CMP Journal 2026-10-12
Statistics
Nature: 1
Nature Physics: 2
arXiv: 71
Research Square: 1
Nature
Antiviral immunity via telomerase-like reverse transcription in bacteria
Original Paper | Non-coding RNAs | 2026-10-11 20:00 EDT
Stephen Tang, Josephine L. Ramirez, Qixiang He, Mario Rodríguez Mestre, Tanner Wiegand, Dennis J. Zhang, Megan Wang, George D. Lampe, Jing Wang, Yanzhe Ma, Marko Jovanovic, Rafael Pinilla-Redondo, Israel S. Fernández, Samuel H. Sternberg
Defense-associated reverse transcriptases (DRTs) employ diverse and distinctive mechanisms of cDNA synthesis to protect bacteria against viral infection1. However, the functions and mechanisms of many DRTs remain unknown2. Here we identify a new antiviral defense system, DRT10, that associates with a noncoding RNA (ncRNA) to catalyze processive, protein-primed synthesis of tandem-repeat DNA. Reverse transcription is templated by a defined ncRNA region with a characteristic sequence pattern and template boundary elements, both of which are conserved and essential for DNA repeat addition. Cryo-EM reconstructions reveal an unanticipated 2:1 architecture, wherein two RT monomers bind opposite sides of a pseudo-symmetric ncRNA. Biochemical experiments further demonstrate that each RT monomer reverse transcribes the template encoded on its respective side of the ncRNA, but only one generates the long repetitive product, whose template is defined by the distance between two flanking stem-loop anchors. This mode of iterative, boundary-delimited cDNA synthesis exhibits direct parallels to the mechanism of telomeric repeat addition by eukaryotic telomerase, and phylogenetic analyses of RTs across domains of life place telomerase in a monophyletic clade with the DRT family, suggesting a common origin for their DNA polymerization activities. Together with earlier studies of DRT2, DRT3, and DRT93-5, our findings identify a conserved mechanistic logic underlying RNA-templated DNA repeat addition across diverse DRTs, despite vastly different architectural solutions, and expand the repertoire of reverse transcription-based strategies for antiviral immunity in bacteria.
Non-coding RNAs, Phage biology, Molecular evolution, Cryoelectron microscopy
Nature Physics
Morphogenesis of a stratified cell mound at a vortex defect
Original Paper | Biological physics | 2026-10-11 20:00 EDT
Hsiang-Ying Chen, Carles Blanch-Mercader, Caroline Giuglaris, Jacques Prost, Pascal Silberzan
Topological defects in cell monolayers have been recognized as mechanical organizing centres in morphogenetic processes. However, the mechanism by which cells coordinate their motion at such defects and self-organize into higher order structures remains elusive. Here we describe the formation of three-dimensional multicellular mounds in unconfined myoblast monolayers at well-controlled vortex topological defects. Before the onset of the formation of a bilayer, the vortex structure induces millimetre-scale cell flows that converge towards the defect centre. As a result, three-dimensional cell mounds form at the defect core, layer by layer. These mounds grow by interlayer permeation sustained by the converging cell flows. At late stages, the bell shape of the structured mounds can be modelled with dynamics driven by these converging flows. Our results highlight the crucial role of integer topological defects in driving large-scale cell flows that result in the formation of highly ordered three-dimensional tissues from a monolayer. We propose that similar mechanisms may be at play in certain morphogenetic and tumorigenic events.
Biological physics, Cellular motility
Chip-mediated manipulation of photonic quantum skyrmions
Original Paper | Quantum optics | 2026-10-11 20:00 EDT
Haoqi Zhao, Yichi Zhang, Isaac Nape, Shuang Wu, Yaoyang Ji, Chenjie Zhang, Yijie Shen, Andrew Forbes, Liang Feng
Quantum skyrmions are attracting much interest owing to their topological robustness, which offers a route to address noise and loss in quantum systems. The toolkit for their creation has advanced recently, enabling quantum skyrmions to be generated in bulk systems as entangled states and on chip as single-photon states. However, methods for generating on-chip entangled skyrmions, as well as for their reconfigurable manipulation and controlled interfacing with single-photon skyrmions, remain elusive. Here we demonstrate entangled skyrmions and their manipulation on chip with an integrated silicon nitride nanophotonic platform. The skyrmion topology is coherently encoded in a local single-photon spin-textured quantum state, which is subsequently transferred into a non-local skyrmion topology shared between two entangled photons. Throughout the transfer process, the topology remains preserved under background noise and different types of disturbance, even after the entanglement vanishes. This establishes a quantum-topology-enabled transfer scheme beyond entanglement, which reveals a fundamentally enhanced resilience that outperforms conventional entanglement-assisted quantum state transfer. This approach serves as a step towards building robust quantum interconnects and advancing distributed quantum information technology mediated by topology.
Quantum optics, Single photons and quantum effects
arXiv
Spinodal-controlled freeze-out and nucleation at the first-order superfluid-supersolid transition of a dipolar gas
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-10-12 20:00 EDT
Dipolar quantum gases in elongated traps become supersolid through a transition that is continuous at intermediate density but first order at low and high density; at the continuous point, ramps of the scattering length follow Kibble–Zurek scaling. We study ramps across the first-order superfluid–supersolid transition of $ ^{164}$ Dy in an infinite tube using the three-dimensional extended Gross–Pitaevskii equation with truncated-Wigner noise. With quantum noise only, the uniform superfluid survives the metastable window and transforms after its spinodal, where the roton softens. For onsets occurring during the linear ramp, the delay measured from this spinodal has a fitted exponent $ \zeta = 0.36 \pm 0.02$ , close to the continuous-transition result and the mean-field value $ 1/3$ . The quoted uncertainty combines statistical and systematic sensitivities. Reverse ramps show a comparable delay beyond the fold of the crystal branch, producing dynamical hysteresis. Initial thermal noise with nominal temperatures of 2.5–10 nK produces crystalline regions inside the metastable window during holds, with faster nucleation closer to the spinodal and at higher initial temperature. Without a heat bath these effective rates depend on preparation: ramps crossing the window at the same rate nucleate early in 2 of 32 or 11 of 16 realizations depending on their starting point. A crossover time inferred from hold rates is therefore an estimate, not a measured boundary for the ramp protocol. At low density, slower ramps select larger spacings in a crystal of separated droplets, and droplets survive far above the transition on reverse ramps.
Quantum Gases (cond-mat.quant-gas), Statistical Mechanics (cond-mat.stat-mech)
12 pages, 6 figures
Flat-band quantum geometry from embedded quench dynamics
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-10-12 20:00 EDT
Ilia Komissarov, Daniel E. Sheehy, Ahana Chakraborty
Quantum geometry underlies a wide range of correlated phenomena in electronic systems, yet accessing the geometry of individual bands remains experimentally challenging. Advances in quantum simulators, such as ultracold atoms in optical lattices, have enabled local state preparation and site-resolved measurements, offering direct access to quantum dynamics beyond conventional transport probes. These developments naturally raise the question of whether band-resolved quantum geometry can be extracted from local occupation readouts. Here, we propose an on-site quench protocol to probe the flat-band quantum geometry via local occupation measurements in an atomic lattice. Our scheme dynamically isolates the flat-band sector by coupling a one-dimensional flat-band lattice to a two-dimensional flat-band bath. The bath selectively removes dispersive excitations, while compact localized states remain trapped due to their overlap with the flat-band modes of the bath. We show that the late-time occupation pattern directly encodes the integrated overlaps between flat-band states separated by the wavevector of the initial density pattern, thereby enabling access to integrated quantum distances between the states separated by the commensurate momenta $ \delta k = 2 \pi s/r$ , $ s,r \in \mathbb Z$ and to the integrated flat-band quantum metric. Our results thereby establish a direct connection between quantum geometry and the long-time memory of an initial spatial pattern in flat-band systems.
Quantum Gases (cond-mat.quant-gas), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
10 pages, 5 figures
Frustrated Topological Orbital Magnetism
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-12 20:00 EDT
Sergio Garrido Bourkhaeva, Claudio Castelnovo, Wojciech J. Jankowski
By studying the interplay of geometric frustration with Aharonov-Bohm fluxes in three dimensions, we unveil a rich playground exhibiting topological semimetallic ground states with orbital magnetic dipole, quadrupole and ferrotoroidic orders, akin to spin patterns in classical spin ices - a class of phenomena which we dub frustrated topological orbital magnetism. We demonstrate that the ground-state toroidizations underpinned by non-Abelian topological nodal lines induce measurable current-induced Hall phenomena. We further find that distinct 2-in-2-out and 3-in-1-out frustrated orbital current patterns can be associated with topological Weyl node charges, and corresponding anisotropic linear and nonlinear Hall effects. We propose signatures for experimental validation of distinct frustrated topological orbital magnetic orders in candidate materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
13 pages, 8 figures
Enhanced Coulomb pseudopotentials in high-pressure hydrides from first principles
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-12 20:00 EDT
Kieran Bozier, Chris J. Pickard
In the Eliashberg theory of superconductivity, Coulomb interactions oppose the phonon-mediated attraction and suppress the superconducting critical temperature $ T_{\mathrm{c}}$ . However, most first-principles predictions continue to treat this repulsion with an empirical Coulomb pseudopotential $ \mu^\ast_{\text{ME}}$ in the range 0.1-0.15. Here we present first-principles calculations of the Coulomb parameter $ \mu$ and pseudopotential $ \mu^\ast_{\text{ME}}$ in superconducting hydrides across a range of pressures. The screened Coulomb interaction is evaluated at the random phase approximation level with the Mantel code. We demonstrate that several hydride systems, including H$ 3$ S, YSbH$ 6$ and Mg$ 2$ IrH$ 6$ , have strong Coulomb repulsions driven by a large density of states at the Fermi energy, $ N{\mathrm{F}}$ . For Mg$ 2$ IrH$ 6$ we obtain $ \mu=0.62$ and $ \mu^\ast{\text{ME}}\approx0.39$ , leading to a 40 K suppression in $ T{\mathrm{c}}$ relative to a standard $ \mu^\ast{\text{ME}}=0.16$ . Our obtained $ \mu^\ast{\text{ME}}$ is far above the conventional range and, accounting for the energy dependence of the density of states, resolves the factor-of-two discrepancy between $ T{\mathrm{c}}$ estimates of previous studies. Across all systems and pressures studied, we find that $ \mu$ closely tracks $ N_{\mathrm{F}}$ , suggesting that commonly used $ \mu^\ast_{\text{ME}}$ values lead to overestimated $ T_{\mathrm{c}}$ in materials where the density of states at the Fermi energy is large.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
13 pages, 7 figures
Odd-parity surface magnetism in a Kondo insulator
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-12 20:00 EDT
Maxim Dzero, Brian M. Andersen
We formulate a theory of spin-polarized tunneling between a nanowire tip of a topological Kondo insulator SmB$ _6$ and the bi-collinear antiferromagnet Fe$ _{1+x}$ Te in which the tunneling conductance which measures magnetic contrast changes sign when the bias is reversed. First we show that no time reversal symmetric tip, however strong its spin-momentum locking is, can produce experimentally observed magnetic contrast, which implies that time reversal must be broken at the tip surface. Within a mean-field treatment of the surface theory of SmB$ _6$ we find that the interaction between conduction d-and f-electrons drives a surface phase transition near T$ _c$ ~10 K in which the time reversal odd component of the Kondo hybridization amplitude condenses in the same symmetry channel as an out-of-plane surface magnetization, gapping out the Dirac surface states. Below the transition the spin-resolved spectral function of each gapped surface Dirac cone is odd in energy about its node. For a charge-neutral apex the Fermi level lies between the surface $ \Gamma$ and $ X$ Dirac nodes, so the spin-polarized conductance, which is determined by this function at the bias energy, reverses its sign close to zero bias. This sign change is thus a spectroscopic signature of time reversal symmetry breaking on the surface of SmB6.
Strongly Correlated Electrons (cond-mat.str-el)
17 pages, 8 figures
Entropic-ordered superfluid
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-12 20:00 EDT
We present a minimal classical lattice model of superfluidity at arbitrarily high temperatures, using a modified three-dimensional XY model with ``soft” rotors. The global U(1) symmetry is spontaneously broken above a positive critical temperature due to entropic order. We study hydrodynamics in this high-temperature regime and verify consistency with the fluctuation-dissipation theorem, explaining how the large noise variance at very high temperatures is not sufficient to destroy superfluidity or the long lifetime of Goldstone modes.
