Mesoscale and Nanoscale Physics
Josephson diode effect in multichannel Rashba nanowires: Role of inter-subband coupling
Ardamon Sten and Sudeep Kumar Ghosh
The Josephson diode effect (JDE) has attracted significant
attention for enabling directional, dissipationless supercurrents, positioning Josephson junctions as promising building blocks for next-generation
quantum devices. Hybrid
semiconductor-
superconductor nanowires provide an experimentally accessible platform for realizing the JDE and hosting Majorana bound states. However, most theoretical treatments assume the single-channel limit, whereas realistic nanowire devices are inherently multichannel due to transverse confinement. Here, we investigate the JDE in multichannel Rashba nanowire Josephson junctions, focusing on the role of inter-subband coupling. We show that subband hybridization qualitatively modifies both the topological phase diagram and the JDE response of the device. In contrast to the single-channel case, the topological phase is confined to a finite window of Zeeman fields, within which Majorana bound states strongly enhance the diode efficiency. Inter-subband coupling also enables a finite JDE even when the Zeeman field is aligned along the
spin-orbit direction – a mechanism absent in independent-channel and strictly one-dimensional nanowire systems. Furthermore, inter-subband coupling enhances spectral asymmetry and significantly increases the diode efficiency compared to single-channel junctions. These results identify inter-subband hybridization as a key ingredient for realizing and optimizing nonreciprocal superconducting transport in experimentally relevant hybrid nanowire Josephson junctions.
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Materials Science · Cross-listed from physics.ins-det
Drift Correction of Scan Images by Snapshot Referencing
Zac Thollar, Kanto Maeda, Tetsuya Kubota et al. (+3 more)
Reliable quantitative analysis in scanning (transmission) electron microscopy (S(T)EM) is often hindered by image drift during long-duration spectral mapping for elemental analysis or for various material functions. We here present snapshot-referencing (SSR) drift correction, a retrospective approach to eliminate spatial distortion based on the temporal nature of the scanning process. A continuous drift vector for every pixel is calculated for a normalized time-field of the scan pattern (e.g., serpentine or raster) utilizing a high-signal, fast-scan "snapshot" as a drift-free reference to guide the correction of simultaneously acquired analytical maps. To describe the drift, we employed Bezier basis functions to model smooth thermal or mechanical drifts and piece-wise linear basis for high-frequency "spiky" shifts such as those caused by charging. We demonstrate the efficacy of this approach on experimental cathodoluminescence (CL)
datasets, showing that it effectively restores spatial integrity to hyperspectral data cubes without the need for specialized hardware. This flexible, software-based solution is broadly applicable to any probe-based analytical technique where a fast imaging signal can be recorded alongside slow spectroscopic data.
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All authors Zac Thollar, Kanto Maeda, Tetsuya Kubota, Taka-aki Yano, Qiwen Tan, Takumi Sannomiya
Materials Science
Multimodal Transformer for Sample-Aware Prediction of Metal-Organic Framework Properties
Seunghee Han, Jaewoong Lee and Jihan Kim
Metal-organic frameworks (MOFs) are a major target of machine-learning-based property prediction, yet most models assume that a single framework representation maps to a single property value. This assumption becomes problematic for experimental MOFs, where samples reported as the same framework can exhibit different properties because of differences in crystallinity, phase purity, defects, and other sample-dependent factors. Here we introduce Experimental X-ray Diffraction Integrated
Transformer (EXIT), a
multimodal transformer for sample-aware prediction of MOF properties that combines MOFid with X-ray diffraction (XRD). In EXIT, MOFid encodes MOF identity, whereas XRD provides complementary information about the experimentally realized sample state. EXIT is pre-trained on one million hypothetical MOFs with simulated XRD to learn transferable representations, leading to improved downstream performance relative to existing approaches. EXIT is fine-tuned on literature-derived experimental
datasets for surface area and pore volume prediction. Incorporating experimental XRD improves predictive performance relative to models without experimental XRD, and
attention analysis and sample-level case studies further show that EXIT assigns different predictions to samples sharing the same MOF identity when their XRD patterns differ. These results establish a practical step from framework-aware to sample-aware MOF property prediction and highlight the value of incorporating experimental characterization into porous materials informatics.
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Strongly Correlated Electrons
Field-induced antiferromagnetic transition in CeIrIn$_5$
Y. Tokunaga, M.-T. Suzuki, S. Krämer et al. (+6 more)
We report low-temperature $^{115}$In
nuclear magnetic resonance (NMR) study of the prototypical heavy-
fermion compound CeIrIn$_5$ in high
magnetic fields applied close to the crystallographic $c$ axis. For this orientation, a field-induced transition was previously reported to take place at about 28 T. Although we do not observe any change of the NMR spectrum above the transition, the intensity of the NMR lines drastically decreases as a consequence of a considerable shortening of the $T_2$ relaxation time. In addition, $1/T_1$ shows a pronounced maximum at the transition. Taking into account previous high-field de Haas-van Alphen results in conjunction with band-structure calculations, our NMR results are most naturally explained by the field-induced transition into an
antiferromagnetic state with the propagation vector $\mathbf{Q} = (1/2, 1/2, 0)$ and
magnetic moments aligned antiferromagnetically along the $c$ axis. This makes CeIrIn$_5$ a unique case where the application of the
magnetic field induces an ordered state with moments antiferromagnetically aligned along the field direction.
