CMP Journal 2026-10-19
Statistics
Nature: 1
Nature Materials: 1
Nature Physics: 2
Nature Reviews Materials: 2
Nature Reviews Physics: 1
arXiv: 86
Nature
Cortex-wide imaging in naturally behaving mice with 1-gram wireless mesoscopes
Original Paper | Biomedical engineering | 2026-10-18 20:00 EDT
Yuanlong Zhang, Angran Li, Lekang Yuan, Mingrui Wang, Weihao Zhao, Zhenbo Wang, Boyang Zang, Yangxuan Zhou, Tao Yu, Lin Gao, Yu Wu, Rongkang Zhu, Mengyi Tian, Kun Li, Jiamin Wu, Pu Dai, Qionghai Dai
Revealing how distributed cortical circuits coordinate behavior in freely moving animals remains a central challenge in systems neuroscience, constrained by limited fields of view, low throughput, and the tethering required by current miniaturized microscopes1-4. Here, we present Airscope, a wireless mesoscope delivering 4 μm lateral resolution across a 6 mm field of view at 12.5 Hz, weighing 1.0 gram. An aspheric-lens design achieves a 2.84× shorter total track length than previous miniaturized microscopes1,2,5,6 while matching the neuron yield of benchtop one-photon mesoscopes; a tailored wireless link supports cable-free calcium imaging from >8,500 neurons per animal (25‑fold increase). Paired with a zero-shot behavior analyzer, Airscope enables cortical imaging across rich behavioral conditions, including room-scale enriched arenas, swimming assays, and multi-organ implantation, with concurrent recording from multiple animals. Using Airscope, we demonstrate versatile applications of untethered cortical imaging across diverse behavioral paradigms. We identify cortical activity patterns across multiple dorsal regions that correlate with behavioral signatures of social dominance, and show dorsal-cortical population activity prospectively decodes competition outcomes across paired animals. We observe reward-location-associated cortical activity patterns during maze exploration, and characterize Granger-causal influence from spinal cord to cortex during fear conditioning, enabled by simultaneous brain-spinal recordings. By uniting large-scale, cellular-resolution recording with unconstrained behavior, Airscope makes naturalistic, multi-animal cortical recording experimentally practical, and provides a broadly accessible technology for systems neuroscience.
Biomedical engineering, Engineering
Nature Materials
Bioresorbable metal-free molecular magnets enable untethered organ monitoring
Original Paper | Sensors and biosensors | 2026-10-18 20:00 EDT
Yizhang Wu, Zhang Yue, Sicheng Xing, Dingyi Yang, Jie Wang, Yihan Liu, Harrison Cohen, Lucy Liu, Qizhang Jiao, Zifeng Li, Hanad Ali, Chaya Perera, Torsten Peter Vahl, Lauren Sharan Ranard, Zhibo Zhang, Andrew J. Einstein, Anran Zhang, Stephen Dashnaw, Yiwen Huang, William Pak, Ziheng Guo, Gongkai Yuan, Siyuan Liu, Alexander Romanov, Sen Yang, X. S. Wu, Yong Wang, Ke Cheng, Wubin Bai
Metal-free molecular magnets differ from conventional magnetic devices that predominantly rely on metallic magnets as these metal-free materials may offer biocompatibility and bioresorbability. However, existing molecular materials lack the ferromagnetic strength required for high-fidelity sensing at clinically relevant tissue depths. Here we introduce a bioresorbable metal-free molecular magnet derived from graphitic carbon nitride, combining metallic-level ferromagnetism with full bioresorbability. De-nitrogenation creates spin centres coupled through a reconstructed π-σ conjugated framework, conferring robust spontaneous magnetization that remains stable under physiological conditions. Integrated with poly(lactic-co-glycolic acid) and silk fibroin, the material forms catheter-deliverable epicardial patches for cardiac tracking and can also be dispersed in injectable hydrogels for organ-scale sensing, including the three-dimensional reconstruction of localized hepatic pathologies. Coupled with a skin-interfaced Hall array, this magnetic sensing architecture provides the continuous, untethered monitoring of multi-organ dynamics, robust against motion artifacts and tissue impedance. In porcine models, it facilitates the continuous assessment of ejection fraction over 4 weeks, followed by benign bioresorption. Benchmarked against standard-of-care echocardiography, this approach delivers clinical-grade trajectories, supporting longitudinal, infrastructure-independent physiological monitoring.
Sensors and biosensors, Ferromagnetism, Biomedical engineering, Magnetic properties and materials, Biomedical materials
Nature Physics
A liquid-crystal analogue of the skyrmion Hall effect
Original Paper | Fluid dynamics | 2026-10-18 20:00 EDT
Rodrigo C. V. Coelho, Hanqing Zhao, Guilherme N. C. Amaral, Ivan I. Smalyukh, Margarida M. Telo da Gama, Mykola Tasinkevych
Topology provides a unifying framework across disciplines, ranging from particle physics and cosmology to condensed-matter systems. In condensed matter, one of its most striking manifestations is the skyrmion Hall effect, where skyrmions–emergent spin configurations characterized by a conserved topological charge–acquire a transverse velocity under driving. Recent advances have revealed that chiral liquid crystals host a wide variety of topological solitons, including torons and skyrmion tubes. Here we show that such solitons exhibit a Hall-like response under shear flow, undergoing a transverse drift away from the shear direction. Our theoretical analysis predicts a weak net transverse mass flow whose magnitude scales as the cube of the shear rate. However, tracer-particle experiments and numerical simulations show that the solitons do not behave as passive tracers of this flow: their transverse motion is much stronger, and in simulations, it occurs opposite to the net transverse mass current. A liquid-crystal analogue of the Thiele equation provides a simple physical framework that highlights the central role of flow vorticity in the effect. These results establish a liquid-crystal analogue of the skyrmion Hall effect and open pathways for microfluidic technologies that exploit soft topological solitons as functional building blocks.
Fluid dynamics, Liquid crystals
Evidence for spin-fluctuation-mediated superconductivity in electron-doped cuprates
Original Paper | Superconducting properties and materials | 2026-10-18 20:00 EDT
C. M. Duffy, S. J. Tu, Q. H. Chen, J. S. Zhang, A. Cuoghi, R. D. H. Hinlopen, T. Sarkar, R. L. Greene, K. Jin, N. E. Hussey
In conventional, phonon-mediated superconductors, the transition temperature and the linear-in-temperature normal-state scattering rate are linked through the electron-phonon coupling strength. In cuprate high-temperature superconductors, no equivalent relationship between critical temperature and electron-boson coupling has been identified. Here we highlight such a link with electrons scattering off commensurate antiferromagnetic spin fluctuations of variable strength. We use d.c. resistivity and high-field magnetoresistance to extract the scattering rate in electron-doped La2-xCexCuO4 as a function of doping. We reveal a highly anisotropic inelastic component to the scattering rate whose magnitude diminishes markedly as doping increases. The correlation we highlight between the strength of scattering and the critical temperature then identifies low-energy spin fluctuations as the primary pairing glue in electron-doped cuprates. The contrasting magnetotransport behaviour in hole-doped cuprates suggests that the higher critical temperature in those materials cannot be attributed solely to an increase in the coupling strength to the antiferromagnetic fluctuations. The success in modelling La2-xCexCuO4 reinforces the notion that resolving the origin of high-temperature superconductivity in hole-doped cuprates may require more than a simple extension of the Bardeen-Cooper-Schrieffer theory.
Superconducting properties and materials, Electronic properties and materials
Nature Reviews Materials
Cost-driven strategies towards industrially manufacturable perovskite photovoltaics
Review Paper | Solar cells | 2026-10-18 20:00 EDT
Ziyang Zhang
(张子扬), Yingming Liu
(刘英明), Zhenzhen Qin
(秦臻臻), Mengjiong Chen
(陈锰炯), Yanbo Wang
(王言博), Liyuan Han
(韩礼元)
With power conversion efficiencies exceeding 27%, perovskite solar cells (PSCs) are transitioning from laboratory-scale efficiency-driven research to a focus on large-scale deployment. At this stage, manufacturing cost is emerging as a key constraint governing the industrial competitiveness of PSCs. The manufacturing cost of PSCs (approximately US$0.3-0.6 W-1) remains much higher than that of mature crystalline silicon solar cells (approximately $0.1 W-1); therefore, it is essential to incorporate cost considerations into the future technological development of PSCs. In this Review, we discuss advances in PSC research from a cost-driven perspective, organized into three dimensions: enhancing manufacturing yield by addressing material reliability and process tolerance, reducing material costs by rethinking material selection and device architectures alongside material recycling strategies, and simplifying fabrication by alleviating dependence on controlled environments, specialized equipment and energy-intensive processing. Finally, we discuss how cost-oriented principles can be incorporated into PSC research and development while maintaining competitive device performance to facilitate their transition from laboratory studies to commercially viable photovoltaic technologies.
Solar cells
Water serves as a charge-transfer medium for ultrafast aqueous batteries
Review Paper | Chemical physics | 2026-10-18 20:00 EDT
Jie Chen
(陈杰), Yuhang Dai
(戴宇航), Ruihu Lu
(陆瑞虎), Tianfeng Qin
(秦天锋), Ruwei Chen
(陈儒维), Hang Yang
(杨航), Yuqi Li
(李钰琦), Yonggang Wang
(王永刚), Guanjie He
(何冠杰)
Charge storage in aqueous batteries is commonly understood through an ion-centric picture, in which metal ions or pre-existing protons transport and compensate charge. However, conventional metal-ion diffusion and proton insertion do not fully account for seconds-level kinetics, strong cation-electrode specificity and experimentally detectable proton signatures observed at the low equilibrium proton concentrations in aqueous metal-ion batteries. In this Perspective, we propose that interfacial water can serve as a charge-transfer medium under certain conditions, with ultrafast kinetics arising from the cleavage and reorganization of water at electrode-electrolyte interfaces. In this framework, water-derived protons provide charge compensation through insertion processes, and the formation and relaxation of short-lived water-derived intermediates reflect the activation of water cleavage. We outline the working principles of ultrafast charging behaviour mediated by interfacial water and its positioning among known fast charging pathways in aqueous batteries, the physical origin and tunability of interfacial water cleavage, and transient spectroscopic tools capable of resolving the evolution of short-lived water-derived intermediates. Finally, we discuss the implications of this interfacial-water-centred view for electrode and device design and for high-power aqueous energy-storage applications.
Chemical physics, Batteries
Nature Reviews Physics
Tipping points in complex ecological systems
Review Paper | Theoretical ecology | 2026-10-18 20:00 EDT
Alan Hastings, Sergei Petrovskii, Valerio Lucarini, Andrew Morozov
In the modern physics of complex systems, a topic receiving increasing attention is tipping points. These are usually thought of as states of a system in which changing parameters slightly can lead to a large, and generally abrupt and irreversible, change in properties. There exists a number of different mathematical structures that can show this behaviour, and the one that was originally used (nowadays often referred to as the bifurcation-induced tipping) is just one of many. Different preconditions and/or different levels of details included into the model, reflecting also different environmental forcing, can lead to various tipping mechanisms. Furthermore, in a spatially extended system and/or a system with multiple scales, different parts can react to a change in environmental conditions differently or at a different time, interacting with each other to create a tipping cascade. In this Review, using ecosystems as a paradigm of complex nonlinear open systems, we survey the progress made in tipping point science over the past 15 years and identify gaps in the knowledge.
Theoretical ecology, Climate-change ecology, Phase transitions and critical phenomena
arXiv
Universal link between structural relaxation and self-diffusion in simple supercooled liquids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-19 20:00 EDT
Mingyu Zhu, Xinyu Chang, Licun Fu, Yiming Zheng, Lijin Wang
Despite a vigorous effort, a comprehensive and satisfactory understanding of the dynamics underlying the glass transition in finite-dimensional systems has not yet emerged. One key hallmark of supercooled liquids approaching the glass transition is the breakdown of the classical Stokes-Einstein (SE) relation, manifested as the decoupling between the self-diffusion coefficient and structural relaxation time, commonly described by a fractional SE relation. Whether and how the fractional SE exponents vary remains an ongoing debate, even for the simplest supercooled liquids. In this work, we numerically establish a universal relation between the self-diffusion coefficient and structural relaxation time by introducing characteristic scales that are revealed under the condition of constant dynamical heterogeneity. Moreover, this universal relation could also capture literature data for supercooled water and silica. Remarkably, we find that the fractional SE exponent is invariant across various supercooled liquids studied spanning a wide range of fragility, thereby challenging the prevailing view that the fractional SE exponent is correlated with fragility. Our study demonstrates that investigating dynamical heterogeneity yields more valuable insights into understanding glassy dynamics than expected.
Soft Condensed Matter (cond-mat.soft)
9 pages, 4 figures
Noise-Induced Restoration of Entropy Concavity Near Gaussian Equilibrium
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-19 20:00 EDT
We study a quantitative form of noise-induced restoration of entropy concavity for one-dimensional nonequilibrium states relaxing toward a Gaussian thermal equilibrium. A partially thermalized state is modeled by $ X_q=\sqrt q,X+\sqrt{1-q},G$ , where $ G$ is Gaussian equilibrium noise and $ q$ is the retained signal fraction. For two independently prepared copies we ask when the entropy of the mixed state $ h(\sqrt{1-t},X_q+\sqrt t,Y_q)$ is concave in the mixing parameter. The problem is motivated by entropy geometry along Ornstein–Uhlenbeck/Fokker–Planck relaxation, where the relative score is the nonequilibrium thermodynamic force and relative Fisher information is entropy-production rate. We derive an exact symmetric endpoint-curvature formula, separating a nonnegative Ornstein–Uhlenbeck restoring term from a fourth-cumulant correction, and extend it to nonsmooth generalized-Gaussian states $ e^{-a|x|^p}$ for $ p>3/2$ . For half thermalization of a symmetric log-concave input, posterior-variance identities give a quantitative outer-region theorem confining any endpoint obstruction to two explicitly bounded near-equilibrium sectors. We also give spectral and MMSE reformulations of the auxiliary inequality $ A\ge2\delta$ , prove it in an explicit nonlinear neighborhood of Gaussian equilibrium, and show how it sharpens the endpoint bounds. The main all-mixing result concerns the leading symmetric non-Gaussian Hermite mode: for $ p_a=\phiG(1+a\He_4)$ , $ 0<a\le10^{-2}$ , we prove strict entropy concavity for every $ 0<t<1$ and every $ 0<q\le5/8$ , hence throughout the currently unresolved symmetric range $ 0<q\le4/7$ for this explicit nonequilibrium family. Numerical searches over broader log-concave families are reported only as supporting evidence.
Statistical Mechanics (cond-mat.stat-mech), High Energy Physics - Theory (hep-th)
4 Figures
QMBL: the Quantum Many-Body Leaderboard. A live record of published ground-state energies for lattice Hamiltonians
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-19 20:00 EDT
Tristan Zerweck, Juan Carrasquilla
In condensed matter physics, scientists explore phase diagrams of matter through various methods (analysis, numerics, experiment) and achieve consensus when enough methods agree. The quality of variational results for quantum many-body ground states is mainly judged by energy values and respective errors. Here, we present QMBL, the Quantum Many-Body Leaderboard (this https URL), serving as the energy layer of the scientific consensus. It is a maintained, interactive record of published ground-state energies for lattice Hamiltonians. The latest release v0.4.0 holds 1434 energies on 395 instances of six model families and collects all of the community’s efforts into one view. Of those instances 153 have no exact solution and any new record serves as a direct improvement to an open science problem. They are the targets of a companion benchmark, QMBL: Open Problems.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
2 pages, 2 figures. Data: this https URL leaderboard: this https URL
Thermodynamics of coupled electromagnetic and mass fields
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-19 20:00 EDT
We formulate a unified thermodynamic framework for chemical, mechanical, and electromagnetic transport by extending the Gibbs–Duhem relation to include kinetic free-energy contributions associated with material and field motion. The resulting kinetic Gibbs–Duhem relation establishes a thermodynamic connection between free-energy variations, generalized chemical potentials, pressure, and transport momentum, while preserving the invariance of the system free energy under changes of reference frame. Within a Lagrangian formulation of free-energy evolution, the relation provides a common structure for diffusion, momentum transport, and electromagnetic dynamics. For nonuniform chemical systems, the framework recovers the coupling between Cahn–Hilliard dynamics and the Korteweg stress arising from composition gradients. Its extension to electromagnetic systems incorporates electric, magnetic, charge, and mechanical contributions into the same thermodynamic formulation, yielding a unified description of electromagnetic and momentum evolution. The framework further separates dissipative from nondissipative transport and establishes a common thermodynamic form for mechanical and electromagnetic propagation. In the isentropic limit, the characteristic propagation velocity is determined by the derivative of the thermodynamic pressure with respect to density, yielding the speed of sound for mechanical systems and the speed of light for electromagnetic systems. These results show that kinetic contributions can be incorporated consistently into the Gibbs–Duhem framework, providing a common thermodynamic basis for coupled chemical, mechanical, and electromagnetic transport without introducing separate thermodynamic principles for each mechanism.
