clean systems with record-high quality factors, including resonators, 3D cavities, and transmon qubits. This scaling reveals an intrinsic bulk dissipation channel, independent of surface dielectric losses, that originates from a universal density of nonequilibrium quasiparticles trapped within disorder-induced spatial variations of the superconducting gap. Our findings define a fundamental limit to coherence set by intrinsic material properties and provide a predictive framework for selecting materials and the design of next-generation superconducting quantum circuits.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con), Quantum Physics (quant-ph)
Contact Forces in Motility-Regulated Active Matter
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-15 20:00 EDT
Quan Manh Nguyen, Alberto Dinelli, Gianmarco Spera, Julien Tailleur
Long-range interactions are ubiquitous in nature, where they are mediated by diffusive fields at the cellular scale or by visual cues for groups of animals. Short-range forces, which are paradigmatic in physics, can thus often be neglected when modeling the collective behaviors of biological systems induced by mediated interactions. However, when self-organization leads to the emergence of dense phases, we show that excluded-volume interactions play an important and versatile role. We consider assemblies of active particles that undergo either condensation or phase-separation due to motility regulation and show that short-range repulsive forces can induce opposite effects. When motility regulation triggers an absorbing phase transition, such as a chemotactic collapse, repulsive forces opposes the formation of condensates and stabilize the coexistence between finite-density phases. In contrast, when motility regulation induces liquid-gas coexistence, repulsive forces can, counterintuitively, lead to a significant increase in the liquid density.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
7 pages, 5 figures, and SM
Anisotropic magnetism of polymorphic ErAl3
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-15 20:00 EDT
Karolina Gornicka, Brenden R. Ortiz, Andrew D. Christianson, Andrew F. May
ErAl$ _3$ can form in either a trigonal ($ \alpha$ ) or cubic ($ \beta$ ) polymorph and this paper investigates the physical properties of these polymorphs through characterizations of single crystals grown in an aluminum flux. We demonstrate that polymorph selection can be achieved based on the nominal composition of the crystal growth. Magnetic measurements confirm that both $ \beta$ -ErAl$ _3$ and $ \alpha$ -ErAl$ _3$ order antiferromagnetically at low temperatures. $ \beta$ -ErAl$ _3$ undergoes AFM ordering at a Néel temperature T$ _N$ = 5.1 K, and the transition is suppressed continually with applied field. $ \alpha$ -ErAl$ _3$ displays more complex behavior, with successive magnetic transitions at T$ _N$ = 5.7 K and T$ _2$ = 4.6 K for zero field, where heat capacity and dilatometry measurements evidence that these transitions are second- and first-order, respectively. Under magnetic field, strong anisotropy is revealed in $ \alpha$ -ErAl$ _3$ , with several step-like metamagnetic transitions observed below T$ _2$ for H$ \parallel$ c. These transitions produce sequential magnetization plateaus near one-half of the apparent saturation magnetization. The electrical resistivity of $ \alpha$ -ErAl$ _3$ is strongly coupled to its magnetism. At $ T$ = 2 K, we observe a positive magnetoresistance reaching 60%, with distinct anomalies at the metamagnetic transitions. The results are summarized in $ H$ - $ T$ phase diagrams that demonstrate complex magnetic behavior for $ \alpha$ -ErAl$ _3$ , suggesting an important role of competing interactions in this metallic system that possesses characteristics of Ising physics.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Phys. Rev. Materials 8, 114412 (2024)
Counterflow leads to roton spectra in locally interacting superfluids
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-07-15 20:00 EDT
Samuel Alperin, Eddy Timmermans
The dynamics of strongly interacting quantum fluids such as Helium II are fundamentally distinct from those of dilute, contact-interacting atomic Bose-Einstein condensates. Most dramatically, superfluids with finite-range interactions can support excitations with a roton-like dispersion, exhibiting a minimum at finite wavenumber. Here we introduce a mechanism through which roton spectra can emerge in superfluids without any nonlocal interactions, instead resulting from the collective excitations of two counterflowing, zero-range interacting condensates. As our mechanism relies only on the nonlinear dynamics of classical fields, this work opens the door to the realization of roton dynamics in the broad class of physical systems governed by coupled nonlinear-Schrödinger equations.
Quantum Gases (cond-mat.quant-gas), Pattern Formation and Solitons (nlin.PS)
Electrostatically Assembled Open Square and Checkerboard Superlattices
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-15 20:00 EDT
Binay P. Nayak, Wenjie Wang, Honghu Zhang, Benjamin M. Ocko, Alex Travesset, Surya K. Mallapragada, David Vaknin
Programmable assembly of nanoparticles into structures other than hexagonal lattices remains challenging. Assembling an open checkerboard or square lattice is harder to achieve compared to a close-packed hexagonal structure. Here, we introduce a unified, robust approach to assemble nanoparticles into a diverse family of two-dimensional superlattices at the liquid-air interface. Gold nanoparticles are grafted with pH-responsive, water-soluble poly(ethylene glycol) chains terminating in -COOH or -NH2 end groups, enabling control over interparticle interactions, while the grafted polymer’s molecular weight dictates its conformation. This combined control crystallizes checkerboard, simple-square, and body-centered honeycomb superlattices. We find that even for identical nanoparticle core sizes, the polymer’s molecular weight dictates superlattice symmetry and stability. Furthermore, tuning pH induces structural transitions between different lattice types. This method opens new avenues for the programmable fabrication of colloidal superstructures with tailored architectures.
Soft Condensed Matter (cond-mat.soft), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Surprisingly High Redundancy in Electronic Structure Data
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-15 20:00 EDT
Sazzad Hossain, Ponkrshnan Thiagarajan, Shashank Pathrudkar, Stephanie Taylor, Abhijeet S. Gangan, Amartya S. Banerjee, Susanta Ghosh
Machine Learning (ML) models for electronic structure rely on large datasets generated through expensive Kohn-Sham Density Functional Theory simulations. This study reveals a surprisingly high level of redundancy in such datasets across various material systems, including molecules, simple metals, and complex alloys. Our findings challenge the prevailing assumption that large, exhaustive datasets are necessary for accurate ML predictions of electronic structure. We demonstrate that even random pruning can substantially reduce dataset size with minimal loss in predictive accuracy, while a state-of-the-art coverage-based pruning strategy retains chemical accuracy and model generalizability using up to 100-fold less data and reducing training time by threefold or more. By contrast, widely used importance-based pruning methods, which eliminate seemingly redundant data, can catastrophically fail at higher pruning factors, possibly due to the significant reduction in data coverage. This heretofore unexplored high degree of redundancy in electronic structure data holds the potential to identify a minimal, essential dataset representative of each material class.
Materials Science (cond-mat.mtrl-sci), Disordered Systems and Neural Networks (cond-mat.dis-nn), Machine Learning (cs.LG), Computational Physics (physics.comp-ph), Quantum Physics (quant-ph)
On failure mechanisms and load-parallel cracking in confined elastomeric layers
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-15 20:00 EDT
Thin layers of elastomers bonded to two rigid plates demonstrate unusual failure response. Historically, it has been believed that strongly-bonded layers fail by two distinct mechanisms: (i) internal/external penny-shaped crack nucleation and propagation, and (ii) cavitation, that is, cavity growth leading to fibrillation and then failure. However, recent work has demonstrated that cavitation itself is predominantly a fracture process. While the equations describing cavitation from a macroscopic or top-down view are now known and validated with experiments, several aspects of the cavitation crack growth need to be better understood. Notably, cavitation often involves through-thickness crack growth parallel to the loading direction, raising questions about when it initiates instead of the more typical penny-shaped cracks perpendicular to the load. Understanding and controlling the two vertical and horizontal crack growth is key to developing tougher soft films and adhesives. The purpose of this Letter is to provide an explanation for the load-parallel crack growth through a comprehensive numerical analysis and highlight the role of various material and geometrical parameters.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
Molecular Arrangements in the First Monolayer of Cu-Phthalocyanine on In$_2$O$_3$(111)
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-15 20:00 EDT
Matthias Blatnik, Fabio Calcinelli, Andreas Jeindl, Moritz Eder, Michael Schmid, Jan Čechal, Ulrike Diebold, Peter Jacobson Oliver T. Hofmann, Margareta Wagner
Well-ordered organic molecular layers on oxide surfaces are key for organic electronics. Using a combination of scanning tunneling microscopy (STM) and non-contact atomic force microscopy (nc-AFM) we probe the structures of copper phthalocyanine (CuPc) on In$ _2$ O$ _3$ , a model for a prototypical transparent conductive oxide (TCO). These scanning-probe images allow the direct determination of the adsorption site and distortions of the molecules, which are corroborated by DFT calculations. Isolated CuPc molecules adsorb in a flat, slightly tilted geometry in three symmetry-equivalent configurations on the stoichiometric In$ _2$ O$ _3$ (111) surface. Increasing the coverage leads to densely-packed 1D chains oriented along $ \langle1\bar{1}0\rangle$ directions, which dissolve into a highly ordered (2$ \times$ 2) superstructure upon increasing the CuPc density to 3/4 per surface unit cell. At a coverage of one CuPc per surface unit cell, a densely packed (1$ \times$ 1) superstructure fully covers the surface. The molecules still assume the same site and orientation as before, but they partially overlap to accommodate the high packing density, leading to a bending of the molecules. These results are compared to the behavior of CoPc on In$ _2$ O$ _3$ (111). In summary, we demonstrate that a uniform first layer of metal-phthalocyanine molecules can be realized on the In$ _2$ O$ _3$ (111) surface when using the proper metal atom in the molecule.
Materials Science (cond-mat.mtrl-sci)
Large non-saturating Nernst thermopower and magnetoresistance in compensated semimetal ScSb
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-15 20:00 EDT
Antu Laha, Sarah Paone, Niraj Aryal, Qiang Li
Today, high-performance thermoelectric and thermomagnetic materials operating in the low-temperature regime, particularly below the boiling point of liquid nitrogen remain scarce. Most thermomagnetic materials reported to date exhibit a strong Nernst signal along specific crystallographic directions in their single-crystal form. However, their performance typically degrades significantly in the polycrystalline form. Here, we report an improved Nernst thermopower of $ \sim$ 128 $ \mu$ V/K at 30 K and 14 T in polycrystalline compensated semimetal ScSb, in comparison to that was observed in single crystal ScSb previously. The magnetic field dependence of Nernst thermopower shows a linear and non-saturating behavior up to 14 T. The maximum Nernst power factor reaches to $ \sim 240 \times 10^{-4}$ W m$ ^{-1}$ K$ ^{-2}$ and Nernst figure of merit reaches to $ \sim 11 \times 10^{-4}$ K$ ^{-1}$ . Polycrystalline ScSb also shows a large non-saturating magnetoresistance of $ \sim 940 %$ at 2 K and 14 T. These enhanced properties originate from better electron-hole compensation, as revealed by Hall resistivity measurements. The cubic symmetry and absence of anisotropy in ScSb allow its polycrystalline form to achieve similar enhanced thermomagnetic and electromagnetic performance comparable to that of the single crystal.
Materials Science (cond-mat.mtrl-sci)
Accepted for publication in Materials Today Physics
Unraveling Magneto-Phononic Coupling and Photoinduced Magnetic Control in Antiferromagnetic Kondo Semimetal CeBi
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-15 20:00 EDT
Xu-Chen Nie, Chen Zhang, Qi-Yi Wu, Hao Liu, Jie Pang, You-Guo Shi, Zhi-An Xu, Yan-Feng Guo, Ya-Hua Yuan, H. Y. Liu, Yu-Xia Duan, Jian-Qiao Meng
We report an ultrafast optical spectroscopy study on the coherent phonon dynamics in the topological semimetal CeBi and its nonmagnetic isostructural compound LaBi, revealing profound insights into their electronic and magnetic interactions. Both materials exhibit prominent $ A_{1g}$ longitudinal optical phonons with characteristic anharmonic temperature dependencies. However, in CeBi, the $ A_{1g}$ phonon frequency and amplitude show clear anomalies near its antiferromagnetic (AFM) ordering temperatures ($ T_{N1}$ $ \simeq$ 25 K and $ T_{N2}$ $ \simeq$ 12 K), which unequivocally demonstrate strong magneto-phononic coupling. Crucially, in the AFM state at 4 K, CeBi exhibits a pump fluence threshold of $ F_C$ $ \approx$ 44 $ \mu$ J/cm$ ^2$ , above which the rate of phonon softening accelerates and the amplitude increases sharply. This unique threshold, absent in paramagnetic CeBi and LaBi, points to a photoinduced, non-thermal quenching of the AFM order. Our findings establish coherent phonons as highly sensitive probes of intertwined orders in heavy fermion systems, highlighting the transformative potential of ultrafast pulses in dynamically controlling magnetic states in correlated electron materials and paving the way for the manipulation of emergent quantum phases.
Strongly Correlated Electrons (cond-mat.str-el)
6 pages,3 figures
Tunneling spin Hall effect induced by unconventional $p$-wave magnetism
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-15 20:00 EDT
We propose a tunneling spin Hall effect in a normal metal/$ p$ -wave magnet/superconductor junction. It is found that the Andreev reflection in the normal lead is spin-dependent and exhibits strong asymmetry with respect to the transverse momentum, giving rise to a pure transverse spin Hall current with zero net charge. The transverse spin conductance is analytically derived using the nonequilibrium Green’s function approach, revealing that the predicted spin Hall effect is governed by the direction of the Fermi surface splitting in the $ p$ -wave magnet. A finite transverse spin current with a large spin Hall angle arises when the line connecting the centers of the spin-split Fermi surfaces is perpendicular to the normal direction of the junction, which indicates a highly efficient charge-to-spin conversion, suggesting potential applications in spintronic devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
10 pages, 4 figures
Spin current generation driven by skyrmion dynamics under magnetic anisotropy and polarized microwaves
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-15 20:00 EDT
Seno Aji, Muhammad Anin Nabail Azhiim, Nur Ika Puji Ayu, Adam Badra Cahaya, Koichi Kusakabe, Muhammad Aziz Majidi
We have investigated the spin-current pumped by the skyrmion-host material with the lack of inversion symmetry through the microwave resonance process. The effects of magnetic anisotropy and polarized microwaves are examined by micromagnetic simulations. Our results reveal two distinct skyrmion phases, designated as SkX type-I and II, which emerge at low ($ K_z<0.1$ meV) and high ($ K_z>0.1$ meV) magnetic anisotropy constants, respectively, having different characteristics of spin excitations. The SkX type-I exhibits spin dynamics where the resonant frequency of the breathing mode is lying in between the clockwise and counterclockwise gyration modes of Bloch-type skyrmion at a very low anisotropy, and is crossing over the counterclockwise mode at $ K_z \sim 0.04$ meV. Meanwhile, the SkX type-II exhibits distinct spin excitations in which the clockwise mode is notably absent, while the counterclockwise modes exist at both low and high resonant frequencies. This suggests that the magnetic anisotropy plays an essential role in the spin dynamics. Furthermore, the resulting spin excitations induce spin currents with exotic features under the polarized microwaves. The spin currents induced, for instance, by low-lying in-plane excitations are strongly enhanced under the left-handed circularly polarized microwaves, but quenched by the right-handed circularly polarized microwaves regardless of the sign of the Dzyaloshinskii-Moriya interaction. These results may pave the way for understanding the non-trivial interplay between magnetic anisotropy and polarized microwaves in the generation of spin currents by a resonant process.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph), Computational Physics (physics.comp-ph)
8 pages, 8 figures
Influence of thermal noise on the field-driven dynamics of the non-collinear antiferromagnet Mn3Sn
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-15 20:00 EDT
Siyuan Qian, Ankit Shukla, Shaloo Rakheja
$ \mathrm{Mn_3Sn}(0\overline{1}\overline{1}0)[0001]$ experiences a tensile strain when grown epitaxially on $ \mathrm{MgO}(110)[001]$ , and thus the energy landscape changes from six-fold symmetry to two-fold symmetry. External magnetic field further breaks the symmetry and the \textcolor{black}{resulting energy landscape is sensitive to} the field orientation relative to the easy axis. \textcolor{black}{In the presence of thermal noise,} the relaxation of the magnetic octupole moment in \textcolor{black}{a strained Mn$ _3$ Sn film} is composed of four distinct escape processes involving the two saddle points and two equilibrium states in the energy landscape. Here, we apply harmonic transition-state theory to derive analytical expressions for the inter-well escape time and octupole moment relaxation time, both influenced by an external symmetry-breaking magnetic field and finite thermal noise in the intermediate-to-high damping regime. The analytical predictions are in strong agreement with comprehensive numerical simulations based on coupled LLG equations. The results presented here are crucial toward realizing Mn$ _3$ Sn’s applications in random number generation and probabilistic computing.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
15 pages, 10 figures
Time arrow in open-boundary one-dimensional stochastic dynamics
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-15 20:00 EDT
Chi-Lun Lee, Yu-Syuan Lin, Pik-Yin Lai
We consider the finite-timestep Brownian dynamics of a single particle confined in one dimension, with a nonuniform temperature profile. In such an open-boundary scenario, one cannot observe any net probability current in the nonequilibrium steady state (NESS). On the other hand, the nonequilibrium nature of this system is exhibited through the asymmetry in forward and backward transition probabilities, as is reported in this work through the stochastic simulation analysis and theoretical arguments. The irreversibility becomes prominent nearby the temperature interface. We propose that the observed irreversibility can be accounted for via a virtual-gyration scenario, while the collapse of virtual gyrations upon the one-dimensional coordinate leads to the absence of probability current.