Statistical Mechanics (cond-mat.stat-mech)
Search for free non-Abelian anyons in paired composite-fermion states
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-12 20:00 EDT
The even-denominator fractional quantum Hall (FQH) states, understood as topological superconductors of composite fermions, are predicted to support elementary quasiparticles (QPs) or quasiholes (QHs) obeying non-Abelian braid statistics. Using the microscopic framework of parton theory, we investigate many experimentally observed paired composite-fermion states and find that their elementary QPs and QHs in general bind to form Abelian molecules, thus obscuring non-Abelian braid statistics. An exception is the $ \nu=1/2$ state in wide quantum wells, where our calculations show free QPs or QHs; we thus identify this state as an especially promising candidate for realizing and studying non-Abelian braid statistics. We also indicate how the study of such bound states can help reveal the topological structure of the state.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
16 pages, 2 figures in the main text, 6 figures in the supplementary material
Entropy Production in Mesoscopic Electronic Transport Beyond Weak-Coupling
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-12 20:00 EDT
Ivana R. A. C. Lucena, Caio H. Lewenkopf, Alexandre R. Rocha
We investigate the full statistics of entropy production in coherent mesoscopic conductors beyond the weak-coupling regime. Using the inside-outside perspective and the Landauer-Büttiker scattering framework, we relate entropy production to the full counting statistics of particle transport and show that the corresponding cumulant-generating function satisfies the fluctuation symmetry independently of the coupling strength. We obtain closed analytical expressions for the cumulant-generating function in the weak- and strong-coupling limits, enabling a detailed characterization of entropy production distributions and higher-order cumulants. These cumulants reveal distinct signatures of resonant transport and coherent fermionic partitioning. While coupling-induced broadening substantially modifies the transport statistics, the fluctuation symmetry imposed by microscopic reversibility remains preserved in the long-time limit.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Statistical Mechanics (cond-mat.stat-mech)
Spectral optimization of spherical lattices and applications to classical and quantum interacting spin systems
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-12 20:00 EDT
Jonas Völler, Grigorios Makris, Fabian Hassler, Stefan Wessel
We develop an optimization algorithm for spherical lattice discretizations based on the spectrum of the discretized Laplace operator. Starting from refined icosahedral lattices, we minimize the splitting of the $ (2\ell+1)$ , $ \ell=0,1,2,\dots$ , continuum multiplets expected from $ \mathrm{SO}(3)$ symmetry via gradient descent. This approach simultaneously produces lattices based on triangles with nearly uniform circumradii and perimeters. Although the optimization uses only the free-particle spectrum, we show that the resulting lattices carry over to interacting models. On the optimized lattices, rotational symmetry is restored for the critical Ising and Potts models and primary scaling dimensions are accurately reproduced for the three-dimensional Ising conformal field theory, when appropriate geometry-dependent interaction strengths are used. Higher-angular-momentum descendant states reveal weak residual symmetry breaking beyond the sectors protected by the underlying icosahedral symmetry.
Statistical Mechanics (cond-mat.stat-mech), Strongly Correlated Electrons (cond-mat.str-el)
30 pages, 18 figures, Submission to SciPost
Improving the lower bound on the Laughlin gap: An SDP search
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-12 20:00 EDT
A recent preprint by OpenAI resolved the spherical fermionic Laughlin spectral-gap conjecture for the full $ V_1$ interaction by a Fock-space inequality: $ H_Q^2\ge \gamma H_Q$ on the lowest-Landau-level Fock space for all large flux $ Q$ and every $ \gamma$ below $ 0.0461673\ldots$ , so that the gap above the Laughlin state at filling $ 1/3$ is at least $ 1/25$ . That proof, with its original constant, has also been formalized in Lean. We show that the same argument supports a much larger constant. Two sharper estimates, a product-twirl bound for the three-body tail and a staircase price for the four-body allowance, raise the constant above $ 0.0601$ without changing the original certificate. Treating the auxiliary operators as the variables of a semidefinite program (SDP) and enlarging the finite set of orbital modes on which they act then gives $ H_Q^2\ge\gamma H_Q$ for every $ \gamma<\gamma_\ast=0.2190037845063196\ldots$ , certified by exact rational arithmetic. Consequently the gap above the Laughlin state is at least $ 1/5$ for all sufficiently large spheres, and the untruncated planar $ V_1$ Hamiltonian has positive spectrum bounded below by $ \gamma_\ast$ , uniformly in particle number and angular momentum. A heuristic extrapolation of the SDP optima suggests that auxiliary operators of the present form can give at most about $ 0.222$ , while exact diagonalization of finite systems places the true gap near $ 0.4$ . A larger family of auxiliary operators could push the bound further towards the true gap, and the SDP formulation makes such families easy to test. The proof of the improvement and the SDP search were completed by the AI model Claude Opus 5.5 (Anthropic) under the author’s direction.
Strongly Correlated Electrons (cond-mat.str-el)
20 pages
Electron binding by charge disorder surrounding gapped bilayer graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-12 20:00 EDT
Jude McClay, Angelika Knothe, Igor Rozhansky, Vladimir Fal’ko
Bilayer graphene (BLG) is a unique electronic material offering electrostatic tunability of its band gap. Here, we study how charge disorder in the dielectric environment modifies band-edge states by binding electrons and holes to Coulomb centres, taking into account the in- and out-of-plane dielectric response of Bernal bilayers. We apply this framework to (a) hBN-encapsulated medium-size-gap BLG used for gate-defined quantum dots, and (b) BLG under double n/p ionic gating. In hBN/BLG/hBN, we find that single remote charges produce only weakly bound states, with binding energies generally small compared with the BLG gap. Under ionic gating, we find that the bound states are too large to be trapped by individual ions – localisation arises from fluctuations in the ion density, whose magnitude is limited by Coulomb charging energy at the freezing temperature $ T_f$ of the ionic configuration. Thus, in both regimes, charge disorder does not produce deep midgap states, with the bound states remaining closer to the conduction and valence band edges.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Homogeneous to multi-scale inhomogeneous complex magnetism in Ba3LnRu2O9 (Ln = Gd, Ho), Revealed by muSR and Machine-Learned Muon-Site Calculations
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-12 20:00 EDT
S. Ghosh, K. Sharma, E. Kushwaha, M. Kumar, G. Roy, A. Pandey, F. L. Pratt, S. Cottrell, D. T. Adroja, T. Basu
We report a comprehensive muon spin rotation and relaxation (muSR) study of the hexagonal 6H-perovskites Ba3LnRu2O9 (Ln = Gd, Ho) to investigate the role of rare-earth anisotropy in the magnetic ground state of 4d-4f coupled systems. Ba3HoRu2O9 exhibits two successive magnetic orderings at TN1 = 46 K and TN2 = 10 K, leading to a complex magnetic ground state, whereas Ba3GdRu2O9, with Gd3+ (L = 0) S-state ions, shows primarily single magnetic ordering at TN = 14.5 K. Zero-field (ZF) and longitudinal-field (LF) muSR measurements reveal markedly different magnetic behavior despite their structural similarity. Ba3HoRu2O9 displays a multi-scale inhomogeneous magnetic state characterized by two-component exponential relaxation, broad local-field distributions, incomplete LF decoupling, and persistent spin dynamics. The muSR results identify two characteristic magnetic energy scales near 46 and 10 K, associated with correlated Ru-Ho interactions and quasistatic magnetic ordering, respectively. Redfield analysis further demonstrates strong local magnetic fields and distributed spin fluctuation timescales, confirming magnetic inhomogeneity. Machine-learning-assisted muon-site and dipolar-field calculations show that the broad field distribution naturally arises from muons sensing distinct coexisting magnetic domains at different structural sites. In contrast, Ba3GdRu2O9 exhibits a comparatively homogeneous antiferromagnetic ground state below 14.5 K, with Gaussian relaxation consistent with a narrow static field distribution. These results establish that the rare-earth ion in Ba3LnRu2O9 is a powerful tuning parameter, driving the ground state from homogeneous to complex, multi-scale inhomogeneous behavior through competing 4d-4f magnetic interactions.
Strongly Correlated Electrons (cond-mat.str-el), Computational Physics (physics.comp-ph)
The quantum geometry of the chemical bond
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-12 20:00 EDT
Gabrielle Carrel, Nishchhal Verma, Fatmagül Katmer, Leslie M. Schoop, Raquel Queiroz
Electronic properties of materials depend both on band energies and quantum geometry of electronic states. We relate bonding indices to the quantum geometric tensor (QGT), showing how chemical bonding dictates the momentum-space texture of bands, bridging chemical and physical descriptions of solids. We show the QGT decomposed into the three center bond index, weighted by their oriented area. Resolving these contributions by orbital pair reveals the donor–acceptor character that distinguish ionic, covalent, hypervalent, and metavalent bonding. We identify the bonding pattern for topology in materials: noncollinear three center bonds, which are the source of Berry curvature in solids. Bond fluctuation can be directly linked to electromagnetic response by resolving their energy spectrum, opening a quantitative route towards the design of physical properties of materials from bonding motifs.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
30 pages, 6 figures, including Supplementary Material
Corrugated Niobene: Stability, Mechanical and Electronic Properties from First-Principles Calculations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-12 20:00 EDT
Willian O. Santos, José A. S. Laranjeira, Kleuton A. L. Lima, Douglas S. Galvão, David L. Azevedo
The growing diversity of two-dimensional (2D) materials has expanded opportunities in electronics, energy technologies, catalysis, and optical applications. Within this landscape, understanding how corrugated architectures accommodate metallic bonding and influence the stability and properties of monoelemental niobium sheets remains an open research direction. Here, we propose a corrugated niobene nanosheet, denoted c-Nb, and investigate its structural, energetic, vibrational, mechanical, electronic, and optical properties using density functional theory simulations. The optimized structure adopts a centrosymmetric P-3m1 symmetry, with six atoms per primitive cell and a geometrical thickness of 4.279 Angstrom. Its cohesive energy of -6.03 eV/atom indicates strong binding relative to isolated atoms, although bulk BCC Nb remains energetically favored by 2.49 eV/atom. The absence of imaginary phonon frequencies along the investigated high-symmetry path and the positive-definite in-plane stiffness matrix support dynamical and mechanical structural stability. Despite its pronounced corrugation, the nanosheet exhibits isotropic in-plane elasticity, with Young’s and shear moduli of 43.66 N/m and 13.66 N/m, respectively, and a Poisson’s ratio of 0.598. Electronic states near the Fermi level are dominated by Nb 4d orbitals, establishing multiband metallicity. These findings identify a corrugated structural candidate that combines strong cohesion, elastic compliance, and metallic electronic behavior, extending the structural diversity of monoelemental 2D metals and providing a basis for further exploration of niobium nanosheets in electronic and ultraviolet-responsive systems.
Materials Science (cond-mat.mtrl-sci)
12 pages, 6 figures
Nonlocal Josephson coupling and current redistribution in a large-area graphene multiterminal Josephson junction
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-12 20:00 EDT
Luojia Zhang, Kushagra Aggarwal, Jay D. Sau, Ethan G. Arnault, Kenji Watanabe, Takashi Taniguchi, Valla Fatemi
Multiterminal Josephson junctions (MTJJs) extend conventional two-terminal Josephson physics to devices defined by multiple superconducting phases, where rich phenomena have been predicted. However, in conventional MTJJs, superconducting transport is often dominated by local coupling between neighboring leads, obscuring physics that goes beyond simple connectivity. Here, we realize a multiterminal Josephson network in a graphene Hall bar geometry with micron-scale dimensions, enabling substantial nonlocal coupling between distant terminals. Our key observation is a pronounced negative differential longitudinal resistance (NDLR) in the four-probe response near switching currents, while no such feature appears in two-terminal measurements. We reproduce the NDLR response with a network containing the interplay between two distinct forms of nonlocality: nonlocal Josephson coupling, which determines the switching sequence of the superconducting network, and nonlocal normal-state conductance, which redistributes current after different regions switch. Our results highlight the potential of the emergent NDLR for characterizing superconductor–semiconductor hybrid systems and for nonlinear circuits. Further, this Josephson Hall bar geometry provides a platform for exploring the interplay between mesoscopic superconductivity and many-body ground states in graphene-based heterostructures.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Dynamic Chemical Changes of Ti3C2Tx MXenes in Halide Perovskite Precursor Environments
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-12 20:00 EDT
Kirill Sobolev, Nagaprasad Reddy Samala, Mariela J. Pavan, Sharon Hazan, Vladimir Ezersky, Shakked Schwartz, Omer Bartov, Adi Yakir, Michal Leskes, Tamar Goldzak Mizrachi, Yevgeny Rakita
The integration of two-dimensional Ti3C2Tx MXenes into Halide Perovskite (HaP) optoelectronics has shown immense potential for enhancing device performance, yet the fundamental chemical interactions within the precursor ink (a critical stage determining the final material state) remain largely unexplored. This study presents a comprehensive investigation into the chemical stability and surface evolution of Ti3C2Tx MXenes when exposed to the individual and combined components of a model methylammonium lead iodide (MAPbI3) solution. By combining detailed X-ray Photoelectron Spectroscopy (XPS) analysis with Density Functional Theory (DFT) calculations, we decouple the complex interactions between MXenes and the ink constituents. We demonstrate that elemental iodine (I2) and polyiodides (In-) act as aggressive oxidizers, triggering rapid degradation and dissolution of the MXene flakes. Conversely, lead iodide (PbI2) induces a slower oxidation process driven by the strong adsorption of Pb2+ ions onto oxygen terminated sites. In stark contrast, methylammonium iodide (MAI) exhibits a stabilizing effect: it adsorbs onto the MXene surface via hydrogen bonding, effectively passivating the flakes and retarding degradation. In addition, our results reveal that the sequence of precursor addition governs the MXene surface state, requiring extra caution, but also enabling further tunability. These findings provide a critical view on how MXene integration with materials, in general, and HaP in particular, should be perceived, providing a fundamental for their rational engineering.