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All authors Y. Tokunaga, M.-T. Suzuki, S. Krämer, H. Sakai, S. Kambe, H. Harima, D. Aoki, M. Horvatić, I. Sheikin
Materials Science
True random number generation through stochastic magnonic bistability
Mengying Guo, Zhenyu Zhou, Denys Slobodianiuk et al. (+13 more)
True random number generators (TRNGs) underpin modern cryptography, yet existing implementations face fundamental trade-offs between speed, scalability, and
entropy quality. Here, we demonstrate that
stochastic switching in the bistable regime of
spin-wave dynamics provides a physical
entropy source for high-quality random number generation. Our magnonic random number generator (mRNG), based on a lithography-patterned microstrip on yttrium iron garnet (YIG), exploits thermal fluctuations near the nonlinear bistable regime to generate random bitstreams that pass all 15 NIST SP 800-22 statistical tests at rates with 20 Mb/s. We implement a random-bit multiplier using synchronized mRNG units and demonstrate scalability to 200-nm-wide nanoscale waveguides, establishing
spin-wave bistability as a viable physical
entropy source for integrated random number generation.
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All authors Mengying Guo, Zhenyu Zhou, Denys Slobodianiuk, Roman Verba, Kristýna Davídková, Xueyu Guo, Xudong Jing, Yueqi Wang, Björn Heinz, Yiheng Rao, Carsten Dubs, Caihua Wan, Xiufeng Han, Andrii V. Chumak, Philipp Pirro, Qi Wang
Statistical Mechanics · Cross-listed from quant-ph
Generating pairwise entanglement in periodically driven quantum spin chains with stochastic resetting
Sinchan Ghosh, Manas Kulkarni, K. Sengupta et al. (+1 more)
We show that
stochastic resetting may lead to finite
entanglement between individual, spatially separated
spins (pairwise
entanglement) in the steady state of the
spin chains driven periodically with frequency $\omega_D$. We find the presence of a critical resetting rate $r_c$ below which the steady state pairwise
entanglement, measured via concurrence $C$, vanishes. We also identify an optimal resetting rate $r_m$ at which $C$ becomes maximum. These critical and optimal rates exhibit a non-monotonic dependence on $\omega_D$. Our analysis demonstrates the existence of special drive frequencies at which $r_c$ vanishes and $r_m$ attains minima. We compute $C$ in the presence of
stochastic resetting using exact diagonalization for both the integrable XY model and non-integrable Rydberg
spin chains, which demonstrate these features. Our numerical results match perturbative analytical expressions for the special drive frequencies in the large drive amplitude regime.
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All authors Sinchan Ghosh, Manas Kulkarni, K. Sengupta, Satya N. Majumdar
Strongly Correlated Electrons
Superconducting properties of the three-dimensional Hofstadter-Hubbard model below the critical flux for Weyl points
Pierpaolo Fontana, Luca Lepori and Andrea Trombettoni
The three-dimensional Hofstadter model exhibits a critical rational flux at which Weyl points emerge in the single-particle spectrum. We study the superconducting regime of the model in the presence of a Hubbard attractive interaction by tuning the
magnetic flux across its critical value. We determine the phase diagram in the plane of the coprime pairs parametrizing the
magnetic flux. We show that the system exhibits two distinct regimes separated by a critical flux $\Phi_c$: for $\Phi>\Phi_c$, a semimetal-to-
superconductor quantum phase transition occurs at a finite interaction strength ($U_c\neq0$), while for $\Phi<\Phi_c$ superconductivity arises for arbitrarily weak attraction, with a BCS-like exponential scaling of the gap due to the finiteness of the density of states. Close to the transition, we study the scaling behavior and identify the critical exponents. Our results highlight the interplay between
magnetic band
topology and attractive pairing in three-dimensional Hofstadter systems.
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Materials Science
Electrically steered conduction topologies and period-doubling phase dynamics in VO2
Siyuan Huang, Shuaishuai Sun, Yin Shi et al. (+6 more)
The
insulator-to-metal transition (IMT) in strongly correlated materials, such as vanadium dioxide (VO2), offers a transformative platform for next-generation adaptive electronics and neuromorphic computing. However, harnessing this non-
equilibrium phase transition for deterministic device operation is fundamentally hindered by the inability to disentangle electric-field effects from Joule heating, owing to a lack of operando techniques capable of resolving phase dynamics at nanoscale spatial and sub-nanosecond temporal scales. Here, using a newly developed electrical-pulse-pump ultrafast transmission electron microscope (E-UTEM), we directly visualize the multi-scale electro-thermo-mechanical dynamics of the IMT in suspended VO2 devices. Our results reveal that electric-field-induced Poole-Frenkel (PF) emission, localized by patterned oxygen vacancies, plays a decisive role in redistributing the internal electric field to trigger a deterministic Mott transition. The extreme non-linearity of this PF effect enables the formation of dynamically reconfigurable connectivity
topologies that bypass conventional thermal limits. Furthermore, we observe that the coupling of thermal and elastic energies governs a discrete domain
evolution, characterized by step-wise and period-doubling configurational resets, which is a hallmark of non-
equilibrium phase dynamics in constrained geometries. By integrating experimental imaging with phase-field simulations, we establish a comprehensive framework for the electrically-driven IMT and predict sub-100-ps switching kinetics. These findings provide a fundamental basis for the rational design of ultrafast, low-energy functional devices through nanoscale defect and strain engineering in correlated systems.
