CMP Journal 2026-08-31
Statistics
Nature Materials: 1
Nature Physics: 1
arXiv: 77
Research Square: 2
Nature Materials
Tuning moiré twist angles enhances tensile plasticity in bulk van der Waals crystals
Original Paper | Mechanical properties | 2026-08-30 20:00 EDT
Jiali Zhou, Jiawei Zou, Zhiqiang Gao, Jiawei Zhang, Linlin Zhang, Zhi Li, Zhengyang Zhou, Pengfei Qiu, Yang Yang, Qian Yu, Lidong Chen, Xun Shi
Moiré twisting breaks the inherent symmetry of crystal structures, providing a promising method for tuning emergent quantum phenomena and physical properties in layered materials. Here we demonstrate that moiré twisting can also be harnessed to effectively enhance the tensile plasticity of bulk layered van der Waals crystals. We show that interlayer moiré twisting, spanning a broad range of twist angles commensurate with the crystal’s translational symmetry, can be controllably introduced through simple off-axis compression in ternary bulk layered van der Waals crystals. It facilitates efficient stress relaxation under mechanical loading with a further increase in the moiré twist angles and enables a substantial increase by up to 360% in room-temperature macroscopic tensile ductility, reaching 30% tensile strain along the a-b plane. Moreover, moiré twisting occurs only between layers and, thus, negligibly affects the in-plane electronic properties. By establishing tunable moiré twisting as an effective mechanism for plastic deformation, this work provides a broadly applicable strategy for enhancing tensile ductility in bulk layered materials.
Mechanical properties, Two-dimensional materials
Nature Physics
Optical control of electrons in a Floquet topological insulator
Original Paper | Nonlinear optics | 2026-08-30 20:00 EDT
Daniel M. B. Lesko, Tobias Weitz, Simon Wittigschlager, Weizhe Li, Christian Heide, Ofer Neufeld, Peter Hommelhoff
Light-dressed materials offer a route to generating electronic properties that differ from those of materials at equilibrium. The resulting band structures can host distinct quantum and topological phenomena. So far, optical control of charge within a light-dressed band structure has remained elusive. Here we demonstrate optical control of electrons in light-dressed graphene. By focusing circularly polarized femtosecond laser pulses at 1,550 nm on monolayer graphene, we generate a Floquet topological insulator. With a phase-locked second-harmonic field, we dynamically control electrons in this state, a technique we call harmonic Floquet spectroscopy. We observe photocurrent circular dichroism, an all-optical anomalous Hall effect and valley-polarized currents. The photocurrents show strong subcycle phase sensitivity, suggesting a route to ultrafast control in topological electronics, spectroscopy and attosecond physics in quantum materials.
Nonlinear optics, Topological insulators, Ultrafast photonics
arXiv
Exact branch-transfer criterion for common-mode Thomson heat cancellation in thermoelectric couples
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-31 20:00 EDT
Peng Kang, Da Wan, Shulin Bai, Wei Yin, Peng Wang, Chenglong Wen, Zhen Li, Yu Liu, Lei Zheng, Li-Dong Zhao
Thermoelectric p- and n-type legs are commonly paired by matching their Seebeck magnitudes, although a cooler responds to heat transported through its complete electrical and thermal network. We decompose the leg coefficients into differential thermopower $ \alpha=S_p-S_n$ and common thermopower $ M=(S_p+S_n)/2$ . In a connected steady-state scalar thermoelectric network, a temperature-independent co-shift applied to every electrically active segment is an exact terminal null. A temperature-dependent perturbation of the legs relative to fixed leads is instead physical. At fixed current and shared isothermal endpoints, its first-order cold-port response is the action of $ \Gamma_m=T,dm/dT$ on the difference between the p- and n-branch oriented collection measures. We prove that every continuous $ \Gamma_m$ cancels if and only if these measures are equal. In the constant-property, linear-common-mode limit, matching $ R_i/K_i^{\rm leg}$ is sufficient and does not require identical legs. One- and two-dimensional calculations confirm the analytic reductions within their stated domains. For split thermal pads, the analysis gives the exact array law $ \Delta Q_{c,\Sigma}=\sum_j C_jI_j\Delta T_{c,j}$ and, for series elements with isothermal hot pairs, $ I\Delta V_\Sigma=-\Delta Q_{c,\Sigma}$ . A representative seven-pair model gives corresponding increments of 7.87 mW and $ -2.80$ mV. Branch transfer and endpoint topology therefore provide distinct material-pairing and device-test criteria for common-mode Thomson heat.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
38 pages, 5 figures
Asphericity Lifts the Degeneracy Among Ordering Mechanisms on Curved Surfaces
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-08-31 20:00 EDT
Spherical surfaces conceal the one-body signature of particle organization: area-uniform, conductor, and curvature-weighted measures coincide there, so the ordering mechanism leaves no trace in the density. Aspherical deformation lifts this degeneracy. On an ellipsoid, these ordering mechanisms separate into distinct powers of the distance from the shell center to its tangent plane. To leading order in deformation, the characteristic exponent can be read from both the structure factor quadrupole and the radius of gyration. Two interaction families realize the exponent in complementary ways: the Riesz $ s$ -energy, whose limiting measure switches sharply at the marginal power, and screened Coulomb potential, where the exponent is tuned continuously by the salt concentration. Ionic strength thereby becomes an experimental dial that transforms the particle ordering across the conductor-to-packing crossover on a fixed aspherical surface, turning a macroscopic shape parameter into a probe of the microscopic interaction law.
Soft Condensed Matter (cond-mat.soft)
8 pages, 3 figures
Ab initio Modeling of MoS2/Oxide Device Interfaces with Machine Learned Electronic Structures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-31 20:00 EDT
Manasa Kaniselvan, Mauro Dossena, Denghui Lu, Alexander Maeder, Nicolas Vetsch, Alexandros Nikolaos Ziogas, Mathieu Luisier
We introduce a new ab initio approach to simulate semiconductor devices that integrates scalable machine-learned (ML) electronic structure models with an advanced quantum transport (QT) solver. The developed framework enables 10,000X speedups over density functional theory to produce the Hamiltonian matrix of devices made of >20,000 atoms, while offering high prediction accuracy. We use its unique features to investigate MoS2/oxide samples and single-layer MoS2 field-effect transistors, where the surrounding oxide layers, here, HfO2 or Al2O3, are explicitly included into the QT domain. In particular, we reveal that the presence of undercoordinated metal atoms (Hf or Al) close to the semiconductor-oxide interface significantly affects the magnitude of the electronic current and its propagation through MoS2.
Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG)
Collinear altermagnetism for 3D chiral higher-order topological insulators
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-31 20:00 EDT
Andreas Hadjipaschalis, Jennifer Cano
Despite significant progress in the study of higher-order topological insulators (HOTIs), the chiral $ C_4\mathcal{T}$ -protected HOTI has remained elusive in electronic materials, where $ C_4\mathcal{T}$ denotes the product of a four-fold rotation and time-reversal symmetry. We show that altermagnetism, a recently discovered form of collinear magnetism, provides a new route to realize this elusive phase. Specifically, we construct a microscopic model that combines a three-dimensional topological insulator with a collinear $ d$ -wave altermagnet on a Lieb lattice. Through analytical and numerical calculations, we show that the magnetism shifts and gaps the surface Dirac cones to produce the desired chiral hinge channels. Finally, we identify promising material classes to realise our proposal. Our results establish collinear altermagnetism as a route to intrinsic chiral higher-order topology and open a new path toward the discovery of $ C_4\mathcal{T}$ -protected HOTIs in real materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
10 pages, 4 figures
Scale-free correlations in extremely persistent active matter
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-08-31 20:00 EDT
Scale-free correlations are believed to be generic in out of equilibrium systems but their explicit derivations are rare and often involve approximations. Here we analyze a system of infinitely persistent active Brownian particles in the low density and small-swim-velocity limit. We show that both the density and swim velocity correlations decay algebraically as r^{-(d+1)} (with logarithmic corrections in d=2). In reciprocal space these correlations manifest themselves as cusps at k=0. The analytical predictions are confirmed by numerical simulations. The results were obtained through interaction with Claude (Opus 4.8 and 5, and Fable 5) and verified by the author.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
5 pages, 3 figures
Compiling Chemical Knowledge into Executable Descriptors for Materials Prediction
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-31 20:00 EDT
Jaehwan Choi, Kunik Jang, Seongmin Kim, Shuan Chen, Kyungju Nam, Seung Hyo Noh, Donghwi Kim, Yousung Jung
Materials prediction depends critically on how scientific knowledge is represented, yet many governing considerations exist only as natural-language heuristics that conventional learners cannot use. We introduce CRISP, a large language model-assisted framework that treats representation construction as a rule-space exploration and compilation problem: it repeatedly samples target-relevant chemical rules without access to structures, labels or data splits, consolidates related concepts, and compiles each into an executable scalar descriptor supplied to a conventional learner. For positive-unlabeled inorganic-crystal synthesizability, CRISP outperformed expert-curated and generic structural representations under a shared learner and surpassed purpose-built synthesizability models, with its advantage most pronounced under structural-size and chemical-family shifts. Infrequently generated rules contributed complementary predictive information, showing that generation frequency does not determine utility. The same workflow yielded competitive representations for formation energy and ionic conductivity while revealing task-dependent limits for shear modulus, establishing a dataset-blind, auditable route from broad chemical knowledge to transferable computational representations.
Materials Science (cond-mat.mtrl-sci)
Topological signatures in the quench dynamics of periodically driven quantum systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-31 20:00 EDT
Ashutosh Dubey, Hironmoy Pratihar, Diptiman Sen, Arijit Kundu
We study the quench dynamics of graphene, without and with a staggered mass, following the sudden switch-on of circularly polarized light where coupling to a fermionic bath is also considered. Using an armchair nanoribbon, we compute the period-averaged bond current near the edge at successive stroboscopic times. For the isolated system, the current oscillates around a dc value which, we analytically show, equals the Floquet band currents weighted by their projected occupations; a nonzero dc current signals an induced topological phase. When coupled to a bath with a finite coupling, the current and conductance initially increase and then saturate, indicating a nonequilibrium steady state. In the limit of vanishingly small coupling, the period-averaged conductance becomes quantized after summing over bath chemical potentials shifted by integer multiples of the driving frequency, revealing the number of edge modes crossing the zero-quasienergy gap and the Floquet zone boundary gap. We support these results by computing the two-terminal conductance of a finite-size tight-binding model under a three-step driving protocol; the bond conductance after applying the sum rule corroborates our findings.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
18 Pages, 9 Figures
Atomistic Indicators of the Ductile-to-Brittle Transition in Polycrystalline Tungsten: Temperature and Rhenium Effects on Crack-Tip Plasticity
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-31 20:00 EDT
The fracture response of body-centered-cubic tungsten is governed by competition between crack-tip instability and dislocation-mediated plastic accommodation. Molecular dynamics (MD) simulations are used to examine edge-cracked polycrystalline W and W-Re under displacement-controlled Mode-I tension from 300-1800 K at a strain rate of 5 x 10^8 s^-1. Heating pure W reduces the instability stress, effective specimen stiffness, and pre-instability volumetric work density, while the instability strain remains comparatively scattered. A normalized work-loss metric derived from the pre-instability work gives a broad sigmoid crossover marker, T\ast_MD ~ 870 K, characteristic of the simulated geometry and high-rate loading conditions. Among the available W-Re compositions, W-10Re shows greater pre-instability deformation and work accumulation than pure W across most temperatures, while the maximum-stress response remains strongly temperature- and composition-dependent. Changes in retained dislocation character and near-tip activity indicate that Re modifies the crack-tip plastic-accommodation pathway rather than producing a simple strength increase. Common-state analysis further shows that Re alters the retained 1/2<111> line character and the temporal distribution of near-tip dislocation activity without uniformly increasing the local dislocation population. These coupled mechanical and defect-structure changes provide atomistic indicators of a high-rate ductile-to-brittle transition (DBT), but not a direct prediction of experimental DBTT. A separate OpenDiS/pydis calculation demonstrates source-like bow-out and heterogeneous dislocation-network development in crack-free polycrystalline W, providing mesoscale context without implying direct quantitative MD-DDD coupling.
Materials Science (cond-mat.mtrl-sci)
Physics-informed learning for the inverse problem in resonant ultrasound spectroscopy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-31 20:00 EDT
Alejandro Cubillos Muñoz, Manuela Rivas, Julian Rincon
Inferring elastic constants from resonant ultrasound spectra is a nonlinear and typically overdetermined inverse problem based on finite spectral data. We formulate the Rayleigh-Ritz inverse problem as a constrained inverse-isospectral problem on the set of physically admissible elasticity tensors. This induces effective low-dimensional variables for the inverse map on the admissible elasticity manifold: length and elastic scales, aspect-ratio coordinates, scale-free spectral features, and stability-respecting elastic ratios. We use these variables to construct a physics-informed learning pipeline in which a regression model acts only on reduced spectral and geometric features, while scale recovery and final elastic-constant reconstruction are imposed analytically. For the full cubic benchmark, the reconstructed constants have MAE values of $ 20.37(35.15)$ , $ 24.30(41.33)$ , and $ 2.13(3.66)~\mathrm{GPa}$ for $ C_{11}$ , $ C_{12}$ , and $ C_{44}$ . In the fixed-geometry benchmark, the corresponding cubic MAPE values are $ 4.14(3.87)%$ , $ 8.31(8.50)%$ , and $ 2.44(2.86)%$ , while the isotropic values are $ 4.0(3.6)%$ and $ 0.4(0.3)%$ for the bulk and shear moduli. The inverse problem then becomes a constrained regression problem in variables adapted to the geometry, scaling, crystal symmetry, and thermodynamic stability of Hookean elasticity.
Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG), Applied Physics (physics.app-ph), Computational Physics (physics.comp-ph)
15 pages, 8 figures, 3 tables
Turning Zeeman splitting into switchable charge polarization in a double quantum dot
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-31 20:00 EDT
A magnetic field that acts identically on two quantum dots is not expected to move charge between them. Nevertheless, we show that a uniform Zeeman field can strongly reconfigure and even reverse the single-electron charge polarization of an asymmetric open double quantum dot. Using a symmetry-preserving Green’s-function equation-of-motion approach, we identify regimes where the preferred dot occupation reverses while the system remains in the single-electron charge sector. Two distinct mechanisms produce this behavior. Unequal gate levels produce different occupation responses because the Zeeman-shifted resonances lie at different positions relative to the reservoir chemical potential, whereas unequal onsite interactions distinguish the dots through their many-body addition spectra. Coulomb blockade stabilizes the single-electron sector, causing the reservoir-mediated response to appear as spatial charge redistribution rather than a change in total occupation. Our results establish a mechanism for magnetic control of charge polarization at fixed electrostatic detuning.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
LDA-1/2 for Molecular Systems: A Real-Space Finite-Element Benchmark on the GW100 Set
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-31 20:00 EDT
Dongming Li, Niamh Matthews, Qingchuan Sang, Eric Polizzi
The LDA-1/2 method provides an efficient correction to semilocal density functional theory for improving ionization energies and band gaps, yet its application to molecular systems has remained limited. In this work, we present an all-electron finite-element implementation of LDA-1/2 within the NESSIE electronic-structure framework and apply it to the GW100 molecular benchmark set with systematically controllable numerical accuracy. The self-energy correction is constructed explicitly from neutral and half-ionized calculations for each molecule, avoiding the use of precomputed atomic correction potentials. The real-space finite-element formulation enables systematic convergence with respect to the discretization and provides a controlled assessment of LDA-1/2 performance. For the GW100 set, the present implementation yields a mean absolute error of 0.472 eV and a root-mean-square error of 0.645 eV relative to CCSD(T) reference ionization energies, substantially improving upon conventional LDA and the previously reported LAPW implementation of LDA-1/2, while achieving accuracy comparable to G0W0@PBE. Convergence tests show that third-order finite elements are sufficient to reach or approach chemical accuracy relative to higher-order calculations for the representative systems considered. The resulting corrected Hamiltonian also improves several lower lying valence states relative to LDA, although the improvement becomes less systematic away from the HOMO. This work provides accurate LDA-1/2 benchmark data for molecular systems and establishes a rigorous finite-element foundation for future molecular GW calculations.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph), Computational Physics (physics.comp-ph)
First-Principles DFT Study of Ferroelectric-to-Antiferroelectric Phase Transitions in LiTaO$_3$ under Electric Boundary Conditions
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-31 20:00 EDT
Ferroelectric and antiferroelectric phases of LiTaO$ 3$ compete under different electric boundary conditions. First-principles density-functional calculations show that the high-symmetry reference structure supports two relevant unstable $ \Gamma$ modes: a polar $ A{2u}$ mode at $ 181i$ cm$ ^{-1}$ that condenses into the ferroelectric (FE) phase, and an antipolar $ A_{2g}$ mode at $ 103i$ cm$ ^{-1}$ that condenses into the antiferroelectric (AFE) phase. Under short-circuit conditions the FE phase is the global minimum, with a well depth of $ \approx 144$ meV. Under open-circuit conditions the FE phase is destabilized by the unscreened depolarization field and the AFE phase becomes the ground state, with a well depth of $ \approx 19$ meV. A weakly unstable longitudinal-optic mode at $ 48.3i$ cm$ ^{-1}$ yields a well of only $ \approx 0.24$ meV and is thermodynamically irrelevant. Mapping the free energy versus electric displacement $ D$ locates a second-order FE$ \leftrightarrow$ AFE transition at $ D_c=0.051$ C/m$ ^2$ , lower than the corresponding $ 0.07$ C/m$ ^2$ in LiNbO$ _3$ and therefore more accessible experimentally.
Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
Adaptive workforce exploration in complex productivity landscapes
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-08-31 20:00 EDT
Mateus F. B. Granha, Igor V. G. de Oliveira, André L. M. Vilela, Chao Wang, Paulo R. A. Campos
Specialization and task allocation enhance efficiency and innovation across diverse systems, from biological organisms to socioeconomic institutions. The evolution of task distribution and its influence on organizational productivity encapsulate the dynamics between task dependencies and adaptive strategies. We explore the organizational division of labor, inspired by the NK model of rugged landscapes, which is widely applied in evolutionary biology, and incorporate interdependencies among the attributes of technical experts within an organization. Our model considers two types of employees characterized by their task allocation strategies: specialists, who are permanently assigned to a single task, and generalists, who stochastically select a task at each time step. We investigate how the ruggedness of the productivity landscape, shaped by task interdependency, affects the organization’s capacity to optimize labor division and meet market demands. Using group selection algorithms, we reveal the emergence of nonlinear adaptive dynamics, providing insights into how companies can adapt their strategies to meet market demands and foster innovation.
Statistical Mechanics (cond-mat.stat-mech)
17 pages, 9 figures, 1 table
Bound state of a He-3 atom at free He-4 surfaces
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-08-31 20:00 EDT
Quantum Monte Carlo simulations confirm the existence of a bound state of a single He-3 atom at a free superfluid He-4 surface in three dimensions, localized within a ~10-A thick low-density He-4 surface layer, with a binding energy of approximately 4 K with respect to vacuum. As the temperature is raised above ~ 1 K the He-3 atom leaves the surface to dissolve into the superfluid. The situation is entirely different in two dimensions, as the He-3 atom is excluded from the superfluid and no surface bound state exists. Results are also presented for the a He-3 atom binding to nanoscale size He-4 clusters adsorbed on weak substrates, a physical system that may allow for the observation of some of the physics predicted for extended surfaces. It is shown that a He-3 bound state localized at the perimeter of sufficiently small (a few tens of atoms) clusters exists not just on Cs, as previously reported, but on all alkali substrates.
Statistical Mechanics (cond-mat.stat-mech)
7 pages, 6 figures
Efficient perturbations for basin hopping in amorphous glasses
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-31 20:00 EDT
Coraline Du, Hye Sol Kim, Scott C. Warren
Efficient exploration of the complex potential-energy landscapes of amorphous materials is central to computational structure discovery and refinement. Conventional Monte Carlo, reverse Monte Carlo, and related methods typically sample configuration space through small, local trial moves and may require millions to tens of millions of moves to converge. Here, we evaluate larger, nonlocal perturbations followed by local geometry relaxation as an alternative sampling strategy. We develop and test four perturbation types using amorphous Al$ _2$ O$ _3$ as a model system. Among them, moving an oxygen atom to change the coordination numbers of two aluminum atoms, allows access to low-energy configurations with substantially fewer trial moves than a conventional Monte Carlo trajectory. These results suggest that relaxation-assisted nonlocal moves could reduce trapping in local minima and improve sampling in structure-search and reverse Monte Carlo workflows.
Materials Science (cond-mat.mtrl-sci), Disordered Systems and Neural Networks (cond-mat.dis-nn)
10 pages, 3 figures, 2 tables
Migration of inflated cavities in graded hyperelastic solids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-08-31 20:00 EDT
Zhiren Zhu, Jonathan B. Estrada
The inflation of a pre-existing, fluid-filled cavity is a timeless topic in the finite-deformation analysis of soft materials. However, classical solutions for cavity inflation rely on radially symmetric material properties, leaving unresolved the effects of non-radial stiffness heterogeneity that are commonly present in biological tissues and engineered soft materials. In this work, we investigate the quasi-static inflation of a pressurized cavity in a hyperelastic solid with shear modulus varying monotonically along a reference Cartesian direction. Finite-element simulations reveal that, beyond an initial small-inflation regime, the most pronounced symmetry-breaking response is the migration of the cavity toward the more compliant end of the material, while nonspherical distortion remains comparatively weak. To analytically quantify this migration-dominated response, we develop a Rayleigh–Ritz reduced-order framework to determine the strain-energy-minimizing migration amplitude for prescribed gradation parameters and inflation level. Without using fitted parameters, the Rayleigh–Ritz framework recovers key features of the cavity migration that are intimately linked to the mechanical gradation parameters. The identification of centroid migration as a salient geometric signal, together with the reduced-order prediction of its evolution, suggests a roadmap for inverse characterization of graded materials through cavity-inflation experiments.
Soft Condensed Matter (cond-mat.soft)
Dilute-Limit Defect Displacements Enabled by Brillouin-Zone Sampling
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-31 20:00 EDT
Mark E. Turiansky, John L. Lyons, Noam Bernstein
Defects and their interaction with the semiconductor host lattice play an essential role in a variety of technologies. When a defect transitions between two electronic states, the lattice distorts in response. Large displacements occur near the defect, inducing displacements on neighboring atoms, and so on, producing small displacements on atoms hundreds of Ångströms from the defect. Describing these displacements accurately is challenging for first-principles calculations due to limited supercell sizes. Here we demonstrate a procedure to efficiently obtain dilute-limit atomic displacements, using information obtained in typical modest supercells. In our approach, the atomic displacements are first obtained in a small supercell and converted into a force difference under a harmonic potential energy surface. The force difference and phonon modes at different $ {\bf q}$ -points are then unfolded into the Born-von Kármán supercell to obtain the dilute-limit atomic displacements. We critically analyze the convergence behavior of the force difference and study possible electron density differences that give rise to those forces, arguing that modest supercells are sufficient for internal transitions and bound-exciton transitions. Two example applications of our approach are given: (1) we calculate the luminescence spectrum of the NV center in diamond and the T center in Si and (2) we obtain dilute-limit configuration coordinate diagrams for these defects. In particular, we find that coupling to acoustic phonon modes reduces the accepting-mode frequency in the configuration coordinate diagram. Our work provides the missing ingredients necessary to address truly dilute-limit transitions at defects.
Materials Science (cond-mat.mtrl-sci)
Electronic structure, magnetic interactions, and magnonics of 2D trichloride materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-31 20:00 EDT
Krishna Prasad Chapai, Yogendra Limbu, Gopi Chandra Kaphle, Durga Paudyal
Using advanced density functional theory, this study demonstrates the robust thermodynamic, structural, and dynamical stability of pristine, 3d-doped (Ti, Cr), and 4f-doped (Ce) transition metal trichlorides (MCl3). While standard generalized gradient approximation (GGA) incorrectly predicts metallic behavior, hybrid functional calculations successfully capture their semiconducting nature, yielding accurate band gaps of 2.54 eV (VCl3), 4.01 eV (CrCl3), and 2.61 eV (TiCl3). These materials exhibit intrinsic ferromagnetism, with CrCl3 displaying overlapping topological features in both its magnon and phonon dispersions along the high-symmetry K direction, which induces magnon-phonon coupling. Incorporating 3d dopants into VCl3 successfully tunes the bandgap (1.32 eV for Ti and 2.74 eV for Cr) without destroying ferromagnetism, while 4f Ce-doping in CrCl3 introduces localized states below the Fermi level that yield strong nearest-neighbor exchange coupling. Ultimately, this electronic and magnetic tunability highlights the potential of these 2D trichlorides in advanced spintronic functionalities.
Materials Science (cond-mat.mtrl-sci)
10 pages, 8 figures
Compositionally Complex Ceramics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-31 20:00 EDT
The development of high-entropy ceramics (HECs) over the past decade has extended the high-entropy concept to a diverse range of oxides, borides, silicides, carbides, nitrides, fluorides, silicates, and other ceramic solid solutions, encompassing increasingly diverse crystal structures and bonding characteristics and exhibiting a broad spectrum of promising mechanical, thermal, and functional properties. Initial studies predominantly focused on five-component equimolar compositions, often assuming the formation of random solid solutions. More recently, 10-21 component ultrahigh-entropy ceramics have been developed as a subset of HECs, some of which exhibit intriguing abrupt phase transitions. In 2020, we proposed extending the exploration of HECs to the broader class of “compositionally complex ceramics” (CCCs), in which non-equimolar compositions and long- and short-range order reduce configurational entropy while providing additional opportunities to tailor and enhance materials properties, thereby outperforming their higher-entropy counterparts. Dual-phase CCCs have also been reported, with thermodynamic equilibria governing cation partitioning between the two phases and offering further opportunities to control and enhance properties through microstructural engineering. Subsequent studies have revealed grain-boundary phase-like transitions in CCCs that can control microstructural evolution and materials properties. Overall, CCCs offer a versatile platform for tailoring materials properties through diverse crystal structures and bonding characteristics, compositional complexity, non-equimolar designs, long- and short-range order, defects, and microstructural and interfacial engineering.
