CMP Journal 2026-05-04
Statistics
Nature Materials: 1
arXiv: 50
Nature Materials
Observation of coherent ferron emission and propagation
Original Paper | Ferroelectrics and multiferroics | 2026-05-03 20:00 EDT
Jeongheon Choe, Taketo Handa, Chun-Ying Huang, André Koch Liston, Jordan Cox, Jonathan Stensberg, Yongseok Hong, Daniel G. Chica, Ding Xu, Fuyang Tay, Samra Husremovic, Vinicius da Silveira Lanza Avelar, Eric A. Arsenault, Zhuquan Zhang, James McIver, Dmitri N. Basov, Milan Delor, Xavier Roy, X.-Y. Zhu
Ordered phases give rise to collective modes and quasiparticles, such as spin waves and magnons emerging from magnetic order. Extending this paradigm to ferroelectrics suggests the existence of polarization waves and their fundamental quanta, ferrons. A coherent ferron–that is, a polarization wave–modulates the magnitude of the electric polarization and is thus an amplitude (Higgs) mode of the ferroelectric order. Here we observe coherent ferrons from the pulsed laser excitation of van der Waals ferroelectrics, NbOI2 and WO2Br2. We demonstrate two complementary manifestations of coherent ferrons: intense narrow-band terahertz emission at the ferroelectric transverse optical phonon frequency, and uniaxial propagation along the polar axis as hyperbolic phonon polaritons with exceptionally long coherence times. These long-lived, uniaxial and dipole-carrying polarization waves may find applications in narrow-band terahertz emission, ferronic information processing and coherent electric control.
Ferroelectrics and multiferroics, Ultrafast photonics
arXiv
Locality versus Fock-space structure in East-type models
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-05-04 20:00 EDT
Local kinetic constraints in quantum many-body systems can generate slow dynamics or complete many-body localisation. Here we focus on a modification of the quantum East model: Inspired by random matrix theory, we randomise the connectivity in Fock space (rendering it nonlocal in real space) while preserving its organisation into neighbouring magnetisation sectors. We find that there is still a transition between two distinct phases, one delocalised and the other localised. We conclude that, for East-type constrained models, the essential ingredient is the structure of the graph in Fock space rather than geometric locality of spin flips.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech)
Criticality on Rényi defects at (2+1)$d$ O(3) quantum critical points
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-05-04 20:00 EDT
Yanzhang Zhu, Zhe Wang, Meng Cheng, Zheng Yan
At a quantum critical point, the universal scaling behavior of Rényi entanglement entropy is controlled by the universality class of the codimension-two Rényi (or conical) defects in the infrared theory. In this work we perform a systematic study of critical correlations along Rényi defect lines in (2+1)d quantum spin models realizing quantum phase transitions described by the O(3) Wilson-Fisher universality class, using large-scale quantum Monte Carlo simulations. We present numerical evidence that, for a fixed Rényi index $ n$ , there exist multiple Rényi defect universality classes, with distinct critical exponents for the O(3) order parameter on the defect. These universality classes are realized by choosing microscopically different entanglement cuts in lattice models, which we classify as ordinary, special and extraordinary according to their relation to surface criticality. For the extraordinary entanglement cut, we further find evidence for a phase transition on the defect as a function of the Rényi index. Our results highlight the key role of defect universality classes in determining the universal scaling of Rényi entropy, and provide a framework for understanding the previously observed dependence of Rényi entropy scaling on microscopic lattice details.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech), High Energy Physics - Theory (hep-th), Quantum Physics (quant-ph)
7+4 pages; 4+6 figures
Graph theoretic derivation of mutual linearity for transient probabilities and hitting time distributions in Markov networks
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-05-04 20:00 EDT
Julian B. Voits, Ulrich S. Schwarz (Heidelberg University)
For irreducible, time-homogeneous Markov networks, mutual linearity has recently been established for both occupation probabilities and network currents in the stationary regime as well as in the non-stationary regime in Laplace space. The derivation of this property for the stationary distribution utilized the Markov-chain tree theorem, which also allows for an explicit combinatorial expression of the response ratios under variation of a single transition rate. The extension of this result was proven at the trajectory level by employing the Doob-Meyer decomposition. By employing the all-minors matrix-tree theorem, we show that this property also follows from a graph theoretic formulation and derive explicit combinatorial expressions for the non-stationary response ratios. The stationary result follows as the long-time limit and we also show that the small-time asymptotics are entirely determined by minimal path distances in the underlying graph. Finally we use the graph theoretic approach to prove that mutual linearity also extends to hitting time densities.
Statistical Mechanics (cond-mat.stat-mech), Probability (math.PR)
Revtex, 14 pages
Demonstration of a fermion Quadrupling Condensate via Quantum Monte Carlo Simulation
New Submission | Superconductivity (cond-mat.supr-con) | 2026-05-04 20:00 EDT
Alexandru Golic, Egor Babaev, Johan Carlström
Fermionic condensation typically occurs via pairing. In recent decades, however, a fundamental question has emerged: whether alternative forms of order exist, such as condensates of fermion quadruplets. These states–including charge-4e" superconductors and charge-0” counterflow condensates–lie beyond the standard Bardeen-Cooper-Schrieffer framework, and require strong fluctuations and correlation effects that invalidate the BCS mean-field description. This makes the problem notoriously difficult to study numerically at a microscopic level, as it involves both strong interactions and the fermionic sign problem. Here, we present a microscopic fermionic model featuring correlated hopping that significantly mitigates the sign problem, enabling rigorous Monte-Carlo-based analysis. Using large-scale simulations, we demonstrate the existence of a fermion-quadrupling condensate with a transition temperature comparable to the hopping energy scale. These results provide direct numerical evidence for quartic fermionic order in a microscopic system and suggest that these exotic states are also experimentally accessible in ultracold atomic gases.
Superconductivity (cond-mat.supr-con), Quantum Gases (cond-mat.quant-gas)
9 pages, 4 figures
Data-Driven Modelling to predict forest fire spread in the Patagonian region in Argentina
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-05-04 20:00 EDT
Lucas Becerra, Monica Malen Denham, Alejandro B. Kolton, Karina Laneri
Wildfires are among the most severe disturbances affecting forest ecosystems, with over 50,000 hectares burned in Patagonia, Argentina, during 2025 alone. This study implements a Reaction-Diffusion-Convection (RDC) model to simulate wildfire spread in the Steffen and Martin Lakes area, a region severely impacted by fires. By integrating high-resolution maps of slope, wind velocity, and vegetation, we conducted three computational experiments of increasing complexity to simulate fire propagation across heterogeneous landscapes.
We employed a Genetic Algorithm (GA) to recover reference model parameters by maximizing the spatial overlap between simulated and reference burned areas. Subsequently, parameter estimates were refined using XGBoost to improve accuracy. Results demonstrate that the GA accurately recovers reference parameters across all scenarios, while the XGBoost fine-tuning significantly enhances accuracy in simpler cases. This integrated framework offers a systematic approach for estimating difficult-to-measure wildfire parameters, demonstrating the potential of hybrid computational methods for wildfire modeling and forest management.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Atmospheric and Oceanic Physics (physics.ao-ph)
29 pages, 8 figures
Ecological Modelling, Volume 518, August 2026, 111618
Insights into the electrorheological and electrohydrodynamic regimes in electrically driven emulsion
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-05-04 20:00 EDT
Majid Bahraminasr, Anand Yethiraj
Recently, we reported the electrorheoimaging (ERI) technique (Bahraminasr et al, 2026), and found that frequency-dependent electric field of an oil-in-oil emulsion yields two distinct regimes: a high-frequency dipolar, electrorheological (ER) regime and a low-frequency electrohydrodynamic (EHD) regime. In this work, we identify a phenomenological model to fit the results in the ER regime to a classic yield-stress fluid, and find collapse onto a master curve upon rescaling, consistent with a yield stress that grows approximately as $ E^2$ . Macroscopic small-amplitude oscillatory shear (SAOS) rheology is compared with passive microrheology employing differential dynamic microscopy (DDM), with the close agreement implying scale independence of the ER behaviour, and indicating that, unlike steady shear, SAOS measurements do not restructure these samples and probe underlying material properties. Finally, under the presence of both steady shear and electric fields in the EHD regime, the emulsion forms banded structures composed of alternating droplet-rich and droplet-depleted regions. We explore recurrence and divergence in the location of these bands: they emerge within seconds of field application and decay rapidly after the field is switched off. Using the Jensen–Shannon divergence between radial intensity profiles, we show that the driven structure loses memory on timescales of order $ 1~s$ commensurate with the timescale of the EHD convection roll. For much longer field-off intervals successive banding events become statistically independent.
