Materials Science
Single-crystal growth and magnetic, magnetoelectric, and optical properties of ferroaxial-type SrMn$_2$Ni$_6$Te$_3$O$_{18}$
Ryoya Nakamura, Shinichiro Asai, Yusuke Nambu et al. (+2 more)
Single
crystals of SrMn$_2$Ni$_6$Te$_3$O$_{18}$, a member of the ferroaxial-type
magnetic oxide family $AB_{2}C_{6}$Te$_3$O$_{18}$ ($A$ = Pb, Sr; $B$ = Mn, Cd; $C$ = Ni, Co), have been successfully grown, and their structural,
magnetic, magnetoelectric, and optical properties have been systematically studied. Imaging of the spatial distribution of electric-field-induced optical rotation reveals that the single
crystals preferentially form single ferroaxial (FA) domains. Magnetization and
neutron diffraction measurements show that Mn$^{2+}$ and Ni$^{2+}$
magnetic moments order antiferromagnetically at $T_{\rm N}$ = 83 K, forming a $c$-axis collinear bidirector-type
antiferromagnetic structure. All independent magnetoelectric tensor components allowed by the
magnetic point group 6/$m^{\prime}$ have been detected, and the $\chi_{33}$ component exhibits a pronounced temperature-dependent anomaly, including a peak and a sign reversal. Preferential formation of single FA domains and a similar $\chi_{33}$ anomaly are also observed in the isostructural compound PbMn$_2$Ni$_6$Te$_3$O$_{18}$. These findings suggest that the ferroaxial and
magnetic characteristics within this structural framework are robust against Sr-Pb replacement.
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All authors Ryoya Nakamura, Shinichiro Asai, Yusuke Nambu, Takatsugu Masuda, Kenta Kimura
Soft Condensed Matter
Continuum granular flow model with restitution-derived viscoelastic damping
Bodhinanda Chandra, Sachith Dunatunga and Ken Kamrin
This work presents a unified viscoelastic-viscoplastic continuum framework for modeling rate-dependent granular flows across regimes. The formulation incorporates two distinct rate-dependent mechanisms, namely micro-inertia and viscoelastic dissipation, within a single continuum description. A central contribution is an explicit link between the coefficient of restitution and a continuum viscosity, derived from an analysis of wave attenuation in granular assemblies, thereby establishing a direct connection between particle-scale collision physics and macroscopic damping. This relation is introduced while retaining inertia-dependent plastic flow governed by the classical $\mu(I)$ rheology. The constitutive model is constructed by meticulously partitioning elastic and plastic responses within the model and corresponding stress-update routine, such that viscous dissipation governs wave propagation and collisional processes without altering the plastic flow rule. The framework is implemented within the material point method to simulate transient processes involving large deformations, material separation, and subsequent reconsolidation. A range of numerical examples, including steady, transient, vibrational, and impact-driven flows, demonstrates that the model captures wave propagation,
diffusion, and rate-dependent granular behavior within a unified continuum setting.
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Disordered Systems and Neural Networks · Cross-listed from physics.soc-ph
Disorder Crossover in Urban-Front Growth
Martin Hendrick, Maximilian Trique and Gabriele Manoli
Urban expansion fronts display a robust local roughness exponent together with strongly dispersed growth and nonuniversal dynamic exponents. We show that this coexistence can arise from a disorder-controlled crossover in projected-front growth. Introducing a minimal Eden model, in which geographic constraints act as quenched dilution and coalescence as quenched local acceleration, we demonstrate that the resulting front enters a long disorder-dominated preasymptotic regime, whose scaling near threshold is set by ordinary two-dimensional percolation. In this regime, the local roughness remains close to $1/2$, while the large-scale exponents vary broadly with disorder and acceleration. These results provide a minimal explanation of urban-front roughening and suggest a more general mechanism for
stochastic growth in heterogeneous media.