Statistical Mechanics (cond-mat.stat-mech)
Visualizing surface-reaction-driven chloride migration and cascading failure in sulfide solid electrolytes
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-19 20:00 EDT
Xiaoya He, Haoran Zhang, Xinyang Yue, Hang Liu, Zian Mao, Jialong Wang, Min Liu, Shufen Chu, Liwei Chen, Zhaoxin Yu, Xi Liu, Chuying Ouyang, Ziyang Ning, Yujun Xie
Moisture instability of sulfide solid electrolytes limits practical use in all-solid-state batteries. Spatially resolving gas–solid reactions during moisture exposure remains challenging. Here, cryogenic four-dimensional scanning transmission electron microscopy (cryo-4D-STEM) maps nanoscale degradation in low- and high-Cl argyrodite electrolytes, Li(6)PS(5)Cl and Li({5.5})PS({4.5})Cl({1.5}). Li(6)PS(5)Cl undergoes predominantly surface-localized degradation that progressively extends inward, whereas Li({5.5})PS({4.5})Cl({1.5}) exhibits rapid interior amorphization accompanied by outward chloride redistribution. Density functional theory calculations indicate a lower chloride-migration barrier along the modeled pathway in the higher-Cl composition, while chloride removal and vacancy formation distort the PS(_4^{3-}) framework and may destabilize the lattice. Surface treatment suppresses detectable large-scale chloride segregation and improves moisture tolerance, retaining 99.9% of the capacity measured at the start of 0.33 C cycling after 150 cycles. These results identify chloride redistribution as a key process in degradation propagation and suggest a route toward moisture-tolerant solid-state batteries.
Materials Science (cond-mat.mtrl-sci)
Synergistic Self-Driven Nanoconfinement and Dynamical Heterogeneity in Deeply Supercooled “No Man’s Land” Water
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-19 20:00 EDT
The 150–235 K no man's land'' (NML) of deeply supercooled water is a highly debated regime where rapid crystallization hinders experimental observation of the hypothesized liquid-liquid phase transition. Using TIP4P/2005 molecular dynamics simulations, we uncover a structurally and dynamically heterogeneous state at ambient pressure that exhibits novel physical features. Our results demonstrate that this low-density state ($ \rho \approx 0.925$ g/cm$ ^3$ ) is a unique supercooled liquid, distinct from both glassy and spinodal states. Specifically, it emerges as a stable, structurally arrested phase driven by a self-generated soft skeleton’’ of nanoclusters. This network forms an intrinsic nanoporous structure that imposes nanoconfinement on the remaining fluid, proving that NML confinement can be an entirely self-driven phenomenon. Finally, we resolve the temperature-dependent, nonlinear behavior of density and compressibility, highlighting a structurally driven anomaly that clarifies the thermodynamics of deep supercooling. Collectively, this work provides a transformative structural framework for understanding the anomalous nature of water within the NML.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
15 pages, 7 figures + supplement, under review
Semiclassical Analysis of Wave Dynamics via Wigner Transforms: Applications to the Quantum Harmonic, Anharmonic, and Dirac Oscillator
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-19 20:00 EDT
In this Master’s thesis, we give a pedagogical introduction to the semiclassical analysis of wave dynamics in single-band and multi-band systems. We show how the semiclassical evolutions of Wigner functions can approximate the dynamics of wave packet centers and wave packet deformations. Three systems of increasing complexity are considered: the quantum harmonic oscillator and the quantum anharmonic oscillator as single-band systems, and the Dirac oscillator as a two-band system. We explain the origins of the first-order semiclassical corrections (Moyal, Littlejohn-Flynn, and Berry) in the equations of motion and examine their effects on predictive accuracy.
Another focus is set on the conditions for validity of the semiclassical analysis. For both the quantum anharmonic and the Dirac oscillators, a dimensionless parameter controlling the accuracy of the approximation is identified. In multi-band systems, the formalism applies only to states within a single adiabatic subspace, which, for the Dirac oscillator, corresponds to an energy branch. This motivates the construction of single-branch almost coherent states: approximately Gaussian wave packets formed by superpositions of states from a single energy branch. Their centers undergo oscillations with an aperiodic envelope. These states enable comparison between semiclassical Wigner function evolution and the commonly used Sundaram-Niu formalism. We show that semiclassical Wigner function evolution captures deformation-related dynamics, including the initial decay of oscillations, which the Sundaram-Niu formalism cannot describe by construction.
Additionally, exact quantum evolution reveals partial relocalization of these single-branch almost coherent states, a phenomenon that cannot be captured by the semiclassical evolution.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
Probing nonequilibrium transport and density profiles in tilted interacting fermion chains with local reservoirs
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-19 20:00 EDT
Andrea Nava, N. Aucar Boidi, Reinhold Egger, Karen Hallberg, C. R. Proetto
We investigate how local particle reservoirs can probe transport and density profiles in tilted spinless fermion chains with nearest-neighbor interactions. Using finite-chain Lindblad calculations with particle injection and extraction at opposite ends, we define a threshold-dependent transmission range from the stationary current as the chain length is varied. This range decreases with increasing tilt and follows the trends of the equilibrium density-crossover width in the parameter regimes studied. Interactions can enhance transmission by compensating field-induced energy costs, whereas strongly polarized configurations suppress transport. A third, weakly coupled extraction reservoir provides a complementary spatial probe: its current is exactly proportional to the local occupation in the presence of the probe, and the normalized current approaches the unperturbed nonequilibrium density as the probe coupling vanishes. We illustrate the detection of staggered density modulations and show that bulk densities can continue to relax after boundary currents have nearly stabilized. These protocols connect current measurements to spatial transmission and density structure in driven interacting chains.
Strongly Correlated Electrons (cond-mat.str-el)
22 pages, 13 figures
Anyon bound states in MoTe$_2$ Fractional Chern Insulators
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-19 20:00 EDT
Binding anyons to optically active excitons offers a route to manipulate fractional excitations and reveal the internal spatial structure of anyons. We establish the formation of anyon bound states between a mobile dipolar exciton and an $ e/3$ quasihole in a twisted bilayer MoTe$ _2$ fractional Chern insulator. Using exact diagonalization of a continuum-based interacting model, we identify a regime of meV-scale binding and strong exciton-quasihole entanglement controlled by exciton mobility and the distance between the exciton and the FCI. Spatial correlations resolve a localized depletion core carrying approximately $ e/3$ charge around the exciton, providing a real-space characterization of the bound state. Beyond its fractional charge, the quasihole exhibits a moiré-induced octupolar structure. Interlayer tunneling anisotropy strongly deforms this structure while leaving the enclosed charge nearly unchanged, linking the internal profile of the anyon to the underlying electronic quantum geometry. These findings establish conditions for robust exciton-anyon binding in moiré heterostructures and show how these composites provide access to properties of fractional excitations beyond their total charge.
Strongly Correlated Electrons (cond-mat.str-el)
6 pages, 4 figures
Fractional Chern insulators and composite Fermi liquids vs. charge order in twisted MoTe$_2$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-19 20:00 EDT
Enrique Aguilar-Méndez, Glenn Wagner
The bandstructure of twisted MoTe$ _2$ around 3.7$ ^\circ$ consists of spin-valley locked Chern bands with a bandwidth that is smaller than the interaction scale. As such, the strongly correlated phases familiar from Landau levels can be realized: Quantum Hall states, composite Fermi liquids and charge order. These states have in common that they are all favoured by strong interactions, however changing the quantum geometry and topology of the bands as well as their bandwidth via the displacement field and twist angle tilts the balance between them. We provide a comprehensive exact diagonalization analysis of the competition between these states and in particular elucidate the nature of the charge order at fillings $ \nu=-\frac14,-\frac13,-\frac12,-\frac23$ . Furthermore, we analyze the effect of band mixing by going beyond a single band per valley. This effect of band mixing is crucial for reconciling the numerical phase diagrams with experimental observations.
Strongly Correlated Electrons (cond-mat.str-el)
Comment on “Skyrmion Hall Effect in Altermagnets”
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-19 20:00 EDT
Nicolai Timon Bechler, Jan Masell
In their Letter, Jin et al. [Phys. Rev. Lett. 133, 196701 (2024)] predict a transverse velocity $ v_y$ for skyrmions driven by spin-transfer torque (STT), known as skyrmion Hall effect (SkHE), in d-wave altermagnets. Usually, the SkHE emerges from the skyrmion’s topological charge which here cancels between sublattices. Instead, Jin et al. attribute the SkHE to the dimensionless quadrupole tensor $ A_{ij}$ . The result in their Eq. (12) is fitted to micromagnetic simulations, yielding a finite value for $ A_{xy}$ . However, via the divergence theorem, $ A_{ij}$ simplifies to a boundary integral that vanishes for a sufficiently smooth and localized texture. In this Comment, we substantiate our claim from Ref. [2] that the numerically observed SkHE by Jin et al. for a micromagnetic model with standard Zhang-Li STT in the individual sublattices is merely a discretization artefact.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
Comment on arXiv:2407.03959 [Phys. Rev. Lett. 133, 196701 (2024)], 2 pages, 1 figure
Attraction from repulsion in an interacting Chern band: chiral superconductivity, generalized Hall crystals, and competing fractional Chern insulators
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-19 20:00 EDT
Fabian Pichler, Clemens Kuhlenkamp, Ashvin Vishwanath, Michael Knap
Experiments realizing strong interactions in partially filled Chern bands have observed fractional Chern insulators (FCIs), superconductors, and topological crystals in close proximity. Yet the microscopic relation between them remains poorly understood. Here, we use tensor network simulations to study repulsively interacting spinless fermions in a tunable topological band of the checkerboard lattice. We characterize the competing phases and identify key features of the experimental phenomenology. FCIs from the Jain sequence transition into chiral p-wave superconductivity both below and above half filling as the band dispersion is enhanced. By contrast, at half filling, a generalized Hall crystal with quantized Hall conductance and a doubled unit cell forms for sufficiently strong coupling. Surprisingly, a weak-coupling approach starting from a metallic parent state captures the nature of both ordered phases at intermediate coupling. We find that fluctuations in the metal generate longer-range attraction, which we analyze within the random-phase approximation. This approach captures the pairing symmetry as well as the radial form factors of the Cooper pairs, and incorporating this attraction into Hartree-Fock selects the observed Hall crystal. Together, these results identify fluctuation-induced attraction from repulsion as a common microscopic ingredient of ordering, while our tensor network computations establish the direct competition of both phases with FCIs.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
16 pages (including appendices), 7+8 figures
Quantum-interference correction to conductivity in disordered electronic bands with non-uniform quantum geometry
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-19 20:00 EDT
Yip Chun Wong, Asimpunya Mitra, Yong Baek Kim
Weak localization in two-dimensional disordered electron systems originates from constructive interference between time-reversed scattering paths, giving rise to a logarithmically divergent quantum-interference correction to the dc conductivity. This behavior is generally suppressed when time-reversal symmetry (TRS) is broken. In this study, using a band-projected framework motivated by spin- and valley-polarized rhombohedral $ N$ -layer graphene (RNG), we show that nonuniform quantum geometry can qualitatively modify quantum-interference corrections to dc transport. In particular, continuously tuning the quantum geometry can change the sign of the conductivity correction, corresponding to a crossover between localization and antilocalization tendencies. Remarkably, at special values of the parameter controlling the quantum geometry, weak-localization (WL) or weak-antilocalization (WAL) can re-emerge despite broken microscopic TRS. At these special points, the orbital structure of the Bloch states gives rise to an emergent antiunitary symmetry that protects a gapless Cooperon mode and restores the logarithmically divergent quantum-interference correction characteristic of WL or WAL. Our results establish nonuniform quantum geometry as a mechanism for controlling quantum interference and electron localization in multiorbital electronic systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
26 pages, 8 figures
Magnetic flux ring splitting near a Navier-Stokes singularity
New Submission | Other Condensed Matter (cond-mat.other) | 2026-10-19 20:00 EDT
OpenAI reports a forced Navier-Stokes flow that becomes singular in finite time, raising the question of its physical consequences. Magnetic reconnection offers a test through the splitting and merging of flux structures. We use resistive magnetohydrodynamics to simulate a magnetic ring driven by an imposed, regularized flow that reproduces the geometry and scaling of the collapsing core. At the nominal singular time, we remove the imposed drive and allow the system to evolve freely. Reconnections before and after release split the ring into two or more daughter rings through bifurcations of the poloidal flux function, with Lorentz feedback selecting the bifurcation type. Unequal winding by the swirl above and below the midplane produces asymmetric toroidal magnetic stresses, unfolding the kinematic pitchfork-like transition into a fold. For single-island splits, the cusp normal form predicts the asymmetry of the daughter rings without adjustable parameters. Three-dimensional simulations retain the splits and merger, confirming that approach to hydrodynamic blow-up can trigger magnetic restructuring.
Other Condensed Matter (cond-mat.other), Fluid Dynamics (physics.flu-dyn)
3 movies
Valley-Selective Transport through Structural Domain Walls in Rhombohedral Graphene Quarter Metals
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-19 20:00 EDT
Vo Tien Phong, Pablo San-Jose, Bing Cheng, Zhengguang Lu, Elsa Prada, Long Ju, Eugene Mele, Cyprian Lewandowski, Francisco Guinea
Domain walls separating quarter metals with opposite valley polarizations have recently been imaged in rhombohedral graphene multilayers. Depending on their formation mechanism, these walls respond in distinct ways to external magnetic probes. Therefore, understanding their behaviors is critical to the interpretation of experimental results. In this work, we examine domain walls formed from strain-induced one-dimensional structural defects that separate domains with complementary rhombohedral stacking orders. We show that while transport across such domain walls is controlled by the valley degree of freedom, the coupling to a magnetic field is dictated by the momentum-space chirality encoded in the Hamiltonian. As a consequence, structural domain walls are rendered electronically opaque by an applied magnetic field, while intrinsic domain walls formed by spontaneous valley symmetry breaking are unstable in the presence of such an ordering field and can be eliminated. This dichotomy allows the two types of domain walls to be distinguished in a magnetotransport experiment.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Comments are welcome and appreciated! 7+8 pages; 4+4 figures
Bulk-Defect Correspondence in Algebraic Classical Spin Liquids
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-19 20:00 EDT
Local constraints in algebraic classical spin liquids give rise to singular momentum-space correlations. This so called pinch-point singularity carries a momentum-space winding number that determines the low-energy structure of the algebraic spin liquid. We show that nonmagnetic vacancies in two dimensions reveal this topological invariant in the real-space winding of the surrounding spin textures. Under explicit conditions, we prove this bulk-defect correspondence for rank-$ n$ $ \mathrm{U}(1)$ spin liquids and verify it numerically for the Coulomb spin liquids of the kagome and checkerboard lattices and the rank-2 $ \mathrm{U}(1)$ spin liquid of the honeycomb-snowflake model. In this way we show that vacancies can be used as general probes for distinguishing the emergent gauge theories of strongly correlated classical disordered magnets.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech)
Segregation of cylindrically confined cross-linked polymers
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-19 20:00 EDT
James M. Polson, Tyler M. Dickieson, Matthew R. O’Connell
Entropic repulsion between polymer chains under confinement in a narrow channel tends to induce segregation. Recent computer simulation studies have provided indirect evidence that internal cross linking of ring polymers, which creates internal loops, enhances the entropic force. Such topologically enhanced entropic forces are thought to contribute to the segregation of bacterial chromosomes during replication. In this study, we use Monte Carlo computer simulations of a coarse-grained hard-sphere chain model to measure the configurational free energy of two cross-linked ring polymers as a function of the separation distance between the polymer centers of mass. We examine the effects of varying the polymer architecture as well as the confinement dimensions on the free energy functions. In addition, we use the results to make a quantitative assessment of the accuracy of a simple theoretical model built on the de Gennes blob model that has been used in past studies to estimate the overlap free energy of confined polymers. Consistent with indirect evidence from previous simulations studies of segregation dynamics, we find that increasing the number of internal loops and selecting binding sites to enforce a side-loop configuration tends to increase the overlap free energy. Analysis of the whole-polymer and interior-loop extension and overlap lengths reveal a sequence of overlap domains that explain subtle variations in the free energy functions. For all architectures examined, the theoretical model provides a reasonably accurate prediction for how the cross linking and degree of confinement affects the free energy, with quantitative discrepancies comparable to those observed in previous studies using linear polymers and ring polymers without cross links.