Soft Condensed Matter (cond-mat.soft)
Observation of single antiferromagnetic magnon modes in the tunnelling transistors of spin-1/2 Kitaev system a-RuCl3
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-05-04 20:00 EDT
Servet Ozdemir, Mikhail Kashchenko, Kostya S. Novoselov
The small gap room temperature semiconductor a-RuCl3 which is known to undergo a Mott-Hubbard transition at low temperatures, is one of the most promising candidates for realisation of an exotic matter form, the quantum spin liquid state, which may have applications in quantum computing. Although being extensively investigated by neutron scattering techniques, electronic study of this system in form of van der Waals heterostructures has been limited to mainly graphene proximity. Here we report a systematic study of planar and tunnelling electronic properties of a -RuCl3 films, where we observe an n-type semiconducting property of a -RuCl3 films at room temperature, with a Mott insulator nature onset below 120K. In constant some of the previous studies, we focus on films of three-layer thickness and below and we find inelastic scattering features, below the Neel temperature of 7-14.5 K, some of which we attribute to single magnon modes. We believe our study electrically confirms preserved low temperature signatures of the bulk zigzag antiferromagnetic order and its single magnon modes within the previously observed continuum in atomically thin film limit. The experimental progress could be a step for future electronic characterisation of quantum spin liquid state in the vicinity of the zigzag antiferromagnetic order as well as the Majorona excitations in a-RuCl3 in tunnelling transistors.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
13 pages, 10 figures
Activated random walk exhibits self-organized criticality
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-05-04 20:00 EDT
Christopher Hoffman, Tobias Johnson, Matthew Junge, Josh Meisel
To explain the ubiquity of power laws and fractals in nature, Bak, Tang, and Wiesenfeld formulated simple conditions for a system to self-organize into a critical state. Dickman, Muñoz, Vespignani, and Zapperi postulated that the self-organized critical state matches the critical state in corresponding fixed-energy models undergoing traditional phase transitions. Although the theory has been applied broadly over the past five decades, no mathematical model has been proven to exhibit the conjectured behavior. Indeed, the originally proposed abelian sandpile model displays nonuniversal behavior stemming from its slow mixing. Marking the first result of its kind, we prove that the 1-d activated random walk model mixes quickly into a stationary state with power-law avalanches and limiting critical density that equals the critical value for the fixed-energy version.
Statistical Mechanics (cond-mat.stat-mech), Probability (math.PR)
12 pages; rigorous proofs of Theorems 1 and 2 can be found in arXiv:2406.01731 and arXiv:2501.17938, respectively
Quantized Collective Fluctuations in Correlated Fermion Systems
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-05-04 20:00 EDT
S.S. Onuchin, Ya. S. Lyakhova, L.D. Silakov, A.N. Rubtsov
Collective excitations in fermionic systems play a crucial role in determining their physical properties. An important challenge is to develop efficient theoretical approaches for describing these excitations and their coupling to fermionic degrees of freedom. In this work, we revisit the problem of quantifying the contributions of individual bosonic modes of collective fluctuations to observable properties of correlated fermion systems within the framework of the Fluctuating Local Field (FLF) method. Whereas the auxiliary field in this method was previously considered only classically, we formulate its systematic extension termed Quantum FLF (Q-FLF) that incorporates selected bosonic Matsubara modes, thus tailoring it to description of quantum collective fluctuations. As a testbed, we apply the approach to a half-filled one-dimensional Hubbard chain and compute the Green’s function, the total energy, and the antiferromagnetic susceptibility. Our results demonstrate that the proposed scheme enables an efficient and selective characterization of the contributions of individual bosonic modes. In particular, low Matsubara frequencies are found to have a quantitative impact on integrated observables such as total energy and antiferromagnetic susceptibility. At the same time, an accurate description of single-particle properties requires inclusion of higher-frequency bosonic modes.
Strongly Correlated Electrons (cond-mat.str-el)
Dilute Zn alloying in biodegradable Mg wires: microstructure, mechanical performance, and degradation behavior
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-04 20:00 EDT
Jiří Ryjáček, Leonard Hlodák, Jiří Liška, Jan Pinc, Tomáš Herma, Karel Tesař
Dilute Mg-Zn wires are of great interest for biodegradable small-bone fixation, as magnesium degradation can support bone-related processes, while low zinc additions may provide biological benefits without compromising biocompatibility. In this work, the influence of Zn content below the room-temperature solubility limit was assessed in Mg-Zn wires intended for resorbable implant applications. Mg-0.4Zn, Mg-0.6Zn, Mg-0.8Zn, and Mg-1.5Zn alloys were processed by single-step direct hot extrusion into thin wires and characterized by correlative microstructural analysis, tensile testing, bending experiments, and in vitro degradation. All compositions achieved a recrystallized fine equiaxed grain size of 5.0-5.9 um and exhibited ultimate tensile strengths of 246-256 MPa with elongations of 23-28 %. In these thin wires, Zn content had only a limited effect on grain size, tensile properties, and bending behavior, although lower-Zn alloys showed a pronounced sharp yield point. Bending was governed mainly by extrusion texture and preserved reversible plasticity through twinning and detwinning. Simulated body fluid caused rapid localized degradation and loss of mechanical integrity within 7 days, while the biologically more relevant DMEM-based medium better reflected the expected in vivo response. Together, these findings support dilute Mg-Zn wires as a simple material platform for the development of future resorbable bone fixation devices.
Materials Science (cond-mat.mtrl-sci)
29 pages, 9 figures
Low-temperature Depletion of Superfluid Density in the Absence of Galilean Symmetry
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-05-04 20:00 EDT
Viktor Berger, Nikolay Prokof’ev, Boris Svistunov
Landau theory of superfluidity associates low-temperature flow of the normal component with the phonon wind. This picture does not apply to superfluids in which Galilean invariance is broken either by disorder, porous media, or lattice potential, and the phonon wind is no longer solely responsible for depletion of the superfluid component. Based on Popov’s hydrodynamic action with anharmonic terms, we present a general theory for low-temperature ($ T$ ) dependence of the superfluid stiffness, which reproduces Landau result as a special case when several parameters of the hydrodynamic action are fixed by Galilean invariance, and validate it with numerical simulations of interacting lattice bosons. In a broader context, our approach reveals universal low-temperature thermodynamics of superfluids with an intrinsic connection between finite-$ T$ and finite-size ($ L$ ) effects implying universal scaling, $ T^{d+1}$ and $ 1/L^{d+1}$ , respectively, for a large class of thermodynamic quantities. We discuss the experimental detection of this law, and compare our prediction to the existing literature.
Quantum Gases (cond-mat.quant-gas), Statistical Mechanics (cond-mat.stat-mech)
5 pages, 2 figures. arXiv admin note: substantial text overlap with arXiv:2506.22683
Phys. Rev. Lett. 136, 166001 (2026)
Surface-Adsorbed Nanodroplets of Symmetric Diblock Copolymers Form Versatile and Stimuli-Responsive Nanostructures
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-05-04 20:00 EDT
Artem Petrov, Guillermo A. Hernández-Mendoza, Alfredo Alexander-Katz
Block copolymers often create droplets when placed on a substrate. Such nanostructured droplets can be arranged into regular microstructured arrays, thereby forming hierarchically organized materials that can be used in microelectronics, plasmonics, sensing, photonics, metamaterials production, and even cryptography. However, it is unclear if such materials can be stimuli-responsive, i.e., be able to change their nanostructure on a single droplet level upon applying external stimuli. In this work, we discovered that small (10-100 nm) surface-adsorbed droplets of symmetric diblock copolymers can form a multitude of different externally switchable nanostructures. We obtained a near-equilibrium, comprehensive 4D diagram of droplet morphologies by performing large-scale self-consistent field theory (SCFT) calculations under various wetting and phase separation conditions. The SCFT modeling was augmented with a computational algorithm that established an equilibrium droplet morphology in a given system without assuming potentially equilibrium structures prior to simulation. The discovered droplet nanostructures agreed excellently with previously published experimental data. Crucially, we showed that direct and reversible transitions between different droplet morphologies are possible upon changing the interaction strength between components, which can be tuned externally in experiments by adding surfactants or controlling temperature. We confirmed experimental realizability of such stimuli-responsiveness by modeling surfactant addition that led to a switch between droplet nanostructures. This work demonstrates that even the simplest symmetric diblock copolymers are able to produce versatile and stimuli-responsive structures on a surface when confined to a small nanodroplet. This opens the possibility to produce smart coatings with externally switchable hierarchical micro- and nanostructures.