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Strongly Correlated Electrons
Decomposing Fractional Quantum Hall Wave Functions via Operator Contraction Multiplication
Dong-Hao Guan, Licheng Wang, Yuan Zhou et al. (+2 more)
We develop a general algebraic scheme to decompose fractional
quantum Hall (FQH) wave functions based on the operator contraction multiplication. By introducing fermionic and bosonic operators and establishing three fundamental contraction rules, we achieve an exact decomposition of Laughlin states. This approach naturally extends to multi-component systems by factorizing coupled Jastrow factors via resultants and elementary symmetric
polynomials, enabling the first complete decomposition of Halperin states. For Halperin ($2,2,1$) state, we explicitly derive its basic expansion, identify root configurations, and reveal intra- and inter-color squeezing operators, thereby uncovering the underlying generalized Pauli principle. Using this method, we compute orbital
entanglement spectra for up to $16$ particles with decomposition dimensions exceeding $10^{11}$, obtaining edge excitation sequences that precisely match
chiral Luttinger
liquid theory. Our framework breaks through the longstanding limitations of Jack
polynomials, provides a unified decomposition for both single- and multi-component FQH states, and opens a new avenue for exploring wave functions for more complex FQH states.
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All authors Dong-Hao Guan, Licheng Wang, Yuan Zhou, Ai-Lei He, Yi-Fei Wang
Materials Science
GEWUM: General Exploration Workflow for the Utopia of Materials: A Unified Platform for Automated Structure Generation, Selection, and Validation
Jiexi Song, Aixian She, Changpeng Song et al. (+3 more)
The fragmented landscape of existing computational tools often hinders the seamless integration of large-scale structure prediction with rigorous stability validation. To address this, we present GEWUM (General Exploration Workflow for the Utopia of Materials), an open-source platform that integrates the Selective Random Structure Search (SRSS) strategy with universal Machine Learning Interatomic Potentials (uMLIPs) to automate and accelerate materials discovery. With native support for SLURM-based HPC clusters, GEWUM unifies the entire workflow from structure generation and diversity-preserving selection to thermodynamic/dynamic stability assessments and property calculations. The platform further incorporates built-in visualization tools, including Sankey diagrams for space-group
evolution, violin plots for energy distributions, and t-SNE/UMAP
embeddings for structural diversity, enabling intuitive interpretation of screening results. We demonstrate GEWUM through three case studies: low-energy polymorph prediction in Al-Sc-N, identification of a P-62c phase of U3Si5, and high-pressure structure prediction of ThH10 at 150 GPa.
Benchmark tests confirm reasonable agreement in thermophysical property predictions.
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All authors Jiexi Song, Aixian She, Changpeng Song, Diwei Shi, Fengyuan Xuan, Chongde Cao
Materials Science
Identifying Oriented Spin Space Groups and Related Physical Properties Using an Online Platform FINDSPINGROUP
Yutong Yu, Xiaobing Chen, Yanzhou Zhu et al. (+5 more)
Unconventional magnets that combine
antiferromagnetic structures with
ferromagnetic-like responses are essential for the development of next-generation spintronics. Their emergent properties are fundamentally dictated by the interplay between exchange-driven
magnetic geometry and
spin-orbit coupling, which are described by
spin space group (SSG) and
magnetic space group (MSG) frameworks, respectively. However, the lack of direct correspondence between these frameworks, developed in different eras, hinders the systematic tracking of
symmetry evolution of these intertwined physical contributions. In this work, we introduce FINDSPINGROUP, a computational architecture that implements the recently emerged, oriented
spin space group framework to unify SSG and MSG descriptions. By automating the tracking of
symmetry-breaking pathways from the non-relativistic to the relativistic limit, this online platform enables the classification of
magnetic phases and the derivation of
symmetry-constrained tensors for phenomena such as momentum-dependent
spin splitting and the anomalous
Hall effect. By standardizing data exchange through the
spin crystallographic information file, this architecture establishes a computational infrastructure for the high-throughput discovery and design of unconventional magnets.