Materials Science (cond-mat.mtrl-sci)
26 pages, 8 figures
Subcritical bifurcation and on-off bistability in ballistic polariton condensates
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-31 20:00 EDT
Oleg I. Utesov, Soohong Choi, Pavel Kozhevin, Min Park, Daegwang Choi, Hyungdo Lee, Alexey N. Osipov, Alexey V. Yulin, Se Kwon Kim, Yong-Hoon Cho, Igor S. Aranson, Hyoungsoon Choi, Anton V. Nalitov, Sergei V. Koniakhin
Dynamics of exciton-polariton condensates under continuous-wave incoherent Gaussian optical pumping is considered. It is shown that the conventional supercritical Stuart-Landau picture is invalid in a certain domain of the parameter space. For strong polariton repulsion from the reservoir and relatively small pump spots, the dynamics is adequately described by the quintic Stuart-Landau equation. The corresponding subcritical pitchfork bifurcation leads to condensate formation, accompanied by bistability between the trivial and nontrivial states over a finite pump-power range and a one-bit memory. Further increase of the repulsion parameter or decrease of the spot size breaks down the perturbative approach and leads to a peculiar self-trapping regime with complex dynamics. Experimental evidence of the emergence of the proposed behavior is provided. Our findings can be used to design polaritonic setups that exploit the predicted memory effect.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics)
12 pages, 7 figures
Ionization Energies, Electron Affinities, Bandgaps, Exciton Binding Energies, and Polarization Energies of Orientation-Controlled Picene, [6]-Phenacene, and [7]-Phenacene Thin Films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-31 20:00 EDT
Rintaro Makino, Mihiro Kubo, Keiichirou Yonezawa, Hiroyuki Yoshida, Satoshi Kera
Phenacenes, in which benzene rings are fused in a zigzag manner, are chemically robust $ \pi$ -conjugated hydrocarbons of interest for organic electronic applications and superconductivity. However, quantitative electronic parameters of phenacene thin films remain limited compared with those of acenes. Here, we determine the ionization energies (IEs), electron affinities (EAs), band gaps, exciton binding energies, and polarization energies of orientation-controlled thin films of picene, [6]-phenacene, and [7]-phenacene using ultraviolet photoelectron spectroscopy and low-energy inverse photoelectron spectroscopy. The energy parameters depend only weakly on molecular size. In contrast, both IE and EA exhibit large orientation-dependent shifts of approximately 1 eV: lying films show IEs of 6.41-6.43 eV and EAs of 2.16-2.42 eV, whereas standing films show IEs of 5.44-5.67 eV and EAs of 1.36-1.53 eV. Nevertheless, the band gaps of approximately 4 eV and exciton binding energies of approximately 1 eV remain nearly independent of molecular size and orientation. Analysis of polarization energies shows that the induction term is nearly orientation independent, whereas the electrostatic term strongly depends on orientation and originates primarily from molecular quadrupole moments. These results identify molecular orientation as a key factor governing frontier energy levels in phenacene thin films.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
Microscopic Theory of Drag in a Bose Condensate Interacting with a Moving Reservoir
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-08-31 20:00 EDT
Hassan Alnatah, Shuang Liang, Shouvik Mukherjee, Qi Yao, Ashton S. Bradley, David W. Snoke
We derive a microscopic theory of drag for a Bose-Einstein condensate interacting with a moving reservoir. Starting from interactions between a condensate and a drifting fermionic bath, we integrate out the bath degrees of freedom within the Born–Markov approximation to obtain an effective Gross–Pitaevskii equation with a drag potential. From this potential we derive an effective drag force and obtain a closed expression for the drag coefficient, determined by the reservoir density fluctuations and the condensate density profile. As an application, we simulate the drag for an exciton–polariton condensate interacting with a drifting electron gas.
Quantum Gases (cond-mat.quant-gas)
Orbital-Selective Coexistence of Interlayer Spin-Singlet Formation and SDW Order with Anomalous Spin Reconfiguration in Bilayer Nickelate La${3}$Ni${2}$O$_{7}$ Revealed by $^{17}$O-NMR
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-08-31 20:00 EDT
H. Lee, M. Yashima, M. Kakoi, T. Ino, Y. Arai, K. Kitagawa, H. Sakurai, Y. Takano, K. Kuroki, H. Mukuda
The spin structure of the spin density wave (SDW) order in the bilayer nickelate La$ 3$ Ni$ 2$ O$ 7$ has been investigated using site-selective $ ^{17}$ O-NMR measurements on the inner apical O(1), outer apical O(2), and planar O(3,4) sites. Below $ T{\rm SDW}$ (= 150 K), the peak of all planar O(3,4) sites significantly broadens due to the emergence of a finite internal magnetic field, whereas O(2) sites remain with no (or a negligibly small) internal field. These results are consistent with commensurate SDW order with a single spin-spinless (or large-tiny spin) stripe. As for the O(1) sites that bridge the NiO$ 2$ planes, the internal field is nearly canceled below $ T{\rm SDW}$ , indicating an antiparallel spin configuration between adjacent planes. However, below $ T\text{A}$ ($ \sim$ 115 K), the spectrum of the O(1) site disappears even though the in-plane SDW order remains robust, implying that the antiparallel spin configuration through the Ni–O(1)–Ni bond is not particularly stable below $ T{\rm A}$ , despite the expected strong interlayer spin coupling between the NiO$ 2$ planes. Above all, we emphasize that the local spin susceptibility is extremely small at the O(2) site that has a strong covalency with the $ d{3z^2-r^2}$ orbital, indicating a well-developed interlayer spin-singlet formation in the Ni-$ d_{3z^2-r^2}$ orbitals bridging the NiO$ _2$ planes. These findings shed new light on the interlayer spin-singlet formation and the anomalous spin reconfiguration through the $ \text{Ni–O(1)–Ni}$ bonding orbitals connecting the NiO$ _2$ planes, which characterize the orbital-selective nature of the bilayer nickelate La$ _3$ Ni$ _2$ O$ _7$ .
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
9 pages, 4 figures. Accepted for publication in J. Phys. Soc. Jpn
Steady shear rheology of a granular crystal containing a single dislocation
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-08-31 20:00 EDT
Fumiaki Nakai (The University of Osaka)
Monodisperse granular particles can form crystals whose yielding behavior is strongly affected by dislocations and differs markedly from that of conventional amorphous granular materials. Yet the rate dependence of their post-yield steady rheology remains unclear. We use the discrete element method to study steady shear in a granular crystal containing a single dislocation. We find that the steady shear-to-normal stress ratio $ \mu_b$ is organized by the scaled dislocation velocity $ v_d/v_s$ , rather than by the conventional inertial number $ I$ . Here, $ v_d$ is related to the imposed shear rate through Orowan kinematics, and $ v_s$ is a characteristic Hertzian elastic-wave speed. At low $ v_d/v_s$ , the stress ratio approaches a small plateau associated with the elastic lattice barrier and interparticle friction. At intermediate values of $ v_d/v_s$ , contact damping strongly affects the approximately linear increase of the stress ratio above the plateau. As $ v_d/v_s$ approaches unity, the stress develops a stronger nonlinear velocity dependence. At still higher velocities, the coordination deficit rises sharply, marking the breakdown of crystalline order and the end of the single-dislocation description. These results identify the scaled dislocation velocity as the relevant rate variable for the steady rheology of dislocation-mediated granular flow and clarify the distinct roles of interparticle friction and contact damping in the low- and intermediate-velocity regimes, respectively.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
10 pages, 7 figures. Data and code: this https URL
The thermodynamic freedom of a thermodynamic computer
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-08-31 20:00 EDT
Thermodynamic computers are stochastic physical devices designed to perform calculations at the thermal energy scale. Their operation is constrained by the equations of stochastic thermodynamics, among which are a set of bounds, known as speed limits, that relate a thermodynamic computer’s run time to its computational progress and the heat it dissipates. Using the Wasserstein speed limit we assess the thermodynamic efficiency of a simulation model of a thermodynamic computer trained to perform a standard machine-learning classification task. On this task the thermodynamic computer is as capable as a simple multilayer perceptron. We show that different inference protocols allow the computer to operate within 40% of the thermodynamic limit of efficiency without loss of accuracy, or to perform inference increasingly rapidly at fixed accuracy and thermodynamic efficiency. These results indicate that a thermodynamic computer designed for a particular task retains considerable freedom in its thermodynamic operation.
Statistical Mechanics (cond-mat.stat-mech), Neural and Evolutionary Computing (cs.NE)
Quantum geometric bounds at finite temperature for one-dimensional chiral systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-31 20:00 EDT
Peng He, Hai-Tao Ding, Yu-Guo Liu
The geometry and topology of quantum states are intimately related at zero temperature through exact bounds that constrain geometric quantities from below by topological invariants. At finite-temperature, however, the analogous relations remain unclear. Here we establish rigorous geometric lower bounds for one-dimensional (1D) chiral-symmetric systems at finite temperature within the Uhlmann’s framework for mixed states. We show that the Bures length is bounded by a continuous geometric phase angle. We further derive a temperature-dependent bound that interpolates between the zero-temperature limit and a trivial high-temperature regime. Our results are verified analytically and numerically using the Su-Schrieffer-Heeger (SSH) model and the spinless Kitaev chain model. Finally, we discuss potential ways to detect the geometry of the density matrix in quantum circuits, with the quantum imaginary time evolution (QITE) method.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
9 pages, 3 figures
Coherence Resonance Phenomena in an Atom-Dimer Two Mode BECs
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-08-31 20:00 EDT
We investigate the non-equilibrium dynamics of atomic-molecular Bose-Einstein condensates coupled via a Feshbach resonance, with Gaussian white noise acting on both the coupling strength and the detuning. Using the bosonic Josephson-junction and Bloch-sphere formalisms, we examine how coherence (coupling) noise and imbalance (detuning) noise modify the coherence-resonance point as functions of the initial polarization and the Feshbach detuning. Noise plays a more coherent role when its characteristic timescale matches the intrinsic timescales of the dynamics, leading to extrema in the time-averaged purity and the Husimi-Q distribution.
Quantum Gases (cond-mat.quant-gas)
12 pages, 8 figures, and 4 tables
Multi-dimensional spectroscopy of mobile excitons in two-dimensional semiconductors
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-31 20:00 EDT
Ned Wheaton, Jeffrey A. Davis, Jesper Levinsen, Meera M. Parish
Multi-dimensional coherent spectroscopy (MDCS) goes beyond standard linear-response probes and provides a powerful tool for investigating correlations between quasiparticles such as excitons (bound electron-hole pairs). Here we present a microscopic theory of MDCS that accounts for the delocalized nature of excitons in two-dimensional semiconductors. In contrast to the more phenomenological few-level approaches typically employed for modelling MDCS, our theory features mobile excitons with continuous momentum degrees of freedom. We find that the energy continuum associated with exciton momenta is crucial for producing interaction-induced decoherence, as well as capturing the interference between different exciton-polaron quasiparticles in the case of charge-doped semiconductors. Crucially, our calculated MDCS spectra agree well with recent experiments on doped monolayer MoSe$ _2$ [Hao et al., Nature Communications 8, 15552 (2017)], and they suggest that the interactions between exciton polarons depend strongly on phase-space filling effects, where exciton polarons compete for electrons. Our results demonstrate that microscopic approaches allow one to gain new insights from the fine structure of MDCS on two-dimensional semiconductors, and they illustrate the utility of microscopic approaches to modelling MDCS experiments more generally.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Gases (cond-mat.quant-gas), Optics (physics.optics)
22 pages, 13 figures
Shape Evolution and Dynamics of Deformable Ring
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-08-31 20:00 EDT
Arun Kumar, Partha Sarathi Mondal, Pritha Dolai, Shradha Mishra
We numerically investigate the dynamics of a deformable closed ring filled with active particles. The ring is modeled as a flexible boundary made up of passive beads interacting with a harmonic spring force. The interior of the ring is filled with active Brownian particles (ABPs), and their activity is controlled through the rotational diffusion coefficient. We explore how, by systematically varying the activity of ABPs, packing fraction, and size of the ring, we can control the shape deformation and dynamics of the ring. At low packing fractions, low rotational diffusion coefficients, and smaller ring sizes, the ring exhibits highly irregular and strongly deformed shapes due to the uneven spatial arrangement of active particles along the boundary. Increasing the packing fraction, rotational diffusion coefficient, or ring size promotes a more even distribution of active particles within the ring, thereby suppressing shape deformations and fluctuations, driving the ring toward a more circular shape. We further analyze the mean-squared displacement (MSD) of the ring’s center of mass and observe a crossover from ballistic to diffusive dynamics, which can be tuned by varying the system parameters. Our results demonstrate that, despite its internal complexity and deformability, the ring exhibits emergent behavior analogous to that of a single effective active particle. This study provides insight into the collective effects of confined active matter and the resulting macroscopic dynamics of deformable systems.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech), Biological Physics (physics.bio-ph)
13 pages, 8 figures
Significant modulation of acoustoelectric current associated with charge density wave transitions
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-31 20:00 EDT
Natsumi Nikaido, Takuya Kawada, Koji Fujiwara, Jihoon Park, Nan Jiang, Kouta Kondou, Shintaro Takada, Yasuhiro Niimi
We studied acoustoelectric (AE) currents in materials that undergo charge density wave (CDW) transitions, induced by a surface acoustic wave (SAW) on a piezoelectric substrate. The polarity and magnitude of the AE current in NbSe$ _3$ and 2H-TaSe$ _2$ were modulated due to their CDW transitions. We also found that the sign of the AE current depends on the SAW propagation direction with respect to the crystalline axis of the substrate.A phenomenological model assuming strain-modified conductivity can qualitatively account for the significant modulation of the AE current associated with the CDW transition, as well as the SAW propagation orientation dependence. The present results offer a powerful probe for exploring SAW-electron interactions in van der Waals materials, thereby highlighting their potential for advancing the emerging field of straintronics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
14 pages, 12 figures
How a polymer filling enhances the rate and selectivity of colloid permeation across mesopores
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-08-31 20:00 EDT
Mikhail Y. Laktionov, Frans A. M. Leermakers, Ralf P. Richter, Leonid I. Klushin, Oleg V. Borisov
Polymer-functionalised mesopores are an emerging technology for colloid separation, sensing and delivery. Their potential is strikingly illustrated in living cells, where nuclear pore complexes (NPCs) control biocolloid transport between the nucleus and the cytosol. Even colloids much smaller than the biopolymer-filled NPC channel are effectively blocked, but some larger colloids with distinct surface features rapidly permeate. Simplistically, one may expect any polymer filling to obstruct and slow down colloid transport. We demonstrate how a polymer filling that attracts colloids and extends beyond the mesopore, thus maximizing colloid capture, can instead increase permeation compared to a bare pore. We also define how polymer-filled mesopores can effectively gate colloids according to their size and surface features. Our findings provide a basic physical explanation for the exquisite permselectivity of NPCs, and a rational design strategy for novel mesopore-based separation, sensing, catalysis and drug delivery devices with enhanced performance features.