Statistical Mechanics (cond-mat.stat-mech)
8 pages, 4 figures
Evidence for magnetoelastic coupling and chiral magnetic ground state in quasi-van der Waals tr-Cr${1.22}$Te${2}$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-15 20:00 EDT
S. M. Hossain, B. Rai, P. R. Baral, O. Zaharko, N. Kumar, A. K. Bera, M. Majumder
Trigonal tr-Cr$ _{1+\delta}$ Te$ _{2}$ is a well-known ferromagnetic material that has recently drawn much attention due to the discovery of zero-field skyrmion state, unusual anomalous Hall effect, topological Hall effect, and topological Nernst effect. This quasi-van der Waals (vdW) layered material with intercalated Cr atoms possesses many peculiar features that depend on the amount of Cr intercalation, although the microscopic magnetic ground state is still elusive. We reveal the structural and magnetic properties of tr-Cr$ _{1.22}$ Te$ _{2}$ by low-temperature x-ray diffraction, magnetization, temperature-dependent Raman spectroscopy, and single-crystal neutron diffraction studies. Magnetization measurements under small applied magnetic field indicate two successive magnetic transitions, one from a ferromagnetic (FM) state to an antiferromagnetic (AFM) state (T$ _\mathrm{C}=197$ K), and second from AFM to a paramagnetic state (T$ _\mathrm{N}=211$ K). The FM transition is sharp with a strong presence of magnetoelastic coupling, but is not accompanied by any structural phase transition. The magnetic structure obtained from zero-field single crystal neutron diffraction reveals that the Cr1 and Cr2 moments are ferromagnetically aligned along the c-axis, while the Cr3 and intercalated Cr4 atoms induce an AFM component in the ab-plane leading to an umbrella-like spin structure which possesses a finite spin chirality. The presence of a finite spin chirality is responsible for the observation of the topological Hall effect (THE).
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
14 pages, 7 figures
Lecture Notes on Quantum Many-Body Theory: A Pedagogical Introduction
New Submission | Other Condensed Matter (cond-mat.other) | 2025-07-15 20:00 EDT
Fabrizio Tafuri, Carmine Antonio Perroni, Giulio De Filippis
In these notes, we present a rigorous and self-contained introduction to the fundamental concepts and methods of quantum many-body theory. The text is designed to provide a solid theoretical foundation for the study of interacting quantum systems, combining clarity with mathematical precision. Core topics are developed systematically, with detailed derivations and comprehensive proofs that aim to make the material accessible to graduate students and beginning PhD students. Special attention is given to formal consistency and pedagogical structure, so as to guide the reader through both the conceptual and technical aspects of the subject. This work is intended as a reliable starting point for further exploration and research in modern quantum many-body physics.
Other Condensed Matter (cond-mat.other), Quantum Gases (cond-mat.quant-gas), Statistical Mechanics (cond-mat.stat-mech), Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
514 pages, around 60 figures. Draft of the Lecture notes for the course “Quantum Many-Body Theory”
A CLuP algorithm to practically achieve $\sim 0.76$ SK–model ground state free energy
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-07-15 20:00 EDT
We consider algorithmic determination of the $ n$ -dimensional Sherrington-Kirkpatrick (SK) spin glass model ground state free energy. It corresponds to a binary maximization of an indefinite quadratic form and under the \emph{worst case} principles of the classical NP complexity theory it is hard to approximate within a $ \log(n)^{const.}$ factor. On the other hand, the SK’s random nature allows (polynomial) spectral methods to \emph{typically} approach the optimum within a constant factor. Naturally one is left with the fundamental question: can the residual (constant) \emph{computational gap} be erased?
Following the success of \emph{Controlled Loosening-up} (CLuP) algorithms in planted models, we here devise a simple practical CLuP-SK algorithmic procedure for (non-planted) SK models. To analyze the \emph{typical} success of the algorithm we associate to it (random) CLuP-SK models. Further connecting to recent random processes studies [94,97], we characterize the models and CLuP-SK algorithm via fully lifted random duality theory (fl RDT) [98]. Moreover, running the algorithm we demonstrate that its performance is in an excellent agrement with theoretical predictions. In particular, already for $ n$ on the order of a few thousands CLuP-SK achieves $ \sim 0.76$ ground state free energy and remarkably closely approaches theoretical $ n\rightarrow\infty$ limit $ \approx 0.763$ . For all practical purposes, this renders computing SK model’s near ground state free energy as a \emph{typically} easy problem.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Information Theory (cs.IT), Optimization and Control (math.OC), Machine Learning (stat.ML)
Microscopic origin of shear bands in 2D amorphous solids from topological defects
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-15 20:00 EDT
Arabinda Bera, Debjyoti Majumdar, Timothy W. Sirk, Ido Regev, Alessio Zaccone
The formation of shear bands in amorphous solids such as glasses has remained an open question in our understanding of condensed matter and amorphous materials. Unlike in crystals, well-defined topological defects such as dislocations have been elusive due to the lack of a periodic ordered background at the atomic level. Recently, topological defects have been identified in the displacement field and in the eigenvectors of amorphous solids. Recent work has suggested that shear bands in amorphous solids coincide with an alignment of vortex-antivortex dipoles, with alternating topological charge +1/-1. Here we numerically confirm this hypothesis by means of well-controlled simulations in 2D. Surprisingly, we show that a chain of topological defects (TDs) pre-exists the shear band and is visible already in the non-affine displacement field of the elastic regime. This chain is activated into a flow band concomitantly with the disappearance and possibly annihilation of a dipole at a distance from the TDs chain. The possible underlying mechanism is reminiscent of a soliton-like rarefaction pulse remotely activated by dipole annihilation as observed in superfluid Bose-Einstein condensates.
Soft Condensed Matter (cond-mat.soft), Disordered Systems and Neural Networks (cond-mat.dis-nn), Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other), Applied Physics (physics.app-ph)
Quantum metric-based optical selection rules
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-15 20:00 EDT
The optical selection rules dictate symmetry-allowed/forbidden transitions, playing a decisive role in engineering exciton quantum states and designing optoelectronic devices. While both the real (quantum metric) and imaginary (Berry curvature) parts of quantum geometry contribute to optical transitions, the conventional theory of optical selection rules in solids incorporates only Berry curvature. Here, we propose quantum metric-based optical selection rules. We unveil a universal quantum metric-oscillator strength correspondence for linear polarization of light and establish valley-contrasted optical selection rules that lock orthogonal linear polarizations to distinct valleys. Tight-binding and first-principles calculations confirm our theory in two models (altermagnet and Kane-Mele) and monolayer $ d$ -wave altermagnet $ \mathrm{V_2SeSO}$ . This work provides a quantum metric paradigm for valley-based spintronic and optoelectronic applications.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Computational Physics (physics.comp-ph), Optics (physics.optics)
$WSe_2$ Monolayers Grown by Molecular Beam Epitaxy on hBN
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-15 20:00 EDT
Julia Kucharek, Mateusz Raczyński, Rafał Bożek, Anna Kaleta, Bogusława Kurowska, Marta Bilska, Sławomir Kret, Takashi Taniguchi, Kenji Watanabe, Piotr Kossacki, Mateusz Goryca, Wojciech Pacuski
A three-step process was developed for growing high-quality, optically uniform WSe2 monolayers by molecular beam epitaxy (MBE) with advantage of using hexagonal boron nitride (hBN). The process was optimized to maximize the efficiency of photoluminescence and promote formation of hexagonal WSe2 domains. Atomic force microscopy (AFM) was employed to estimate the dispersion of WSe2 hexagonal domains orientation. Monolayer character of the film was identified using optical methods and verified with high-resolution transmission electron microscopy (TEM) cross-section. Temperature-and-magnetic-field-dependent studies revealed the behaviour of exciton complexes to be analogical to that of exfoliated counterparts. Direct growth on hBN combined with uniform optical response proves this WSe2 superior to mechanically exfoliated WSe2 in terms of convenience of use and reproducibility. Provided results establish a significant progress in optical quality of epitaxially grown transition metal dichalcogenides (TMDs) monolayers and fabrication of large-scale functional devices.
Materials Science (cond-mat.mtrl-sci)
Article and SI, 18 pages in total, 10 figures in total
Spin-triplet pairing instability in a two-dimensional repulsive Hubbard model
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-07-15 20:00 EDT
Xing-Can Liu, Yu-Feng Song, Yuan-Yao He, Tao Ying, Xueru Zhang
The search for superconductivity with unconventional pairing symmetry has been a central focus in the study of strongly correlated electron systems. In this work, we report a numerically exact study of the spin-triplet pairing in a two-dimensional Hubbard model with repulsive interactions, employing Determinant Quantum Monte Carlo method. The model includes next-nearest-neighbor and third-nearest-neighbor hopping terms, and maintains spin balance. By tuning the fermion filling close to a type-II van Hove singularity (vHs) in the model, we numerically investigate the ordering tendencies of several possible pairing channels with different symmetries. Our numerical results provide clear evidence for the spin-triplet $ p$ -wave pairing instability approaching low temperatures, as revealed by the vertex contribution to the pairing susceptibility. This signature becomes increasingly pronounced as the interaction strength increases in the weak to intermediate regime. We further find that, near the type-II vHs, the dominant spin-spin correlations in the system are ferromagnetic, suggesting its close relation to the spin-triplet pairing instability. Our findings offer a reliable approach to realize the spin-triplet $ p$ -wave superfluidity in the repulsive Hubbard model, from an unbiased numerical perspective.
Quantum Gases (cond-mat.quant-gas)
Quantum Anomalous Hall Effect in Flat Bands with Paramagnetism
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-15 20:00 EDT
Yedi Shen, Sanyi You, Zhenhua Qiao, Qian Niu
Quantum anomalous Hall effect has been widely explored in both ferromagnetic and antiferromagnetic systems. Here, we propose an interaction-driven paramagnetic quantum anomalous Hall effect emerging in the Fermion-Hubbard model on a dice lattice with weak spin-orbit coupling. Based on exact diagonalization calculations, the time-reversal symmetry breaking in the ground state is evidenced by nonuniform loop currents between nearest-neighbor sites. The many-body ground state possesses a Chern number of $ \mathcal{C}=2$ or $ 6$ , and strong correlation effects in the half-filled flat bands lead to a well-defined first excitation gap and a clear insulating gap, ensuring the robustness against thermal fluctuations and external perturbations. The interplay between spin-orbit coupling and Hubbard interaction allows tunability of various magnetic ground states, generating a rich phase diagram with competing ferromagnetic, antiferromagnetic, and paramagnetic orders.
Strongly Correlated Electrons (cond-mat.str-el)
First-principles design for strain-tunable exciton dynamics in 2D materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-15 20:00 EDT
Amir Kleiner, Sivan Refaely-Abramson
Controlling exciton motion in two-dimensional semiconductors is key to unlocking new optoelectronic and straintronic functionalities. Monolayer transition metal dichalcogenides (TMDs), with their tightly bound excitons, offer an ideal platform for such control due to their strong sensitivity to local strain. Here we present an ab initio framework for modeling exciton dynamics in inhomogeneously strained WS2, combining excitonic band structures derived from first principles with a semiclassical transport model operating in both real and momentum space. By analyzing idealized strain patterns, we reveal how excitons undergo drift, diffusion, and confinement without invoking empirical parameters. Our results uncover regimes of super-ballistic propagation and negative effective diffusion, governed entirely by the strain landscape. This work provides microscopic insight into strain-tunable exciton behavior and establishes design principles for engineering exciton flow in two-dimensional materials.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Expansion dynamics of strongly correlated lattice bosons
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-07-15 20:00 EDT
Julian Schwingel, Michael Turaev, Johann Kroha, Sayak Ray
We study the spatio-temporal dynamics of interacting bosons on a two-dimensional Hubbard lattice in the strongly interacting regime, taking into account the dynamics of condensate amplitude as well as the direct transport of non-condensed fluctuations. To that end we develop a selfconsistent density-matrix approach which goes beyond the standard Gutzwiller mean-field theory. Starting from the Liouville-von-Neumann equation we derive a quantum master equation for the time evolution of the system’s local density matrix at each lattice site, with a dynamical bath that represents the rest of the system. We apply this method to the expansion dynamics of an initially prepared cloud of interacting bosons in an optical lattice. We observe a ballistic expansion of the condensate, as expected, followed by slow, diffusive transport of the normal bosons. We discuss, in particular, the robustness of the Mott insulator phase as well as its melting due to incoherent transport. The method should be applicable to various models of lattice bosons in the strongly correlated regime.
Quantum Gases (cond-mat.quant-gas), Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
Deciphering the Scattering of Polydisperse Hard Spheres using Deep Learning
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-15 20:00 EDT
Lijie Ding, Chi-Huan Tung, Wei-Ren Chen, Changwoo Do
We introduce a deep learning approach for analyzing the scattering function of the polydisperse hard spheres system. We use a variational autoencoder-based neural network to learn the bidirectional mapping between the scattering function and the system parameters including the volume fraction and polydispersity. Such that the trained model serves both as a generator that produce scattering function from the system parameters, and an inferrer that extract system parameters from the scattering function. We first generate a scattering dataset by carrying out molecular dynamics simulation of the polydisperse hard spheres modeled by the truncated-shifted Lennard-Jones model, then analyze the scattering function dataset using singular value decomposition to confirm the feasibility of dimensional compression. Then we split the dataset into training and testing set and train our neural network on the training set only. Our generator model produce scattering function with significant higher accuracy comparing to the traditional Percus-Yevick approximation and $ \beta$ correction, and the inferrer model can extract the volume fraction and polydispersity with much higher accuracy than traditional model functions.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
9 pages, 11 figures
Topological in-gap chiral edge states in superconducting Haldane model with spin-orbit coupling
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-15 20:00 EDT
Topological superconductivity is currently one of the prime interests, given the properties of its exotic nature of chiral edge states. A broken time-reversal symmetry (TRS) is an essential ingredient in the recipe of a chiral edge state. The Haldane model is one of the many factors that can break TRS in a system. Thus, we explore the possibility of topological superconductivity in the Haldane model under the influence of a conventional superconductor. The edge states originating from such recipes mostly remain outside the superconducting gap. Contrary to this, in the presence of spin-orbit coupling, the edge modes lie within the superconducting gap, and can lead to a gapless state for some range of parameters. Moreover, we use band inversion and projection on the real-space lattice to confirm the topological and chiral nature of the obtained edge states.
Superconductivity (cond-mat.supr-con)
12 pages, 8 figures
Nanoscale friction of manganite superlattice films controlled by layer thickness and fluorine content
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-15 20:00 EDT
Niklas A. Weber, Miru Lee, Florian Schönewald, Leonard Schüler, Vasily Moshnyaga, Matthias Krüger, Cynthia A. Volkert
We investigate nanoscale friction in [LaMnO3]m/[SrMnO3]n superlattice films using lateral force microscopy, focusing on the effects of fluorine doping and top-layer thickness. For all samples, friction forces scale linearly with the sum of the applied normal and adhesion forces. While friction forces vary spatially due to local adhesion fluctuations, the friction coefficient remains position independent for each specimen. It is, however, systematically influenced by fluorine concentration and top-layer thickness. Our data indicates that frictional energy dissipation extends up to 5 nm beneath the surface, demonstrating a clear dependence on subsurface structure. We attribute this to viscoelastic dissipation within the stress field and evanescent waves generated by the sliding tip, which can quantitatively account for the observed friction coefficients. These results show that, once adhesion is properly accounted for, the friction coefficient is a reproducible material property that can be tuned via controlled modifications to surface and subsurface layers.