Materials Science (cond-mat.mtrl-sci)
Realizing Two-Dimensional Altermagnets with 100% Spin Polarization along the [110] Direction in Ambidentate-Ligand Based Square Organometallic Lattices
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-12 20:00 EDT
Qing-Bo Liu, Xin-Yi Chen, Xiangyang Li, Xingxing Li, Jinlong Yang
Altermagnetism, as a novel magnetic paradigm, not only possesses a zero net magnetic moment, but also exhibits a substantial nonrelativistic spin-splitting effect. Currently, developing a simple and experimentally feasible method for designing altermagnets is eagerly pursued. Moreover, achieving 100% spin polarization along certain directions in valence or conduction bands for altermagnets remains challenging. To address these issues, based on a tight-binding model, we propose a viable chemical strategy for constructing organometallic altermagnets by using ambidentate ligands. Furthermore, in these organometallic altermagnets, direction-dependent 100% spin polarization along the [110] direction in band edges can be induced via the coexistence of altermagnetically spin-split dispersive and flat bands, where the flat band suppresses electron transport in one spin channel and the dispersive band enables conduction in the other spin channel. Then, via first-principles calculations, a screening of 90 two-dimensional ambidentate-ligand based square organometallic lattices leads to the identification of three altermagnetic materials, namely Fe(taz)2Cl2 (taz = 1,2,4- triazine), Co(app)2Cl2, and Fe(app)2Cl2 (app = 1,4-azaphosphinine), all of which possess 100% spin polarization along the [110] direction in valence bands, as well as notable piezomagnetic behavior. This study paves the way for achieving direction-dependent fully spin-polarization in altermagnetic materials.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Quadratic XY-anisotropy correction to the spontaneous staggered magnetization of the gapped XYZ spin-$1/2$ chain
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-12 20:00 EDT
The staggered order parameter of the gapped XYZ spin-$ 1/2$ chain follows from the eight-vertex solution, but in elliptic variables that fix the Hamiltonian couplings only implicitly. We derive a closed form for the coefficient governing the leading quadratic response of the spontaneous staggered magnetization to the XY anisotropy at fixed longitudinal anisotropy in the gapped antiferromagnetic regime. Starting from the Baxter–Kelland–Jimbo–Miwa–Nakayashiki polarization formula, we show that at fixed longitudinal anisotropy both the modular nome and the crossing-parameter variable of the formula move with the XY anisotropy, and that the motion of the crossing-parameter variable reverses the sign of the expansion at fixed elliptic variables. The coefficient is a rational term plus a Lambert series. It is strictly negative and bounded above by a rational function of the longitudinal anisotropy, to which it is asymptotic in the Ising limit. At the isotropic point it diverges as the inverse five-halves power of the distance to that point, and since the Lambert sum has an asymptotic expansion with exponentially small remainder, the subleading terms of the divergence also follow in closed form. When the XY anisotropy vanishes as the five-fourths power of the distance to the isotropic point, the ratio of the perturbed to the unperturbed order parameter tends to a Gaussian in the scaling variable, and the quadratic truncation is controlled when that variable is small. A fourth-order perturbative calculation in the spin chain, with no input from the eight-vertex solution, reproduces the leading strong-coupling behaviour, and infinite-DMRG calculations at four anisotropies in the gapped regime are consistent with the closed form.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech), Exactly Solvable and Integrable Systems (nlin.SI)
12 pages, 1 figure, 1 table
Drude, Where’s My Charge? End-to-End Learning of Polarizable Drude Force Fields for Polymer Electrolytes
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-12 20:00 EDT
Artur Lyssenko, KyuJung Jun, Rafael Gomez-Bombarelli
Molecular dynamics simulations of solid polymer electrolytes require force fields that are fast enough to converge ion transport over hundreds of nanoseconds, yet accurately describe the ion-polymer interactions that govern it. Fixed-charge force fields meet the first requirement but neglect electronic polarization, an effect often approximated by scaling ionic charges using empirically chosen factors. Here we present AutoDrude, a differentiable framework that parametrizes polarizable Drude force fields directly from DFT energies, forces, and dipoles, with no empirical tuning and at only 1.20 times the cost of a fixed-charge simulation. For PEO-LiTFSI, the dipole-constrained (hard-constraint) AutoDrude model reproduces the experimental ionic conductivity as accurately as the best charge-scaled model (17% versus 16% mean absolute percentage error). We compare the polarizable forcefield to fixed charge ones models by fitting a fixed charge model. Unlike the charge-scaled models tested here, however, AutoDrude also reproduces the dilute-limit cation transference number, its increase with salt concentration, and the absence of Li-TFSI contact ion pairs at low concentration. A penalty-based (soft-constraint) variant yields a closer fit to the DFT reference yet underestimates the conductivity by up to an order of magnitude, demonstrating that closer agreement with DFT training data alone does not guarantee accurate ion transport. These results indicate that although charge scaling can reproduce ionic conductivity the explicit inclusion of polarization is necessary to capture the concentration dependence of cation transport in PEO-LiTFSI.
Materials Science (cond-mat.mtrl-sci)
Ground-State Phase Diagram of the Effective Model with Antiferromagnetic Nearest-Neighbor and Ferromagnetic Next-Nearest-Neighbor Interactions in 1/1 Periodic Approximants to Icosahedral Quasicrystals
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-12 20:00 EDT
By performing complete enumeration of all configurations of magnetic moments, we have determined the ground-state phase diagram of the effective model with antiferromagnetic nearest-neighbor interactions $ J_1$ and ferromagnetic next-nearest-neighbor interactions $ J_2$ on the 1/1 periodic approximant to icosahedral quasicrystal. Depending on the ratio of $ J_2/J_1$ and the magnetic anisotropy arising from the crystalline electric field, various non-collinear ferrimagnetic orders and antiferromagnetic orders are shown to be stabilized, whose magnetic space groups are identified as $ R\bar{3}$ , $ C2’/m’$ , $ Pm’m’2$ and $ I_{\rm P}m’\bar{3}’$ . We have revealed the topological as well as magnetic property of each ground state with degeneracy, which is useful to understand experimental observations of magnetic structures and domains in the rare-earth-based 1/1 approximants.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
15 pages, 27 figures
J. Phys. Soc. Jpn. 95 (2026) 084705
Room-temperature ferroelectric p-wave magnet
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-12 20:00 EDT
Kaiwen Shen, Nicoly Hembeck, Warlley H. Campos, Jianting Dong, Bin Li, Yuhang Li, Gui Wang, Jan Priessnitz, Yifan Gao, Yingfen Wei, Hao Jiang, Xumeng Zhang, Ming Wang, Jia Zhang, Wu Shi, Qi Liu, Libor Šmejkal, Xianzhe Chen, Ming Liu
P -wave magnets exhibit odd-parity spin polarization in momentum space while retaining zero net magnetization, offering a promising route toward nonrelativistic spintronics. Previously reported p-wave magnets based on combined time-reversal and lattice-translation symmetry, Tt, have thus far exhibited ordering temperatures below the liquid-nitrogen range. Here, we demonstrate a distinct route to a pristine p-wave magnetism that does not require T t symmetry, and instead is based on incommensurate spin-spiral order. Specifically, the cycloidal magnetic structure of the multiferroic BiFeO3 (BFO) intrinsically realizes p-wave magnetism coexisting with ferroelectric polarization at room temperature. Combining symmetry analysis, density-functional-theory calculations, and circular photogalvanic-effect (CPGE) measurements, we find a large nonrelativistic spin splitting of approximately 100 meV associated with the cycloidal order. The resulting p-wave spin polarization gives rise to a characteristic CPGE response whose sign can be reversibly switched by electrically controlling the cycloid chirality. Our results establish ferroelectric BiFeO3 as a room-temperature platform for electrically switchable p-wave magnetism and provide a route toward voltage-controlled spintronic devices based on parity-breaking magnetic order.
Materials Science (cond-mat.mtrl-sci)
Symmetry-Enforced Topology and Van Hove Saddle Points in Hexagonal TiAs
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-12 20:00 EDT
Azizur Rahman, Shashi B Mishra, Sheraz Khan, Khushnood Shah, Xun Ma, Xiaoyang Lin, Tomasz Sobol, Lei Zhang, Weisheng Zhao, Min Zhang, Zahir Muhammad
We report the first successful growth of stoichiometric hexagonal TiAs single crystals (space group $ P6_3/mmc$ ) using chemical vapor transport and investigate their vibrational, electronic, topological, and magnetotransport properties. Polarized Raman spectroscopy identifies all four Raman-active phonon modes ($ A_{1g} + E_{1g} + 2E_{2g}$ ), consistent with the hexagonal crystal symmetry. First-principles calculations reveal nontrivial band topology characterized by a symmetry indicator $ \mathbb{Z}_4 = 2$ and a strong topological index $ \nu_0 = 1$ , together with symmetry-protected fourfold band degeneracies at the nonsymmorphic Brillouin-zone boundary. The Fermi surface exhibits an orbital-dependent crossover from quasi-two-dimensional cylindrical sheets to a corrugated three-dimensional structure along $ k_z$ . A Van Hove saddle point approximately 0.5 eV below the Fermi level along $ \Gamma\text{–}K$ is associated with a neck-disrupting Lifshitz transition and enhanced density of states. Magnetotransport measurements reveal a pronounced twofold angular magnetoresistance, consistent with anisotropic Fermi-surface geometry and open cyclotron orbits. Hall measurements indicate uncompensated, hole-dominated transport, accounting for the absence of extreme magnetoresistance and contributing to the field-orientation-dependent Hall response. These results establish hexagonal TiAs as a platform for exploring the interplay of nonsymmorphic band topology, Van Hove singularities, and anisotropic electronic transport in transition-metal monopnictides.
Materials Science (cond-mat.mtrl-sci)
10 pages, 6 figures
Vacuum-field-mediated Landau-level reconstruction in a cavity-coupled two-dimensional electron gas
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-12 20:00 EDT
We study a two-dimensional electron gas in the integer quantum Hall regime coupled to a single spatially modulated cavity mode in the static off-resonant limit. Retaining both paramagnetic and diamagnetic contributions on equal footing, we derive a gauge complete single-particle Hamiltonian in which virtual photon exchange generates a periodic kinetic renormalization and a diamagnetic scalar potential. Both terms transfer momentum by $ 2k_0$ and displace guiding centers by $ \Delta X=2k_0\ell_B^2$ , forming a finite-$ k_0$ momentum ladder. Diagonalizing the strip Hamiltonian, we find that the ladder reconstructs the Landau-level band structure and redistributes, rather than multiplies, the associated chiral edge states. Occupied-subspace Chern numbers remain $ C_\nu=\nu$ for $ \nu=1,2,3$ throughout $ 0\le\lambda_{\mathrm{cav}}\le 0.5$ , while the bulk gaps decrease without closing. Strip Kubo responses show cavity-induced displacements of the Hall-step energies; at finite width the plateau heights are noninteger and approach the integers as $ L_x$ increases. The ladder is spectrally resolved at $ k_0\ell_B=0.5$ and collapses at $ k_0\ell_B=0.1$ . These results isolate a spatially local, finite-$ k_0$ momentum ladder as a clean-system mechanism by which a structured vacuum field reconstructs quantum Hall spectra and strip transport without changing the integer topology, complementary to cavity-mediated all-to-all hopping.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
9 pages, 8 figures
High-Throughput Discovery of Chiral Carbon-Boron Semimetals with Weyl Topology and Phonon-Mediated Superconductivity
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-12 20:00 EDT
Lizhou Yang, Wenneng Zhao, Ye Yang, Weiwei Chen, YongKeat Chan, Chen-Hao Lv, Qing-Bo Liu, Yujia Xiang, Xinming Qin, Zedong Li. Weiyi Wang, Jinlong Yang, Wei Hu
Chiral crystals provide a natural platform for unconventional topological fermions, while light-element carbon–boron frameworks are promising for phonon-mediated superconductivity owing to strong covalent bonding and high phonon frequencies. Here, we combine Wyckoff-position-based structure generation with high-throughput first-principles calculations to search for C–B crystals in selected hexagonal chiral space groups. Starting from 972 generated $ \mathrm{C}_m\mathrm{B}_n$ structures ($ m,n=1\text{–}4$ ), successive filters based on energetic stability, dynamical stability, electronic metallicity, topological band features, and thermal stability identify six stable candidates: $ (\mathrm{C}_3\mathrm{B}_2)_8$ , $ (\mathrm{C}\mathrm{B}_2)_3$ , $ (\mathrm{C}\mathrm{B}_4)_6$ , $ (\mathrm{C}_3\mathrm{B}_2)_6$ , $ (\mathrm{C}_2\mathrm{B}_3)_6$ , and $ (\mathrm{C}\mathrm{B}_2)_6$ . These materials host diverse topological semimetal states near the Fermi level, including charge-one, charge-two, and charge-three Weyl points, nodal rings, and nodal-surface states. Notably, $ (\mathrm{C}_3\mathrm{B}_2)_8$ exhibits screw-symmetry-protected charge-three Weyl points and strong electron–phonon coupling, yielding a McMillan transition temperature of $ 31.1,\mathrm{K}$ for the Coulomb pseudopotential parameter $ \mu^\ast = 0.10$ . In addition, $ (\mathrm{C}\mathrm{B}_2)_3$ hosts multiple charge-one Weyl points and pronounced anisotropic multiband superconductivity revealed by fully anisotropic Eliashberg calculations. These results extend the materials scope of topological semimetals with phonon-mediated superconductivity to chemically designed chiral light-element structures.