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All authors Yutong Yu, Xiaobing Chen, Yanzhou Zhu, Yuhui Li, Renzheng Xiong, Jiayu Li, Yuntian Liu, Qihang Liu
Materials Science
Navigating Order-(Dis)Order Family Trees via Group-Subgroup Transitions
Shuya Yamazaki, Yuyao Huang, Martin Hoffmann Petersen et al. (+2 more)
As closed-loop materials discovery systems scale to produce millions of candidate compounds, the credibility of the novelty they reward becomes a critical concern. Novelty is commonly assessed against databases of ordered
crystal structures, in which atomic sites are fully occupied. Yet, a predicted ordered structure may simply correspond to a particular ordering of a known disordered phase, whose sites are occupied by multiple species in the statistical average structure; we refer to such a structure as an ordered child of a disordered parent. Here, we introduce order-(dis)order family trees, a
symmetry-based framework that organizes ordered and disordered structures through group-subgroup relations and enables novelty to be explicitly evaluated. We develop a high-throughput family matching procedure, to identify possible disordered parents and
symmetry-related ordered relatives for a given ordered structure. As validation, we test our framework on synthesis-facing case studies (A-Lab), where it correctly recovers existing disordered parents for the targeted ordered structures. Extending this family-tree-based
benchmark to experimental structure databases (ICSD), computational
datasets (MP-20, Alex-MP-20, and GNoME), and
crystal generative models further reveals that many ordered structures that appear novel as individual entries are, in fact, better understood as members of experimentally known order-(dis)order family trees. We also show that this is particularly evident in
symmetry-agnostic all-atom generative models, which more frequently produce ordered structures derived from known disordered parents, whereas
symmetry-constrained models are 2-4x less prone to this behavior. Our results establish order-(dis)order family trees as a key requirement for achieving genuine novelty in data-driven materials discovery.
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All authors Shuya Yamazaki, Yuyao Huang, Martin Hoffmann Petersen, Wei Nong, Kedar Hippalgaonkar
Materials Science · Cross-listed from physics.optics
Analytic Inverse Design of Temporal Metamaterials via Space-Time Duality
Giuseppe Castaldi, Marino Coppolaro, Massimo Moccia et al. (+3 more)
Temporal metamaterials, created by modulating the refractive index in time, offer powerful means of controlling wave propagation but still lack a systematic design methodology. Here, we develop an analytic inverse-design framework rooted in space-time duality and the established theory of one-dimensional spatial inverse scattering. By prescribing reflection (backward-wave) and transmission (forward-wave) responses in rational-function form, we obtain closed-form refractive-index modulations that are guaranteed to be physically admissible. This approach avoids iterative optimization and provides direct analytic control of the modulation. We illustrate the method with syntheses of mathematical operators, such as derivatives and integrals, as well as Chebyshev- and Butterworth-type filters, and validate the results through finite-difference time-domain simulations. Our findings establish a general route to temporal media with tailored functional and spectral responses, enabling applications in wave-based information processing, programmable filtering, and amplification schemes inspired by photonic time
crystals.
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All authors Giuseppe Castaldi, Marino Coppolaro, Massimo Moccia, Carlo Rizza, Nader Engheta, Vincenzo Galdi
Statistical Mechanics
Time-Uniform Error Bound for Temporal Coarse Graining in Markovian Open Quantum Systems
Teruhiro Ikeuchi and Takashi Mori
Several approximation procedures, such as the full or partial rotating-wave, time-averaging, and
geometric-arithmetic approximations, have been proposed to derive Gorini-Kossakowski-Sudarshan-Lindblad (GKSL) generators from the Born-Markov
quantum master equation (e.g., the Redfield equation). Establishing rigorous error bounds for these approximations is of fundamental and practical importance. However, existing bounds face two major limitations: they are highly specific to individual methods, and, more critically, they diverge in the long-time limit, ensuring the accuracy of the derived GKSL generator only in short-time regimes. In this Letter, we resolve both issues by deriving a unified, rigorous error bound for a general class of approximation methods – termed temporal coarse graining – that encompasses all aforementioned schemes. Crucially, our error bound is time-uniform. This guarantees that GKSL generators obtained via temporal coarse graining remain accurate for arbitrarily long times, provided the dissipation timescale is significantly longer than the bath correlation timescale.
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Mesoscale and Nanoscale Physics
Collective Excitations and Stability of Nonequilibrium Polariton Supersolids
A. Grudinina, J. Cao, A. Kavokin et al. (+2 more)
Formation of nonequilibrium counterparts of supersolids, simultaneously characterized with spontaneous superfluid and crystalline order, was recently reported in incoherently pumped polariton condensates. We investigate collective excitation spectra of this phase and explicitly demonstrate the emergence of gapless Nambu-Goldstone modes due to spontaneously broken continuous phase and translation
symmetries. For the recent implementation of the polariton nonequilibrium supersolidity in
semiconductor metasurfaces [D. Trypogeorgos et al., Nature 639, 337 (2025)], we demonstrate the key role of attractive polariton interactions, mediated by the excitonic reservoir, for stability of the supersolid phase. Performing a thorough numerical investigation, we identify the conditions for existence of the diagonal and off-diagonal long-range order in negative-mass nonequilibrium supersolids.
