CMP Journal 2026-09-08
Statistics
Nature Materials: 1
Nature Nanotechnology: 2
Nature Physics: 1
Science: 1
arXiv: 79
Research Square: 2
Nature Materials
Single-crystalline CoSi semimetals with high conductivity and reliability
Original Paper | Electronic devices | 2026-09-07 20:00 EDT
Jiewei Chen, Jianmin Yan, Lingwei Fan, Tao Zheng, Xiangli Che, Chaoyi Zhu, Wei Lu, Ming Deng, Yat Hon Ng, Zhaoqing Wang, Yi Wan, Xixi Jiang, Ye Zhu, Zhongmin Yang, Kevin J. Chen, Bor-Wei Liang, Kai-Shin Li, Yann-Wen Lan, Lain-Jong Li, Yang Chai
As the size of state-of-the-art copper interconnects shrinks to the nanoscale, carrier scattering greatly increases their resistance, causing signal delay and reliability issues. Alternative conductors are therefore needed to sustain interconnect scaling beyond conventional charge-transport mechanisms. Here we demonstrate CoSi semimetal for highly scalable, conductive and reliable interconnects. As the CoSi thickness decreases from 1 µm to ∼20 nm, its resistivity decreases from 7.0 to 0.72 μΩ·cm due to the highly conductive surface path. The room-temperature resistivity of 20-nm-thick CoSi is one-tenth that of copper at the same thickness. The high cohesive energy (5.4 eV) and migration barrier (3.7 eV) of CoSi confer excellent reliability at current densities of up to 108 A cm-2 and temperatures up to 450 °C. Radiofrequency measurements demonstrate CoSi interconnect operation at frequencies up to 40 GHz. We further integrate a CoSi interconnect with a 16-nm-node silicon ring oscillator, which operates at the same frequency as its metal-interconnected counterpart.
Electronic devices, Electronic properties and materials
Nature Nanotechnology
Structured light-matter interaction in semiconductor cavity quantum electrodynamics
Original Paper | Quantum information | 2026-09-07 20:00 EDT
Shunfa Liu, Jiantao Ma, Hanqing Liu, Yangpeng Wang, Xueshi Li, Haiqiao Ni, Zhichuan Niu, Kai Zou, Yun Meng, Xiaolong Hu, Xuehua Wang, Jin Liu
A cavity quantum electrodynamics system consisting of a confined single photon and a single quantum emitter serves as a fundamental block for quantum optics and photonic quantum technologies. The canonical optical mode used in the conventional cavity quantum electrodynamics features a uniform polarization distribution, leading to the scalar light-matter interaction in most existing experiments. Despite the rapid progress in the generation of structured light with spatially varied polarizations, the structured light-matter interaction, especially at the single-quanta level, is highly intriguing yet largely unexplored. Here we present the structured light-matter interaction at the single-photon level in a semiconductor cavity quantum electrodynamics system. Four distinct structured cavity modes that are spectrally close to each other are constructed in a micropillar cavity. By spatially locating a single epitaxial quantum dot (InAs quantum dot) at the periphery of a semiconductor micropillar cavity and spectrally tuning the quantum dot emission wavelength into the resonances of the structured cavity modes, cavity-enhanced single-photon emissions with spin-locked chiral orbital angular momentum and engineerable spin-orbit entanglements are achieved within a single wavelength-scale device. Our work opens different ways of exploring structured quantum light-matter interactions in chiral quantum optics and high-dimensional photonic quantum technology.
Quantum information, Quantum optics, Single photons and quantum effects
Charge-switching ionizable lipids lower the toxicity of lipid nanoparticles
Original Paper | Drug delivery | 2026-09-07 20:00 EDT
Dengpan Liang, Yalin Qi, Hesong Han, Negar Ahmadian, Kewa Gao, Kaycee Sapasap, Yuxi Zhang, Silin Guo, Atip Lawanprasert, Sopida Pimcharoen, Sheng Zhao, Milan T. Del Buono, He Xia, Zoe O. Enders, Benjamin W. Burgstone, Antonino Calio, Neel Dankar, Bingwei Lu, Lei S. Qi, Aijun Wang, Niren Murthy
Lipid nanoparticles (LNPs) have great potential as nucleic acid delivery vehicles; however, they trigger the production of inflammatory cytokines, which limits their medical applications. Developing non-inflammatory LNPs is challenging because the LNP’s ionizable lipid and the process of endosomal disruption are the major sources of LNP toxicity but are also essential for delivering nucleic acids. Here we demonstrate that ionizable lipids containing a carboxylic acid and an amine (termed S-lipid) switch their charged state between the pHs of 7.4 and 4.0, allowing them to generate LNPs (termed switchable nanoparticles) that efficiently encapsulate nucleic acid and trigger endosomal release without activation of the TLR4, complement, galectin-8 and platelet activating factor signalling pathways. Finally, we demonstrate that switchable nanoparticles are better at treating lipopolysaccharide-induced acute lung injury than traditional LNPs because they do not exacerbate pre-existing inflammation. Collectively, these results demonstrate that negatively charged ionizable lipids can mitigate the toxicity of LNPs.
Drug delivery, RNA nanotechnology
Nature Physics
A cascaded random access quantum memory
Original Paper | Quantum information | 2026-09-07 20:00 EDT
Ziqian Li, Eesh Gupta, Fang Zhao, Riju Banerjee, Yao Lu, Tanay Roy, Andrew Oriani, Andrei Vrajitoarea, Srivatsan Chakram, David I. Schuster
Dynamic random access memory is critical to classical computing but notably absent in current superconducting quantum processors. Integrating high-coherence memory units would enable resource-efficient control of logical qubits and allow the separate optimization of logic and storage subsystems. Here we realize an eight-bit cascaded random access quantum memory. We use a single transmon to classically address seven memory modes while isolating them from processor nonlinearities by introducing a buffer layer between the processor and a multimode storage cavity. We demonstrate arbitrary random access with an average infidelity of less than 1.5% per mode and characterize the many-body interactions that dominate the error budget. This architecture enables a significant reduction in control lines per logical qubit and supports transversal operations within the memory module, establishing a scalable unit cell for fault-tolerant quantum architectures.
Quantum information, Quantum physics
Science
Stereoselective polysubstituted bicyclo[1.1.0]butane synthesis by rhodium-catalyzed kinetic resolution
Research Article | 2026-09-08 03:00 EDT
Xiaolong Zhang, Rongkai Wu, Zhaohong Liu, Ge Yin, Jiaqi Tang, Paramasivam Sivaguru, Xin Hong, Edward A. Anderson, Xihe Bi
Bicyclo[1.1.0]butanes (BCBs) are a distinctive class of strained small-ring carbocycles of growing importance in synthetic and medicinal chemistry. However, the enantioselective synthesis of polysubstituted BCBs remains a largely unsolved challenge. Herein, we report a general chemical platform for the stereoselective assembly of chiral or meso 1,2,3,4-tetrasubstituted BCBs from internal alkynes and carbenes via stepwise [2+1+1’] or one-pot [2+1+1] cycloaddition reactions, respectively. Successful execution of these transformations exploits the combination of triftosylhydrazones (carbene precursors) and chiral dirhodium catalysts. The sterically hindered catalyst Rh2(R-3,5-diPheTPCP)4 features a confined chiral microenvironment that enables exquisite discrimination between cyclopropene enantiomers, affording highly enantioenriched polysubstituted BCBs through kinetic resolution upon reaction with chiral rhodium carbenes. This chemistry operates under mild reaction conditions, employs readily available starting materials, and exhibits broad substrate scope.
arXiv
Reproducible capillary fluctuation analysis of solid-liquid interfaces for stiffness and anisotropy calculations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-07 20:00 EDT
Kai Liu, Douglas E. Spearot, Damien Tourret
The capillary fluctuation method (CFM) is widely used to compute solid–liquid interfacial properties from atomistic simulations, but its accuracy depends on choices in interface construction, wave-vector selection, sampling, and simulation geometry. Here, we develop a diagnostics-driven workflow for reproducible CFM calculations using pure Al as a representative system. Employing both ribbon models and thick two-dimensional references, we show that apparent linearity of the fluctuation spectrum alone does not ensure reliable stiffness or anisotropy estimates. Instead, a reliable CFM analysis requires a fitting window consistent with both temporal sampling and continuum capillary-wave assumptions, systematic sensitivity tests of the interface identification procedure, explicit propagation of replica variability, and independent verification of model-thickness convergence. We further propose a practical thickness-selection rule based on coexistence-temperature consistency, which enables finite-size effects to be controlled while retaining the substantial computational efficiency of ribbon geometries. By making the main sources of uncertainty explicit and diagnosable, the proposed workflow improves the reliability of the CFM as a quantitative tool and provides a foundation for its broader application to complex solid–liquid interfaces.
Materials Science (cond-mat.mtrl-sci)
Exact quantum spin liquids with topological order on maple-leaf and trellis lattices
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-09-07 20:00 EDT
Li Ern Chern, Roderich Moessner, Claudio Castelnovo
We construct spin models with bond-dependent anisotropic interactions on the penta-coordinated maple-leaf and trellis lattices, which yield exact $ \mathbb{Z}_2$ quantum spin liquids akin to the Kitaev honeycomb model. We characterize the resulting ground states by their flux sectors, Chern numbers, and topological excitations. Using replica exchange quantum Monte Carlo simulations, we find that the gauge fluxes are ordered at sufficiently low temperatures such that every unit triangle has $ \pm \pi/2$ -flux, where the sign is uniform across the system, and every unit hexagon (square) has $ 0$ -flux ($ \pi$ -flux) within the parameter space of interest. We map out the topological phase diagram for each model, which reveals parameter regimes hosting $ \mathbb{Z}_2$ and Ising topological orders, and we derive an analytical expression for the mass term of the Majorana fermions, the vanishing of which indicates a transition between these phases. We further establish the correspondence between individual vortices (i.e., flux excitations) and two species of anyons in the dimer limit, overcoming the obstacle faced by degenerate perturbation theory in treating odd-length elementary plaquettes. Interestingly, we find that two dimer limits of the maple-leaf model with distinct assignments of anyon species can be smoothly connected to each other in the vortex-free sector, but they are separated by fermion-gap-closing transitions in certain two-vortex sectors.
Strongly Correlated Electrons (cond-mat.str-el)
11+12 pages, 6+5 figures
The influence of quantum geometry on the phase boundary and collective excitations of electron liquids and crystals
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-09-07 20:00 EDT
Paul Froese, Mark R. Hirsbrunner, Yong Baek Kim
Recent experiments on multilayer graphene systems have reinvigorated the study of electron crystallization, now with the inclusion of quantum geometry. In this work, we apply time-dependent Hartree-Fock (TDHF) to the $ \lambda$ -jellium model to analyze the impact that quantum geometry has on the electronic liquid–crystal phase diagram and how it modifies the collective modes and responses of the liquid and crystal phases. In agreement with recent results utilizing neural quantum states, we find that quantum geometry favours electron crystallization, shifting the transition to higher densities. We also study the instabilities revealed by TDHF in the Fermi liquid ground state at low densities, providing insight into the fluctuations driving the crystallization transition. We further find that quantum geometry reduces the dispersion of the plasmon mode and suppresses Friedel oscillations deep in the liquid phase. Resolving the density response in terms of individual orbitals, we find that this suppression is caused by spectral weight transfer to an out-of-phase inter-orbital mode. Finally, we show that an analogous mode that emerges in the crystal phase corresponds to the breathing mode of an emergent real-space pseudospin skyrmion lattice.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
(18 pages, 8 figures)
Quantum oscillations of helical edge states of periodically deformed 2D topological insulator in magnetic field
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-09-07 20:00 EDT
A. V. Tsvetkova, P. D. Grigoriev, Ya. I. Rodionov
We study edge-state transport in a two-dimensional topological insulator with a periodically deformed edge subjected to a uniform magnetic field. Zeeman coupling breaks time-reversal symmetry and enables elastic backscattering, producing oscillations of the forbidden-band widths. In the strong-field regime, the gaps can close completely at discrete field values. In the weak-field regime, we identify an important class of periodic deformations for which the dominant semiclassical scattering is controlled by complex infinity rather than by the nearest turning points. We develop a semiclassical treatment of this process and establish its agreement with perturbation theory and direct numerical calculations. The gap modulation should produce observable oscillations of the edge conductance. Unlike conventional magnetic quantum oscillations, which are periodic in inverse field, the predicted oscillations are periodic in the magnetic field itself, with a period determined by the Fermi velocity and effective g-factor
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Mathematical Physics (math-ph)
33 pages, 19 figures
Dual Charge-Density-Waves in Two-dimensional DyTe3 and Their Distinct Impacts on Magneto-Transport Properties
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-09-07 20:00 EDT
Shuvankar Gupta, Yasemin Ozbek, Olajumoke Oluwatobiloba Emmanuel, Maya Bostock, Johnathan Kowalski, Pengpeng Zhang, Xianglin Ke
Charge-density-waves (CDWs) are macroscopic quantum states defined by periodic modulations in electronic charge density coupled with lattice distortions. Despite significant research efforts, the evolution of electromagnetic transport properties in the presence of CDWs remains largely unexplored. Here, we report the effects of two orthogonal CDWs (CDW1 and CDW2) coexisting at low-temperature in DyTe3 on its electronic transport properties. Importantly, we find that while no clear magnetotransport anomaly is resolved across CDW1 transition under the present experimental conditions, the emergence of CDW2 drives a drastic enhancement in magnetoresistance and a multiband-governed nonlinear Hall response. These results demonstrate that CDW1 and CDW2 in DyTe3 are fundamentally different and impact its electronic transport in qualitatively distinct ways, establishing DyTe3 as a model system for understanding the transport consequences of multiple CDWs in quasi-two-dimensional materials.
Strongly Correlated Electrons (cond-mat.str-el)
4 Figures
Journal of Materials Chemistry C (2026)
Fukui-Kawakami chains: spectrum and hidden $\mathfrak{gl}(1|1)$-symmetry
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-09-07 20:00 EDT
Rob Klabbers, Antoine Lefebvre
Fukui and Kawakami showed that the trigonometric Haldane–Shastry (HS) spin chain can be deformed by introducing twisted boundary conditions. In this work we revisit the resulting twisted HS chains, which we call Fukui–Kawakami (FK) chains.
We analyse their spectra in dependence of the twist parameter, utilising a direct connection with the (untwisted) HS chain. This allows us to explain why part of the spectrum can be described by Fukui and Kawakami’s twisted Bethe equations, and can be constructed from Yangian highest weight states. These states can be labelled by combinatorial data called motifs', as in the HS chain, which cover some of the (deformed) descendants. We furthermore show that there are other descendants which do not follow from these Bethe equations, but whose energy can be described as a sum of two single-particle energies, suggesting additional hidden symmetries. We then focus on the special case of antiperiodic boundary conditions, and show that this chain coincides with the minimally polarised’ long-range model recently introduced by Basu-Mallick, Finkel, and González-López. Remarkably, this connection implies that the antiperiodic chain has a hidden $ \mathfrak{gl}(1|1)$ -symmetry, which we use to relate the HS motifs to their `supersymmetric’ $ \mathfrak{gl}(1|1)$ counterparts.