Materials Science (cond-mat.mtrl-sci)
23 pages, 4 figures,
Ionic liquid/PDMS coated nanostructured ZnO surfaces for superior antibacterial activity
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-12 20:00 EDT
Anushika Rohilla, Ajit Seth, Mayank Bharadwaj, Rumal Singh, Sajal K Ghosh
The development of nanostructured antibacterial surfaces has gained significant attention due to the urgent need to combat bacterial colonization and biofouling across food, healthcare, and marine sectors. Among functional metal oxides, zinc oxide (ZnO) nanostructures are particularly promising owing to their rich morphology, favourable physicochemical attributes, and intrinsic bactericidal properties. Here, we utilize a green, eco-friendly Hot Water Treatment (HWT) method to fabricate dense ZnO nanorod arrays on zinc substrates. To overcome the practical limitations and challenges of conventional antibacterial coatings, such as poor operational stability, cytotoxicity, and the risk of antimicrobial resistance, we developed a durable hybrid coating composed of an imidazolium-based ionic liquid stabilized with polydimethylsiloxane. The resulting hybrid-coated nanostructured surfaces exhibit superior antibacterial efficacy against Escherichia coli through a combination of topography-induced mechanical strain and membrane disruption.
Soft Condensed Matter (cond-mat.soft)
19 pages, 8 figures
Real-Time Relaxation Dynamics of Dark Excitons in Mirror-Symmetric Monolayers
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-12 20:00 EDT
Rishabh Saraswat, Mantasha Ansari, Rekha Verma, Sitangshu Bhattacharya
Symmetry governs which exciton-phonon (\textit{exc-ph}) scattering channels \textit{can} exist, but not which a relaxing exciton actually uses. Combining group theory with \textit{ab initio} many-body perturbation theory, we derive the mirror parity $ \sigma_h$ , of finite-momentum excitons in planar $ D_{3h}$ monolayers, and form exact \textit{exc-ph} selection rules that hold across the whole Brillouin zone. The parity of the lowest exciton band changes across a closed contour. The even phonons connect states of the same parity, while odd phonons connect states of opposite parity. We use these rules to compute exciton linewidths and we solve the real-time Boltzmann transport equation for monolayer GaN as the test case and benchmark it against monolayer \textit{h}BN.
Strongly Correlated Electrons (cond-mat.str-el)
Odd-Parity Crystalline Electric Field and Multipoles in Icosahedral Quasicrystal and Approximant: Magnetic Toroidal and Electric Dipoles in Ce-Based Systems
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-12 20:00 EDT
Shinji Watanabe, Syunta Furuya, Mitsuaki Kawamura
Quasicrystals (QCs) lack periodic arrangement of atoms but possess unique structural order distinct from periodic crystals and random systems. The electronic property is far from complete understanding. Here we have formulated not only even-parity but also odd-parity crystalline electric field (CEF) in the Ce-based icosahedral QC and approximant crystal (AC) on the basis of the point charge model. Under the odd-parity CEF due to local-inversion symmetry breaking at the Ce site, the hybrid wavefunction of 4f and 5d states at Ce is shown to give rise to the odd-parity multipoles such as electric dipole and magnetic toroidal (MT) dipole. We have found that the vortex order in the 1/1 AC where the magnetic moments on each icosahedron swirl is characterized by the cluster-type MT moment. The ferroic alignment of the cluster MT moments in the vortex order gives rise to the electro-magnetic effect. The cluster-MT moment is shown to be resonated with the MT dipole moments in each icosahedron by tuning the 4f energy level and 5d energy level so as to approach. We have revealed a noncollinear magnetic structure is stabilized in the ground state of the icosahedral QC cluster, behind which there exists underlying mechanism to prefer the ferroic interaction for the net MT dipole moments between the icosahedrons. We point out that the 4f and 5d energy levels can be made approach at the valence transition or the valence crossover, which is ubiquitous in the rare-earth based ACs and QCs.
Strongly Correlated Electrons (cond-mat.str-el)
52 pages, 12 figures
J. Phys. Soc. Jpn. 95 (2026) 104708
Parity-Anomalous Hall Response of Chiral Lifshitz Fermions
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-12 20:00 EDT
Yanmiao Han, Rundong Zhao, Yu-Hao Wan
The parity anomaly of a single massless Dirac fermion is manifested as a half-quantized Hall response once the required parity-breaking regularization is supplied. We study the corresponding response for two-dimensional chiral Lifshitz fermions. For a node with low-energy coupling (qx +iqy)^N, the Fermi-loop winding number W = N gives an anomalous Hall response {\sigma}xy^anom = (W/2)e^2/h. We examine this mechanism in chiral multilayer Haldane models tuned to a valley-selective critical line, where a single gapless chiral Lifshitz fermion remains at the K valley. For the AB, ABC, and ABCA stacks, the projected pseudospin textures give W = 2, 3, 4, while Kubo calculations yield {\sigma}xy = (1, 3/2, 2)e^2/h; integrated equilibrium boundary currents reproduce the same W/2 sequence. Six-terminal simulations with dephasing further show that the Hall conductivity is quantized at W/2 while the longitudinal conductivity remains finite. These results identify gapless chiral Lifshitz fermions as a higher-order, winding-controlled generalization of the parity-anomalous Hall response, distinct from a quantum anomalous Hall insulating state even when W/2 is an integer.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Evolution and breakdown of chiral anomaly in Weyl semiconductor tellurium
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-12 20:00 EDT
Zhifeng Xue, Jiaji Zhao, Yi Ji, Fuyang Chen, Nannan Tang, Gangjian Jin, Bing Shen, Bin Wang, Yang Wang, Mingxi Chi, Jin-Zhu Zhao, Ruiqiang Wang, Qizhong Zhu, He Wang, Huakun Zuo, Donghui Guo, Dingyong Zhong, Mingxun Deng, Huichao Wang
Chiral anomaly in topological materials manifests as negative longitudinal magnetoresistance, yet the tunability and evolution of this effect remain elusive. Here we show that doped tellurium serves as a versatile platform to realize a giant negative longitudinal magnetoresistance that is highly tunable via the Fermi level and magnetic field. By moving the Fermi level towards the Weyl point, we observe a pronounced enhancement of negative magnetoresistance, which arises from chiral anomaly and robustly persists up to ambient temperature. Beyond the quantum limit, the system exhibits positive linear magnetoconductance, serving as a compelling transport signature of the chiral anomaly in the lowest Landau level. Notably, in the extreme quantum limit at cryogenic temperatures, the magnetoresistance undergoes a dramatic reversal from negative to positive. This reversal points to a potential field-induced phase transition into a collective electronic state driven by enhanced electron-electron interactions. Our findings provide valuable insights into the unconventional chiral transport and emergent correlated quantum states under extreme magnetic fields.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph), Quantum Physics (quant-ph)
Commun. Phys.(2026)
Role of composition-tuned disorder on magnetic exchange interactions in NiRuMnGa
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-12 20:00 EDT
Manikantha Panda, Prabuddha Kant Mishra, Vinod Kumar, Wilfrid Prellier, Rahul Sharma, Tapas Paramanik
We report the experimental investigation of the quaternary Heusler alloy NiRuMnGa, complemented by first-principles calculations. The energetically favorable crystal structure was identified from first-principles calculations and subsequently used as the structural model for refinement of the powder X-ray diffraction data. The refinement shows good agreement with the experimental pattern and reveals substantial B2-type disorder involving Ni/Ru and Mn/Ga site intermixing. The dc magnetic response exhibits pronounced ZFC–FC irreversibility near $ \sim 48$ K, with the irreversibility temperature shifting toward lower temperatures under increasing magnetic field, indicating a field-sensitive glassy state. The isothermal magnetization remains unsaturated up to 7 T, reaching only $ \sim 0.4,\mu_{\mathrm{B}}$ /f.u., accompanied by pronounced hysteresis, suggesting competing exchange interactions and frustrated magnetic moments. AC susceptibility, together with magnetic relaxation and memory measurements, confirms slow spin dynamics characteristic of a cluster glass state. The lack of a discernible heat-capacity anomaly near the irreversibility temperature further supports the absence of conventional long-range magnetic order. Collectively, these results demonstrate that competition between ferromagnetic and antiferromagnetic interactions in NiRuMnGa leads to magnetic frustration and stabilizes a cluster glass state.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
13 pages, 10 figures, regular article
Assessing quantitative phase reliability in electron ptychography using a twisted trilayer WS2 thickness staircase
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-12 20:00 EDT
Hu Bao, Qilong Feng, Kun Ye, Tianyu Xue, Stephen J. Pennycook, Yihan Zhu, Anmin Nie, Shoucong Ning, Jing Tao
The phase of an electron wave is sensitive to the local electrostatic environment and can therefore provide information about atomic-scale structural variations. In electron ptychography, however, specimen thickness, multiple scattering and projected atomic overlap can complicate the quantitative interpretation of the reconstructed phase. Here, we use a twisted trilayer WS2 thickness staircase containing monolayer, bilayer and trilayer regions as an internal reference, with all regions measured under identical experimental conditions. The mean W-column phase increases by approximately 13.2% from the monolayer to the bilayer region, compared with only 4.7% from the bilayer to the trilayer region, revealing a nonlinear thickness dependence. W-S overlap has little effect on the W-column phase, whereas short-range projected W-W overlap increases it by approximately 8-9%. These results provide a benchmark for evaluating quantitative phase measurement in multilayer WS2 and for assessing phase-based mapping of local electrostatic potential, charge-density and three-dimensional atomic-scale polarization.
Materials Science (cond-mat.mtrl-sci)
15 pages, 4 figures
Electron- and hole-doped superconductivity in two-dimensional electride ZrX$_2$ (X = Cl, Br, I)
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-12 20:00 EDT
Tian-Xin Liu, Xin-Yang Li, Zuo-Wei Yin, Jing Jiang, Ben-Chao Gong, Wei Fan, Xiao-Le Qiu, Kai Liu
Two-dimensional (2D) superconducting systems have recently emerged as a frontier in condensed matter physics, driven by their unique physical properties and potential applications. Using first-principles calculations, we show that monolayer ZrX$ _2$ (X = Cl, Br, I), which is a family of 2D semiconducting electrides, hosts phonon-mediated superconductivity under both electron and hole dopings. Electron doping in ZrX$ _{2}$ can achieve high superconducting transition temperatures at very low concentrations, with ZrBr$ _2$ reaching $ T_c = 30.0$ K at 0.01 \textit{e}/f.u., followed by ZrCl$ _2$ (22.5 K at 0.05 \textit{e}/f.u.) and ZrI$ _2$ (18.1 K at 0.01 \textit{e}/f.u.), for which the high $ T_c$ originates from the flat conduction band minimum, with Van Hove singularities nearby enhancing the density of states. In contrast, hole doping requires higher concentrations (0.2–0.25 \textit{h}/f.u.) to activate superconductivity, yielding $ T_c \sim 2$ K, and approaches a magnetic instability at elevated doping levels. By comparing with InSe and LaBr$ _2$ , we identify the spatial location and orbital character of excess electrons as key factors determining the strength of hole-doped superconductivity and the nature of competing orders. These findings establish monolayer ZrX$ _2$ as a platform for bipolar superconductivity in a 2D electride and provide insights into flat-band engineering for high-$ T_c$ superconductors.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci)
Orbital transfer reveals material-selective structure in Rydberg excitons
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-12 20:00 EDT
Mengli Wang, Peng Chen, Wenqi Xue, Haonan Xia, Hong Zhang, Benniu Zhang
Rydberg excitons in atomically thin semiconductors offer a sensitive view of dielectric screening and electronic structure. As their spectra become increasingly well resolved, a central question is how much material information an effective Hamiltonian can predict beyond the states used to determine it. Using the 1s, 2p and 2s levels to determine a scalar Rytova-Keldysh Hamiltonian, we test its transfer to the excluded 3p state. The transfer deviations have opposite signs: the observed 3p lies 7.38 meV below the prediction in MoSe2 and 5.58 meV above it in WS2; the opposite signs persist across the complete reported +/-2-sigma peak-error boxes. In a separate high-field-calibrated benchmark, RK removes 66.8% of the orbital error of a pure two-dimensional Coulomb reference, making the remaining state-selective deviations particularly informative. After separating gap and common-scale contributions, the residuals reveal distinct material-dependent orbital patterns and constrain simple multichannel descriptions. For WS2, the measured 2p/3p curvatures yield a parameter-fixed prediction, Q4p=+4.08 meV, for a future same-platform measurement. Together these results show how a well-performing spectral model can be tested for transferable physical information, with the next unmeasured state providing an independent experimental check.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
24 pages, 9 figures
X-ray absorption spectroscopic studies of oxygen-deficient double perovskite oxide NdBaCo$2$O${5+δ}$ ($δ\sim 0.65$)
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-12 20:00 EDT
Himanshu Pant, S. Khalid, R. Bindu
The degree of oxygen vacancy in A-site-doped layered double perovskite oxides can lead to anion vacancy ordering, which subsequently results in distinct superstructures. We have studied oxygen deficient double perovskite oxide, NdBaCo$ 2$ O$ {5+\delta}$ ($ \delta \sim$ 0.65), utilising X-ray absorption near edge structure (XANES) spectroscopy complemented by multiple scattering and first-principles calculations based on density functional theory (DFT+U). The present results establish a direct correlation between oxygen-vacancy distribution, magnetic inhomogeneity, and charge transport in layered cobaltates. Our investigations on the Co K, Ba, and Nd $ L{\mathrm{III}}$ edges suggest that the near-edge spectra, based on the number and shape of the spectral features, indicate the value of $ \delta$ for the compound under study lies closer to 0.75. The analysis of the Ba $ L_{\mathrm{III}}$ edge spectrum confirms the +2 oxidation state for Ba ions. The Co K-edge near-edge spectra suggest the possibility of oxygen vacancies arising at the basal sites in addition to the apical sites. This is counterintuitive to the common understanding that oxygen vacancies usually occur at the apical sites, i.e., in the lanthanide (Nd) layer in these compounds. Such a distribution of oxygen vacancies naturally explains the Griffith phase and the conduction mechanism of variable range hopping observed in the compound. The vacancy distribution, when at the optimum level, can also bring about easier oxygen ion mobility and a more sensitive and faster oxygen sensor. We believe that our results will help in tailoring oxygen-ion mobility and enhancing oxygen-sensing performance.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
13 pages, 10 figures
Imbibition dynamics under dissolution-driven fluid thickening
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-12 20:00 EDT
H. W. Almeida, A. F. V. Matias, R. C. V. Coelho, N. A. M. Araujo
The imbibition of milk into a biscuit provides an example of a broader class of processes in which a liquid invades a porous material, dissolving components of the solid and thereby modifying its own rheology. This coupling between imbibition, dissolution, and evolving fluid rheology also occurs in food processing, filtration, and reactive porous media. While the resulting changes in fluid viscosity are known to affect imbibition, a quantitative description of how this evolving rheology determines the imbibition dynamics is still lacking. Here, we establish such a description for dissolution-driven fluid thickening. For a capillary tube in the well-mixed limit, we derive a generalized Washburn law showing that the evolving viscosity can be incorporated through a rescaled time given by the accumulated inverse viscosity. This predicts a collapse of the imbibition dynamics for different dissolution rates, which we confirm numerically using coupled free-surface and solute-transport simulations. When diffusion is slower, concentration and viscosity become spatially heterogeneous, resulting in a weaker retardation of the advancing liquid than predicted by the well-mixed theory. We then consider disordered porous media and quantify how dissolution-driven thickening and variations in pore geometry affect the dynamics. Our results extend the classical Washburn description to imbibition with evolving fluid properties and provide a quantitative basis for understanding fluid uptake when interactions with the solid progressively modify the rheology of the invading liquid.