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All authors A. Grudinina, J. Cao, A. Kavokin, N. Voronova, A. Nalitov
Statistical Mechanics
Fractals of Simple Random Walks in Two Dimensions: A Monte Carlo Study
Jiang Zhou, Ziru Deng and Pengcheng Hou
We present a Monte Carlo study of the fractal geometry of clusters formed by discrete-time simple random walks (sRW) of $L^2$ steps on a periodic square $L\times L$
lattice. We verify with high precision that the asymptotic behavior of the cluster mass follows $M/L^2 \simeq (\ln L)^{-1} [\frac{\pi}{2}+b (\ln L)^{-2}]$, with $b\approx -(\pi/2)^{-2}$, demonstrating marginal “logarithmic fractals". We further determine the fractal dimension of the hull to be $d_{\rm hull}=1.333\,29(14)=4/3$, in excellent agreement with the prediction of Schramm-Loewner
evolution ($\rm SLE_{8/3}$) for the Brownian frontier universality class. More importantly, we analyze the chemical distance $S$ spanning the cluster and obtain strong evidence that it asymptotically scales as $S\sim L(\ln L)^{1/4}$, lying exactly on the theoretical upper bound for the chemical distance for level-set percolation clusters on the two-dimensional Gaussian free field. Our numerical results show that the sRW cluster exhibits a conformally invariant external frontier and contains highly efficient asymptotically linear connective paths.
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Strongly Correlated Electrons
Pressure-Tuned Competing Electronic States in Layered Tellurides
Mahmoud Abdel-Hafiez, Govindaraj Lingannan, D. A. Chareev et al. (+7 more)
Layered transition-metal dichalcogenides (TMDs) host competing electronic states that can be tuned by external perturbations, providing a platform to explore the interplay between disorder, electronic structure, and
quantum transport. Here we investigate magnetotransport in bulk semiconducting 2H-MoTe2 under hydrostatic pressure. At ambient pressure, transport evolves from high-temperature metallic behavior into activated conduction and ultimately a strongly localized variable-range hopping regime, accompanied by a pronounced magnetotransport anomaly near 45 K and large, nonsaturating magnetoresistance extending up to an unprecedented field of 60 T in semiconducting 2H-MoTe2. Under compression to 15.6 GPa, the insulating state is rapidly suppressed and a low-resistivity regime emerges in which
quantum interference dominates, exhibiting a crossover from weak antilocalization (WAL) to weak localization (WL) at low temperatures. A physically motivated phenomenological description captures the magnetoresistance across these regimes and yields a characteristic electronic length scale that remains comparable across the localized and
quantum-interference regimes. First-principles calculations reveal a continuous pressure-driven collapse of the bandgap into a semimetallic electronic structure. These results establish a unified picture of pressure-tuned transport spanning hopping and
quantum-coherent regimes.
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All authors Mahmoud Abdel-Hafiez, Govindaraj Lingannan, D. A. Chareev, A. N. Vasiliev, Anas Abutaha, Kadir Can Dogan, Mehmet Yagmurcukardes, Mehmet Egilmez, Hasan Sahin, Sami El-Khatib
Strongly Correlated Electrons
$\eta$-pairing in a two-band model of spinless fermions
Igor N. Karnaukhov
We study the two-band model of spinless
fermions in which itinerant
fermions interact with localized
fermions through the two-particle hybridization. In 1D version, the model has exact solution using the Bethe ansatz. It has been shown that accounting for two-particle hybridization reduces the repulsive interaction between itinerant
fermions. In the case of strong interaction, the effective interaction between itinerant
fermions is attractive, and $\eta$-pairing of spinless
fermions is realized. The proposed pairing mechanism via two-particle hybridization can lead to $p$-superconducting states with $\eta$-pairing. $\eta$-pairing of spinless
fermions could explain the phenomenon of high-temperature superconductivity experimentally observed in hydrogen-rich materials at high pressures.