Soft Condensed Matter (cond-mat.soft)
17 pages, 10 figures
A Comprehensive Survey of Crystal Structural Prototypes: Construction, Classification, and Applications
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-19 20:00 EDT
Jianjun Hu, Ying Feng, Rongzhi Dong, Jeffrey Hu, Remy Rogers, Dipannoy Gupta
Crystal structural prototypes describe recurring atomic arrangements across chemically distinct materials. Prototype libraries are built through crystallographic curation, standardization, geometric matching, local-environment clustering, and periodic-graph analysis, and support chemical substitution, derivative enumeration, high-throughput screening, structure solution, crystal structure prediction (CSP), and generative design. This survey compares methods by the structural information they retain and the equivalence rules they impose, distinguishing crystallographic structure types, geometric realizations, chemistry-anonymous topologies, and chemical decorations. We review curated and automatically extracted prototype libraries (AFLOW, CSPD, LAE-ICSPD, EMFDTW, TYPIX, ICSD structure types), their source databases, and algorithms for assigning family membership. A GraphID-based analysis of samples from ICSD, the Materials Project, OQMD, and LeMat shows that the 100 most frequent families in each sample cover 30 to 67 percent of analyzed structures, while 72 to 82 percent of observed families are singletons. The GraphIDs of up to 76 percent of structures change when the neighbor tolerance is varied. In our comparison of 12 generative CSP models, template retrieval achieves the highest top-1 success rate. Removing a reduced-stoichiometry class from training introduces new failures in 50 to 78 percent of the test structures of that class, which measures sensitivity to stoichiometric coverage, not generalization to unseen prototypes. We relate these findings to earlier statistics of structure types, space groups, and periodic nets, and to protein-fold coverage studies. We propose independent-database coverage measurements, discovery-rate analyses, and family-held-out tests to assess how prototype reuse affects prediction accuracy, generalization, and novelty.
Materials Science (cond-mat.mtrl-sci)
41 pages
Zeta potential of magnetic-field-controlled silver nanoparticles
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-19 20:00 EDT
Magnetic-field-dependent nanoparticle size does not by itself determine zeta potential, which also depends on interfacial charge, electrolyte screening, and the location of the slipping plane. We extend the sphere-packing description of silver nanoparticles by distinguishing the structural surface, the effective charge plane, and the hydrodynamic slipping plane. The model uses structural radii of \SI{20}{nm} and \SI{5}{nm} at zero field and \SI{250}{mT}, with reported zeta potentials of \SI{-13.2}{mV} and \SI{-10.0}{mV}. Effective charge is related to the defective-shell atom count. For field-independent interfacial parameters, the linear response without additional charge weighting decreases with decreasing radius. Its normalized form depends on three electrokinetic lengths through only two sums, preventing their independent determination from a field-dependent zeta curve. At ((\kappa^{-1},t_{\mathrm{lig}},\delta_{\mathrm{slip}})=(3,0,1),\mathrm{nm}), nonlinear Poisson–Boltzmann electrostatics changes the fitted shell coefficient from 0.316 to 0.299. Constant total charge still predicts an increase in zeta magnitude, opposite to the observed trend in the evaluated scenarios. Independently calibrated shell and area charge laws differ by less than \SI{0.05}{mV}, so the endpoint agreement does not distinguish these mechanisms. Propagating the initial size frequencies gives a narrower endpoint size distribution than measured. With charge parameters determined from the measured size populations, its predicted mean zeta potential is \SI{-9.131}{mV}, with standard deviation \SI{0.994}{mV}. Imposing the measured mean by charge recalibration does not remove the discrepancy in size width. The combined structural and electrokinetic model thus identifies both the size-dependent contribution to zeta potential and the interfacial information needed to interpret it.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Universal Threshold Laws for Dipolar Evaporation of Molecular Fermi Gases
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-10-19 20:00 EDT
Kevin B. Xu, John L. Bohn, Reuben R. W. Wang
Fermi statistics suppress the elastic collisions that rethermalize a Fermi gas during evaporative cooling, creating a fundamental low-temperature bottleneck for producing quantum degenerate gases. We show that, for shielded single-component ultracold dipolar molecular Fermi gases in the Wigner threshold regime, this bottleneck is governed by universal threshold laws fixed by the effective dimensionality of the gas. In this regime, Fermi suppression of rethermalization scales quadratically with temperature in 3D but only linearly in 2D. Consequently, the thermalization-to-loss ratio is more favorable in 2D than in 3D, and these results suggest that 2D geometries are better suited for reaching deep degeneracy. We also present ab initio close-coupling calculations that agree well with experimental measurements on Fermi degenerate gases of KRb molecules, supporting our conclusions.
Quantum Gases (cond-mat.quant-gas), Atomic Physics (physics.atom-ph), Quantum Physics (quant-ph)
9 pages, 4 figures
Physics-Informed Machine Learning for Response Tensors in Crystalline Magnets: Application to Kagome Metals
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-19 20:00 EDT
The prediction of response tensors from magnetic textures is a crucial challenge in the study of noncollinear magnets. Existing methods for constructing descriptors of a given response tensor are limited to first-order multipole expansions or restricted to simple magnetic structures. In this work, we construct a complete symmetry-invariant descriptor basis for arbitrary crystal structures and magnetic textures, providing interpretable features for machine learning modeling of response tensors. We modify the standard principal component analysis framework and derive uncorrelated order parameters that are hierarchically stable: extending the order parameter space to include higher-degree spin order introduces additional order parameters that are uncorrelated to the previous ones. We apply this framework to regression and classification of the anomalous Hall conductivity (AHC) in a magnetic kagome lattice. In particular, in the regime where AHC is well modeled by linear regression of the symmetry-invariant order parameters, we find that the squared regression coefficients, ranked by their magnitude, obey a Zipf-like power law: $ \beta_{r}^2 \propto r^{-\alpha}$ . Our method provides a systematic route to construct interpretable order parameters of all spin orders that connect the symmetry of a magnetic crystal to its response tensors.
Materials Science (cond-mat.mtrl-sci)
Generalized length-gauge time-dependent Liouville equation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-19 20:00 EDT
The length-gauge (LG) time-dependent Liouville equation is a major
workhorse to simulate ultrafast dynamics. The equation features the
commutator between the density operator $ \hat{\rho}$ and the
position operator $ {\bf r}$ , $ \langle n{\bf k}|[{\bf
r},\hat{\rho}]|m{\bf k}’\rangle$ , where $ |n{\bf k}\rangle$ and $ |m{\bf
k}’\rangle$ are Bloch states for bands $ n$ and $ m$ at crystal momenta
$ {\bf k}$ and $ {\bf k}’$ , respectively. This commutator has two
irreconcilable versions: Kohn and Luttinger (Phys. Rev. $ {\bf
108}$ , 590 (1954)) have two partial derivatives with respect to
$ {\bf k}$ and $ {\bf k}’$ , but Aversa and Sipe (AS) (Phys. Rev. B
$ {\bf 52}$ , 14636 (1995)) have one partial derivative and one Dirac
delta. For several decades, this outstanding discrepancy has
received little attention. Here, we show that the generalized LG
time-dependent Liouville equation has two partial derivatives, but
no Dirac delta. Physically, the $ {\bf k}$ -off-diagonal matrix elements
of the position operator provide a channel by which the electric
field generates $ {\bf k}$ -off-diagonal matrix elements for
$ \hat{\rho}$ in LG. The discrepancy emerges when the position
matrix is assumed to be diagonal in $ {\bf k}$ . Consequently the
AS’ equation is a limiting case of our generalized Liouville
equation, where the relative momentum $ {\bf Q}$ between two states is
ignored. Our numerical test reveals that the $ {\bf k}$ -diagonal
formalism yields qualitatively different results and underestimates
both energy absorption and polarization by a factor of 7. Our
study establishes a general formalism for the length-gauge
time-dependent Liouville equation and opens the door for future
research on the ultrafast time scale, while prior results based on
the $ {\bf k}$ -diagonal only equation may need to be revisited.
Materials Science (cond-mat.mtrl-sci)
23 pages, 5 figures, 46 references (submitted)
Coexistence of Griffiths phase and superparamagnetic-like behavior in La-doped antiferromagnetic CaMnO3
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-19 20:00 EDT
Koustav Pal, Shuvendu Ghosh, N. N. S. V. Rama Raju, Chitrada Prasad, Kalipada Das, I. Das
The coexistence of a Griffiths phase and superparamagnetic-like short range interaction in a single-phase homogeneous manganite is of particular interest because it reveals multiple levels of magnetic clustering generated by disorder and competing exchange interactions. In bulk $ \mathrm{La}{0.19}\mathrm{Ca}{0.81}\mathrm{MnO}{3}$ , this unusual magnetic state develops in the antiferromagnetic regime, where A-site disorder strongly modifies the local magnetic landscape. Rietveld analysis confirms a single-phase orthorhombic structure, while magnetic measurements establish a Griffiths phase below $ T{\mathrm{G}} = 280\text{ K}$ through the deviation from Curie-Weiss behavior. Superparamagnetic-like behavior persisting from 280 to 370 K further indicates that isolated magnetic clusters remain stable well into the nominally paramagnetic region. The presence of both phenomena highlights the crucial role of disorder-induced exchange randomness in stabilizing complex magnetic states in correlated perovskite oxides.
Strongly Correlated Electrons (cond-mat.str-el)
8 pages, 3 figures
Materials Science and Engineering: B 335 (2027) 119875
Interplay between high-entropy effects and the superionic transition in fluorite oxides: A liquid-like perspective
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-19 20:00 EDT
Fengnian Zhuang, Gaosheng Yan, Hong Chen, Yi Zhang, Wenshan Yu, Minglong Xu, Shengping Shen
Minor actinide (MA)-bearing mixed oxide (MOX), a prominent high-entropy ceramic (HEC), is a promising candidate for advanced fast reactor fuels. Using a hybrid Monte Carlo/Molecular Dynamics (MC/MD) approach, we reveal that Np and Am segregation establishes a distinct short-range order (SRO) that induces severe lattice distortion. We uncover a competitive mechanism between localized high-entropy blocking effects and collective superionic dynamics, where the anionic kinetic and structural evolution within the 2000-2800 K range is partitioned and governed by the Tammann crossover temperature and superionic transition temperature. In the low-temperature regime, severe lattice distortions induced by the SRO structures create localized electrostatic and strain-coupled potential wells, which spatially confine the O-ions and lead to their sluggish diffusion. The system exhibits increased dynamical heterogeneity as thermal activation alleviates these structural constraints. Crucially, these localized traps spontaneously transform into a highly interconnected, string-like polyhedral topological network. Driven by the maximization of configurational entropy, this structural change creates low-viscosity transport pathways that trigger confinement-enhanced diffusion. Consequently, a dramatic kinetic inversion occurs, where the O-ion mobility of SRO model surpasses that of random solid solution (RSS) model via an entropy-driven compensation mechanism. Finally, through Gibbs free energy minimization and defect analysis, structural and thermodynamic origins of the superionic transition in HEC are elucidated. This study unveils how local chemical ordering regulates ion transport under extreme conditions, providing theoretical support for the design of high-performance nuclear fuels with both superior radiation tolerance and optimized mass transfer capabilities.
Materials Science (cond-mat.mtrl-sci)
48 pages, 13 figures
Pressure-Dependent hcp-to-fcc Phase Transition Path Derived from Exact Lattice Summations over Inverse Power Law Potentials
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-19 20:00 EDT
Tage W. Maltby, Andres Robles-Navarro, Jonathan K. Hartlaub, Andreas A. Buchheit, Øivind Wilhelmsen, Morten Hammer, Peter Schwerdtfeger
We investigate the phase transition between hexagonal close-packed (hcp) and face-centered cubic (fcc) structures along the Burgers-Bain transformation path at pressures up to several hundred gigapascals. We consider a hierarchy of interatomic potentials, from $ (n,m)$ -Lennard-Jones potentials to extended Lennard-Jones two-body interactions in terms of inverse-power expansions and the Axilrod-Teller-Muto three-body term, alongside density functional theory (DFT) calculations for solid argon. For inverse-power potentials, free energies are evaluated through exact lattice sums and efficient integral representations based on generalizations of the Epstein zeta function to anisotropic interaction kernels, followed by lattice-parameter optimization. This methodology enables an accurate determination of the pressure-dependent Burgers-Bain minimum-energy path and the associated activation barrier for the phase transition. The transformation exhibits pronounced symmetry breaking connecting the Burgers and Bain paths, a feature confirmed by DFT calculations. At high pressure, the hcp-to-fcc activation barrier increases approximately linearly with pressure, owing to the dominant pressure-volume contribution. Including entropy and anharmonic effects yields excellent agreement with experimental temperature-dependent volumes up to the melting point. DFT results also highlight the increasing importance of many-body interactions under compression. Whereas two-body potentials predict that the path passes through the body-centered cubic (bcc) structure only at very high pressures, DFT generally predicts a pathway that bypasses bcc. The Axilrod-Teller-Muto term slightly reduces this discrepancy. Furthermore, DFT performs better at high pressures, where dispersion forces become less important.
Statistical Mechanics (cond-mat.stat-mech)
Chirality-resolved imaging of spin waves with a quantum spin
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-19 20:00 EDT
Enbo Zhang, Tiancheng Zheng, Bo-Yuan Yang, Shreyes Nallan, Chengchao Xu, Mark Ku, Jian-Gang Zhu
Spin waves carry their propagation direction in the handedness of their circularly polarized stray field, a property inaccessible to scalar magnetometers. In the Damon-Eshbach surface wave of an in-plane magnetized film, the dipolar field above the film rotates with a handedness fixed by the direction of travel. The nitrogen-vacancy (NV) centre in diamond is an intrinsic polarization analyser: a right-handed field about the NV axis drives one spin transition, and a left-handed field drives the other, in both the ground and the excited state. Here, we exploit the two excited-state transitions, which lie inside the spin-wave band of yttrium iron garnet (YIG), as a pair of chirality channels and image Damon-Eshbach waves in both directions. Because reflection from an etched boundary reverses the handedness, the incident and reflected waves appear as two lines in one spectrum and are imaged separately. In the ground state, the same rule applies, and the selected field drives Rabi oscillations, a route to chirality-selective control of the NV spin by magnons. Reading the two channels gives the direction of a spin wave at one point, without a phase reference. This advances chirality-resolved quantum sensing and provides insight into chiral spin-wave dynamics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph), Quantum Physics (quant-ph)
Adaptive Crack-Tip Localization of Phase-Field Fracture Computations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-19 20:00 EDT
Phase-field models of fracture provide a unified framework for simulating crack nucleation and propagation, but their computational cost remains high because the governing equilibrium and phase-field equations are typically iteratively solved over the entire domain at every staggered iteration. We present an extension of the recently developed adaptive mesh refinement and coarsening framework that localizes not only spatial resolution but also repeated solution effort to a small active patch around the crack tip for linear elastic brittle materials. The inactive exterior is eliminated through a Schur complement and condensed onto the patch interface, and its factorization is reused as long as the patch remains fixed. The phase field is frozen in the exterior, introducing only a small approximation in the crack wake. The method is implemented in FEniCSx and evaluated for quasi-static crack propagation, dynamic crack branching, three-dimensional mixed-mode crack growth, and coalescence of multiple cracks in a unit cell. Across these problems, the condensed formulation reproduces the reference solutions with differences in global quantities below 0.5%, while substantially reducing the number of active degrees of freedom. In the quasi-static surfing problem, wall time speedups increase from 6.9 to 22.8 as the domain size is doubled, demonstrating increasing computational advantage for large-scale phase-field fracture simulations.