Statistical Mechanics (cond-mat.stat-mech), Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Theory (hep-th), Mathematical Physics (math-ph)
16 pages, 4 figures
Speed-quality tradeoff in a physical model of molecular sorting
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-09-07 20:00 EDT
Elisa Floris (1 and 2), Damiano Andreghetti (2 and 3), Thibaut Caplet (2, 3 and 4), Luca Dall’Asta (2, 3 and 5), Andrea Gamba (2, 3 and 5) ((1) Department of Biology, University of Graz, Graz, Austria, (2) Institute of Condensed Matter Physics and Complex Systems, Department of Applied Science and Technology, Politecnico di Torino, Torino, Italy, (3) Istituto Nazionale di Fisica Nucleare (INFN), Italy, (4) Université Paris-Saclay, ENS Paris-Saclay, DER de Physique, Gif-sur-Yvette, France, (5) Italian Institute for Genomic Medicine (IIGM) and Candiolo Cancer Institute IRCCS, Candiolo, Italy)
Eukaryotic cells rely on membrane-mediated processes to compartmentalize biomolecules, counteracting diffusion-driven homogenization. These processes involve the selective sorting and packing of molecules into lipid vesicles, which are then dispatched to appropriate intracellular destinations. Previous works introduced an abstract statistical physics framework for studying this molecular distillation process, where the membrane was treated as static and the focus was on molecular aggregation and extraction. Here, we extend this framework to explicitly incorporate dynamic membrane behavior, including bending, curvature generation, and changes in membrane size due to vesicle fusion and fission events. Sorting domains drive membrane curvature, leading to vesicle formation, detachment, and a molecular distillation process that alters membrane size. Using mesoscopic modeling and numerical tools, we investigate the resulting interplay between membrane mechanics and molecular sorting. We determine a well-defined parameter region where vesicle fission and efficient molecular sorting occur, controlled by membrane rigidity, spontaneous curvature, and pressure difference across the membrane. We further identify a trade-off between speed and quality of molecular distillation: parameters that accelerate vesicle formation tend to reduce the quality of distillation, and vice versa. We propose maximization of the rate of negative entropy production as a natural criterion to optimally balance these competing effects. In this context, optimal parameters emerge naturally from the coupled dynamics of molecular aggregation and membrane mechanics, suggesting a possible strategy for cellular sorting systems to strike an efficient balance between rapid vesicle formation and high sorting quality.
Soft Condensed Matter (cond-mat.soft)
Accelerating Atom Simulations with Variable-Block Sparse Matrix Library
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-07 20:00 EDT
Modern atomistic simulations increasingly employ localized orbitals to represent quantum operators, yielding sparse block matrices whose block shapes vary with chemical species and basis choice. Conventional scalar sparse formats store the entries of each block individually, obscuring this local structure and limiting the use of efficient block algorithms. We present VBCSR, a distributed sparse matrix library that preserves variable-size atomic blocks and accelerates the core linear algebra of large-scale atomistic simulations. A unified interface automatically maps scalar, uniform-basis, and multispecies operators to compressed sparse row (CSR), block sparse row (BSR), or variable-block compressed sparse row (VBCSR). Our advanced acceleration method groups blocks of equal shape and dispatches them to optimized dense kernels. In the reported benchmarks, VBCSR outperforms the tested Python-accessible reference implementations for several block-sparse benchmarks. We further demonstrate VBCSR in an InP nanoparticle application containing more than (10^6) atoms.
Materials Science (cond-mat.mtrl-sci), Distributed, Parallel, and Cluster Computing (cs.DC), Quantum Physics (quant-ph)
8 pages, 4 figures
Composition-dependent nonlinear viscoelastic-viscoplastic behavior and constitutive framework for digitally mixed polymers spanning the glass transition
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-09-07 20:00 EDT
Multi-material PolyJet printing produces voxel-scale digital mixtures of an elastomeric photopolymer (Agilus) and a glassy photopolymer (Vero), giving a material family whose room-temperature response ranges from elastomeric to glassy; a unified description spanning the family has remained challenging. Large-deformation uniaxial compression over nearly three orders of magnitude in strain rate reveals a nonlinear, rate-dependent load-unload response that evolves continuously with composition, from recoverable elastomeric hysteresis to glassy yield with post-yield softening, hardening, and substantial residual strain. Dynamic mechanical analysis (DMA) shows that each mixture has a single glass transition temperature ($ T_g$ ) that shifts to higher temperature with both Vero fraction and frequency, so composition acts much as temperature or loading rate does. This time-composition equivalence motivates one constitutive structure for the whole family rather than a separate property set per mixture: an equilibrium hyperelastic network with three non-equilibrium, rate-dependent branches carrying reptational, intermolecular, and glassy resistance. Its properties are anchored at the two endpoints and interpolated by smooth composition scaling laws. The model captures the compression response of all seven calibrated compositions and predicts a withheld mixture from the scaling laws alone. Resolving the predicted stress into its branches shows the load passing from the elastomeric to the glassy mechanism, and the work from elastic storage to dissipation, as Vero content and rate rise. The glass transition that DMA maps at small strain therefore governs the large-strain deformation mechanisms. The framework gives a compact, physically based description of digitally mixed polymers and a predictive basis for designing functionally graded, architected multi-material structures.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
16 figures
Triboelectrification of a dense metal-organic framework for resilient mechanical energy harvesters
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-07 20:00 EDT
Chuzhan Jin, Debayan Mondal, Jiahao Ye, Jin-Chong Tan
Triboelectric nanogenerators (TENGs) incorporating metal-organic frameworks (MOFs) have largely been designed around porous architectures, based on the assumption that high internal surface area is the primary driver for triboelectric enhancement. Herein, we demonstrate that a dense, nominally nonporous MOF called ZIF-zni can instead function as an effective high-loading filler within a tribopositive polyurethane (PU) matrix, offering a design strategy for harnessing interfacial electromechanical effects. A 20 wt% ZIF-zni@PU composite delivers an output voltage of 470+/-15 V and a peak power density of 1.31+/-0.03 W m-2 against polydimethylsiloxane (PDMS). The device exhibits stable performance over ~94,000 cycles under a contact force of ~100 N, and it remains operational under higher impact beyond 500 N. This concept enables the demonstration of a proof-of-concept triboelectric floor tile. Combined experimental and theoretical studies indicate that the performance enhancement arises from favourable interfacial polarization, reduced dielectric screening, and surface accessible ZIF-zni rich domains, rather than porosity alone. These features are accompanied by reduced work of adhesion and modified surface roughness, hence improving contact electrification. These findings establish dense MOFs as an effective triboelectric filler and identify interfacial electronic structure and polarization as key design parameters for engineering mechanical energy harvesters and self-powered sensors.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
30 pages, 6 figures, supporting information
Calculation of DFT Spin-Orbit Spillage with Quantum ESPRESSO
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-07 20:00 EDT
Duy Quan Nguyen, Paul C. H. Li
This work describes the calculation of spin-orbit spillage from a crystal structure. Spin-orbit spillage provides a measure of the likelihood that a material has topological character. The spillage also provides the reference quantity for the machine-learning classifier of Choudhary et al., which predicts whether the spillage exceeds a specified threshold rather than the calculation of its numerical value directly. The complete computation workflow was applied to the insulating compound BaMg2Bi2, yielding a spillage of 2.094 compared with the published VASP spillage of 2.075, corresponding to a difference of 0.9%. The calculation is described in terms of two Quantum ESPRESSO (QE) calculations of spillage performed with and without spin-orbit coupling, the role of relativistic pseudopotentials, and the subsequent wavefunction-overlap analysis. The limitations of the same calculation procedure for semimetals are also examined.
Materials Science (cond-mat.mtrl-sci), Quantum Physics (quant-ph)
22 pages, 1 figure, 7 tables
Layer Architecture Shapes Electronic, Magnetic, and Lattice Interactions in Ruddlesden-Popper Nickelates
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-09-07 20:00 EDT
W. He, X. Guo, X. Luo, J. Thomas, J. Sears, Sophia F. R. TenHuisen, Ziqiang Guan, Xinglong Chen, D. A. Dahlbom, B. Zager, J. Pelliciari, Yi-Feng Zhao, H. LaBollita, Hong Zheng, M. K. Lajer, J. F. Mitchell, V. Bisogni, A. S. Botana, M. Mitrano, S. Johnston, M. P. M. Dean
The discovery of superconductivity in Ruddlesden-Popper nickelates has raised a central question: how does layer architecture shape the electronic, magnetic, and lattice interactions relevant to pairing? Here, we report a detailed comparative study of the two polymorphs of La3Ni2O7–the alternating monolayer-trilayer (LNO-1313) and bilayer (LNO-2222) structures–and the related trilayer compound La4Ni3O10, using both Ni L3- and O K-edge RIXS. We find that LNO-1313 and La4Ni3O10 share strikingly similar electronic, magnetic, and lattice excitations, whereas bilayer LNO-2222 exhibits distinct features. Compared to LNO-2222, LNO-1313 and La4Ni3O10 have weaker orbital polarization, enhanced 3d8L character, a reduced out-of-plane magnetic-exchange scale, and stronger EPC. Within an effective local-moment framework, an entangled-dimer scenario provides a natural description of the spin excitations generated by strong antiferromagnetic interlayer coupling. Its advantage over conventional spin-wave theory is clearest in bilayer LNO-2222, where the interlayer coupling dominates the intralayer interactions. These findings provide critical experimental constraints for future theoretical models for the low-energy physics relevant to superconductivity in these layered nickelates.
Strongly Correlated Electrons (cond-mat.str-el)
10 pages, 5 figures, not including references and additional material
From Single-Chain Dynamics to Structure Formation: Dynamic Self-Consistent Field Theory and Molecular Dynamics of (Co)polymer Melts across Entanglement Regimes
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-09-07 20:00 EDT
Alireza F. Behbahany, Jafar Charghalizadeh, Friederike Schmid
Dynamic self-consistent field theory (DSCFT) provides an efficient continuum framework for studying structure formation in inhomogeneous polymer systems, but its predictive accuracy depends on the choice of the nonlocal mobilities. Here, we construct mobility functions for moderately and strongly entangled homopolymer and diblock copolymer systems from the relaxation dynamics of single-chain structure factors, based on molecular dynamics (MD) simulations of the Kremer-Grest model and analytical reptation theory. Single- chain mobilities are combined such that the resulting DSCFT accounts for the dependence of fluxes on local chain densities. The theory is then applied to the spinodal decomposition of symmetric homopolymer blends and diblock copolymer melts following a quench into the (micro)phase-separation regime. Predictions of DSCFT are systematically compared with MD simulations. Mobility functions derived from single-chain dynamics are found to reproduce the kinetics of structure formation more accurately than conventional Debye-type mobilities. We additionally investigate the influence of adding stochastic currents (noise) that are correlated according to the fluctuation-dissipation relation. At low noise levels, they enable the generation of equilibrium initial states and facilitate defect annealing. At high noise levels, however, nonolinear effects lead to discrepancies between DSCFT and MD simulations.
Soft Condensed Matter (cond-mat.soft)
Structural tuning of reduced exciton mass in layered HOIP compounds: Causation vs. correlation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-07 20:00 EDT
Isaac R. Burkholder, Cindy Y. Wong, André Schleife, Kameron R. Hansen, John S. Colton, Branton J. Campbell
Reduced exciton mass ($ \mu$ ) was recently reported to correlate strongly with a framework distortion in a series of nine single-layer (2D) metal-halide perovskite (HOIP) compounds. Specifically, $ \mu$ was observed to increase in tandem with an alternating PbI4 octahedral tilt about an in-plane axis. In this work, we use group representation theory to decompose the observed framework distortions into displacive symmetry modes of a common high-symmetry parent framework. We find that all nine distorted frameworks involve linear combinations of the same six symmetry modes, which have been reported to contribute to the framework distortions of a wide range of HOIP compounds. We show that these modes have highly correlated impacts on the band structure. To differentiate causation from correlation, we vary the amplitude of each mode independently and use density-functional theory to determine the resulting electronic band structures, from which $ \mu$ is extracted. We find that bond-transverse displacements of the equatorial halide atoms increase $ \mu$ , while bond-transverse displacements of the apical halide atoms decrease it. Bond-axis displacements appear to have little or no effect on $ \mu$ . Our results demonstrate three new structure-property relationships, revealing a promising new avenue for exciton engineering in layered perovskite materials.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
27 pages, 14 figures. For associated SI information, see DOI https://doi.org/10.5281/zenodo.22261753
A discrete crack-tip theory for nonlinear lattice networks
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-09-07 20:00 EDT
Jiabin Liu, Shaoting Lin, Juntao Huang
Crack-tip fields govern deformation localization and failure initiation. Classical continuum fracture mechanics describes these fields through theories such as the Hutchinson-Rice-Rosengren (HRR) field for nonlinear power-law solids. However, continuum descriptions break down near cracks in soft and architected materials, where load is transmitted through discrete chains, fibers, or struts. Here, we develop a discrete crack-tip theory for lattice networks with nonlinear chains. The theory has two central components. First, at large deformation, the strain of a representative chain in layer $ i$ depends approximately linearly on the applied macroscopic strain, $ \varepsilon_i\approx k_i(\lambda-1)$ , defining a layer-dependent strain-amplification factor $ k_i$ . Second, along topology-selected chain directions, termed discrete HRR lines, the layer-to-layer ratios of $ k_i$ follow a two-regime scaling law. Together, for a power-law chain force-strain relation with exponent $ p$ , the inner discrete regime predicts $ \varepsilon_i\sim i^{-1/p}$ and $ f_i\sim i^{-1}$ , which differs from the classical continuum HRR prediction. The theory also explains why the intrinsic fracture energy approaches a size-independent limit as the network size increases. Photoelastic hydrogel experiments further validate our theory. These results reveal a two-regime crack-tip scaling law in nonlinear lattice networks and provide a framework for predicting chain deformation and intrinsic fracture energy.
Soft Condensed Matter (cond-mat.soft)
Metallic Organometallic and Semiconducting Covalent Phases of Free-Standing $γ$-Graphdiyne Molecular Wires
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-07 20:00 EDT
Antony G. L. Rodrigues, Guilherme S. L. Fabris, Bruno Ipaves, Fábio L. L. de Mendonça, Douglas S. Galvão, Marcelo L. Pereira Junior
One-dimensional carbon allotropes combining sp and sp2 hybridizations provide a versatile platform for atomically precise quantum wires with tunable electronic, vibrational, and mechanical responses. Recent on-surface synthesis has realized the $ \gamma$ -graphdiyne molecular wire on Au(100) in two interconvertible phases sharing an identical aromatic backbone but distinct linkage chemistry: an organometallic intermediate with C-Au-C bridges and a fully covalent product with diacetylenic linkages. While experimental techniques characterize the on-surface periodicity and C$ \equiv$ C Raman signatures, the intrinsic properties of the free-standing wires remain inaccessible. Here, we address this gap using hybrid-functional first-principles calculations. The covalent phase is a semiconductor with a direct band gap of 2.02 eV, a polyynic bond-length alternation of 0.117 Å, and a chain periodicity reproducing experiment within -0.5%. Conversely, the organometallic phase exhibits partial cumulenization and 1D metallic behavior, with spin channels crossing the Fermi level. Both isolated polymers demonstrate dynamic stability with Young’s moduli of 995 nN and 861 nN, respectively, where the C-Au-C bridge acts as a soft link absorbing 9.2% of axial deformation at +6% macroscopic strain. Species-resolved vibrational analysis identifies an effective-conjugation-coordinate band at 1408 cm$ ^{-1}$ for the covalent phase and Au-projected modes below 400 cm$ ^{-1}$ for the intermediate, offering diagnostic fingerprints for phase discrimination during thermal or chemical conversion.