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All authors Siyuan Huang, Shuaishuai Sun, Yin Shi, Wentao Wang, Chunhui Zhu, Huanfang Tian, Huaixin Yang, Jun Li, Jianqi Li
Strongly Correlated Electrons
Four-layer charge density waves and chirality in CsV$_3$Sb$_5$
Fernando de Juan and Mark H. Fischer
The kagome
superconductor CsV$_3$Sb$_5$ is the only one in the AV$_3$Sb$_5$ family (A=K,Rb,Cs) that shows a $2\times2\times4$ charge-density-wave (CDW) ground state competing with the more common $2\times2\times2$. In addition, it is also the only one that shows second-harmonic transport and thus broken inversion
symmetry, suggesting these two features are connected. In this work, we test whether the $2\times2\times4$ CDW can break inversion
symmetry by analyzing its stacking energetics with a real-space Ginzburg-Landau free energy. In the limit where each layer is forced to adopt a fixed, threefold symmetric tri-hexagonal configuration, we find an analytical phase diagram mostly occupied by inversion preserving AB and ABCD stacked solutions. Relaxing this rigid layer constraint in a physically meaningful way consistent with ab initio–calculated parameters, we find several new phases including an AABC solution and a distorted ABCD solution, which break inversion and all mirrors and are thus
chiral. However, these phases occupy only small fractions of phase space, suggesting other mechanisms for inversion
symmetry breaking may be at play in CsV$_3$Sb$_5$.
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Mesoscale and Nanoscale Physics
Intra- and Interlayer Excitonic Fine Structure of the Two-Dimensional Perovskite (PEA)$_2$PbI$_4$
Patrick Grenzer, Fabian Lie, Klaus H. Eckstein et al. (+2 more)
Two-dimensional halide perovskites host strongly bound
excitons whose fine structure controls polarization selection rules and radiative recombination, yet several spectral features in (PEA)$_2$PbI$_4$ remain controversially assigned. Here, polarization-resolved low-temperature photoluminescence combined with first-principles G$_0$W$_0$+BSE calculations resolves both the intralayer and interlayer excitonic fine structure of this prototypical n=1 Ruddlesden-Popper perovskite. The low-energy multiplet is consistently described as a purely excitonic intralayer fine structure governed by
crystal symmetry, octahedral distortions, and the two-layer unit
cell, without invoking Rashba or
exciton-polaron mechanisms as the primary origin. A weaker doublet ~45 meV above the bright intralayer states is identified as interlayer
excitons from its agreement with the calculated interlayer
manifold in energy and splitting. Although the static calculations underestimate their oscillator strength and do not reproduce the observed orthogonal polarizations, distortion-induced mixing with bright intralayer
excitons strongly enhances interlayer optical activity and provides a plausible explanation for their visibility. Our results establish interlayer
excitons in (PEA)$_2$PbI$_4$ and refine the excitonic description of fine structure in two-dimensional perovskites.
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All authors Patrick Grenzer, Fabian Lie, Klaus H. Eckstein, Tobias Hertel, Linn Leppert
Mesoscale and Nanoscale Physics · Cross-listed from quant-ph
Thermal-fluctuator driven decoherence of an oscillator resonantly coupled to a two-level system
Thomas J. Antolin, Jonas Glatthard and Andrew D. Armour
Recent experiments on a range of engineered
quantum systems have highlighted the important role of interacting two-level systems (TLSs) in modifying device properties and generating fluctuations. Focusing on the case of an oscillator coupled to a single near-resonant TLS, we explore how interactions between the TLS and lower-frequency thermally activated two-level fluctuators (TLFs) degrade the oscillator's coherence. Depending on the strength of the couplings, a single TLF can give rise to coherence oscillations that appear alongside, or supplant, Rabi oscillations of the oscillator-TLS system. Bath-driven transitions in the TLF cause irreversible coherence decay at a rate that is highly sensitive to both the couplings and the transition rate. For an ensemble of TLFs, we identify and characterise the different regimes of non-exponential phase-averaging-driven coherence decay that the oscillator can display. Using numerical calculations, we examine the extent to which systems with just a few TLFs differ from the limit of a large (continuum) TLF ensemble. Our work provides a theoretical framework for understanding the interplay of coherent TLS interactions and TLF-induced dephasing in
quantum devices such as superconducting and phononic resonators.