Soft Condensed Matter (cond-mat.soft), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph), Biomolecules (q-bio.BM)
Correlated disorder versus correlated noise: Ordering in active systems
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-08-31 20:00 EDT
Can quenched disorder generate ordering in driven systems? Using a recently proposed hydrodynamic model, we show that sufficiently long-ranged quenched disorder can induce long-range order in two-dimensional (2D) nonreciprocal XY systems, even when the clean system exhibits only short-range order at finite noise. Active surfaces tangentially advected by quenched velocities, governed by the same hydrodynamic equation, become statistically flat with super- or subdiffusive relaxation. In three dimensions (3D), quenched disorder combined with nonreciprocity produces a novel transition between strong-coupling and asymptotically noninteracting regimes, supporting either long- or short-range order. In both 2D and 3D, the exponents are nonuniversal, which vary continuously with the degree of transversality of the quenched disorder. The degree of transversality of the quenched disorder can be tuned to induce transitions in the model for fixed disorder and noise variances.
Statistical Mechanics (cond-mat.stat-mech)
6 pages, 3 figures (preliminary version)
Sound propagation in one-dimensional quantum droplets
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-08-31 20:00 EDT
Zizhou Yuan, Jiarui Xiao, Xiao-Long Chen
Sound propagation in quantum droplets differs from that in conventional Bose-Einstein condensates (BECs) because of their self-bound nature and the role of quantum fluctuations. We investigate sound propagation in one-dimensional quantum droplets formed by a symmetric Bose-Bose mixture, focusing on finite-size and confinement effects. Using the extended Gross-Pitaevskii equation, we extract the sound velocity from the real-time propagation of localized density perturbations and compare it with the low-energy excitation spectrum. We find that, unlike in a conventional BEC, the sound velocity of a finite droplet is strongly affected by its density profile and quantum-pressure contribution. It decreases with increasing particle number as the droplet evolves from a Gaussian-like to a flat-top profile, approaching the bulk quantum-droplet value. In contrast, external harmonic confinement compresses the droplet and enhances the sound velocity, driving the system toward the acoustic behavior of a trapped BEC. Our results establish sound propagation as a sensitive probe of finite-size effects and the crossover between self-bound quantum droplets and conventional Bose gases, and suggest a feasible route for experimental observation in ultracold $ ^{39}$ K droplets.
Quantum Gases (cond-mat.quant-gas)
11 pages, 6 figures
Mechanics and statistics of a solvable model of an autophoretic colloidal chain
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-08-31 20:00 EDT
Arvin Gopal Subramaniam, Rajesh Singh
Equilibrium statistical mechanics owes much of its analytical tractability to symmetry: detailed balance, gradient flows, and the resulting vanishing of steady-state entropy production follow directly from the structure of the underlying dynamics, not from any smallness of the driving. Exact solutions of this kind are rare away from equilibrium. Here we identify a class of far-from-equilibrium active colloidal chains – coupled via roto-translational, autophoretic (monopolar) interactions – that admit an exact quasi equilibrium description: at fixed chain geometry, the orientational equations of motion for every monomer are derivable from a scalar potential, detailed balance holds exactly in the orientational sector, while the positional sector breaks the equilibrium structure. The associated steady-state entropy production rate (EPR) vanishes identically for this sector, even though the full system is manifestly driven and dissipative. We solve this reduced dynamics exactly for dimers and semi-analytically for general $ N$ -mers, obtain the orientational fluctuations and the full-system EPR in closed form, and show that all dissipation is carried by the translational (center-of-mass) sector. We further examine the effect of dipolar chemical emission – expected from asymmetric micelle deposition at the monomer scale – and find that the equilibrium structure holds exactly for dimers, whereas for longer chains no such description is possible. A purely dipolar coupling instead producesa genuinely non-equilibrium state with no static attractor, sustaining non-monotonic drift with no fixed limit, and an EPR that itself never reaches steady state. Monopolar coupling remains necessary and sufficient for the polarized state; dipolar coupling alone breaks the quasi-equilibrium structure without replacing it with a new static one.
Soft Condensed Matter (cond-mat.soft)
Emergent aggregation from collective foraging
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-08-31 20:00 EDT
Gorka Muñoz-Gil, Andrea López-Incera, Vide Ramsten, Giovanni Volpe, Thomas Müller, Hans J. Briegel
Collective behaviour in living systems is usually modelled as the outcome of a \emph{direct} social drive: agents are rewarded, or hard-wired, to align with or approach their neighbours. Here we show that aggregation can instead emerge from an \emph{indirect} objective. We let reinforcement learning foragers, initially performing a random walk, optimize their dynamics from a purely individual reward for finding replenishable targets, while perceiving only their conspecifics and never the targets themselves. As the visual range grows, the agents undergo a sharp crossover from an environment-tuned individual search to a scale-agnostic collective one, and this crossover coincides with the onset of spatial aggregation. Thus a collective phase arises as a by-product of optimal foraging, without any direct reward for grouping. A minimal analytical first-passage model reproduces the transition as a crossover between the two search strategies. Our results identify indirect, resource-driven reward as a generic route to emergent collective phenomena.
Statistical Mechanics (cond-mat.stat-mech), Machine Learning (cs.LG), Multiagent Systems (cs.MA), Adaptation and Self-Organizing Systems (nlin.AO), Biological Physics (physics.bio-ph)
11 pages, 8 figures
Spin-Selective Spectral Flattening and Wave-Packet Dynamics in a Flux-Engineered Lieb Lattice
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-08-31 20:00 EDT
Nana Chang, Xiaoji Zhou, Yanglin Zhou, Song Ci
We investigate reversible internal-state-selective wave-packet transport induced by spin-dependent Peierls phases in a two-dimensional nearest-neighbor Lieb lattice. The two conserved spin components experience effective fluxes $ \alpha_{\sigma}=\alpha_{0}+s_{\sigma}\alpha_{s}$ , where $ s_{\uparrow,\downarrow}=\pm1$ . At the working point $ \alpha_{0}=\alpha_{s}=1/4$ , the spin-up and spin-down components experience $ \alpha_{\uparrow}=1/2$ and $ \alpha_{\downarrow}=0$ , respectively. A band-resolved calculation in the $ q=2$ magnetic unit cell shows that the spin-up spectrum contains two zero-energy flat subbands associated with the sublattice-imbalance flat-band sector, whereas the remaining four subbands retain finite bandwidths. The half-flux sector therefore fails the all-bands-flat condition and does not realize exact Aharonov–Bohm caging for a generic localized initial state. Nevertheless, real-time simulations reveal a pronounced suppression of spin-up propagation relative to the dispersive spin-down component, manifested by a smaller mean-square displacement and an enhanced finite-region retention probability over the pre-reflection time window. Reversing the state-dependent flux interchanges the slow and fast spin channels, while the dynamical contrast remains robust against moderate flux detuning. These results establish spin-dependent synthetic flux as a reversible means of controlling internal-state-resolved matter-wave transport without spin-flip processes or interactions, and provide complementary spectral and real-space criteria for distinguishing exact caging from finite-time dynamical slowing in atomic and photonic flat-band simulators.
Strongly Correlated Electrons (cond-mat.str-el)
14 pages, 5 figures
Weakly non-linear creep of amorphous polymers near their glass transition, comparisons between models and experiment
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-08-31 20:00 EDT
Martin Roman-Faure, Zhaocheng Zhang, Catalin Picu, Antoine Chateauminois, Francois Lequeux
The non-linear mechanics of amorphous polymers near the glass transition reveals a stress-induced acceleration of stress relaxation of nanometric sub-units. Recent theoretical work predicts that the local acceleration within these nano-domains should scale as the exponential of the squared local stress, a behavior now supported by experiments. However, this local dynamics has some complex consequences on the macroscopic mechanical response, as dynamical heterogeneities generate complex stress and strain fields in polymers close to the glass transition. In this study we consider the non-linear creep of an amorphous polymer near its glass transition and evaluate the relation between local and global acceleration and the emerging load-carrying structure, by comparing experimental data with predictions of three models of increasing complexity: a two-states (2S) model, a self-consistent (SC) model and a finite-element (FEM) model. The experimentally observed trend of accelerated creep under increasing applied stress is reproduced by the SC and FEM models, while the 2S model overestimates stress localization. The macroscopic, homogenized acceleration is predicted to be close to the microscopic one, albeit with an apparent yield stress that depends on compliance. The FEM model evidences the development of a load carrying sub-structure that occupies a small fraction of the total material volume driven by the interaction of sub-domains. This work shows that complexity and heterogeneity emerge due to non-linear interactions and that their adequate representation is essential for predicting the macroscopic mechanical response of amorphous polymers near their glass transition.
Soft Condensed Matter (cond-mat.soft)
Landau theory of quenched criticality in linear in-context learning
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-08-31 20:00 EDT
Daesik Kim, Sumin Choi, Hyojae Jeon, Jung Hoon Han
In-context learning (ICL) allows a pretrained model to infer a new task from examples supplied in its prompt without updating its parameters. In linear models of ICL, the prediction error develops a double-descent singularity when the number of pretraining samples becomes comparable to the number of learnable parameters. We formulate this interpolation singularity as a critical phenomenon of a quenched disordered system. By comparing annealed and quenched descriptions of the same linear ICL model, we identify the connected sample-to-sample fluctuations of the learned parameters as the microscopic origin of the singular error. A Landau potential is constructed by integrating the cavity self-consistency equation for the renormalized ridge parameter $ \xi$ . The role of (magnetization) order parameter is played by $ \xi$ , while the bare ridge parameter $ \lambda$ becomes its conjugate magnetic field. The normalized sample complexity $ \tau$ acts as a temperature and the double-descent singularity occurs at the critical temperature $ \tau_c =1$ . The Landau susceptibility is precisely the quantity that diverges in the fluctuation contribution to the prediction error. The order parameter is closely related to the fraction of zero eigenvalues of the empirical relaxation matrix in the ridgeless limit, which define flat directions in the learning dynamics. The Landau theory is generically cubic in the order parameter with critical exponents $ (\beta_{\rm cr},\delta_{\rm cr},\gamma_{\rm cr})=(1,2,1)$ . In the large-context regime, there appears a pseudogap-like regime characterized by suppressed order parameter. Predictions of the Landau theory are independently confirmed from numerical solutions of the original learning problem with good quantitative agreement. Our results pave the way for solid statistical-physics understanding of the interpolation criticality in linear in-context learning.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Machine Learning (cs.LG)
17 pages, 7 figures (counting subfigures)
uMOF: A Universal Database, Benchmark, and Machine Learning Interatomic Potentials for Metal-Organic Frameworks
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-31 20:00 EDT
Théo Jaffrelot Inizan (1,2), Prathami Divakar Kamath (1,3), Alin Marin Elena (4), Kristin A. Persson (1,3) ((1) Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA, (2) Bakar Institute of Digital Materials for the Planet, Division of Computing, Data Science, and Society, University of California, Berkeley, CA, USA, (3) Department of Materials Science & Engineering, University of California, Berkeley, CA, USA, (4) Scientific Computing Department, Science and Technology Facilities Council, Daresbury Laboratory, UK)
Foundation machine learning interatomic potentials (MLIPs) deliver near-ab-initio accuracy at a fraction of the computational cost, yet their promise for Metal-organic Frameworks (MOFs) remains largely unrealized as large unit cells make first-principles training data expensive to generate, fine-tuned models are scarce, and experimentally grounded benchmarks are scarcer still. We introduce uMOF, a three-part contribution addressing this gap. First, we release the largest and most accurate density functional theory dataset for MOFs to date, computed at the r$ ^2$ SCAN-D4 level of theory across 85524 configurations spanning 19950 unique frameworks and 79 elements, covering empty and gas-loaded structures, geometry optimizations, equations of state, and finite-temperature molecular dynamics. Second, we release a literature-mined benchmark of 3986 verified property values (3146 experimental) extracted from 626 papers by a seven-stage, checkpointed multi-pass large language model pipeline, linked to more than 650 crystallographic information files. Third, we release two universal MLIPs for MOFs, uMOF-MH and uMOF-POLAR, fine-tuned from two architecturally distinct MACE foundation models on the uMOF dataset. On near-equilibrium, ``Tier-1’’ properties (bulk modulus, phonon-derived heat capacity) the uMOF models perform comparably to existing foundation and fine-tuned baselines. On harder, dynamics-sensitive properties like gas adsorption enthalpies via Widom insertion and adsorption isotherms, the uMOF models outperform every baseline we test, including MOF-specialized gas-capture models trained on datasets up to three orders of magnitude larger, cutting error by more than 80% to within experimental uncertainty. We trace this advantage to the physical diversity of the training data and to level of theory where a small (1.7%) fraction of MD simulations is decisive for MLIP stability.