Materials Science (cond-mat.mtrl-sci)
19 pages, 4 figures
Lyapunov formulation of band theory for disordered non-Hermitian systems
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-07-15 20:00 EDT
Non-Bloch band theory serves as a cornerstone for understanding intriguing non-Hermitian phenomena, such as the skin effect and extreme spectral sensitivity to boundary conditions. Yet this theory hinges on translational symmetry and thus breaks down in disordered systems. Here, we develop a real-space Lyapunov formulation of band theory that governs the spectra and eigenstates of disordered non-Hermitian systems. This framework yields universal non-Hermitian Thouless relations linking spectral density and localization to Lyapunov exponents under different boundary conditions. We further identify an exact topological criterion: skin modes and Anderson-localized modes correspond to nonzero and zero winding numbers, respectively, revealing the topological nature of the skin-Anderson transition. This transition is dictated by an essential Lyapunov exponent and gives rise to novel unidirectional critical states. Our formulation provides a unified and exact description of spectra and localization in generic one-dimensional non-Hermitian systems without translational symmetry, offering new insights into the interplay among non-Hermiticity, disorder, and topology.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
8+6 pages, 5+1 figures
Variational Formulation of Local Molecular Field Theory
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-15 20:00 EDT
In this note, we show that the Local Molecular Field theory of Weeks et. al. can be re-derived as an extremum problem for an approximate Helmholtz free energy. Using the resulting free energy as a classical, fluid density functional yields an implicit solvent method identical in form to the Molecular Density Functional theory of Borgis et. al., but with an explicit formula for the ‘ideal’ free energy term. This new expression for the ideal free energy term can be computed from all-atom molecular dynamics of a solvent with only short-range interactions. The key hypothesis required to make the theory valid is that all smooth (and hence long-range) energy functions obey Gaussian statistics. This is essentially a random phase approximation for perturbations from a short-range only, ‘reference,’ fluid. This single hypothesis is enough to prove that the self-consistent LMF procedure minimizes a novel density functional whose ‘ideal’ free energy is the molecular system under a specific, reference Hamiltonian, as opposed to the non-interacting gas of conventional density functionals. Implementation of this new functional into existing software should be straightforward and robust.
Soft Condensed Matter (cond-mat.soft)
5 pages, 1 figure
Rare Events, Many Searchers, and Fast Target Reaching in a Finite Domain
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-15 20:00 EDT
Elisabetta Ellettari, Giacomo Nasuti, Alberto Bassanoni, Alessandro Vezzani, Raffaella Burioni
Finding a target in a complex environment is a fundamental challenge in nature, from chemical reactions to sperm reaching an egg. An effective strategy to reduce the time needed to reach a target is to deploy many searchers, increasing the likelihood that at least one will succeed by using the statistics of rare events. When the underlying stochastic process involves broadly distributed step sizes, rare long jumps dominate the dynamics, making the use of multiple searchers particularly powerful. We investigate the statistics of extreme events for the mean first passage time in a system of $ N$ independent walkers moving with jumps distributed according to a power law, where target-reaching is governed by single, large fluctuations. We show that the mean first passage time of the fastest walker scales as $ \langle \tau_N \rangle \sim 1/N$ , representing a dramatic speed-up compared to classical Brownian search strategies. From this, we derive a scaling law relating the number of walkers required to reach a target within a given time to the size $ X$ of the search region. As an application, we model biological fertilization, predicting how the optimal number of spermatozoa scales with uterus size across species. Our predictions match empirical data, suggesting that evolution may have exploited rare-event dynamics and broadly distributed motion to optimize reproductive success. This theory applies broadly to any population of searchers operating within a region of size $ X$ , providing a universal framework for efficient search in disordered or high-dimensional environments.
Statistical Mechanics (cond-mat.stat-mech)
16 pages, 6 figures
Intermediate Interaction Strategies for Collective Behavior
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-15 20:00 EDT
From bird flocks and fish schools to migrating cell sheets, collective motion is a ubiquitous biological phenomenon that inspires quantitative modeling through self-propelled particle (SPP) frameworks. Conventional SPP models prescribe either distance-based (metric) or rank-based (topological) interactions; however, empirical studies indicate that real groups may blend both types of interaction. Motivated by this graded perception, we introduce a new three-dimensional SPP model in which metric and topological alignments act simultaneously and are weighted by a single tunable mixing parameter called the interaction parameter. Large-scale simulations spanning a wide ranges of interaction parameters and densities revealed rich dynamics. Even when the global order parameter is low, cluster-level analysis with HDBSCAN shows that particles self-organize into several spatially distinct but internally well-aligned sub-flocks, exposing a hidden layer of order. Most importantly, an intermediate balance in which metric and topological cues contribute almost equally maximizes the global order parameter and markedly improves robustness to density variations. Numerical experiments supported by linear stability analysis demonstrate that activating metric and topological interactions in concert bridges the traditional modeling dichotomy and furnishes a more adaptive and resilient framework for collective motion. Therefore, the proposed model therefore provides a versatile platform for exploring mixed-interaction effects in biological and engineered multi-agent systems.
Statistical Mechanics (cond-mat.stat-mech)
13 pages, 7 figures
Magnon Correlation Enables Spin Injection, Dephasing, and Transport in Canted Antiferromagnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-15 20:00 EDT
Thermal and electrical injection and transport of magnon spins in magnetic insulators is conventionally understood by the non-equilibrium population of magnons. However, this view is challenged by several recent experiments in noncollinear antiferromagnets, which urge a thorough theoretical investigation at the fundamental level. We find that the magnon spin in antiferromagnets is described by a matrix, so even when the diagonal terms – spins carried by population – vanish, the off-diagonal correlations transmit magnon spins. Our quantum theory shows that a net spin-flip of electrons in adjacent conductors creates quantum coherence between magnon states, which transports magnon spins in canted antiferromagnets, even without a definite phase difference between magnon modes in the incoherent process. It reveals that the pumped magnon correlation is not conserved due to an intrinsic spin torque, which causes dephasing and strong spatial spin oscillations during transport; both are enhanced by magnetic fields. Spin transfer to proximity conductors can cause extrinsic dephasing, which suppresses spin oscillations and thereby gates spin transport.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
7 pages, 4 figures
Magnetic control of nonlinear transport induced by the quantum metric
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-15 20:00 EDT
Xu Chen, Mingbo Dou, Qin Zhang, Xianjie Wang, M. Ye. Zhuravlev, A. V. Nikolaev, L. L. Tao
The quantum geometry plays a crucial role in the nonlinear transport of quantum materials. Here, we use the Boltzmann transport formalism to study the magnetic control of nonlinear transport induced by the quantum metric in two-dimensional systems with different types of spin-orbit coupling (SOC). It is shown that the nonlinear conductivity is strongly dependent on the direction of a field and reveals significant spatial anisotropy. Moreover, the field-direction dependent relations are distinct for different SOCs. In addition, it is demonstrated that the contributions from the quantum metric and Drude mechanism are distinguishable due to their opposite signs or distinct anisotropy relations. We further derive the analytical formulas for the anisotropic nonlinear conductivity, in exact agreement with numerical results. Our work shines more light on the interplay between the nonlinear transport and quantum geometry.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Perfect Superconducting Diode and Supercurrent Range Controller
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-15 20:00 EDT
Diodes have a nonreciprocal voltage versus current relationship, produced by breaking the space and time reversal symmetry. However, developing high-end superconducting computers requires a superconducting analogue of the traditional semiconductor diode. Such a superconducting diode exhibits non-reciprocity, or a high asymmetry in its critical currents. We present a model of a perfect superconducting diode based on a superconducting quantum interference device made with multiple superconducting nanowires (MW-SQUID). The superconducting condensate in the nanowires is assumed to obey a linear current-phase relationship (CPR). The diode predicted by our model has a large positive critical current, while the negative critical current can be made exactly zero. Thus achieved 100% diode efficiency ($ \eta = 1$ ) remains stable against small changes of the magnetic field. Another important result is that under certain and quite broad conditions such devices can act as supercurrent range controllers. In such device a supercurrent can flow with zero voltage applied, but only if the supercurrent is contained in some narrow, adjustable range, which excludes zero current.
Superconductivity (cond-mat.supr-con)
6 pages, 5 figures
Electronic and magnetic ground states of {112} grain boundary in graphene in the extended Hubbard model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-15 20:00 EDT
Sishir Jana, Dayasindhu Dey, Manoranjan Kumar, S. Ramasesha, Rajamani Raghunathan
We study the ground state phase diagram of the extended Hubbard model in a half-filled 5/7 skewed ladder, which is topologically equivalent to a {112} grain boundary in graphene and related systems. Using the mean-field method, we identify various electronic and magnetic phases in the U-V plane, by calculating the site charge and spin densities. The electronic phases include partially charge-ordered metal or insulator, and fully charge-ordered insulator. The different magnetic phases of the model are non-magnet, spin density wave, spin split compensated ferrimagnet or partial antiferromagnet. Analysis of the electronic band structure reveals that the partially charge-ordered compensated ferrimagnetic phase exhibits spin polarisation, which can be quite interesting for spintronics applications. We also compute the polarisation as a function of $ U$ using the Berry phase formalism and show that the system exhibits multiferroicity with coexisting compensated ferrimagnetic spin order alongside electronic polarisations.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Magnon-induced transparency of a disordered antiferromagnetic Josephson junction
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-15 20:00 EDT
We considered a planar Josephson junction which is composed of two s-wave superconducting contacts deposited on the top of a thin antiferromagnetic (AFM) disordered metal film. In such a system noticeable Josephson currents may be observed, if contacts are just nanometers away from each other. It is shown that the excitation of AFM by magnons results in a strong enhancement of the stationary current through much longer junctions, whose length may be comparable to the coherence length of superconducting correlations in a nonmagnetic metal. Such a current is calculated at the weak tunneling amplitude of electrons between superconducting contacts and AFM. The problem is considered for nonequilibrium Green functions in the second-order perturbation theory with respect to the electron-magnon interaction. A spin-orbit torque oscillator was taken as a possible source of long-wavelength classic magnetic waves. This work predicts a strong effect of magnons on superconducting proximity effect in AFM, with promising applications in superconducting spintronics.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
5+6 pages, 5 figures
Unlocking Altermagnetism in Antiferromagnetic 2D Films via Adsorption
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-15 20:00 EDT
Dong Liu, Sike Zeng, Ji-Hai Liao, Yu-Jun Zhao
Altermagnets, characterized by zero net magnetization and momentum-dependent spin splitting, have recently garnered significant attention due to their potential applications in a variety of fields. Here, we propose a symmetry-engineering strategy to unlock altermagnetism in two dimensional (2D) antiferromagnetic systems via surface adsorption of atoms or molecules. By employing spin group theory, we systematically demonstrate that selectively breaking symmetry operations, specifically those protecting spin degeneracy in momentum space, enables the emergence of nonrelativistic spin-split electronic states. Meanwhile, preserving rotation or mirror symmetries connecting opposite sublattices ensures zero net magnetization. Through a comprehensive classification of all symmetry operations across 80 layer groups, we identify 63 antiferromagnetic spin point groups (SPGs) describing 2D materials and further isolate 15 groups that can host altermagnetic characteristics through surface adsorption. Exemplified with monolayer antiferromagnetic VPS_3 and MnPSe_3, we show that oxygen adsorption on VPS_3 and NH_3 adsorption on MnPSe_3 selectively disrupt PT symmetry while retaining the [C2||m] symmetry. This engineered symmetry reduction induces pronounced spin splitting in their band structures without spin-orbit coupling, as confirmed by first-principles calculations. Furthermore, adsorption energy analysis and thermal stability phase diagrams under varying coverage regimes reveal optimal configurations for experimental feasibility. Our work establishes a universal symmetry-engineering framework to expand the family of altermagnetic materials, offering a versatile pathway to tailor spin-split functionalities in two-dimensional antiferromagnets for advanced quantum applications.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Quantum interference among vortex bound states in superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-15 20:00 EDT
Yi-Ming Fu, Da Wang, Qiang-Hua Wang
In a recent experiment (Hou et al Phys. Rev. X 15, 011027), a new type of necklace-like vortex bound state (VBS) was observed and attributed to disorder induced interference among different Caroli-de Gennes-Matricon (CdGM) states within one single vortex. In this work, we further investigate the possibilities of quantum interference among the CdGM states from different vortices in clean superconductors, which may become significant near the upper critical field. We find a series of interference patterns in the local density of states (LDOS) due to the overlap between spatially separated individual CdGM states. On a vortex lattice, the interference can also lead to a necklace-like LDOS, hence, providing an alternative and intrinsic mechanism to observe the novel necklace-like, or other spatially modulated VBS more generally, in experiments. These results can be understood quite well within an effective tight-binding model constructed from the individual CdGM states, and can be checked in future experiments.
Superconductivity (cond-mat.supr-con)
5 pages, 3 figures
New J. Phys. 27 073502 (2025)
Correlating synthesis, structure and thermal stability of CuBi nanowires for spintronic applications by electron microscopy and in situ scattering methods
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-15 20:00 EDT
Alejandra Guedeja-Marrón, Henrik Lyder Andersen, Gabriel Sánchez-Santolino, Lunjie Zeng, Alok Ranjan, Inés García-Manuz, François Fauth, Catherine Dejoie, Eva Olsson, Paolo Perna, Maria Varela, Lucas Pérez, Matilde Saura-Múzquiz
Bi-doped copper (Cu1-xBix) nanowires (NWs), promising candidates for spintronic applications due to their potential for a giant spin Hall effect (SHE), were synthesized and their structural properties and thermal stability were investigated. Using template-assisted electrodeposition, Cu1-xBix nanowires with varying bismuth (Bi) content (x=0, 2, 4, and 7%) and different crystalline domain sizes were fabricated. Structural analysis by advanced electron microscopy and X-ray scattering techniques revealed the influence of synthesis conditions on the resulting NW crystal structure and microstructure, including Bi localization (within the lattice or in the grain boundaries), crystallite domain dimensions, and lattice distortions. While NWs with larger crystalline domains allow homogeneous Bi incorporation into the Cu lattice, NWs with smaller crystalline domains exhibit noticeable Bi accumulation at grain boundaries. The thermal stability of the NWs was examined using variable temperature X-ray diffraction and total scattering. Upon heating, lattice distortions consistent with Bi diffusion out of the Cu lattice were observed, with subsequent crystallization of rhombohedral metallic Bi upon cooling. These findings establish a foundation for optimizing the SHE performance of Cu1-xBix nanowires for spintronic devices by correlating synthesis parameters with microstructural features and thermal behavior.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph)
45 pages, 9 figures
How to Fix Silver for Plasmonics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-15 20:00 EDT
Björn Ewald, Leo Siebigs, Cheng Zhang, Jonas Graf, Achyut Tiwari, Maximilian Rödel, Sebastian Hammer, Vladimir Stepanenko, Frank Würthner, Bruno Gompf, Bert Hecht, Jens Pflaum
Silver (Ag) is considered an ideal material for plasmonic applications in the visible wavelength regime due to its superior optical properties, but its use is limited by the poor chemical stability and structural quality of thermally evaporated thin films and resulting nanostructures. In this study, we present a simple approach to enhance the structural and optical quality as well as the chemical stability of Ag thin films by alloying with gold (Au) through thermal co-evaporation. We investigate Ag$ _{100-x}$ Au$ _x$ thin films with Au contents ranging from 5 to 20 at% analyzing their surface morphology, crystallite structure, optical properties, and chemical stability. Our results show that low Au concentrations significantly reduce the roughness of co-evaporated thin films (down to 0.4 nm RMS), and significantly enhance the resistance to oxidation, while maintaining a defined crystallite growth. Importantly, these improvements are achieved without the need for template stripping, metallic wetting layers, or epitaxial substrates, enabling direct deposition on glass. Among the compositions studied, Ag$ _{95}$ Au$ _5$ thin films exhibit the highest chemical stability, lowest optical losses in the visible spectral range, and excellent plasmonic properties even outcompeting pure Ag. As a proof-of-concept, we fabricate high-quality Ag$ _{95}$ Au$ _5$ optical antennas that exhibit long-term durability under ambient conditions. Our approach provides a practical solution to overcome the limitations of Ag for plasmonic device applications.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph), Optics (physics.optics)
Leakage at interfaces: a comprehensive study based on Persson contact mechanics theory
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-15 20:00 EDT
R. Xu, L. Gil, J. Singer, L. Gontard, W. Leverd, B.N.J. Persson
We present a comprehensive study of gas leakage at interfaces based on Persson contact mechanics theory. A prototype syringe system consisting of a rubber stopper and a glass barrel is selected, where surface roughness is characterized using measurements from stylus profilometry and atomic force microscopy, and contact pressure distributions are obtained from Finite Element Method (FEM) calculations. Leakage prediction is performed using Multiscale Contact Mechanics (MCM) software. The predicted results show good agreement with experimental measurements under controlled dry conditions. Sensitivity analyses indicate that small variations in elastic modulus and contact pressure can significantly influence leakage, particularly near the percolation threshold. This work provides a generalized and validated framework for leakage prediction and offers practical guidance for the design of sealing systems in pharmaceutical and engineering applications.