Materials Science (cond-mat.mtrl-sci)
32 pages, and 5 figures
Initialization-free ultralow-power programmable spin-orbit torque logic devices enabled by chirally asymmetric switching
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-07 20:00 EDT
Spin logic is of great interest for the development of high-performance, non-Von Neumann artificial intelligence chips. Of particular advantage is the programmable spin-orbit torque logic that can achieve the complete set of the 16 Boolean logic operations within a single device in an initialization-free, low-power, and scalable manner, which is, however, a challenge despite remarkable efforts over more than two decades. Here, utilizing chirally asymmetric switching, we demonstrate an initialization-free, low-power, programmable spin-orbit torque logic device that is capable of the complete set of 16 Boolean logic operations within a single device with only three inputs and ultralow power of < 1 fJ/bit. We also propose the first initialization-free, all-electrical spin-based cascading computing devices, including a half adder, a three-level full adder, a two-level full adder, and a Transfer/NOT selector. These compact and scalable computing devices are enabled by the chirally asymmetric spin-orbit torque switching of a Ta/FeCoB bilayer with a significant perpendicular Dzyaloshinskii-Moriya interaction field. These results pave an intriguing way for the development of next-generation high-performance large-scale in-memory computing chips based on chirally asymmetric spin-orbit torque switching.
Materials Science (cond-mat.mtrl-sci)
Demonstration of room-temperature, magnetic-field-free, and ultralow-power spin-orbit torque logic device based on composition-uniform van der Waals magnet Fe3GaTe2
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-07 20:00 EDT
Zhengxiao Li, Qianbiao Liu, Wenliang Zhu, Lijun Zhu
Van der Waals magnets have received blooming interest in material science and spintronics for the advantages of low magnetization, flexible stacking, strong tunability, and dangling-bond-free interfaces. However, there has been no report of room-temperature magnetic-field-free spin logic device based on a van der Waals magnet. Here, we demonstrate a room-temperature, field-free, low-power, scalable spin-orbit torque in-memory computing logic device utilizing a van der Waals magnet Fe3GaTe2 bit with strong perpendicular magnetic anisotropy and a Pt channel with strong spin Hall effect, high electrical conductivity, and electric asymmetries. Current pulse width-dependent switching measurement reveals a low intrinsic critical magnetic-field-free switching current of 1.8e7 A cm-2, a high thermal stability factor of 50, and the potential of an ultralow write power of 1.5 fJ per bit at 1 ns pulse width for a typical industrial-level device dimensions (40 times lower than the industrially optimized W/FeCoB device). These results suggest a great potential of van der Waals magnets in dense, ultralow-power, scalable in-memory computing technologies.
Materials Science (cond-mat.mtrl-sci)
Light alkali metal functionalized two-dimensional C5N monolayers for enhanced hydrogen storage
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-07 20:00 EDT
Gom Dorji, Sonam Peden, Syed Faraz Hasan, Kondo-Francois Aguey-Zinsou, Tanveer Hussain
This work presents a density functional theory (DFT) investigation of a two-dimensional (2D) C5N monolayer functionalized with Li, Na, and K for hydrogen storage. Pristine C5N exhibits weak H2 adsorption, while alkali-metal functionalization significantly enhances its storage capability. The C5N monolayer can stably accommodate up to six metal dopants, with binding energies stronger than the corresponding cohesive energies, indicating resistance to metal aggregation. Ab initio molecular dynamics simulations further confirm the thermal stability of the functionalized systems at 300 K. Charge transfer from the metal dopants to C5N enhances polarization and strengthens H2 adsorption. Each dopant can adsorb up to eight H2 molecules, yielding a maximum of 48 H2 molecules per unit cell and gravimetric storage capacities of 9.42, 8.61, and 7.93 wt% for Li-, Na-, and K-functionalized C5N, respectively. The average H2 adsorption energies of -0.16 to -0.17 eV/H2 indicate moderate interactions suitable for reversible storage. Thermodynamic analysis further demonstrates favourable H2 adsorption/desorption under practical operating conditions, while desorption-temperature, recovery-time, and volumetric analyses support the potential reversibility and storage performance of these systems. Overall, alkali-metal-functionalized C5N emerges as a promising 2D material for efficient and reversible H2 storage.
Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
25 pages, 7 figures and 4 tables
Hydrogen Storage on Transition-Metal-Decorated Nitrogen-Modified Carbon Nanoribbons
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-07 20:00 EDT
Gom Dorji, Amrutha M, Brahmananda Chakraborty, Sonam Peden, Syed Faraz Hasan, Shabbir Ahmad Tanveer Hussain
Recently synthesized carbon nanoribbons (CNRs) were investigated for hydrogen (H2) storage using first-principles density functional theory calculations. Pristine CNRs exhibited weak H2 adsorption; therefore, the host structure was modified by substituting carbon atoms at the C-H edges with 12 nitrogen atoms, followed by Mn and Y doping to enhance H2 binding. A maximum of five metal atoms could be accommodated on the 12N-CNRs. Electronic structure analysis revealed strong orbital hybridization between the metal atoms and the CNRs, while binding energy calculations confirmed the structural stability of the doped systems. Bader charge analysis further quantified the charge transfer between the metal atoms and the host structure. The average H2 adsorption energies were calculated to be -0.40 eV/H2 for the Mn-doped system and -0.25 eV/H2 for the Y-doped system, which are within the desirable range for reversible hydrogen storage. The maximum theoretical gravimetric storage capacities at 0 K reached 7.48 wt% for the Mn-doped system and 6.55 wt% for the Y-doped system. Under practical conditions of 30 atm and 298.15 K, the storage capacity of the Y-doped system decreased to 6.04 wt%, whereas the Mn-doped system maintained its full capacity of 7.48 wt%. Thermodynamic analysis indicated that H2 adsorption is favored at low temperatures and high pressures, while desorption becomes feasible at elevated temperatures and lower pressures. These results demonstrate that Mn- and Y-doped CNRs satisfy key U.S. Department of Energy requirements for reversible H2 storage and show promise as potential hydrogen storage materials under near-ambient conditions.
Materials Science (cond-mat.mtrl-sci)
23 pages, 7 figures
Enhanced Multifractality Induced by Non-Hermitian Disorder in Quantum Percolation
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-09-07 20:00 EDT
W. S. Oliveira, Julian Faundez, Rodrigo Arouca, Welles Morgado
We investigate the interplay between geometric dilution and non-Hermitian disorder in the two-dimensional quantum site-percolation model. Non-Hermiticity is introduced through random imaginary on-site potentials, representing spatially uncorrelated gain and loss, while the hopping amplitudes remain reciprocal. By combining complex level-spacing statistics, participation entropy, and multifractal analysis, we characterize the localization properties of the eigenstates as functions of the disorder and the non-Hermiticity strength. Our finite-size scaling results show that non-Hermitian disorder shifts the quantum percolation threshold ($ p_q$ ) toward larger occupation probabilities. Consequently, the fully delocalized phase is progressively suppressed and disappears at sufficiently strong disorder. This suppression is not a simple consequence of adding on-site disorder of a given strength, but is specifically enhanced by its imaginary character, as an equally strong real (Hermitian) on-site potential produces a weaker shift of $ p_q$ . Nevertheless, the intermediate region between the classical ($ p_c$ ) and quantum percolation thresholds presents a genuine multifractal critical phase, while the localization-length exponent $ \nu$ remains the same, relative to its Hermitian value. Altogether, our results demonstrate that random gain and loss enhance the multifractal regime while preserving the universality class of the quantum percolation transition.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
Evidence of Crystal-Field-Mediated Anisotropic Orbital Rashba Effect in Epitaxial Ru/FM Heterostructure
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-09-07 20:00 EDT
Yu Zhang, Wenhao Niu, Yumin Yang, Wenqi Xu, Gengchen Meng, Hailong Wang, Na Lei, Dahai Wei
Electrical generation of orbital angular momentum provides a promising route to current-induced torques, yet effective control of orbital Rashba textures still remains challenging, particularly because the role of the interfacial crystal field remains largely unexplored. Here, we report experimental evidence for a crystal-field-mediated interfacial anisotropic orbital Rashba effect (AORE) in epitaxial Ru/ferromagnet heterostructures. Total orbital torque was disentangled into an isotropic bulk contribution and an in-plane anisotropic interfacial contribution. The latter was strongly suppressed by degrading the crystallinity of either constituent and by inserting a Cu spacer, highlighting the essential roles of coherent interfacial orbital hybridization and direct Ru/ferromagnet contact. These results identify interfacial crystal-field coherency as a key ingredient in manipulating orbital Rashba textures and establish a route toward engineering the symmetry and directionality of orbital torques.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
7 Pages, 4 Figures
4 MV/cm (010) $β$-Ga$_2$O$_3$ Heterojunction Diodes Realized by Low-Damage e-Beam NiO$_x$ Interlayers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-07 20:00 EDT
Carl Peterson, Yizheng Liu, Chinmoy Nath Saha, Rachel Kahler, Akhila Mattapalli, Sriram Krishnamoorthy
We report on the utilization of a low-damage e-beam NiO$ _x$ deposition process to realize field-plated heterojunction diodes (FP-HJDs) on (010) $ \beta$ -Ga$ _2$ O$ _3$ films with high critical breakdown field strengths beyond 4 MV/cm and power figure of merits (PFOM) of >1 GW/cm$ ^2$ . Diodes were fabricated on a 2.67 $ \times$ 10$ ^{16}$ cm$ ^{-3}$ intentionally doped 6.2 $ \mu$ m thick epitaxial layer grown by metalorganic chemical vapor deposition (MOCVD) on a conductive Sn-doped $ \beta$ -Ga$ _2$ O$ _3$ (010) substrate using TMGa, O$ _2$ , Ar carrier gas, and SiH$ _4$ as the silicon dopant source. The mesa etched FP-HJD devices utilized a thin 7 nm e-beam NiO$ _x$ interlayer before the sputtered NiO$ _x$ layers to eliminate the effects of sputter-induced ion damage on the (010) epilayers. Current-Voltage measurements resulted in a forward current density of 700 A/cm$ ^2$ at 4 V, HJD ideality factor of 1.29, a V$ _{bi}$ of 2 V, rectification ratio of 10$ ^{11}$ , and a differential specific on resistance (R$ _{on,sp}$ ) value of 2.36 m$ \Omega$ $ \times$ cm$ ^2$ . Breakdown of the (010) FP-HJDs was 1.64 kV, leading to a parallel plane electric field at breakdown (E$ _{||,max}$ ) of 4.02 MV/cm and a PFOM of 1.14 GW/cm$ ^2$ , which is a state-of-the-art result for diodes on MOCVD-grown (010) drift layers.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
19 pages, 7 figures
Breakdown of the Overdamped Approximation in Fluctuating Environments
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-09-07 20:00 EDT
Kazuki Fukutani, Takuma Akimoto
The overdamped approximation is widely used to describe Brownian motion in complex environments, but its validity becomes nontrivial when the friction coefficient itself fluctuates in time. We investigate this problem by comparing underdamped and overdamped Langevin dynamics subject to the same fluctuating friction and satisfying the fluctuation–dissipation relation at a common temperature. We show that environmental averaging and inertial elimination generally lead to different long-time transport when environmental fluctuations are fast compared with velocity relaxation. For rapidly fluctuating friction, the underdamped dynamics is governed by the arithmetic mean friction and yields $ D_{\rm eff}^{\rm under}=k_{\rm B}T/\langle\gamma\rangle$ , whereas the overdamped dynamics gives $ D_{\rm eff}^{\rm over}=k_{\rm B}T\langle\gamma^{-1}\rangle$ . For a two-state Markov friction, we derive the finite-time effective diffusion coefficient exactly and identify the full crossover between these two regimes, controlled by the competition between velocity relaxation and environmental switching. We further establish the fast-fluctuation result for general stationary friction processes and verify it for a continuous log-Ornstein–Uhlenbeck environment, for which the characteristic crossover time can also be determined independently. Our results reveal a noncommutativity between environmental averaging and inertial elimination, establish a timescale-dependent criterion for the validity of overdamped dynamics in temporally heterogeneous environments, and show that rapid environmental fluctuations can enhance, rather than suppress, the consequences of inertia.
Statistical Mechanics (cond-mat.stat-mech)
15 pages, 3 figures
Mean-field theory for quantum spin chains
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-09-07 20:00 EDT
Mylène Martirosyan, Astrid Monin-Baroille, Leïla Moueddene, Mohammed M. Shabat, Bertrand Berche
Mean-field theory is a widely used approximation for describing phase transitions, particularly effective above the upper critical dimension. Its origins can be traced back to the van der Waals theory of the liquid-gas transition and Weiss’s molecular field theory of the paramagnetic-ferromagnetic transition. However, it was Lev D. Landau who provided a unifying and general framework applicable to a broad class of physical systems. The mean-field approach typically involves neglecting thermal fluctuations, which is a reasonable assumption in many classical contexts. However, its application to quantum phase transitions at zero temperature is less common. The aim of this short pedagogical paper is to explore and clarify the use of the mean-field approach in the less familiar domain of quantum phase transitions. We specifically consider the Ising model and the Blume-Capel model.
Statistical Mechanics (cond-mat.stat-mech)
Scaling laws and energy dissipation in the dynamics of SLE curve as a 1D turbulence model
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-09-07 20:00 EDT
In this study, we demonstrate the characteristics of the stochastic Loewner evolution (SLE) as a one-dimensional (1D) turbulence model. First, we show that the diffusion process $ x(t)$ obtained by the time coordinate change in the SLE becomes the time dependent diffusion process that satisfies Richardson’s law of this http URL, we derive the condition on the diffusivity parameter $ \kappa$ such that the diffusion process $ x(t)$ satisfies Kolmogorov’s 4/5th law, which determines the relation between the mean energy dissipation and velocity in the particles of turbulence. Further mathematical analysis showed that this condition is seen as the condition on Loewner entropy $ S_{\mathrm{Loew}}$ , which includes the white Gaussian noise term $ W_{s}$ in the Loewner driving function of the present model. In addition, the numerical simulations were performed to verify the scaling relations of this 1D turbulence model. These results suggest that the standard SLE becomes a beneficial model of 1D turbulence by introducing an appropriate time coordinate change and imposing the conditions on $ \kappa$ and $ S_{\mathrm{Loew}}$ .