Materials Science (cond-mat.mtrl-sci)
Coherent phonons in photoexcited semiconductors from first principles
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-19 20:00 EDT
Yuhui Qiu, Rong-Tian Pang, Meng-Xue Guan, Jin-Jian Zhou
Coherent phonons are phase-locked lattice vibrations that provide a sensitive probe of nonequilibrium dynamics in materials. Existing first-principles equation-of-motion (EOM) approaches have successfully described coherent phonons in metals and semimetals, but their extension to semiconductors requires treating the long-lived electron–hole plasma created by above-gap excitation. Here we extend the first-principles EOM framework to photoexcited semiconductors by incorporating the residual plasma force that shifts the lattice equilibrium together with the plasma-induced renormalization of the electronic structure. For monolayer MoTe$ 2$ , the calculated carrier-density-dependent Te displacement agrees with constrained density-functional perturbation theory only when the renormalized band structure is included. We then show that increasing the photoexcited carrier density enhances both the initial total force and the plasma-shifted equilibrium position of the $ A{1g}$ mode, producing larger coherent lattice oscillations. This density-controlled response appears in both the atomic displacement and the coherent-phonon-induced band renormalization, providing complementary signatures for ultrafast reflectivity and time- and angle-resolved photoemission spectroscopy.
Materials Science (cond-mat.mtrl-sci)
8 pages, 4 figures; accepted for publication in Physical Review B
From Surface Reactions to Inhibitor Coverage: A Machine-Learning-Assisted Computational Study of Area-Selective Atomic Layer Deposition
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-19 20:00 EDT
Gijin Kim, Seungwu Han, Youngho Kang
Area-selective atomic layer deposition (AS-ALD) enables selective material growth for the fabrication of nanoscale semiconductor devices. Predicting inhibitor coverage is essential for understanding and optimizing surface blocking in AS-ALD. Here, we present a computational workflow combining a pretrained universal machine-learning interatomic potential with off-lattice grand canonical Monte Carlo simulations and apply it to inhibitor adsorption and precursor blocking on amorphous SiO2. Realistic surface models reveal substantial site-dependent variations in reaction energies and activation barriers, with silanol groups serving as the primary adsorption sites for aminosilane and related inhibitors and metal precursors. Coverage simulations show that inhibitors producing identical adsorbed fragments can yield different coverages because the intact molecules impose distinct steric constraints, leading to different accessible site densities and blocking capabilities. Beyond coverage, we highlight the importance of the reactivity of adsorbed inhibitor fragments toward precursors in determining inhibitor stability and blocking performance. Together, these findings demonstrate the need to consider both steric effects and chemical reactivity on realistic amorphous surfaces. Our calculations connect local reaction chemistry with inhibitor coverage and provide a computational basis for understanding inhibition mechanisms and selecting suitable inhibitor-precursor combinations for AS-ALD.
Materials Science (cond-mat.mtrl-sci)
15 pages, 9 figures, 1 table. Supplementary information included as ancillary file (+7 pages)
Fully Gapped Superconductivity in the Nonsymmorphic Centrosymmetric Superconductor In2Bi
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-19 20:00 EDT
Atul Gangwar, Kunal Yadav, Barnabha bandyopadhyay, S.Patnaik, K.G.Suresh, Sandip Chatterjee
The nature of superconductivity in nonsymmorphic In2Bi remains an open question, with ongoing debate over whether it exhibits conventional (BCS-like) or unconventional superconductivity. Here we report the physical characteristics and superconducting properties of polycrystalline In2Bi. Measurements of electrical resistivity, magnetization, penetration depth, and specific heat demonstrate the superconducting transition temperature about 6 K, with a sharp transition in resistivity (Delta_Tc = 0.1 K) and RRR = 57.32, reflecting the high quality of the sample. The upper critical field Hc2(0) obtained from resistivity and magnetization measurements are in good agreement with each other and are smaller than the Pauli limit, suggesting orbital limited mechanism. The coherence length = 35.43 nm, penetration depth = 101.9 nm and electron-phonon coupling constant = 1.05 suggest strongly coupled type-II superconductivity. For T<Tc, Delta_lambda(T) is best described by an s-wave BCS model and does not have any power law dependency with T, which is expected for a nodeless superconducting order parameter. The superfluid density reveals a fully gapped superconductivity with a gap of 2Delta_0/kBTc = 4.02. In the superconducting state, the electronic specific heat is best described by an s-wave BCS model with a gap of 2Delta_0/kBTc = 4.05. All these results from the present study indicate that In2Bi is a typical type-II,BCS-like, strongly coupled, and fully gapped superconductor in the dirty limit.
Superconductivity (cond-mat.supr-con)
11 pages, 7 figures
Hidden Staggered Superconducting Order in V2Se2O-Family Altermagnets
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-19 20:00 EDT
Chun Yu Wan, Xiangxi Zhang, Fei Yang, Junwei Liu
$ \eta$ pairing describes a staggered superconducting condensate whose order parameter changes sign between neighboring unit cells while maintaining a uniform magnitude. Nearly four decades after its theoretical proposal by C. N. Yang, a material platform for stabilizing $ \eta$ pairing has remained elusive. Here, we reveal that altermagnetism, despite being pair breaking for conventional BCS pairing, naturally favors $ \eta$ -like pairing in V$ _2$ Se$ _2$ O-family altermagnets. Their valley-contrasting spin structure gives rise to oppositely spin-polarized, symmetry-related valleys centered at $ X=(\pi,0)$ and $ Y=(0,\pi)$ , which form spin-singlet pairing partners separated by the commensurate momentum $ \mathbf Q=(\pi,\pi)$ , thereby favoring an $ \eta$ -like condensate. Self-consistent calculations demonstrate that the resulting $ \eta$ -like state remains robust over broad variations of chemical potential, hopping parameters, and Fermi-surface topology. To detect this hidden staggered order, we propose a phase-sensitive Josephson measurement with a uniform superconductor, where destructive interference suppresses single-Cooper-pair tunneling while preserving two-Cooper-pair processes. This constitutes a charge-$ 4e$ -like Josephson response despite a bulk condensate composed of charge-$ 2e$ Cooper pairs, providing a direct phase-sensitive signature of the otherwise elusive $ \eta$ -like condensate in V$ _2$ Se$ _2$ O-family altermagnets.
Superconductivity (cond-mat.supr-con)
Kitaev, semi-Dirac, and spinon quantum spin Hall liquids on the square-hexagon-dodecagon lattice: A parent projective symmetry group classification
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-19 20:00 EDT
The square-hexagon-dodecagon (SHD) lattice hosts an exactly solvable Kitaev spin liquid, while further-neighbor couplings frustrate its Heisenberg magnet into classically degenerate lines where quantum fluctuations can melt the Néel order. To place this state among the lattice’s spin liquids, we classify fermionic parton mean-field states with singlet and spin-orbit-coupled triplet amplitudes by their projective symmetry groups (PSGs). As SHD sites lack site symmetry, its $ Z_2$ PSGs are the projective classes of $ p6mm$ with time reversal, from which those of every single-orbit $ p6mm$ lattice follow. In the idealized Kitaev model, where lattice operations do not rotate spins, these liquids carry a single $ Z_2$ PSG descending from the $ SU(2)$ Lieb-flux state, and their projections are exact eigenstates. The PSG’s sixfold-rotation sign, fixed by the dodecagon flux, doubles all Majorana bands, and the mirrors exclude a chiral phase in any uniform field, so only a sublattice-staggered three-spin term drives the non-Abelian Ising phase. Beyond the Kitaev state, we find a critical semi-Dirac spin liquid, with mean-field correlations $ \propto r^{-3}$ along three directions and $ r^{-6}$ otherwise, and extended Dirac phases with up to $ 48$ fermion flavors, among them an $ N_f=12$ state whose PSG forbids every singlet mass. Out-of-plane Dzyaloshinskii-Moriya couplings gap the Dirac states of its $ U(1)$ class into a mean-field spinon counterpart of the Kane-Mele quantum spin Hall insulator, with spin Chern number $ 1$ or $ 3$ and spin-carrying monopoles. Chiral states imply Kalmeyer-Laughlin, semion$ \times$ semion, and three-fermion orders, rotation-breaking ones show $ q\to -q$ asymmetric neutron spectra, and sign-alternating fluxes break time reversal alone. Masses and monopoles in these many-flavor phases and the energetics of frustrated SHD Heisenberg models are natural next steps.
Strongly Correlated Electrons (cond-mat.str-el)
Main paper (55 pages, 18 figures, 16 tables) and Supplemental Material
Parity-dependent sublattice structure of local $2\times2$ correlations in domino tilings of the Aztec diamond
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-19 20:00 EDT
Chaeyeon Kim, Suhwan Yoo, Jeehoon Choi, Hee Young Kwon, Changyeon Won
We study local $ 2\times2$ correlations in uniformly random domino tilings of the Aztec diamond $ \mathrm{AZ}(n)$ , a dimer model with frozen corners and a liquid region bounded by the Arctic circle, and compare them with the square chessboard. For every elementary square the probabilities $ P_H$ and $ P_V$ of the two coverings by a pair of parallel dominoes satisfy $ P_H=P_V=P_1P_2+P_3P_4$ , where $ P_1,\dots,P_4$ are the probabilities of the four surrounding edges. This known identity, a case of Kuo’s graphical condensation, reduces the spatial profile of $ P_H$ to single-edge probabilities, which we compute exactly from the inverse Kasteleyn matrix for all squares of $ \mathrm{AZ}(n)$ . The squares form two interleaved sublattices, distinguished by the color of their lower-left cell. The parity of $ n$ decides which sublattice dominates near the center: the one containing the central square for odd $ n$ , and the other one for even $ n$ . This sign rule holds for the averaged sublattice contrast for all $ 4\le n\le22$ . It also fixes the location of the global maximum of $ P_H$ , which lies at or next to the center for odd $ n$ and several lattice spacings away for even $ n$ . Within the central sublattice, the preferred square follows a mod-4 pattern that matches the exactly pinned mean height of the center. On the $ L\times L$ chessboard the same rule holds with $ n$ replaced by the half-width $ L/2$ , but the contrast is two to six times weaker, the central edge probability never equals $ 1/4$ , and the maxima of $ P_H$ are pinned to the corners. The exact $ 1/4$ values and the interior, parity-selected maxima are therefore features of the Aztec geometry.
Statistical Mechanics (cond-mat.stat-mech), Mathematical Physics (math-ph)
Transport Signatures of a Kinetically Self-Trapped Nagaoka Polaron
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-19 20:00 EDT
Nagaoka polarons are canonical examples of kinetic magnetism. Although their spin structure is well understood, their transport remains unexplored. We compute the dynamical mobility of a single hole in the square-lattice $ t$ -model using resummation-based quantum Monte Carlo and analytic continuation. Upon cooling, an incoherent Drude-like response gives way to a finite-frequency peak as the dc mobility vanishes. The peak signals an internal mode of a hole confined by its ferromagnetic cloud. Our results establish transport as an incisive probe of polaron formation and kinetic self-trapping.
Strongly Correlated Electrons (cond-mat.str-el)
15 pages, 9 figures, including Supplemental Material (9 pages, 5 figures)
Crystal Field-Phonon Coupling in ErFeO$_3$ Single Crystal Via Inelastic Neutron Scattering
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-19 20:00 EDT
Guochu Deng, Xiaoxuan Ma, Wanting Yang, Wei Ren, Shixun Cao, Zhenxiang Cheng, Garry J. McIntyre
Crystal-field (CF) excitations and their coupling to lattice vibrations were investigated in ErFeO$ _3$ using inelastic neutron scattering. Pronounced modifications of the excitation spectra, including energy shifts, intensity redistribution, and linewidth changes, were observed as a consequence of CF-phonon coupling. Significant renormalization of the first and second CF excitations, located near 5 meV and 12 meV, respectively, was detected along both transverse and longitudinal directions in the vicinity of the reciprocal-space point Q = (2, 0, 4). The coupling effects become more prominent as the temperature increases from 300 K to 650 K, while a slight suppression is observed at 750 K. Remarkably, CF excitation peaks that are strongly weakened by thermal population effects re-emerge in specific momentum regions through interaction with phonon modes. The coupled excitations exhibit characteristic signatures of hybridization, including energy renormalization, intensity enhancement, and linewidth narrowing. Density-functional-theory-based phonon calculations further support the interpretation of CF-phonon coupling in ErFeO3. These results demonstrate that strong interactions between CF excitations and lattice vibrations can substantially modify the excitation spectra in rare-earth orthoferrites.
Strongly Correlated Electrons (cond-mat.str-el), Other Condensed Matter (cond-mat.other)
14 pages, 5 figures
Diffusion-controlled reactions with time-dependent surface reactivity
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-19 20:00 EDT
We investigate diffusion-controlled reactions on a reactive surface with time-dependent reactivity. Starting from a conventional formulation via diffusion equation with Robin boundary condition for the macroscopic concentration of particles, we aim at quantifying how temporal variations of reactivity affect the survival probability and the associated first-reaction time (FRT) of a single particle on the reactive surface. Using an adiabatic description, we first identify five long-time regimes of the first-reaction time distribution, ranging from exponential and stretched-exponential to power-law decay. In particular, sufficiently rapid decay of the reactivity leads to a nonzero probability of never reacting, despite diffusion in a bounded domain. Second, we provide a probabilistic reformulation of this problem and compare it with a different scenario of encounter-dependent reactivity. Our theoretical predictions are validated via extensive Monte Carlo simulations.
Statistical Mechanics (cond-mat.stat-mech), Chemical Physics (physics.chem-ph)
Nonergodicity from Hilbert-Subspace Cloning
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-19 20:00 EDT
We identify a class of nonintegrable quantum many-body systems composed of single Pauli strings that possess an extensive number of noncommuting local conserved quantities and exhibit partial ergodicity breaking due to exponentially degenerate energy spectra. We show that such systems exhibit a novel mechanism, Hilbert-subspace cloning, where the identical chaotic Hamiltonian acts on each of exponentially many disconnected Hilbert subspaces. Although the dynamics within each clone thermalizes, quantum coherence between clones remains protected and detectable by local observables. Consequently, the long-time behavior of local observables is described by a coherence-preserving partial Gibbs ensemble, where the hidden subsystem retains its initial quantum coherence.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
6 pages, 3 figures, and End Matter
From quantum emitters to technological platforms: a perspective on semiconductor quantum dots
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-19 20:00 EDT
Klaus D. Jöns, Dorian A. Gangloff, Doris E. Reiter
Photonic quantum technologies are based on controlled photon states. To generate these, quantum dots have emerged as excellent sources of single and entangled photons. In this Perspective, we briefly review the chronological development of quantum dots as photon sources, from their beginnings as quantum emitters in the early 2000s to the advanced photonic devices being developed today. We highlight the interplay between fundamental research and industrial aspects before discussing the photonic quantum technologies we expect to emerge in the near future.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
Field-induced incommensurate–commensurate transitions in anisotropic magnets
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-19 20:00 EDT
P.T. Bolokhova, A.V. Syromyatnikov
We study field-induced incommensurate–commensurate transitions (ICTs) in classical spin chains with Dzyaloshinskii-Moriya interaction (DMI) $ D$ , strong easy-plane anisotropy, and weak easy-axis anisotropy $ A$ within the easy plane. This model describes systems with ferromagnetic layers coupled by exchange interaction with DMI. The magnetic field $ \bf H$ is applied in the easy plane at an arbitrary angle $ \delta$ to the easy axis stabilizing a soliton lattice in the ground state. We consider ferromagnetic and antiferromagnetic in-chain exchange interactions within the continuum limit and show that the easy-axis anisotropy leads to qualitatively different effects in these two cases: the ferromagnetic chain is described by a double-sine-Gordon-type equation with phase-shifted harmonics, whereas the antiferromagnetic chain reduces to a sine-Gordon equation. For the latter case, phase boundaries between incommensurate and commensurate states are found analytically in $ (H,A,D,\delta)$ space and confirmed by numerical calculations for certain $ D$ and $ \delta$ values. Close to all ICTs, results of the continuum consideration become invalid due to a stochastic destruction of near-separatrix solutions which either make an ICT a first-order transition or stabilize states with spatially irregular soliton and antisoliton arrangements.
