Materials Science · Cross-listed from quant-ph
Cluster-configurational study of G-center in Silicon
Narayan Pokhrel, Kyungwha Park and Vsevolod Ivanov
Understanding the properties of defects is imperative for proper use for variety of applications including
quantum computing. In this paper, we use the multiconfigurational self consistent field (MCSCF) combined with DFT optimized geometry in order to investigate the
spin and optical properties of G centers in Silicon. By utilizing
quantum chemistry based methods, we show excellent agreement with the Zero
Phonon Line and Zero Field Splitting Tensor components of the G center. We also calculate the theoretical
spin decoherence time of the G centers using Cluster Correlation Expansion (CCE) methods.
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Mesoscale and Nanoscale Physics
Quantum Transport and Apparent Work Function Distributions of Atomic Contacts via a 3D-Printed High-Vacuum Platform
G. Pellicer and C. Sabater
We present a low-cost, 3D-printed high-
vacuum platform integrating a mechanically controllable break-junction system and a custom logarithmic amplifier for room-temperature
quantum transport measurements. Using copper as a highly reactive test case, we successfully resolve the $1G_0$ conductance
quantum under both high
vacuum and anhydrous glycerol, demonstrating the effectiveness of these environments against rapid atmospheric oxidation. In parallel, utilizing gold as a robust
benchmark, we systematically extract the apparent work function ($\phi$) from thousands of tunneling traces across ambient air,
vacuum, and glycerol. Our analysis demonstrates that the statistical distribution of $\phi$ rigorously follows a non-central chi-square distribution. The obtained gold work functions match existing literature across all environments. Although lower than bulk values, they perfectly align with theoretical models accounting for atomic-scale roughness, apex geometry, and environmental adsorbates. Ultimately, this methodology establishes an accessible and reproducible framework for systematic nanoscale research on reactive materials.
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Statistical Mechanics
An exactly solvable macroscopic fluctuation theory of single-file diffusion
Sandeep Jangid, Soumyabrata Saha, Kapil Sharma et al. (+4 more)
Single-file
diffusion is a ubiquitous phenomenon in low-dimensional systems, arising in transport inside narrow channels. Its natural continuum model is a one-dimensional gas of extended Brownian hard rods (BHR). Perhaps owing to the perceived intractability of this problem, much of the literature has traditionally focused on
lattice exclusion models, where integrability methods have yielded remarkable, albeit limited, exact results. A major recent advance comes from a formal solution of macroscopic fluctuation theory (MFT) for the exclusion process. Yet, despite the formal solution, only a handful of properties have been made explicit. We show that the corresponding MFT of the extended BHR gas is in fact exactly solvable through a canonical transformation. We demonstrate this by explicit computation of the large-deviation statistics of the tracer-position and integrated-current in both annealed and quenched ensembles. We further show that an analogous canonical transformation applies to the MFT of
lattice gases with finite-volume exclusion, yielding corresponding tracer and current statistics. We validate our results using rare-event simulations for both the continuum and the
lattice models.
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All authors Sandeep Jangid, Soumyabrata Saha, Kapil Sharma, Jitendra Kethepalli, Benjamin Guiselin, Jacopo De Nardis, Tridib Sadhu
Materials Science
Orbital Hybridization Induces Giant Cubic Rashba Effect at Cu/WO$_{3}$ Interface
Md Aktar Hossain and Saikat Das
Harnessing Rashba
spin-orbit interaction and related spintronic functionalities has traditionally relied on metallic surfaces or interfaces containing elemental heavy metals. Here, using first-principles calculations and Cu(001)/WO$_3$(001) as a model
heterostructure, we show that interfacing a light metal, Cu, with a band
insulator, WO$_3$, yields an interface state that exhibits a robust Rashba
spin splitting arising from the interplay between linear and cubic Rashba effects. The
spin splitting is driven by the strong
spin-orbit coupling of W atoms and enabled by W-Cu orbital hybridization at the interface. The cubic Rashba contribution asymptotically grows with Cu thickness and can be explained in terms of cross-coupling between the
vacuum/Cu and Cu/WO$_3$ interfaces. This interfacial cross-coupling, however, diminishes at larger Cu thicknesses, allowing us to extract the intrinsic cubic Rashba parameter, which has a
giant value of approximately -1.93 eV $\r{A}^3$. In contrast, the linear Rashba parameter is only weakly affected by this cross-coupling and varies from approximately 0.30 to 0.49 eV Å. We further show that sizable linear and cubic Rashba effects persist across several interface geometries and Cu surface orientations, including (110) and (111). Our work identifies the Cu/WO$_3$ interface as a novel light-metal/heavy-element-based
oxide platform for exploring the rich spectrum of Rashba physics, including linear and nonlinear
spin-orbit phenomena.