Statistical Mechanics (cond-mat.stat-mech), Mathematical Physics (math-ph)
13 pages, 3figures
Interlayer Exciton Condensate Stiffness Is Non-Monotonic in Quantum Metric
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-09-07 20:00 EDT
Bo Zou, Yitong Zhang, Siddhartha Sarkar, Shi-Zeng Lin, Allan H. MacDonald, Kai Sun
Identifying the origin of the superfluid stiffness of electron-electron and electron-hole pair condensates is an important issue in flat-band physics. Here, we study the stiffness of bilayer exciton condensates using exact diagonalization and realistic Coulomb interactions across a wide variety of flat Chern band systems, including Landau levels, mixed Landau levels, and moiré bands. We find that stiffness is non-monotonic in the trace of the quantum metric and that it develops peaks when the band wavefunctions are engineered to be similar to those of Landau levels. The stiffness predicted by mean-field theory agrees quantitatively with exact diagonalization in these optimal cases, but systematically overestimates it otherwise. Flat bands with identical quantum geometry tensors can exhibit substantial differences in stiffness. The stiffness of condensates formed between moiré flat bands, which typically have strong variations in Berry curvature and quantum metric across their Brillouin zones, tends to be larger when the bands have non-zero Chern numbers and can be larger than that of Landau levels. Our results reveal a behavior that is richer than that suggested by simple geometric bounds and provide new guiding principles for the design of robust flat-band condensates with large superfluid stiffness.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Thermodynamic learning
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-09-07 20:00 EDT
F. Corberi, S. dello Russo, G. Messuti, S. Scarpetta, L. Smaldone
We discuss the possibility to train a thermodynamic system, whose micro-variables are fully determined through the Hamiltonian by the usual statistical mechanical rules, to perform tasks such as memorization and generalization. Training is achieved by the application of suitable external fields, playing the role of {\it data}. At variance with conventional machine learning, no other logical or algorithmic rules are introduced. The system is amenable, in principle, to exact analytical calculations. We specialize this general approach to a prototypical Ising system with annealed dichotomous couplings and study its learning ability. Results indicate excellent memorization and good generalization capacity already for small systems, and a tendency to improve with system size.
Statistical Mechanics (cond-mat.stat-mech), Disordered Systems and Neural Networks (cond-mat.dis-nn)
6 pages, 3 figures, Supplemental Material available as an ancillary file on arXiv
Orientation selection and superconducting properties of epitaxial Al on ferromagnetic semiconductor (In,Fe)As
New Submission | Superconductivity (cond-mat.supr-con) | 2026-09-07 20:00 EDT
Hirotaka Hara, Keita Ishihara, Masaaki Tanaka, Le Duc Anh
Superconductor/ferromagnet heterostructures provide a versatile platform for exploring spin-dependent superconducting phenomena arising from interfacial proximity effects. In this article, we investigate the structural and superconducting properties of Al thin films grown in situ by molecular beam epitaxy on strained Fe-doped ferromagnetic semiconductor (FMS) (In,Fe)As layers. X-ray diffraction and transmission electron microscopy reveal the epitaxial growth of single-crystalline Al layers, with the growth orientation changing from (110) to (111) as the in-plane lattice constant of (In,Fe)As increases. The superconducting critical temperature of Al varies systematically with the film surface morphology and grain size. In addition, the critical magnetic field of Al exhibits an anomalous decrease below 0.5 K, possibly reflecting magnetic coupling to the underlying FMS (In,Fe)As layer. These findings provide a guideline for material design of epitaxial Al/(In,Fe)As heterostructures, which may serve as a promising platform for investigating proximity-induced superconducting and magnetic phenomena in semiconductor-based hybrid quantum devices.
Superconductivity (cond-mat.supr-con)
Field-Driven Coupled Magnon–Phonon–Electron Relaxation in Magnetite Using Steepest-Entropy-Ascent Quantum Thermodynamic Formalism
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-07 20:00 EDT
Deepak Dhariwal, William T. Reynolds Jr., Michael R. von Spakovsky
A field-driven steepest-entropy-ascent quantum thermodynamic (SEAQT) formulation is developed for longitudinal nonequilibrium relaxation in magnetite (Fe$ _3$ O$ _4$ ) with coupled electron, phonon, and magnon populations. Material-specific excitation spectra define the thermodynamic state space, while one relaxation parameter for each population sets its kinetic scale. A longitudinal magnetic field shifts the dressed magnon eigenenergies while the occupation basis remains fixed; irreversible redistribution conserves instantaneous energy and electron number while allowing the magnon population to vary. The formulation yields nonequilibrium subsystem temperatures, entropy production, magnetic-work identities, and a coupled small-signal susceptibility incorporating energy-conservation feedback among all three populations; the one-pole Debye response appears only as a limiting case. Numerical results under sinusoidal driving show a transition from nearly quasistatic behavior to frequency-dependent lag, finite-amplitude departure from the linear-response ellipse, and increasing higher-harmonic content. Relaxational work per cycle increases strongly with field amplitude and frequency, while the complex susceptibility is broader and shifted relative to a Debye reference. Entropy production remains positive, and the electron, phonon, and magnon temperatures show distinct excursions followed by secular heating when positive magnetic work is retained without heat rejection. The calculated work represents longitudinal magnon quasiparticle relaxation in a homogeneous single-domain model, not the total core loss of a finite ferrite specimen.
Materials Science (cond-mat.mtrl-sci)
Challenges in orbital current-driven domain wall motion in light metal/ferrimagnet heterostructures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-07 20:00 EDT
Min-Gu Kang, Jaerin Kim, Benjamin J. Jacot, Laura Van Schie, Pietro Gambardella
Recent advances in spintronics suggest that orbital Hall currents generated by charge injection in light metals can provide nonequilibrium angular momentum without relying on strong spin-orbit coupling (SOC). Here, we examine whether such orbital currents can drive domain wall (DW) motion in an amorphous ferrimagnetic alloy, Gd$ _{25}$ (Fe$ _{9}$ Co$ _{1}$ )$ _{75}$ (GFC), where the rare-earth sublattice offers strong SOC for orbital-to-spin conversion. We compare three representative heterostructures: Pt/GFC as a spin Hall reference, light-metal (Mn or Ti)/GFC for direct orbital-current injection, and light-metal/Pt/GFC incorporating an ultrathin Pt layer for orbital-to-spin conversion. Whereas Pt/GFC exhibits robust and reproducible spin-orbit-torque-driven DW motion, no current-driven DW motion is detected in Mn/GFC or Ti/GFC. Second-harmonic Hall measurements nevertheless reveal finite damping-like torques in both Mn/GFC and Ti/GFC, demonstrating that angular-momentum transfer into GFC does occur but is far weaker than in Pt/GFC. Inserting a 1-nm-thick Pt conversion layer strongly enhances the damping-like torque and restores DW motion. Thickness-dependent analysis further shows that DW mobility and depinning thresholds correlate with the interfacial Dzyaloshinskii-Moriya interaction and domain-wall width, highlighting weak torque conversion and insufficient interfacial stabilization of chiral DWs as key challenges for orbital-driven DW motion in light-metal/ferrimagnet heterostructures.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
24 pages, 6 figures. Published in Journal of Applied Physics
Journal of Applied Physics 140, 093902 (2026)
Spin-Charge Subordination in the Infinite-$U$ $SU(N)$ Hubbard Chain
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-09-07 20:00 EDT
Cătălin Paşcu Moca, Ovidiu I. Pâţu, Gergely Zaránd, Balázs Dóra
We obtain the exact full counting statistics of charge and flavor transport in the one-dimensional infinite-$ U$ $ SU(N)$ Hubbard model. The no-passing constraint freezes the ordered flavor sequence while the particle coordinates evolve as free spinless fermions. Consequently, charge transfer is governed by a free-fermion determinant, whereas flavor transfer is exactly subordinated to the number of particles crossing the observation cut. For an arbitrary traceless Cartan generator this yields an exact relation between the charge and flavor cumulants. The complete asymptotic flavor distribution is a universal non-Gaussian M-Wright law. Together, these results establish spin–charge subordination as a kinematic mechanism for anomalously slow internal-state transport in one-dimensional impenetrable quantum gases.
Quantum Gases (cond-mat.quant-gas), Statistical Mechanics (cond-mat.stat-mech)
5 pages, 3 figures
On the Stability of the Polar Phase of Superfluid 3He in Nematic Aerogels
New Submission | Superconductivity (cond-mat.supr-con) | 2026-09-07 20:00 EDT
We study the stability of the solution corresponding to the polar phase of superfluid 3He in nematic aerogels with respect to perturbations induced by magnetic impurity scattering. We show that when the perturbation simultaneously breaks axial and time-reversal symmetry, the polar-distorted A phase is realized with the highest transition temperature. Within the proposed model of a p-wave scattering potential, which accounts for the effective spin-orbit interaction between the orbital angular momentum of a scattering quasiparticle and the magnetic moment texture of the scatterer, we solve the eigenvalue and eigenvector problem for the Gor’kov self-consistency equation. Finally, we discuss how our results relate to the available experimental data.
Superconductivity (cond-mat.supr-con), Disordered Systems and Neural Networks (cond-mat.dis-nn), Other Condensed Matter (cond-mat.other)
10 pages, 1 Appendix, accepted for publication in JETP Letters
Multi-task deep-learning optimization of trade-off properties for superior-performance Fe-based soft magnetic alloys
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-07 20:00 EDT
Kang-Yuan Li, Mao-Zhi Li, Wei-Hua Wang
Fe-based amorphous alloys are promising soft magnetic materials for developing next-generation devices with high frequency and efficiency. However, optimization of Fe-based alloys with ultra-high saturation magnetic flux density (B_s), ultra-low coercivity (H_c), and good glass-forming ability is a notorious problem, owing to the vast composition space and complex trade-offs of these properties. Thus, conventional design methods encounter great challenges. Here we develop a generative multi-task deep learning (GMTDL) to achieve simultaneous optimization of compositions and trade-off properties. The GMTDL can sufficiently exploit and share the knowledge of datasets across different tasks, despite the limitation and imbalance of these datasets. Therefore, it exhibits superior performance in prediction of alloys with multiple targeted properties, outperforming previous machine learning-based design strategies. Moreover, the GMTDL can also tailor compositions, providing an efficient way to regulate properties and generate desired candidates for further experimental processing. The validity and reliability of GMTDL are rigorously tested by benchmarking with Fe-based alloys reported very recently. Moreover, some new alloys with ultra-high B_s and ultra-low H_c are predicted. The optimal content windows of key elements and their synergistic effects are also unraveled for practical guidance. Thus, our study establishes an effective and reliable paradigm for simultaneous prediction and optimization of high-performance materials with multiple properties.
Materials Science (cond-mat.mtrl-sci)
92 pages, 8 main-text figures, 1 main-text table; Supplementary Materials included
Chin. Phys. B, 2026, 35(7): 070705
Excitation caging in a vertex-frustrated quasiperiodic Einstein artificial spin ice
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-09-07 20:00 EDT
T. Wang, F. Museur, G. M. Macauley, J. Colbois, L. Berchialla, F. Flicker, P. M. Derlet, L. J. Heyderman
Naturally occurring bulk quasicrystals are rare, and magnetic instances are rarer still, with chemical constraints typically permitting the synthesis of approximants rather than true quasicrystalline magnets. Here, we present an artificial spin ice based on a recently discovered Einstein lattice, the Hat tiling, which is built from the first known shape - the hat - that tiles the plane only aperiodically. The Einstein artificial spin ice has long-range structural order with no translational symmetry, and low-connectivity vertices with well-defined local ground states and excitations. Together, these properties provide a model two-dimensional quasicrystalline magnet, with magnetic correlations that we probe with magnetic force microscopy and parallel-tempered Monte Carlo simulations. We identify a two-stage partial ordering process, driven by the competition between two possible positions for magnetic excitations. This competition is resolved in the ground-state manifold, where exactly one magnetic excitation is caged on each antihat, yet the manifold remains macroscopically degenerate. This yields an unusual type of medium-range order, where the underlying quasiperiodic long-range order is randomly modulated by a strictly constrained disorder. Our findings establish the Einstein artificial spin ice as a blueprint for understanding quasicrystalline magnetism, demonstrating how quasiperiodic monotile geometries can be exploited to engineer unconventional magnetic phases with no direct equivalent in periodic systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Statistical Mechanics (cond-mat.stat-mech)
Main text 8 pages and 4 figures, Methods 3 pages, Supplementary material 10 pages
The elasticity of semiflexible polymers with reversible spontaneous curvature in two dimensions
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-09-07 20:00 EDT
Donghyeon Kim, Panayotis Benetatos
Many semiflexible filaments exhibit structural asymmetries that lead to a curved ground state (curvature in the absence of thermal fluctuations, external forces, or torques). This property is known as spontaneous curvature. Many semiflexible polymers can reversibly develop spontaneous curvature through internal conformational transitions or through transient interactions with their molecular environment. In this article, we show that such reversible spontaneous curvature, even in the absence of transitions in the value of the bending stiffness, provides a minimal mechanism for ensemble-dependent elasticity. We formulate an analytically tractable two-state modified wormlike-chain model in two dimensions, in which an uncurved state (without spontaneous curvature) competes with a curved state (possessing spontaneous curvature). The transition is controlled by an activation energy. Within the weak-bending approximation, we obtain the Gibbs and Helmholtz partition functions for a stretched filament with reversible constant (uniform along the backbone) or sinusoidal spontaneous curvature and for a grafted bistable filament driven either by an end torque or a bending force. Stretching or bending induces a crossover from spontaneous-curvature-dominated to entropic elasticity. We show how the elastic response differs in the two ensembles (Gibbs vs Helmholtz). In addition, we consider the case where the curved state is also characterized by a higher value of the bending stiffness. In that case, a reentrant transition is possible as we stretch the bistable filament.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
19 pages, 20 figures
J. Chem. Phys. 165, 064111 (2026)
Spin-Point-Group Classification of Multipoles for Nonrelativistic Collinear Magnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-09-07 20:00 EDT
Multipole moments provide a unified symmetry language for describing electronic degrees of freedom and their associated physical responses. Although active multipoles have been systematically classified for crystallographic and magnetic point groups, their classification in spin point groups, which naturally describe magnetic systems in the absence of spin-orbit coupling, has remained unexplored. In this work, we present a complete classification of active orbital and spin multipoles for all 32 nonmagnetic and 122 collinear spin point groups. Treating orbital and spin degrees of freedom independently, we identify the symmetry-allowed multipoles associated with nonmagnetic and collinear magnetic orderings and clarify their hierarchy through comparisons among the corresponding spin point groups. The resulting classification provides a symmetry-based database that distinguishes structural and magnetic contributions to active multipoles and directly identifies microscopic order parameters, including those responsible for $ d$ -, $ g$ -, and $ i$ -wave altermagnetism. Furthermore, by classifying response tensors within the same framework, we establish a correspondence between active multipoles and symmetry-allowed physical responses. This correspondence systematically distinguishes nonrelativistic responses that survive without spin-orbit coupling from those requiring relativistic effects, providing a unified framework for understanding and predicting spin-dependent electromagnetic and transport phenomena in magnetic materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
200 pages, 1 figure, 173 tables
Liquid-liquid phase separation precedes crystallization in supercooled water-glycerol solutions
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-09-07 20:00 EDT
Iason Andronis, Sharon Berkowicz, Mariia Filianina, Maddalena Bin, Robin Tyburski, Robert Bauer, Yuriy Chushkin, Federico Zontone, Michael Sprung, Wojciech Roseker, Fabian Westermeier, Felix Lehmkühler, Fivos Perakis
Understanding the structural evolution of supercooled water-glycerol solutions is important for cryopreservation, yet distinguishing liquid-state transformations from ice crystallization remains challenging. Here, we investigate a deeply supercooled water-glycerol solution by X-ray photon correlation spectroscopy (XPCS) in ultra-small-angle X-ray scattering (USAXS) geometry, combined with wide-angle X-ray scattering (WAXS). This combination simultaneously captures the structural and dynamical evolution of the supercooled liquid upon quenching to cryogenic temperatures (172 K). We observe discontinuous changes in the liquid structure on molecular length scales and formation of microscale domains. The dynamics slow down during this stage and exhibit hyper-diffusive, ballistic-like relaxation. This transformation precedes ice crystallization, which we identify from the emergence of ice Bragg peaks in WAXS, allowing the two processes to be temporally separated. Phase-field (Cahn-Hilliard) simulations qualitatively reproduce the experimental observations and show that a spinodal-decomposition scenario is consistent with the measured scattering evolution. These findings are consistent with a liquid-liquid phase separation scenario preceding ice crystallization and provide a route to disentangle the two processes in supercooled aqueous systems.