Soft Condensed Matter (cond-mat.soft)
Tailoring Mechanical Properties of Germanium Anodes via Metal Incorporation for Improved Cycle Stability
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-04 20:00 EDT
Koki Nozawa, Noriyuki Saitoh, Noriko Yoshizawa, Takashi Suemasu, Kaoru Toko
Achieving long-term stability in high-capacity lithium-ion battery anodes remains a critical challenge. In this study, we present a materials-intrinsic strategy for extending the cycle life of Ge, a promising next-generation anode material, through trace doping with metal elements. We systematically investigated the effects of small additions of various metals and found that elements with large atomic size, particularly Yb, markedly improved the cycling stability without sacrificing the initial capacity, while appropriate Yb doping enhanced the anode lifetime by approximately a factor of three. Structural and electrochemical analyses revealed that this improvement originates from mechanical softening of the Ge anode, which suppresses lithiation-induced damage such as cracking and delamination. Nanoindentation measurements further showed a strong negative correlation between dopant atomic size and film hardness, establishing anode softening as a new design principle for damage-tolerant electrodes. Although Yb doping reduced the rate capability at high C-rates, the present results demonstrate a clear shift in design strategy from volume-change suppression to mechanical compliance. These findings provide a useful framework for stabilizing high-capacity alloy anodes through atomic-scale mechanical control.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Beyond Structure: Revolutionising Materials Discovery via AI-Driven Synthesis Protocol-Property Relationships
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-04 20:00 EDT
The current structure-centric paradigm in artificial intelligence (AI)-driven materials discovery, despite delivering thousands of candidate structures, is stalling at a critical barrier: the synthesizability gap. We argue that closing this gap demands a pivot to a synthesis-first paradigm in which executable synthesis protocols, not just atomic configurations, are treated as primary design variables. We outline a roadmap built on three pillars: (i) representing synthesis procedures as machine-readable protocols, (ii) deploying generative and inverse-design models to propose actionable reaction pathways and recipes, and (iii) integrating closed-loop optimisation to refine protocols against experimental realities and sustainability constraints. Framed in terms of the causal backbone P->X->y from protocol P to structure X and properties y, this perspective sets out methodological building blocks, standards needs and self-driving laboratory (SDL) integration strategies to accelerate reproducible, data-first materials discovery.
Materials Science (cond-mat.mtrl-sci), Artificial Intelligence (cs.AI)
20 pages, 2 figures
Polarization-controlled effective Rabi dynamics in driven Graphene: A Floquet-Magnus approach
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-05-04 20:00 EDT
V. G. Ibarra-Sierra, J. L. Cardoso, C. Flores-Valente, A. Kunold, J. C. Sandoval-Santana
Polarization ellipticity $ \beta$ and the relative angle $ \Delta$ between electron momentum and driving field act as independent control parameters for coherent dynamics in periodically driven Dirac systems. In this work, we analyze the dynamics of resonantly driven Dirac electrons in graphene under elliptically polarized electromagnetic radiation using the Floquet-Magnus expansion. Working in the interaction picture and applying a rotating-wave-type transformation, we derive an effective two-level Hamiltonian that governs the macromotion at resonance ($ \omega = \Omega/2$ ). The resulting quasienergy splitting depends nontrivially on $ \beta$ and $ \Delta$ through interference between the Bessel harmonics $ J_0(\zeta)$ and $ J_2(\zeta)$ . Circular polarization ($ \beta = \pm 1$ ) restores rotational symmetry and yields a $ \Delta$ -independent effective Rabi frequency, whereas elliptical and linear polarizations produce anisotropic responses with a $ \pi$ -periodic angular modulation. Beyond spectral properties, we identify a polarization-induced phase that acts as an effective initial Floquet kick, shifting the effective initial conditions and producing measurable shifts in the timing of occupation oscillations, whose sign depends on both helicity and relative orientation. Through an explicit Fourier decomposition of the time-evolution operator, we separate macromotion from micromotion contributions and validate the zeroth-order Magnus approximation via numerical simulations, achieving root-mean-square errors of $ \sim 1%$ over 100 driving periods in the weak-field regime. These results establish polarization ellipticity and relative orientation as tunable and experimentally accessible knobs for quantum control in two-dimensional Dirac materials, with direct implications for time-resolved spectroscopy.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
18 pages, 3 figures
Investigation of nonlocal transport associated with the orbital Hall effect in Ti
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-05-04 20:00 EDT
Keitaro Takashina, Naoki Yano, Asahi Oe, Mari Taniguchi, Shuto Kimura, Kazuya Ando
We investigate nonlocal transport in single-layer Ti Hall bars to explore signatures of orbital-current transport driven by the orbital Hall effect. Despite the negligible spin Hall effect in Ti, we observe a finite nonlocal resistance in the single-layer Ti Hall bar and study its dependence on the central channel width. Finite-element simulations show that the measured signal contains a sizable Ohmic bypass contribution. However, the bypass contribution is strongly suppressed at small channel widths and cannot fully account for the observed nonlocal resistance even when variations in the Ti resistivity are taken into account. Our results therefore suggest an additional nonlocal contribution distinct from the Ohmic bypass background, which may be associated with orbital transport driven by the orbital Hall effect in Ti.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Machine learning evaluation of structural descriptors for supercooled water
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-05-04 20:00 EDT
Kohei Yoshikawa, Kokoro Shikata, Kang Kim, Nobuyuki Matubayasi
The anomalous behavior of liquid water is widely associated with a liquid-liquid phase transition between high- and low-density states in the supercooled regime. At the microscopic level, tetrahedral hydrogen-bond networks govern these properties, motivating structural descriptors that characterize local molecular environments. These structural descriptors quantify features such as tetrahedral order, local density, and the separation between the first and second coordination shells; however, they have largely been proposed independently, with limited systematic comparison. Here we evaluate 16 previously proposed descriptors using a neural-network-based temperature classification framework, enabling an objective assessment of their ability to distinguish temperature-dependent structural changes in supercooled water. We further apply an explainable artificial intelligence method that identifies the structural features responsible for the model predictions. This approach reveals how different descriptors encode local structural information and establishes a data-driven framework for benchmarking structural descriptors in liquid water.
Soft Condensed Matter (cond-mat.soft), Chemical Physics (physics.chem-ph)
13 pages, 5 figures, 1table for main text, 10 figures for supplementary information
Kinetically Arrested Twin-Domain State in Formamidinium Lead Iodide
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-04 20:00 EDT
Xia Liang, Milos Dubajic, Zezhu Zeng, Yang Lu, Johan Klarbring, Samuel D. Stranks, Aron Walsh
Hybrid lead halide perovskites exhibit a delicate interplay between average crystallographic symmetry, local structural disorder and A-site orientational dynamics, giving rise to unusual vibrational and electronic behaviour. Here, we combine large-scale molecular dynamics with a density-functional-theory-accurate machine learning force field to resolve the structural dynamics of perovskites across mesoscopic length scales. In formamidinium lead iodide FAPbI$ _{3}$ , we identify a high-temperature $ \alpha$ phase with dynamic local order and correlated tilt nanodomains, an ordered $ \gamma$ phase with long-range $ a^{+}a^{+}a^{+}$ tilt coherence, and, below $ \sim$ 100~K, a history-dependent $ \gamma’$ state consisting of locally $ \gamma$ -like nanoscale regions separated by sharp twin-like boundaries. This low-temperature disordered state is not a distinct bulk polymorph, but a kinetically arrested metastable twin-domain network selected by the interplay between shallow tilt energetics and slowing FA reorientation. This picture provides a consistent explanation for the low-temperature diffuse scattering features observed experimentally, and accounts for the broadened low-energy vibrational response found in the simulations. Furthermore, this unique structural landscape imprints a spatially varying electronic disorder that directly impacts macroscopic optoelectronic properties, evidenced by an anomalous increase in the Urbach energy at low temperatures. Our results reconcile the debated low-temperature behaviour of FAPbI$ _{3}$ in terms of competition between ordered and arrested structural states, and show more broadly that in hybrid perovskites the organic cation can actively select the macroscopic structural and electronic response through its reorientation kinetics, placing thermal history on equal footing with composition as a determinant of structural and optoelectronic properties.