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Soft Condensed Matter
Gelation of functional peptides by trivalent cations at the air-water interface
Stephen A. Crane, Felipe Jimenez Angeles, Monica Olvera de la Cruz et al. (+2 more)
We report a mechanism for gelation at fluid interfaces driven by multivalent-cation-mediated bridging. At the air-water interface, peptides with bound lanthanide cations undergo a coordination-geometry transition that converts the metal from a single-peptide bound state to a multi-peptide bridging state, driving charge inversion and gel formation. Surface adsorption and non-ideal interfacial electrostatics are implicated in this transition. The gel is stabilized by reversible metal-ligand coordination bonds that resist bulk salt screening, fundamentally distinct from electrostatic charge-inversion gelation in
proteins. This reveals the breakdown of the peptide's coordinating sphere as a distinct pathway for interfacial gelation, independent of the diffuse electrostatic mechanisms governing bulk
protein aggregation.
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All authors Stephen A. Crane, Felipe Jimenez Angeles, Monica Olvera de la Cruz, Ivan J. Dmochowski, Kathleen J. Stebe
Quantum Gases · Cross-listed from gr-qc
Acoustic Firewalls: Analogue Gravity Perspective on the AMPS Paradox
Nikolay S. Akintsov, Artyom P. Nevecheria, Stepan N. Andreev et al. (+1 more)
The monogamy of
quantum entanglement, applied by Almheiri-Marolf-Polchinski-Sully (AMPS) to black holes, obstructs a smooth horizon
vacuum after the Page time. We transcribe this argument to Hawking-like
phonon radiation from a sonic horizon in the Unruh acoustic metric. An exact purity identity shows that post-Page-time unitarity forces the
entanglement between an outgoing
phonon and its interior partner to vanish, selecting a non-Hadamard (Boulware-like)
phonon state, which we define as an acoustic firewall. Its renormalized stress tensor differs from the smooth state by a constant, negative near-horizon flux, and the thermal-atmosphere energy density it removes, measured by a static calorimeter, grows as $(\delta r)^{-2}$ in the radial coordinate toward the horizon (singular in the free-fall frame), cut off at the healing length. The construction is kinematic and does not resolve the information paradox; it yields one concrete, falsifiable prediction: a differential
phonon-calorimetry signal $\mathcal{R}(\delta r)=|\Delta\mathcal{E}|/\mathcal{E}^{(0)}\to(\ell_\kappa/\delta r)^{2}$, present only after the analogue Page time in a Bose-Einstein condensate.
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All authors Nikolay S. Akintsov, Artyom P. Nevecheria, Stepan N. Andreev, Qing-Hua Qin
Soft Condensed Matter · Cross-listed from physics.flu-dyn
Dynamics of a microroller under confinement
Han Gao, Nan Xie, Zaiyi Shen et al. (+3 more)
Rotating particles can translate when placed near a surface, forming microrollers with a wide range of biomedical and microfluidic applications. In this work, we investigate the dynamics of microrollers in confined microchannels with different geometries by combining experiments, numerical simulations, and scaling analysis. In constricted channels, we find that the translational velocity of a microroller decreases as it approaches the constricted region. In both rectangular and cylindrical channels, velocity reversal occurs as the characteristic channel width decreases. Using the force-free condition for free translation, we develop a systematic scaling framework that can be generalized to different channel geometries. The scaling analysis yields functional dependences of the translational velocity on the degree of confinement, which agree well with both experiments and simulations. Importantly, we demonstrate that the viscous stress generated by the far-field rotlet flow governs the observed velocity reduction and reversal, while the translational resistance resulting from the near-field shear flow suppresses translation under tight confinement. The distinct roles of these flow components revealed by our analysis may provide practical guidance for controlling microroller dynamics in confined fluid environments.