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Mesoscale and Nanoscale Physics
Perspective: Quantum Computing on Magnetic Racetrack
Ji Zou, Jelena Klinovaja and Daniel Loss
Magnetic domain walls have long been pursued as carriers of classical information for storage and processing. With the ability to create, control, and probe domain walls at the nanoscale, they are recently recognized as an ideal platform for studying macroscopic
quantum effects and provide a natural blueprint for building scalable
quantum computing architectures. In particular, the experimentally demonstrated high mobility of domain walls makes them not only suitable as stationary
qubits but also as flying
qubits, which may offer advantages over currently explored
quantum computing platforms. In this Perspective, we outline our current understanding of the essential ingredients and key requirements for realizing universal
quantum computation based on
magnetic domain walls. We highlight promising concrete material platforms and identify the experiments that are still needed to advance this concept. We also discuss the potential challenges and point to new opportunities in this emerging research direction at the interface between magnetism and
quantum information science.
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Mesoscale and Nanoscale Physics
Quantum transport in gapped graphene under strain and laser–electrostatic barriers
Hasna Chnafa, Clarence Cortes, David Laroze et al. (+1 more)
Electron transport in
graphene under a
laser-modulated barrier is studied in the presence of an energy gap, a scalar potential, and a uniaxial zigzag strain. The transfer-
matrix approach is used with the boundary conditions to derive the transmission probabilities as functions of different system parameters. Without strain, raising either the energy gap or the potential generally reduces transmission in the central and lower sidebands. Moderate zigzag strain generates pronounced Fano-type oscillations that vanish at large strain, while transmission increases for low potential and decreases for high values. In the upper sideband, the incidence energy shifts the resonance peaks to the right, and growing the barrier width generates characteristic oscillatory patterns. Furthermore, increasing the
laser field amplitude enhances transmission, whereas higher
laser frequencies tend to suppress it. These findings offer new perspectives on controlling electronic transport in gapped
graphene via external fields, strain, and potential applications in optoelectronic devices.
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All authors Hasna Chnafa, Clarence Cortes, David Laroze, Ahmed Jellal
Materials Science · Cross-listed from physics.med-ph
Corneal deformation mapping and FE-based strain analysis via digital image correlation: biomechanical changes after CXL and laser refractive surgery
Benedetta Fantaci, Alejandro Frechilla, Matteo Frigelli et al. (+3 more)
Accurate assessment of corneal mechanical properties is critical for understanding ocular biomechanics, predicting refractive surgery outcomes, and optimizing cross-linking (CXL) treatments. Conventional uniaxial tensile test is limited by non-physiological boundary conditions and simplified stress distributions. Inflation testing more closely reproduces the in vivo stress state but has traditionally lacked full-field deformation mapping. In this work, we present an integrated experimental-computational protocol combining inflation testing of freshly enucleated porcine eyes with high-resolution three-dimensional digital image correlation (3D-DIC). Fifteen corneas were analyzed across three cohorts: (i) de-epithelialized controls, (ii) CXL-treated (standard Dresden protocol), and (iii) anterior stromal ablation via femtosecond
laser. Samples were subjected to controlled intraocular pressure (IOP) elevations up to 40 mmHg. The 3D-DIC approach provided dense, pointwise displacement and strain maps across the anterior surface, successfully quantifying the localized stiffening effects of CXL and the increased compliance induced by stromal ablation. These full-field kinematic data were integrated into a membrane-theory finite element framework to resolve principal in-plane strains, that were used for subsequent inverse modeling to derive anisotropic hyperelastic parameters of porcine corneal tissue. Overall, the method establishes an end-to-end route from physiologic loading to full-field strain mapping and constitutive parameter identification, enabling quantitative evaluation of treatment-induced biomechanical changes in the cornea.
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All authors Benedetta Fantaci, Alejandro Frechilla, Matteo Frigelli, Philippe Büchler, Sabine Kling, Begoña Calvo
Superconductivity
Unveiling the Superconducting Ground State of Heusler alloy Pd2ZrIn via muon spin relaxation and rotation measurement
Kavita Yadav, Anoop M Divakaran, Tsunehiro Takeuchi et al. (+1 more)
Full Heusler
alloys XInPd2 (X= Zr, Hf and Ti) have recently attracted significant
attention owing to their
symmetry-driven electronic structure and also due to the interplay between disorder and emergent ground states. Within this family, Pd2ZrIn serves as a unique platform to study the effect of disorder on superconducting pairing. This
alloy crystallizes in a cubic L21 structure with significant B2-type antisite disorder. Electrical resistivity and
magnetic susceptibility studies confirm bulk type-II superconductivity with a transition temperature TC ~ 2.2 K. Zero-field {\mu}SR results reveal no evidence of spontaneous internal
magnetic fields below TC, confirming the preservation of time-reversal
symmetry. Transverse-field {\mu}SR spectra show the formation of a
vortex lattice, consistent with type-II superconductivity, and the superfluid density is well described by a fully gapped, nodeless s-wave state with superconducting gap {\Delta} (0) ~ 0.33 \pm 0.01 meV. Furthermore, the estimated ratio of transition temperature and
Fermi temperature (TC/TF) indicates that this
alloy lies within the conventional superconducting regime on the Uemura plot. These results establish Pd2ZrIn as a weakly coupled, dirty-limit, type-II
superconductor; with a fully gapped, nodeless order parameter and preserved time-reversal
symmetry.