Soft Condensed Matter (cond-mat.soft)
Insights on the volume variation of LiCoxMn2-xO4 electrode upon cycling: a correlative operando XRD and XAS study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-12 20:00 EDT
Eunike Mahayoni, Louiza Larbi, Romain Batiot, Anatole Weill, Damien Brégiroux, Antonella Iadecola, Arnaud Perez
Understanding volume changes in high-voltage spinel cathodes is essential for mitigating mechanical degradation and improving cycling stability. However, linking these changes to cation-specific redox processes remains challenging. Here, we combine operando X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) to investigate the LiCoxMn2-xO4 spinel system, which exhibits a cubic structure and isotropic lattice response, in order to correlate the evolution of the local and long-range structure. Five compositions (x = 0, 0.25, 0.5, 0.75, and 1.0) were synthesized and electrochemically characterized, with x = 0, 0.5, and 1.0 examined in detail under identical cycling conditions. XAS at the Mn and Co K-edges reveals distinct Mn4+/Mn3+ and Co4+/Co3+ redox processes, with Mn redox activity dominating below 4.7 V and Co redox triggered at higher potentials. Chemometric tools for XAS data analysis further resolve the evolution of local structure during cycling. Both XRD and XAS capture consistent trends in volume evolution, despite probing different structural length scales. Increasing Co content progressively decreases the overall volume change, from 5.0 % to 1.6 % by XAS and from 5.8 % to 2.1 % by XRD. These results demonstrate that Co substitution suppresses electrochemically induced structural strain and establish a direct link between cation-specific redox activity and volumetric evolution. The correlative operando XRD/XAS approach provides a framework to investigate newly designed low-strain, high-energy cathodes with improved cycling stability.
Materials Science (cond-mat.mtrl-sci)
Equal-Spin local and nonlocal Andreev reflection in altermagnet/superconductor/altermagnet junction
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-12 20:00 EDT
Kai-Yi Lyu, Xing Wang, Yu-Xian Li
We investigated the equal-spin Andreev reflection phenomenon in an altermagnet/super-conductor/altermagnet (AM/SC/AM) junction, focusing on the roles of the crystal orientation angle and the Néel vector. The crystal orientation angle in the AM effectively determines the spin-dependent transport channels for both electrons and holes, leading to orientation-dependent local and crossed Andreev reflection in the AM/SC/AM junction. We studied how and under what conditions this equal-spin Andreev reflection occurs. Rotating the Néel vector in the AM substantially increases spin-flip channels for both electrons and holes, giving rise to equal-spin Andreev reflection. When the Néel vector $ \theta=\pi/2$ , the spin-dependent transmission channels for crystal orientations $ \alpha=0$ and $ \alpha=\pi/2$ are completely the same, the Andreev reflection coefficients remain different, reflecting the distinct roles of the Néel vector in spin space and the crystal orientation in real space. By tuning the crystal orientation angle and the Néel vector, orientation-dependent conventional and equal-spin Andreev reflection can be realized. This study reveals that Néel vector rotation is the direct cause of equal-spin Andreev reflection in AM/SC/AM junctions and provides a viable pathway for realizing spin-dependent superconducting transport phenomena in AM heterojunctions.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Graphene double quantum dot as a solid-state two-level system in the THz range
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-12 20:00 EDT
Alexis Wietzke, Solen Coeymans, Benjamin Hue, Simon Messelot, Aurelien Schmitt, Michael Rosticher, Kenji Watanabe, Takashi Taniguchi, Jerome Tignon, Sukhdeep Dhillon, Rebeca Ribeiro, Audrey Cottet, Matthieu Delbecq, Takis Kontos, Juliette Mangeney
Matter-based two-level quantum systems are fundamental building blocks of quantum technologies, underpinning applications in quantum computing, simulation, communication, and sensing. Today, most of these two-level quantum systems, including Rydberg atoms, trapped ions, superconducting circuits, molecules, and quantum dots, involve transition frequencies in microwave or optical domains. However, extending their transition frequency to the THz spectral range could provide numerous benefits, leveraging the unique properties of THz radiation. Here, we show that an hBN-encapsulated graphene double quantum dot realizes a two-level system with a transition frequency in the THz spectral range. Using low-temperature transport spectroscopy in the dark combined with modeling based on nonequilibrium Green’s function formalism, we demonstrate the formation of an artificial molecule, featuring bonding and antibonding states separated by an energy of up to 0.6 meV, corresponding to a resonance frequency of 0.145 THz. This approach provides direct access to important parameters of open double quantum dot systems, including tunneling rates, offering a practical alternative to conventional techniques such as photon-assisted tunneling, which are challenging to implement at THz frequencies. The realized 2D-material-based THz two-level system, compatible with direct on-chip integration, could serve as a key building block for future THz quantum technologies. Furthermore, by involving a single-electron transition, coupling these devices to a THz resonator could enable the exploration of ultra-strong light-matter interactions at the fundamental limit of a single transition coupled to a single cavity, beyond the reach of existing THz quantum systems based on collective transitions.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
Theory of exciton-exciton interactions in crystalline systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-12 20:00 EDT
L. Maisel Licerán, H.T.C. Stoof
Excitons are bound electron-hole pairs in semiconductors whose interactions influence optical properties and determine their collective behavior and emergent correlated phases. Despite the theoretical and experimental significance of these phenomena, a microscopic theory of exciton-exciton interactions that takes into account the full composite nature of these quasiparticles is lacking. Here, we present a general theory of exciton-exciton interactions that builds upon our previous publication [Physical Review B 113, 155440 (2026)], which applied only to conventional semiconductors with weak band hybridization. By contrast, the theory presented here is valid in virtually any crystalline semiconducting system and can be applied to the study of biexciton formation and correlated excitonic phases in systems where band topology, quantum geometry, and moiré effects play a significant role. In addition to the analytical theory, we also present results in simple systems with flat bands with a nontrivial quantum metric and show that the biexcitonic spectrum differs strongly from that in the case without quantum geometry. Our theory paves the way for accurate quantitative calculations of biexciton spectra and excitonic many-body phases in modern condensed-matter systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Quantum Gases (cond-mat.quant-gas), Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
18 pages, 8 figures
Ultrafast laser-stimulated field emission from a metal: a non-equilibrium Green’s functions approach
New Submission | Other Condensed Matter (cond-mat.other) | 2026-10-12 20:00 EDT
Luciano Jacopo D’Onofrio, Adolfo Avella, Martin Eckstein
Ultrafast laser-assisted field emission from metallic nanotips is a promising route for generating coherent electron pulses. However, existing theoretical models often neglect many-body strong correlation effects in the emitter’s electronic structure and its response to the optical field. In this work, we propose a theoretical framework based on the non-equilibrium Green’s function formalism to simulate the out-of-equilibrium electron dynamics across a strongly driven matter-vacuum interface, in a one-dimensional model. Treating the tip-vacuum coupling perturbatively, we find that the interplay between strong-field emission and multi-photon emission regimes can be described in terms of a filtering of the emitter’s local density of occupied states through field-dressed vacuum propagators. By including electron-electron interactions via the second-Born approximation, we show that correlation-induced modifications in the electronic structure are directly transferred to the far-field spectrum. Finally, by self-consistently solving the Dyson equation at the interface, we uncover a dynamic back-action regime driven by the optical field, characterized by a periodic polarization of the emitter, which reshapes the far-field spectrum. This shows that the non-equilibrium Green’s functions approach provides a versatile framework for exploring and analyzing field emission of correlated electrons.
Other Condensed Matter (cond-mat.other), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el), Computational Physics (physics.comp-ph)
16 pages, 11 figures
Atomic Edge Resonators Flatten Phonon Bands in Biphenylene Nanoribbons
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-12 20:00 EDT
V. L. Katkov, N. M. Chtchelkatchev, V. A. Osipov
We show that H–F edge complexes in biphenylene nanoribbons act as intrinsic atomic resonators, flattening low-frequency phonon branches. With increasing wave vector, flexural and twisting vibrations concentrate at the edges while motion of the carbon backbone is suppressed. Displacement profiles and edge-mass tuning identify a local-resonance mechanism, an atomic counterpart of a tuned mass damper. Combining machine-learned interatomic potentials, frozen-phonon calculations, and density-functional tight binding, we find that weakly dispersive modes contribute substantially to thermal band-gap narrowing. Zero-point motion shifts the calculated gap closure toward the experimentally observed ribbon widths. A hexagonal boron nitride substrate preserves the principal spectral features while reducing thermal renormalization. These results establish edge chemistry as a route to nearly flat phonon bands and connect a local atomic resonance to the electronic response of an entire nanoribbon.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Interplay of disorder and spin liquid physics in the triangular-lattice antiferromagnet YbZn2GaO5
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-12 20:00 EDT
Hafsa Zeroual, Shams Sohel Islam, Toni Shiroka, Thomas James Hicken, Rabindranath Bag, Sara Haravifard, Hubertus Luetkens, Philippe Mendels, Edwin Kermarrec, Fabrice Bert
YbZn2GaO5 has recently emerged as a structurally ideal triangular-lattice antiferromagnet and a promising candidate for hosting a U(1) Dirac quantum spin-liquid (QSL) ground state. However, signatures of broadened crystal electric field (CEF) excitations have raised questions about potential site disorder and its impact on the intrinsic spin dynamics. In this study, we employ 71Ga nuclear magnetic resonance (NMR) and muon spin relaxation (muSR) to microscopically probe both the structural and magnetic properties of YbZn2GaO5. NMR spectra reveal two inequivalent 71Ga sites and a broad distribution of quadrupolar frequencies, providing clear evidence of Ga$ ^{3+}$ /Zn$ ^{2+}$ site mixing and local CEF randomness. The NMR spin-lattice relaxation rate exhibits, down to 1.3~K, a power-law temperature dependence, consistent with persisting spin dynamics below the exchange energy scale in a frustrated magnet. Complementary muSR measurements further show that the spin dynamics persist down to 30mK, with no signs of spin freezing. Together, these results establish that YbZn2GaO5 presents substantial structural disorder, while the persistence of dynamic spin fluctuations down to the lowest temperatures may indicate the survival of QSL-like excitations despite such disorder.