Strongly Correlated Electrons (cond-mat.str-el)
8 pages, 3 figures
Light-induced local control of magnetic anisotropy and domain pattern in Co/Pt multilayers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-19 20:00 EDT
Ivan Soldatov, Aman Singh, Volker Neu, Rudolf Schäfer, Andrei Sherstobitov, Yana Vaynzof, Stanislav Bodnar
Control of magnetic anisotropy is essential for the fabrication of next-generation devices in spintronics and magnetic memory. While conventional approaches such as material composition, thermal annealing, and ion bombardment are widely used, achieving spatially resolved, continuous control remains a challenge. Herein, we demonstrate a dual-regime, localized control over both transient magnetic states and permanent intrinsic properties in perpendicularly magnetized Co/Pt multilayers using ultra-short laser pulses. By employing a multi-scale approach combining Kerr microscopy, magnetic force microscopy, and vibrating sample magnetometry, we reveal that low-fluence irradiation enables a reversible, helicity-dependent accumulation of magnetic phases without altering the intrinsic quasistatic properties. Conversely, high-fluence exposure acts as localized thermal annealing that permanently hardens the magnetic system. This structural relaxation leads to a substantial enhancement of the effective perpendicular magnetic anisotropy, driving a twofold increase in the local coercive field and expanding the equilibrium stripe domain width. By offering both reversible spin manipulation and deterministic engineering of 2D magnetic landscapes, this work paves the way towards flexible, lithography-free anisotropy structuring for advanced spintronic applications.
Materials Science (cond-mat.mtrl-sci)
Confinement-induced toughening in delignified wood-polyacrylamide composite hydrogels
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-19 20:00 EDT
Kohei Shimogata, Tetsuo Yamaguchi
With growing interest in environmental conservation, polymer composites incorporating wood-derived materials have attracted significant attention. While research has focused extensively on hard composites utilizing delignified wood or cellulose nanofibers (CNF) and soft composites reinforced with CNF, there have been a limited number of studies on the development of soft composites that utilize the porous cellular structure of wood, with few exceptions. In this study, we fabricated soft composites by infiltrating delignified wood with polyacrylamide hydrogel and subjected them to uniaxial compression tests. The results demonstrated that these materials exhibited far superior strength and toughness compared to either delignified wood or polyacrylamide hydrogel alone. Through systematic investigation and theoretical analysis, we identified the mechanisms underlying these enhancements in strength and toughness. Specifically, in addition to the sacrificial bond breakage known to enhance toughness in double-network hydrogels, we propose that mechanical confinement, arising from the soft, incompressible hydrogel filling the hollow cell lumens, generates excess stress and acts to resist compressive deformation. This approach, which utilizes the cellular structure as a filler, suggests the potential for creating a new class of high-toughness composite materials.
Soft Condensed Matter (cond-mat.soft)
Universal Long-distance Tail of Particle-number Density near a Wall in Superfluids
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-10-19 20:00 EDT
We investigate the long-distance recovery of the particle-number density near a static, impermeable wall in a $ d$ -dimensional Galilean-invariant superfluid. Using superfluid effective field theory (EFT) on a half-space, we show that quantum phonon fluctuations produce a $ z^{-(d+1)}$ tail in the smooth density profile at zero temperature, where $ z$ is the distance from the wall. The tail coefficient is fixed by the bulk equation of state and is independent of microscopic wall details. At low temperature $ T$ , the thermal length $ c_s/T$ , with $ c_s$ the bulk sound speed, separates the zero-temperature behavior at intermediate distances from a thermal $ Tz^{-d}$ tail at larger distances for $ d>1$ . For $ d=1$ , the long-distance phonon contribution instead decays as $ \exp(-4\pi Tz/c_s)$ . The EFT applies to both Bose and Fermi superfluids, including strongly interacting Fermi gases at unitarity. We estimate the normalized tail amplitude in three dimensions across the BCS–BEC crossover using experimental sound-speed data.
Quantum Gases (cond-mat.quant-gas), High Energy Physics - Theory (hep-th)
6 pages, 2 figures, plus 8 pages of Supplemental Material
Non-Adiabatic Spin-Induced Currents in Magnetic Weyl Semimetals
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-19 20:00 EDT
Kota Watanabe, Akihiro Ozawa, Hiroaki Ishizuka, Hiroki Isobe, Kentaro Nomura
We theoretically study dc electric currents induced by rapid spin precession in noncentrosymmetric magnetic Weyl semimetals using the Floquet–Keldysh Green’s-function formalism. The spin dynamics act as a time-dependent chiral gauge field and the geometric structure of electric currents is expressed in terms of the Berry curvature, the quantum metric, and the shift vector. For an isotropic Weyl cone, only an injection current is generated. This current scales quadratically with the driving frequency and linearly with the relaxation time associated with coupling to a fermionic bath. We further show that a finite Weyl-cone tilt modifies the available interband-transition phase space, smooths the frequency dependence of the current, and allows for a shift current and another type of injection current, both of which flow in directions determined by the tilt and the direction of the precession. A finite net current can remain after summing contributions from Weyl nodes of opposite chiralities when their transition phase spaces are inequivalent.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
20 pages, 6 figures
Fractionalized Fermi Liquid and d-wave Superconductivity in Ba2CuO3+x
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-19 20:00 EDT
M. S. Laad, S. Koley, A. Taraphder
Strongly enhanced superconductivity (SC) (Tc = 73 K) in Ba2CuO3+x (BCO) challenges the longheld paradigm of the irrelevance of the dz2-like states in cuprates. Using tight-binding band structure plus dynamical mean-field theory (TB+DMFT), we find that a fractionalized Fermi liquid (FFL) is the normal state for the parameters realistic for BCO. Transport properties exhibit strange metal behavior above Tcoh~38 K, supporting a direct instability of this strange metal to SC. Irrelevance of one-fermion inter-band mixing, itself a non-trivial consequence of the FFL state, preferentially enhances two-fermion hopping processes and provides a novel route for both SC and competing excitonic order(s) arising directly from the FFL. The proposed scenario also clarifies the role of dz2 band in shaping the physical responses of BCO.
Strongly Correlated Electrons (cond-mat.str-el)
Emergence of Correlations Between Records and Maximum in Random Time Series
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-19 20:00 EDT
Satya N. Majumdar, Sanjib Sabhapandit, Gregory Schehr
We compute exactly the covariance between the maximum $ M$ and the number of records $ K$ in a discrete time series of $ n$ entries as a quantitative probe of the history leading to an extreme event. For continuous IID series, with a common probability distribution function (PDF) $ p(x)$ , we find the striking result that $ M$ and $ K$ are uncorrelated for any $ n \geq 1$ . We show that this independence is rather fragile and the covariance $ C_q(n)$ between $ M$ and $ K$ becomes nonzero when $ p(x)$ becomes discontinuous due to a delta-component at $ x=0$ with an amplitude $ 0< q < 1$ . This time series models the occurrence of dry days with probability $ q$ in a precipitation time series when there is no rainfall. We show that there is an interesting shape transition at a critical value $ q_c$ where the covariance $ C_q(n)$ , as a function of $ n$ , changes from monotonic ($ q<q_c$ ) to non monotonic behavior (for $ q>q_c$ ). We compute the critical strength $ q_c$ exactly. Furthermore, for large $ n$ , we show that $ C_q(n)$ decays as a power law, with an exponent that depends on the tail of $ p(x)$ . We then compare our theoretical predictions with real precipitation data from several weather stations across Germany, finding a very good agreement.
Statistical Mechanics (cond-mat.stat-mech), Probability (math.PR), Data Analysis, Statistics and Probability (physics.data-an)
Letter: 5+2 pages and 6 figures; Supp. Mat.: 15 pages and 5 figures
Inducing Extraordinary-log Criticality through a Quantum Spin Chain
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-19 20:00 EDT
Grigorios Makris, Francesco Parisen Toldin, Stefan Wessel
We demonstrate the emergence of extraordinary-log criticality in a quantum many-body system by coupling a spin-$ 1/2$ Heisenberg chain to a two-dimensional quantum critical Heisenberg bilayer. Under the quantum-to-classical mapping, the chain acts as a plane defect in a three-dimensional critical environment for which the extraordinary-log universality class has recently been predicted. Using large-scale sign-problem-free quantum Monte Carlo simulations, we directly probe the renormalization-group flow of the effective defect coupling through the spin stiffness. We observe the characteristic logarithmic growth with linear system size $ L$ , corresponding to a stable weak-coupling fixed point and a running coupling $ g(L)\sim 1/\log L$ . Furthermore, the extracted step-scaling function quantitatively follows the universal renormalization-group flow predicted for the extraordinary-log universality class, including the leading and subleading universal coefficients. Our results establish extraordinary-log criticality in a genuine quantum many-body setting and show that its universal behavior persists despite the topological $ \theta$ -term present in the low-energy field theory of the isolated spin chain.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech)
8 pages, 11 figures
Simulation of centrifugal separation of particles with equal sedimentation velocities
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-19 20:00 EDT
Yurika Miyake, Natsuki Asami, Ken-ichi Amano
Conventional centrifugal sedimentation cannot readily separate particles with the same sedimentation velocities. Density gradient centrifugation, although highly selective, exposes delicate particles such as drug delivery system (DDS) nanoparticles and exosomes to high osmotic pressure that can cause shrinkage, rupture, or expansion. To separate particles with equal or similar sedimentation velocities while preserving their properties, we propose two methods that exploit thermal fluctuations (Brownian motion): the centrifugal Brownian ratchet method, which uses asymmetric structures, and the centrifugal wavy-channel method, which uses geometric barriers. Two-dimensional Brownian dynamics simulations combining Stokes-Einstein diffusion with centrifugal sedimentation were performed, and particle transport was analyzed using the Péclet number. In the ratchet method, particles with identical sedimentation velocities but different Péclet numbers showed statistically distinct mean arrival positions and times. In the wavy-channel method, periodic entropic barriers interacting with differences in transport properties produced arrival-time differences, achieving temporal separation even for particles with identical sedimentation velocities or Péclet numbers. Both methods separate particles without relying on sedimentation-velocity differences and are expected to preserve particle properties. Because they neither depend on electrical properties nor require a change of medium, they may also be applicable to particles in liquid metals, oils, organic solvents, and ionic liquids.
Soft Condensed Matter (cond-mat.soft), Computational Physics (physics.comp-ph)
Equal-spin pairing at finite Cooper-pair momentum in $p$-wave magnets
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-19 20:00 EDT
The realization of Fulde-Ferrell (FF) superconducting states has long been pursued but remains challenging because of the large Zeeman splitting required. Here, we demonstrate that $ p$ -wave magnets can host equal-spin finite-pair-momentum states with $ p$ -wave symmetry, termed FF states, at arbitrarily weak fields. Our Bogoliubov-de Gennes analysis shows that, owing to the displacement of the Fermi surface, two equal-spin electrons in the FF states pair at the same energy, just as in the opposite-spin zero-pair-momentum states of the same gap symmetry. At zero field, the FF states are therefore exactly degenerate with these zero-pair-momentum counterparts. An arbitrarily weak Zeeman field lifts this degeneracy and makes the FF states the superconducting ground state, since they remain stable owing to their equal-spin nature, whereas their counterparts are suppressed by the formation of Bogoliubov Fermi surfaces. These findings identify the fermiology of $ p$ -wave magnets as a promising route toward long-sought finite-momentum superconductivity.
Strongly Correlated Electrons (cond-mat.str-el)
14 pages, 6 figures, 1 table
When Cooling Meets Flow: Advection-Driven Orientation Selection in Phase Separation around a Moving Cooling Source
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-19 20:00 EDT
We investigate phase separation in a binary fluid subjected to a moving Gaussian cooling source and externally imposed material flow. Unlike conventional homogeneous quenches, the moving thermal field initiates phase separation at different times across the system, creating a spatially varying thermal history and local age. The interplay of a moving cooling source, phase separation and external flow field introduces directional bias, resulting in anisotropic pattern formation. Using an advective Cahn-Hilliard-Cook model coupled to a spatially and temporally varying temperature field, we examine how front propagation, thermal diffusion, phase separation, and material transport jointly select the evolving morphology. In the absence of flow, increasing the cooling-source velocity drives a transition from nearly symmetric structures to asymmetric spiral-like patterns and, at higher velocities, to narrow elongated domains as the thermal front increasingly lags behind the source. Advection reorganizes the phase-separated domains by transporting, stretching, and reorienting them. At low flow velocities, competing thermal and advective histories produce distinct regions of flow-aligned and vertical layers. A stronger flow aligns the domains predominantly along the flow direction. Our results demonstrate that a moving thermal history can encode a spatial record of non-equilibrium phase separation. This work provides a route to controlled morphology selection through the competition between front propagation, thermal diffusion, and material flow.
Soft Condensed Matter (cond-mat.soft), Fluid Dynamics (physics.flu-dyn)
13 pages, 16 figures
The effect of oxygen on the surface tension of AlTi metallic alloys
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-19 20:00 EDT
Yuna Kato, Jürgen Brillo, Thomas Voigtmann, Linnea Heitmeier
We perform molecular dynamics (MD) simulations of AlTi metallic alloy melts, with a specific focus on surface properties and the effect of oxygen. The simulations use a machine-learned inter- action potential (MLIP) that has recently been tested through experimental data for the statical and dynamical properties of AlTi melts in the bulk [Kato et al. (2026)]. We find that the surface- tension response to oxygen depends strongly on the AlTi composition. Element-resolved density profiles show that oxygen enrichment near the interface is accompanied by a suppression of the Al surface segregation observed in the oxygen-free liquid. The results are compared to experimental values obtained using levitation techniques in microgravity.
Materials Science (cond-mat.mtrl-sci)
9 pages, 8 figures
Topological edge and domain-wall phonons in the mass-dimerized diatomic chain: complex band structure, Zak phase, and spectral unfolding
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-19 20:00 EDT
The one-dimensional chain with alternating masses is the simplest mechanical system with a topological band structure. We give a fully analytical account of its localized vibrations built on the complex band structure. The evanescent Bloch waves available at each frequency are matched directly to force balance at a free end or a domain wall, without transfer matrices, which yields closed-form frequencies and decay lengths for every localized mode. The free-end mode sits at a branch point of the complex band structure, where the acoustic and optical sheets join and the decay is fastest. For uniform springs, a sharp wall between the two mass orderings hosts one in-gap mode, symmetric at the light$ \mid$ light wall and antisymmetric at the heavy$ \mid$ heavy wall, and an adiabatic construction shows that these are the same topological mode; the light$ \mid$ light wall also binds a non-topological mode above the optical branch. Spectral unfolding makes this classification visible in momentum space: the sign of the Bloch factor sets the zone-center or zone-boundary character of each mode, and its magnitude sets the width. The Zak phase, quantized by inversion, identifies the modes of topological origin and fixes a half-integer mode count per band at a wall, while the chiral symmetry known to be hidden in strain coordinates explains which frequencies are pinned.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
7 figures
Fundamental Bounds on the Oscillation Efficiency of Markov Networks
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-19 20:00 EDT
Stochastic oscillations are commonly identified through peaks in their power spectra, yet the fundamental limits on their strength and energetic cost remain unclear. Here we establish universal dynamical and thermodynamic bounds on oscillation efficiency in Markov networks, showing how finite state spaces constrain spectral peak enhancement. In particular, we demonstrate that networks maximizing modal coherence need not maximize oscillation efficiency. We further derive dissipation bounds that connect oscillation efficiency to the relaxation speed and stationary probabilities, revealing an unavoidable energetic cost of maintaining pronounced oscillations at a specified relaxation timescale. These bounds remain strictly positive in regimes where existing explicit spectral dissipation estimates vanish, with stronger constraints for normal networks and uniform rings. Our results distinguish spectral oscillatory strength from modal coherence and reveal how network dynamics and thermodynamic dissipation jointly limit stochastic oscillations.
Statistical Mechanics (cond-mat.stat-mech), Molecular Networks (q-bio.MN)
Interfacial Faraday instability driven by interspecies-interaction modulation in a phase-separated binary Bose-Einstein condensate
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-10-19 20:00 EDT
We investigate interfacial Faraday instabilities in a quasi-two-dimensional, phase-separated binary Bose-Einstein condensate driven by periodic modulation of the interspecies scattering length. In the strongly immiscible regime, the interspecies interaction energy is concentrated near the internal interface, linking the modulation to interfacial tension and the capillary restoring force. We quantify the first-order tension response through its logarithmic sensitivity and account for nonlinear tension variations at finite modulation amplitudes. A sharp-interface capillary model and Floquet analysis yield discrete azimuthal-mode frequencies and primary instability tongues that shift toward higher driving frequencies with increasing mode order. Gross-Pitaevskii simulations reveal star-shaped interface patterns with threefold to eightfold rotational symmetry. The eightfold mode exhibits subharmonic oscillations and approximately exponential growth of its period-averaged amplitude over a small-deformation interval. These results provide a route to frequency-selective excitation of interfacial capillary modes through interspecies-interaction control.