Materials Science (cond-mat.mtrl-sci)
Thermodynamic Charge Partition in Accumulation-Layer Heterostructures
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-05-04 20:00 EDT
We develop a thermodynamic description of accumulation-layer heterostructures in which the induced sheet density is partitioned between the near-interface accumulation-layer charge and a complementary screening charge in the surrounding structure. Treating this partition as the central state variable yields a complete Helmholtz free energy, a corrected locked-branch chemical potential, and a shifted release potential that separates energetic path selection from geometric capacitance. The physical path is selected spectrally: compressible segments remain fully screened, whereas incompressible segments evolve along a locked branch until release is triggered by the relevant gap. Differential capacitance, tunnel current and plateau width then emerge as different projections of the same coupled thermodynamic structure. A canonical two-stage self-consistent Poisson–Schrödinger reduction supplies universal master functions for the isolated accumulation layer and master surfaces for its finite-buffer extension, making the theory calculable across density and geometry. Comparison with magnetocapacitance and magnetotunneling data supports a picture in which nearby extended charge refills the accumulation layer and the effective screening depth grows with magnetic field.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
26 pages, 14 figures
An Advanced Epitaxial Strategy Enabling Vertical GaN Devices on Silicon Wafers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-04 20:00 EDT
Fumio Kawamura, Takeyoshi Onuma, Kazutaka Mitsuishi
While vertical GaN-on-silicon architectures promise a transformative leap in cost-effective power electronics and high-resolution micro-LEDs, their deployment remains bottlenecked by the high electrical resistance of conventional epitaxial buffer layers. Here, a universal and straightforward sputtering-based strategy is presented to realize high quality GaN epitaxial films on Si(111) substrates characterized by exceptionally low vertical resistance, ohmic behavior, and robust thermal stability. This technique centers on the in-situ formation of a sub nanometer (0.5 nm) silicide-based template via rapid thermal annealing method demonstrating unprecedented versatility across 25 different metallic species. Scanning transmission electron microscopy (STEM) reveals that a unique amorphous like interlayer (AL-IL) effectively accommodates lattice mismatch and relaxes epitaxial strain. These AL-IL templates further serve as high performance platforms for metalorganic chemical vapor deposition (MOCVD) overgrowth, successfully bridging the gap between scalable, low-cost fabrication and device-grade vertical performance.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
19 pages, 6 figures
Signatures of time-reversal-symmetry breaking in multiband 2H-TaS2 revealed by zero-field Josephson nonreciprocity
New Submission | Superconductivity (cond-mat.supr-con) | 2026-05-04 20:00 EDT
Daniel Margineda, David Caldevilla-Asenjo, Yuriy Yerin, Covadonga Álvarez-García, Andrei Mazanik, Maxim Ilyn, Celia Rogero, Luis E. Hueso, F. Sebastian Bergeret, Marco Gobbi
Superconductors that spontaneously break time-reversal symmetry host complex order parameters and are widely regarded as a hallmark of unconventional superconductivity. Whether such symmetry breaking can also arise in superconductors with nominally isotropic spin-singlet pairing remains an open question. Here we report a zero-field Josephson diode effect in noncentrosymmetric 2H-TaS2/2H-NbSe2 van der Waals junctions. The diode efficiency shows no systematic correlation with supercurrent amplitude, TaS2 thickness, or normal-state resistance, arguing against simple extrinsic, purely interfacial, or transparency-driven mechanisms. Time-reversal-symmetric scenarios are further tested using symmetry-controlled and molecule-intercalated control devices, in which the nonreciprocal response is absent or strongly reduced. Normal-state Hall transport in TaS2 exhibits a nonlinear response consistent with multiband correlated electronic states. Within a Josephson framework, our modelling shows that interband scattering acts as a phase-locking mechanism generating an intrinsic anomalous phase difference and a nonsinusoidal asymmetric current-phase relation, leading to finite zero-field rectification. Together, zero-field Josephson nonreciprocity and nonlinear Hall transport provide complementary evidence for a multiband superconducting phase structure in 2H-TaS2, consistent with intrinsic time-reversal-symmetry breaking.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
Pre-charging polymer surfaces enhances droplet mobility and electrification
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-05-04 20:00 EDT
Shuaijia Chen, Kenta Morita, Dumindu Dassanayaka, Hans-Jürgen Butt, Peter C. Sherrell, Amanda V. Ellis, Joseph D. Berry
Surface-bound electric charge on polymer materials can strongly influence droplet behaviour and solid-liquid charge transfer, but the mechanisms and the means to control these effects remain unclear. In this work, we systematically controlled the surface charge on polymer surfaces, including polytetrafluoroethylene (PTFE) and Nylon-66, by first neutralising the surfaces with an anti-static ion blower and then applying charge using an ion gun. We find that droplets pick up pre-deposited surface ions during the first wetting of the surface, and that the transferred charge directly correlates with the deposited charge encountered by the wetted area for moderate deposited densities (|{\sigma}_d |<40 {\mu}C/m2) independent of material properties. We also demonstrate that the deposited charge reduces contact angle and increases contact-line mobility in a manner consistent with an increase in effective solid surface energy. For higher surface charge densities, we observe instabilities such as droplet splitting or detachment. This work demonstrates an effective approach to control solid-liquid electrification, enabling amplification or suppression of surface charge and the directed manipulation of fluid motion on surfaces.
Soft Condensed Matter (cond-mat.soft), Fluid Dynamics (physics.flu-dyn)
Electrical detection of spin-flip transition in metal/Na5Co15.5Te6O36 heterostructure
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-05-04 20:00 EDT
Hirotsugu Tagami, Takuya Kawada, Yuki Shiomi
We report on the longitudinal magnetoresistance (MR) in thin metal films on an Ising-type antiferromagnetic insulator, Na5Co15.5Te6O36 (NCTO). Steep changes in the MR spectra with hysteresis were observed at spin-flip transitions driven by magnetic fields applied along the easy axis of the NCTO crystal. The MR jumps almost follow step-like changes in magnetization at the spin-flip transition. At very low temperatures where Co moments are partially frozen, the MR anomalies exhibit a tunnel-magnetoresistance-like shape. The observed MR anomalies at the spin-flip transition are attributed to strain effects via magnetostriction upon the magnetic-structure change of the Co nets in NCTO, because similar MR jumps are observed in both Pt/NCTO and Cu/NCTO. Interestingly, we found that the high-field slopes of the MR spectra show opposite signs between Pt/NCTO and Cu/NCTO at low temperatures. Because the opposite signs of the high-field MR are prominent below the antiferromagnetic transition temperature of NCTO, the interaction between the interface spin accumulation and magnetization is likely to contribute to the MR effect in the induced ferromagnetic state.
Strongly Correlated Electrons (cond-mat.str-el)
7 pages, 4 figures
Induced discommensurations in the lock-in transition of charge-density waves
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-05-04 20:00 EDT
Katsuhiko Inagaki, Satoshi Tanda
We studied McMillan’s free energy of the lock-in transition in charge-density waves. The wave profiles near the critical value were obtained by numerical annealing. First, we demonstrated that our method reproduces the previous studies. The obtained wave profiles include discommensurations near the critical value. Then, we calculated possible wave profiles in the commensurate state. We found that discommensurations are able to be excited in the commensurate state, leading the system to turn out to an incommensurate state. We proposed that these wave profiles result from topological invariants. Moreover, excitation of the discommensurations is favorable for the direction to the original wavelength of the incommensurate state. This is attributed to the nature of McMillan’s free energy. The current-induced incommensurations, which we discovered with the diffraction study of $ o$ -TaS$ _3$ [Inagaki \textit{et al.}, J. Phys. Soc. Jpn. 77, 093708 (2008)], is consistent with this study.
Strongly Correlated Electrons (cond-mat.str-el)
10 pages, 4 figures
Magnetic Behavior of Ferro-, Antiferro-, and Ferrimagnetic Systems in the Griffiths Phase: A Theoretical Study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-04 20:00 EDT
In this report, we provide a theoretical framework for the magnetic behavior of the Griffiths phase, which, along with three-dimensional spin-1/2 Ising ferromagnetic systems, can be extended to antiferromagnetic as well as ferrimagnetic systems. We find that the magnetic behavior in the Griffiths phase of three-dimensional antiferromagnetic and ferrimagnetic systems is more unusual than that of conventional ferromagnetic systems. However, this study offers a possible framework for the identification of Griffiths phase behavior in three-dimensional antiferromagnetic and ferrimagnetic systems.