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Strongly Correlated Electrons
Condensate states in Fermi and Bose-Hubbard ladders
F. X. Liu, E. S. Ma and Z. Song
Although neither hardcore
bosons nor
fermions can occupy the same single-site state, they still obey different statistics, resulting in distinct many-particle
quantum states, such as condensate states versus
Fermi-
liquid states. However, when only pair states are considered, the two can take the same form, since a local hardcore Bose pair and a
Fermi pair obey the same statistics. In this work we demonstrate this by studying both
Fermi and Bose extended Hubbard ladders, which can be realized experimentally in synthetic atomic ladders. A set of exact condensate-pair eigenstates for the
Fermi ladder is constructed under SU(2)
symmetry and can then be obtained by the spectrum generating
algebra. The corresponding hardcore
boson counterpart can be simply obtained by replacing fermionic operators with hardcore bosonic ones. Nevertheless, the
boson-pair eigenstates are associated not with
symmetry but with the restricted spectrum generating
algebra. We also investigate the effect of next-nearest-neighbor hopping on the condensate states through numerical simulations of the dynamic response. The conclusions can be extended to a two-layer system. Our result reveals not only the resemblance of
fermions to hardcore
bosons, but also a possible mechanism of
Hilbert-space fragmentation.
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Mesoscale and Nanoscale Physics
Higher odd-order nonlinear Hall effect in magnetic topological insulator Mn(Bi1-xSbx)2Te4
Xiubing Li, Zheng Dai, Shuai Zhang et al. (+10 more)
The nonlinear
Hall effect is a new member of the
Hall effect family, which attracts intense research interests, and it is closely related to the
quantum geometry of
quantum materials. The previous studies primarily concentrate on the second-order and third-order nonlinear
Hall effect. However, the experimental study of higher-order nonlinear
Hall effect is scarce at present. In this work, we report the observations of the higher odd-order (third-, fifth-, seventh-order) nonlinear
Hall effect in
magnetic topological
insulator Mn(Bi1-xSbx)2Te4 thin flakes. The higher odd-order nonlinear
Hall voltage exhibits a twofold angular dependence and exists only below the Néel temperature. It reaches its maximum near the charge neutral point and decays exponentially as the order of the nonlinear
Hall effect increases. Furthermore, such higher odd-order nonlinear
Hall effect is observed in both odd- and even-layer samples with comparable magnitudes. Theoretical analysis indicates that the higher odd-order nonlinear
Hall effect responses may arise from the Berry
curvature multipoles. Our work paves the way for the study of the higher-order nonlinear transport phenomena.
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All authors Xiubing Li, Zheng Dai, Shuai Zhang, Heng Zhang, Congcong Li, Boyuan Wei, Fengyi Guo, Chunfeng Li, Fucong Fei, Minhao Zhang, Xuefeng Wang, Huaiqiang Wang, Fengqi Song
Materials Science
Room-temperature third-order nonlinear anomalous Hall effect in ferromagnetic metal Fe3GaTe2
Zheng Dai, Shuai Zhang, Jiajun Li et al. (+9 more)
Berry
curvature, as the imaginary component of
quantum geometry, plays a crucial role in condensed matter physics. The spatial distribution of Berry
curvature can be characterized by its dipole and multipole moments, which can induce the nonlinear anomalous
Hall effect (NLAHE). To date, the NLAHE has been demonstrated in various materials, yet reports on room-temperature NLAHE are still limited. In this work, we report the observation of the third-order NLAHE in
ferromagnetic metal Fe3GaTe2. The third-order NLAHE shows hysteretic behavior with the variation of
magnetic field, where the coercive field is the same as that of the anomalous
Hall effect, and the third-order NLAHE remains observable up to the Curie temperature (~350 K). The scaling analysis suggests that the third-order NLAHE may be attributed to the Berry
curvature quadrupole. Our work not only provides an approach to study
magnetic materials through nonlinear electric transports, but also opens up possibilities for the future development of room-temperature third-order nonlinear electronic devices.