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All authors Kavita Yadav, Anoop M Divakaran, Tsunehiro Takeuchi, K. Mukherjee
Disordered Systems and Neural Networks
Daydreaming algorithm for Biased Patterns
Mikiya Doi, Masayuki Ohzeki and Federico Ricci-Tersenghi
The Daydreaming
algorithm has been recently proposed in Ref.~\cite{Serricchio2025} as a learning rule that simultaneously reinforces stored patterns and suppresses spurious attractors to improve the storage capacity of the Hopfield model. Its effectiveness has been reported for both uncorrelated and correlated data. However, the existing formulation has mainly assumed unbiased patterns, and the formulation for biased patterns has not yet been sufficiently established. Biased patterns are known to be much more problematic for models of associative
memories. In this study, we reformulate Daydreaming for biased patterns motivated by the underlying rationale of the pseudo-inverse rule. Specifically, we introduce the
retrieval dynamics and an energy function based on the centered representation, and we derive a corresponding update rule for centered Daydreaming. We compare the centered pseudo-inverse rule with centered Daydreaming for biased patterns and examine the
retrieval maps and
eigenvalue distributions of the coupling
matrices. As a result, the centered Daydreaming yields larger basins of attraction than the centered pseudo-inverse rule, and such a beneficial property seems to be due to the broadness of the
eigenvalue spectrum of the coupling
matrix. To better understand this connection, we construct modified coupling
matrices whose spectra interpolate between a pseudo-inverse-like spectrum and the Daydreaming one. The results clearly indicate that the broader spectrum generated by Daydreaming contributes to the enlarged basin of attraction.
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Statistical Mechanics
Self-propulsion protocols for swift non-equilibrium state transitions and enhanced cooling in active systems
Kristian Stølevik Olsen and Hartmut Löwen
A control framework is proposed for inducing non-
equilibrium state transitions in confined active matter, where the statistics of self-propulsion serve as the only control parameter. Positivity of the noise amplitudes and fundamental bounds on position-propulsion correlations define the admissible control space and impose speed-limits on transitions between non-
equilibrium states. We show that non-stationary initial states facilitate additional speed-ups, corresponding to pre-loading the state with negative correlations. This enables active cooling protocols that outperform their passive counterparts.
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Statistical Mechanics
Spectral Signatures of Third-Order Pseudo-Transitions in Finite Systems: An Eigen-Microstate Approach
Wei Liu, Songzhi Lv, Xin Zhang et al. (+3 more)
Third-order pseudo-transitions in finite systems reflect reorganization beyond conventional criticality, yet their identification usually relies on microcanonical
entropy, which is often inaccessible in practice. Here we introduce a spectral generalized response within the eigen-microstate framework. From the distribution of normalized spectral weights, we construct the third-order ratio $R_3=K_3/(K_2)^3$, which probes asymmetric redistribution among fluctuation modes beyond leading-mode condensation. Across Ising and Potts models on regular
lattices and random regular networks, extrema of $R_3$ consistently track higher-order anomalies. Combined with spectral projection, the method further distinguishes dependent and independent branches: the former remain tied to the dominant ordering channel, whereas the latter arise from redistribution within the subleading fluctuation subspace. The effective spectral dimension $R_{\mathrm{eff}}$ provides the participation background in which these anomalies develop. These results establish a
geometric characterization of third-order pseudo-transitions as reorganizations of statistical weight in configuration space and provide an order-parameter-free route to finite-size structural criticality.
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All authors Wei Liu, Songzhi Lv, Xin Zhang, Fangfang Wang, Kai Qi, Zengru Di
Mesoscale and Nanoscale Physics
Emergence of rigid Polycrystals from atomistic Systems with general Interactions
Leonard Kreutz and Timo Ziereis
We investigate the formation of polycrystalline structures in a class of particle systems. The atomistic energy is modeled as a sum of particle energies that favor atoms being locally isometric to a reference
lattice. The discrete frame invariant energy allows for particle configurations in which no underlying
lattice is assumed a priori. We prove a discrete-to-continuum limit for configurations with finite surface-energy scaling by means of $\Gamma$-convergence. The resulting continuum theory is described by piecewise constant fields encoding the local orientation of the configuration. The limiting energy is concentrated on grain boundaries, corresponding to the interfaces between regions where the microscopic configuration has constant orientation. The associated energy density depends on the orientations of the two grains as well as on the normal to the interface. Due to our assumptions on the rigid interactions, solid-solid phase transitions with interpolating boundary layers are not energetically favorable; the energy density therefore decomposes into twice the energy density for solid-
vacuum transitions.