Materials Science (cond-mat.mtrl-sci)
5 Figures
Incommensurate Magnetic Ordered Phase with Enhanced Low-Temperature Magnetic Specific Heat in SmAu$_3$Al$_7$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-05-04 20:00 EDT
Ryuji Higashinaka, Takuma Iwami, Kohsuke Saitou, Takashi U. Ito, Chihiro Tabata, Koji Kaneko, Takashi Ohhara, Ryoji Kiyanagi, Akiko Nakao, Jumpei G. Nakamura, Wataru Higemoto, Akihiro Koda, Shinsaku Kambe, Yuji Aoki, Tatsuma D. Matsuda
Neutron scattering and muon spin rotation ($ \mu$ SR) measurements on single-crystal SmAu$ 3$ Al$ 7$ reveal magnetically ordered states associated with successive transitions at $ T{\rm N}$ = 2.8 K and $ T^\ast$ = 0.9 K. Magnetic Bragg peaks appear below $ T{\rm N}$ with an incommensurate (IC) propagation vector $ {\bf q}$ = (0.30, 0, 1.33). $ \mu$ SR detects spontaneous internal fields below $ T_{\rm N}$ , and the spectral shape is consistent with the IC magnetic ordering. No anomalies are observed at $ T^\ast$ , indicating that the magnetic structure remains essentially unchanged below and above $ T^\ast$ . The magnetic order is revealed to be a spatially homogeneous long-range ordered state, rather than a partially disordered state proposed in earlier studies. The possible connection between the IC magnetic order and the enhanced low-temperature magnetic specific heat is discussed.
Strongly Correlated Electrons (cond-mat.str-el)
13 pages, 5 figures
J. Phys. Soc. Jpn., Vol.95, No.6, Article ID: 063702 (2026)
Parity-dependent reentrant topology in a Su–Schrieffer–Heeger chain with power-law quasiperiodic modulation
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-05-04 20:00 EDT
Yusheng Niu, Hui Liu, Zhihao Xu
We investigate reentrant topological transitions in a one-dimensional Su–Schrieffer–Heeger chain with power-law quasiperiodically modulated intracell hopping. The modulation is characterized by a positive integer exponent $ n$ and a tunable parameter $ \beta$ , which continuously interpolates between the smooth power-law quasiperiodic limit and a sign-function limit that becomes square-wave-like for odd $ n$ and uniform for even $ n$ . By combining analytical calculations of the zero-mode inverse localization length with numerical evaluations of a real-space topological indicator, we determine the topological phase diagrams in the $ \beta\to 0$ , $ \beta\to\infty$ , and finite-$ \beta$ regimes. We show that deterministic quasiperiodic modulation can induce TAI-like reentrant topological phases within finite parameter windows. The formation of these phases depends crucially on the parity of $ n$ : for positive modulation strength, odd-power modulations can induce reentrant topology from the clean trivial regime $ |t_1|>1$ , whereas even-power modulations allow such reentrance only from the negative clean trivial regime $ t_1<-1$ . Exact analytical expressions for the zero-mode inverse localization length are obtained for $ n=1,2,3,4$ , yielding explicit or implicit transition conditions. The finite-$ \beta$ results demonstrate that the parity-dependent structure remains robust throughout the interpolation between the two limiting cases. This parity effect originates from whether the modulation preserves or removes the sign structure of $ \cos x$ . We further propose an electrical-circuit implementation and discuss experimentally accessible signatures of the reentrant trivial–topological–trivial transition.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
29 pages, 6 figures
An Unsupervised Machine Learning-based Framework for Wafer Scale Variability Analysis and Performance Prediction of Ferroelectric Hf0.5Zr0.5O2 Thin Film Capacitors
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-04 20:00 EDT
Fabrication process-induced performance variability remains a formidable barrier in the high-volume manufacturing of semiconductor chips. With skyrocketing Artificial Intelligence (AI) workload, demand for non-volatile and computational memories is growing exponentially. As embedded non-volatile memory, ferroelectric Hf0.5Zr0.5O2 emerged as a strong candidate due to their CMOS back-end-of-line (BEOL) compatibility, scalability and high performance. However, their sensitive crystallization kinetics leads to significant device-to-device (D2D) non-uniformity leading to unpredictability of performance over wafer scale. In this work, we demonstrate unsupervised machine learning can analyze intra-die D2D variations and predict performance of “unseen” dies efficiently. We present a framework utilizing Principal Component Analysis (PCA) and K-Means clustering to analyze D2D performance variations in HZO capacitors and building on data from multiple dies, we move beyond traditional descriptive statistics to a predictive “Virtual Metrology” approach that separates performance categories, defined by key parameters like remanent polarization (Pr) and coercive voltage (Vc). The analysis further extends to comparing uniformity across different dies across the wafer showing the proposed methodology can accurately predict device performance on untested dies with a low Mean Absolute Percentage Error (MAPE) in the range of 5-10%, suggesting a robust path for accelerated yield improvement and reduced metrology overhead.
Materials Science (cond-mat.mtrl-sci)
Exact Analytical Vortex Solution for a Two-Dimensional Quantum Gas with LHY Correction
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-05-04 20:00 EDT
Ibrar, Mahammad Ahmed Hussain, Ayan Khan
In this investigation, we provide an exact analytical vortex solution for a Bose liquid in two dimensions with beyond mean-field correction (BMF). Analytical solutions in two-dimensional systems with BMF corrections are rarely found in the literature. The present result provides a clear framework for understanding vortex structures in low-dimensional quantum fluids and serves as a reliable benchmark for future theoretical and experimental studies.
Quantum Gases (cond-mat.quant-gas)
6 Pages, 7 Figures
Fixed points and crossovers for the hysteresis scaling of dynamic mean-field models
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-05-04 20:00 EDT
Phase transitions are divided into first-order phase transitions and continuous ones in current classification. While the latter shows striking phenomena of scaling and universality, the former is generically characterized by discontinuous jumps in extensive variables and pronounced hysteresis. Recent studies have demonstrated universal scaling behavior controlled by a cubic fixed point in first-order phase transitions. However, more recent investigations into the hysteresis in a dynamic mean-field quartic model driven through its first-order phase transitions have revealed new scaling exponents for different driving rates. Here, we discover a new exponent for large driving rates arising surprisingly from critical phenomena and show that, depending on the magnitude of the driving rates and on the absence or presence of noise, the same mean-field model remarkably exhibits several universality classes with definite universal scaling exponents governed by their corresponding fixed points through a systematic scaling analysis based on renormalization group theory. The theories and their various crossovers between different fixed points along with complete universal scaling of full curve collapse are verified by numerical results. This further confirms universal scaling in first-order phase transitions.