Soft Condensed Matter (cond-mat.soft), Classical Physics (physics.class-ph)
Pseudogap in the lightly hole-doped triangular-lattice moiré Hubbard model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-15 20:00 EDT
V. I. Kuz’min, M. A. Visotin, S. G. Ovchinnikov
The electronic structure of the lightly hole-doped triangular-lattice moiré Hubbard model is studied within cluster perturbation theory (CPT) using 13-site clusters for a fixed doping concentration $ p=1/13$ varying the Coulomb parameter $ U$ and the hopping phase parameter $ \phi$ related to the spin-orbital interaction. We have also developed a rather simple generalized mean-field approximation (GMFA) containing the amplitude of the spin correlations as a free parameter to fit the CPT this http URL evolution of the Fermi surface and the pseudogap with the parameters $ \phi$ and $ U$ is explained from the viewpoint of the short-range magnetic order. The geometric frustration and the additional model parameter related to the spin-orbital interaction result in a more rich physics of the pseudogap state compared to the case of a more conventional square lattice.
Strongly Correlated Electrons (cond-mat.str-el)
The Origin of the Gauge Theories of Glassy Systems
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-15 20:00 EDT
The analytical model of a glass-forming system is formulated within the formalism analogous to gauge theory constructions in quantum field theory. This work explores the scope of the proposed approach and investigates the equilibrium behavior of the model under the mean-field approximation. The analysis reveals three possible equilibrium scenarios, only one of which exhibits strong glass-forming ability. Additionally, an upper limit for the initial temperature is identified, beyond which quenching into the glassy state becomes impossible.
Statistical Mechanics (cond-mat.stat-mech), Disordered Systems and Neural Networks (cond-mat.dis-nn), Materials Science (cond-mat.mtrl-sci)
Nonequilibrium magnetic dynamics of the two-component Bose-Hubbard model
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-07-15 20:00 EDT
Hui Tan, Jianmin Yuan, Yongqiang Li
A central challenge in strongly interacting many-body systems is understanding the far-from-equilibrium dynamics. Here, we study the many-body magnetic dynamics of the two-component Bose-Hubbard model by developing a two-component extension of nonequilibrium bosonic dynamical mean-field theory. Using this numerical method, we uncover rich quantum spin dynamics via inter-species interaction quenches. A sudden ramp-up of interactions induces slow thermalization, leading to a long-lived metastable state, whereas quenching to weak interactions results in rapid thermal equilibrium, featuring a two-step relaxation behavior through distinct exponential decays. Furthermore, under periodic modulation of the inter-species interactions, emergent Floquet dynamics drives a transition from a magnetic to an unordered phase.
Quantum Gases (cond-mat.quant-gas)
Vertically Coupled Double Quantum Dots Connected In Parallel
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-15 20:00 EDT
Shinichi Amaha, Tsuyoshi Hatano, Takashi Nakajima, Seigo Tarucha
We report charge transport measurements in a ring-shaped quadruple quantum dot system, composed of two vertically coupled double quantum dots connected in parallel. The vertical coupling introduces an isospin degree of freedom tied to the layer index, and the parallel configuration enables independent access to each quantum dot pair. This design allows us to observe Coulomb diamonds and evaluate the interlayer energy offset. By extending this platform to triangular and hexagonal artificial lattices, we explore correlation effects such as isospin frustration. These results highlight the system’s potential for studying interaction-driven quantum phases.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Study of surface roughness modulation on the adhesion behavior of PDMS elastomer
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-15 20:00 EDT
Susheel Kumar, Krishnacharya Khare, Manjesh K. Singh
Adhesion control at the interface of two surfaces is crucial in various applications, including the design of micro- and nanodevices such as microfluidic devices, triboelectric nanogenerators, biochips, and electronic sensors. Several factors influence adhesion, including sample preparation, surface energy, mechanical properties such as modulus of elasticity, and surface texture or roughness. This study specifically investigates the effect of surface roughness on the adhesion behavior of the elastomer polydimethylsiloxane (PDMS), focusing on a complementary interface with identical roughness. To create surface roughness, sandpapers with grit sizes ranging from N = 120 to N = 2000 were used during the molding process. The surface roughness of the PDMS elastomer was then characterized using a stylus profilometer. Interfacial adhesion was evaluated through wedge test experiments, which enabled the analysis of the relationship between surface roughness, work of adhesion, and equilibrium crack length. Furthermore, the study also explores the correlation between the real area of contact and the work of adhesion.
Soft Condensed Matter (cond-mat.soft)
14 pages, 10 figures
Quantum Hall-like effect for neutral particles with magnetic dipole moments in a quantum dot
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-15 20:00 EDT
Carlos Magno O. Pereira, Edilberto O. Silva
We predict a new class of quantum Hall phenomena in completely neutral systems, demonstrating that the interplay between radial electric fields and dipole moments induces exact $ e^2/h$ quantization without the need for Landau levels or external magnetic fields. Contrary to conventional wisdom, our theory reveals that: (i) the singularity of line charges does not destroy topological protection, (ii) spin-control of quantization emerges from boundary conditions alone, and (iii) the effect persists up to 25 K, surpassing typical neutral systems. These findings establish electric field engineering as a viable route to topological matter beyond magnetic paradigms.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
8 pages, 7 figures, 2 tables
On-the-fly machine learning-augmented constrained AIMD to design new routes from glassy carbon to quenchable amorphous diamond with low pressure and temperature
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-15 20:00 EDT
Meng-Qi Cheng, Wei-Dong Luo, Hong Sun
Recent advances in machine learning have enabled large-scale atomic simulations with first-principles accuracy, allowing precise modeling of disordered materials such as glassy carbon (GC). However, conventional ab initio molecular dynamics (AIMD) cannot effectively capture anisotropic stress effects, which are believed to play a key role in the transformation of GC into amorphous diamond under extreme conditions. In this work, we present an on-the-fly machine learning-augmented constrained AIMD (ML-augmented CAIMD) approach by modifying VASP 6.3.2. Our simulations not only reproduce major experimental features of GC but also provide restrictive synthesis conditions and microscopic insights. We show that GC exhibits unexpectedly high plasticity, with its compressive and shear strengths enhanced by large strains. Under pressure, increasing annealing temperature promotes the formation of quenchable amorphous diamond via enhanced sp3 preservation, but this trend reverses above 2900 K due to thermal graphitization. Under non-hydrostatic compression, GC transforms into a superhard structure sustaining large stress differences, which sharply increase when confining pressure exceeds 40 GPa. Finally, severe rotational shear at 30 GPa induces sp3 fractions up to 80 percent at 300 to 1000 K. A hardened amorphous carbon retaining 64 percent sp3 content is achieved by decompression at 300 K, marking the lowest pressure-temperature route ever predicted. Our ML-augmented CAIMD provides a general framework for modeling structural transformations in disordered materials under anisotropic stresses.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
16 pages, 10 figures, 2 tables, and 6 pages of supplementary materials
A Novel Surface-confined Spiral State With The Double Period In The Cubic Chiral Helimagnet Cu$_2$OSeO$_3$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-15 20:00 EDT
Priya R. Baral, Oleg I. Utesov, Samuel H. Moody, Matthew T. Littlehales, Pierluigi Gargiani, Manuel Valvidares, Robert Cubitt, Nina-Juliane Steinke, Chen Luo, Florin Radu, Arnaud Magrez, Jonathan S. White, Victor Ukleev
The chiral magnetoelectric insulator Cu$ _2$ OSeO$ _3$ hosts a rich and anisotropic magnetic phase diagram that includes helical, conical, field-polarized, tilted conical, and skyrmion lattice phases. Using resonant elastic x-ray scattering (REXS), we uncover a new spiral state confined to the surface of Cu$ _2$ OSeO$ _3$ . This surface-confined spiral state (SSS) displays a real-space pitch of $ \sim$ 120 nm, which remarkably is twice the length of the incommensurate structures observed to-date in Cu$ _2$ OSeO$ _3$ . The SSS phase emerges at temperatures below 30~K when the magnetic field is applied near the $ \langle110\rangle$ crystallographic axis. Its surface localization is demonstrated through a combination of REXS in reflection and transmission geometries, with complementary small-angle neutron scattering measurements suggesting its absence from the bulk. We attribute the stabilization of the SSS to competing anisotropic interactions at the crystal surface. The discovery of a robust, surface-confined spiral paves the way for engineering energy-efficient, nanoscale spin-texture platforms for next-generation devices.
Strongly Correlated Electrons (cond-mat.str-el)
8 pages, 4 figures
Navigating the Evolution of Two-dimensional Carbon Nitride Research: Integrating Machine Learning into Conventional Approaches
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-15 20:00 EDT
Deep Mondal, Sujoy Datta, Debnarayan Jana
Carbon nitride research has reached a promising point in today’s research endeavours with diverse applications including photocatalysis, energy storage, and sensing due to their unique electronic and structural properties. Recent advances in machine learning (ML) have opened new avenues for exploring and optimizing the potential of these materials. This study presents a comprehensive review of the integration of ML techniques in carbon nitride research with an introduction to CN classifications and recent advancements. We discuss the methodologies employed, such as supervised learning, unsupervised learning, and reinforcement learning, in predicting material properties, optimizing synthesis conditions, and enhancing performance metrics. Key findings indicate that ML algorithms can significantly reduce experimental trial-and-error, accelerate discovery processes, and provide deeper insights into the structure-property relationships of carbon nitride. The synergistic effect of combining ML with traditional experimental approaches is highlighted, showcasing studies where ML driven models have successfully predicted novel carbon nitride compositions with enhanced functional properties. Future directions in this field are also proposed, emphasizing the need for high-quality datasets, advanced ML models, and interdisciplinary collaborations to fully realize the potential of carbon nitride materials in next-generation technologies.
Materials Science (cond-mat.mtrl-sci), Disordered Systems and Neural Networks (cond-mat.dis-nn), Data Analysis, Statistics and Probability (physics.data-an)
Phys. Chem. Chem. Phys., 2025,27, 4531-4566
Bulk Ferroelectric Heterostructures for High Temperature Lead-Free Piezoelectrics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-15 20:00 EDT
Yizhe Li, Ziqi Yang, Ying Chen, Zhenbo Zhang, YunLong Tang, Matthew Smith, Matthew Lindley, Xuezhen Cao, David G. Hopkinson, Andrew J. Bell, Steven J. Milne, Antonio Feteira, Sarah J. Haigh, Alexander S. Eggeman, Juncheng Pan, Jiajun Shi, David A. Hall
Remarkable exploitation of valence and lattice mismatch in epitaxial ferroelectric heterostructures generates physical effects not classically expected for perovskite oxides, such as 2D electron gas and polar skyrmions. However the widespread application of these interfacial properties and functionalities is impeded by the ultrathin layered structure and essential presence of underlying lattice-matched substrates for the deposition of epitaxial thin films. Here, we report a bottom-up pathway to synthesize bulk ferroelectric heterostructures (BFH) with periodic composition fluctuation (8 nm in wavelength) using elemental partitioning by cation diffusion, providing opportunities to exploit novel characteristics of hetero-epitaxial oxide thin films in bulk materials. Exemplar monolithic BiFeO3-BaTiO3 BFH ceramics described herein share common features with their thin film heterostructure counterparts, which facilitates control and stabilisation of ferroelectric polarisation along with a significant enhancement in Curie temperature, Tc, and functionality. BFH ceramics exhibit a record Tc (up to 824 °C) and a piezoelectric coefficient (d33 = 115 pC N-1 ), in comparison with other perovskite or non-perovskite solid solutions, providing sustainable solutions for emergent high temperature piezoelectric sensing, actuation and energy conversion applications. By creating BFH ceramics using different electromechanical boundary conditions, distinct morphologies of aliovalent A-site cation segregated regions along with different types of ferroelectric order are achieved. This formation mechanism provides unprecedented control over local ferroelectric ordering and domain stabilisation in BFH ceramics; it also paves the way to explore new types of functionality, beyond those achievable in both bulk ferroelectrics and thin film heterostructures.