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Materials Science
Rippled graphene pores as fluidic memristive devices with synaptic and neuromorphic functionalities
Wenzhe Zhou, Dongjiao Ge, Ao Zhang et al. (+8 more)
Nanofluidic memristive devices work with nanoscale pores and ions dissolved in water, which harness the ionic
memory effect aiming to store and process information. These devices share the same charge carriers as biological systems and bring hope for better emulating the neural functions and developing ionic
circuits for neuromorphic applications. Specially, theory and experiments suggest that nanoconfinement is essential for inducing a
memory effect, which places limit on the pore size to nm-scale or smaller. Such devices are difficult to scale up with precision and operate with long-term stability. Here, we show that a micrometer size pore, generally expected to exhibit a linear ion transport, can display a pronounced
memory effect, if its rim is wrapped by strongly curved and tightly stacked
graphene. We attribute the observation to slow ion dynamics confined in the rippled
graphene edges. The devices are easy to scale up and integrate into fluidic
circuits. The
memory effect is ion-selective and exhibits long endurance comparable to the lifetime of synaptic
proteins, which enables reversible modification of the conductance states using programmable voltage spikes and various electrolytes over a long time, akin to biological synaptic plasticity. Thanks to this plasticity, our devices and their integrated
circuits enable storing, transmitting and processing information with high reliability, fidelity and accuracy, as evidenced in the identification of both greyscale and color images, and in the real-time analysis of emulated neural signals. Our results highlight nanoscale morphology of the pore wall as an important parameter regulating ion transport and indicate that the stringent nanoconfinement for ionic
memory can be lifted from restricting the pore size to designing its rim structure. The devices and their integrated
circuits may find use in ionic neuromorphic applications.
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All authors Wenzhe Zhou, Dongjiao Ge, Ao Zhang, Jincheng Xu, Yu Ji, Yiran Gong, Wenchang Zhang, Jidong Li, Li Lin, Zhiping Xu, Pengzhan Sun
Materials Science
From Entropy to Compression: Competing Thermodynamic Drivers of Structural Transitions in Transition Metals
S. Azadi, S.M. Vinko, A. Principi et al. (+2 more)
Solid-solid phase transitions in metals are traditionally driven by changes in density or external pressure. Here we show that, under strong electronic excitation, structural stability is governed by the interplay between electronic effects and compression. Using finite-temperature density functional theory, we construct pressure-temperature phase diagrams for 15 metals spanning hcp-, fcc-, and bcc-ground-state structures. The results reveal a systematic reduction of structural diversity with increasing electronic temperature, with stability increasingly dominated by the fcc structure, while hcp remains a persistent secondary phase and bcc stability is progressively suppressed. At elevated temperatures, fcc is broadly favored, whereas bcc is stabilized primarily by compression, leading to a material-dependent competition across the periodic table. These findings provide a unified framework for understanding structural transformations in electronically excited metals and highlight the importance of considering both electronic excitation and pressure in describing phase stability far from
equilibrium.
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All authors S. Azadi, S.M. Vinko, A. Principi, T.D. Kuehne, M.S. Bahramy
Superconductivity
Pseudogap and Condensation in Cuprate Superconductors from NMR Shifts
Abigail Lee and Juergen Haase
The electronic properties of the high-temperature superconducting cuprates are encoded in complex sets of NMR data, but without microscopic theory, reliable NMR phenomenologies are in demand. Early analyses of NMR could only focus on very few materials and discovered
spin singlet pairing and the enigmatic pseudogap. However, a coherent phenomenology of shift and relaxation could not be established, as incoming data from other cuprates complicated the picture. Today, due to work of many groups worldwide, planar copper and oxygen NMR data are available for most cuprates. Here, based only on
symmetry of the two Cu hyperfine couplings, an anisotropic $A_\alpha$ and isotropic $B$, the Cu shifts are disentangled, and two different shift components emerge. Upon doping the cuprates, metallic B-
spins are created above the pseudogap temperature which is shared with metallic A-
spins. Further doping decreases the pseudogap temperature and increases the B-
spin, but less so the A-
spin. The apparent linear rate of increase in density of states of the B-
spin with doping increases nearly threefold above about $x=0.20$, where the pseudogap has disappeared and A and B turn into superconducting metals, i.e. they disappear rapidly at $T_\mathrm{c}$. The pseudogap temperature is a measure of the coupling between A and B, which suppresses the shifts but not
nuclear relaxation.
Spin singlet pairing involves A and B according to three simple rules for condensation which will be discussed. The optimal $T_\mathrm{c}$ demands a special match between A and B and involves systems with a pseudogap. However, the highest $T_\mathrm{c}$ of all cuprates is not encoded in the shift, but rather in
nuclear relaxation and charge sharing between planar Cu and O. Relations to other probes are discussed.