Strongly Correlated Electrons (cond-mat.str-el)
Pulse-by-pulse imaging of reversible, collective reshaping in laser-excited gold nanorods
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-12 20:00 EDT
Mees Dieperink, Loriane Monin, Ichiro Ohnishi, Takeo Sasaki, Yu Jimbo, Erik Garnett, Wiebke Albrecht
Nanomaterial properties are governed by atomic structure, and driving structural changes on demand could enable materials with programmable properties. Pulsed light is the most controllable route: wavelength, fluence, polarization and pulse timing can each be tuned to inject energy with nanometre and picosecond precision and mould atomic positions. Yet the spatiotemporal dynamics of these transformations have remained hidden, inferred only from before-and-after snapshots. Here we track gold nanorods in a transmission electron microscope under pulsed optical excitation, quantifying the structural transition frame by frame. The rods enter an unexpectedly dynamic regime: material redistributes within and between particles, twin boundaries nucleate and propagate, rods hundreds of nanometres apart reshape in concert, and individual rods almost vanish before recovering their original shape, indicating a structural memory. Driving and following these transformations with pulse-synchronized in situ electron microscopy could turn light-induced reshaping into a tool for setting structure, and consequently properties, on demand.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Quantitative Eshelby stability: local and finite-shape theory through AI-assisted mechanics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-12 20:00 EDT
How can human researchers use artificial intelligence (AI) to make progress on difficult mechanics problems while retaining control of physical significance, mathematical rigor, and validation? We explore this opportunity through a quantitative stability problem rooted in the Eshelby conjecture. For a uniform dilatational eigenstrain in a homogeneous isotropic solid, we establish a nonlinear two-sided relation between whole-interior strain heterogeneity and a geometry-only distance from the ellipsoid family, with half-order Sobolev scaling that captures morphological length scale. We then develop a complementary finite-shape theory: ellipsoidal subtraction yields an exact residual-field budget from which systematically convergent upper and lower bounds are obtained for a prescribed geometry. Applied to protruded, indented, and necked inclusions, the bounds agree with independent displacement-based finite-element calculations. The study also documents a human-led, AI-assisted research process in which researchers select consequential problems, shape targets, audit arguments, require independent checks, and interpret mechanics, while AI broadens analytical exploration and supports computation. This experience also led us to develop Open Problems in Mechanics, a versioned community-facing map that makes selected mechanics questions, their known/open boundaries, and criteria for progress explicit.
Materials Science (cond-mat.mtrl-sci), Classical Physics (physics.class-ph)
33 pages, including 16 pages of Supplementary Information; 4 figures
Temperature evolution of spin dynamics in extended Kitaev models within an Abrikosov fermion theory beyond mean field
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-12 20:00 EDT
The $ S=1/2$ Kitaev model provides an exactly solvable setting in which spin fractionalization produces itinerant Majorana fermions coupled to an emergent $ \mathbb{Z}_2$ gauge field. In realistic Kitaev magnets, however, non-Kitaev interactions break integrability and make their finite-temperature dynamics difficult to calculate. We develop a finite-temperature parton mean-field theory based on the Abrikosov-fermion representation and incorporate the effects of exchange interactions through the random phase approximation to calculate the dynamical spin structure factor. For the pure Kitaev model, the method reproduces a strong, nearly dispersionless peak at a finite low energy together with a broad continuum at higher energies. It also reproduces the momentum dependence of the dynamical spin structure factor and its temperature evolution, including the downward shift of the low-energy spectral weight, in qualitative agreement with continuous-time quantum Monte Carlo calculations. Within the present theory, the contraction of the continuum is traced to the temperature-induced reduction of the bond amplitudes, which narrows the parton bands and compresses the two-parton phase space. For ferromagnetic Kitaev coupling, the energy of the low-energy peak is minimized at the $ \Gamma$ point for a ferromagnetic Heisenberg interaction and maximized there for an antiferromagnetic interaction. In the ferromagnetic Kitaev-$ \Gamma$ model, the static response develops a finite-momentum softening, indicating an instability toward the period-three magnetic order reported in numerical studies. For uniform-ferromagnetic states selected by a $ [111]$ magnetic field, we find that a broad parton continuum coexists with magnonlike dispersive structures, producing spectral features consistent with a spinon-to-magnon crossover.
Strongly Correlated Electrons (cond-mat.str-el)
29 pages, 13 figures
The Stone-Wales trefoil: a new topological defect in graphene
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-10-12 20:00 EDT
M.V. Kondrin, Y.B. Lebed, V.V. Brazhkin
Specific heat of graphite at high temperatures demonstrates significant deviation from the ``3R’’ Dulong-Petite law. It can be explained by accumulation of defects with formation energy as low as 1.45 eV. Based on the density functional theory calculations, we propose a possible candidate of topological defects, whose energy is comparable to the growth activation energy.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
VN-GraphGG: von Neumann–Mullins–based graph grain growth simulation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-12 20:00 EDT
Yuntong Huang, Zhihao Li, Shuyang Dai, Chang Ma, Yang Xiang
Efficient simulations of grain growth are essential for investigating the process-structure-property relationships in polycrystalline materials. We introduce a two-dimensional von Neumann-Mullins-based graph grain growth simulation (VN-GraphGG), which couples the grain-scale kinetics with microstructure reconstruction. The polycrystalline microstructure is represented as a graph with grain and junction nodes. The grain-area evolution on the grain graph is governed by the von Neumann–Mullins (VN) law, while a graph neural network is trained to reconstruct the microstructure from the graph. This separation allows kinetic coefficients to be varied without retraining the neural reconstruction model. Topological changes during grain growth such as disappearance of grains and changes in neighbor relations are handled straightforwardly through reconstruction and postprocessing. Simulations demonstrate accurate predictions of VN kinetics and coarsening statistics, and significant speedup over the phase-field simulations. The proposed method provides a foundation for efficient grain growth simulation based on grain-scale kinetics, opening the way to incorporate a broader range of physical mechanisms. An application example is presented for abnormal grain growth, in which kinetic heterogeneity significantly influences the grain microstructure evolution.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
37 pages, 5 figures, 1 table
Predicting Nanofabrication Variance: A Conditional Diffusion Model
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-12 20:00 EDT
Wenhan Zhang, Ben Mills, Oleksandr Buchnev, Kevin F. MacDonald
Micro- and nanostructures fabricated by focused ion beam (FIB) milling invariably deviate from input designs due to systematic and stochastic effects such as ablation-rate fluctuations, and redeposition. As such, nominally identical iterations of a given process yield a distribution of non-identical fabrication outcomes, leading to variations in the physical (optical, mechanical) properties of fabricated structures. Existing models of the milling process typically predict a single deterministic fabrication result, neglecting this variability. Here we present a conditional diffusion model that learns the statistical distribution of process outcomes conditioned on input design, enabling it to predict a realistic distribution of possible output sample structures. These predictions accurately reproduce edge morphology, linewidth variations, and defect probabilities observed in fabricated samples, enabling statistical analysis of milling performance and the identification of dominant structural and process parameter-dependent deformation modes. The work establishes a probabilistic modelling framework for fabrication variability analysis and fabrication-aware design optimization.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Computational Physics (physics.comp-ph)
8 pages, 3 figures
Magnetic-field-induced detwinning of orientational domains in altermagnet $α$-MnTe: A single-crystal neutron diffraction study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-12 20:00 EDT
Feihao Pan, Yishui Zhou, Sabreen Hammouda, Yinghao Zhu, Soohyeon Shin, Karin Schmalzl, Wolfgang Schmidt, Eric Ressouche, Oscar Fabelo, Yixi Su
Altermagnets combine compensated magnetic order with momentum-dependent spin splitting, which makes them promising for future spintronic and magnonic applications, but their macroscopic responses can be strongly reduced by domain averaging. In hexagonal $ \alpha$ -MnTe, three symmetry-related in-plane Néel-vector orientations and their time-reversal counterparts form six magnetic domain states, complicating both magnetic structure determination and measurements of the chiral magnon response. Using single-crystal neutron diffraction, we show that an in-plane field applied along the $ [-1,1,0]$ direction produces a common magnetic domain orientation that saturates near $ \mu_0H=2$ T. A constrained refinement of 61 nuclear and magnetic reflections collected at 2 K and 2 T yields $ \mathbf{M}\parallel[1,1,0]$ , an ordered moment of $ 4.62(8)~\mu_\mathrm{B}$ per Mn, and an orientational domain population at $ r_A:r_B:r_C=0.97:0.03(5):0$ that is compatible with a nearly complete alignment of orientational domains. Furthermore, an abnormal behaviour in the temperature dependence of the selected reflections is observed in 60-88 K, its microscopic origin is discussed within the context of possible intrinsic piezomagnetic or magnetoelastic effects. Because unpolarized diffraction neither distinguishes domain repopulation from continuous Néel-vector rotation nor resolves time-reversal antiphase domains, the field-prepared state is a near-single-orientation state rather than a truly single-domain state. This non-contact domain control provides a practical complement to strain and field-cooling approaches for preparing well-defined magnetic states in bulk $ \alpha$ -MnTe.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
12 pages, 6 figures, 3 tables
Controlling the Atomic Reconstruction in Twisted MoSe$_2$/WSe$_2$ with a Monolayer hBN Spacer
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-12 20:00 EDT
Johannes Figueiredo, Kaiyuan Chen, Aubrey Penn, Mirco Troue, Sebastian Loy, Kenji Watanabe, Takashi Taniguchi, Frances M. Ross, Julian Klein, Alexander W. Holleitner
Twisted van der Waals heterobilayers are a promising material platform for studying collective exciton many-body phenomena, but near-aligned structures often exhibit a local, anisotropic atomic reconstruction that compromises lateral homogeneity. The present study describes how atomic-scale rearrangement in adjacent regions of hBN-encapsulated, near-aligned MoSe$ _2$ /WSe$ _2$ heterobilayers is controlled by the presence of a mono- or bilayer hBN spacer between the two monolayers. High-angle annular dark-field STEM directly resolves the atomic alignment in both layers and shows that the spacer suppresses the reconstruction and strongly increases the structural uniformity of the heterobilayers. 4D-STEM quantitatively maps local rotation, dilation, and heterostrain, revealing that the separated regions remain consistent with rigid moiré superlattice simulations, whereas without the spacer the structural parameters have two to three times broader distributions. By suppressing reconstruction, ultrathin hBN spacers therefore provide an effective route to enhance lattice homogeneity in MoSe$ _2$ /WSe$ _2$ heterobilayers targeting collective excitonic and optoelectronic phenomena.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
A new device for live cell imaging of biological samples under in-plane shear
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-12 20:00 EDT
Sidharth Kumar Das, Lyova Mamoyan, Eberhard Bodenschatz, Stefano Villa
The effect of mechanical stresses and deformations upon the behavior and properties of cells and tissues is a topic of paramount interest in the field of biophysics. Its understanding is essential for deepening our comprehension of cellular responses to environmental stimuli, with implications in fields ranging from embryogenesis to tumor development. For boosting the understanding in this field, it is important to develop devices for the application of simple deformations in order to probe the cellular response to the basic mechanical transformations. While a number of stretching devices have been developed, in-plane shearing deformation has been little investigated. Here, a new device is introduced that allows the application of homogeneous in-plane shear upon a cell monolayer while imaging the sample with a commercial optical microscope. A description of the faced experimental challenges is reported and a full characterization is presented. It is demonstrated the capability of the device to apply reproducible, controlled and homogeneous shear of both single cells and confluent cellular monolayers.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph), Instrumentation and Detectors (physics.ins-det)
Accepted by Biophysics Reviews
The effects of non-stoichiometric lattice structure and secondary phase α-Fe2O3 on modifying the magnetic, electrical, and magneto-electric properties of Eu doped BaFe12O19 hexaferrite
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-12 20:00 EDT
Gara Kishor, R. N. Bhowmik, P. D. Babu
The Ba-atoms in BaFe12O19 were substituted by Eu-atoms to prepare the material of composition Ba1-xEuyFe12O19. The Eu atoms occupied at the sites of Fe atoms. The atomic ratio of Eu/Ba were varied from 0 to 0.33 to control the secondary phase (hematite) and M-type hexaferrite. Raman spectra provided complimentary support for a systematic increase of the hematite phase on increasing the Eu/Ba ratio. X-ray photoelectron spectroscopy informed the presence of oxygen deficiency and surface defects, and charge state of Ba and Fe/Eu ions close to +2 and +3, respectively. The material showed direct optical transitions with band gap in the range of 2.25-3.09 eV. The increase of Eu/Ba ratio systematically increased the saturation magnetization from 84.44 emu g-1 to 57.68 emu g-1 at 3 K and 67.09 emu g-1 to 43.42 emu g-1 at 300 K, along with remarkable enhancement of the coercivity (914- 3656 Oe at 3 K and 1996-4862 Oe at 300 K). Electrical conductivity increased from 10-11-10-10 Sm-1 at 30 K to 10-5 -10-4 Sm-1 at 300 K. The electrical conductivity analysis reveals the Efros-Shklovsky-type variable-range hopping mechanism at the low-temperature region, whereas the Mott variable range hopping mechanism is applicable near to room temperature. The analysis of current-voltage characteristics provided electrode to sample interfacial barrier height of 0.27-0.74 eV. The material exhibited novel magneto-electronic properties (bi-stable electronic switching and its transformation in the temperature scale, magnetoresistance and magnetoelectric coupling) which are highly useful for spintronic devices. This work demonstrates that controlled Eu/Ba atomic ratio in the stoichiometric and non-stoichiometric lattice structure could be an effective strategy to widely tune the magnetic, optical and magneto-electronic properties in M-type Ba hexaferrite material.