Materials Science (cond-mat.mtrl-sci)
Emergent Distance from Mutual Information in the Critical 1D XXZ Spin Chain
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-15 20:00 EDT
The possibility that spatial geometry may emerge from the entanglement structure of a quantum many-body system is a subject of fundamental interest. Here, we propose and numerically test a candidate distance metric in 1D, d_E, defined purely from quantum mutual information (I) via the relation d_E = K_0 / sqrt(I). Using large-scale density-matrix renormalization group (DMRG) simulations, we compute this emergent distance for the ground state of the 1D spin-1/2 XXZ chain, a canonical model system. Our simulations show that in the quantum critical phase at anisotropy $ \Delta = 1.0$ , the mutual information exhibits a power-law decay consistent with the emergence of a valid metric space. In stark contrast, within the gapped, antiferromagnetic phase ($ \Delta = 2.0$ ), where mutual information decays exponentially, the emergent distance grows exponentially, a behavior inconsistent with the triangle inequality. These results provide numerical evidence that this information-theoretic definition can yield a well-behaved geometry in critical systems, offering a quantitative tool for probing quantum phases and motivating further analytical investigation into the foundations of emergent space.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
6 pages + 1 figure. v1 presents a numerical proof-of-concept. Source code and raw data available at this https URL (DOI: https://doi.org/10.5281/zenodo.15874267)
Distinct Uniaxial Stress and Pressure Fingerprint of Superconductivity in the 3D Kagome Lattice Compound CeRu2
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-15 20:00 EDT
O. Gerguri, D. Das, V. Sazgari, H.X. Liu, C. Mielke III, P. Kràl, S.S. Islam, J.N. Graham, V. Grinenko, R. Sarkar, T. Shiroka, J.-X. Yin, J. Chang, R. Thomale, H.H. Klauss, R. Khasanov, Y. Shi, H. Luetkens, Z. Guguchia
The exploration of tunable superconductivity in strongly correlated electron systems is a central pursuit in condensed matter physics, with implications for both fundamental understanding and potential applications. The Laves phase CeRu$ {2}$ , a pyrochlore compound, exhibits a three-dimensional (3D) Kagome lattice type geometry giving rise to flat bands and degenerate Dirac points, where band structure features intertwine with strong multi-orbital interaction effects deriving from its correlated electronic structure. Here, we combine muon spin rotation ($ \mu$ SR), uniaxial in-plane stress, and hydrostatic pressure to probe the superconducting state of CeRu$ {2}$ . Uniaxial stress up to 0.22 GPa induces a dome-shaped evolution of the critical temperature $ T{\rm c}$ , with an initial plateau, successively followed by enhancement and suppression without any structural phase transition. Stress is further found to drive a crossover from anisotropic to isotropic $ s$ -wave pairing. In contrast, hydrostatic pressure up to 2.2 GPa leaves $ T{\rm c}$ largely unchanged but alters the superfluid density from exponential to linear behavior at low temperatures, indicative of nodal superconductivity under hydrostatic pressure. Taken together, these results indicate that CeRu$ _{2}$ occupies an ideal position in parameter space, enabling highly responsive and multifold tunability of superconductivity in this three-dimensional correlated electronic system. This warrants further quantitative analysis of the interplay between lattice geometry, electronic correlations, and pairing symmetry.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci)
9 pages, 4 Figures
Observation of Quantum Coulomb Blockade Facilitated by P-Donor Molecules in Silicon Nano-Transistor
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-15 20:00 EDT
Soumya Chakraborty, Pooja Sudha, Hemant Arora, Daniel Moraru, Arup Samanta
Multi-donor architecture developed on the base of silicon technology holds significant potential towards room-temperature qubit and other single-electron tunneling (SET) functionalities. However, within such architecture, the overlap of multiple donor wave-functions results in a complex internal electronic configuration with discrete energy levels. Probing these discrete states, observed as multiple conductance peaks, is essential for understanding inter-donor coupling and exchange interactions towards coherent electron transfer. In this direction, we have experimentally demonstrated one-by-one electron filling within multiple-donor molecules with the fundamental analysis of clear and sustained quantum Coulomb blockade (QCB) effect. Moreover, the underlying physics of molecular orbitals, where the increasing energy leads to a larger spatial extent of the corresponding orbital, has been reflected by the systematic decrement of the respective charging-energies. The molecular energy levels, resulting from the orbital hybridization of individual donors, are also confirmed through first-principles simulations using density functional theory (DFT). Furthermore, Monte Carlo simulations based on the orthodox theory of Coulomb blockade support the observed QCB characteristics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph), Quantum Physics (quant-ph)
Learning a potential formulation for rate-and-state friction
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-15 20:00 EDT
Shengduo Liu, Kaushik Bhattacharya, Nadia Lapusta
Empirical rate-and-state friction laws are widely used in geophysics and engineering to simulate interface slip. They postulate that the friction coefficient depends on the local slip rate and a state variable that reflects the history of slip. Depending on the parameters, rate-and-state friction can be either rate-strengthening, leading to steady slip, or rate-weakening, leading to unsteady stick-slip behavior modeling earthquakes. Rate-and-state friction does not have a potential or variational formulation, making implicit solution approaches difficult and implementation numerically expensive. In this work, we propose a potential formulation for the rate-and-state friction. We formulate the potentials as neural networks and train them so that the resulting behavior emulates the empirical rate-and-state friction. We show that this potential formulation enables implicit time discretization leading to efficient numerical implementation.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
From Spheres to Cones: Structural Instabilities and Acidity at Conical Regions in Trivalent Metal Ion Nano-clusters
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-15 20:00 EDT
Jihong Shi, Han Nguyen, Mateo Pescador Arboleda, Styliani Consta
Sub-nanometer aqueous clusters containing a single trivalent metal cation can exhibit charge-induced structural instabilities. Here, we present computational evidence that clusters containing a single \ce{Fe^{3+}}, \ce{Lu^{3+}}, or \ce{La^{3+}} ion undergo continuous geometric transformations as a consequence of this instability. These clusters dynamically evolve across their potential energy landscape, adopting triangular, elongated two-point, single-point, and more spherical configurations often with distinct conical surface protrusions. The manifestation of this instability differs from that observed in mesoscopic and microscopic droplets containing macroions, where stable ``star-like’’ structures form, characterized by a specific number of conical protrusions that varies with the droplet size. In the present study, we find that the orientation of the \ce{H2O} molecules surrounding the metal ion is influenced not only by the electric field of the trivalent ion but also by the local conical protrusions. To further investigate the local acidity in the conical protrusions, we employ a proxy model system consisting of an aqueous nano-cluster containing three \ce{H3O+} ions, simulated using ab initio molecular dynamics. Within the conical regions of the cluster, protons exhibit diffusion across several water molecules, in contrast to the more localized proton delocalization observed in the compact body of the cluster. These findings suggest that local geometry can significantly modulate acidity in highly charged nano-clusters, with potential implications for understanding charge-transfer and ionization mechanisms in techniques such as electrospray ionization mass spectrometry and complement interpretations from infrared spectroscopic data.
Soft Condensed Matter (cond-mat.soft)
Field-effect transistors based on charged domain walls in van der Waals ferroelectric α-In$_2$Se$_3$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-15 20:00 EDT
Shahriar Muhammad Nahid, Haiyue Dong, Gillian Nolan, Andre Schleife, SungWoo Nam, Pinshane Y. Huang, Nadya Mason, Arend M. van der Zande
Charged domain walls (CDW) in ferroelectrics are emerging as functional interfaces with potential applications in nonvolatile memory, logic, and neuromorphic computing. However, CDWs in conventional ferroelectrics are vertical, buried, or electrically inaccessible interfaces that prevent their use in functional devices. Here, we overcome these challenges by stacking two opposite polar domains of van der Waals ferroelectric $ \alpha$ -In$ _2$ Se$ _3$ to generate artificial head-head (H-H) CDWs and use edge contact to fabricate charged domain wall-based field-effect transistors (CDW-FET). We relate the atomic structure to the temperature-dependent electrical and magneto-transport of the CDW-FET. CDW-FETs exhibit a metal-to-insulator transition with decreasing temperature and enhanced conductance and field-effect mobility compared to single domain $ \alpha$ -In$ _2$ Se$ _3$ . We identify two regimes of transport: variable range hopping due to disorder in the band edge below 70 K and thermally activated interfacial trap-assisted transport above 70 K. The CDW-FETs show room-temperature resistance down to 3.1 k$ \Omega$ which is 2-9 orders of magnitude smaller than the single CDW in thin-film ferroelectrics. These results resolve longstanding challenges with high CDW resistance and their device integration, opening opportunities for gigahertz memory and neuromorphic computing.
Materials Science (cond-mat.mtrl-sci)
Enhancement of superconductivity outside Abrikosov vortex core in a tightly bound Cooper pair superconductor
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-15 20:00 EDT
Eugene B. Kolomeisky, Mia Kyler, Ishaan U. Patel
Abrikosov vortices play a central role in the disruption of superconductivity in type-II superconductors. It is commonly accepted that as one moves away from the vortex’s axis, the density of superconductive electrons gradually increases from zero to its bulk value. However, we demonstrate that this behavior is qualitatively altered in the zero-temperature limit provided that the Cooper pairs comprising the superconductive liquid are sufficiently tightly bound. Specifically, outside the vortex core, the density of superconductive electrons reaches a maximum surpassing its bulk value. This phenomenon has electrostatic origins: since normal electrons are absent and there exists a charged ionic background, the spatial variation of the charge density of superconductive electrons violates local neutrality, leading to the generation of an electric field. This electric field shrinks the vortex core and turns the density profile into that with a maximum, ensuring global neutrality. The effect is most pronounced in the limit of strong electrostatic screening, where the field configurations describing the vortex attain a universal form, with the electric field screened over a length scale determined by the London penetration depth.
Superconductivity (cond-mat.supr-con), Pattern Formation and Solitons (nlin.PS)
10 pages, 2 figures
Thermodynamic adsorption potential of superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-15 20:00 EDT
Jiu Hui Wu, Jiamin Niu, Kejiang Zhou
Based on the general thermodynamic analysis of Polanyi adsorption potential, the adsorption potential condition for superconductors is obtained exactly by using the quantum state equation we presented. Because this adsorption potential results in changes of electron concentration, temperature and pressure in a certain volume (adsorption space) adjacent to the surface of the lattice, the composition and structure of superconductors are of course decisive for the adsorption potential. Then we calculate the molar adsorption potentials for those typical superconductors, and find that it is positively correlated to the superconductivity temperature , which reveals that those high-superconductors are mainly determined by the higher molar adsorption potentials. In addition, the adsorption potential at still works despite the disappearance of the energy gap of the BCS theory. This shows that beyond the electron-phonon interaction mechanism, the Cooper-paired electrons are mainly formed by this physical adsorption potential for high-superconductors. This adsorption potential theory could explain almost all common facts about high-temperature superconductors, including many anomalies of the normal and superconducting states.
Superconductivity (cond-mat.supr-con), Quantum Physics (quant-ph)
Intertwined charge, spin, and orbital degrees of freedom under electronic correlations in the one-dimensional Fe$^{3+}$ chalcogenide chain
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-15 20:00 EDT
Yang Zhang, Pontus Laurell, Gonzalo Alvarez, Adriana Moreo, Thomas A. Maier, Ling-Fang Lin, Elbio Dagotto
Motivated by recent developments in the study of quasi-one-dimensional iron systems with Fe$ ^{2+}$ , we comprehensively study the Fe$ ^{3+}$ chalcogenide chain system. Based on first-principles calculations, the Fe$ ^{3+}$ chain has a similar electronic structure as discussed before in the iron 2+ chain, due to similar Fe$ X_4$ ($ X$ = S or Se) tetrahedron chain geometry. Furthermore, a three-orbital electronic Hubbard model for this chain was constructed by using the density matrix renormalization group method. A robust antiferromagnetic coupling was unveiled in the chain direction. In addition, in the intermediate electronic correlation $ U/W$ region, we found an interesting orbital-selective Mott phase with the coexistence of localized and itinerant electrons ($ U$ is the on-site Hubbard repulsion, while $ W$ is the electronic bandwidth). Furthermore, we do not observe any obvious pairing tendency in the Fe$ ^{3+}$ chain in the electronic correlation $ U/W$ region, where superconducting pairing tendencies were reported before in iron ladders. This suggests that superconductivity is unlikely to emerge in the Fe$ ^{3+}$ systems. Our results establish with clarity the similarities and differences between Fe$ ^{2+}$ and Fe$ ^{3+}$ iron chains, as well as iron ladders.
Strongly Correlated Electrons (cond-mat.str-el)
Emerging kinetic-exchange for the enhanced metallic ferromagnetism in CrGeTe$_3$ under pressure
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-15 20:00 EDT
Jiaming Liu, Xuefeng Zhang, Hongbin Qu, Xiaoqun Wang, Hai-Qing Lin, Gang Li
The microscopic origin of ferromagnetism in correlated materials remains heavily debated, particularly for the competing mechanisms governing insulating versus metallic phases. In this work, we theoretically study the electronic structure evolution of CrGeTe$ _{3}$ under pressure and provide a consistent explanation to three unique features of this system, i.e. the semiconducting ferromagnetism at low pressure, the metallic ferromagnetism at high pressure, and the enhanced Curie temperature in the metallic phase. We propose that it is the reduced electronic correlation and enhanced $ d$ -$ p$ hybridization that universally drive the continuous evolution of CrGeTe$ _{3}$ under pressure and glue the three distinct experimental observations. Central to our discovery is the dual role of metallicity – it simultaneously establishes kinetically driven exchange via $ d$ -$ p$ hybridization and enables Stoner-type magnetic instability, with the contribution also from the residual super-exchange. Our analyses reveal that {\it intraband} excitations dominate the pressure-enhanced $ \omega_p^2$ and $ T_c$ correlation. These findings establish $ d$ -$ p$ hybridization and electronic correlation as the bridge between localized and itinerant magnetism, at least, in CrGeTe$ _{3}$ .
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
main text with 6 pages and 4 figures. Supplementary Information is included with 9 pages and 6 figures
The electronic and transport properties in the Haldane-Hubbard with odd-parity altermagnetism
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-15 20:00 EDT
Minghuan Zeng, Zheng Qin, Ling Qin, Shiping Feng, Dong-Hui Xu, Rui Wang
The sublattice current is recently proposed as a feasible scheme to realize the odd-parity altermagnetism(ALM) by breaking the nonmagnetic time reversal symmetry. We first adopt the spin group method to analyze why the broken nonmagnetic time reversal symmetry(TRS) is the sufficient condition for the odd-parity ALM, and find that it is the symmetry $ [\bar{C}2||\bar{E}]$ that allows the appearance of the odd-parity ALM where $ \bar{C}2$ represents a $ 180^\circ$ rotation around an axis perpendicular to the spins combined with the spin-space inversion, and $ \bar{E}$ is the inversion in real space. As a representative example with the presence of sublattice currents, the optical conductivity of Haldane-Hubbard model is further studied using the Kubo formula. It is shown that there is no spin-polarized electrical current in both the longitudinal and traverse directions because of TRS in the odd-parity ALM, and they display a significant peak in the vicinity of the single-particle direct energy gap which reflects that both the longitudinal and traverse optical conductivities are dominated by the quasiparticle excitations around the Dirac points. We also study the hole doping dependence of the anomalous Hall conductivity $ \sigma{\rm Hall}$ as well as the staggered magnetization $ M$ , and find that they display opposite behaviors, i.e., $ \sigma{\rm Hall}$ in the ALM CI state is diminished monotonically from its initial value $ C=2$ at half-filling as the hole doping is increased, while in the ALMI state exhibits a non-monotonous behavior.
Strongly Correlated Electrons (cond-mat.str-el)
7 pages, 2 figures
Observation of Integer and Fractional Chern insulators in high Chern number flatbands
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-15 20:00 EDT
Jingwei Dong, Le Liu, Jundong Zhu, Zitian Pan, Yu Hong, Zhengnan Jia, Kenji Watanabe, Takashi Taniguchi, Luojun Du, Dongxia Shi, Wei Yang, Guangyu Zhang
The intertwined electron correlation and topology give birth to emergent quantum phenomena with fractionalized phases in condensed matter physics. Recently, Chern insulators and fractional ones with C smaller than one have been observed in twisted MoTe2 and rhombohedral pentalayer graphene-hBN moire systems at zero magnetic fields, resembling the fractional quantum Hall phases at high magnetic fields. Here, we target topological phases with high Chern number C > 1 by designing a new moire system, i.e. twisted rhombohedral trilayer-bilayer graphene. We observe Chern insulators with C = 3 at both v = 1 and v = 3. In particular, quantized anomalous Hall effect with C = -3 is observed at v = 3 for device D2. Most importantly, by fractionally filling the high Chern number flat band, we observe evidence of a fractional Chern insulator with C = -3/2 developing from even-denominator fractional filling v = 5/2 at zero magnetic fields, which reaches a fractionally quantized Hall effect with C = -3/2 (a quantization accuracy of 96%) at B = 4T. We have observed another FCI with C = -6/5 at v = 12/5, supported by the Streda formula and anomalous Hall effects induced time reversal symmetry breakings. In addition, we observe Chern insulators with C = 1 and 2 at even-denominator fractional filling v = 1/2 and 3/2, respectively, and strikingly, the signatures of anomalous Hall crystal phases with high Chern numbers (C > 1) that develops continuously from v = 1 to the even-denominator v = 3/2 at zero magnetic fields in device D1 and D3. Our results demonstrate the tRTBG, which can be naturally extended to other twisted graphene moire superlattices based on rhombohedral graphene multilayers, as a novel platform for hosting unconventional high Chern number correlated topology in the ultra-strong correlated regime that is beyond the paradigm of the fractional phases with C < 1.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
21 pages, 4 Figures, and 8 supporting figures. Comments are welcome!
An analytical model for the remote epitaxial potential
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-15 20:00 EDT
Jason K Kawasaki, Quinn T Campbell
We propose an analytical model for the remote bonding potential of the substrate that permeates through graphene during remote epitaxy. Our model, based on a Morse interatomic potential, includes the attenuation due to (1) the increased separation between film and substrate and (2) free carrier screening from graphene. Compared with previous slab density functional theory calculations, which use the electrostatic potential as a proxy for bonding, our analytical model provides a more direct description of bonding, explicitly includes screening (which is often ignored), and is based on simple, interpretable, and well benchmarked parameters. We show that the magnitude of $ |\phi_{remote}|$ for typical semiconductor and oxide substrates is few meV, similar to the van der Waals potential of graphene. This suggests interference between the graphene and remote substrate potentials, plus interfacial reconstructions, must be considered when interpreting experiments on remote epitaxy. We use our model to interpret previous experiments from the remote epitaxy and related literature, highlighting connections to moire epitaxy and to the ordering of graphite intercalation compounds. Our model also points to tests, based on tunable screening and spatial extent of the substrate potential, that may increase the strength of the remote potential towards the more idealized picture.