Materials Science (cond-mat.mtrl-sci)
19 pages, 5 figures, 7 tables
Band-like Carriers in a Soft, Anharmonic Lattice: Lead-Halide Perovskites
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-31 20:00 EDT
Young Mi Lee, Inhee Maeng, Jinwoo Park, Seung-Jae Oh, Min-Cherl Jung
Lead-halide perovskites APbX3 present a striking dichotomy: they exhibit band-like electronic transport despite their exceptionally soft and anharmonic lattices. Optically and electrically, they resemble conventional direct-gap semiconductors, exhibiting light carrier masses and steep absorption onsets, whereas their lattices display liquid-like dynamics, including overdamped octahedral motions, quasielastic Raman central peaks, and exceptionally low thermal conductivities. Solution-processed films nevertheless sustain micrometre-scale carrier diffusion at defect densities that would severely suppress transport in conventional semiconductors. Here, we argue that these apparently disparate properties emerge from a common microscopic framework: a soft, strongly anharmonic, and polar [PbX3]- framework, strongly influenced by the Pb 6s2 lone pair, which simultaneously shapes the antibonding orbital character of the band edges, the magnitude and multiple timescales of the dielectric response, and the slow relaxational dynamics that dress every charge carrier. We therefore invert the conventional order and develop the lattice before the electronic structure, because the nominally cubic phase is better viewed as a thermally fluctuating ensemble of locally symmetry-broken configurations rather than a single geometry. Within this framework, we discuss excitons, Frohlich large polarons in the intermediate-coupling regime, carrier transport, defect tolerance, dimensional reduction in two-dimensional and nanocrystalline derivatives, and symmetry-breaking phenomena. We critically assess three contested issues - defect tolerance, ferroelectricity, and the interpretation of the T-3/2 mobility law - and identify seven open questions together with the key measurements needed to resolve them
Materials Science (cond-mat.mtrl-sci)
54 pages, 20 figures, 3 tables
Charge transfer and competing symmetry breaking drive orbital reconstruction and emergent ferromagnetism in insulating oxide superlattices
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-31 20:00 EDT
Nandana Bhattacharya, Ranjan Kumar Patel, Siddharth Kumar, Sourav Chowdhury, Manav Beniwal, Suresh Chandra Joshi, Prithwijit Mandal, Jayjit Kumar Dey, Weibin Li, Manuel Valvidares, Zhan Zhang, Hua Zhou, Andrei Gloskovskii, Christoph Schlueter, Christoph Klewe, Srimanta Middey
Electron correlation, hopping, and ligand-to-metal charge transfer collectively lead to diverse electronic and magnetic phenomena in 3$ d$ transition-metal oxides, where directional d orbitals make hopping highly sensitive to symmetry-dependent orbital overlap. Heterostructure engineering with atomically flat interfaces adds symmetry-breaking charge transfer as a further route to emergent behavior, yet whether interfacial mismatch between constituent oxides of a superlattice shapes ground states independent of epitaxial strain remains unresolved. Here we examine superlattices combining NdNiO$ _3$ with Mott-insulating NdMnO$ _3$ . Varying layer thickness and combining transport with X-ray spectroscopy, we show that electron transfer from NdMnO$ _3$ to NdNiO$ _3$ drives a room-temperature insulating state with a distinct electronic structure, accompanied by a reversal in orbital symmetry beyond simple strain considerations, underscoring the interface’s central role. These reconstructions stabilize an emergent ferromagnetic insulating state arising from interfacial Ni$ ^{2+}$ -O-Mn$ ^{4+}$ superexchange. Our results establish a pathway to interface-engineered ferromagnetic insulating phases via competing interactions, with potential for spin-insulatronic applications.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
5 figures, 12 pages
Geometry-Controlled Dynamic Tensiometry Resolves Intrinsic Surfactant Adsorption Kinetics
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-08-31 20:00 EDT
Camille Brigodiot, Boxin Deng, Christine Dalmazzone, Karin Schroën, Annie Colin
At short times, interfacial tension depends on experimental geometry because surfactant transport to the interface depends on the mass-transfer conditions.A predictive description therefore requires more than a dynamic tension curve or a fitted adsorption constant: interfacial thermodynamics, diffusion, and adsorption kinetics must be identified separately. Here, we combine equilibrium and diffusion measurements with a microfluidic EDGE tensiometer that provides a nearly stationary interface and controlled micrometer-scale transport. Equilibrium properties and diffusion are determined independently, leaving adsorption kinetics as the key unknown. Dynamic tension is then calculated using a nonequilibrium thermodynamic description, without assuming instantaneous equilibrium between the adsorbed layer and the subsurface solution. For the nonionic surfactant C$ _{10}$ E$ _{8}$ , equilibrium thermodynamics and transport are independently constrained, and a single intrinsic adsorption rate constant describes several concentrations. We extend the framework to SDS by including electrostatic interactions and subsurface-concentration dynamics, capturing transient depletion and replenishment. Once thermodynamic, transport, and kinetic parameters are identified, the model predicts dynamic interfacial tension beyond the geometry and conditions used to determine them. The microfluidic EDGE tensiometer thus provides both a reliable short-time tensiometry method and a quantitative framework for identifying the physical mechanisms governing surfactant mass transfer at interfaces.
Soft Condensed Matter (cond-mat.soft), Chemical Physics (physics.chem-ph)
Field-tuned quasiparticles and electronic structure in heavy-fermion YbNi4P2
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-08-31 20:00 EDT
Will Broad, Owen Moulding, Takaki Muramatsu, Manuel Brando, Alix McCollam, Femke Bangman, Gertrud Zwicknagl, Kristin Kliemt, Cornelius Krellner, Sven Friedemann
We study the Fermi surface topology and quasiparticle properties in the heavy fermion compound YbNi4P2 at high magnetic fields using quantum oscillation measurements. We observe a large decrease of the quasiparticle mass with increasing field and demonstrate good qualitative agreement with the single-ion Kondo model. At the putative Lifshitz transition at 17 T, we observe a sudden change of quantum oscillation frequencies suggesting an abrupt change of the electronic structure and/or quasiparticle characteristics. Our results demonstrate the ability to tune the electronic structure and provide input for theoretical models of YbNi4P2 and correlated electron systems in high magnetic fields.
Strongly Correlated Electrons (cond-mat.str-el)
16 pages including SI
Light-induced atomic motion in ionic crystals
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-31 20:00 EDT
Jacob C. Warming, Simon P. S. Jessen, Emma A. Husted, Jan Thøgersen, Stefan Gundacker, Brian Julsgaard, Peter Balling, Rosana M. Turtos
Atomic motion in solids is conventionally driven by elastic collisions between ionizing particles and atoms, which transfer momentum and induce lattice displacements. In this work, we demonstrate a different mechanism for atomic displacement based on optical excitation of scintillating ionic crystals. Ionic crystals are unique systems because of the closed-shell electronic configuration of their constituent ions. In these materials, excitation above the band gap generates a hole that strongly distorts the lattice, resulting in the formation of a self-trapped hole (STH). The STH is Coulomb-attracted to the electron, thereby forming a self-trapped exciton (STE). Here, we demonstrate that in BaF2 - one of the fastest scintillators - the STE structure promotes the formation of long-lived electron and hole traps that persist in the lattice at room temperature. Such trapped electron-hole pairs occupy vacancy-interstitial fluorine pair positions, and can be created indiscernibly using optical or ionizing radiation excitation, as long as the STH is formed. Further, we demonstrate that it is possible to control the defect evolution with light. Selective optical stimulation of the trapped electrons or holes enables the regeneration of the STE at later times. This light-controlled defect engineering allows us to increase the yield of the STE signal appearing as optically stimulated luminescence (OSL) and to image the spatial distribution of the initial energy deposition, holding strong potential for ionizing-radiation detection. These findings provide a common framework underlying scintillation and OSL in ionic crystals of the fluorite structure, allowing for optical manipulation of atomic vacancies-interstitial pairs in similar systems.
Materials Science (cond-mat.mtrl-sci)
Topological signatures in the curvature-induced energy response
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-31 20:00 EDT
Jaehyeok Lee, Iuegyun Hong, Jinhong Park
Relativistic effective field theory predicts a topological energy response to a gravitational field that appears at third order in spatial gradients. Here, we investigate how this response emerges in the nonrelativistic Haldane model using a microscopic lattice formulation of curvature-induced deformations. We find that the leading first-order energy response is nonuniversal and depends on the bond-resolved structure of the deformation; in particular, it vanishes for a symmetric modulation of the three nearest-neighbor hoppings. In contrast, the third-order response exhibits a discontinuity across the topological transition whose magnitude agrees with the relativistic gravitational Chern–Simons prediction. Thus, although the absolute response is nonuniversal, its third-order discontinuity is universal and retains a characteristic topological fingerprint beyond the relativistic limit.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
17 pages, 6 figures
Proximity to Jamming Governs Acoustic Attenuation in Damped Packings
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-08-31 20:00 EDT
Colton Kawamura, Derek R. Olson, Anthony P. Austin, Joshua A. Dijksman, Brian P. Tighe, Abram H. Clark
We use particle-based numerical simulations to address a longstanding question regarding the origins of the linear frequency dependence of attenuation in fluid-saturated granular media. We study both the acoustic modes and wave propagation in damped, disordered particle packings. We calculate the damped vibrational modes of packings as a function of frequency, pressure, and grain-contact dissipation. The spatial structure and dissipation of these modes show a clear transition at a pressure-dependent critical frequency from viscous-like continuum behavior to more localized, scattering modes. We also measure how wavespeed and spatial attenuation rate depend on these same parameters. At the same critical frequency, wave propagation also shifts from coherent motion, where attenuation scales quadratically with frequency and linearly with contact damping, to much more incoherent particle-scale motion, where attenuation scales linearly with frequency and sublinearly with contact damping. All of these features, including the transition frequency, are consistent with a large collection of experimental data, which has not been explained by any framework based on grain-scale physics. We refer to this approach as ``Jammed-Network Scattering’’ (JNS), and propose it as a grain-scale framework for understanding the acoustics of fluid-saturated granular media.
Soft Condensed Matter (cond-mat.soft)
15 pages, 10 figures
Quantum thermodynamics near the border of a one-dimensional Bose gas
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-08-31 20:00 EDT
We consider an ultracold Bose gas in a half-open potential well, otherwise confined to a quasi-one-dimensional geometry. The Bogoliubov equations for its elementary excitations are solved in the continuous spectrum to explore the particle and energy content near the edge of the gas, beyond the often applied local density approximation. In particular, gradients in the condensate density enhance density-dominated excitations in the border region. We discuss excess (missing) particles and their energy by comparing to suitable reference solutions for quasi-homogeneous systems. The density profile near the edge shows no Friedel oscillations, but a dipolar feature from the spill-out of thermally excited particles. The calculations are performed in the grand-canonical ensemble and in the thermodynamic limit.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
12 pages, 10 figures, submitted to special issue of J. Chem. Phys. in memoriam Rudolf Podgornik
Two-dimensional quantum Griffith singularity in three-dimensional ZrN$_x$ superconducting films
New Submission | Superconductivity (cond-mat.supr-con) | 2026-08-31 20:00 EDT
Zi-Yan Han, Li-Min Yu, Yu-Cheng Cong, Yang Yang, Zhi-Xiang Sun, Zhi-Qing Li
We report the experimental observation of two-dimensional (2D) quantum Griffiths singularity (QGS) in $ \sim$ 200-nm-thick epitaxial ZrN$ _x$ superconducting films. The films possess a rock-salt structure and are three-dimensional (3D) with respect to superconductivity. For each film with $ x \gtrsim 1.30$ , the low-temperature magnetoresistance isotherms under fields perpendicular and parallel to the film plane cross over at a broad magnetic field range independently rather than at a single crossing point. Despite the macroscopic 3D nature of the superconductivity, the magnetoresistance isotherms at selected adjacent temperatures follow the theoretical prediction of power-law scaling for 2D superconducting systems, rather than that for 3D systems. The effective critical exponent $ z\nu$ , obtained by analyzing the magnetoresistance isotherms using the 2D power-law scaling, increases with decreasing temperature and diverges as the quantum phase transition is approached. In addition, the resistivity data near the superconductor-insulator or superconductor-metal transitions obey an activated scaling form that describes the quantum phase transition of 2D superconducting systems governed by an infinite-randomness critical point. The QGS in the ZrN$ _x$ films is attributed to quenched disorder induced by intrinsic defects, such as Zr vacancies and N interstitials, which creates spatially inhomogeneous superconducting rare regions. The dynamics of these rare regions, which may exhibit effective 2D characteristics near the quantum critical point, dominate the transport properties of the system near the quantum phase transition. Our results provide compelling evidence for the existence of QGS in 3D superconductors and highlight the crucial role of disorder-induced inhomogeneity in determining the critical behavior of quantum phase transitions.