Soft Condensed Matter (cond-mat.soft), Chemical Physics (physics.chem-ph)
Submitted to The Journal of Chemical Physics
Cascade spin dynamics of excitons localized in indirect-band-gap (In,Al)As/AlAs quantum dots with type-I band alignment
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-09-07 20:00 EDT
S. V. Nekrasov, I. V. Kalitukha, A. A. Golovatenko, Ya. A. Kuznetsova, N. O. Mikhailenko, M. D. Ragoza, T. S. Shamirzaev, Yu. G. Kusrayev
We investigate the spin dynamics of excitons localized in type I (In,Al)As/AlAs quantum dots with an indirect in momentum space band structure. Polarized selective photoluminescence spectroscopy, i.e. fluorescence line narrowing, under magnetic fields up to 5 T applied in the Faraday geometry is employed. The experiment reveals a cascade spin evolution process of excitons in the indirect band-gap quantum dots: an initial short term spin dynamics associated with excited direct exciton states possessing a large oscillator strength is followed by electron relaxation into the X valley of the Brillouin zone and subsequent long term spin dynamics of indirect excitons. The two step mechanism manifests itself in the distinct features of the magnetic field dependences of photoluminescence: two component recovery of optical orientation, two component linear to circular polarization conversion and the presence of the linear polarization plane rotation. At the same time, suppression of the optical alignment shows one-component behavior governed by the spin dynamics of the indirect exciton states. Within the pseudospin formalism, we derive analytical expressions that quantitatively describe the observed dependences and yield estimates for the anisotropic exchange splitting: 210 {\mu}eV for direct excitons and 1.3 {\mu}eV for indirect excitons. Further analysis using the density matrix formalism agrees well with the pseudospin model calculations and shows that the finite optical orientation at zero magnetic field is due to comparable magnitudes of the anisotropic splitting of the indirect exciton states and the splitting of the X-valley electron states caused by the hyperfine interaction with nuclei.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Nonreciprocal plasmonic response of drift-biased two-dimensional metals
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-09-07 20:00 EDT
Gonzalo Álvarez-Pérez, Joel D. Cox
We develop a nonlocal electrodynamic framework for drift-biased two-dimensional electron gases (2DEGs) with Dirac (linear) and parabolic (quadratic) dispersions, deriving closed-form drift-dependent conductivity tensors from the Boltzmann transport equation. We obtain the plasmon dispersion and near-field emission of a point dipole, revealing nonreciprocal propagation in both systems. At equal drift parameter, the parabolic 2DEG exhibits stronger nonreciprocity than the Dirac system, although we find that a larger drift parameter does not by itself produce stronger nonreciprocity: the response is set by the interplay of drift and plasmon nonlocality. As such, the combination of strong nonlocality and experimentally accessible drift velocities of semiconductor 2DEGs identifies parabolic systems as a promising platform for tunable, nonreciprocal plasmonics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Optics (physics.optics)
Nuclear quantum effects in the thermal conductivity of solid hydrogen
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-07 20:00 EDT
Hengtai Zheng, Zezhu Zeng, David E. Manolopoulos
We use a combination of path integral and lattice dynamics methods to calculate the thermal conductivity of solid parahydrogen. Path integral molecular dynamics is first used to calculate a centroid potential of mean force at each temperature, on which a harmonic phonon basis is constructed using the finite displacement method. We then calculate anharmonic force constants on the centroid potential and solve the linearised phonon Boltzmann transport equation for the thermal conductivity. The resulting renormalised phonon dispersion curves, heat capacity, and thermal conductivity are all in remarkably good agreement with experimental measurements. We find that the heat transport is dominated by collective relaxon modes at low temperatures and cannot be captured by making the phonon relaxation time approximation. Indeed, quantitative agreement with the experimental thermal conductivity is only achieved when the nuclear quantum effects in the centroid potential of mean force, phonon boundary scattering, and hydrodynamic transport are all explicitly considered. This is also likely to be the case for other quantum crystals.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph), Computational Physics (physics.comp-ph)
11 pages, 5 figures
Universal Thermodynamic Law Governing Stochastic Pendulum Clocks
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-09-07 20:00 EDT
Clocks’ performance, especially their precision, is fundamentally limited by thermodynamic laws as they are physical devices. Yet, it is known that the established thermodynamic uncertainty relation (TUR), which imposes an upper bound on the uncertainty product of the precision of oscillations and entropy production, is violated for underdamped systems such as stochastic pendulum clocks. Here, we show that for a general class of stochastic pendulum clocks described as a weakly nonlinear oscillator the uncertainty product of the phase of a pendulum clock and entropy production takes a universal and simple form that depends solely on the degree of nonlinearity. Its validity and limitations are examined using several representative models of pendulum clocks. Our framework reveals a universal thermodynamic principle governing stochastic pendulum clocks beyond the conventional TUR and provides a foundation for designing optimal pendulum clocks that operate efficiently in stochastic environments.
Statistical Mechanics (cond-mat.stat-mech)
9 pages, 4 figures
Bias-field control of the Neel skyrmion nonlinearity in a confined nanostructure
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-09-07 20:00 EDT
A.V. Valkov, A.A. Matveev, O.Yu. Arkhipova, R.V. Shcherbakov, A.R. Safin, S.A. Nikitov
We study the nonlinear dynamics of a cylindrical skyrmion-based oscillator within the framework of a generalized Thiele model. We demonstrate the influence of an bias magnetic field applied perpendicular to the plane of the nanocylinder on the oscillation frequency and on the nonlinearity coefficient. It is shown that the field tunes the response frequency, while also producing a substantial change in the nonlinear frequency shift. We find that the nonlinearity coefficient reverses its sign as the field crosses a certain critical value. The variation of the nonlinearity coefficient with the field is clearly illustrated by the observed qualitative changes in nonlinear amplitude-frequency responses. Controlling the nonlinear properties of a skyrmion oscillator by changing the bias magnetic field opens up prospects for creating tunable computational elements for neuromorphic applications.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Anomalous diffusion in porous fractal media
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-09-07 20:00 EDT
Alexander Iomin, Trifce Sandev
We suggest a model of a diffusive process inside a fractal sponge structure, which is a generalization of the diffusion processes on a comb and fractal mesh structure. The sponge model is considered as the direct product of Cantor sets. It is shown that the corresponding one-dimensional diffusion process is governed by a generalized Fokker-Planck equation with a power-law memory kernel and a position-dependent diffusion coefficient. That is, the fractal structure of the medium induces memory effects and heterogeneity in the transport system. The considered model may be of interest to describe anomalous heat transport in porous fractal media.
Statistical Mechanics (cond-mat.stat-mech)
Local coordination, structural softening, and polarization-switching energetics in Sc-alloyed GaN
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-07 20:00 EDT
Shailesh Kalal, Gueorgui Kostov Gueorguiev, Martin Magnuson, Edward Ferraz de Almeida Junior, Rohini Sanikop, Sagar Jathar, Per Sandström, Ray-Hua Horng, Jens Birch, Per Eklund, Ching-Lien Hsiao
Sc-alloyed wurtzite nitrides exhibit strongly tunable electromechanical and ferroelectric properties, yet the relationship between their lattice evolution and local bonding environment remains insufficiently established, particularly in Sc$ _x$ Ga$ _{1-x}$ N. Here, we investigate the structural and local bonding evolution of Sc$ _x$ Ga$ _{1-x}$ N across the dilute-to-intermediate composition range by combining X-ray diffraction, Sc K-edge X-ray absorption near edge structure (XANES), extended X-ray absorption fine structure (EXAFS) and first-principles calculations. Sc incorporation produces an anisotropic lattice expansion and a progressive reduction in the c/a ratio. XANES and EXAFS reveal a concurrent modification of the local environment around Sc, with the effective Sc-N coordination number increasing from 4.1(4) to 4.5(2) and the average Sc-N bond length increasing from 2.045(7) to 2.081(8)Å over x=0.06-0.26. The local response is accompanied by a reduction in the Sc K-edge pre-edge intensity, consistent with a gradual reduction of the local tetrahedral asymmetry. First-principles calculations show that these structural changes are associated with site-selective distortions around Sc and progressive flattening of the structural energy landscape. The calculated intrinsic polarization-switching barrier decreases from 24.2 to 19.0 meV/Å$ ^3$ with increasing Sc content, while the calculated piezoelectric stress coefficient (e$ _{33}$ ) increases from 0.82 to 1.66C/m$ ^2$ and elastic constant (C$ _{33}$ ) decreases from 380 to 227GPa, resulting in an increase of piezoelectric strain coefficient (d$ _{33}$ ) from 2.99 to 12.46~pC/N. These results show that Sc incorporation progressively modifies the local coordination environment and structural energetics of ScGaN while the long-range wurtzite structure remains preserved over the investigated composition range.
Materials Science (cond-mat.mtrl-sci)
13 pages, 4 figures
ANT:UI: An interactive 3D tool for preparing ANT.Gaussian molecular junction geometries
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-09-07 20:00 EDT
A. Martinez-Garcia, J. J. Palacios, C. Sabater
this http URL is a Python graphical interface that automates the construction of molecular-junction geometries for NEGF-DFT quantum transport calculations. Through a real-time 3D viewer, users interactively position electrodes and molecules and generate complete, ready-to-run input files for Gaussian and this http URL without manual scripting. Dedicated Pull, Grid, and Rotation assistants further automate electrode-pulling sequences, surface scans, and step-wise rotation studies, with optional geometry-optimisation chaining across each sequence. By replacing a process that previously demanded days of custom scripting with a point-and-click workflow, this http URL accelerates research in theoretical molecular electronics and lowers the barrier to entry for new users. The software also exports all constructed geometries in standard XYZ format, allowing direct reuse in molecular dynamics codes or third-party visualization tools without manual reformatting.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Tensor-Network Inference in a Field-Coupled XY Model for Portfolio Allocation
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-09-07 20:00 EDT
Kartikeya Chowdhry, G Subrahmanya V.R.K. Rao
We apply tensor-network methods to a field-coupled XY model for long-only portfolio construction. Daily return statistics set asset-specific fields and correlation couplings. Correlation distance, four-point Gromov hyperbolicity, and Ward clustering are used to construct a sparse interaction path. A Fourier-Bessel expansion maps the continuous angular partition function to a finite-current tensor network; bottom-up and top-down contractions then give the one-site marginals and equilibrium cosine scores. A softmax map converts these scores into positive, fully invested portfolio weights. We study five equity markets over continuous ranges of inverse temperature beta and concentration gamma, and compare selected parameter pairs with long-only Markowitz frontiers and standard benchmarks. The same-sample comparisons demonstrate a tractable route from financial time series to network-adjusted allocations; predictive trading performance is outside their scope.
Statistical Mechanics (cond-mat.stat-mech)
52 pages, 10 figures, 5 tables
Influence of dislocation density on the tribological response in oxides: case study on SrTiO3
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-07 20:00 EDT
Chukwudalu Okafor, Oliver Preuß, Thomas Chudoba, Ujjval Bansal, Daniela Exner, Konrad Priszokovich, Yanfei Gao, Christoph Kirchlechner, Xufei Fang
Most ceramics suffer from brittle surface damage and cracking when small particles slide across the surface under low load. Microscratching tests are a useful technique to mimic this loading scenario while retaining the material’s deformation history; however, the impact of pre-seeded dislocations, which can significantly facilitate plastic deformation, has not been explored in ceramics. Here, the influence of mechanically seeded dislocations on the microscratching response of oxides is investigated using a model perovskite, SrTiO3. First, various dislocation densities over four orders of magnitude are introduced via room-temperature cyclic Brinell indenter scratching. Subsequently, load-ramped microscratching tests are performed within the pristine and dislocation-seeded regions using a nominally 30 {\mu}m spherical diamond tip. On the reference pristine surface, we observe a clear transition from elastic to elasto-plastic deformation, followed by median/radial cracking at higher loads. In contrast, pre-seeded dislocations, accompanied by residual compressive stresses, suppress elastic deformation and lead to median/radial crack shortening and subsequent transition to a partial cone crack. The subsurface cracks are characterized by 3D Nano-CT. The changes in crack geometry, with and without dislocations, were described using the Lawn-Evans-Marshall and Lawn-Wiederhorn-Roberts models. These findings provide direct evidence of dislocation-regulated near-surface damage tolerance, with general applicability to other plastically deformable oxides.
Materials Science (cond-mat.mtrl-sci)
23 pages, 9 figures
Generalized Helicity-Dependent Magnetization Switching via Substrate Phonons
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-07 20:00 EDT
F.G.N. Fennema, H. Damas, H. Yoshikawa, A. Tsukamoto, C.S. Davies, A. Kirilyuk
Coherent excitation of circularly-polarized substrate phonons can drive deterministic reversal of magnetization in an adjacent magnetic layer. However, the extent to which this substrate-mediated mechanism can be generalized across different materials remains unresolved. Here, we measure and compare the spectral dependence of helicity-dependent magnetization reversal in magnetic GdFeCo layers grown on a diverse set of diamagnetic substrates. Switching is observed for all investigated substrates, spanning six point groups and several infrared-active transverse-optical phonon symmetries. While the switching spectra broadly overlap with the Reststrahlen bands, their maxima are systematically shifted to wavelengths shorter than the corresponding transverse-optical phonon resonances. This spectral mismatch shows that substrate absorption alone does not determine the switching efficiency. Transfer-matrix calculations show that strong absorption concentrates energy deposition near the substrate interface, providing a possible source of local heating that could suppress magnetization reversal. Our results reveal the broad applicability of substrate-mediated phononic switching while showing that its efficiency is governed by the full optical response of the heterostructure rather than substrate absorption alone.