Materials Science (cond-mat.mtrl-sci)
First-Principles Theory of Five- and Six-Phonon Scatterings
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-15 20:00 EDT
Higher-order phonon scatterings beyond fourth order remain largely unexplored despite their potential importance in strongly anharmonic materials at elevated temperatures. We develop a theoretical formalism for first-principles calculation of five- and six-phonon scatterings using Green’s function techniques based on a diagrammatic formalism, and systematically investigate multi-phonon interactions in Si, MgO, and BaO from room temperature to near melting points. Our calculation reveals dramatically different material-dependent behaviors: while five- and six-phonon processes remain negligible in Si, they become increasingly important in MgO and dominant in BaO near its melting point, where they surpass three- and four-phonon scattering intensity and significantly reduce lattice thermal conductivity. We demonstrate that the strength of higher-order interactions is primarily governed by interatomic force constants, with BaO exhibiting five- and six-phonon scattering rates over one order of magnitude stronger than MgO despite identical crystal structures, due to large scattering phase space arising from softened harmonic interactions. Our work establishes the theoretical foundation for understanding lattice dynamics and thermal transport in strongly anharmonic materials and at elevated temperatures.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
Hypergraph-Based Models of Random Chemical Reaction Networks: Conservation Laws, Connectivity, and Percolation
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-15 20:00 EDT
Shesha Gopal Marehalli Srinivas, Massimiliano Esposito, Nahuel Freitas
Random graph models have been instrumental in characterizing complex networks, but chemical reaction networks (CRNs) are better represented as hypergraphs. Traditional models of random CRNs often reduce CRNs to bipartite graphs, representing species and reactions as distinct nodes, or simpler derived graphs, which can obscure the relationship between the statistical properties of these representations and the physical characteristics of the CRN. We introduce a straightforward model for generating random CRNs that preserves their hypergraph structure as well as atomic composition, enabling the direct study of chemically relevant features. Notably, our approach distinguishes two notions of connectivity that are equivalent in graphs but differ fundamentally in hypergraphs. These notions exhibit percolation-like phase transitions, which we analyze in detail. The first type of connectivity has relevance to steady-state synthesis and transduction, determining the effective reactions an open CRN can perform at steady state. The second type is suitable to identify which species can be produced from a given initial set of species in a closed CRN. Our findings highlight the importance of hypergraph-based modeling for uncovering the complex behaviors of CRNs.
Statistical Mechanics (cond-mat.stat-mech), Molecular Networks (q-bio.MN)
30 pages, 30 figures
Crossover in the Ordered Phase in the Non-Mermin-Wagner-Hohenberg Regime of Spin Models with Long-Range Coupling
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-15 20:00 EDT
Jiewei Ding, Jiahao Su, Ho-Kin Tang, Wing Chi Yu
Continuous spin models with long-range interactions of the form $ r^{-\sigma}$ , where $ r$ is the distance between two spins and $ \sigma$ controls the decay of the interaction, exhibit enhanced order that competes with thermal disturbances, leading to a richer variety of phases and types of phase transitions. In-depth research in this area not only aids in comprehending the complex behaviors in theoretical models but also provides valuable insights into the diverse phase transitions observed in real materials. Here, we identify that the true long-range ordered phase encompasses distinct scaling regimes, which we term Enhance Long-Range Ordered (EnLRO) and Reduce Long-Range Ordered (ReLRO) regimes. In the one-dimensional XY model, the crossover from EnLRO to ReLRO regimes occurs around $ \sigma \approx 1.575$ , while in two dimensions, the crossover happens near $ \sigma \approx 3.2$ . Applying finite-size scaling analysis, we extract the critical exponents that characterize the order-to-disorder phase transitions in the EnLRO and ReLRO regimes, constructing comprehensive phase diagrams. The analysis is further extended to the 1D and 2D long-range Heisenberg models, where we find the EnLRO-ReLRO crossover at $ \sigma \approx 1.575$ and $ \sigma \approx 3.22$ , respectively. The similar crossover points suggest that the distinction between EnLRO and ReLRO regimes is a generic feature in continuous spin models with long-range interactions.
Statistical Mechanics (cond-mat.stat-mech)
16 pages, 14 figures
Observation of Chiral Phonons in Methylbenzylammonium Lead Iodide
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-15 20:00 EDT
Sankaran Ramesh, Prasenjit Mandal, Pratik Bhagwat, Yong Li, Tönu Pullerits, Dmitry Baranov
An optical phonon at 2.5 meV is observed in a thin film of the chiral metal halide (R-MBA)$ _2$ PbI$ _4$ , but is absent in the racemic counterpart, as revealed by femtosecond transient absorption spectroscopy. This experimental result indicates the chiral origin of the 2.5 meV mode and supports recent theoretical predictions of chirality transfer from the organic to the inorganic layers, with implications for the spin polarization properties of hybrid metal halides and perovskites.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Chemical Physics (physics.chem-ph)
4 pages, 1 Figure, Supporting Information
Eight-fold classification of superconducting orders
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-15 20:00 EDT
Alexander V. Balatsky, Saikat Banerjee
We present a thorough symmetry-based classification of superconducting order parameters that is independent of their microscopic origins. Our approach involves classifying pairing states through the pairwise permutation of spatial, temporal, spin, and orbital indices, focusing on the parities of the relative coordinates and times of the paired fields. This framework leads to the emergence of new classes of superconducting states, which we visualize as a multidimensional cube representing the relative parities in space and time, referred to as the Berezinskii-Abrahams hypercube. While some predicted states, such as odd-frequency superconductors, have been previously discussed, our symmetry analysis also reveals states that have yet to be explored, including odd-frequency Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) states. Furthermore, we draw parallels to the classification of particle-hole states, and reiterate the possibility of new states, such as odd-frequency density waves.
Superconductivity (cond-mat.supr-con)
8 pages, 5 figues, and 1 table. Comments are welcome
Evidence of rotational and tilting disorder of ReO6 octahedra in single crystals of a 5d1 double perovskite Ba2CaReO6
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-15 20:00 EDT
Alasdair Nicholls, Jian-Rui Soh, Yikai Yang, Alessandro Bombardi, Daigorou Hirai, Henrik M. Ronnow, Ivica Zivkovic
We present results of an experimental study on single crystals of a 5d1 double perovskite Ba2CaReO6. Magnetization measurements reveal a weak splitting between zero-field-cooled and field-cooled protocols below 12 K. At magnetic fields above 1 T the splitting is absent and the magnetic susceptibility is featureless. A detailed specific heat study in a wide temperature range and comprising different heat pulses did not reveal any indication of a thermodynamic phase transition. At low temperatures we do observe specific heat deviating from a phonon background, leading to a total electronic entropy release of ~Rln2. Resonant and non-resonant x-ray diffraction of characteristic Bragg peaks indicates a significant presence of disorder, potentially related to random tilts and rotations of rigid ReO6 octahedra.
Strongly Correlated Electrons (cond-mat.str-el)
Active anisotropic diffusion of microparticles in nematic lyotropic chromonic liquid crystal powered by light
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-15 20:00 EDT
Patrycja Kadzialka, Lech Sznitko, Pawel Karpinski
We explore the diffusion dynamics of a Brownian microparticle in a lyotropic chromonic liquid crystal (LCLC). In the planarly oriented nematic phase, the microparticle exhibits levitation and anisotropic two-dimensional diffusion. Upon illumination with light resonant with the absorption spectrum of the solution, we observe a transition to active anisotropic diffusion, driven by the disruption of the molecular stacking in the liquid crystal. Notably, while light absorption increases both the molecular kinetic energy and the overall temperature of the solution, it manifests at the microscopic level as anisotropic active diffusion of the microparticles, revealing a novel light-driven non-equilibrium transport mechanism.
Soft Condensed Matter (cond-mat.soft)
Temperature dependence of surface superconductivity in t-PtBi$_2$
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-15 20:00 EDT
Julia Besproswanny, Sebastian Schimmel, Yanina Fasano, Grigory Shipunov, Saicharan Aswartham, Danny Baumann, Bernd Büchner, Christian Hess
The Weyl semimetal trigonal PtBi$ _2$ has recently been identified as a promising candidate material for intrinsic topological surface superconductivity emerging from the Fermi arc states of the material with a sizeable superconducting gap. We report the temperature evolution of the superconducting excitation spectrum using scanning tunneling spectroscopy in the range of $ 8-45,$ K. A large low-temperature gap in the order of $ \Delta \approx 9,$ meV and a closing of the gap around $ T_c \approx 45,$ K is observed. Thus, our results confirm the previously indicated high $ T_c$ -like superconductivity in t-PtBi$ _2$ .
Superconductivity (cond-mat.supr-con)
The Effect of Pearl Vortices on the Shape and Position of Néel-Type Skyrmions in Superconductor–Chiral Ferromagnet Heterostructures
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-15 20:00 EDT
S. S. Apostoloff, E. S. Andriyakhina, I. S. Burmistrov
This review presents recent work carried out at the Landau Institute for Theoretical Physics of the Russian Academy of Sciences on the study of the effect of superconducting vortices on the shape and position of Néel-type skyrmions in superconductor–chiral ferromagnet heterostructures. Based on analytical and numerical approaches, a number of effects caused by the inhomogeneous magnetic field of the vortex have been predicted: a significant increase in the skyrmion radius, a change in its chirality in the case of a coaxial configuration of the vortex and skyrmion, and modification of the skyrmion shape in the case of an eccentric configuration. Recent experiments studying these effects are discussed.
Superconductivity (cond-mat.supr-con)
Accepted for publication; to appear in Physics Uspekhi
Bulk spin-orbit torque-driven spin Hall nano-oscillators using PtBi alloys
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-15 20:00 EDT
Utkarsh Shashank, Akash Kumar, Tahereh Sadat Parvini, Hauke Heyen, Lunjie Zeng, Andrew B. Yankovich, Mona Rajabali, Eva Olsson, Markus Münzenberg, Johan Åkerman
Spin-orbit-torque-driven auto-oscillations in spin Hall nano-oscillators (SHNOs) offer a transformative pathway toward energy-efficient, nanoscale microwave devices for next-generation neuromorphic computing and high-frequency technologies. A key requirement for achieving robust, sustained oscillations is reducing the threshold current ($ I_{\text{th}}$ ), strongly governed by spin Hall efficiency ($ \theta_{\text{SH}}$ ). However, conventional strategies to enhance $ \theta_{\text{SH}}$ face trade-offs, including high longitudinal resistivity, interfacial effects, and symmetry-breaking torques that limit performance. Here, we demonstrate a substantial enhancement of the bulk spin Hall effect in PtBi alloys, achieving over a threefold increase in $ \theta_{\text{SH}}$ , from 0.07 in pure Pt to 0.24 in Pt$ _{94.0}$ Bi$ _{6.0}$ and 0.19 in Pt$ {91.3}$ Bi$ {8.7}$ , as extracted from DC-bias spin-torque ferromagnetic resonance. The enhanced $ \theta{\text{SH}}$ originates from bulk-dominated, extrinsic side-jump scattering across all PtBi compositions. Correspondingly, we observe a 42% and 32% reduction in $ I{\text{th}}$ in 100 nm SHNOs based on Co$ _{40}$ Fe$ _{40}$ B$ _{20}$ (3 nm)/Pt$ _{94.0}$ Bi$ _{6.0}$ (4 nm) and Co$ _{40}$ Fe$ _{40}$ B$ _{20}$ (3 nm)/Pt$ {91.3}$ Bi$ {8.7}$ (4 nm), respectively. Structural characterization reveals reduced Pt crystallinity, along with emergence of preferred crystallographic orientations upon introducing higher Bi concentrations. Together, these results position PtBi alloys as a compelling alternative to conventional 5$ d$ transition metals, enabling enhanced $ \theta{\text{SH}}$ and significantly lower $ I{\text{th}}$ , thus opening new avenues for energy-efficient neuromorphic computing and magnetic random access memory.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph)
19 pages, 5 figures
Unveiling the Self-Orthogonality at Exceptional Points in Driven $\mathcal{PT}$-Symmetric Systems
New Submission | Other Condensed Matter (cond-mat.other) | 2025-07-15 20:00 EDT
Alexander Fritzsche, Riccardo Sorbello, Ronny Thomale, Alexander Szameit
We explore the effect of self-orthogonality at exceptional points (EPs) in non-Hermitian Parity-Time-symmetric systems. Using a driven three-band lattice model, we show that the Rabi frequency diverges as the system approaches an EP due to the coalescence of eigenstates. We demonstrate that this divergence manifests in experimentally accessible power oscillations, establishing a direct observable for self-orthogonality. Our results provide a pathway for probing EP physics in various metamaterial platforms.
Other Condensed Matter (cond-mat.other), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
15 pages, 8 figures
Quantum-Annealing Enhanced Machine Learning for Interpretable Phase Classification of High-Entropy Alloys
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-15 20:00 EDT
Diego Ibarra Hoyos, Gia-Wei Chern, Israel Klich, Joseph Poon
High entropy alloys (HEAs) offer unprecedented compositional flexibility for designing advanced materials, yet predicting their crystallographic phases remains a key bottleneck due to limited data and complex phase formation behavior. Here, we present a quantum-enhanced machine learning framework that leverages quantum annealing to enhance phase classification in HEAs. Our pipeline integrates Quantum Boosting (QBoost) for interpretable feature selection and classification, with Quantum Support Vector Machines (QSVM) that use quantum-enhanced kernels to capture nonlinear relationships between physical descriptors. By reformulating both models as Quadratic Unconstrained Binary Optimization (QUBO) problems, we exploit the efficient sampling capabilities of quantum annealers to achieve rapid training and robust generalization, demonstrating notable runtime reductions relative to classical baselines in our setup. We target six key phases: FCC, BCC, Sigma, Laves, Heusler, and AlXY B2, and benchmark model performance using both cross-validation and a rigorously curated test set of prior experimentally synthesized HEAs. The results confirm strong alignment between predicted and measured phases. Our findings demonstrate that quantum-enhanced classifiers match or exceed classical models in accuracy and offer insights grounded in interpretable physical descriptors. This work constitutes an important step toward practical quantum acceleration in materials discovery pipelines.
Materials Science (cond-mat.mtrl-sci)
Rigid-Body Anisotropy in Noncollinear Antiferromagnets
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-15 20:00 EDT
Characterizing the anisotropic structure in noncollinear antiferromagnets is essential for antiferromagnetic spintronics. In this work, we provide a microscopic theory linking the anisotropy effects induced by the rigid-body rotation of spin order to spin-orbit coupling. Our method goes beyond the conventional magnetic group theory, offering a concise yet powerful tool to characterize diverse anisotropy effects in complex magnetic systems. Using the group representation theory of the spin group, we obtain a set of basis functions formed from tensor elements of spin-orbit vector–which originates from spin-orbit coupling and is tied to the rigid-body rotation of the spin order–to systematically describe the structure of anisotropy effects. As a concrete example, we apply our framework to coplanar antiferromagnets Mn$ _3$ Sn and Mn$ _3$ Ir, demonstrating that the corresponding basis functions can well capture both the geometric and magnitude dependencies of the magnetic anisotropy energy and anomalous Hall conductivity. Finally, we discuss the generalization of our framework to broader classes of anisotropy phenomena in magnetic systems.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
7 pages, 2 figures
Electric-Field Induced Spin Wave Nonreciprocity in Noncoplanar Magnets
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-15 20:00 EDT
Xiao-Hui Li, Yuan-Ming Lu, Yuan Wan
We show that an electric field can induce nonreciprocal spin wave dispersion in magnetic insulators with negligible spin-orbit coupling. The electric field controls the direction and magnitude of nonreciprocity through a nonlinear magnetoelectric effect without switching the magnetic ground state. By deriving spin space group symmetry constraints, we find only a subset of noncoplanar magnets exhibits this property, and identify a few candidates. For the example of hexagonal lattice tetrahedral antiferromagnet, our effective field theory analysis and microscopic model calculation yield results that are fully consistent with the symmetry analysis.