Superconductivity (cond-mat.supr-con)
10 pages and 8 figures
Quantum Geometric Origin of Nonlinear Current Induced Orbital Magnetization
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-31 20:00 EDT
Xue-Jin Zhang, Yue-Xin Huang, Wei Du, Xiaolong Feng, Shen Lai, Cong Xiao, Qian Niu, Shengyuan A. Yang
Electric generation of magnetization is a focus of condensed matter research, and has recently been advanced into the nonlinear regime. However, due to the nonlocal nature of orbital magnetism, how to properly formulate nonlinear current-induced orbital magnetization remains a fundamental challenge. Here, we develop the proper theory for this effect. This is based on the microscopic derivation of field-corrected orbital magnetic moment of a Bloch electron, a critical missing piece in the present theory. We show that the quantum geometric origin of this phenomenon lies in both the anomalous orbital polarizability and the Berry-connection polarizability, which often provide competing contributions. Combining our theory with first-principles calculations, we predict significant, experimentally accessible nonlinear orbital magnetization generated in strained bilayer graphene, monolayer 1T’ $ \mathrm{MoS_2}$ and $ \mathrm{MoTe_2}$ . Remarkably, nonlinear orbital magnetization can dominate over its spin counterpart in materials with topological band features, irrespective of the spin-orbit coupling strength.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Interplay between crystal structure and magnetism in CeCrB$_4$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-31 20:00 EDT
Mirosław Werwiński, Andrzej Szajek, Andrzej Kowalczyk
CeCrB$ 4$ belongs to the family of MTB$ 4$ ternary metal borides, some of whose magnetic phases have recently been identified as quantum spin dimers. Employing density functional theory within the GGA+$ U$ framework, this work investigates the key ground-state properties of this system, including its ferromagnetic ground state, the mixed-valence nature of cerium, and the charge transfer from the cationic cerium–chromium layers to the anionic boron layers. In particular, we focus on elucidating the bonding mechanism within the structurally embedded Cr-Cr dimers. Specifically, we evaluate a previously proposed interpretation that the localized Cr $ 3d{z^2}$ states are molecular-like bonding and antibonding states. The calculated dependence of the $ 3d{z^2}$ electronic structure on the intra-dimer distance correlates with the level-splitting characteristics known for classical homonuclear diatomic molecules.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el), Computational Physics (physics.comp-ph)
9 pages, 5 figures
QUBO-Compatible Active Learning for Inverse Design of High-Entropy Alloys
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-31 20:00 EDT
Giorgio Silvi, Kirsten Bark, Rolando Reiner, Nicolas Vogt, Thomas Plehn, Daniel Barragan-Yani, Marc Landmann, David Melching
Machine-learned forward models can rapidly predict alloy properties, but their use for inverse design remains challenging when the search should also retain compatibility with quadratic unconstrained binary optimization (QUBO). Here, we develop a QUBO-compatible active-learning framework for inverse design of high-entropy alloys using a pretrained graph-neural-network predictor as a fixed property oracle. A property-guided binary variational autoencoder provides a binary latent representation, while an ensemble of quadratic factorization machines guides candidate selection. We systematically benchmark the framework through controlled latent-space ablations and comparison with direct composition-space optimization. The results show that candidate generation is a major determinant of search performance: local perturbations around previously high-performing latent codes provide the largest workflow-specific improvement, while surrogate-based selection further prioritizes candidates within the enriched search pool. The resulting QUBO-compatible workflow remains competitive with strong classical optimization strategies, although a composition-space genetic algorithm achieves the highest mean score. Finally, the learned quadratic surrogate can be exported directly as a QUBO. These results show that effective data acquisition can be separated from the final QUBO optimization endpoint, providing a benchmarked route for QUBO-compatible data-driven materials inverse design.
Materials Science (cond-mat.mtrl-sci)
Rapid Charge Stability Diagram Generation from Device-level Modeling of Semiconductor Quantum Dots
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-31 20:00 EDT
Ron Nodel, David W. Kanaar, Connor Nasseraddin, Tim J. Wilson, Hong-Wen Jiang, Jason R. Petta, Chris Anderson, Mark F. Gyure
Self-consistent Schrödinger-Poisson calculations are a powerful tool for predicting the behavior of layered semiconductor quantum dot devices. However, characterization of charge stability diagrams through fully simulated gate-voltage sweeps is computationally expensive. Combining a Multi-Domain Multi-Model (MDMM) approach with an automated tuning routine, we identify gate voltages associated with selected charge configurations. This small set of self-consistent simulations can be augmented with Full Configuration Interaction (FCI) energy calculations to extract charging energies, lever arms, and interdot Coulomb interactions to directly parameterize a Hubbard model for rapid charge stability diagram generation. For an Intel Tunnel Falls Si/SiGe device, we demonstrate the Hubbard model’s ability to reproduce charge stability diagrams at a fraction of the computational cost in comparison to voltage bias sweeps. We further compare the simulated diagrams to experimental data and demonstrate qualitative agreement. Our result represents a step towards predictive digital twin models for semiconductor quantum dot devices. Finally, we apply this workflow towards lever arm engineering in a second device, demonstrating that the method extends to multiple architectures.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
15 pages, 9 figures
Nanolamellar Hybrid High-Entropy Alloys with Superior Micromechanical Properties
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-31 20:00 EDT
Shivam Dangwal, Yoji Mine, Shohei Ueki, Xavier Sauvage, Fabien Cuvilly, Liliana Romero Resendiz, Muhammad Naeem, Kaveh Edalati
Metallic materials with nanolamellar structures, such as pearlitic steels, exhibit high strength with appropriate ductility. Considering the potential ability of such nanolamellar structures to break the traditional strength-ductility trade-off in metallic alloys, this study aims at developing a unique nanolamellar structure with superior micromechanical properties by combining two different high-entropy alloys (HEAs). Al0.1CoCrFeNi with the face-centered cubic (FCC) structure is combined with TiZrHfNbTa with the body-centered cubic (BCC) structure using high-pressure torsion (HPT) of half discs of each alloy. That way, a layered hybrid structure was formed, with layer thickness down to about 61 nm. The BCC/FCC nanolamellar hybrid structure exhibits an exceptional combination of properties with an ultimate tensile strength of 2.4 GPa, a maximum bending strength of 4.0 GPa, and a hardness of 740 Hv, while retaining some ductility/plasticity under both tensile and bending loads. Detailed analyses by synchrotron diffraction, electron microscopy and atom probe tomography suggests that these high strength and hardness, which are superior to those of nanostructured HEAs, result from: (i) extreme grain boundary strengthening from nanograins with a mean size of 22 nm, (ii) presence of defects such as dislocations in FCC and BCC, stacking faults in FCC and twins in FCC, and (iii) interphase hardening from BCC/FCC nanolamellar boundaries with about 30% contribution to the total hardness. This work demonstrates that combining two HEAs using HPT into a defect-rich hybrid nanolamellar composite forms a promising synergy of ultrahigh strength and reasonable ductility/plasticity.
Materials Science (cond-mat.mtrl-sci)
Phenomenological Growth Regimes in Liquid-Precursor CVD of MoS$_2$ on Functional Substrates
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-31 20:00 EDT
Osamah Kharsah, Kilian Mouchel, Yossarian Liebsch, Cathy Sulaiman, Joel Verlande, Anke Hierzenberger, Abdallah Alghazali, Clara Grygiel, Stéphane Guillous, Henning Lebius, Marika Schleberger
The integration of two-dimensional transition-metal dichalcogenides (TMDCs) onto functional substrates remains constrained by stochastic vapor-phase growth dynamics. Here, we show that liquid-phase precursor chemical vapor deposition (CVD) of MoS$ _2$ introduces growth conditions that are consistent with a substrate-influenced reaction-diffusion process. By utilizing pre-growth spin-coated MoO$ _3$ intermediates across a diverse crystalline library (sapphire, SrTiO$ _3$ , rutile TiO$ _2$ , MgO, and 6H-SiC), we find that substrate-dependent variations in precursor wetting, surface chemistry, and inferred mass-transport constraints correlate with distinct growth morphologies.
These substrate-dependent growth regimes are interpreted in terms of reduced effective lateral growth length on SrTiO$ _3$ , possible precursor anchoring on TiO$ _2$ , likely chemical surface restructuring on MgO, and possible step-edge growth on SiC. Raman and photoluminescence spectroscopy reveal substrate-dependent variations in vibrational and optical response that correlate with differences in strain, charge environment, and dielectric screening. Ultimately, this work highlights a substrate-dependent reaction-diffusion framework as a potentially useful route for tuning the structural and optical properties of large-area 2D materials.
Materials Science (cond-mat.mtrl-sci)
9 pages, 3 figures
A Generalized Model for Disordered Random Sequential Adsorption with Charge-Dependent Deposition
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-08-31 20:00 EDT
We generalize a one-dimensional random sequential adsorption model (RSA) of charged unit segments in which the deposition position follows a beta kernel determined by the charges bounding the available gap and those of the incoming particle. The interaction parameter (0\leq\lambda<1) interpolates between uniform car parking and strongly localized deposition. We derive a four component generating function equation that provides exact recursions for the complete occupation statistics, although only the mean and variance are analyzed in detail here. Exact finite-shell solutions serve as benchmarks for the Gauss–Jacobi quadrature and Monte Carlo simulations. We prove that, although boundary charges affect finite size behavior, the four boundary states have the same asymptotic mean and variance densities, consequently, we prove that the jammed density is self-averaging. Numerical results show that charge selectivity increases the coverage, especially for mixtures dominated by opposite endpoint charges, which also exhibit strongly reduced fluctuations near (\lambda=1). The model provides a tractable connection between uniform RSA, dynamically generated disorder, and interaction-driven deposition.
Statistical Mechanics (cond-mat.stat-mech)
Nucleation and propagation of brittle fracture as a constrained energy minimization problem
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-31 20:00 EDT
Oscar Lopez-Pamies, Farhad Kamarei, Gilles A. Francfort, Alessandro Giacomini
This paper presents a macroscopic, or continuum, theory aimed at describing when, where, and why cracks nucleate and propagate in nominally elastic brittle materials under monotonic, quasi-static, but otherwise arbitrary mechanical loads. Motivated by recent insights, the proposed sharp theory posits that: \emph{cracks nucleate and propagate exclusively in regions where the strength surface of the material is exceeded, with their evolution dictated by the minimization of the sum of the potential — the elastic energy minus the work done by the externally applied forces — and surface energies.} While the theory applies to materials with any elasticity (linear or nonlinear) and any material symmetry (isotropic or anisotropic), attention is restricted here to the most basic case of isotropic elastic brittle materials. For demonstration purposes, the theory is confronted with a set of nine tests that span the entire range of well-settled experimental knowledge on fracture nucleation and propagation — the so-called ``Nine Circles of Elastic Brittle Fracture’’ — on both a hard material (a silicate glass) and a soft material (a synthetic rubber).
Materials Science (cond-mat.mtrl-sci), Mathematical Physics (math-ph)
Evidence for Three-component Interlayer Coherent Exciton Condensation
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-31 20:00 EDT
Subi Du, Xiaohan Zhang, Hongxi Song, Siyu Fan, Yiduo Wang, Zhenyu Wang, Song Liu, Kenji Watanabe, Takashi Taniguchi, Jiangping Hu, Yang Xu
Increasing the number of internal components in a quantum many-body system can host collective orders inaccessible to simpler settings. Quantum Hall bilayers provide a canonical realization of interlayer exciton condensation, yet extending such coherence across three independently addressable electronic fluids has remained elusive. Here we report evidence for three-component interlayer coherent exciton condensation in triple-layer graphene system. Using Rydberg excitons in an adjacent WSe2 monolayer as a layer-sensitive optical probe, we resolve interaction-induced incompressibility at zeroth-Landau-level crossings for all three pairwise layer combinations, establishing top-middle, middle-bottom and top-bottom exciton condensate channels within the same device. Independent control of displacement field and interlayer bias continuously tunes these pairwise states towards a regime where Landau levels from all three layers approach simultaneous degeneracy. At their convergence, incompressibility persists while the exciton energy and spectral weight evolve smoothly between the pairwise limits, suggesting coherent participation of all three layers in a single three-component state. More broadly, the ability to independently control layer potentials and engineer interlayer interactions establishes multilayer graphene as a programmable synthetic dimension for exploring higher-component quantum Hall order and simulating strongly correlated quantum matter.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
22 pages and 4 figures
Work Function and High-Coverage Adsorption Energy as Hydrogen-Evolution Descriptors on Ag-Au-Pd-Pt Alloys
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-31 20:00 EDT
Zacharias Liasi, Ridha Zerdoumi, Felix Thelen, Geovane Arruda de Oliveira, Rico Zehl, Natalia Pukhareva, Leonardo H. Morais, Henrik H. Kristoffersen, Alfred Ludwig, Wolfgang Schuhmann, Jan Rossmeisl
Hydrogen-evolution activity is commonly rationalized through hydrogen adsorption energies and the Sabatier principle, yet this descriptor picture becomes ambiguous on multimetallic surfaces, where each composition exposes a distribution of local adsorption environments. Here we investigate whether the bare-surface work function, previously shown to add predictive information for monometallic surfaces, remains an activity descriptor for compositionally complex surfaces. We test this on three combinatorial Ag-Au-Pd-Pt thin-film materials libraries screened for acidic hydrogen evolution by scanning electrochemical cell microscopy. Graph neural networks provide adsorption-energy distributions and work functions for each measured composition. A work-function-only model explained most of the activity variation (mean $ R^2_\mathrm{log}$ = 0.903), as did a coverage-corrected adsorption model (mean $ R^2_\mathrm{log}$ = 0.955), outperforming dilute adsorption (mean $ R^2_\mathrm{log}$ = 0.758). Combining work function and coverage-corrected adsorption yielded the highest fit quality (mean $ R^2_\mathrm{log}$ = 0.969), but only a small gain over coverage-corrected adsorption alone. For these four metals the coverage-corrected adsorption energy and work function follow a similar trend, producing similar activity rankings, hence including both adds little beyond either one individually, although both are strong predictors.