Quantum Gases (cond-mat.quant-gas)
12 pages, 10 figures
Kinematics of Inverse Compton Scattering from Dirac Carriers in Graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-19 20:00 EDT
Dar Faheem Ul Haq, Naveed Ahmad Shah, SSZ Ashraf
We examine the kinematics of Compton and inverse Compton scattering by Dirac carriers in graphene. Unlike photons in vacuum, which propagate at the speed of light c, graphene carriers have a characteristic velocity vF, with vF much less than c. This difference means that the standard Compton scattering formula cannot be applied to graphene simply by replacing c with vF. We first examine Compton-like scattering for a gapless Dirac carrier initially at the Dirac point and for a gapped carrier at the band edge, both corresponding to zero in-plane momentum. We then consider scattering from an energetic gapless Dirac carrier. By combining energy conservation with the graphene dispersion and in-plane momentum conservation, we obtain a quadratic equation for the scattered photon energy within the model considered. This relation is the main kinematic result of the work. We identify inverse Compton-like scattering by the transfer of energy from the carrier to the photon, subject to the simultaneous conservation of energy and in-plane momentum. We also discuss how this process differs kinematically from Doppler-shifted emission, Cerenkov-like radiation, harmonic generation, photon drag, and other nonlinear optical processes. Finally, we propose a time-resolved pump-probe arrangement in which the scattered photon spectrum is the primary observable, while time- and angle-resolved photoemission spectroscopy (TR-ARPES) provides an independent probe of the nonequilibrium carrier distribution. These results provide a kinematic framework for analysing inverse Compton-like scattering in graphene and for identifying the conditions under which energy can be transferred from energetic Dirac carriers to photons.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
16 pages, 2 figures
Statistics-controlled topological phases in a Su-Schrieffer-Heeger ladder
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-10-19 20:00 EDT
Rajashri Parida, Biswajit Paul, Smitha Vishveshwara, Diptiman Sen, Tapan Mishra
In strictly one-dimensional lattices, free fermions and hard-core bosons exhibit equivalent physical properties in many-particle systems. However, this statistical equivalence generally breaks down upon moving to higher dimensions. Our work investigates the significant effects of this difference on the topological phase transition in a minimal system lying away from one dimension: the two-leg Su-Schrieffer-Heeger (SSH) ladder. Starting in the limit of two decoupled SSH chains having opposite hopping dimerization patterns (staggered dimerization), we demonstrate that introducing inter-leg coupling drives a transition from a topological to a trivial phase for both spinless fermions and hard-core bosons. However, the topological to trivial phase transition boundary is strongly sensitive to the underlying particle statistics. We find that this intriguing effect favors a trivial phase sandwiched between the two topological phases with opposite characters for the case of hard-core bosons, resulting in a reentrant topological phase transition. In contrast, this reentrant phenomenon is absent for spinless fermions, with the topological phases being separated by a gapless line instead of an intervening trivial phase. This study demonstrates the interplay between particle statistics and topological features, revealing fundamentally different properties in an experimentally accessible set-up.
Quantum Gases (cond-mat.quant-gas)
5+2 pages, 5 figures
Termination-dependent surface Fermiology in the intercalated altermagnet CoNb$_4$Se$_8$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-19 20:00 EDT
Pietro Maria Forcella, Alessandro De Vita, Matthew D. Watson, Sammar Tayyab, Chiara Bigi, Iulia Cojocariu, Marcin Szpytma, Matteo Jugovac, Andrea Locatelli, Tevfik Onur Mentes, My Bang Petersen, Paolo Moras, Polina M. Sheverdyaeva, Christopher Candelora, Ilija Zeljkovic, Federico Motti, Jill A. Miwa, Vincent Polewczyk, Matthieu Jamet, Matteo Calandra, Younghun Hwang, Davide Romanin, Federico Mazzola
Altermagnets have recently gained attention for hosting symmetry-enforced spin-split bands despite zero net magnetization. Angle-resolved photoelectron spectroscopy (ARPES) offers direct access to their electronic structure. However, the intrinsic surface sensitivity of this technique complicates the identification of the observed features: Surface states can be misinterpreted as the spin-split counterpart of bulk bands. This issue becomes particularly relevant for layered intercalated systems, where micrometer-sized domains with distinct terminations often coexist on a cleaved surface. We discuss this scenario for CoNb$ _4$ Se$ _8$ , one of the first established layered altermagnets. Supported by density functional theory calculations, we employ micro-ARPES to probe individual domains and reveal two contrasting surface terminations. We identify Co- and Se-terminated domains with characteristic surface states arising from bulk-surface connectivity of the material. Our work shows that termination-dependent surface contributions are essential for the reliable spectroscopic identification of altermagnetism and for assessing its presence across the family of layered materials.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Stability and Nonlinear Dynamics of Field-Driven Extended Domain Walls with Interfacial Dzyaloshinskii-Moriya Interaction
New Submission | Other Condensed Matter (cond-mat.other) | 2026-10-19 20:00 EDT
Enzo Fabrizio Pusiol, Alberto Rosso, Alejandro B. Kolton
We analyze the stability and non-linear dynamics of extended domain walls (DWs) with Dzyaloshinskii-Moriya interaction (DMI) driven by an external magnetic field in the clean limit (i.e., in the absence of disorder and thermal fluctuations). We show that for moderate DMI strengths, the dynamics in both the low- and high-field regimes are accurately described by a rigid-wall Walker model that neglects flexural degrees of freedom. At intermediate fields, however, the system undergoes a transition into a non-trivial spatio-temporally chaotic regime characterized by dynamically roughened domain walls displaying single- or multi-valued profiles. The phase boundaries delimiting this regime in the magnetic field-DMI phase space are computed using a linear stability analysis based on Floquet theory applied to the extended domain wall, explicitly accounting for DMI and internal phase dynamics. Our theoretical analysis and predicted phase diagram are fully supported by numerical micromagnetic simulations solving the full Landau-Lifshitz-Gilbert equation.
Other Condensed Matter (cond-mat.other), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Soft Condensed Matter (cond-mat.soft)
14 pages, 13 figures, 2 tables
Hydrogen Ion-Cut Single-Crystal Diamond Membranes for Wide and Ultrawide Bandgap Semiconductor Heterointegration
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-19 20:00 EDT
Xuanyu Zhou, Chenyu Wang, Dmitry Shinyavskiy, Lu Chen, Luke Suter, Andreas Graff, Michel Simon-Najasek, Vincent Gambin, Katherine T. Fountaine, Zhenqiang Ma, Frank Altmann, Matthias Muehle, Jung-Hun Seo
Single-crystal diamond membranes (SCDms) were created using a hydrogen ion-cut process combined with a two-step post-implantation annealing, electrochemical etching, and micro-transfer printing. Monte Carlo simulations comparing H, He, C, and O implantation predicted a narrower vacancy-distribution profile for hydrogen under the implantation conditions examined. Raman spectroscopy was used to evaluate implantation-induced lattice damage and its recovery during annealing and membrane release, while optical bandgap analysis provided further evidence of restoration of the diamond lattice structure. After delamination and removal of residual graphitic material, freestanding SCDms with improved crystalline quality were obtained. The SCDms were subsequently transferred to GaN, SiC, AlGaN, and AlN substrates without an adhesive layer. The successful formation of diamond/WBG and diamond/UWBG heterostructures demonstrates the feasibility of integrating the SCDms with a range of semiconductor platforms. Overall, these results establish hydrogen implantation as an effective route for producing high-quality SCDms for future diamond-based heterogeneous integration applications.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Magnetic Field-assisted Crystallographic Selection During Grain Growth in Non-Magnetic Polycrystals: A Phase-Field Study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-19 20:00 EDT
Rakesh Maurya, Soumya Bandyopadhyay, Somnath Bhowmick, Rajdip Mukherjee
Magnetic fields drive grain boundary migration in non-magnetic systems through anisotropic susceptibility, yet how the local orientation can affect the resulting collective grain growth behavior remains unclear. We employ a phase-field model to investigate magnetic-field-assisted grain growth in the diamagnetic Bi. This study provides a mechanistic basis for using static and dynamically varied magnetic fields to control texture development and grain growth kinetics in weakly magnetic materials. We also identify the conditions under which magnetic-field-driven orientation selection produces a distinct bimodal grain-size distribution. The bicrystal studies establish that boundary migration is governed by the magnetic free-energy difference between differently oriented grains, while polycrystalline field-sweep simulations reveal a transition from capillary-dominated coarsening to magnetically biased texture selection. For unbiased orientation distributions, magnetic selection remains distributed; however, when a small population of grains is strongly favored, the driving force localizes and exhibits bimodal coarsening characterized by enlarged favored grains embedded within a fine-grained matrix, even without grain boundary energy anisotropy, particle pinning, or heterogeneity. The field removal and field reorientation simulations further show that magnetic field history can redirect the coarsening pathway.
Materials Science (cond-mat.mtrl-sci)
Topological Magnetism in 2D and 3D: Skyrmions and Hopfions. Classical and quantum approaches
New Submission | Other Condensed Matter (cond-mat.other) | 2026-10-19 20:00 EDT
We discuss the properties of ferromagnetic skyrmions in relation to the Dzyaloshinskii Moriya interaction, nonlinear sigma models, merons, vortices, frustration, and dipole dipole interactions. Particular attention is given to skyrmion skyrmion interactions and to the dynamical equations governing magnetic textures, including the Landau Lifshitz Gilbert, Thiele, and Landau Lifshitz Bloch equations. The review subsequently extends the discussion to antiferromagnetic systems and to topological structures in three dimensions, with emphasis on Hopfions and their topological characterization. We then examine quantum skyrmions, including approaches that go beyond the semiclassical description, and discuss the emergence of quantum Hopfions. The theoretical framework is complemented by appendices presenting analytical solutions and ansatzes for skyrmions, spin coherent states and path integrals, quantum antiferromagnets, spin torques, fiber-bundle concepts and the Hopf map, and the Euler Lagrange formalism in three dimensions. By connecting continuum field theory, magnetic dynamics, topology, and quantum mechanics, this review aims to provide a coherent framework for understanding the formation, stability, dynamics, interactions, and quantum properties of topological magnetic textures across different dimensions and magnetic systems.
Other Condensed Matter (cond-mat.other)
115 pages, 20 figures
topas-editor and TOPilot: tools for AI-driven analysis of diffraction and total scattering data
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-19 20:00 EDT
John S. O. Evans, Oliver J. Wagstaff, Ivana R. Evans, Arnt Kern, Alan A. Coelho
This paper describes topas-editor and TOPilot, which provide a powerful interface to the TOPAS software suite and allow generative AI-driven automation of complex crystallographic tasks. topas-editor is a TOPAS-aware VS Code extension designed for the rapid creation and editing of TOPAS input files and for interacting with the software. It knows TOPAS syntax, has crystallographic-aware editing features and provides in-line user guidance via hover tips and automated links to reference manuals. TOPilot is a collection of Python routines and machine-accessible reference documents that allow AI-driven automated analysis in TOPAS. It uses a transferable topas-inp-writer skill that can be applied in all TOPAS application areas. We demonstrate the power and reliability of the approach using examples including: a complex Rietveld refinement with sample- and data-related complications; automatic analysis of multiple data sets; a pipeline from indexing through structure solution to refinement; automatic identification of the phases present in a sample; single crystal and powder diffraction analysis of incommensurate structures; and fitting PDF data. TOPilot can be used directly alongside topas-editor, via a stand-alone topilot-wizard, or via command line interfaces or desktop apps from major AI providers. TOPilot was developed and tested using Claude large language models, but can be configured to use other cloud or local models. topas-editor and TOPilot are freely available.
Materials Science (cond-mat.mtrl-sci)
submitted to Journal of Applied Crystallography
pymatgen: 15 years of community growth, new functionality, and future prospects
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-19 20:00 EDT
Janine George, Matthew K. Horton, Aaron D. Kaplan, Seán R. Kavanagh, Janosh Riebesell, Andrew S. Rosen, Haoyu Yang, Felix Adams, Mahdi Amachraa, Oxana Andriuc, Omar A. Ashour, Saurabh Bajaj, Ella Banyas, Luis Barroso-Luque, Karlo Berket, Noam Bernstein, Arpit Bhardwaj, Ali Hussain Umar Bhatti, Samuel M. Blau, Brandon Bocklund, Alexander Bonkowski, Danny Broberg, Guillaume Brunin, Kyle Bystrom, Charles A. Cardot, Rees Chang, Chi Chen, Wei Chen, Xin Chen, Yuan Chiang, Kamal Choudhary, Orion A. Cohen, Miguel D. Costa, Stephen T. Dacek III, Maarten de Jong, Tom Demeyere, Alan K. Dozier, Alexander Dunn, Shyam Dwaraknath, Maxwell T. Dylla, Kristjan Eimre, Alexander R. Epstein, Christina Ertural, Marco Esters, Matthew L. Evans, Johannes Falke, Adam Fekete, Bernard Field, Alexandr Fonari, Nathan C. Frey, Dale W. Gaines II, Alex M. Ganose, Matteo Giantomassi, Rhys E. A. Goodall, Petre-Flaviu Gostin, Aayush Gupta, Viet-Anh Ha, Geoffroy Hautier, Niclas Heinsdorf, Michael F. Herbst, Tingzheng Hou, Patrick Huck, Yuji Ikeda, Adam J. Jackson, Saivenkataraman Jayaraman, Finn R. Kearns, Sunghyun Kim, Ryan S. Kingsbury, Adam M. Krajewski, Yu Kumagai, Matthew C. Kuner, William T. Laderer, Weitang Li, Xiang-Guo Li, Yu Hsuan Liang, Hanyu Liu, Ke Liu, Miao Liu, Ahmad Lutfi, Olivier Marchand, Matthew J. McDermott, Bharat K. Medasani, Fanchen Meng, Kyle D. Miller, Henrique Miranda, Rohith Srinivaas Mohanakrishnan, Joseph H. Montoya, Guy C. Moore, Benjamin J. Morgan, Jason M. Munro, Koki Muraoka, Aakash A. Naik, Willis O’Leary, Anthony Onwuli, Jaesuk Park, Drew F. Parsons, Kai Pei, Guido Petretto, Thomas A. R. Purcell, Ji Qi
We present a retrospective on the Python Materials Genomics (pymatgen) library, reflecting on 15 years of community growth and established best practices. The current version of pymatgen builds on its robust, open-source foundation, emphasising its collaborative nature. Over the past decade, pymatgen has thrived as one of the largest open-source materials science codebases. We detail how pymatgen supports advanced computational materials science workflows, how it adapts to changing demands, and the lessons learned from its growing community, providing guidance beyond pymatgen’s open-source community. Pymatgen will continue to evolve in response to the current rapidly changing landscape of computational materials science and materials informatics. We discuss the challenges and potential solutions to managing the community-driven evolution of pymatgen and provide an outlook on its future development.
Materials Science (cond-mat.mtrl-sci)
Linear response for machine-learned interatomic potentials: phonons at arbitrary wave vectors from the primitive cell
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-19 20:00 EDT
Thalis H. B. da Silva, Hai-Chen Wang, Miguel A. L. Marques
Phonon calculations with machine-learned interatomic potentials are almost exclusively performed with finite displacements in supercells, an approach that is exact only at wave vectors commensurate with the supercell and whose error depends on the range of the force constants. In message-passing networks this range grows with the number of layers, and reaches 140 angstrom for the deepest universal models. Here we show that the dynamical matrix of a message-passing potential can be obtained exactly in the primitive cell, at any wave vector, as the linear response of the forces to a displacement modulated by a Bloch phase, in the spirit of density-functional perturbation theory. The phase enters only where the features of neighboring atoms are gathered, and the trained model is used without modification. One further derivative yields group velocities and mode Grüneisen parameters analytically. We apply the method to NequIP and Prophet, and reproduce the Hessians of supercells to machine precision. Using these results as a reference, we find that the supercells commonly employed in high-throughput calculations lead to errors of several tenths of a THz in the phonon frequencies, and that these errors decrease slowly with the size of the supercell, in particular for deep models. For a low-symmetry silicate, the supercell predicts a dynamical instability that the model does not have. Quantities that depend on derivatives of the dispersion, such as the group velocities and the Grüneisen parameter at low temperature, are considerably more affected than the frequencies themselves. When both approaches are used to obtain the same force constants, their computational cost is comparable for crystals with symmetry.