Statistical Mechanics (cond-mat.stat-mech)
9 pages, 2 figures
Dynamical magnetotropic susceptibility as a new probe of Kitaev materials and beyond
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-05-04 20:00 EDT
João C. Inácio, J. Schwab, G. Rakhmanova, S. Safari, V. Zambra, H. Nasir, S. Paschen, K. A. Modic, Fakher F. Assaad, Toshihiro Sato
The magnetotropic susceptibility $ k(\omega)$ probes ultra-low-frequency uniform fluctuations. For a crystal mounted on an oscillating cantilever in a magnetic field, it is defined as the ratio of torque to angular-displacement amplitude. Its real and imaginary parts determine the oscillation-frequency shift and crystal-induced damping. It is a low-energy probe of uniform $ q=0$ spin and charge degrees of freedom. We demonstrate this by deriving $ k(\omega)$ within linear response theory for a generic correlated-electron Hamiltonian with charge and spin degrees of freedom. Although it covers metallic and insulating magnets, correlated paramagnets, and exotic quantum critical points, we focus on limiting cases. For insulating spin systems $ k(0)$ is sensitive to magnetic anisotropy whereas its finite-frequency imaginary part probes uniform dynamical spin susceptibility even in spin-symmetric models. For metallic systems we identify when eddy currents cause low-frequency damping. Our numerical results focus on Kitaev-material magnetotropic response. Using auxiliary-field quantum Monte Carlo with machine-learning-based sign-problem optimization we compute $ k(\omega)$ for several models proposed for $ \alpha$ -RuCl$ _3$ . The observed low-temperature scaling of $ k(0)/T$ with $ B/T$ results from dominant Kitaev couplings: parameter sets without dominant Kitaev coupling do not exhibit this scaling. It remains robust upon inclusion of optical phonons. Beyond the static response, $ k’’(\omega)$ for the $ \alpha$ -RuCl$ _3$ parameter set reproducing the experimental $ k(0)$ data shows local-moment features at high and low $ T$ , with a single peak at the Larmor frequency. Beyond Kitaev systems we highlight broader applications. Probing ultra-low-energy uniform charge fluctuations is pertinent to Kondo destruction quantum criticality, of broad interest in strange metallicity and unconventional superconductivity.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
35 pages, 8 figures
Quantum corrections to the Josephson dynamics: a population-imbalance approach
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-05-04 20:00 EDT
Oliver Hideg, Sofia Salvatore, Luca Salasnich
We investigate quantum corrections to the Josephson dynamics of two weakly coupled Bose-Einstein condensates using the population imbalance as the sole dynamical variable. Starting from the two-variable action, we derive the imbalance-only Lagrangian with a position-dependent mass and quantize it via symmetric operator ordering. The leading quantum corrections to the classical potential and mass are computed via the one-loop quantum effective action, using a covariant background-field method that fully accounts for the coordinate dependence of the mass. This yields explicit expressions for the effective potential and the effective mass, from which we derive the quantum-corrected Josephson frequency. Numerical comparison with exact diagonalization of the two-site Bose-Hubbard model shows that the imbalance-only formulation outperforms the complementary phase-only approach in the regime of strong interactions, which is the natural domain of validity of the population-imbalance description.
Quantum Gases (cond-mat.quant-gas), Superconductivity (cond-mat.supr-con)
7 pages, 3 figures
Long range proximity effects in planar structures involving the halfmetal ferromagnet La0.7Sr0.3MnO3 and Pt interlayers
New Submission | Superconductivity (cond-mat.supr-con) | 2026-05-04 20:00 EDT
Junxiang Yao, Julian van Doorn, Mariona Cabero, Jan Aarts
Over the last decade, there has been steady research on superconducting junctions with a ferromagnet as the weak link, and where triplet correlations can transport supercurrents over a substantial distances. Of particular interest are halfmetallic ferromagnets, in which only one spin band is present, so that, presumably, the induced supercurrent is fully spin-polarized. We have earlier reported on a study of triplet transport in planar La0.7Sr0.3MnO3(LSMO) nanostrip Josephson junctions with NbTi superconducting contacts, where we found high values for the supercurrents, and large junction lengths (up to 1.3 {\mu}m). Here, we extend that work by studying the dependence of the critical current Ic on the length of the nanostrip between the contacts and the width of the strip. All junctions show strong supercurrents, but we do not observe simple systematics. Apparently, the fabrication process does not allow sufficient control over some of its parameters. To gain more insight in the mechanism for triplet generation at the LSMO/NbTi interface, we also studied the effect of Pt as an interlayer between the LSMO and the NbTi. For this, we etched a NbTi/Pt electrode structure on a full film of LSMO. The results are highly promising, showing sharp superconducting transitions and zero-resistance states being reached at an electrode distance of 2 {\mu}m, with indications that larger distances should be feasible.
Superconductivity (cond-mat.supr-con)
8 pages, 6 figures
Atomic Interferometry with Spin-Orbit-Coupled Spin-1 Condensates
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-05-04 20:00 EDT
Renfei Zheng, Junying Wu, Josep Cabedo, Alessio Celi, Zhihao Lan, Weiping Zhang, Lu Zhou
We propose and analyze a quantum interferometry scheme based on a Raman-dressed Bose gas with spin-orbit coupling. In this system, the atom-light coupling mixes spin and momentum degrees of freedom, giving rise, in the low-energy regime, to an effective spinor condensate whose spin-mixing interaction can be tuned independently of the atomic density. This controllability enables a separation between state preparation and phase imprinting, and provides a natural route to echo-type protocols based on effective time reversal. Within this framework, critical regimes of the effective spinor Hamiltonian can be used to generate entanglement and enhance interferometric sensitivity beyond the standard quantum limit. In addition, the spin-momentum locking of the dressed modes gives access to spatial density modulations that provide an alternative readout of the interferometric phase. In particular, phase information can be extracted from the displacement of spin-orbit-induced density stripes even when conventional spin observables are insensitive within the effective spinor description. Our results identify Raman-dressed spinor gases as a flexible platform for nonlinear atomic interferometry, combining controllable spin-mixing dynamics with spatially resolved phase readout.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
comments are welcome
Coordination-Induced Tuning of Ligand-Centered Red Emission in a cis-[Cd(Tz)2(py)2] Complex for Light-Emitting Diodes
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-04 20:00 EDT
Samara M. da Silva, R. F. Silva, A. Nonato, Paulo Villis, Rodrigo S. Corrêa, L. C. Gómez-Aguirre, C.W.A. Paschoal, Pedro I. S. Maia, Benedicto A. V. Lima
Organic–inorganic complexes are promising materials for light-emitting applications. Here, we report a new organometallic complex, cis-[Cd(Tz)$ _2$ (py)$ _2$ ], featuring a distorted octahedral Cd(II) coordination environment. IR and Raman spectroscopy reveal pronounced coordination-induced changes, particularly in the Raman response of the triazene moiety, indicating electronic and structural perturbation upon Cd(II) complexation. Hirshfeld surface analysis shows that the crystal packing is mainly governed by H$ \cdots$ H, O$ \cdots$ H/H$ \cdots$ O, and C$ \cdots$ H/H$ \cdots$ C contacts, whereas $ \pi$ –$ \pi$ stacking interactions contribute modestly. Solid-state UV–Vis spectroscopy reveals broad absorption from $ \sim$ 700 to 200 nm and a direct optical band gap of 1.83 eV, indicating semiconductor-like behavior. Photoluminescence measurements show a broad emission band at 500–850 nm with enhanced red contribution upon coordination. The emission is mainly assigned to ligand-centered transitions ($ \pi \rightarrow \pi^\ast$ and $ n \rightarrow \pi^\ast$ ), consistent with the $ d^{10}$ configuration of Cd(II), which suppresses metal-centered and charge-transfer processes. The CIE chromaticity coordinates confirm warm emission, highlighting the potential of cis-[Cd(Tz)$ _2$ (py)$ _2$ ] for red-emitting optoelectronic applications.
Materials Science (cond-mat.mtrl-sci)
Superconducting diode effect in correlated electron systems by nonreciprocal magnetism
New Submission | Superconductivity (cond-mat.supr-con) | 2026-05-04 20:00 EDT
Kyohei Nakamura, Youichi Yanase
The superconducting diode effect (SDE), characterized by a nonreciprocal critical current in superconductors, has recently been observed in strongly correlated electron systems and near quantum criticality, pointing to unconventional mechanisms beyond weak-coupling theories. Here we investigate the SDE in the Rashba-Zeeman-Hubbard model, which captures $ d$ -wave superconductivity in an antiferromagnetic quantum critical regime, using the Dyson-Gor’kov equation with the fluctuation exchange approximation. We show that electron correlations suppress the conventional intrinsic SDE arising from depairing currents. More importantly, a supercurrent nonreciprocally induces antiferromagnetic order, which fundamentally governs the critical current and enables perfect diode efficiency. Our results reveal a previously unrecognized correlation-driven mechanism of the SDE and establish strongly correlated superconductors as a platform for superconducting diode physics.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
Coordination Engineering of Dual-Atom Catalysts for Overall Water Splitting: Mechanistic Insights from Constant-Potential First-Principles and Machine Learning
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-04 20:00 EDT
Jiahang Li, Suhang Li, Chong Yan, Jiajun Yu, Qinzhuang Liu, Ruo-Ya Wang, Dongwei Ma
The rational design of bifunctional electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is essential for achieving efficient and cost-effective overall water splitting. Atomically dispersed transition-metal catalysts, including single-atom catalysts and dual-atom catalysts (DACs), have emerged as a prominent class of heterogeneous catalysts, in which coordination engineering plays a decisive role in tuning catalytic performance. Herein, we explore coordination-engineered bifunctional overall water splitting electrocatalysts using graphene-supported DACs (TM1TM2-C6-xNx) as model systems. By tuning C/N coordination and dual-metal combinations (Fe, Co, Ni, and Cu), a library of 228 structures was constructed. A three-step screening strategy, combining constant-charge and constant-potential density functional theory with kinetic analysis of proton-coupled electron transfer (PCET), identifies 24 highly active candidates (TM1TM2 = CoNi, CoCu and Co2) with mixed C/N coordination for OER. These catalysts exhibit overpotentials comparable to that of IrO2 and low PCET barriers (lower than 0.40 eV), among which 22 also show high HER activity. Machine learning reveals clear coordination-dependent structure-performance relationships. Such bifunctionality arises from coordination engineering that enables the simultaneous optimization of OER intermediate adsorption and the hydrogen binding strength for HER. This work establishes coordination engineering as an effective strategy for designing high-performance bifunctional dual-atom electrocatalysts for overall water splitting.