Materials Science (cond-mat.mtrl-sci)
manuscript, 17 figures, 6 tables
Graph-theoretic framework for semi-Markov networks: transient and stationary occupation probabilities, hitting times and weak ergodicity breaking
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-12 20:00 EDT
Semi-Markov networks provide a natural framework for describing stochastic transitions between coarse-grained states with non-exponential dwell times, with applications ranging from biophysics and neuroscience to epidemiology and finance. Here, it is shown that finite semi-Markov networks admit explicit combinatorial representations of their Laplace-transformed occupation probabilities and hitting-time distributions as sums over weighted spanning trees and forests of an augmented graph. These representations yield asymptotic results, including a generalization of the Markov Chain Tree Theorem to semi-Markov networks, in which the rate constants replaced by pseudo-rates given by the inverse mean sojourn time weighted by the exit probability through this channel, as well as the long-time scaling of hitting-time survival probabilities in the presence of infinite-mean sojourn times. They also extend recently derived combinatorial formulas for hitting-time moments to the semi-Markov setting. In particular, the mean hitting-time formula coincides with that of a Markov network with the corresponding pseudo-rates, which also yields a short proof of the constancy of Kemeny’s constant for finite-mean semi-Markov networks. Finally, we use the same framework to show that weak ergodicity breaking occurs generically for time-additive state observables that are nonconstant on the support of the limiting distribution in heavy-tailed semi-Markov networks.
Statistical Mechanics (cond-mat.stat-mech), Probability (math.PR)
43 pages, 4 figures
Latin squares as a model of perfect mixing of high-entropy alloys
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-12 20:00 EDT
The structure of high-entropy alloys, which include 5 or more components in equimolar proportions, is proposed to be described in the mathematical language of Latin squares. This model is fundamentally discrete and allows for a quantitative description of ideal mixing, in which any given alloy element is guaranteed not to have an identical element as its nearest neighbor. For the two-dimensional case, the model possesses four axes of translational symmetry, which makes it possible to tile the plane with a single Latin square and, based on the properties of this square, describe the properties of macroscopic material samples. The model makes it possible to make quantitative estimates of the suitability of a particular atomic structure (configuration) for implementation in a perfectly mixed high-entropy alloy with maximum mixing entropy. A condition has been obtained for acceptable fluctuations in the concentration of components at which the thermodynamic stability of the alloy is maintained. The possibility of identifying superstructures in high-entropy alloys based on group theory, as applied to the description and construction of Latin squares, is discussed. Based on the proposed model, the probability of forming a multicomponent alloy with ideal mixing is estimated. For a five-component alloy, this probability is no more than 2.6\ast10^{-10}.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
12 pages, 5 figures
How Fluctuations Control Chiral Symmetry Breaking in Reacting Mixtures of Chiral Molecules
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-12 20:00 EDT
Leonardo Silva-Dias, Christoph A. Weber
The pronounced chiral asymmetry of biomolecules is a defining feature of living systems, yet the mechanisms by which such asymmetry emerged remain unresolved. Chiral symmetry breaking may have occurred under prebiotic conditions in systems with sufficiently small molecular populations for intrinsic fluctuations to play an important role. Here, we investigate how finite-population fluctuations affect chiral-state selection, the characteristic time for symmetry breaking, and stochastic switching between chiral states in a system driven by autocatalysis and mutual antagonism. We determine how these dynamical processes scale with particle number and derive an analytical expression for the probability of selecting either chiral state as a function of the initial enantiomeric bias. We further calculate the mean selection time for different initial biases and show that, for weak mutual antagonism, fluctuations can induce transitions between opposite chiral states. These results characterize how finite-population fluctuations control both the emergence and stability of molecular chirality in autocatalytic chemical systems.
Soft Condensed Matter (cond-mat.soft)
Giant geometric nonlinear transport in inhomogeneously strained Bi$_2$Se$_3$ single crystalline slabs
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-12 20:00 EDT
Igor Veremchuk, Pavlo Makushko, Anita Guarino, Muhammad Waqee Ur Rehman, Rosalba Tatiana Fittipaldi, Tobias Kosub, Alexej Pashkin, Fabian Ganss, Oleg A. Petrenko, Proloy T. Das, Rui Xu, Rhonald Burgos Atencia, Debottam Mandal, Antonio Vecchione, Carmine Ortix, Denys Makarov
Electrical transport in non-centrosymmetric materials exhibits a nonlinear conductivity tensor component that generates second-harmonic voltages in response to applied electric fields. Harnessing this effect is essential for developing zero-threshold electromagnetic energy harvesters and broadband frequency upconverters, both of which require maximizing the nonlinear responsivity. Here, we demonstrate that inhomogeneously strained macroscopic slabs of the topological insulator Bi$ _2$ Se$ _3$ achieve a record-high nonlinear responsivity of $ 10^4,\mu$ m/V: a six orders of magnitude boost compared to its thin-film counterparts. We attribute this giant enhancement to a classical geometric nonlinear transport effect, which is driven by complex strain gradients within the bulk material. Notably, a similar geometric mechanism known as geometric nonlinear Hall was previously observed only in microscale-patterned structures. Our findings establish macroscopic strain engineering as a powerful route to enhance nonlinear transport, with immediate relevance to a broad class of layered systems, including transition metal dichalcogenides and moiré heterostructures.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
11 pages, 4 figures
Altermagnetic Control of Charge-4e Superconductivity
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-12 20:00 EDT
Yan-Guang Yue, Jie Lou, Yan Chen
We present, to our knowledge, the first theoretical realization of an independent charge-4e phase in a two-dimensional classical array of conventional superconductors coupled through altermagnetic junctions. Tuning the altermagnetic splitting suppresses the leading single-pair tunneling harmonic while retaining strong double-pair coupling, producing a finite charge-4e region between staggered and uniform charge-2e states. Using the complete temperature-dependent microscopic Josephson spectrum, we find short-range ordinary pair correlations alongside algebraic coherence of pairs of Cooper pairs. Berezinskii–Kosterlitz–Thouless scaling and a half-flux response further identify the charge-4e phase. Our results establish altermagnetism as a microscopic means to select between ordinary and composite superconducting coherence.
Superconductivity (cond-mat.supr-con), Statistical Mechanics (cond-mat.stat-mech)
Ferroelectric Domain-Wall Motion, Stability, and Frequency Responses under Different Screening-Charge Conservation Laws
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-12 20:00 EDT
We analyze ferroelectric domain wall motion, shape, and internal structure arising from coupling between polarization and screening charge. Universal cases are organized by electrical boundary conditions, charge conservation and dynamics, and polarization free energy. We consider exposed surfaces, interfaces beneath a dielectric layer and top electrode, and interfaces with a blocking mixed ionic-electronic conductor. Screening occurs through local exchange, exchange with lateral transport, or strictly conserved redistribution. Analytical derivations and finite-depth calculations establish screening drag, velocity branches, and conditions for spatial instability. For an isolated wall joining differently compensated domains, strict surface conservation and zero far-field current exclude steady translation of the screening profile, while allowing transient displacement, finite-sample arrest, and charge-balanced structural changes. Conservation also constrains long-distance transport around a moving junction in an adjoining conductor. Large-field simulations in the top-electrode geometry reveal nonlinear corrugation, transfer toward longer wavelengths, and coupled polarization rotation. First-order polarization energetics allow two interphase fronts enclosing a paraelectric core; multiaxial polarization permits wall rotation and competing intermediate ferroelectric domains. A driven structural-screening reduction supports stable periodic behavior. Reduced-variable diagrams summarize motion and structural regimes, while BaTiO3 and BiFeO3 examples connect them to material thermodynamics. Small-signal analysis distinguishes displacement, polarization, and electrostatic response functions. These results provide a framework for wall dynamics and structural transitions under different driving and screening conditions.
Materials Science (cond-mat.mtrl-sci)
Parametric Glassiness in Graphene-based Electronic Lévy Glass
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-12 20:00 EDT
Caue N. da Silva, Diego B. Fonseca, Adauto J. F. de Souza, Antônio M. S. Macêdo, Luiz Felipe C. Pereira, Anderson L. R. Barbosa
Complex disordered conductors can display highly structured and parameter-sensitive transport even in the absence of a thermodynamically stable glass phase. Overlap distributions originally developed for replica symmetry breaking (RSB) provide a useful diagnostic of this organization, provided that their interpretation is distinguished from the equilibrium Parisi construction. In this study, we report RSB-like overlap phenomenology and parametric mesoscopic glassiness in a graphene-based electronic Lévy glass, a device that mimics optical phenomena via electronic processes. By tuning the Fermi energy, we can control the number of propagating wave modes and observe reentrant changes from narrowly centered to broad or bimodal overlap distributions. The phenomenology is observed in both graphene-based and conventional two-dimensional electron-gas electronic Lévy glasses, indicating its generality. Sample-resolved overlap distributions show that the effect is intrinsic to each disorder landscape, whereas the normalized conductance variance shows that the growth of the absolute variance is mainly caused by the increasing mean conductance. We therefore interpret the overlap as a measure of correlation among hierarchically organized transport pathways and the reentrant behavior as evidence of pinning, parameter-induced reorganizations, and mesoscopic chaos in coherent transport.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Statistical Mechanics (cond-mat.stat-mech)
A new approach to the Kondo effect: sophomore’s dream function and Lee-Yang zeros
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-12 20:00 EDT
We develop an analytical approach to the Kondo problem based on an effective partition function that generalizes the sophomore’s dream integral. The Kondo crossover is represented as a passage through an approximately equidistant ladder of its Lee-Yang zeros in the complex plane, rather than as a singularity on the real axis. Summation over this ladder yields the Gamma function $ \Gamma(\alpha + T_K/(2 \pi T))$ as the universal crossover backbone, where the offset $ \alpha =1/2$ is fixed by the Friedel sum rule. The Euler-Maclaurin expansion connects the discrete zero structure to the Nozieres Fermi-liquid theory through Bernoulli numbers. A two-cutoff formula provides a compact, essentially one-parameter description of the full crossover in terms of a temperature-space Fano lineshape which is a thermal average of the energy-space Fano resonance observed in STM. Drift corrections are treated. The approach extends to $ \mathrm{SU}(N)$ Coqblin-Schrieffer, underscreened and Anderson impurity models, and Kondo lattices.
Strongly Correlated Electrons (cond-mat.str-el)
7 pages
Physics Letters A 598 (2026) 132238
Dislocation mediated twin boundary faceting in $β$-Sn
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-12 20:00 EDT
John Israel, Ian Chesser, Khanh Dang, Vinamra Agrawal
Grain boundaries (GBs), including twin boundaries (TBs), play a critical role in plastic deformation by interacting with dislocations. The deformation and strengthening mechanisms in $ \beta$ -Sn are of significant interest because Sn-based alloys are widely used as solder materials. Recent experiments have shown deformation-induced faceting in $ \beta$ -Sn arising from twin-dislocation interactions. Using molecular dynamics (MD) simulations informed by a recently developed machine-learned interatomic potential (MLIP), we demonstrate a $ \langle c\rangle$ dislocation-absorption mediated faceting reaction along $ (301)$ TBs in $ \beta$ -Sn in which facet length grows with the number of absorbed dislocations. We show that the predicted facet length is consistent with isotropic elasticity theory only when the disclination character of the asymmetric twin facet is taken into account. We discuss analogies to faceting reactions in other low symmetry metals and hypothesize that the ubiquity of $ (301)$ twins in $ \beta$ -Sn stems from their ability to grow rapidly through a forest of dislocation obstacles.
Materials Science (cond-mat.mtrl-sci)
Shear-driven arrest of dip-coating film entrainment
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-12 20:00 EDT
Theo Witkamp, Stéphane Zaleski, Federico Toschi
A plate withdrawn from a bath of partially wetting liquid entrains a film above a critical velocity. Here, we show that this critical threshold can be substantially increased by the presence of a laminar gas flow opposed to the plate velocity that exerts a tangential shear stress on the liquid-gas interface. Using two-phase immiscible Navier-Stokes simulations and confining the gas to a narrow channel, we derive a closed-form expression for the interfacial stress, which combined with lubrication theory relates the thickness of the film and the contact line velocity to the applied shear stress. As the gas velocity is increased, the film thins and the contact line velocity slows down, until the imposed shear overcomes the drag of the moving plate and entrainment is arrested. As in the quiescent case, the velocity mismatch between plate and contact line is independent of the plate velocity and is set by the applied shear alone. We find that one set of varying gas flow simulations, with constant critical plate velocity, therefore determines the critical gas flow for every smaller plate velocity.
Soft Condensed Matter (cond-mat.soft), Fluid Dynamics (physics.flu-dyn)
6 pages, 6 figures
Arrested phase separation and amorphous patterns in charged binary fluids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-12 20:00 EDT
Logan H. Grant, Ana Bensabat, Eva Pospivsilova, Joost de Graaf, Alexander Morozov, Giuseppe Negro, Ciprian G. Pruteanu, Tyler N. Shendruk, Davide Marenduzzo
Frustration generated by competing interactions can stabilise patterns with tunable lengthscales which evade indefinite coarsening and macroscopic phase separation. Here we investigate a charged binary fluid in which the tendency toward phase separation is opposed by screened electrostatic repulsion. Combining analytics and numerical simulations, we identify a regime of arrested phase separation characterised by finite-wavelength instability. The resulting states include droplet and labyrinthine phases in two dimensions, and droplets, concentric shells and tubular structures in three dimensions. Surprisingly, some of these structures are amorphous morphologies that emerge reproducibly from different initial conditions. Free-energy estimates suggest that these disordered structures may be thermodynamically stabilised by frustration, rather than being kinetically trapped. Our results identify a simple mechanism through which the competition between phase separation and screened electrostatics can generate equilibrium amorphous microphases with glassy features.