Materials Science (cond-mat.mtrl-sci)
Engineering Giant Thermoelectric Performance through Electrode-Coupling Geometry and Magnetic Flux in Quasiperiodic Su-Schrieffer-Heeger Rings
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-09-07 20:00 EDT
Sridhar, Souvik Roy, Malay Bandyopadhyay
We investigate coherent thermoelectric transport in magnetic-flux-threaded quasiperiodic Su-Schrieffer-Heeger (SSH) rings with engineered multi-site electrode couplings using the nonequilibrium Green’s function formalism within the Landauer-Büttiker framework. We demonstrate that the electrode-coupling geometry serves as a powerful control parameter for tailoring quantum interference, thereby reshaping the transmission spectrum and thermoelectric response. In the absence of magnetic flux, the trivial dimerized phase ($ t_1>t_2$ ) exhibits the highest thermoelectric efficiency, with asymmetric coupling producing a substantially larger figure of merit than the symmetric geometry. Magnetic flux further reconstructs the transmission spectrum through Aharonov-Bohm interference, driving a crossover of the optimal thermoelectric regime from the trivial to the topological dimerized phase. Under optimal flux conditions, the thermoelectric figure of merit reaches $ ZT \approx 12$ for symmetric coupling and is dramatically enhanced to $ ZT \approx 90$ for asymmetric coupling through enhanced energy filtering and suppressed electronic thermal transport. We further establish a clear correlation between the enhancement of thermoelectric efficiency and the violation of the Wiedemann-Franz law. Our results demonstrate that the combined interplay of quasiperiodicity, topology, magnetic flux, and electrode-coupling geometry provides a versatile strategy for engineering high-performance coherent thermoelectric devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
16 Pages, 14 Figures; 2 Tables
A locally ab initio computational framework for arbitrary incommensurate materials interfaces
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-07 20:00 EDT
Drake Niedzielski, Tomás A. Arias
Incommensurate materials interfaces constitute a broad and technologically important class of systems, yet their lack of shared periodicity limits predictive and computationally efficient first-principles electronic-structure methods. Here we introduce a scalable computational framework for constructing locally ab initio electronic Hamiltonians for arbitrary materials interfaces. Our approach exploits the nearsightedness of Wannier Hamiltonian matrix elements, enabling their systematic extrapolation and interpolation across interlayer registries. This strategy yields transferable Hamiltonians that retain first-principles accuracy while bypassing the need for prohibitively large commensurate supercells or Moiré approximations. We validate the framework on quasicrystalline 30° twisted bilayer graphene, reproducing experimentally observed spectral features including mirrored Dirac cones and minigaps at avoided crossings arising from generalized interlayer scattering. We further predict quasiperiodic flat-band states in experimentally accessible doping regimes. By enabling predictive electronic-structure calculations across structurally incommensurate interfaces, this framework establishes a practical route to first-principles exploration of emergent interfacial phenomena.
Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
Cross-Layer Anomalous Hall Transport driven by Néel-Vector rotating in the Altermagnet candidate V2Te2O
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-07 20:00 EDT
Yanan Pan, W. Z. Zhuo, Pan Gao, Ziyu Zhou, Junqing Xu, Lijie Shao, Damin Meng, Weiwei Chen, Zhongjun Li, Ye Yang
In van der Waals (vdW) materials, weak interlayer coupling generally suppresses vertical dispersion, reinforcing the conventional paradigm that in-plane transport dominates over cross-layer channels. Here, using first-principles calculations and magnetic symmetry analyses, we uncover a giant, symmetry-unlocked cross-layer anomalous Hall conductivity (AHC) in the vdW altermagnet V2Te2O. In the magnetic ground state with Neel vector N//z, horizontal mirror symmetry protects a spin-polarized nodal chain near the Fermi level and strictly enforces zero anomalous Hall response. Tilting the Neel vector explicitly breaks this mirror protection, allowing spin-orbit coupling to gap the nodal chain and activate a sharp cross-layer Hall response. When the Neel vector is rotated into the in-plane configuration (N//x), cross-layer orbital hybridization generates intensive Berry curvature hotspots, boosting the cross-layer component of AHC {\sigma}{yz} to approximately 255 S/cm, which exceeds in-plane component {\sigma}{xy} by nearly two orders of magnitude. Furthermore, varying the azimuthal angle systematically redistributes the anomalous Hall response, enabling full directional control of transverse transport. Our findings demonstrate a highly sensitive cross-layer anomalous Hall switch activated by low-barrier spin canting, offering promising avenues for directional tensor selection and low-power multi-axial vdW spintronics.
Materials Science (cond-mat.mtrl-sci)
Symmetry-protected triplet Weyl complexes
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-07 20:00 EDT
Yun-Yun Bai, Ke-Xin Pang, Yan Gao, Weikang Wu, Shengyuan A. Yang
The Nielsen-Ninomiya theorem dictates that Weyl nodes must appear in pairs of opposite chirality to preserve global charge neutrality. However, in crystals, specific crystalline symmetries can stabilize multi-Weyl nodes, circumventing this pairwise constraint and enabling compensated Weyl complexes with mixed chiral charges. The minimal configuration of this type is a triplet Weyl complex (TWC), comprising exactly three Weyl nodes. Here, we systematically investigate the symmetry conditions required to realize TWCs. By screening all 1651 magnetic space groups (MSGs) in both spinless and spinful systems, we establish that: (i) Only TWCs with charge magnitudes of $ {1,1,2}$ and $ {1,2,3}$ are permitted; (ii) the $ {1,1,2}$ configuration can be realized in 166 spinless MSGs and 70 spinful MSGs; and (iii) the $ {1,2,3}$ -TWCs, which has not been reported before, can occur in 10 MSGs for both spinless and spinful cases. We explicitly demonstrate the existence of $ {1,2,3}$ -TWC in a tight-binding model. Furthermore, we present the first electronic realization of $ {1,1,2}$ -TWC topological semimetal state in the chiral carbon allotrope DZQH-C$ _{36}$ , in which the three Weyl nodes form a collinear configuration, leading to a characteristic ``S’’-shaped surface Fermi arc pattern. Our findings uncover novel topological states featuring mixed chiral charges and provide guidance for exploring their physics in concrete material systems.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
5 figures
On the growth of operator entanglement in brickwork circuits with Yang–Baxter gates
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-09-07 20:00 EDT
We study the operator entanglement of local operators in one-dimensional brickwork circuits whose two-site gate satisfies the braid relation; throughout this work, we call such a gate a Yang–Baxter gate. We establish upper bounds for several structured, overlapping classes of Yang–Baxter gates. We show that the operator Schmidt rank remains uniformly bounded in time for all qubit Yang–Baxter gates and, in arbitrary local dimension, for permutation gates obtained from non-degenerate Yang–Baxter maps. We also show that it grows at most polynomially for involutive dual-unitary Yang–Baxter gates and for arbitrary phase dressings of permutation gates obtained from non-degenerate Yang–Baxter maps. These results imply, respectively, constant and logarithmic upper bounds on the operator entanglement. Conversely, we construct a seven-state involutive Yang–Baxter gate without dual unitarity and a one-site operator whose exact operator Schmidt rank grows exponentially, although the corresponding operator entropies remain undetermined. Entanglement growth in the general Yang–Baxter case remains open. All proofs and selected examples were constructed by ChatGPT 5.6 Sol.
Statistical Mechanics (cond-mat.stat-mech), Exactly Solvable and Integrable Systems (nlin.SI), Quantum Physics (quant-ph)
67 pages
Anharmonic Lattice Dynamics and Anisotropic Electron-Phonon Coupling in Quasi-1-Dimensional Charge Density Wave Ta2NiSe7
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-07 20:00 EDT
Prithwija Mandal, S. Nanthini, Aditya Singh, Kewal S. Rana, Dibyendu Dey, Kanishka Biswas, Ajay Soni
The microscopic origin of charge density wave formation in quasi one dimensional Ta2NiSe7 remains actively debated, particularly regarding the relative contributions of Fermi surface nesting, electron phonon coupling, and lattice instabilities. Here, we combine temperature and orientation dependent polarized Raman spectroscopy with first principles calculations to uncover the anisotropic electronic and lattice interactions governing the CDW state in Ta2NiSe7. Heat capacity and electrical transport measurements identify an incommensurate CDW transition at 61 K. Raman spectroscopy reveals pronounced in plane anisotropy, with e ph coupling strength along intrachain b axis exceeding five times that along interchain c axis, whereas lattice anharmonicity is enhanced by threefold along c axis. First principles calculations identify Ta2 Se octahedral vibrations and Ta Se electronic states near the Fermi level as dominant channels mediating the anisotropic e ph interaction. Exceptionally strong and directional e ph coupling along b axis establishes lattice driven electronic instability as the primary mechanism underlying CDW modulation and highlights the dominance of intrachain interactions in strongly coupled Ta2NiSe7. Despite this strong coupling, the CDW remains incommensurate, indicating that lattice anharmonicity provides an additional degree of freedom. Enhanced anharmonicity along c axis suggests that anisotropic phonon phonon interactions reshape the free energy landscape and contribute to stabilizing incommensurate phase. These findings reveal a cooperative interplay between anisotropic e ph coupling and lattice anharmonicity in governing CDW formation in low dimensional quantum materials.
Materials Science (cond-mat.mtrl-sci)
23 pages, 7 figures
Semiclassical thermoelectric transport in disordered Dirac electron system Ag2Te
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-07 20:00 EDT
Kentaro Kuga, Keisuke Hirata, Daiki Goto, Ryogo Ishihara, Masaharu Matsunami, Tsunehiro Takeuchi
We investigated the thermoelectric effects of the Dirac electron system Ag2Te under magnetic field. Our anal-ysis based on the Boltzmann semiclassical model associated the disorder with the unconventional magnetic field responses such as linear magnetoresistance, linear Nernst effect, step-like Nernst effect, and sign change in Nernst effect. The analysis also revealed the impurity band near the Fermi energy. We simultaneously clari-fied the serious impact of the thermal Hall effect on the measurement of the Nernst effect, and we proposed the definitive solution. Our careful measurement and analysis will be the standard for the thermoelectric study under magnetic field.
Materials Science (cond-mat.mtrl-sci)
Phys. Rev. B 114, 154203 (2026)
Environment-assisted transport in a strongly correlated boundary-driven Fermi-Hubbard chain
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-09-07 20:00 EDT
We study steady-state transport in a one-dimensional Fermi-Hubbard chain coupled to particle reservoirs at the boundaries and to local dephasing baths at each site, using the time-evolving block decimation (TEBD) method to solve the Lindblad master equation. In the absence of dephasing, the current exhibits two well-separated maxima as a function of the boundary driving rate, reflecting the distinct charge and spin energy scales of the strongly correlated regime. Upon introducing dephasing, we find two distinct dephasing-induced transport-enhancement regimes, in contrast to the single enhancement previously reported for spinless fermions. Analysis of the non-equilibrium steady state in the Hamiltonian eigenbasis reveals that the two regimes originate from distinct dephasing-induced redistribution processes: the first involves redistribution within the uppermost Hubbard band, while the second involves transitions between Hubbard bands. Our results demonstrate how many-body correlations shape the interplay between coherent driving, dephasing, and quantum Zeno physics in strongly correlated open systems.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
23 pages, 7 figures
Interfacial Accommodation as a Candidate Ductility Pathway in Intermetallic-Rich Alloys
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-07 20:00 EDT
Heterophase interfaces are increasingly recognized as active participants in plastic deformation, yet quantitative methods for comparing their strain-accommodation capacity remain limited. Here, we present an atomistic framework for quantifying interface-mediated strain accommodation using molecular dynamics simulations. Interface broadening, roughening, and migration are extracted from atomistic trajectories and combined into an Interface Accommodation Index, with a normalized counterpart accounting for differences in initial interface structure. A weighting sensitivity analysis demonstrates that the relative ranking of interfaces is robust to the specific form of the index. The framework is demonstrated for three experimentally motivated interfaces, Al/Al3Ti, Al/Al9M2, and Al9M2/Al3Ti (M = Fe, Co, Ni), under tensile, compressive, and shear loading. Bulk simulations show that Shockley partial dislocations dominate plastic deformation, with alloy chemistry governing the transition toward mixed-character dislocation networks. Tensile loading produces the greatest interface accommodation, while shear produces comparatively limited structural evolution. The Al9M2/Al3Ti interface exhibits both the highest yield resistance and the largest accommodation response, suggesting that intermetallic-intermetallic interfaces can simultaneously sustain load and redistribute strain. These simulations quantify structural accommodation rather than ductility or fracture directly; their connection to macroscopic ductility therefore requires experimental validation. The framework provides a transferable approach for comparing interface accommodation in multiphase alloys and identifies interface chemistry and crystallography as important design variables for damage-tolerant structural materials.
Materials Science (cond-mat.mtrl-sci)
Glassy dynamics, crossover temperature and density scaling in fragile glass-formers
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-09-07 20:00 EDT
Ankit Singh, Vinay Vaibhav, Swarn Lata Singh, Yashwant Singh
We investigate the slowing down of dynamics in a glass-forming mixture interacting via an inverse-power-law (IPL) potential using a combination of theory and large-scale molecular dynamics simulations. We measure the static pair-correlation function, configurational entropy, inherent-structure energy, and structural relaxation time. We employ a theoretical framework to calculate the structural relaxation time $ \tau_{\alpha}$ , which is found to be in very good agreement with the simulation results. The theory identifies a local structural order which defines the cooperativity of the relaxation and brings forth a fluctuation induced parameter $ \psi ( T )$ and a crossover temperature $ T_a$ that characterize the density and temperature dependence of the glassy dynamics. Furthermore, we determine a crossover temperature using independent dynamical and thermodynamic criteria and compare with the theoretically predicted crossover temperature $ T_a$ . Relaxation dynamics is shown to obey density-temperature scaling, similar to thermodynamic properties, in terms of a variable $ \Gamma$ formed by an appropriate combination of density and temperature, characteristic of IPL interactions. Finally, we show that, when the excess thermodynamic and dynamic quantities obtained at different densities are plotted as functions of the reduced temperature $ T/T_a$ (or $ T_a/T$ ), the data collapse onto master curves with excellent agreement between theory and simulation. These scaling relations provide a unified description of the thermodynamics and dynamics in IPL systems, enabling the prediction of relaxation behavior over a wide range of densities from data at a single state point.