Materials Science (cond-mat.mtrl-sci)
Suppressing spin qubit decoherence during shuttling via confinement modulation
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-05-04 20:00 EDT
Daniel Q. L. Nguyen, Maximilian Rimbach-Russ, Stefano Bosco
Reliable long-range qubit shuttling is a powerful tool for scalable quantum computing architectures. We investigate strategies to improve the coherence of moving spin qubits by performing continuous dynamical decoupling by modulating their confinement potential. Specifically, we introduce temporal and spatial breathing shuttling protocols that leverage spin-orbit interactions in hole-spin systems to electrically drive the qubit while moving. This enables efficient dressed-state shuttling, where the spin is continuously rotated during transport, suppressing the effect of low-frequency noise. Using the filter function formalism, we identify driving regimes that efficiently mitigate both global and local magnetic and electric noise sources. We find that confinement-modulated shuttling can significantly enhance coherence during transport, while revealing distinct limitations depending on the correlation length of the noise. Applying our framework to germanium hole-spin qubits, we show that these protocols provide a practical route toward noise-resilient long-range coherent quantum links.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
main 13 pages, 6 figures, 1 table appendix 5 pages
Monte Carlo study of the superfluid phase of $^4$He
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-05-04 20:00 EDT
Detailed numerical results obtained with state-of-the-art Quantum Monte Carlo (QMC) simulations are presented for the superfluid phase of $ ^4$ He at saturated vapor pressure. The aim of this contribution is that of providing reliable, up-to-date estimates for this archetypal superfluid, reflecting the methodological progress that has taken place over the past two decades. We simulate a system comprising 2,048 helium atoms, i.e., an order of magnitude greater in size than those for which results currently regarded as standard references were originally obtained. We offer revised estimates for energetic and structural properties, as well as for the ground state condensate fraction.
Statistical Mechanics (cond-mat.stat-mech)
To appear in J. Phys. Conference Series as part of the Proceedings of the Phenikaa International Physics Conference held in Hanoi, October 2025
Born-Qualified: An Autonomous Framework for Deploying Advanced Energy and Electronic Materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-04 20:00 EDT
Steven R. Spurgeon, Milad Abolhasani, Frederick Baddour, Ryan B. Comes, Vinayak P. Dravid, Hilary Egan, Patrick Emami, Robert W. Epps, Davi M. Fébba, Renae Gannon, E. Ashley Gaulding, Ayana Ghosh, Kenny Gruchalla, Grace Guinan, Taro Hitosugi, Michael Holden, Sergei V. Kalinin, Yangang Liang, John S. Mangum, Matthew J. Olszta, Nathaniel H. Park, Axel Palmstrom, Michelle A. Smeaton, Brooks Tellekamp, Nicholas E. Thornburg, Raymond R. Unocic, Daniela Ushizima, Rama K. Vasudevan, Robert White, Andrew Young, Andriy Zakutayev
Autonomous science is transforming how we discover materials and chemical systems for advanced energy technologies. However, many initially promising systems never reach deployment. This “valley of death” stems from optimization that prioritizes laboratory metrics over industrial viability. We propose a new strategy: “born-qualified” autonomous development, which embeds manufacturability, cost, and durability constraints from the outset. This approach is enabled by four pillars, including the development of multi-objective metrics, causal models, a modular infrastructure, and embedding manufacturing in the discovery loop. Realizing this vision will require sustained, community-wide commitment, but the potential return on that investment is commensurate with the scale of the challenge.
Materials Science (cond-mat.mtrl-sci), Artificial Intelligence (cs.AI)
14 pages, 2 figures
Dispersion of multiple charged species in an axially symmetric slowly varying channel
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-05-04 20:00 EDT
Thakurdas Mahata, Anirban Chatterjee, Ameeya Kumar Nayak
The transport and dispersion of multiple species of charged ions are central to many biological and physical processes, including electrokinetic ion separation. However, most theoretical studies of dispersion in channels have focused on neutral solutes, leaving the transport of multiple charged species comparatively unexplored. Differences in ionic diffusivities in a multispecies electrolyte solution generate an self-induced electric fields that drive electromigration. To capture these effects at the macroscopic scale, we combine the lubrication approximation with homogenization theory, under electroneutrality and zero-current constraints, to derive an effective transport equation governing the cross-sectionally averaged concentrations. We apply our model framework to a range of channel geometries and compute the resulting effective dispersion coefficients. Finally, we investigate how channel geometry can be tuned to enhance ionic separation. We observe a geometry-induced electro-diffusive coupling that inhibits solute dispersion in certain channels, leading to a non-monotonic Number of Theoretical Plates (NTP) and making such channels ideal for separation processes.
Soft Condensed Matter (cond-mat.soft)
Renormalized entropy production for optimal transport in jump processes: Make conservative forces optimal again
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-05-04 20:00 EDT
Andreas Dechant, Jann van der Meer
For continuous-space diffusion processes, there is a strong connection between conservative forces and entropy production. For a given time evolution of the system’s state, the entropy production is minimized when the system is driven by a unique conservative force. However, this relation does not extend to jump processes on a discrete state space. In this case, the forces that minimize the entropy production are generally nonconservative, this effect is more pronounced far from equilibrium in the presence of high energy barriers. Here we show that, while conservative forces do not minimize the entropy production for a given time evolution, they are nevertheless uniquely characterized as the minimizer of a quantity we dub the renormalized entropy production. This work explores the properties this quantity shares with entropy production as well as crucial differences between them. We also discuss the conceptual and physical differences between the corresponding optimization problems in finite time. Our theoretical calculations are illustrated with explicit numerical examples.
Statistical Mechanics (cond-mat.stat-mech)
Architecting mechanosensitive nanofluidic transport in graphite nanoslits
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-05-04 20:00 EDT
Mathieu Lizée, Zhijia Zhang, Baptiste Coquinot, Qian Yang, Lydéric Bocquet
Mechanosensitive ion transport plays a central role in enabling living systems to perceive and adapt to their environment through the deformation of soft, embedded ion channels. In this work, we demonstrate that ion transport within a two-dimensional graphite nanoslit can be rationally engineered to achieve a bipolar, pressure-sensitive response without any structural deformation. The mechanosensitivity arises from the selective charging of one channel inlet, which acts as a reversible source of mobile charge carriers. These excess-ions can then be advected in or out of the channel by the pressure-driven water flow, thereby modulating the ionic conductance. This mechanism is captured through a comprehensive electrohydrodynamic model that analytically accounts for coupled diffusion, convection, surface transport, diffusio-osmosis, and interfacial slippage, both inside and outside the nanoslit. The theoretical framework quantitatively reproduces the experimental data, showing that a simple surface charge pattern can give rise to complex, pressure-dependent conductance. These findings reveal how rich nonlinear couplings at the nanoscale can be harnessed to design adaptive, bioinspired nanofluidic systems, exemplified here by ionic pressure sensors.