Soft Condensed Matter (cond-mat.soft)
13 pages, 13 figures
Scalene Yang-Baxter triples realize all nearest-neighbour Hamiltonians with global additive symmetries
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-12 20:00 EDT
Pramod Padmanabhan, Somnath Maity, Akash Sinha, Vladimir Korepin
We establish that bond Hamiltonian densities, up to local difference terms whose sum vanishes under periodic boundary conditions, lying in the commutant of bond operators, $ w_j\pm w_{j+1}$ , is a necessary and sufficient condition for a one-dimensional nearest-neighbour Hamiltonian to conserve a uniform or staggered sum of the one-site operators $ w_j$ . Starting from these local commutants, we show that every such Hamiltonian and its conserved charge can be obtained from monodromy matrices constructed using regular and non-regular members of scalene Yang-Baxter triples. The results hold on periodic chains of length $ L\geq3$ , with even length required in the staggered case. The results do not require translation invariance, and hence the interaction on each bond can be chosen independently from the full corresponding commutant. Our representation-independent construction applies in arbitrary finite local dimension and exhausts the Hamiltonians with either prescribed additive symmetry, without requiring ordinary Yang-Baxter integrability. We illustrate the construction with spin-$ \tfrac12$ and spin-1 systems and discuss its relation to the double-commutant theorem. Classifying the one-site generators $ w$ and their associated bond commutants provides a route to classifying such Hamiltonians with additive conserved charges.
Statistical Mechanics (cond-mat.stat-mech), High Energy Physics - Theory (hep-th), Mathematical Physics (math-ph), Exactly Solvable and Integrable Systems (nlin.SI)
24 pages
Improved screening of doped ZrO$_2$ catalysts for CO$_2$ hydrogenation from graph-based machine learning
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-12 20:00 EDT
Karsten Walz Jensen, Mie Andersen, Raffaele Cheula
Dopants can tune the activity of zirconia-based CO$ _2$ hydrogenation catalysts through changes in adsorbate and transition-state (TS) energetics. Computing these quantities with density functional theory (DFT) becomes expensive when several dopants, reaction intermediates, and TSs must be screened. Here, we further develop the graph-based machine learning method Wasserstein Weisfeiler-Lehman Gaussian Process Regression (WWL-GPR): we introduce additional electronic-structure and local-environment features relevant for oxide surfaces and use the resulting model to predict adsorption and TS energies on ZrO$ _2$ (101) surfaces doped with Al$ ^{3+}$ , Cd$ ^{2+}$ , Ga$ ^{3+}$ , In$ ^{3+}$ , and Zn$ ^{2+}$ . Adsorbate-surface structures are represented as attributed graphs that combine bonds connectivity and features. We benchmark WWL-GPR against thermodynamic scaling relations (TSR) for reaction intermediates and Bronsted-Evans-Polanyi relations (BEP) for TSs, and then propagate the predicted energies to microkinetic CH$ _3$ OH-yield estimates. WWL-GPR consistently improves the prediction of reaction intermediate energetics relative to linear scaling approaches and provides TS estimates that are competitive with BEP-based models. These improvements become especially relevant when the predicted energetics are propagated through the reaction network. Microkinetic calculations show that WWL-GPR-derived energies give CH$ _3$ OH yields closer to DFT-derived yields than the linear-relation workflow. Degree-of-rate-control analysis links the activity errors to dopant-dependent rate-controlling steps, including HCOO\ast formation, H$ _2$ COOH\ast dissociation, and H$ _3$ CO\ast formation. These results support WWL-GPR as a data-efficient surrogate for connecting atomistic energetics with catalyst-screening observables on doped oxide surfaces.
Materials Science (cond-mat.mtrl-sci)
Replica Transition at Measurement-Altered Ising Criticality
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-12 20:00 EDT
Kabir Khanna, Sara Murciano, Romain Vasseur
Performing measurements on gapless quantum ground states can give rise to new universal phenomena, whose origins remain poorly understood even for the paradigmatic Ising critical point. Replica methods offer a natural framework to study such post-measurement ensembles, with the replica limit $ Q\to 1$ describing physical Born-averaged observables. Here we show that, for the monitored critical Ising chain, the replicated post-measurement ensemble of states itself undergoes a phase transition precisely at the physically relevant replica limit $ Q \to 1$ , preventing standard replica treatments. We use boundary conformal field theory (BCFT) methods to explain the underlying mechanism of this transition. Our methods yield a perturbative analytic calculation of the universal $ O(1)$ constant in the Shannon entropy of the measurement record, previously known only numerically. We also apply our tools to study measurement-averaged spin correlators, providing a unified description of the universal properties of measurement outcomes and post-measurement states in the critical Ising chain.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
22 pages, 2 figures
Phononic Frequency Combs in Twisted Bilayer Transition Metal Dichalcogenide Heterostructures from First Principles
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-12 20:00 EDT
Phononic frequency combs are equidistant spectral ladders generated when a driven vibrational mode transfers energy to an autoparametrically excited subharmonic mode through anharmonic intermode coupling. In previous studies, the coupling strength governing this energy transfer has typically been treated as a free parameter, extracted from a fabricated device, or adopted from an earlier calculation for a specific mode pair. As a result, whether a given crystal can support a phononic frequency comb, and the drive strength required to generate it, has not been predictable a priori. Here we obtain the complete parameter set from density functional theory. Twisted bilayers of \MoSSe{} and \MoSMoSe{} at the commensurate angle $ 21.787^{\circ}$ adopt space group $ P3$ in a 42-atom \rootseven{} moiré supercell. The second-order force constants provide the mode frequencies; the third-order constants provide the linewidths through the Boltzmann transport equation and hence the quality factors; and the same third-order tensor projected onto the phonon eigenvectors of a chosen mode pair provides the anharmonic couplings $ \kt$ and $ \kss$ . Both bilayers constitute a mode pair within $ 0.8%$ of the $ 2!:!1$ resonance with $ \omega_1/\omega_2 = 1.9923$ in \MoSSe{} and $ 1.9943$ in \MoSMoSe{}. By integrating the resulting two-mode equations, both modes generate combs through a discontinuous transition: at $ 701,\fth$ in \MoSSe{} the envelope variance rises from $ 2.1\times10^{3}$ to $ 1.37\times10^{4}$ and the tooth count of mode 1 from 7 to 16 within a single $ 5,\fth$ increment, identifying the onset as subcritical. The spectral entropy peaks \emph{before} this jump, at $ 341,\fth$ . The two compounds carry comparable coupling, differing by a factor of $ 1.2$ . However, the comb excitation threshold is set by the quality-factors of signal modes: $ Q_2 = 672$ for \MoSSe{} and $ Q_2 = 3844$ for \MoSMoSe{}.
Materials Science (cond-mat.mtrl-sci), Pattern Formation and Solitons (nlin.PS)
13 pages, 4 figures
Robust Golden Ratio universality as a consequence of a circulant symmetry
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-12 20:00 EDT
Luka Paljk, Johannes Schmidt, Vladislav Popkov
We find a robust scenario for the emergence of the Golden Ratio (GR) dynamical universality class, characterized by the dynamical exponent $ z \equiv \varphi=\frac{1}{2}(1+\sqrt{5})$ . Previously, its emergence required fine-tuning of system parameters. Here, the GR universality class appears generically in a wide class of Markov processes as a consequence of a global, circulant symmetry of the flux Jacobian. This symmetry leads to GR universality in systems where the total number of conservation laws is odd and larger than three. We introduce a multilane exclusion process with Bernoulli stationary measure as a minimal, parameter-free model, which features GR universality for all conserved modes, most of which are doubly degenerate. Our predictions, based on mode-coupling theory generalized to treat degenerate conserved modes, are corroborated by large-scale Monte Carlo simulations.
Statistical Mechanics (cond-mat.stat-mech), Cellular Automata and Lattice Gases (nlin.CG)
6+5 pages, 3 figures
Doubly Metastable Synthesis for Accelerated Quantum Materials Discovery
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-12 20:00 EDT
Kyuho Lee, Berit H. Goodge, Soonhyun Kwon, Yash Anand, Theo Manev, Maximilien F. Debbas, Weiliang Luo, Takehito Suzuki, Heather J. Kulik, Joseph G. Checkelsky
New physics emerges from new materials, which in turn rely on the development of new synthesis techniques. Identifying the enlargement of metastable synthesis window as enabling for realizing novel materials, we develop diffusion-activated epitaxy, a technique which combines two metastable synthesis methods of diffusion and epitaxy. We observe that within a narrow window of investigated synthesis space we can experimentally identify the stabilization of four distinct phases, three of which show X-ray diffraction and scanning transmission electron microscopy characterization data that are incompatible with the crystal structures registered in experimental and computational inorganic structure databases. These results suggest an enlarged metastable synthesis window is enabled by this synthesis approach, identifying doubly metastable synthesis as a promising method for exploration of quantum materials.
Materials Science (cond-mat.mtrl-sci)
Potential energy release rate for solids with bounded domains during evolutions involving changes to boundaries and boundary data
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-12 20:00 EDT
Mrityunjay Kothari, Sayaka Kochiyama, Haneesh Kesari
We investigate the rate of change of equilibrium potential energy for nonlinear elastic solids undergoing evolutions that may involve changes in body geometry, material properties, applied tractions, and prescribed displacements. We represent such an evolution by a one-parameter family of variational problems and identify a class of these families for which the potential-energy release rate is well defined. Particular attention is given to the formulation of the potential energy at each evolution state: each constituent variational problem must yield the appropriate equilibrium state, while its equilibrium value must also correctly represent the physical change in potential energy between states. Within this framework, we derive a closed-form expression for the potential-energy release rate for solids with bounded domains, allowing for spatially nonuniform material evolution, sharp material interfaces, and evolving boundary geometry and prescribed boundary data. The expression is determined entirely by the equilibrium solution at the state under consideration and by the quantities prescribing the local evolution, so neighboring equilibrium problems need not be solved. Finally, we apply the result to the extension of a notch in a two-dimensional elastic body and show that the resulting potential-energy release rate reduces to the classical $ J$ -integral.
Soft Condensed Matter (cond-mat.soft)
53 pages, 6 figures
Necessary conditions for benchmarking next-generation AI in materials discovery
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-12 20:00 EDT
Daniel E Widdowson, Tatiana V Kurlina, Olga D Anosova, Vitaliy A Kurlin
Current AI predicts materials by speeding up energy minimisation and training on large databases. However, scaling data generation prevents manual analysis by domain experts. If novelty is evaluated by chemical compositions or traditional representations in Crystallographic Information Files, or standard structure matchers based on manually chosen thresholds, one can easily generate millions of new'' compositions or files without discovering truly novel materials. This paper uses a hierarchy of crystal invariants to continuously trace and quantify structural novelty based on the new mathematical definition of a crystal structure and asymptotic guarantees for invariant descriptors. The invariant-based analysis through cascade computations on a modest computer exposes the unexpected scale of duplication in the world's largest materials databases, shown here in the high-profile case of GNoME datasets. To prevent current embarrassment of over-prediction’’, we propose necessary conditions for next-generation AI that should be automatically enforced before claiming any new materials.
Materials Science (cond-mat.mtrl-sci), Metric Geometry (math.MG)
44 pages, 16 figures
Research Square
Non-Abelian Quantum Metric Governing Topological Boundary-Mode Localization
Article | Topological matter | 2026-10-11 20:00 EDT
Jin-Xin Hu, Xinglei Ma, Kam Tuen Law
The presence of localized boundary modes is an unambiguous hallmark of topological quantum matter. While these modes are typically protected by topological invariants such as the Chern number, here we demonstrate that the quantum metric length (QML), a quantity inherent in multi-band topological systems, governs the spatial extent of flat-band topological boundary modes. We introduce a framework for constructing topological flat bands from degenerate manifolds with large quantum metric and find that the boundary modes exhibit two sequential phases of spatial behaviors: a conventional oscillatory decay arising from bare band dispersion, followed by another exponential decay controlled by quantum geometry. Crucially, the QML, derived from the non-Abelian quantum metric of the degenerate manifolds, sets a lower bound on the spatial spread of boundary states in the flat-band limit. Applying our framework to concrete models, we validate the universal role of the QML in shaping the long-range behavior of topological boundary modes. Furthermore, by tuning the QML, we unveil extraordinary non-local transport phenomena, including QML-shaped quantum Hall plateaus and anomalous Fraunhofer patterns. Our theoretical framework paves the way for engineering boundary-mode localization in topological flat-band systems.
Research Square:rs-11232671 (2026)
Posted on Research Square and Under Review at Nature Portfolio
Physical sciences/Physics/Condensed-matter physics/Topological matter, Physical sciences/Physics/Condensed-matter physics/Electronic properties and materials