Strongly Correlated Electrons (cond-mat.str-el)
24 pages, 8 figures
Practical Crystallography with a Transmission Electron Microscope
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-15 20:00 EDT
Benjamin L. Weare (1 and 2), Kayleigh L. Y. Fung (3), Ian Cardillo-Zallo (1 and 4), William J. Cull (2), Michael W. Fay (1 and 5), Stephen P. Argent (2), Paul D. Brown (5) ((1) Nanoscale and Microscale Research Centre, University of Nottingham (2) School of Chemistry, University of Nottingham, (3) Department of Computer Science, Nottingham Trent University (4) School of Pharmacy, University of Nottingham (5) Department of Mechanical, Materials, and Manufacturing, Faculty of Engineering, University of Nottingham)
Three-dimensional electron diffraction (3DED) is a powerful technique providing for crystal structure solutions of sub-micron sized crystals too small for structure determination via X-ray techniques. The entry requirement, however, of a transmission electron microscope (TEM) adapted with bespoke software for coordinated sample stage rotation and continuous electron diffraction data acquisition has generally inhibited the wider uptake of 3DED. To address this limitation, we present novel software GiveMeED appropriate for controlled 3DED data acquisition. The collection of useable reflections beyond 0.8 Å makes 3DED crystallographic processing effectively routine, using standard software and workflows derived from single-crystal X-ray diffraction (SCXRD) techniques. A full experimental workflow for 3DED on a conventional TEM is described in practical terms, in combination with direct imaging, and energy dispersive X-ray spectroscopy (EDS) and electron energy loss spectroscopy (EELS), for the return of comprehensive correlative descriptions of crystal morphologies and sample compositions, with due regard for the quantification of electron flux at each stage of the characterisation process. The accuracy and effectiveness of GiveMeED is demonstrated through structure solutions for case study paracetamol, copper(II) phthalocyanine, and percholorocoronene samples, characterised in their near-native states under controlled low dose conditions at either room or cryogenic temperatures, with determined unit cell parameters and atomic connectivity matching accepted literature X-ray structures for these compounds. To promote the wider adoption of 3DED, we make GiveMeED freely available for use and modification, in support of greater uptake and utilisation of structure solution procedures via electron diffraction.
Materials Science (cond-mat.mtrl-sci), Instrumentation and Detectors (physics.ins-det)
Preprint, submitted to Ultramicroscopy 17-Jun-2025. Associated raw data, see this http URL
Dissipation induced Majarona $0$- and $π$-modes in a driven Rashba nanowire
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-15 20:00 EDT
Koustabh Gogoi, Tanay Nag, Arnob Kumar Ghosh
Periodic drive is an intriguing way of creating topological phases in a non-topological setup. However, most systems are often studied as a closed system, despite being always in contact with the environment, which induces dissipation. Here, we investigate a periodically driven Rashba nanowire in proximity to an $ s$ -wave superconductor in a dissipative background. The system’s dynamics is governed by a periodic Liouvillian operator, from which we construct the Liouvillian time-evolution operator and use the third-quantization method to obtain the `Floquet damping matrix’, which captures the spectral and topological properties of the system. We show that the system exhibits edge-localized topological Majorana $ 0$ -modes (MZMs) and $ \pi$ -modes (MPMs). Additionally, the system also supports a trivial $ 0$ -modes (TZMs) and $ \pi$ -modes (TPMs), which are also localized at the edges of the system. The MZMs and the MPMs are connected to the bulk topology and carry a bulk topological invariant, while the emergence of TZMs and TPMs is primarily tied to exceptional points and is topologically trivial. We study the topological phase diagrams in terms of the topological invariants and show that the dissipation can modify the topological phase diagram substantially and even induce topological phases in the system. Our work extends the understanding of a driven-dissipative topological superconductor.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con), Quantum Physics (quant-ph)
11 pages, 3 figures; Comments are welcome
Dislocation-enhanced piezoelectric catalysis of KNbO3 crystal for water splitting
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-15 20:00 EDT
Hanyu Gong, Jiawen Zhang, Yan Zhao, Shan Xiang, Xiang Zhou, Oliver Preuß, Wenjun Lu, Yan Zhang, Xufei Fang
Dislocations in oxides with ionic/covalent bonding hold the potential of harnessing versatile functionalities. Here, high-density dislocations in a large plastic zone in potassium niobate (KNbO3) crystals are mechanically introduced by room-temperature cyclic scratching to enhance piezocatalytic hydrogen production. Unlike conventional energy-intensive, time-consuming deformation at high temperature, this approach merits efficient dislocation engineering. These dislocations induce local strain and modify the electronic environment, thereby improving surface reactivity and charge separation, which are critical for piezocatalysis. This proof-of-concept offers a practical and sustainable alternative for functionalizing piezoelectric ceramics. Our findings demonstrate that surface-engineered dislocations can effectively improve the piezocatalysis, paving the way for efficient and scalable piezocatalytic applications.
Materials Science (cond-mat.mtrl-sci)
High Resolution Temperature-Resolved Spectroscopy of the Nitrogen Vacancy $^{1}E$ Singlet State Ionization Energy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-15 20:00 EDT
Kristine V. Ung, Connor A. Roncaioli, Ronald L. Walsworth, Sean M. Blakley
The negatively charged diamond nitrogen-vacancy ($ \mathrm{ {NV}^-}$ ) center plays a central role in many cutting edge quantum sensing applications; despite this, much is still unknown about the energy levels in this system. The ionization energy of the $ \mathrm{^{1}E}$ singlet state in the $ \mathrm{ {NV}^-}$ has only recently been measured at between 2.25 eV and 2.33 eV. In this work, we further refine this energy by measuring the $ \mathrm{^{1}E}$ energy as a function of laser wavelength and diamond temperature via magnetically mediated spin-selective photoluminescence (PL) quenching; this PL quenching indicating at what wavelength ionization induces population transfer from the $ \mathrm{^{1}E}$ into the neutral $ \mathrm{ {NV}^0}$ charge configuration. Measurements are performed for excitation wavelengths between 450 nm and 470 nm and between 540 nm and 566 nm in increments of 2 nm, and for temperatures ranging from about 50 K to 150 K in 5 K increments. We determine the $ \mathrm{^{1}E}$ ionization energy to be between 2.29 and 2.33 eV, which provides about a two-fold reduction in uncertainty of this quantity. Distribution level: A. Approved for public release; distribution unlimited.
Materials Science (cond-mat.mtrl-sci), Optics (physics.optics), Quantum Physics (quant-ph)
9 pages, 5 figures, invited manuscript for Recent Advances in Diamond Science and Technology - SBDD XXIX special issue of Physica Status Solidi (a)
Electro-optic Kerr Effect Induced by Nonlinear Transport in monolayer WTe2
New Submission | Other Condensed Matter (cond-mat.other) | 2025-07-15 20:00 EDT
He-Lin Li, Zhen-Gang Zhu, Gang Su
The nonlinear Hall effect (NLHE) can induce optical anisotropy by modifying a material’s dielectric tensor, presenting opportunities for novel characterization and device applications. While the magneto-optical Kerr effect (MOKE) probes the linear Hall effect (LHE) in magnetic materials, an analogous optical probe for NLHE in non-magnetic, time-reversal symmetric systems remains highly desirable. Here, we theoretically propose and investigate an NLHE-induced Electro-optic Kerr Effect (EOKE) as such a probe. Focusing on monolayer (ML) WTe$ _2$ , a prototypical NLHE material, our analysis considers contributions from Berry curvature dipole (BCD), Drude, injection, and shift mechanisms. We demonstrate that the EOKE signal in WTe$ _2$ is predominantly governed by the BCD. Furthermore, the Kerr angle exhibits temporal oscillations at different optical frequencies, suggesting EOKE as a promising route for the time-resolved detection of NLHE and the dynamic investigation of material topology.
Other Condensed Matter (cond-mat.other)
8 pages, 5figures
Inertial antiferromagnetic resonance driven by spin-orbit torques
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-15 20:00 EDT
Peng-Bin He, Ri-Xing Wang, Zai-Dong Li, Mikhail Cherkasskii
It is widely accepted that the handedness of a resonant mode is an intrinsic property. We show that, by tailoring the polarization and handedness of alternating spin-orbit torques used as the driving force, the polarization state and handedness of inertial resonant modes in an antiferromagnet can be actively controlled. In contrast to ferromagnets, whose resonant-mode polarization is essentially fixed, antiferromagnetic inertial modes can continuously evolve from elliptic through circular to linear polarization as the driving polarization is varied. We further identify an inertia-dependent critical degree of driving polarization at which the mode becomes linearly polarized while its handedness reverses.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Single-site diagonal quantities capture off-diagonal long-range order
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-15 20:00 EDT
M. Sanino, I. D’Amico, V. V. França, I. M. Carvalho
Quantum phase transitions are typically marked by changes in quantum correlations across various spatial scales within the system. A key challenge lies in the fact that experimental probes are generally restricted to diagonal quantities at the single-site scale, which are widely believed to be insufficient for detecting phases with off-diagonal long-range order, such as superconducting states. In a striking departure from conventional expectations, we show that single-site diagonal descriptors – charge and spin fluctuations, occupation probabilities, and entanglement – can capture the emergence of off-diagonal long-range order in the one-dimensional extended Hubbard model at half-filling. These single-site quantities display clear critical signatures of the superconducting transition, preceded by a continuous breaking of particle-hole symmetry, consistent with a second-order phase transition. While this symmetry breaking has a negligible effect on single-site descriptors, it allows a direct connection between local fluctuations and nonlocal correlations.
Strongly Correlated Electrons (cond-mat.str-el)
Beyond-mean-field fluctuations for the solution of constraint satisfaction problems
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-07-15 20:00 EDT
Niklas Foos, Bastian Epping, Jannik Grundler, Alexandru Ciobanu, Ajainderpal Singh, Tim Bode, Moritz Helias, David Dahmen
Constraint Satisfaction Problems (CSPs) lie at the heart of complexity theory and find application in a plethora of prominent tasks ranging from cryptography to genetics. Classical approaches use Hopfield networks to find approximate solutions while recently, modern machine-learning techniques like graph neural networks have become popular for this task. In this study, we employ the known mapping of MAX-2-SAT, a class of CSPs, to a spin-glass system from statistical physics, and use Glauber dynamics to approximately find its ground state, which corresponds to the optimal solution of the underlying problem. We show that Glauber dynamics outperforms the traditional Hopfield-network approach and can compete with state-of-the-art solvers. A systematic theoretical analysis uncovers the role of stochastic fluctuations in finding CSP solutions: even in the absense of thermal fluctuations at $ T=0$ a significant portion of spins, which correspond to the CSP variables, attains an effective spin-dependent non-zero temperature. These spins form a subspace in which the stochastic Glauber dynamics continuously performs flips to eventually find better solutions. This is possible since the energy is degenerate, such that spin flips in this free-spin space do not require energy. Our theoretical analysis leads to new deterministic solvers that effectively account for such fluctuations, thereby reaching state-of-the-art performance.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
Hole distribution and self-doping enhanced electronic correlation in hole-doped infinite-layer nickelates
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-15 20:00 EDT
Hongbin Qu, Guang-Ming Zhang, Gang Li
The minimal model for infinite-layer nickelates remains under debate, particularly regarding the hybridization between itinerant interstitial-$ s$ and the correlated Ni-3$ d_{x^2-y^2}$ orbitals, as well as the interaction between $ d_{x^2-y^2}$ and other $ 3d$ orbitals. Additionally, how the doped holes in La$ _{1-x}$ Sr$ _x$ NiO$ _2$ are distributed among different orbitals remain unresolved. Motivated by recent angle resolved photoemission spectroscopy (ARPES) experiments, we theoretically study the electronic structure of infinite-layer La$ {1-x}$ Sr$ x$ NiO$ 2$ at various doping levels. We find that, unlike the expectation from a rigid band shift, holes are equally distributed to Ni-3$ d{x^2-y^2}$ and interstitial-$ s$ orbitals. The role of interstitial-$ s$ orbital is further confirmed from the renormalization of Ni-3$ d{x^2-y^2}$ band, for which the coupling between interstitial-$ s$ and Ni-3$ d{x^2-y^2}$ exerts a non-negligible impact on the orbital-selective renormalization observed in ARPES. We also discuss the implication of our results to the single-band model, where the interstitial-$ s$ orbital in the normal state of La$ _{1-x}$ Sr$ _x$ NiO$ 2$ acts as charge donator enhancing the correlation of Ni-3$ d{x^2-y^2}$ by increasing its concentration close to half-filling.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
6 pages, 3 figures
Dynamics of fractional quantum Hall Liquids with a pulse at the edge
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-15 20:00 EDT
Jie Li, Chen-Xin Jiang, Zi-Xiang Hu
Motivated by recent experimental advancements in scanning optical stroboscopic confocal microscopy and spectroscopy measurements, which have facilitated exceptional energy-space-time resolution for investigating edge and bulk dynamics in fractional quantum Hall systems, we formulated a model for the pump-probe process on the edge. Starting with a ground state, we applied a tip potential near the fractional quantum Hall liquid edge, which was subsequently turned off after a defined time duration. By examining how the specific nature of the tip potential influences the evolution of the wave function and its distribution in energy spectrum, we identify that quench dynamics of the edge pulse leads to excitations that spread both along the edge and perpendicularly into the bulk. Moreover, magnetoroton excitations are predominant among the bulk excitations. These results align well with the experimental observations. Furthermore, we analyzed the effects of the tip’s position, intensity, and duration on the dynamics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
9 pages, 8 figures
High-throughput prediction of thermodynamically stable 1D magnetic transition-metal chalcogenides and halides
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-15 20:00 EDT
Canbo Zong, Deping Guo, Renhong Wang, Weihan Zhang, Jiaqi Dai, Zhongqin Zhang, Cong Wang, Xianghua Kong, Wei Ji
The search for novel one-dimensional (1D) materials with exotic physical properties is crucial for advancing nanoelectronics and spintronics. Here, we perform a comprehensive high-throughput, first-principles study to explore the vast landscape of 1D transition-metal chalcogenides and halides. Starting with 6,832 candidate structures derived from 28 metals and 8 non-metals, we systematically evaluated their thermodynamic stability by comparing the formation energies of 1D chains against competing 2D phases, mimicking thermodynamic selectivity during nucleation. This screening identified 210 stable 1D magnetic chains. Furthermore, representation learning models revealed that chemical stoichiometry and the electron affinity of the non-metal element are key factors governing 1D stability. The stable materials exhibit a rich spectrum of properties, including diverse magnetic orders (FM, AFM) and Luttinger compensated antiferromagnetism in MnTe. We discovered 20 ferroelastic chains, with FeTe showing a giant magnetostriction of -5.57%. Other emergent phenomena include Charge Density Wave (CDW) chains in FeTe and NiSe. Finally, our findings propose concrete platforms for quantum applications, such as the predicted realization of Majorana zero modes in a ferromagnetic CrCl2 chain on a superconducting NbSe2 substrate.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
15 pages, 4 figures
Dynamical stability for dense patterns in discrete attractor neural networks
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-07-15 20:00 EDT
Neural networks storing multiple discrete attractors are canonical models of biological memory. Previously, the dynamical stability of such networks could only be guaranteed under highly restrictive conditions. Here, we derive a theory of the local stability of discrete fixed points in a broad class of networks with graded neural activities and in the presence of noise. By directly analyzing the bulk and outliers of the Jacobian spectrum, we show that all fixed points are stable below a critical load that is distinct from the classical \textit{critical capacity} and depends on the statistics of neural activities in the fixed points as well as the single-neuron activation function. Our analysis highlights the computational benefits of threshold-linear activation and sparse-like patterns.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech), Machine Learning (cs.LG), Neural and Evolutionary Computing (cs.NE), Neurons and Cognition (q-bio.NC)
Hollow cylindrical droplets in a very strongly dipolar condensate
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-07-15 20:00 EDT
A harmonically trapped Bose-Einstein condensate (BEC) leads to topologically trivial compact states. Because of the long-range nonlocal dipole-dipole interaction, a strongly dipolar BEC revealed many novel phenomena. Here we show that in a strongly dipolar BEC one can have a hollow cylindrical quasi-one-dimensional metastable droplet with ring topology while the system is trapped only in the $ x$ -$ y$ plane by a harmonic potential and a Gaussian hill potential at the center and untrapped along the polarization $ z$ axis. In this numerical investigation we use the imaginary-time propagation of a mean-field model where we include the Lee-Huang-Yang interaction, suitably modified for dipolar systems. Being metastable, these droplets are weakly stable and we use real-time propagation to investigate its dynamics and establish stability.