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All authors Zheng Dai, Shuai Zhang, Jiajun Li, Xiubing Li, Congcong Li, Fengyi Guo, Heng Zhang, Ziqi Wang, Minhao Zhang, Xuefeng Wang, Huaiqiang Wang, Fengqi Song
Materials Science
Electrically switchable vacancy state revealed by in-operando positron experiments
Ric Fulop, Laurence Lyons IV, Robert Nick et al. (+6 more)
Whether the flash state in electrically driven solids involves non-
equilibrium defect production or is accounted for by Joule heating alone has been debated since 2010. Using positron annihilation spectroscopy on copper, we observe a fully reversible, electrically switchable vacancy population: the DBS S-parameter rises above baseline whenever applied current exceeds a critical density and returns on current removal. Positron lifetime spectroscopy independently confirms open-volume defect formation and reveals a void to cluster relaxation hierarchy. The current-induced vacancy concentration exceeds the thermal-
equilibrium value at 352C by > 106x, is present only while current is applied, and vanishes within minutes. The nucleation rate scales steeply with the applied current, connecting the minute-scale kinetics resolved here to the sub-second flash events observed in ceramic sintering. These results demonstrate current-induced Frenkel-pair production in a metal and identify a defect-mediated, non-
equilibrium contribution to the flash state.
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All authors Ric Fulop, Laurence Lyons IV, Robert Nick, Marc H. Weber, Ming Liu, Haig Atikian, Uwe Bauer, Alexander C. Barbati, Neil Gershenfeld
Disordered Systems and Neural Networks
Unbound States and Mixed Bound–Unbound Phases in Near-Infinitely Deep Potentials
Shujie Cheng, Tong Liu and Gao Xianlong
We investigate the robustness of unbound states in one-dimensional quasiperiodic models with near-infinitely deep potentials. By constructing a deeper extension of the Liu-Xia model and combining inverse participation ratio (IPR) calculations with Lyapunov-exponent analysis based on Avila's global theory, we show that increasing the potential depth does not eliminate unbound states. Instead, it shifts and narrows their energy window to $-2t-V<E<2t-V$. We further extend the analysis to non-Hermitian quasiperiodic potentials with gain and loss. In these systems, unbound states survive within analytically determined real-energy intervals, but they no longer occupy the whole interval uniformly; rather, they coexist with bound states and form a mixed bound-unbound phase. The corresponding boundaries between the mixed region and the pure bound-state regions are obtained exactly from the Lyapunov exponent. These results demonstrate that unbound states in extreme quasiperiodic potentials are controlled not only by the potential depth but also by the spectral and localization structures induced by non-Hermiticity.
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Strongly Correlated Electrons
BCS-BEC crossover of polaritonic condensates in mass-imbalanced semimetal/semiconductor microcavities
Thi-Hau Nguyen, Minh-Tien Tran and Van-Nham Phan
The impacts of the mass imbalance and Coulomb interaction on the complex phase structures of the polaritonic condensates and their Bardeen-Cooper-Schrieffer (BCS)–Bose-Einstein condensation (BEC) crossover in
semiconductor and semimetal microcavities are investigated. In the framework of the unrestricted Hartree-Fock approximation, a two-band electron-hole model involving
photon mode is analyzed by treating Coulomb attraction and light-matter coupling on equal footing. The single-particle spectral functions and the luminescence properties are then examined. In the semiconducting regime, a positive band gap stabilizes tightly bound
excitons and yields predominantly BEC-type excitoniclike polaritonic condensates at low density, while increasing excitation density and reducing mass imbalance drives a continuous crossover toward BCS-type pairing with intermediate and photoniclike polaritonic character. In contrast, the semimetallic regime favors itinerant electron-hole pairing, with BCS-type condensates dominating and BEC excitoniclike coherence emerging only at sufficiently strong Coulomb interaction and large mass imbalance situations. The
evolution of luminescence spectra provides clear spectroscopic signatures of these crossover phenomena, offering a unified framework for understanding and controlling polaritonic condensates in microcavity systems.