Materials Science (cond-mat.mtrl-sci)
Magnetic order in epitaxial (La2/3Sr1/3MnO3)3/(BaTiO3)3 trilayer heterostructures: Evidence for quasi-two-dimensional ferrimagnetism
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-19 20:00 EDT
E. Rebolini, H. Himanshu, K. Beauvois, S. Grenier, B. Mercey, B. Domenges, B. Ouladdiaf, C. Simon, M. B. Lepetit
The realization of artificial magnetic structures with high epitaxial quality and elevated critical temperatures remains a key challenge for spintronics. Here, we report the fabrication and characterization of epitaxial (La2/3Sr1/3MnO3)3/(BaTiO3)3 trilayer heterostructures grown by layer-by-layer laser ablation. High-resolution transmission electron microscopy, magnetization measurements, and neutron diffraction confirm their exceptional crystalline order and the absence of structural defects. Neutron diffraction reveals no antiferromagnetic Bragg peaks, ruling out most antiferromagnetic configurations with a non zero wave vector Q. Magnetic hysteresis loops instead evidence a ferromagnetic order with a remanent moment of about 0.5 bohr magneton per Mn atom at room temperature, persisting either in-plane or out-of-plane depending on the applied field. Our findings highlight neutron diffraction as a powerful tool for elucidating the magnetic structure of complex thin films and suggest that weak interlayer coupling through BaTiO3 leads to ferromagnetism with a high critical temperature (about 600 K).
Materials Science (cond-mat.mtrl-sci)
8 pages, 7 figures
Oxygen on Rh(100) revisited with ultra-high precision
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-19 20:00 EDT
Lutz Hammer, Tilman Kißlinger, Margareta Wagner, Reinhard B. Neder, Michael Schmid, Ulrike Diebold, M. Alexander Schneider
We have reanalyzed the 0.25 and 0.50 monolayer (ML) phases of oxygen on the catalytically important Rh(100) surface by quantitative low-energy electron diffraction (LEED), variable-temperature scanning tunneling microscopy (STM) and density functional theory (DFT). For both phases, the crystallographic structure could be determined by LEED structure analyses with single-digit picometer precision enabled by ultra-low Pendry R factors of R$ _\mathrm{P}$ $ \approx$ 0.07. For the (2$ \times$ 2)-O phase at 0.25 ML we find oxygen adsorbed at fourfold hollow sites in accordance to earlier results [Surf. Sci. 207 (1988) 55], however, with a pronounced buckling within the second layer of the otherwise unreconstructed substrate. For the 0.50 monolayer phase, we recently identified a (2$ \sqrt{2}$ $ \times$ 2$ \sqrt{2}$ )R45$ ^\circ$ -4O ground state structure [Phys. Rev. Res. 8 (2026) 023296], which decomposes into a large number of nano-domains already at temperatures below 100 K. In this paper we provide a detailed analysis of the atomic structure and the ordering behavior of this phase and resolve long-standing discrepancies with the original (2$ \times$ 2)pg model [Phys. Rev. Lett. 82 (1999) 4874]. We further prove by short-range order simulations that the coherent superposition of scattering contributions of the nano-domains leads to a virtual extinction of diffraction spots, which has concealed the true periodicity and symmetry of this phase for so long.
Materials Science (cond-mat.mtrl-sci)
Grain boundary strength and corrosion cracking susceptibility in TiN coatings under fission product segregation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-19 20:00 EDT
During fuel-cladding chemical interaction (FCCI), lanthanide fission products generated in the fuel can migrate into cladding grain boundaries (GBs), where segregation may reduce GB strength and promote corrosion cracking. We use first-principles segregation, decohesion, and bonding calculations to quantify Nd and Ce effects on six coincident-site lattice GBs in bcc Fe and TiN. For each material, segregation energies, work-of-separation values for complete interfacial cleavage, and traction-separation curves measuring ideal resistance to crack opening were evaluated within a consistent computational framework. Nd and Ce segregate favorably to both materials, and the median segregation energies are more negative in TiN, showing that TiN does not simply exclude these species from internal interfaces. The mechanical responses of Fe and TiN differ sharply. In Fe, Nd and Ce consistently reduce work of separation and peak traction, with median work-of-separation retentions of 0.72 and 0.65 and median peak-traction retentions of 0.47 and 0.43. In TiN, most decorated GBs preserve much of the clean response, with median work-of-separation retentions of 1.00 and 0.97 and median peak-traction retention of 0.85 for both fission products. Bonding analysis shows weak, occupied antibonding X-Fe replacement bonds in Fe, whereas the surrounding Ti-N network remains largely preserved after Nd/Ce segregation in TiN. These results provide atomistic support for the use of TiN and related nitride coatings to reduce FCCI damage by retaining GB strength if fission products segregate to coating internal interfaces. This retention of GB strength also provides a mechanistic descriptor for assessing coating susceptibility to FCCI-assisted corrosion cracking and environmentally assisted intergranular fracture.
Materials Science (cond-mat.mtrl-sci)
30 pages, 10 figures, 6 tables, plus Supplementary Information (2 figures, 3 tables)
Scalable long-range machine learning interatomic potentials with electrical response for atomistic material modeling
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-19 20:00 EDT
Yicheng Chen, Xiaoyun Yu, Hyejeong Song, Xintian Wang, Zihui Li, Zixi Xia, Junmin Chen, Peichen Zhong
Accurate atomistic simulations of materials under electric fields require long-range electrostatics and electrical-response modeling at length scales beyond the reach of conventional first-principles methods. Yet these capabilities remain difficult to reconcile with the scalability of machine-learning interatomic potentials (MLIPs). Strictly local models enable efficient spatial parallelization but neglect long-range interactions, whereas existing electrostatic extensions introduce global dependencies that hinder distributed computation. Here, we overcome this limitation by analytically separating the long-range electrostatic forces and Born effective charges (BECs) into a global electrostatics calculation and strictly local derivatives of learned latent charges. This formulation preserves the spatial decomposability of equivariant MLIPs while enabling distributed evaluation of energies, forces, stresses, and BECs across different boundary conditions. Implemented as DPA4C-LR on the \texttt{nvalchemi} platform, the framework scales to 5.2 million atoms on four GPUs at approximately twice the computational cost of its short-range backbone. Trained on energies and forces, DPA4C-LR accurately infers BECs and reproduces the field-dependent infrared spectra of water. We further demonstrate its capabilities by recovering the characteristic slim polarization hysteresis of relaxor \ce{Pb(Mg_{1/3}Nb_{2/3})O3}, which is obscured by finite-size effects in smaller simulations; predicting a room-temperature field-driven ionic conductivity of $ 6.8 \pm 0.7$ ~mS/cm in amorphous \ce{Li_{0.9}NbO_{0.9}Cl_{4.1}}; and modeling interfacial thermal transport across Si/diamond interfaces with slab-corrected electrostatics. By combining long-range physics, electrical-response inference, and distributed computation, this framework extends predictive atomistic modeling toward device-relevant length scales.
Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG)
Plastic Flow Rule Based on Dislocation Link Velocity
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-19 20:00 EDT
Hanfeng Zhai, Sh. Akhondzadeh, Ryan B. Sills, Nicolas Bertin, Wei Cai
We develop a theory for the plastic shear rate $ \dot{\gamma}_i$ on each slip system $ i$ of face-centered cubic (FCC) single crystals, by integrating the shear rate contributions $ \dot{\gamma}_i(l)$ from dislocation links of length $ l$ . A generalized Orowan equation expresses $ \dot{\gamma}_i(l)$ in terms of the link density $ n_i(l)$ and the average link velocity $ v_i(l)$ . This model accurately reproduces the discrete dislocation dynamics (DDD) shear-rate data for all 12 slip systems across 99 loading orientations. In particular, it explains why the plastic shear rate depends exponentially on the resolved shear stress $ \tau_i$ , as reported previously, in the absence of any thermally activated mechanism. This dependence arises from the exponential tail of $ n_i(l)$ filtered through the threshold-like velocity function $ v_i(l)$ . Furthermore, $ v_i(l)$ is well approximated by a single two-dimensional function $ v(\tau_i,l)$ for all these slip systems. The link velocity is therefore governed mainly by $ \tau_i$ and $ l$ , with only a minor effect from the complex interactions between slip systems. These interactions instead manifest themselves mainly through $ n_i(l)$ . As a demonstration of the effect of the link-length distribution on the slip rate, we show that even when $ \tau_i$ is limited to a narrow window, the shear rates still span two orders of magnitude. The supply of long links is therefore the dominant factor controlling slip-system activity, outweighing the direct effect of $ \tau_i$ on the link velocity.
Soft Condensed Matter (cond-mat.soft), Mathematical Physics (math-ph), Computational Physics (physics.comp-ph)
Finite-temperature phase diagram of dipolar bosons in a cylindrical setup
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-10-19 20:00 EDT
Juan Sánchez-Baena, Raúl Bombín, Jordi Boronat
Temperature plays a non-trivial role in dipolar systems, being able to either induce or destroy spatial density modulations. In order to shed light into the interplay between thermal effects and quantum correlations, we employ the path integral Monte Carlo method (PIMC) to obtain the phase diagram of a system of dipolar bosons in an infinite cylindrical geometry and at finite temperatures. For a fixed total density, we vary the scattering length of the interaction and the temperature, and characterize the structure and superfluidity of the emerging phases. The PIMC method accounts for thermal effects and quantum correlations at all orders, and can be used to quantitatively estimate the superfluid fraction of the system. Remarkably, we find a regime of parameters where, starting from a supersolid, the spatial order vanishes with temperature before the superfluidity does. We also find a region of the phase diagram where the superfluid fraction displays a non-monotonous dependence with temperature. Our results extend previous descriptions, relying on Bogoliubov theory, to larger temperatures in the thermodynamic limit and illustrate how spatial modulations and superfluidity are lost as temperature is increased.
Quantum Gases (cond-mat.quant-gas)
6 pages, 4 figures
Spatial and Temporal Control of Avalanches in Dense Active-Passive Mixtures
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-19 20:00 EDT
Caterina Landi, Giulia Janzen, Chantal Valeriani, Ezequiel Ferrero, Daniel A. Matoz-Fernandez
Dense active–passive mixtures are often described within an effective-temperature picture, in which active dopants promote cage breaking and fluidize an arrested amorphous host. However, at sufficiently large persistence, the same dopants drive stress accumulation and localized void formation. Here we investigate the avalanche dynamics across this progression, focusing on the intermediate regime between dynamic arrest and void formation, where the system remains structurally homogeneous on average but relaxes through intermittent collective rearrangements rather than as a simple activated liquid. Using overdamped simulations of dilute active dopants embedded in a dense amorphous solid, we show that the avalanche dynamics separates into distinct spatial and temporal controls. For a given system size, the active fraction sets the size of the largest stress-release events, with a cutoff that grows as the square root of the fraction of dopants, $ S_c\sim \phi_a^{1/2}$ , i.e., with the number of mean dopant spacings across the system, whereas persistence controls how avalanches unfold in time at fixed released stress. A decomposition of the stress into active and passive contributions, together with measurements of avalanche participation and morphology, shows that the active minority provides a localized and persistent driving channel while the surrounding amorphous packing carries the collective stress release. While the active minority controls the cutoff of the avalanche size statistics and the timing of the stress releases, the long-range elastic response and the building correlations in the passive host sets the size exponent, $ \tau_S\simeq1.1$ , that is shared with externally sheared and uniformly active amorphous solids.
Soft Condensed Matter (cond-mat.soft)
Symmetry constraints on magnon-induced dynamics of skyrmion helicity in frustrated magnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-19 20:00 EDT
Gabriel Mayor, Christina Psaroudaki
The helicity of a magnetic skyrmion in a centrosymmetric frustrated magnet is a soft collective coordinate and a candidate variable for encoding quantum information. Its coherence is ultimately influenced by coupling to the magnon environment, which is commonly incorporated only phenomenologically. Here we combine a microscopic Keldysh treatment of the helicity–magnon coupling to resolve the contribution of individual magnon modes to the effective helicity dynamics. In the U(1)-symmetric model, the magnon bath generates, to leading order, a reactive helicity mass renormalization. When U(1) symmetry is broken, additional direct helicity–magnon couplings become allowed. In the presence of finite magnon lifetimes, these couplings generate an Ohmic contribution to the low-frequency helicity dynamics. The spatial symmetry of the perturbation determines which magnon sectors contribute to this damping, providing mode-resolved selection rules for the helicity–magnon coupling. Thus, we establish a microscopic connection between helicity dynamics and the excitation spectrum of frustrated skyrmions and identify the symmetry constraints governing dissipation of helicity-based quantum states.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
Learning the self-energy through equivariant neural networks
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-19 20:00 EDT
Wudong Shen, Yang Zhong, Min-Ye Zhang, Xinyang Dong, Hongjun Xiang, Xinguo Ren
The electronic self-energy determines the single-particle Green’s function and, through it, quasiparticle energies and spectral functions, but computing it from first principles is expensive and it is a difficult machine-learning target: complex-valued, matrix-valued in a local-orbital basis, and dependent on a continuous frequency. We predict the dynamical correlation part of the imaginary-frequency G_0W_0 self-energy matrix of molecules from atomic species and coordinates with an E(3)-equivariant message-passing network, the rotational covariance of the orbital-space matrix being imposed by the architecture itself and the static exchange part taken from the density-functional reference. Frequency enters either as an explicit network input or through frequency-specific output heads, and the predicted matrices are continued to the real axis in a representation in which causality and a non-negative spectral density hold by construction. The frequency-conditioned model reproduces matrix elements to below 1 meV on the imaginary axis for the systems studied here, and that accuracy survives the continuation: for water clusters, including a tetramer absent from the training set, and for chemically diverse molecules from QM9, the reconstructed spectral functions follow the G_0W_0 reference peak by peak and the frontier quasiparticle levels are recovered to a few tens of meV. Learning the self-energy on the imaginary axis is therefore a practical route to real-frequency spectra: once the model is trained, and given the density-functional reference it is built on, a new geometry costs no explicit G_0W_0 calculation.
Materials Science (cond-mat.mtrl-sci)
Magnetic tunnel junctions of twisted La2/3Sr1/3MnO3 freestanding bilayers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-19 20:00 EDT
Kota Kanda, Shiho Irie, Kodai Niitsu, Masayuki Ochi, Takumi Yamazaki, Kouta Kondou, Kohei Ueda, Takeshi Seki, Jobu Matsuno, Junichi Shiogai
Transition metal oxides (TMOs) host a variety of emergent spintronic or multiferroic functionalities owing to the intricate interplay between lattice, orbital, charge, and spin degrees of freedom. Recent advances in epitaxial lift-off and dry transfer techniques using water-soluble sacrificial layers enables stacking and twisting of freestanding membranes of such strongly correlated oxides, providing even richer physical properties and functionalities. To date, the twisted junctions of TMOs have been mainly investigated in insulators, focusing on their structural and dielectric properties. Here, we demonstrate that the twisted bilayer membranes of La2/3Sr1/3MnO3, a prototypical half-metallic ferromagnetic metal TMO, offer a magnetic tunnel junction (MTJ) with their van der Waals (vdW) gap acting as a tunnel barrier. The twisted junctions of La2/3Sr1/3MnO3 exhibit tunnelling magnetoresistance (TMR) effect with respect to relative orientation of magnetizations of top and bottom membranes. In addition, high-field magnetoresistance shows uniaxial anisotropy, which can be assigned to tunnelling anisotropic magnetoresistance (TAMR) effect reflecting rhombohedral distortion of fully-relaxed La2/3Sr1/3MnO3. The demonstration of TMR and TAMR effects suggests that spin and in-plane momentum degrees of freedom of 3d electrons are conserved across the twisted junctions of TMOs, opening a new avenue for realizing strongly correlated twistronics utilizing electron coherence through tunnelling processes.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el), Applied Physics (physics.app-ph)
28 pages, 4 figures, and supplementary information
Intercalation of Ultrathin Ferromagnetic Iron Films at the Graphene/SiC Interface
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-19 20:00 EDT
Niels Rösch, Rico Ehrler, Stefanie Suzanne Brinkman, Xin Liang Tan, Anders Christian Mathisen, Marc Stevens, Sascha Hermann, Olav Hellwig, Philip Schädlich, Hendrik Bentmann, Susanne Wolff, Thomas Seyller, Fabian Göhler
The intercalation of high-quality PASG-grown (polymer-assisted sublimation growth) zero-layer graphene on 4H-SiC(0001) with iron is studied using a deposition-and-annealing approach. We find that unlike other metals, Fe does not easily intercalate, and the intercalation procedure has to be balanced with the formation of iron silicides and graphitic carbon at the interface. After successful intercalation, the ultrathin iron films are protected against oxidation by the covering graphene sheet, and retain ferromagnetic behaviour with an in-plane easy axis even at room temperature. When exposed to a selenium-rich atmosphere at elevated temperatures, an almost complete exchange of Fe by Se is observed, imposing a major restriction for the formation of multi-element 2D compounds via sequential intercalation schemes.