Quantum Gases (cond-mat.quant-gas)
Enhanced superconductivity in the compressively strained bilayer nickelate thin films by pressure
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-15 20:00 EDT
Qing Li, Jianping Sun, Steffen Boetzel, Mengjun Ou, Zhe-Ning Xiang, Frank Lechermann, Bosen Wang, Yi Wang, Ying-Jie Zhang, Jinguang Cheng, Ilya M. Eremin, Hai-Hu Wen
The discovery of high temperature superconductivity in the nickelate system has stimulated enormous interest in the community of condensed matter physics. Recently, superconductivity with an onset transition temperature (Tc^onset) over 40 K was achieved in La3Ni2O7 and (La,Pr)3Ni2O7 thin films at ambient pressure due to in-plane compressive strain. This observation has sparked enormous attention because measurements on superconducting properties can be accessible with many commonly used experimental tools. On the other hand, the Tc in these thin films is much lower than that of the bulk bilayer nickelates under pressure. Here we report the enhancement of Tc^onset to over 60 K by applying hydrostatic pressure on the compressively strained superconducting bilayer nickelate thin films. The Tc^onset firstly ramps up with pressure, then it slightly drops down after reaching the maximum Tc^onset at about 61.5 K under a pressure of 9 GPa, showing a dome-like phase diagram. Hall effect measurements reveal that the dominant charge carriers are hole-like with a slight enhancement of charge carrier density with pressure in accompanying with the increase of Tc. Our theoretical results demonstrate that the enhancement of Tc arises from a cooperative amplification of magnetic fluctuations within and between the layers and increased metallicity under pressure. However, this enhancement exhibits saturation at higher pressures. These findings highlight the critical role of the interplay between interlayer and intralayer electronic correlations in bilayer nickelate superconductors and point to the potential of tuning Tc through controlled manipulation of the electronic structure and interactions.
Superconductivity (cond-mat.supr-con)
43 pages, 5 figures in Main Text; 10 figures in Supplementary Information
Relaxation dynamics of a mobile impurity injected in a one-dimensional Bose gas
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-07-15 20:00 EDT
Saptarshi Majumdar, Aleksandra Petković
The nonequilibrium dynamics of a quantum impurity immersed with a finite velocity in a one-dimensional system of weakly interacting bosons is studied. We uncover and characterize different regimes of relaxation dynamics. We find that the final impurity velocity remains constant in a large interval of sufficiently big and realistic initial velocities. The underlying physical mechanism is the emission of the dispersive density shock waves that carry away the excess of the initial impurity momentum, while locally the system remains in the same stationary state. In contrast, a heavy impurity with the same coupling constant relaxes differently and the regime of constant final velocity disappears. Furthermore, a fast heavy impurity exhibits damped velocity oscillations in time before reaching a stationary state. This process is accompanied by the oscillations of the local depletion of the boson density around the impurity, until their positions coincide and they continue the motion together. Decreasing the impurity-boson coupling or increasing the strength of repulsion between bosons, the oscillations get amplified. In the case of a heavy impurity with the mass bigger than the critical one, the ground state energy as a function of momentum exhibits cusps and metastable branches. We show that they manifest themselves by a soliton emission, a considerable slowing down of the relaxation, and a change of the impurity direction of motion with respect to the initial one.
Quantum Gases (cond-mat.quant-gas), Statistical Mechanics (cond-mat.stat-mech)
14 pages, 19 figures
Polaritonic Machine Learning for Graph-based Data Analysis
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-07-15 20:00 EDT
Yuan Wang, Stefano Scali, Oleksandr Kyriienko
Photonic and polaritonic systems offer a fast and efficient platform for accelerating machine learning (ML) through physics-based computing. To gain a computational advantage, however, polaritonic systems must: (1) exploit features that specifically favor nonlinear optical processing; (2) address problems that are computationally hard and depend on these features; (3) integrate photonic processing within broader ML pipelines. In this letter, we propose a polaritonic machine learning approach for solving graph-based data problems. We demonstrate how lattices of condensates can efficiently embed relational and topological information from point cloud datasets. This information is then incorporated into a pattern recognition workflow based on convolutional neural networks (CNNs), leading to significantly improved learning performance compared to physics-agnostic methods. Our extensive benchmarking shows that photonic machine learning achieves over 90% accuracy for Betti number classification and clique detection tasks - a substantial improvement over the 35% accuracy of bare CNNs. Our study introduces a distinct way of using photonic systems as fast tools for feature engineering, while building on top of high-performing digital machine learning.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Optics (physics.optics), Quantum Physics (quant-ph)
v1, to be updated
X-raying Mg0.2Co0.2Ni0.2Cu0.2Zn0.2O: disentangling elemental contributions in a prototypical high-entropy oxide
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-15 20:00 EDT
Maryia Zinouyeva, Martina Fracchia, Giulia Maranini, Mauro Coduri, Davide Impelluso, Nicholas B. Brookes, Lorenzo Grilli, Kurt Kummer, Francesco Rosa, Matteo Aramini, Giacomo Ghiringhelli, Paolo Ghigna, Marco Moretti Sala
We employ several X-ray based techniques, including X-ray diffraction, absorption and resonant inelastic scattering, to disentangle the contributions of individual chemical species to the structural, electronic and magnetic properties of high-entropy oxides. In the benchmark compound Mg0.2Co0.2Ni0.2Cu0.2Zn0.2O and related systems, we unambiguously resolve a sizable Jahn-Teller distortion at the Cu sites, more pronounced in the absence of Ni2+ and Mg2+, suggesting that these ions promote positional order, whereas Cu2+ ions act to destabilize it. Moreover, we detect magnetic excitations and estimate the strength of the interactions between pairs of different magnetic elements. Our results provide valuable insights into the role of the various chemical species in shaping the physical properties of high-entropy oxides.
Materials Science (cond-mat.mtrl-sci)
13 pages, 10 figures
Graphene Design with Parallel Cracks: Abnormal Crack Coalescence and Its Impact on Mechanical Properties
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-15 20:00 EDT
Suyeong Jin, Jung-Wuk Hong, Chiara Daraio, Alexandre F. Fonseca
Graphene is a material with potential applications in electric, thermal, and mechanical fields, and has seen significant advancements in growth methods that facilitate large-scale production. However, defects during growth and transfer to other substrates can compromise the integrity and strength of graphene. Surprisingly, the literature suggests that, in certain cases, defects can enhance or, at most, not affect the mechanical performance of graphene. Further research is necessary to explore how defects interact within graphene structure and affect its properties, especially in large-area samples. In this study, we investigate the interaction between two preexisting cracks and their effect on the mechanical properties of graphene using molecular dynamics simulations. The behavior of zigzag and armchair graphene structures with cracks separated by distances ($ W_\text{gap}$ ) is analyzed under tensile loading. The findings reveal that crack coalescence, defined as the formation of a new crack from two existing crack tips, occurs for lower values of the distance between cracks, $ W_\text{gap}$ , resulting in a decline in the strength of structures. As $ W_\text{gap}$ increases, the stress-strain curves shift upward, with the peak stress rising in the absence of crack coalescence. The effective stress intensity factor formulated in this study exhibits a clear upward trend with increasing $ W_\text{gap}$ . Furthermore, an increase in $ W_\text{gap}$ induces a transition in fracture behavior from crack coalescence to independent propagation with intercrack undulation. This shift in fracture behavior demonstrates a brittle-to-ductile transition, as evidenced by increased energy absorption and delayed failure. A design guideline for the initial crack geometry is suggested by correlating peak stress with the $ W_\text{gap}$ , within a certain range.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
35 pages, 9 figures, 5 tables
Sustainable Pre-reduction of Ferromanganese Oxides with Hydrogen: Heating Rate-Dependent Reduction Pathways and Microstructure Evolution
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-15 20:00 EDT
Anurag Bajpai, Barak Ratzker, Shiv Shankar, Dierk Raabe, Yan Ma
The reduction of ferromanganese ores into metallic feedstock is an energy-intensive process with substantial carbon emissions, necessitating sustainable alternatives. Hydrogen-based pre-reduction of manganese-rich ores offers a low-emission pathway to augment subsequent thermic Fe-Mn alloy production. However, reduction dynamics and microstructure evolution under varying thermal conditions remain poorly understood. This study investigates the influence of heating rate on the hydrogen-based direct reduction of natural Nchwaning ferromanganese ore and a synthetic analog. Non-isothermal thermogravimetric analysis revealed a complex multistep reduction process with overlapping kinetic regimes. Isoconversional kinetic analysis showed increased activation energy with reduction degree, indicating a transition from surface-reaction to diffusion-controlled reduction mechanisms. Interrupted X-ray diffraction experiments suggested that slow heating enables complete conversion to MnO and metallic Fe, while rapid heating promotes Fe- and Mn-oxides intermixing. Thermodynamic calculations for the Fe-Mn-O system predicted the equilibrium phase evolution, indicating Mn stabilized Fe-containing spinel and halite phases. Microstructural analysis revealed that slow heating rate yields fine and dispersed Fe particles in a porous MnO matrix, while fast heating leads to sporadic Fe-rich agglomerates. These findings suggest heating rate as a critical parameter governing reduction pathway, phase distribution, and microstructure evolution, thus offering key insights for optimizing hydrogen-based pre-reduction strategies towards more efficient and sustainable ferromanganese production.
Materials Science (cond-mat.mtrl-sci)
Resonant Valance Bond and Bethe Ansatz on Quasi-1D Lattices
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-15 20:00 EDT
The Hubbard model at $ U\to\infty$ has recently been shown to have resonant valence bond (RVB) ground states on the corner-sharing sawtooth and pyrochlore lattices in the dilute doping limit of a single vacancy. In an effort to further generalize those results, I study how the ground state is modified when not all corners are shared between two tetrahedra as in the quasi-1D lattices of a pyrochlore stripe, and how to approach the problem in the case of finite doping. Using a non-Abelian version of the flux inequality, the tetrahedron chain is shown to have degenerate RVB-like ground states. The Bethe ansatz (BA) is adapted to solve the sawtooth chain with spinless or spin-polarized fermions and multiple holons, which is the first example of applying BA to a quasi-1D lattice.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech), Superconductivity (cond-mat.supr-con), Mathematical Physics (math-ph), Quantum Physics (quant-ph)
Large Interconnected Thermodynamic Systems Nearly Minimize Entropy Production
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-15 20:00 EDT
Kyle J. Ray, Alexander B. Boyd
Many have speculated whether nonequilibrium systems obey principles of maximum or minimum entropy production. In this work, we use stochastic thermodynamics to derive the condition for the minimum entropy production state (MEPS) for continuous-time Markov chains (CTMCs), even far from equilibrium. We show that real nonequilibrium steady states (NESS) generally violate both the MINEP and MAXEP principles. However, through numerical sampling of large interconnected CTMCs, we find that as system size increases, the steady-state entropy production tends to converge toward the minimum. This suggests that large nonequilibrium systems may self-organize to make efficient use of thermodynamic resources, offering a nuanced perspective on the longstanding debate between MAXEP and MINEP.
Statistical Mechanics (cond-mat.stat-mech)
Strain and Correlation Modulated Magnetic Anisotropy and Dzyaloshinskii–Moriya Interaction in 2D H-FeTe$_2$
New Submission | Other Condensed Matter (cond-mat.other) | 2025-07-15 20:00 EDT
Dimple Rani, B. R. K. Nanda, Prasanjit Samal
In the ongoing research on two-dimensional (2D) ferromagnetic materials with strong intrinsic Dzyaloshinskii–Moriya interaction (DMI), most efforts have focused on doping, Janus engineering, or heterostructure formation to break inversion symmetry and enhance spin–orbit coupling (SOC). Here, we demonstrate that a pristine 2D material, monolayer H-FeTe$ _2$ , can naturally host robust DMI and magnetic anisotropy due to its intrinsic broken inversion symmetry and the strong SOC of Te atoms. We explore the effect of biaxial strain and electron correlation on H-FeTe$ _2$ using first-principles DFT+$ U$ calculations. We systematically investigate the Heisenberg exchange interaction, magnetic anisotropy, and DMI in the space spanned by strain and correlation. Our results reveal a distinct, non-monotonic strain dependence of both magnetic anisotropy energy (MAE) and DMI, including a strain-tunable crossover between in-plane and out-of-plane magnetic easy axes. A remarkable enhancement of the in-plane DMI is observed under the combined influence of strain and strong correlations, which is unusual for pristine 2D materials and suggests a favorable regime for spintronic this http URL, even in the absence of strain, H-FeTe$ _2$ exhibits finite DMI and considerable anisotropy, which is rare for a pure 2D material. Through these findings, we present H-FeTe$ _2$ as a unique pristine 2D system with robust and tunable spin interactions for exploring fundamental spin–orbit-driven magnetic phenomena.
Other Condensed Matter (cond-mat.other), Materials Science (cond-mat.mtrl-sci)
Topological phases and Edge states in an exactly solvable Gamma matrix model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-15 20:00 EDT
Akhil Pravin Furtado, Kusum Dhochak
We study the phases of an exactly solvable one dimensional model with $ 4-$ dimensional $ \Gamma-$ matrix degrees of freedom on each site. The $ \Gamma-$ matrix model has a large set of competing interactions and displays a rich phase diagram with critical lines and multi-critical points. We work with the model with certain $ Z_2$ symmetries and identify the allowed symmetry protected topological phases using the winding number as the topological invariant. The model belongs to the CII-class of the $ 10-$ fold classification and allows for integer values of the winding number. We confirm that the system also hosts localized zero energy Majorana edge modes, consistent with the integer value of the winding number of the corresponding phase. We further study scaling and universality behaviour of the various topological phase transitions.
Strongly Correlated Electrons (cond-mat.str-el)
Statistics of stochastic entropy for recorded transitions between ENSO states
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-15 20:00 EDT
We analyse the transitions between established phases of the El Niño Southern Oscillation (ENSO) by surveying the daily data of the Southern Oscillation Index from an entropic viewpoint using the framework of stochastic Statistical Physics. We evaluate the variation of entropy produced due to each recorded path of that index during each transition as well as taking only into consideration the beginning and the end of the change between phases and verified both integral fluctuation relations. The statistical results show that these entropy variations have not been extreme entropic events; only the transition between the strong $ 1999-2000$ La Niña to the moderate $ 2002-2003$ El Niño is at the edge of being so. With that, the present work opens a long and winding avenue of research over the application of stochastic Statistical Physics to Climate Dynamics.
Statistical Mechanics (cond-mat.stat-mech), Atmospheric and Oceanic Physics (physics.ao-ph), Data Analysis, Statistics and Probability (physics.data-an)
4 pages + 14 pages Supplemental Material
Phys. Rev. Lett. 133, 094201 (2024)
Closure of superstatistics
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-15 20:00 EDT
Plasmas and other systems with long-range interactions are commonly found in non-equilibrium steady states that are outside traditional Boltzmann-Gibbs statistics, but can be described using generalized statistical mechanics frameworks such as superstatistics, where steady states are treated as superpositions of canonical ensembles under a temperature distribution. In this work we solve the problem of inferring the possible steady states of a composite system $ AB$ where subsystem $ A$ is described by superstatistics and $ E_{AB} = E_A + E_B$ . Our result establishes a closure property of superstatistics, namely that $ A$ is described by superstatistics if and only if $ AB$ and $ B$ are also superstatistical with the same temperature distribution. Some consequences of this result are discussed, such as the impossibility of local thermal equilibrium (LTE) for additive subsystems in non-canonical steady states.
Statistical Mechanics (cond-mat.stat-mech)
Density Functional Theory Study of Th-doped LiCAF and LiSAF for Nuclear Clock Applications
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-15 20:00 EDT
Martin Pimon, Tobias Kirschbaum, Thorsten Schumm, Adriana Pálffy, Andreas Grüneis
Thorium-doped LiCaAlF$ _6$ and LiSrAlF$ _6$ (Th:LiCAF and Th:LiSAF) are promising crystals for a solid-state nuclear clock based on the 8 eV transition in $ ^{229}$ Th; however, their complex crystal structures complicate understanding the atomic arrangement of the thorium defects. In this work, density functional theory simulations are employed to systematically investigate these systems, including temperature-dependent effects and environmental conditions of fluorine saturation and deficiency. We investigated 20 distinct charge compensation schemes for each material, revealing lower defect formation energies in Th:LiSAF than in Th:LiCAF. This suggests that the former may attain a higher concentration of thorium nuclei. Furthermore, we calculated the electric field gradient for the lowest energy structure per compensation pathway. Our investigation shows that results previously reported in the literature apply only to a subset of experimental conditions.
Materials Science (cond-mat.mtrl-sci)