Materials Science (cond-mat.mtrl-sci)
26 pages, 11 figures
Crystal-phase quantum dots in AlGaAs nanowires
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-31 20:00 EDT
Rohan Radhakrishnan, Rodion Reznik, Gilles Patriarche, Lorenzo Leandro, Igor Ilkiv, Anna Andreeva, Artem Khrebtov, George Cirlin, Nika Akopian
Crystal-phase quantum dots (CPQDs)$ \unicode{x2014}$ quantum dots in nanowires defined by crystal structure rather than material composition$ \unicode{x2014}$ constitute the only platform capable of fabricating quantum-dot arrays with the ultimate precision of a single atomic layer. This intrinsic control yields perfectly aligned quantum dots with atomically sharp interfaces, providing a unique pathway toward scalable quantum-dot-based photonic quantum technologies. To date, CPQDs have been studied primarily in binary semiconductors, such as InP and GaAs, where their emission linewidths are typically in the meV range, thereby limiting their technological potential. Here, we report, for the first time, CPQDs in AlGaAs nanowires and show bright single-photon emission with linewidths as narrow as 61 $ \mu eV$ and low background emission, demonstrating optical quality well beyond typical CPQDs. We attribute this performance to a type-I band alignment, as suggested by an exciton lifetime of 1 ns, significantly shorter than that typically observed in type-II CPQDs. Additionally, we observe an exciton fine-structure splitting and a Zeeman splitting, as commonly observed in standard type-I self-assembled quantum dots.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics), Quantum Physics (quant-ph)
Main text: 18 pages, 4 figures / Supplementary Materials: 8 pages, 3 figures
Topological Signatures of Hardness and Structural Order in Network-Forming Materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-31 20:00 EDT
Yair Augusto Gutiérrez Fosado, Ayobami Daramola, Davide Marenduzzo, Ciprian G. Pruteanu
Understanding how the topology of network forming materials influences their physical properties remains a longstanding challenge. Here, we investigate the topology of experimentally compatible atomistic models of amorphous silica together with the crystalline polymorphs cristobalite and quartz. By comparing multiple atomistic models of amorphous silica that equally reproduce neutron-scattering data, we show that different microscopic descriptions can imply different topological interpretations of glass stability. To characterize the network beyond conventional geometric descriptors, we introduce the linking valence, which quantifies the average number of topological links per network loop. This topological descriptor separates silica into two distinct classes: the mechanically harder quartz exhibit values more than an order of magnitude larger than those of amorphous silica and cristobalite, despite their common tetrahedral building blocks. Spectral analysis of the loop-linking networks provides a complementary distinction, separating amorphous from crystalline phases and revealing differences in the long-range organization of topological constraints. These results establish topological linking as a new framework for connecting the structure and physical properties of network-forming materials.
Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
Nonholonomic collective flows: velocity–orientation locking in a continuum with microstructure
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-08-31 20:00 EDT
We develop a continuum theory for a fluid of elongated particles that advance along their own axes. The same kinematics is ideally shared by flocks of sheep, self-propelled rods, vehicular traffic, and turning flocks of birds. Within the framework of continua with vectorial microstructure, in which each point also carries an orientation, we impose the no-side-slip (skate) condition $ \vv=u,\nn$ as an ideal, non-integrable internal constraint. We derive the pure equations of motion and the equation governing the constraint reaction from the principle of virtual power. Using a constitutive closure provided by the Ericksen-Leslie theory of nematic liquid crystals, we show how the constraint also shapes collective effects. It turns parabolic orientational diffusion into hyperbolic orientation-density waves and forbids any steady simple shear. It fixes the empirical Toner-Tu convective coefficient to the flow-alignment ratio measured in colloidal rollers, thereby providing a mechanical foundation for angular sound in micropolar active hydrodynamics. It also recovers the inertial spin model of bird flocks, with the addition of a banking force and a turn-density coupling. Finally, it recovers the classical macroscopic models of one-dimensional traffic flow, while describing steering, lateral tyre forces, and road geometry in two dimensions.
Soft Condensed Matter (cond-mat.soft), Mathematical Physics (math-ph)
Electrically Tunable Two-Component Exciton Condensate in a Coulomb-Coupled Graphene Trilayer
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-31 20:00 EDT
Bo Zou, A. Okounkova, Shuaiqing Zhang, Jian Liao, J. Pack, K. Watanabe, T. Taniguchi, Yihang Zeng
Multicomponent condensates possess internal phase degrees of freedom unavailable to a single-component condensate, yet their components are rarely controllable in solids. Here we realize a graphene trilayer with negligible interlayer tunnelling in which the layer-specific carrier densities are continuously tuned by electrostatic gating. Quantum-capacitance measurements demonstrate that charge-incompressible quantum Hall states at total filling factors 1 and 2 persist across the full range of layer-filling configurations and continuously connect the three bilayer exciton-condensate limits. This persistence provides evidence for a trilayer excitonic state. Static Hartree-Fock and time-dependent Hartree-Fock calculations yield two independent finite phase-stiffness eigenmodes and two linearly dispersing Goldstone modes, respectively, when all three layers are partially filled, whereas only one phase-stiffness eigenmode and one linear Goldstone mode remain when one layer is unfilled. The stiffness eigenmodes rotate continuously between the two adjacent-layer exciton bases as charge is transferred among the layers, revealing electrical control of the condensate-mode composition. Together, the experimental and theoretical results support the identification of a two-component exciton condensate with a continuously tunable internal structure.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Quantum transport and unified scaling law in graphene with polyadic Cantor electrostatic barriers
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-31 20:00 EDT
Sudhanshu Shekhar, Mohammad Umar, Bhabani Prasad Mandal
We study the quantum transport of Dirac electrons in graphene subjected to a polyadic Cantor-structured electrostatic potential. Using the superperiodic potential formalism, we obtain a closed-form expression for the transmission probability. As the Cantor stage increases, the transmission spectrum evolves from a sparse set of superlattice resonances to a near-transparent regime, with the polyadic order setting the rate of this evolution. The angular response depends on the doping configuration, showing distinct behavior in the $ n$ –$ n$ –$ n$ , $ n$ –$ p$ –$ n$ , and Dirac-point cases. In the near-transparent regime, the transmission follows double-logarithmic scaling laws with respect to four independent control parameters: the Cantor stage, the potential height, the initiator length, and the angle of incidence. By combining these individual scaling relations, we establish a unified scaling law governing quantum transport. These results show that the hierarchical self-similarity of the potential governs the transport properties of such systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), High Energy Physics - Theory (hep-th), Mathematical Physics (math-ph), Quantum Physics (quant-ph)
18 pages, 11 figures
Magnonic Combinatorial Memory based on a network of coupled active ring circuits
New Submission | Other Condensed Matter (cond-mat.other) | 2026-08-31 20:00 EDT
Mykhaylo Balinskiy, Paulo Julio, Jeffrey Vargas, Diana Bisono Balaguer, Jacob Greenstein, Alexander Khitun
Magnonic Combinatorial Memory (MCM) is a type of memory where the bits of information are encoded in the signal propagation paths in the network. In this work, we consider MCM based on the network of a coupled active ring circuit (ARC). Each circuit includes a broadband amplifier, a magnonic delay line, an adjustable frequency filter, an adjustable phase shifter, and a power detector. The coupling between the circuits is via spin waves propagating in the common delay line - ferrite film. There may or may not be auto-oscillations in the active ring circuits, depending on the combination of circuit parameters and circuit coupling. The address of MCM is defined as the combination of the states of the phase shifters and frequency filters, while the MCM state is defined as the presence/absence of the auto-oscillations. The coupling between the circuits is achieved by placing micromagnets on top of the ferrite film. The number of bits that can be encoded in the network increases quadratically with the number of coupled circuits. This scaling provides a fundamental advantage over conventional memory. We present experimental data obtained for three magnonic ARCs connected via a single-crystal yttrium iron garnet Y3Fe2(FeO4)3 (YIG) film. The data illustrate an example of encoding a 27-bit binary response pattern, corresponding to the 27 experimentally accessible phase combinations. The results demonstrate a robust operation of MCM with an On/Off ratio exceeding 30 dB at room temperature. The advantages and shortcomings of the proposed approach are discussed.
Other Condensed Matter (cond-mat.other)
ScatterWorks: A Python package for building and solving scattering network models
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-31 20:00 EDT
R. Johanna Zijderveld, Hélène Spring, Anton R. Akhmerov
Network models provide an efficient framework for studying non-interacting transport and wave-propagation phenomena in disordered and topological systems. We introduce ScatterWorks, an open-source Python package for building and solving network models. The package uses a compact network representation with composable transformation operations (tile, cut, relink, and union) to enable flexible construction of periodic and finite networks. Local scattering matrices on nodes can be assigned by node labels or explicit indexing, assembled into global scattering equations, and used to compute quasienergies and transport observables. The package supports sparse scattering matrices, allowing transport observables to be evaluated with Schur-based solvers. We demonstrate the package workflow on a symbolic Fabry-Perot interferometer and a numerical Chalker-Coddington model, recovering analytical expressions and the expected near-critical transport behavior of the quantum Hall transition. Plotting utilities with label-aware rendering are included to streamline debugging and reproducible setup for larger, custom network geometries.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
16 pages, 5 figures
Gauge invariance, collective modes, and the justification of normal-state subtraction in Dirac superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2026-08-31 20:00 EDT
In Dirac superconductors, the unbounded spectrum of low-energy Dirac models is known to give rise to unphysical interband contributions from deep-lying states to the electromagnetic response. To eliminate these contributions, normal-state subtraction (NSS), in which the normal-state response is subtracted from the superconducting-state response, has been widely employed. However, the relation between NSS and a gauge-invariant electromagnetic response, particularly the role of the vertex correction required by the Ward identity, has remained unclear. In this work, we consider a massive-Dirac model with $ s$ -wave pairing and analytically investigate the electromagnetic response at zero temperature by solving the Bethe–Salpeter equation and incorporating the collective-mode contribution to the electromagnetic vertex. We show that, in the static long-wavelength limit, the vertex correction exactly cancels the bare longitudinal response with NSS, yielding the vanishing longitudinal response required by gauge invariance. In contrast, the transverse component of the vertex correction vanishes in the long-wavelength limit, so that the gauge-invariant Meissner weight coincides with that obtained from the bare transverse response with NSS. Moreover, within the class of isotropic and analytic UV regularization terms, we show that gauge invariance uniquely fixes the regularization term in the static long-wavelength limit to the value prescribed by NSS. Our results thus provide a microscopic justification for NSS.
Superconductivity (cond-mat.supr-con)
14 pages, no figures
Wyckoff-Resolved Oxidation-State Atlas and Anion-Conditioned Priors for Materials Discovery
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-31 20:00 EDT
We introduce a Wyckoff-resolved oxidation-state atlas and assignment utility for probabilityranked, charge-neutral assignment from compositions or Wyckoff grammars. The atlas is constructed from a May 2026 snapshot of 154,879 Materials Project-derived structures by staged exact-neutral enumeration over common and known nonzero oxidation states. The learned prior assigns 106,053 materials in composition mode and 114,403 in Wyckoff mode, compared with a broad MP all-integer possible species count of 108,642. A matched MP baseline requiring at least one charge-neutral assignment with exactly one nonzero integer oxidation state per element contains 89,374 materials; relative to this baseline, composition and Wyckoff modes increase coverage by 18.7% and 28.0%. Of the 14,665 materials recovered only in Wyckoff mode, 99.98% exhibit distinct formal oxidation states for the same element on different site tokens. The CSV/Python workflow provides a reproducible prior for structure decoration, generative crystal models, and symbolic Wyckoff-grammar workflows.
Materials Science (cond-mat.mtrl-sci)
19 pages (main & SI) and 5 figures
Automated Dislocation Detection in Electron Channelling Contrast Imaging: A Comparative Study of Rule-Based, Neural Network, and Deep Learning Approaches
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-31 20:00 EDT
A. Holmes, C. Trager-Cowan, J. Bruckbauer, B. Hourahine
Quantifying threading dislocations in semiconductor materials via electron channelling contrast imaging (ECCI) is heavily bottlenecked by slow manual analysis. This work benchmarks three automated detection pipelines on ECCI micrographs of gallium nitride (GaN) against a statistical ground truth. A classical rule-based computer vision approach proved unreliable due to extensive per-image tuning requirements, while a convolutional neural network (CNN)-based multi-stage classification and locator method achieved 87% accuracy but required significant time for a test image and was less efficient in high-density regions. By contrast, a unified single-stage you only look once (YOLOv8) architecture achieved a counting accuracy of 98.6%, alongside 98.7% precision and 98.7% recall across 7451 dislocations over multiple images, with rapid inference times. Successful deployment of YOLOv8 required addressing two domain-specific machine learning challenges. First, to mitigate the model’s scale sensitivity, an adaptive gaussian tile-sizing algorithm was developed to optimise the field of view per image. Second, the deployed confidence threshold (0.025) differed substantially from the suggested inference default value for YOLOv8 (0.25), raising counting accuracy from 90.8% to 99.3% on a subsection of the benchmark image. In this case, low confidence scores represented physical signal strength rather than classification ambiguity. This unified, scale-adaptive approach demonstrates practical viability for high-throughput, quantitative semiconductor defect characterisation.
Materials Science (cond-mat.mtrl-sci)
31 pages, 9 figures, 5 tables
Modifying van der Waals Materials via Cavity Vacuum Fluctuations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-31 20:00 EDT
Mohammad Hassan, Cankut Tasci, Leonardo A. Cunha, Johannes Flick
In the field of cavity quantum materials, vacuum fluctuations of optical cavities are used for modifying ground-state properties of quantum materials without external driving. Here, one example is the van der Waals (vdW)/dispersion interaction in layered 2D vdW materials, where non-additive long-range correlations can dominate the interlayer binding. While cavity-induced changes of such interactions have been predicted and described using ab initio methods for molecular systems, no efficient description exists yet for extended materials. In this Letter, we close this gap by introducing a periodic formulation of the photon many-body dispersion (pMBD) functional within quantum electrodynamical density-functional theory (QEDFT). Applying this method with efficient $ \textbf{q}$ -point sampling to bilayer hBN and graphene, we predict cavity-modified stacking, increased equilibrium interlayer distances, and softened layer breathing modes with increasing light-matter coupling strength. Our results establish cavity vacuum fluctuations as a tuning knob for the structural properties of vdW materials.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph), Optics (physics.optics), Quantum Physics (quant-ph)
6 pages, 2 figures
Hierarchical organization governs nonlinear mechanical reversibility in $ι$-carrageenan gels
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-08-31 20:00 EDT
Carrageenan gels are thermoreversible polysaccharide networks whose mechanical properties emerge from ion-mediated helix association, yet how their molecular organization controls nonlinear deformation remains poorly understood. Here, we investigate the temperature-dependent rheology of $ \iota$ -carrageenan gels formed in KCl solutions using linear and nonlinear oscillatory rheology combined with normal-force measurements. $ \iota$ -carrageenan forms homogeneous and mechanically reversible gels whose elastic modulus increases continuously with quench depth. Deep quenches generate pronounced strain stiffening before yielding, associated with the development of internal stresses revealed by negative normal forces. Remarkably, large deformations preserve the small-strain elastic modulus while progressively suppressing strain stiffening, demonstrating a partial mechanical reversibility of the network. We interpret these observations using a hierarchical network picture in which a persistent intermolecular network controls linear elasticity, while a more fragile mesoscale organization enables cooperative alignment and stress amplification under deformation. Our results highlight that nonlinear mechanics of thermoreversible polysaccharide gels are governed not only by molecular connectivity, but also by the reversible formation and eventually destruction of mechanically adaptive hierarchical structures.