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Materials Science
Velocity-field characteristics and device performance in nanoscale amorphous oxide Thin-Film-Transistors
Chankeun Yoon, Xiao Wang, Jatin Vikram Singh et al. (+2 more)
The electron velocity-electric field characteristics in short channel length (50-100 nm) amorphous
oxide field-effect transistors (FETs) are described using measured experimental data from indium gallium zinc
oxide (IGZO) FETs in conjunction with a physics-based model. Such understanding is crucial for the design of FETs for emerging applications such as in back-end-of-line circuitry for advanced
memories and artificial intelligence hardware. In such
semiconductor systems, there is an interplay between trapping and extended state (band) transport that has to be considered in detail for a more complete physical understanding of device operation. The approach described in this paper demonstrates such a method and its use for an exemplary
semiconductor IGZO. It can be used in many emerging thin-film
semiconductors, including several amorphous
oxide semiconductors. The carrier mobility is calculated for dominant scattering mechanisms such as trapped carrier scattering and optical
phonon scattering. The carrier velocity is computed from the mobility using a modified Caughey-Thomas equation. The physical model considers contact resistance, Joule heating, and electric-field-induced carrier heating, all of which are very important in small geometry FETs. The carrier velocity exhibits a tendency to saturate at high electric fields and reaches values > 2*10^6 cm/s when averaged over all induced carriers (both trapped and in the band) and > 4*10^6 cm/s for carriers in the band.
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All authors Chankeun Yoon, Xiao Wang, Jatin Vikram Singh, Sanjay K. Banerjee, Ananth Dodabalapur
Materials Science
Neutron and X-ray Diffraction Reveal the Limits of Long-Range Machine Learning Potentials for Medium-Range Order in Silica Glass
Sai Harshit Balantrapu, Atul C. Thakur, Chris Benmore et al. (+1 more)
Glassy silica is a foundational material in optics and electronics, yet accurately predicting its medium-range order (MRO) remains a major challenge for machine-learning interatomic potentials (MLIPs). While local MLIPs reproduce the short-range SiO4 tetrahedral network well, it remains unclear whether locality alone is sufficient to recover the first sharp diffraction peak (FSDP), the principal experimental signature of MRO. Here, we combine
neutron and X-ray diffraction measurements with large-scale molecular dynamics driven by two MACE-based models: a short-range (SR) potential and a long-range (LR) extension incorporating reciprocal-space gated
attention. The SR model systematically over-structures the network, producing an overly intense FSDP in both the
liquid and glassy states. Incorporating long-range interactions improves agreement with experiment for the
liquid structure by reducing this excess ordering, but the LR model still fails to recover the experimental amorphous MRO after quenching. Ring-statistics and bond-angle analyses reveal that SR model exhibits an artificially narrow distribution dominated by six-membered rings, while the LR model produces a broader but still biased ring population. Despite preserving the correct tetrahedral geometry, both models show limited variability in Si-O-Si angles, indicating constrained network flexibility. These structural signatures demonstrate that both models retain excessive
memory of the parent
liquid network, leading to kinetically trapped and nonphysical medium-range configurations during vitrification. These results show that explicit long-range interactions are necessary but not sufficient for predictive modelling of disordered silica and suggest that accurate MRO further requires training data and sampling strategies that adequately represent the
liquid-to-glass transition.
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All authors Sai Harshit Balantrapu, Atul C. Thakur, Chris Benmore, Ganesh Sivaraman
Quantum Gases
Magnetic-field control of interactions in alkaline-earth Rydberg atoms and applications to XXZ models
Masaya Kunimi and Takafumi Tomita
We study the
magnetic-field dependence of the interactions between two alkaline-earth(-like) Rydberg atoms, ${}^{88}$Sr and ${}^{174}$Yb. Considering the pair of Rydberg states $|ns,{}^3S_1,m_J\rangle$ and $|(n+1)s,{}^3S_1,m_J\rangle$, we show that the effective
Hamiltonian takes the form of an XXZ-type
quantum spin model, as in the alkali-atom case [M. Kunimi and T. Tomita, Phys. Rev. A 112, L051301 (2025)]. We find that the behavior of the anisotropy parameter for ${}^{174}$Yb at zero
magnetic field is significantly different from that for other atomic species. This behavior arises from the interplay of strong
spin-orbit coupling and the resulting multichannel redistribution of Förster defects in ${}^{174}$Yb. We systematically calculate the interaction parameters of the XXZ model in the presence of a
magnetic field and show that they can be tuned by the field. As applications to
quantum many-body problems, we investigate one-dimensional systems in the large-anisotropy regime and show that the folded XXZ model can be realized in ${}^{174}$Yb systems without fine-tuning of the field. We also investigate two-dimensional square-
lattice systems and show that a supersolid phase can emerge in the ground state at the mean-field level.