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Mesoscale and Nanoscale Physics
When heat goes astray – non-local heating in a semiconductor
Mahmoud Elhajhasan, Elena Trukhan, Katharina Dudde et al. (+8 more)
Heating of
semiconductor devices limits their performance and lifetime, which must be addressed by thermal management starting at the heat source. It is a common assumption that the heat source and the resulting heat spot locally coincide, if their size exceeds the mean free paths of the main heat carriers, the
phonons. We show that this paradigm of heat locality breaks down on length scales spanning several micrometers. As a consequence, non-local heating occurs in contradiction to
Fourier's law. Therefore, we heat laterally structured
semiconductor membranes that feature a rising number of interfaces with a well-focussed
laser and map-out
lattice temperatures by Raman thermometry. Remarkably, the non-local heating can exceed the
laser-induced local heating, which we attribute to ballistic
phonon transport far above cryogenic temperatures.
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All authors Mahmoud Elhajhasan, Elena Trukhan, Katharina Dudde, Guillaume Würsch, Jana Lierath, Ian Rousseau, Raphaël Butté, Nicolas Grandjean, Nakib Haider Protik, Giuseppe Romano, Gordon Callsen
Mesoscale and Nanoscale Physics
Optical conductivity of topological semimetal Nb$_{2n+1}$Si$_n$Te$_{4n+2}$
Seongjin Ahn
We study the linear optical conductivity of the Nb$_{2n+1}$Si$_n$Te$_{4n+2}$ family of layered van der Waals materials, which has recently gained considerable
attention owing to its dimensionality-tunable electronic structure with a quasi-one-dimensional nodal-line state. At zero temperature, we analytically show that the Drude weight exhibits strong anisotropy: along the nodal-line direction it is finite at charge neutrality, whereas in the transverse direction it vanishes quadratically with
Fermi energy. On the other hand, the interband optical conductivity exhibits the same linear frequency dependence along both the longitudinal and transverse directions, with only a direction-dependent slope in the low-frequency regime. We further analyze the leading finite-temperature corrections to the intraband and interband optical conductivities, showing that the zero-temperature results remain valid up to experimentally relevant temperatures.
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Mesoscale and Nanoscale Physics
Coherent Microwave Driving of Domain Wall Depinning in a Ferrimagnetic Garnet
Hanchen Wang, Laura van Schie, Adam Erickson et al. (+6 more)
Coherent control of domain wall dynamics offers a route to fast manipulation of
magnetic textures beyond thermally activated motion. We demonstrate resonant excitation of linear and nonlinear dynamics of a pinned domain wall in a ferrimagnetic garnet thin film driven by a microwave field. Using scanning nitrogen-vacancy magnetometry and nonlocal
spin-pumping measurements, we identify a low-frequency mode inside the
magnon gap, originating from the localized oscillatory motion of a domain wall across a pinning line defined by a Pt stripline. Upon increasing the microwave drive into the nonlinear regime, this mode enables domain wall depinning at reduced external
magnetic fields. Micromagnetic simulations reveal a progression from localized oscillations to partial relocation between pinning sites and, ultimately, complete escape from the pinning region with increasing driving power. These results establish resonant excitation of domain walls at engineered pinning sites as a mechanism for manipulating
magnetic textures via localized nonlinear dynamics.
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All authors Hanchen Wang, Laura van Schie, Adam Erickson, Lauren J. Riddiford, Davit Petrosyan, Christian L. Degen, Richard Schlitz, William Legrand, Pietro Gambardella
Strongly Correlated Electrons
Daesik Kim, Hyojae Jeon, Seongjun Park et al. (+3 more)
The scalar
spin chirality (SSC), whose nonzero value $\langle {\bf S}_i \cdot ({\bf S}_j \times {\bf S}_k) \rangle \neq 0$ implies the breaking of time-reversal and certain point-group
symmetries in the ground state, is a key quantity characterizing
chiral magnetism in both classical and
quantum settings. The classical SSC is manifested, for instance, in skyrmion
crystal phase, while the
quantum SSC is still highly sought after in various frustrated
spin-1/2 models. An interesting possibility that has not been explored so far is the case in which SSC is
symmetry-wise allowed, yet remains zero classically due to the collinear or coplanar arrangement of
spins, but is generated by virtue of
quantum fluctuation. We demonstrate the existence of precisely such a phase in a
spin-1/2 triangular-
lattice model with XXZ interaction,
spin-orbit-induced exchange interactions, and an external
magnetic field. Using iDMRG, we thoroughly map out the phase diagram of the model and identify several phases with coexisting
magnetic order and SSC. The nonzero SSC arises despite the classical
magnetic order being collinear or coplanar. We provide detailed
magnon analysis to ascribe its origin to
quantum fluctuations around classical
magnetic order. The estimate of SSC from
magnon analysis agrees with iDMRG results quantitatively. We map out the
magnon spectrum and its Berry
curvature, culminating in the prediction of finite thermal
Hall conductivity in these phases with SSC.