Soft Condensed Matter (cond-mat.soft), Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech)
13 pages, 17 figures
Neural-field design of broadband Rayleigh-wave carpet cloaks under microstructure realisability constraints
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-07 20:00 EDT
David Aznaurov, Davit Piliposyan, Danila Rukhovich, Sebastien Guenneau
Transformation elasticity provides appropriate material distributions for elastodynamic cloaks but the required stiffness tensors generally violate the minor symmetries of Cauchy elasticity and are difficult to realise using conventional materials. Existing approaches restore these symmetries by modifying the transformed tensor, producing only an approximate cloak. In this work rather than modifying the transformed tensor we seek the best performing cloak within the class of Cauchy materials. We formulate 2D Rayleigh wave carpet cloak design as an optimisation problem governed by partial differential equations. Using a coordinate based neural-field and a differentiable finite element model solver we optimise symmetric stiffness and density fields by minimising wave field distortion. Both single frequency and broadband optimisation are considered, with the broadband model trained over multiple frequencies. Physical realisability is addressed using a database of homogenised microstructures through conditional diffusion, neural-field inverse design, and nearest-neighbour selection. FEM simulations show that the optimised Cauchy design approaches the ideal transformation-based cloak. After projection onto explicit microstructures, the homogenised representation recovers approximately 97% of the defect free reference surface-displacement magnitude, while direct FEM simulation of the fully resolved microstructured geometry recovers approximately 76%
Materials Science (cond-mat.mtrl-sci)
Transparency-engineered SQUID cells for Kerr-free three-wave-mixing Josephson metamaterials
New Submission | Superconductivity (cond-mat.supr-con) | 2026-09-07 20:00 EDT
Claudio Guarcello, A. Mert Bozkurt, Carlo Barone, Giovanni Filatrella, Alessandro Bruno, Sergio Pagano
We introduce a transparency-engineered rf-SQUID cell for Kerr-free three-wave-mixing Josephson metamaterials. This design replaces the conventional tunnel-junction element with an effective Josephson element formed by two junctions in series, yielding a non-sinusoidal energy-phase relation that can be used as a tunable nonlinear design resource. We show that the asymmetry between the two series junctions and the applied flux bias provide independent control over the local expansion of the rf-SQUID potential, enabling operating points where the leading quartic Kerr term is suppressed while the cubic nonlinearity remains finite. We derive the corresponding Kerr-free condition, identify the resulting operating ridge in parameter space, and analyze the local stability and passive-matching constraints that bound its physically accessible portion. Our results provide a compact unit-cell design principle for three-wave-mixing Josephson metamaterials and suggest a route toward Kerr-suppressed Josephson traveling-wave parametric amplifiers.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
17 pages, 5 figures
Dipolar and quadrupolar spin supersolid states in a spin-1 triangular antiferromagnet
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-09-07 20:00 EDT
Yixuan Huang, Yuan Gao, Wei Li, Seiji Yunoki, Sadamichi Maekawa
We present a systematic numerical study of the spin-1 antiferromagnetic Heisenberg model on the triangular lattice in an out-of-plane magnetic field, using Density Matrix Renormalization Group (DMRG) methods. By mapping out the quantum phase diagram as a function of the single-ion anisotropy $ D_z$ and magnetic field, we identify distinct dipolar and quadrupolar spin supersolid states, characterized by spontaneous U(1) symmetry breaking with finite spin superfluid stiffness coexisting with longitudinal translational symmetry breaking. At zero field, the dipolar spin supersolid with a ‘Y’-type spin configuration persists down to $ D_z = 0$ , whereas the quadrupolar spin supersolid prevails at large $ D_z$ . At intermediate fields, the phase diagram is dominated by an up-up-down phase. At high fields below saturation, a quadrupolar spin superfluid emerges in the large-$ D_z$ regime, whereas a dipolar spin supersolid with a ‘V’-type spin configuration dominates at small $ D_z$ . These phases are characterized through their order parameters and spin superfluid stiffness using calculations on various system sizes. Furthermore, the dynamical spin structure factor is obtained across the phase diagram, where characteristic spectral signatures of different phases are observed, including the gapless Goldstone mode and the roton-like minima. These features are directly accessible to inelastic neutron scattering experiments. Our results provide a theoretical understanding of the interplay between frustrations, anisotropy, and Zeeman interactions in driving distinct spin supersolid phases in the spin-1 system, which are relevant to various triangular-lattice antiferromagnets such as Na$ _2$ BaNi(PO$ _4$ )$ _2$ and K$ _2$ Ni(SeO$ _3$ )$ _2$ .
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
18 pages, 12 figures
Markov chains at the onset of non-reversibility
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-09-07 20:00 EDT
Gustave Robichon, Cecile Monthus, Werner Krauth
For a one-dimensional path graph and a lifted path graph constructed from a duplication of each of its sites, we study how a reversible Markov chain can be perturbed and gradually driven into non-reversibility. The reversible Markov chain has a transition matrix that is diagonalizable and features real-valued eigenvalues and eigenvectors. The left and right eigenvectors form a biorthogonal system. We discuss in concrete examples how the transition matrix of a non-reversible Markov chain may be diagonalizable or non-diagonalizable, and it may have real eigenvalues and complex-conjugate pairs. For a number of steady states (flat, square-wave, wedge, V-shape), we compute eigenvalue spectra on both graphs and discuss the speedup that can be achieved through lifting. We develop a Green’s matrix formalism, which we use to compute Kemeny times and mean first-passage times, and which provides valuable information and allows us to interpret the results for the characteristic times.
Statistical Mechanics (cond-mat.stat-mech)
44 pages, 6 figures
Ni-O hybridization as a stabilizer for $s^{\pm}$ superconductivity in La$_3$Ni$_2$O$_7$: a DFT+RPA study
New Submission | Superconductivity (cond-mat.supr-con) | 2026-09-07 20:00 EDT
Lauro B. Braz, Daniel D. Rivera, Emmanuel V. C. Lopes, George B. Martins, Gustavo M. Dalpian, Luis G. G. V. Dias da Silva
The superconducting gap symmetry of high-pressure bilayer nickelates remains under debate, with weak- and strong-coupling approaches yielding different pairing tendencies. In this work, we investigate how the weak-coupling treatment of electronic states away from the Fermi level influences magnetic fluctuations and superconductivity in La$ _3$ Ni$ _2$ O$ _7$ . We employ a full-spectrum model based on orthonormalized projections of Kohn-Sham states onto local Ni-$ e_g$ orbitals, which preserves the density-functional band structure while redistributing spectral weight over a wide energy range. Compared to a low-energy description, this approach yields enhanced interlayer spin fluctuations and a commensurate magnetic instability. Within a spin-fluctuation framework, these features favor a sign-changing $ s^\pm$ superconducting state, whereas low-energy models tend to stabilize $ d$ -wave pairing. Our results suggest that interlayer coupling in full-energy models may play an important role in shaping the predicted pairing symmetry of bilayer nickelates.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
13 pages, 9 figures + Supp. Material
Electrostatic splitting of an Edge Magnetoplasmon Resonator
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-09-07 20:00 EDT
Sloän Kouamé, Elric Frigerio, Giacomo Rebora, Suvankar Purkait, Yong Jin, Ulf Gennser, Antonella Cavanna, Jean-Marc Berroir, Emmanuel Baudin, Pascal Degiovanni, François D. Parmentier, Gwendal Fève, Gerbold C. Ménard
Edge-magnetoplasmon resonators have been proposed as a powerful tool to detect anyons by introducing a quantum point contact into an isolated quantum Hall system probed via radiofrequency radiation. In this paper, we study the effect of a quantum point contact embedded within an edge-magnetoplasmon resonator and how its polarization influences the propagating magnetoplasmonic mode. Combining dc and rf measurements, we unambiguously evidence the signature of both integer ($ \nu = 1$ and $ 2$ ) and fractional quantum Hall states ($ \nu = 4/3$ and $ 2/3$ ) within the radiofrequency transmission signal. Using electrostatic gating, we determine the physical parameters characterizing the electrostatic edge of an AlGaAs/GaAs based two-dimensional electron gas. We extract the dependence of the cavity perimeter with the gate voltage of the quantum point contact and fully characterize the path followed by edge magnetoplasmons in this system. Finally, we provide a geometric model in good agreement with experimental results.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Main text 10 pages and 7 figures, supplementary 6 pages and 10 figures
Dynamical Reduction of Two Series Josephson Junctions to a Synthetic High-Transparency Josephson Element
New Submission | Superconductivity (cond-mat.supr-con) | 2026-09-07 20:00 EDT
Claudio Guarcello, Sergio Pagano, Carlo Barone, Alessandro Bruno, A. Mert Bozkurt, Giovanni Filatrella
Two conventional Josephson junctions connected in series can reproduce, in the static limit in which the currents through the capacitive and resistive channels are negligible, the current-phase relation of a single effective weak link with tunable transparency. Therefore, the two-junction series can be treated as a single synthetic high-transparency element. Here, we investigate to what extent this mapping remains valid under finite-frequency drive and retaining the junctions’ resistive and capacitive terms. The full resistively and capacitively shunted junction equations are compared with an effective synthetic element with tunable transparency that retains the synthetic tunable-transparency current-phase relation together with effective capacitive and dissipative terms, thus reducing the two second order degree of freedom system to a single second order degree of freedom. The resulting single-element dynamics is compared with the complete two-junction system under ac excitation. The agreement is quantified through a normalized root-mean-square error between the full and effective voltage waveforms. A broad low-error region is found at low drive frequency, while pronounced deviations emerge as the drive frequency approaches the relevant plasma-frequency scale and at larger drive amplitudes. The results provide a quantitative dynamical criterion for using the reduced single-element description of a synthetic high-transparency Josephson element in superconducting circuits.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
5 pages, 2 figures. Submitted as a WOLTE17 contribution for consideration in the IEEE Trans. Appl. Supercond. Special Issue
Coarse-graining far-from-equilibrium dynamics using oblique projectors
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-09-07 20:00 EDT
We generalize the Mori-Zwanzig projection operator formalism by introducing an oblique projector using biorthogonal variables to coarse-grain the dynamics of systems far from equilibrium, such as active or living matter. Improving on previously used orthogonal projectors, the oblique projector correctly decomposes the emergent interactions of the coarse-grained particles into systematic and stochastic contributions. We show that the formalism directly connects to established results in non-equilibrium linear response theory and adiabatic perturbation theory. Based on this formalism, we develop a coarse-graining algorithm which we apply to extract the emergent non-equilibrium chiral dynamics of a passive tracer in a chiral active bath. Our theory correctly predicts the odd transport properties and a confinement-induced shift of the chiral frequency of the tracer.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
Robustness of RKKY interactions across a Weyl node-annihilation transition
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-09-07 20:00 EDT
João V. F. Alves, Joelson F. Silva, Luis G. G. V. Dias da Silva
Weyl semimetals (WSMs), with their unique topological properties and distinct electronic structure, exhibit intriguing properties when either time-reversal or inversion symmetries are broken. In this work, we consider the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction between magnetic impurities in time-reversal symmetry-breaking WSMs. We derive analytical expressions for the full RKKY exchange tensor in arbitrary two-band spinful lattice systems. Our approach reveals both Heisenberg, anisotropic Ising and Dzyaloshinsky-Moriya terms, which can be calculated by energy-integrating real-space Green’s functions across the entire Brillouin zone, with the band edge acting as a natural energy cutoff. We apply this framework to study a two-band tight-binding model for a time-reversal symmetry-breaking WSM that interpolates between a Weyl phase with well-separated chiral nodes and a quadratic band-touching semimetal phase. Remarkably, the spatial profile, magnitude, and anisotropic tensor structure of the exchange couplings remain persistent across the node-annihilation transition. This topological robustness reveals that short- and intermediate-range RKKY interactions are mediated by the global, Brillouin-zone-integrated quantum metric of the full valence band rather than being strictly dictated by local low-energy Berry curvature monopoles. These findings demonstrate the necessity of full-band tight-binding formulations when predicting real-space magnetic interactions, providing key insights for electric-field tuning of magnetic anisotropy and constructing realistic models of heavy-fermion and Weyl-Kondo semimetals.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
18 pages, 5+5 figures, JPCM format
Diffusion under competing bulk and surface stopping mechanisms
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-09-07 20:00 EDT
We investigate reflected diffusion in a bounded domain subject to two independent, competing stopping mechanisms: an exponentially distributed bulk lifetime of rate $ p$ and a surface reaction triggered when the boundary local time exceeds an independent exponential threshold of rate $ q$ . Denoting by $ T$ the stopping time and by $ L$ the acquired boundary local time at stopping, we derive their marginal distributions, joint Laplace transform, and complete hierarchy of mixed moments. These statistics are determined by the splitting probability $ \phi$ that surface reaction occurs before bulk decay. In particular, we establish the identity $ p\expect{T}+q\expect{L}=1$ and show that the cumulative risk $ pT+qL$ is exponentially distributed with unit rate. We further obtain equivalent representations of $ \phi$ in terms of the Robin-Laplacian and the generalized Steklov spectra. Explicit results for a three-dimensional ball reveal how competing rates $ p,q$ control $ \phi$ and the $ (T,L)$ statistics. Monte Carlo simulations test the universal cumulative-risk law.
Statistical Mechanics (cond-mat.stat-mech), Mathematical Physics (math-ph), Chemical Physics (physics.chem-ph)
18 pages, 9 figures
Connecting heterogeneous dynamics with local entropy
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-09-07 20:00 EDT
Jun Wu, Walter Kob, Yujie Wang, Zhen Zhang
Establishing a robust and physically interpretable link between static structure and heterogeneous relaxation dynamics remains a fundamental challenge in glass physics. Here, we introduce a weighted pair-entropy descriptor based on the conventional two-body excess entropy. For this, we multiply the integrand used to calculate the excess entropy by a weight function that is directly related to the length scale of the pair correlation function. This multiplication does not affect the contribution of the short range order to the local excess entropy, but allows to take into account the structure present on intermediate distances, i.e., the medium-range order. For a canonical two-dimensional Lennard-Jones glass former, the resulting descriptor exhibits a strong correlation with particle-level dynamical propensity at long times (multiples of the alpha-relaxation time), with a maximum structure–dynamics correlation reaching about 0.9, substantially outperforming the predictive power of the conventional local pair excess entropy. These results demonstrate that incorporating a physically motivated structural length scale into entropy-based descriptors markedly enhances their predictive power while preserving physical interpretability. Our findings provide a simple and general framework for investigating structure–dynamics correlations in glass-forming systems.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
Fluctuations of a Photon Bose-Einstein Condensate Coupled to a Reservoir: Describing Coherence Properties in a Free-Energy Model
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-09-07 20:00 EDT
Martin Weitz, Andreas Redmann, Riccardo Panico, Leon Kleeblank, Kevin J.H. Peters, Frank Vewinger, Julian Schmitt
Photons are mutually nearly noninteracting particles, so thermalized photon ensembles are commonly obtained not from direct particle-particle-interactions but rather from contact with matter, which can constitute a reservoir for the photon gas. We develop a theory model for photons in a material-filled (e.g. liquid dye) optical microcavity, with the aim to study the fluctuation properties using a free-energy description for noninteracting photons coupled to a reservoir of material electronic excitations. To begin with, we use a single mode description for the condensate. For a small relative size of the material reservoir, corresponding to the canonical regime, condensate number fluctuations are small, and the derived free energy landscape takes the usual Mexican-hat shaped form such that spontaneous symmetry breaking occurs. In contrast, for a large relative size of the reservoir, corresponding to the grand canonical regime, fluctuations become as large as the average particle number. We show that the resulting free energy landscape acquires a bowl-shaped form, with a single minimum at the origin. Thus, a macroscopic occupation of the ground state (i.e., Bose-Einstein condensation) in the absence of spontaneous symmetry breaking is expected. We also provide a model for the treatment of a photon gas trapped in a box-shaped potential with spatially distributed coupling to a reservoir. The model predicts, for example, a statistically fluctuating pattern of islands with long-range coherence, resembling transient microcondensates.