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Soft Condensed Matter
Linking molecular timescales to linear viscoelastic response in dilute and semidilute unentangled wormlike micelle solutions
Avishek Kumar, Rico F Tabor, P. Sunthar et al. (+1 more)
Unentangled wormlike micelle solutions relax stress through a dynamic interplay of reversible scission and intrachain relaxation involving a hierarchy of molecular timescales whose relationship to linear viscoelastic response remains incompletely resolved. A multiparticle mesoscopic Brownian dynamics framework has been developed in which persistent worms, represented by bead-spring chains with sticky ends, assemble to form wormlike micelles via reversible scission and fusion. Both linear and ring-like micelles are formed across the dilute and semidilute concentration regimes. Accurate predictions of dynamic properties are obtained through inclusion of hydrodynamic interactions using a RPY tensor. We identify and quantify characteristic timescales governing micellar dynamics, including bond lifetimes, self- and non-self-recombination times, breakage times of wormlike micelles of length $L$, relaxation times of various contributions to stress, and the longest relaxation time. The dependence of these timescales on sticker strength, concentration, micellar
topology and hydrodynamic interactions is established. The presence of ring micelles is found to moderately prolong recombination and breakage processes, while hydrodynamic interactions are shown to affect some of the timescales by reducing sticker mobility. When appropriately scaled, the dependence on mean length of the non-self-recombination and micelle breakage times collapse onto master curves. Storage and loss
moduli exhibit distinctive features in the intermediate-frequency regime that are absent in homopolymer solutions. A clear connection is made between micellar timescales and these signatures in the dynamic
moduli at various characteristic frequencies, providing a direct link between microscopic dynamics and macroscopic rheology in unentangled wormlike micellar solutions, in dilute and semidilute concentration regimes.
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All authors Avishek Kumar, Rico F Tabor, P. Sunthar, J. Ravi Prakash
Materials Science · Cross-listed from physics.optics
Nanoscale Fluorescence Thermometry: Probes, Recent Advances and Emerging Directions
Md Shakhawath Hossain, Nhat Minh Nguyen, Thi Ngoc Anh Mai et al. (+10 more)
The transition of materials and devices to nanometer, atomic, and
quantum scales makes thermal characterization increasingly challenging, driving the need for advanced nanoscale thermometry. Fluorescence nanothermometry has emerged as a powerful approach, enabling remote, spatially resolved temperature measurements with sub-micrometer-to-nanometer precision across applications in nanoelectronics, microfluidics, and biological systems. In these systems, temperature is inferred from variations in fluorescence observables, including spectral position, intensity, linewidth, and excited-state dynamics. This review provides a comprehensive and critical overview of fluorescence nanothermometry, covering fundamental mechanisms, material platforms, recent advances, and emerging applications. It further presents a critical evaluation of key challenges and discusses emerging strategies and future research directions toward achieving robust, real-time thermometry. It is anticipated that this review will stimulate further advances in material platforms and system design, accelerating the development of accurate, scalable, and application-ready nanoscale thermometers.
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All authors Md Shakhawath Hossain, Nhat Minh Nguyen, Thi Ngoc Anh Mai, Trung Vuong Doan, Chaohao Chen, Qian Peter Su, Jiayan Liao, Yongliang Chen, Quynh Le-Van, Vu Khac Dat, Toan Dinh, Xiaoxue Xu, Toan Trong Tran
Statistical Mechanics
Percolation Critical Probability of Aperiodic Smith Hat tile(1, $\sqrt3$)
Haitao Gao and Aaryash Bharadwaj
The Smith Hat tile is the first known aperiodic monotile, having been discovered in 2023. The simple structure, constructed using only 8 kites, is unique and well motivated for analysis within percolation theory. The primary goal of this paper is to discover the critical threshold $p_c$ in both site and bond Bernoulli structures using Monte Carlo simulation for the Smith hat tile(1,$\sqrt3$). Our findings are site and bond values of $p_c^s = 0.822725 \pm 0.000044$ and $p_c^b = 0.798161 \pm 0.000044$ for edge percolation and $0.544247 \pm 0.000101$ for site percolation on the dual graph.
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