Materials Science (cond-mat.mtrl-sci)
Analysis of Transient Microscopy Data in Reciprocal Space
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-19 20:00 EDT
Thomas J. Sheehan, William A. Tisdale
Transient microscopy has evolved to include a family of well-established techniques for studying the spatiotemporal dynamics of excited states in a variety of materials systems. In these methods, a laser pulse is focused to locally excite a material, and the subsequent evolution of the excited species is visualized to extract transport parameters such as diffusivities. Typically, transport coefficients are extracted from experimental datasets using curve-fitting methods to analyze the change in the mean squared displacement (MSD) of the spatial profiles over time. However, this approach can lead to inaccurate or misleading diffusivity values under many common experimental conditions, and is only formally accurate for the case of a single diffusing species. In this work, we introduce a new approach to the analysis of transient microscopy data based on the evolution of profile shapes in reciprocal space. We use simulated datasets to quantitatively analyze the performance of our proposed methods and compare them to current state-of-the-art analysis techniques. We demonstrate that reciprocal-space-based analysis methods have the highest overall performance in terms of accuracy and precision for normal diffusive transport over a range of realistic initial conditions and signal-to-noise ratios. Furthermore, we highlight the limitations of using MSD alone to characterize anomalous transport in materials, and we show how analysis of spatial frequencies can yield a more comprehensive understanding of complex excited-state dynamics and their underlying physical mechanisms. Our results show that reciprocal-space-based analysis methods are powerful tools for characterizing and quantifying many different types of transport behaviors.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
Type 1.5 vortex bags in single component Ginzburg-Landau models with higher order potentials
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-19 20:00 EDT
Martin Speight, Thomas Winyard
We demonstrate the existence of type 1.5 like superconductivity in a single component Ginzburg-Landau model with a higher order potential. The model exhibits two competing superconducting Meissner states (MS), each of which has its own pair of length scales (coherence length and penetration depth). The solutions take the form of bags that contain vortices of one vacuum inside the other. This gives rise to four different types of vortex interaction, where one set of length scales determines vortex interactions inside the bags and the other set between the bags. Hence, within the bag the vortices can repel or attract and the bags themselves can repel or attract depending on the hierarchy of four length scales. When vortices repel within the bag, solutions act similarly to those in type 1.5 multicomponent superconductors, but in a single component system.
Superconductivity (cond-mat.supr-con)
16 pages, 5 figures
Limits from nonlinear loss of spin-orbit-torque control of magnon transport
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-19 20:00 EDT
Lerato Takana, Katya Mikhailova, Charles Zheng, Sauviz Alaei, Xiangcheng Liu, Junwei Tong, Kwangyul Hu, Michael Flatté, Xiaoqin Li, Yuri Suzuki
Controlling magnon currents is central to the development of magnonic devices, which exploit spin excitations for information transport without charge flow. Here, we use the spin-orbit torque (SOT) from a Pt gate to control the effective magnon damping in three-terminal devices fabricated from low-damping lithium aluminum ferrite (LAFO) thin films and identify the nonlinear damping that ultimately limits the gate response. With increasing gate current, the nonlocal magnon signal initially increases, but saturates and subsequently decreases above a critical gate current density. Brillouin light scattering microscopy reveals that this turnover coincides with the emergence of an SOT-driven auto-oscillation mode localized beneath the gate, whose frequency continuously redshifts with increasing gate current, characteristic of large-amplitude nonlinear dynamics, and with a suppression of the propagating magnon population away from the gate. Micromagnetic simulations reproduce the observed nonmonotonic gate response only when an amplitude-dependent effective damping is included, indicating that nonlinear losses, rather than saturation of spin injection, limit the degree of magnon modulation. Our results show that SOT compensation of magnon damping is ultimately limited by nonlinear damping attributed to auto-oscillations, providing a framework for understanding the limits of magnon current modulation in magnetic insulators.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Temperature and Thickness Dependent Spin Current Transmission through Epitaxial Antiferromagnetic α-Fe2O3
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-19 20:00 EDT
Koushik Prabhakara, Rajeev Nepal, Subhashree Chatterjee, Rabindra Basnet, Ezana Negusse, Ramesh C Budhani
Antiferromagnetic insulator {\alpha}-Fe2O3 is a potential medium for coherent motion of spin waves over relatively large distances, allowing non-dissipative transfer of information between circuit elements. However, the structural defects and temperature dependent spin reorientations in this oxide impact the propagation. Understanding how the magnetic state of an antiferromagnetic insulator affects spin-current transmission is therefore important for elucidating the mechanisms governing spin transport. Here, we report spin-current transmission through epitaxial {\alpha}-Fe2O3 thin films sandwiched between Permalloy and Pt. Using spin pumping and inverse spin Hall effect, we observe a finite symmetric dc voltage across the Pt layer over the temperature range 1.6 to 300 K for alpha-Fe2O3 thicknesses of 0, 30, 40, and 100 nm. The symmetric voltage coefficient Ks exhibits two approximately linear temperature regimes, separated by a characteristic temperature T\ast whose value depends on the thickness of the {\alpha}-Fe2O3 layer. Further, the dc magnetization measurements on some of the samples suggest that the T\ast is correlated with the spin reorientation transition (Morin transition) in {\alpha}-Fe2O3. Interestingly, a significantly larger magnitude of dKs/dT is noted below the characteristic temperature T\ast. The observed thickness and temperature dependent spin-current transmission indicates a sensitivity to the magnetic state of the insulating hematite layer.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Scaling of entanglement with distance between subsystems: detection of phase transitions in the $t’$-$π$-flux model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-19 20:00 EDT
Maksim Ulybyshev, Gergő Roósz, Gabriele Bellomia, Karsten Held, Fakher Assaad, Frederic Bippus
The system-size scaling of bipartite entanglement can be used to detect phase transitions. We develop a related approach for strongly correlated electron models where large density matrices or large system size scaling are inaccessible. To this end, we demonstrate that phase transitions of various kinds are signaled by a sharp signature in the first- or second-order logarithmic derivatives of the negativity measuring entanglement between small clusters at varying distances. Crucially, we show how to mitigate the effect of quantum Monte Carlo noise at large distances when computing the negativity. Our focus is on the $ t’$ -$ \pi$ -flux Hubbard model using auxiliary-field quantum Monte Carlo simulations. It has the particular advantage of showing three distinct phase transitions in a single model: semimetal to band insulator, semimetal to antiferromagnetic Mott insulator, and a magnetic order-disorder transition belonging to the Gaussian, Gross-Neveu, and O(3) Wilson-Fisher universality classes, respectively.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
20 pages 18 figures
Engineering nonrelativistic spin splitting in semiconductors by altermagnetic proximity
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-19 20:00 EDT
Altermagnets combine vanishing net magnetization with momentum-dependent, nonrelativistic spin splitting, offering functionalities attractive for spintronics and quantum devices. Their practical use, however, is constrained by the limited availability of materials that simultaneously possess the required altermagnetic symmetry, semiconducting electronic structure, and weak spin-orbit coupling. Here we show that these requirements can instead be separated between constituent materials through proximity engineering. We develop an analytical theory for a conventional semiconductor coupled to a gapped $ d$ -wave altermagnet and demonstrate that virtual tunneling transfers the altermagnetic spin splitting to the semiconductor. Crucially, the induced nonrelativistic and relativistic spin splittings exhibit qualitatively different dependences on band alignment. Virtual processes involving the valence and conduction bands of the altermagnet can reinforce the altermagnetic splitting while contributing with opposite signs to the interfacial Rashba coupling. Consequently, electrostatic tuning can access a regime in which the Rashba splitting vanishes while a sizable $ d$ -wave spin splitting persists. Exact diagonalization of the full heterostructure model confirms the analytical theory and establishes the robustness of this mechanism beyond the perturbative regime. Our results identify altermagnetic proximity as a route for engineering nonrelativistic spin-split electronic states in established semiconductor platforms, providing a general strategy for disentangling magnetic and relativistic spin interactions in quantum heterostructures.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Transport and thermalization under noncommuting localized constraints
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-19 20:00 EDT
Amir Nesturov, Attila Takács, Lenart Zadnik
We investigate the effects of spatially localized conserved quantities on transport and thermalization in quantum and classical many-body systems. We consider several related models: the integrable quantum Volterra model, its nonintegrable classical limit, and two cellular automata derived from the latter. Although localized constraints are often associated with lattice gauge theories, our models do not admit such an interpretation. In systems with discrete degrees of freedom, these constraints induce uniform fragmentation of the Hilbert or configuration space. In the quantum Volterra model, we derive an exact mapping of the dynamics within each Hilbert-space fragment onto a quantum chiral Potts chain. We find that energy transport is ballistic, with identical transport coefficients across all fragments. In the nonintegrable classical limit, energy transport is diffusive, and we similarly find the diffusion constant to be independent of whether or not the constraints are fixed (resolved). Finally, in the cellular automata, we show that, despite leaving transport unaffected, localized constraints lead to a strong breakdown of local ergodicity.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
12 pages, 4 figures
Sampling the XY model with an attention-based neural network
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-10-19 20:00 EDT
Piotr Białas, Christian D. Morales, Tomasz Stebel, Dawid Zapolski
We present a transformer-based variational autoregressive network for sampling lattice systems with continuous degrees of freedom and apply it to the two-dimensional XY model near the Berezinskii-Kosterlitz-Thouless transition. The architecture is combined with physics-informed ingredients: locality-informed attention and approximate probabilities. The resulting sampler significantly outperforms existing neural samplers. We train the model on lattices up to $ 96\times96$ , verify with a mode-dropping estimator that no parts of the configuration space are missed, and reproduce the energy, magnetization and helicity modulus obtained with the traditional Markov Chain Monte Carlo algorithm.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech), Machine Learning (cs.LG), High Energy Physics - Lattice (hep-lat)
19 pages, 6 figures
Anti-synchronized collective rotation in magnetic colloidal particles under rotating magnetic fields
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-19 20:00 EDT
Adithya Bharath, A. V. Anil Kumar
Collective synchronization is a common response of interacting magnetic particles subjected to rotating external fields. Here we demonstrate a distinct nonequilibrium state in a two-dimensional cluster of magnetic colloidal particles in which the ordered crystalline core rotates, on average, opposite to the direction of the applied rotating magnetic field, while the defect-rich outer region continues to rotate with the drive. We term this state anti-synchronized collective rotation. By combining structural, spectral, bond-resolved, and layer-resolved torque analyses, we show that anti-synchronization is associated with a broader defect-rich interface, enhanced and dynamically heterogeneous bond deformation, and a reorganization of torque transmission between the surface and the crystalline interior. In the synchronized state, steric torques compensate the opposing dipolar contribution in the outer core, maintaining a positive net interaction torque. In the anti-synchronized state this compensation becomes insufficient, producing a negative net torque in theouter core and enabling core-surface rotational decoupling. Increasing the driving frequency restores coherent rotation through a transition characterized by competing positive- and negative-angular-velocity populations and hysteresis, consistent with a discontinuous, first-order-like dynamical transition. These results demonstrate how deformation and spatial redistribution of interaction torques can generate counter-rotating collective states in driven colloidal matter.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
21 pages, 16 figures
Orbital Angular Momentum Currents and Textures in a Multiorbital Double Helix
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-19 20:00 EDT
Danny Cordova, Edwin Vásconez, Ernesto Medina
The microscopic origin of chirality induced spin selectivity (CISS) in biomolecular structures has traditionally been discussed in terms of spin orbit coupling and spin angular momentum. However, orbital angular momentum (OAM) is increasingly recognized as a more direct electronic response to molecular chirality. A helical hopping network built only from s orbitals can support an itinerant orbital moment and an orbital Edelstein response, but such a basis has no local atomic OAM and therefore omits the complementary contribution arising from coherence among active p orbitals. Here we construct a six-band multiorbital double helix model parameterized by characteristic B form DNA geometry and hopping scales. The model incorporates major minor groove asymmetry, an axial base pair offset representing stagger, and compositional inequivalence between the two strands, providing structural control parameters with which the orbital response can be tuned. Inter strand hybridization generates a full three component atomic OAM texture in the corotating local helical frame, including a radial component absent in the corresponding single helix model. We separately evaluate the itinerant OAM using the Bloch wave packet formulation of orbital magnetization and identify an additional inter-strand circulation channel unique to the double-helix connectivity. The resulting atomic and itinerant responses have distinct microscopic origins, magnitudes, and temperature dependences, establishing a multiorbital framework for geometry controlled angular momentum generation and transport in chiral molecular conductors.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
16 pages, 9 figures. Submitted to the Physical Review
Anyonic Neural Network Wavefunctions
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-19 20:00 EDT
Andres Perez Fadon, Pok Man Tam, Leyna Shackleton
The macroscopic behavior of a non-interacting gas of Abelian anyons has remained unsettled for many decades. Prior numerical methods employing exact diagonalization in the continuum and on the plane have been limited to small system sizes, at most $ N = 4$ anyons. Using the rapidly developing technology of neural network wavefunctions, we develop variational ansatze appropriate for studying continuum models of the Abelian anyon gas. The neural network architecture, which we call “AnyNet”, is capable of exactly enforcing the non-analytic short-distance behavior induced by the anyonic statistics. We demonstrate excellent agreement with exact diagonalization for $ N=4$ anyons, obtain accurate results up to $ N = 16$ for intermediate statistics, and study up to $ N=20$ for almost-fermionic anyons, matching perturbative results within a 0.4% discrepancy. We use this methodology to study anyons in a harmonic trap, and anyonic atoms as a model for anyon binding to impurities. We study the structure of anyonic wavefunctions as the statistics parameter is varied. We focus on the single-particle density, the pair density, the angular momentum, and the scaling of the wavefunction as multiple anyons coalesce. This work opens doors to understanding the macroscopic behavior of anyons, for which rich phases have been predicted theoretically.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Gases (cond-mat.quant-gas), High Energy Physics - Theory (hep-th), Quantum Physics (quant-ph)
32 pages (21 main text), 12 figures
Ionic switching between supermagnetic states
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-19 20:00 EDT
Sumaiyatul Ahsan, Yin-Ju Yen, Andrew H. Comstock, Tanya A. Balandin, Jason D. Azoulay, Jamie H. Warner, Dario A. Arena, Faisal M. Alamgir
Supermagnetic states are typically set during synthesis. Changing and retaining these states requires sustained external stimulus. Without resynthesis or continued stimulus, we show, for the first time, a reversible magneto-ionic switching between superferromagnetic (SFM) and superspin-glass (SSG) states using room-temperature Li-ion transport. We utilize the incomplete lithiation of NiO into nanoscale Ni and Li2O to switch between the states. Lithiation generates a fragmented nano-Ni network that strengthens dipolar interactions and promotes SFM order with stronger memory and higher room-temperature moments. Delithiation partially regenerates NiO and drives the system into an SSG state with higher low-temperature coercivity and sharper temperature-selective memory. The interconversion between SFM and SSG persists at all measured subsequent lithiation-delithiation cycles, creating a general framework for supermagnetic switching.
Materials Science (cond-mat.mtrl-sci)
11 pages, 4 figures, 27 pages of supporting information