Soft Condensed Matter (cond-mat.soft), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
9 pages, 4 figures
Experimental Evidence of Fractional Entropy in Critical Kondo Systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-05-04 20:00 EDT
C. Piquard, A. Veillon, Y. Sato, F. Zanichelli, A. Aassime, A. Cavanna, U. Gennser, A. K. Mitchell, A. Anthore, F. Pierre
Unconventional quantum states defying the ubiquitous Fermi-liquid paradigm can emerge in the presence of strong electronic correlations. Among these, non-Abelian anyons - such as Majorana zero modes and Fibonacci anyons - are of particular interest for topological quantum computing due to their non-integer quantum dimensions d>1, which allows for protected non-local encoding and processing of quantum information. However, despite considerable efforts, the unambiguous characterisation of such anyons via transport measurements has proved challenging. Instead, here we provide experimental evidence for the low-temperature fractional entropy Delta S associated with a single anyon, which directly implies its non-Abelian character through the relation Delta S = kB ln(d). This thermodynamic signature is measured in metal-semiconductor quantum circuits engineered to realize quantum-critical states from frustrated interactions. Using a micrometre-scale metallic island coupled to two or three electronic leads, we tune the system to two-channel and three-channel Kondo critical points. By measuring the island charge and exploiting a thermodynamic Maxwell relation, we estimate the entropy associated with the anyons that emerge in these critical states. Our observations reveal fractional values, exposing non-Abelian anyons. The corresponding scaling dimensions are consistent with theoretical predictions for a Majorana zero mode Delta S = kB ln(sqrt(2)) and a Fibonacci anyon Delta S = kB ln(1 +sqrt(5))/2 for two and three channels. These findings establish entropy measurements as a powerful tool for characterizing exotic quantum states.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
Entropy transport through a superfluid quantum point contact: A Keldysh field-theory approach
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-05-04 20:00 EDT
Davide Bertolusso, C.J. Bolech, Thierry Giamarchi
We study the matter and entropy transport between two ultra-cold neutral Fermi-gas reservoirs linked by a quantum point contact under a chemical-potential gradient. We describe the two leads with a BCS mean-field model and derive the current-bias characteristics for both particle and entropy transport. We compute the out of equilibrium steady-state currents by using the Keldysh formalism. In accordance with previous works in the literature, we confirm the well-known behavior for the particle current and extend the computation to the entropy current in the BCS regime. The entropy current shows an oscillatory behavior at low voltage in the ballistic junction limit. We analyze the results for a wide range of values of the junction’s transparency. We also compare our findings with experimental results in cold atomic gases in the unitary regime.
Quantum Gases (cond-mat.quant-gas), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
TrueEBSD in MTEX: automatic image matching for correlative microscopy applications
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-04 20:00 EDT
Vivian Tong, Stefan Olovsjö, Rachid M’Saoubi, Mathias Grabner, Manuel Petersmann, Liam Wright
TrueEBSD is an open-source MATLAB program for image alignment and spatial distortion correction of images and electron backscatter diffraction (EBSD) maps. We have re-implemented TrueEBSD as an add-on to MTEX, an established toolbox for EBSD data analysis. Spatial alignment enables correlative analysis methods, such as augmenting EBSD orientation maps with data from other imaging modes. The augmented EBSD maps can then be analysed further using MTEX. We demonstrate TrueEBSD on two example case studies: one for measuring Co phase fraction and WC contiguity in a WC-Co composite, and another for determining the relative susceptibility of grain boundaries to void formation in a copper polycrystal. In both examples, the EBSD map was augmented with scanning electron microscopy (SEM) image data. This enabled quantitative crystallographic measurements which would not be possible from analysing the EBSD maps and images separately.
Materials Science (cond-mat.mtrl-sci)
23 pages, 12 figures. Source code at this https URL, copper dataset at this https URL, related example WC-Co dataset at this https URL
Reconstruction of spin structures from topological charge distributions via generative neural network systems
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-05-04 20:00 EDT
Kyra H. M. Klos, Jan Disselhoff, Michael Wand, Karin Everschor-Sitte, Friederike Schmid
Localized topological defects inherently possess a multiscale character. While their microstructure configuration depends on the specific physical system, their topological features and mutual interactions can be described on the macroscale in terms of a particle representation. However, determining the physical properties associated with a given defect pattern often requires knowledge of the underlying microscopic structure. In this work, we extend a Wasserstein generative adversarial neural network by incorporating physical constraints and Fourier-space information to generate microscopic spin configurations consistent with prescribed macroscopic patterns and thermodynamic parameters. Using the two-dimensional XY model as a test case, where vortex-antivortex pairs act as long-range interacting defects, we show that the model generates spin configurations that accurately reproduce magnetization, susceptibility, helicity modulus, and spin-spin correlations over a wide range of temperatures below the Kosterlitz-Thouless transition. At the same time, deviations in the specific heat reveal limitations in reproducing higher order energy fluctuations. A complementary analysis based on topological data analysis uncovers subtle differences in global spin-correlation structures at near critical temperatures that are not apparent from conventional correlation functions alone. These results demonstrate both the promise and current limitations of generative approaches for multiscale studies of defect-dominated spin systems and at the same time highlight topological methods as valuable tools for characterizing critical behavior.
Statistical Mechanics (cond-mat.stat-mech)
Oxygen Vacancies at Dislocation Core Modulate Plasticity in Strontium Titanate
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-04 20:00 EDT
Min-Chul Kang, Chunxu Yan, Alexander Frisch, Xufei Fang, Liming Xiong, Lin Zhou
Dislocation core chemistry in oxides critically influences mechanical behavior and functionality; yet the evolution of core chemistry during the dislocation motion in them has not been directly observed. Here, using SrTiO3 as a model material, we combine aberration-corrected scanning transmission electron microscopy and electron energy-loss spectroscopy with atomic-level molecular dynamics (MD) simulations to correlate the <110>{1-10} dislocation core structure, oxygen vacancy density, charge state, and mobility with each other. We find that the mechanically induced dislocation loops exhibit dissociated cores, whose oxygen vacancy density depends on the gliding distance: short loops are Ti-reduced and oxygen-deficient at the edge dislocation core, whereas longer loops remain close to stoichiometry in both the edge and screw components. MD simulations reveal that kink-assisted edge dislocation glide in SrTiO3 leaves oxygen-deficient trails behind, modulating the oxygen content inside the edge core. These results demonstrate that oxygen-vacancy evolution at the dislocation core intrinsically couples with plasticity in ionic crystals, suggesting a mechanism for oxygen vacancy-dependent dislocation mobility in plastically deformed oxides.
Materials Science (cond-mat.mtrl-sci)
Acta Materialia, 2026, 313: 122283
Determination of Density Functional Tight Binding Models for Cerium Allotropes
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-04 20:00 EDT
Nir Goldman, Artem Samtsevych, Chiara Panosetti
We have developed Density Functional Tight Binding (DFTB) models for cerium that accurately predict both the electronic band structure and energetic ordering of different allotropes. We show that global optimization of the electronic confining potentials minimize the errors in the predicted Kohn-Sham energies while facilitating determination of a many-body repulsive energy. Our results illustrate the ability of DFTB to accurately reproduce complex f-electron interactions for multiple phases while leveraging minimal Density Functional Theory data.
Materials Science (cond-mat.mtrl-sci)
Main manuscript: 21 pages, 4 figures 2 tables SI: 7 pages, 2 tables
Revealing the origin of XMCD in an altermagnet via three-dimensional control of spins
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-04 20:00 EDT
Daire Mallon, Zixuan Wu, Jheng-Cyuan Lin, Ruiwen Xie, Bo Zhao, Charles Godfrey, Qing He, Lucia Iglesias, Pierluigi Gargiani, Manuel Valvidares, Peter Bencok, Francesco Maccherozzi, Larissa S. I. Veiga, Paul Steadman, Manuel Bibes, Hongbin Zhang, Paolo G. Radaelli, Hariom Jani
Altermagnets are an emerging class of collinear antiferromagnets that exhibit unconventional spin-polarised electronic bands, potentially unlocking new functionalities that do not rely on spin-orbit coupling (SOC). Experimental signatures traditionally associated with spin polarisation, like X-ray magnetic circular dichroism (XMCD), are thus being used as a validation of altermagnetism. However, unlike altermagnetic spin-splitting, these responses require SOC and are not invariant under spin-space rotations. This brings into question the extent to which they can be considered direct signatures of altermagnetism. Here, we exploit the g-wave altermagnet $ \alpha$ -Fe$ _{2}$ O$ _{3}$ to demonstrate that XMCD is governed precisely by the spin-direction-induced symmetry breaking that altermagnetic spin groups are designed to ignore. Strikingly, the XMCD is highly anisotropic and is decoupled from the weak magnetic canting. We show that this anomalous XMCD can be described by on-site Faraday tensors capturing the locally uncompensated spin-orbital anisotropies - a scenario that can be applied to other altermagnets. Leveraging this, we reconstruct complete vectorial maps of nanoscale textures in $ \alpha$ -Fe$ _{2}$ O$ _{3}$ thin films, including domain walls and topological solitons, which are promising for building future spintronics and magnonics devices.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Other Condensed Matter (cond-mat.other)
6 Figures