Quantum Gases (cond-mat.quant-gas)
19 pages, 4 figures
Breakdown of Anomalous Hall Scaling in Dilute Kondo System
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-09-07 20:00 EDT
Arnab Bhattacharya, Prashant Singh, Ajay Kumar, Afsar Ahmed, Yaroslav Mudryk, I. Das, Anis Biswas
The confluence of strong electronic correlations and Berry curvature-driven transport constitutes a largely underexplored frontier in quantum materials research, particularly in systems where electronic correlations arise from flat-band physics rather than conventional $ f$ -electron states. Here, we report an intrinsic Berry curvature driven anomalous Hall transport in the dilute Kondo system Ru$ _2$ Mn$ _{0.5}$ Ti$ _{0.5}$ Ge, a non-$ f$ -electron Heusler alloy hosting flat bands with van Hove singularity proximate to the Fermi level. The anomalous Hall response is strikingly non-monotonic, violating the Fermi-liquid scaling relation near the magnetic transition and is restored only at low temperature, coincident with the onset of Kondo coherence. \textit{Ab initio} calculations strongly establish that the Berry curvature originates from the Kondo hybridization induced interplay of flat bands and spin-orbit coupling mediated anticrossings at the Fermi level. Our findings demonstrate that Kondo coherence of flat bands bears a profound impact on Berry curvature associated ferroic responses, mandating a rigorous theoretical understanding of anomalous transport in the regime where reciprocal space topology and strong correlations are intrinsically intertwined.
Strongly Correlated Electrons (cond-mat.str-el)
How dipolar interactions structure molecular droplets
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-09-07 20:00 EDT
Wiiliam Freitas, Panagiotis Giannakeas, Jan M. Rost
We investigate how dipolar interactions between microwave-shielded polar molecules structure the self-bound droplets formed under variation of the interaction strength. We identify the transition from droplets to crystals as a finite-size first order transition. With droplet-ring states and transitional supersolid states we predict additional structure in the crystal and droplet phases, respectively. To describe this strongly correlated regime, and in particular the reconfiguration of quantum ground states, we design a variational Monte Carlo framework based on neural quantum states. It is especially suitable to describe ground states and almost degenerate states with very different configurations. Moreover, one can easily determine the superfluid fraction. Our results reveal the sequence of finite-size structures through which dipolar interactions reorganize molecular droplets into crystals.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
7 pages, 8 figures
Remote epitaxy beyond polarity
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-07 20:00 EDT
Ching-Tai Fu, Pei-Jan Hung, Xudong Li, Xiaolong Zhu, Yu Han, Sayantan Mahapatra, Zhiheng Zhao, Qingsong Fan, Xubing Wu, Qizhang Li, Chenxi Sui, Zirui Zhou, Ting-Hsuan Chen, Cheng-Hao Lei, Ivan Kuzmenko, Xiaobing Zuo, Byeongdu Lee, Alexander S. Filatov, Jeffrey R. Guest, Fengyuan Shi, Yuzi Liu, Hua Zhou, Yunfeng Shi, Po-Chun Hsu
Remote epitaxy through a monolayer two-dimensional material-covered substrate establishes a crystallographic registry across the van der Waals (vdW) surface that enables the epitaxial growth, lift-off and transfer of single-crystalline films. A central belief in remote epitaxy is that the substrate facilitating the phenomenon must be a material with strong ionicity, as the interatomic electrostatic potential fluctuation in covalent and metallic materials is substantially attenuated by two-dimensional materials. Here, we show remote epitaxy is possible when the substrate is a metallic or covalently bonded material and experimentally demonstrate non-polar remote homo- and heteroepitaxy across a wide range of material systems, including both metals and semiconductors. The achieved non-polar remote interactions are designed and engineered by harnessing substrate conductivity and vicinal surface step-edge density. These findings indicate that remote epitaxy is universal and applicable to ionic, metallic, and covalent materials, expanding its capabilities and stimulating a plethora of new fundamental scientific questions about the mechanism of remote epitaxy.
Materials Science (cond-mat.mtrl-sci)
Molecular interfacial rheology: Lipid membrane shear viscosity
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-09-07 20:00 EDT
We develop a method to extract the shear viscosity of a lipid membrane from equilibrium molecular dynamics simulations. The method characterizes the rheology of general interfacial systems embedded in three-dimensional media; we term it molecular interfacial rheology. In our simulations the planar bilayer and surrounding water are confined between solid, parallel walls. Following Onsager’s regression hypothesis, membrane and water fluctuations are assumed to relax according to the coupled continuum-mechanical equations governing the confined system—which predict that the membrane transverse velocity autocorrelation function (TVACF) decays exponentially, at a rate set by the membrane and water viscosities. The measured TVACF, however, exhibits damped oscillations followed by a slowly decaying tail. We reconcile these behaviors using the Mori–Zwanzig formalism, and extract the wavevector-dependent membrane viscosity from the time-integral of the TVACF. Results from theory and simulations agree over a decade of wavevectors, and extrapolating to long wavelengths yields shear viscosities ranging from 0.064 to 0.18 pN\astus/nm across two representative single-component, fluid-phase bilayers. Our results are corroborated by nonequilibrium simulations where a spatially varying in-plane body force is applied to lipid molecules, thus validating the framework of molecular interfacial rheology.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech), Biological Physics (physics.bio-ph), Fluid Dynamics (physics.flu-dyn)
6 pages, 5 figures, Supplemental Material available at this https URL
Customized spin spirals in ferromagnetic thin films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-07 20:00 EDT
Anjali Panchwanee, Kai Schlage, Dieter Lott, Sven Velten, Thomas Saerbeck, David L. Cortie, Sakshath Sadashivaiah, Ilya Sergeev, Guido Meier, Lars Bocklage, Ralf Röhlsberger
The advancement of spintronic nanoscale devices hinges on the ability to flexibly engineer magnetic spin structures in thin-film stacks with precision and control. Meeting this demand remains a challenge for stable non-collinear spin configurations and, more specifically, vertical spin spirals in thin films. Innovative methods are required for their fabrication, stabilization and control. Here, we use oblique-incidence deposition to design and stabilize vertical spin spirals at room temperature and without an external field in magnetic thin films. We induce two crossed uniaxial magnetic anisotropies at the thin film boundaries. These anisotropies are tunable in direction and strength, thus providing control over the angular range and depth profile of the resulting spin spiral. The combination of polarized neutron reflectometry and nuclear resonant scattering enables precise and direct determination of the depth-dependent spin configurations. Our results establish a single-film design approach, in which the surface anisotropies independently serve as controllable design parameters for tailoring the vertical spin-spiral profile. Potential applications include nanoscale energy-storage devices, magnetic sensors, and ferromagnetic-resonance filters, advancing all-spin-based device engineering in general.
Materials Science (cond-mat.mtrl-sci)
19 pages, 10 figures
Non-reciprocally interacting Ornstein-Uhlenbeck processes: Exceptional points, Anomalous relaxation, Pseudo-equilibrium and Boundary refrigeration
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-09-07 20:00 EDT
Soumya Kanti Pal, Shamik Gupta
Non-reciprocal interactions are ubiquitous in active, biological, and disordered systems, generically driving them out of equilibrium. Here, we introduce a hierarchy of non-reciprocally interacting Ornstein-Uhlenbeck (NROU) models governed by a tunable non-reciprocity parameter $ g$ . At a special point $ g=g^\ast$ , the drift matrix becomes non-diagonalizable, realizing exceptional points (EP’s) of different orders, where eigenvalues and eigenvectors simultaneously coalesce. The hierarchy encompasses non-reciprocally coupled dimers, their disordered counterparts, and a many-body chain exactly mapping onto the paradigmatic Hatano-Nelson model in the arena of non-Hermitian quantum systems. For the disordered model, we show that the distribution of the EP location $ g^\ast$ across disorder realizations develops a universal edge singularity precisely at the clean-system EP, and is manifestly non-self-averaging. Across all models, we find that at the EP, the usual exponential relaxation of the autocorrelation and covariance functions is dressed by a polynomial-in-time prefactor whose degree is set by the order of the EP and whose detailed structure encodes the spatial architecture of the chain. At complete asymmetry, the many-body chain exhibits ``pseudo-equilibrium’’: its steady-state distribution factorizes into equilibrium-like single-particle measures despite a nonzero steady-state current. Moreover, the $ N$ -particle interacting system decomposes into $ N/2$ independent complex OU processes. Finally, using the Harada-Sasa relation, we obtain a closed-form expression for the total steady-state heat dissipation and uncover a boundary refrigeration effect, in which the boundary particles switch from acting as a hot to a cold reservoir as the non-reciprocity is tuned.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
25 pages, 9 figures
From Electronic Structure to Environmental Remediation: Adsorption of Ionized Glyphosate on COOH-Modified Carbon Nanotube
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-07 20:00 EDT
H. T. Silva, L. C. S. Faria, C. Aguiar, T. A. Aversi-Ferreira, I. Camps
Glyphosate is a widely used herbicide whose persistence and toxicity in aquatic and terrestrial environments demand efficient removal strategies. Here we employ GFN2 xTB calculations with implicit ALPB aqueous solvation and automated docking to investigate the adsorption of all five pH dependent ionized forms of glyphosate (G1-G5) on (10,0) single walled carbon nanotubes covalently functionalized with carboxyl groups at 0-25% coverage. Adsorption energies reveal a clear charge dependent trend: the dianionic (G4) and trianionic (G5) species exhibit the most negative binding energies over the entire functionalization range, while the protonated and neutral forms (G1, G2) bind weakly, approaching reversible adsorption at high COOH contents. The deprotonated form G5 strengthens from -2.17 eV on pristine CNT to about -5.7 eV at 10% and 25% functionalization, with a local minimum near 15-20% COOH due to steric and electrostatic crowding of adjacent groups. Decomposition of the solvation free energy shows dominant electrostatic stabilization complemented by increasingly favorable hydrogen bond contributions as carboxyl density grows. All complexes display very small HOMO-LUMO gaps (0.02-0.22 eV), indicating high electronic sensitivity to adsorption and functionalization. Overall, CNT+COOH systems can operate in both strong capture and regenerable regimes depending on glyphosate ionization state, offering a tunable platform for pH responsive remediation.
Materials Science (cond-mat.mtrl-sci)
Variable Charge State, Magnetic Excitations, and Kondo Effect of Sm/g/Ir(111)
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-09-07 20:00 EDT
Shixuan Shan, Tamara de Ara, Lina Liu, Zhipeng Wang, Marina Pivetta, François Patthey, Tadahiro Komeda, Daria Kývala, Jindřich Kolorenč, Harald Brune
Using low-temperature scanning tunneling microscopy we investigate the charge state, magnetic excitations, and Kondo features of individual Sm adatoms on graphene/Ir(111). Depending on the number and distance of their neighbors, Sm atoms can be in two discrete charge states. At certain distances, a reversible transition between these two states is induced by the electric field of the STM tip leading to concentric charge rings in the images. Only atoms in one of the two charge states exhibit magnetic excitations in d$ I$ /d$ V$ spectra. Two such excitations are located at 35meV and 54meV and related to transitions from the $ J = 1/2$ ground state doublet to the first crystal field split $ J = 3/2$ multiplet. Together with the intra-atomic exchange excitations at higher energy, these observations indicate that Sm transfers one $ 6s$ electron to the substrate while it retains its gas-phase $ 4f$ filling. New for lanthanide adatoms, we observe a Kondo resonance. The Zeeman splitting of the Kondo peak reveals that Sm retains its large gas-phase $ g$ -factor. Comparison of d$ I$ /d$ V$ spectra to cotunneling theory yields the crystal field acting on the $ 4f$ shell and, consequently, on the $ J = 3/2$ quadruplet, confirms Sm$ ^+$ as the ground state, and identifies Sm$ ^{2+}$ as being energetically close, thereby rationalizing our observation of variable charge states.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Research Square
Sulfur Addition to Graphene Surfaces Invalidated via Isotopically Pure 13C Graphene
Research Article | Electronic devices | 2026-09-07 20:00 EDT
Richard Martel, Simon Sprocq, Elie Hadad, Leonard Schue, Mohammed Amine-Mezour, Pierre Levesque, Alain Rochefort, Mickael Dollé
Covalent addition and incorporation of sulfur to sp2 carbon surfaces by radical reaction in the gas phase have been reported by a number of studies to explain property changes, such as doping, enhanced mechanical strength and phase changes in graphite superlattices. Here, we investigate the reaction of sulfur radicals to pristine graphene surfaces in the gas phase using advanced surface-sensitive techniques. Consistent with previous works, sulfur bonding is observed at moderate temperature in a gas phase on both few-layers graphene and highly oriented pyrolytic graphite (HOPG). The presence of covalent bonds between carbon and sulfur is confirmed by Raman, photoemission spectroscopies and advanced microscopy. The reaction products are consistent with a stable graphene episulfide structure obtained by DFT calculations, in which the sulfur adatoms are adsorbed at the bridging sites between pairs of sp2 carbons. The covalent bonding to graphene is, however, invalidated by a control experiment using isotopically pure 13C graphene samples. The analysis shows that adsorbed species are rather due to species deposited during the reaction involving residual carbon species introduced during the experiments. Consistent with organo-sulfur deposition at the graphene surface, these experiments reveal no evidence of direct reaction of sulfur with the graphene surfaces. More generally, the use of isotopically pure graphene samples is presented as a general method for future work on graphene functionalization.
Research Square:rs-3562763 (2026)
Posted on Research Square
Physical sciences/Materials science/Materials for devices/Electronic devices, Physical sciences/Chemistry/Materials chemistry/Electronic materials
Broadband Polarization-Agnostic Dispersion Flattening with Gradient ε-and-µ-Near-Zero Photonic Structures
Article | Nanophotonics and plasmonics | 2026-09-07 20:00 EDT
Aaswath Raman, Jae Hwang, Yasunori Kawabe, Mingze He, Andrea Alu, Baolai Liang
Suppressing angular dispersion in nanostructured, ultra-thin materials is a long-standing challenge, particularly when broadband operation and polarization robustness are simultaneously required. Existing polaritonic strategies have achieved angle-robust optical responses, but remain constrained by narrow bandwidths, polarization selectivity, or limited spectral tunability. Here, we introduce a gradient ε-and-µ-near-zero (EMNZ) photonic platform that enables broadband, polarization-agnostic dispersion flattening in the infrared. The platform combines epitaxially grown graded-doped InAs multilayers, whose spatially varying plasma frequency supports a continuum of sub-light-line flat-band polaritonic resonances, with a photonic-crystal superstrate that enables polarization-agnostic coupling into the underlying flat-band modes for both TM- and TE-polarized light. Such response features a polarization vortex originating from a nearby symmetry-protected bound state in the continuum and persisting over a broad spectral range. We experimentally demonstrate two gradient EMNZ structures operating over distinct wavelength bands (12-16 µm and 17-19 µm), both exhibiting broadband angle-robust resonances with minimal spectral shift from normal to 50° incidence under both linear polarizations. Effective-parameter retrieval confirms a spectrally graded near-zero refractive index across each operational band, and near-field calculations reveal wavelength-selective field confinement within individual nanolayers of the gradient stack. By decoupling angular dispersion from both spectral bandwidth and polarization, this work establishes a material-level design framework for angle-insensitive infrared photonic devices, with potential applications in thermal emission engineering and infrared sensing.
Research Square:rs-10809049 (2026)
Posted on Research Square and Under Review at Light: Science & Applications
Physical sciences/Physics/Optical physics/Nanophotonics and plasmonics, Physical sciences/Optics and photonics/Optical physics/Sub-wavelength optics, Physical sciences/Optics and photonics/Optical materials and structures/Metamaterials