Soft Condensed Matter (cond-mat.soft)
Switchable chiral antiferromagnetism through nonlinear magnetic susceptibility
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-31 20:00 EDT
Antiferromagnets (AFM) have attracted considerable attention in recent years because a number of nontrivial, technologically relevant properties associated with time-reversal symmetry (TRS) breaking are discovered in many materials. However, time-reversal (TR) partners of AFM states are generally challenging to be selected deterministically except in a few cases with nonzero net magnetization. Recently, it has been shown that the TR partners of the kagome spin ice ground state in HoAgGe with strictly zero net magnetization can be selected through a nonlinear magnetic susceptibility $ \chi^{(1)}$ . In this work, we generalize this scenario to a broad class of chiral AFM with zero net magnetization but field-switchable ground states through $ \chi^{(1)}$ . After a general discussion of $ \chi^{(1)}$ and its symmetry constraints, we first present a first-principles formalism for calculating it including both mean-field and self-consistent corrections, and then apply the approach to the noncollinear AFM family Mn$ 3X$ N ($ X=$ Ni, Ag, Ga, Zn, Sn) in the $ \Gamma{5g}$ phase. An intuitive picture of the origin of $ \chi^{(1)}$ in similar noncollinear AFM is illustrated using 3-sublattice toy model. The model also predicts a nontrivial temperature dependence of $ \chi^{(1)}$ due to competitions between the longitudinal and transverse single-spin susceptibilities. Our work shows that nonlinear susceptibility can serve as a general protocol for accessing and switching TR partners in fully compensated AFM.
Materials Science (cond-mat.mtrl-sci)
9 pages; supplemental material included in /anc
Machine learned designs of functional colloidal foldamers
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-08-31 20:00 EDT
Ryan van Mastrigt, Zorana Zeravcic
A protein’s function follows from the structure it adopts, and which structure that is depends on the pathway taken. In programmable matter the target is fixed before assembly, and whatever else forms is treated as error. Here we show that pathways themselves form a design space. Using reinforcement learning, we fold model DNA-coated droplet chains into rigid two-dimensional geometries, uncovering two classes of pathways: downhill, in which bonds are only added, and detour, in which bonds are broken and remade before the target is reached: for some the only route that exists. Coarse-graining pathways by interactions gives experimentally realizable protocols. Some produce one geometry, others several: structures sharing a detour route can be cycled between, while those that coexist assemble into superstructures inaccessible to a uniform product. Function emerges from the pathways rather than being designed. Designing the process instead of the components could give colloidal materials that reconfigure and repair themselves on demand.
Soft Condensed Matter (cond-mat.soft), Computational Physics (physics.comp-ph)
8 pages, 5 figures
A Three-Fluid Model of Dissipation at Surfaces in Superconducting Radiofrequency Cavities
New Submission | Superconductivity (cond-mat.supr-con) | 2026-08-31 20:00 EDT
Matthias Liepe Michelle M. Kelley, Sean Deyo, Nathan Sitaraman, Danilo B. Liarte, Tomás Arias, James P. Sethna, Thomas Oseroff
Experiments on superconducting cavities have found that under large RF fields the quality factor can improve with increasing field amplitude, a so-called anti-Q slope.'' We numerically solve the Bogoliubov-de Gennes equations at a superconducting surface in a parallel magnetic field, finding at large fields there are surface quasiparticle states with energies below the bulk superconducting gap that emerge and disappear as the field cycles. Modifying the standard two-fluid model, we introduce a three’’-fluid model where we partition the normal fluid to consider continuum and surface quasiparticle states separately. We compute dissipation in a semi-classical theory of conductivity, where we provide physical estimates of elastic scattering times of Bogoliubov quasiparticles with point-like impurities having potential strengths informed from complementary \textit{ab initio} calculations of impurities in bulk niobium. We show, in this simple yet effective framework, how the relative scattering rates of surface and continuum quasiparticle states can play a role in producing an anti-Q slope while demonstrating how this model naturally includes a mechanism for turning the anti-Q slope on and off.
Superconductivity (cond-mat.supr-con), Accelerator Physics (physics.acc-ph), Computational Physics (physics.comp-ph)
8 pages, 7 figures
Super-resolution Control of Two-dimensional Quantum Emitters
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-31 20:00 EDT
Bosai Lyu, Valeria Vento, Ludivine Fausten, Daniel Suarez-Forero, Klevis Domi, Kenji Watanabe, Takashi Taniguchi, Alberto Morpurgo, Iaroslav Gaponenko, Patrycja Paruch, Ajit Srivastava
Localized interlayer excitons in semiconducting transition-metal dichalcogenide heterobilayers are quantum emitters with a static electric dipole moment, making them excellent nanoscale charge sensors to probe correlated quantum phases in a proximal layer. These emitters are electrically tunable and inherit spin-valley selection rules, yet their deterministic spatial control remains challenging due to subwavelength confinement. Here, we present a platform that combines cryogenic optical spectroscopy with scanning probe microscopy to investigate trapped interlayer excitons in WSe$ _2$ /MoSe$ _2$ bilayers. By exploiting AFM-based local Stark shift, we achieve super-resolution localization of emitters separated by only a few tens of nanometers and demonstrate deterministic control of individual charge states, including trion formation, opening a path towards coherent inter-dot coupling. Time-resolved measurements reveal tip-induced modification of the electromagnetic vacuum around individual emitters, thus controlling their radiative emission. Our multi-point charge sensing platform with optical readout is particularly well-suited to study fractionalization and anyon dynamics in semiconducting FCIs.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Solvable relaxation in discrete unitary systems: Ruelle-Pollicott resonances and CMV matrices
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-08-31 20:00 EDT
Urban Duh, Friedrich Hübner, Marko Žnidarič
Leading eigenvalues of the truncated propagator, known as Ruelle-Pollicott (RP) resonances, are an elegant way of addressing the dynamics of unitary many-body systems. We study unitary propagators in their canonical form, known in the mathematical literature as the CMV matrices, and obtain a number of exact results for RP resonances and the associated norm-diverging eigenvectors. For the simplest CMV class describing a unilateral shift with an impurity, motivated by operator dynamics in dual-unitary circuits, we obtain closed-form results and in particular show that the three independent ways of obtaining RP resonances – the truncated propagator, analytic continuation of the resolvent, and the rigged Hilbert space approach – all give the same results. In more realistic CMV matrices, in which shift-like operator dynamics characteristic of chaotic systems is only asymptotic, we rely on the rich theory of orthogonal polynomials on the unit circle and identify two phases. In the first phase, relaxation occurs due to local operators effectively evolving into increasingly nonlocal ones with negligible backflow. Especially interesting is the second phase, which, surprisingly, exhibits faster relaxation because of contributions from the backflow of large operators. Additionally, in the second phase, RP resonances are not equal to the eigenvalues of the truncated propagator, instead, they are ``hidden’’ within a ring of ill-conditioned eigenvalues.
Statistical Mechanics (cond-mat.stat-mech), Mathematical Physics (math-ph), Chaotic Dynamics (nlin.CD), Quantum Physics (quant-ph)
33+12 pages
Layer-Controlled Intermolecular Coupling and Many-Body Effects in C$_{60}$ Films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-31 20:00 EDT
Hai-Lan Luo, Weitang Li, Luca Moreschini, Jonathan Denlinger, Zhigang Shuai, Claudia Ojeda-Aristizabal, Alessandra Lanzara
Crystalline C$ _{60}$ is a molecular solid whose electronic properties emerge from the interplay of intermolecular hopping, electron correlations, and electron-vibration coupling. Unlike moir$ \rm\acute{e}$ van der Waals heterostructures, where interaction strength is commonly tuned by twist angle, molecular materials offer a complementary route in which layer number, molecular orientation, and substrate registry provide experimentally accessible control parameters. Here we present a systematic thickness-dependent angle-resolved photoemission study of C$ _{60}$ films, spanning the monolayer to the bulk limit. The HOMO-derived band exhibits a non-monotonic evolution: the intermediate-thickness film shows larger bandwidth, reduced effective mass, and pronounced gap-like and sub-band features. The experimental trends, together with Holstein-model simulations, point to strengthened effective intermolecular electronic coupling and enhanced electron-phonon-induced spectral renormalization in the intermediate-thickness regime. These results identify a dimensional crossover in C$ _{60}$ films and establish layer number as an effective knob for engineering electronic structure and many-body interactions in molecular thin films.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
10 pages, 4 figures; accepted for publication in Nano Letters
Interaction corrections to topological density three-point functions in two-dimensional Fermi liquids: a coadjoint orbit perspective
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-08-31 20:00 EDT
Akshay Pal, Andrew Lucas, Umang Mehta
Density three-point correlations are known to probe the topology of the Fermi sea in two-dimensional noninteracting systems. Here, we study how these correlations are modified by interactions using the coadjoint-orbit effective field theory. A key advantage of the coadjoint-orbit formulation is that it provides a systematic way to incorporate generalized Landau interactions in terms of bosonized degrees of freedom, mapping fermionic loop contributions onto simpler tree-level diagrams. We show that, for a general isotropic dispersion $ \epsilon(p)$ , even at linear order in the generalized Landau interaction, $ \mathcal{O}(\mathcal{F}^{(2,0)})$ , there exists a contribution proportional to the band curvature $ \epsilon’’(p_F)$ that changes the nonanalytic structure of the free density three-point correlation function.
This contribution introduces a distinct nonanalytic structure beyond that found in either the noninteracting case or an interacting Galilean-invariant system, showing that interaction effects can modify the topology-detecting density three-point correlation.
Strongly Correlated Electrons (cond-mat.str-el)
24 pages, 1 figure
Research Square
Resonant Water Splitting via Acoustic Phonon Coupling: Overpotential Minimization and Clean Thermal Combustion
Physical Sciences - Article | Chemical physics | 2026-08-30 20:00 EDT
Min Ho Jung
Conventional water electrolysis faces thermodynamic overpotentials and significant energy penalties (285.8 kJ/mol), hindering scalable zero-carbon hydrogen and thermal energy generation. Here, we demonstrate an acoustic phonon-coupled resonant water-splitting mechanism operating across a 40 kHz to 1 MHz standing wave field over a discrete Mersenne superlattice manifold (GF(M_127)). By inducing harmonic lattice excitation in liquid water without chemical additives, the activation energy barrier for molecular dissociation is significantly mitigated, enabling sustained oxyhydrogen combustion at flame temperatures exceeding 2,800°C with a >91.4% reduction in input electrical dissociation power penalties. High-speed optical, pyrometric, and quadrupole mass spectrometry diagnostics reveal sub-millisecond dissociation dynamics (0.458 ± 0.012 ms latency) under steady-state acoustic confinement. Complete condensation of the combustion effluent yields ultrapure liquid water (99.999% purity, BER = 0.00000), establishing a closed-loop zero-emission thermodynamic cycle. Protected under Korean Patent Application No. 10-2026-0160525 (Claiming Priority of No. 10-2026-0146291), this work provides a scalable mechanistic framework for low-energy aqueous dissociation and closed-loop zero-carbon thermal energy systems.
Research Square:rs-10846554 (2026)
Posted on Research Square
Physical sciences/Physics/Chemical physics, Physical sciences/Chemistry/Materials chemistry/Electronic materials
A Two-Dimensional Crystal of Strongly Interacting Superatoms
Physical Sciences - Article | Self-assembly | 2026-08-30 20:00 EDT
Gerd Duscher, Austin Houston, Wolfgang Windl, Sumner Harris, Daniel Yimam, Ivan Vlassiouk, David Geohegan, Kai Xiao
Superatoms are discrete molecular clusters exhibiting collective electronic states resembling elemental atoms. To date, most two-dimensional (2D) crystals assembled from superatoms are weakly interacting, meaning building blocks rely on surfactants or van der Waals interactions to avoid decomposition into collections of elemental atoms. Here we demonstrate that superatoms can bond in a covalent fashion in two dimensions, forming a strongly interacting superatomic crystal, thereby extending the effective periodic table. The superatoms, identified as Pd<6>Se<20> and Pd<6>Se<21> distorted cubes, are shown to bond strongly in a lattice and host electronic band structures with discrete energy levels, like atoms. Due to their large effective masses of 2218 and 2297~amu, their motion during 2D crystal assembly can be directly observed by electron microscopy. The resulting superatomic crystal exhibits the full hierarchy of crystalline defects, including vacancies, dislocations, and grain boundaries, analogous to those found in conventional atomic solids. We propose that the superatoms are useful for studying the early stages of nucleation and growth of atomic crystals by analogizing the superatoms to elemental atoms.
Research Square:rs-10666935 (2026)
Posted on Research Square and Under Review at Nature Portfolio
Physical sciences/Materials science/Soft materials/Self-assembly, Physical sciences/Materials science/Nanoscale materials/Molecular self-assembly, Physical sciences/Materials science/Nanoscale materials/Two-dimensional materials, Physical sciences/Materials science/Nanoscale materials/Synthesis and processing