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All authors Daesik Kim, Hyojae Jeon, Seongjun Park, Seungho Lee, Jung Hoon Han, Hyun-Yong Lee
Strongly Correlated Electrons
Triple-${\bf Q}$ collinear state with compensated ferrimagnetic nature on frustrated kagome lattice
Kazushi Aoyama and Hikaru Kawamura
Spin-selective band splitting without net magnetization and
spin-orbit couplings serves for a next-generation
spin-current generator, and its typical platforms are altermagnets and compensated ferrimagnets as well, where the existence of a
crystal asymmetry or nonequivalent sites is essential. Here, we theoretically demonstrate that such a splitting can be realized in a triple-Q 12-sublattice state emerging in a $J_3$-dominant kagome antiferromagnet, without the help of the
crystal asymmetry. Reflecting the multi-sublattice nature, a local magnetization reveals a fully compensated ferrimagnetic pattern in units of a triangle plaquette, leading to $s$-wave-type
spin splittings in
magnon and electron bands. This enables an atiferromagnetic
spin Seebeck effect at zero field in insulating systems and filling-controlled polarized states in metallic systems, highlighting the potential of frustrated magnets to realize novel spintronics functionalities.
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Materials Science
Controlling Quantum Materials by Growth: Thermodynamics, Kinetics, and Defect Engineering in Transition Metal Dichalcogenides
Anzar Ali, Md Ezaz Hasan Khan and Mahmoud Abdel-Hafiez
Transition metal dichalcogenides exhibit a wide range of semiconducting, metallic, correlated, and topological electronic states that arise from strong coupling between
lattice structure, dimensionality, and electronic degrees of freedom. In these materials,
crystal growth is not merely a preparative step but a thermodynamic boundary condition that establishes chemical potentials, defect populations, polytype stability, and access to metastable phases. As a result, synthesis determines the structural and defect landscape from which collective electronic behavior emerges. In this Review, we develop a unified thermodynamic and kinetic framework that connects growth conditions to phase stability, defect energetics, and microstructure. We examine how chemical potential constraints define stability windows, how supersaturation and mass-transport regimes govern nucleation and morphology, and how nonequilibrium pathways enable kinetic trapping and polymorph selection. Bulk and thin-film synthesis approaches, including chemical vapor transport, flux growth, physical vapor transport, solvent-assisted crystallization, chemical vapor deposition, and molecular beam epitaxy, are placed within a common thermodynamic and kinetic map to clarify how distinct growth regimes produce characteristic disorder profiles and structural phases. By explicitly linking synthesis variables to charge-density-wave order, superconductivity, band
topology, and correlation effects, this Review establishes
crystal growth as a central parameter in determining the effective electronic
Hamiltonian realized in experiment. This perspective provides a physically grounded framework for improving reproducibility and guiding deterministic control of emergent
quantum phases in layered materials.
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Materials Science
Discovery of Graphene Sheets and C-Rich Micro-Oval structure in Stingless Bee Hive; Leading to an Emergent Material with Debut of Blue Emission
Manas Kumar Dalai, Ankita Mahakhuda and Abinash Prusty
Naturally produced stingless bee hive (NP-SBH) is an intricately produced material by the combination of waxes, resin and other biological materials that offers protection and structural stability to the bee colony. This study explores a detailed analysis of Indian stingless bee hive material using multi-characterization techniques approach to evaluate their morphological, ultrastructural, chemical composition and their crystallinity. FESEM reveal uniformly distributed micro-oval structures along with
graphene sheets throughout the observed region. Furthermore, Energy Dispersive X-ray Analysis (EDAX) provides the richness of carbon (C) in
graphene as well as in the micro-oval structure. HRTEM gives an insight about the internal ultrastructure and arrangement of atoms in the sample which revealed the presence of multiple
graphene sheets. The ring shape electron diffraction pattern and high resolution
lattice fringes provide the arrangement of carbon atoms, with interlayer spacing (d) value 3.4 Å, well agreed with that of
graphene. Furthermore, X-ray Diffraction (XRD) and
Fourier Transform Infrared (FTIR) spectroscopy support the presence of
graphene. As a debut, we observe blue emission from PL spectroscopy with decay times 1.18 ns (42 %) and 5.41 ns (58 %).
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Statistical Mechanics · Cross-listed from hep-th
M. Reza Mohammadi Mozaffar and Ali Mollabashi
We investigate
symmetry-resolved
entanglement in non-relativistic
quantum field theories, including complex Lifshitz scalar chains and Lifshitz fermionic models. Using charged moments and the correlator method, we compute
symmetry-resolved Renyi and von Neumann
entropies and analyze their dependence on subsystem size, charge, mass, and the dynamical exponent z. Our results reveal distinct features of non-relativistic
entanglement. In Lifshitz scalar theories, approximate equipartition among charge sectors emerges in the large-z regime, with configurational
entropy dominating, whereas Lifshitz fermionic models exhibit genuine equipartition only in the relativistic limit, with fluctuation
entropy prevailing. These findings highlight a rich interplay between conserved charges, subsystem size, mass, and dynamical scaling, and provide a framework to explore operationally accessible
entanglement in non-relativistic systems. Our study offers insights relevant to experimental platforms such as cold atom setups and mesoscopic systems, where particle-number-resolved measurements can probe
symmetry-resolved
entanglement.
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