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All authors Han Gao, Nan Xie, Zaiyi Shen, Xiaoping Hu, Shiyuan Hu, Ye Xu
Mesoscale and Nanoscale Physics
Electric field controlled spin transport in a topological insulator interfaced with a ferroelectric antiferromagnet
Yogesh Kumar, Pushpendra Gupta, Xinyan Li et al. (+14 more)
Topological
insulators have been explored extensively for
spin-charge interconversion via
magnetic interfaces, yet the true response of their
spin-charge conversion, particularly in the absence of an external
magnetic field, remains to be studied. Here, we report electric-field control of
spin-charge conversion in the topological
insulator Bi$_2$Te$_3$ with the
antiferromagnetic multiferroic BiFeO$_3$, employing a nonlocal
spin transport device. A systematic thickness dependence of the
spin transport across the interface between Bi$_2$Te$_3$ and BiFeO$_3$ reveals a signature of topological surface-state-dominated
spin transport in the
bilayer system. The
spin-charge conversion remains robust for thicknesses above 10 nm but falls rapidly with reducing thickness and vanishes at 5 nm. This is consistent with the hybridization-induced emergence of a trivial insulating phase, which is supported by the coherency factor estimated from the magnetoconductance of Bi$_2$Te$_3$. These results establish that
spin-momentum-locked surface states dominate interfacial
spin transport in the decoupled regime. Beyond presenting efficient
spin-charge interconversion at an entirely insulating
magnetic interface, this work also highlights sputter-deposited Bi$_2$Te$_3$ as a high-quality and scalable platform for integrating
quantum materials into devices. The nonlocal
spin transport approach presented here provides a simple and direct evidence of
spin-charge conversion and opens an efficient and practical pathway toward designing energy-efficient
spin-based devices.
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All authors Yogesh Kumar, Pushpendra Gupta, Xinyan Li, Richa Mudgal, Ashish Omar, Ryan Chen, Mito Funatsu, Maya Ramesh, Nicholas Reiterer, Yuanqi Lyu, Yiping Zeng, Darrell G. Schlom, Alessandra Lanzara, Robert J. Birgeneau, James G. Analytis, Ramamoorthy Ramesh, Sajid Husain
Strongly Correlated Electrons
Terahertz Lattice Imprint of a Hidden Multipolar Ordering Transition in Gd$_2$Ru$_2$O$_7$
Nicolas M. Kawahala, Rafael L. Sabainsk, Esteban Marulanda et al. (+2 more)
Magnetic order carried by higher-rank multipoles produces no net moment and couples only weakly to conventional dipolar probes. Recently, the
lattice has been proposed as an alternative detection channel for the associated ordering transitions. Here we report magneto-terahertz time-domain spectroscopy of the pyrochlore ruthenate Gd$_2$Ru$_2$O$_7$, in which a single spectrum resolves an exchange-split Gd$^{3+}$ transition and an infrared-active optical
phonon. The temperature and field dependence of the
magnetic mode give two independent determinations of the internal exchange field at the rare-earth site, which yield a magnitude of 5-6 T and a free-ion $g$-factor. The optical
phonon, sensitive to
spin-disorder scattering rather than to the static exchange field, exhibits a sharp anomaly in frequency and lifetime at 10 K that shifts to 30 K under 7 T, which we identify as an ordering transition of the Gd sublattice hidden from bulk thermodynamic probes. These results identify
spin-
phonon coupling as a route to rare-earth ordering transitions in multipolar magnets, one that is applicable to polycrystalline samples.
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All authors Nicolas M. Kawahala, Rafael L. Sabainsk, Esteban Marulanda, Rafael S. Freitas, Felix G. G. Hernandez
Materials Science
The WEST code for large-scale excited-state materials simulations
Victor Wen-zhe Yu, Siyuan Chen, Yu Jin et al. (+5 more)
We present WEST, an open-source plane-wave pseudopotential code for large-scale excited-state materials simulations, and describe its theoretical foundations, software architecture, and capabilities. WEST implements full-frequency GW,
quantum defect
embedding theory, the Bethe-Salpeter equation, and time-dependent density functional theory within a common algorithmic framework that avoids the explicit computation of virtual electronic states. By combining density functional and density
matrix perturbation theory, low-rank representations of the dielectric screening and exact exchange, and localization techniques, WEST achieves favorable computational scaling with system size. The code supports the calculation of quasi-particle and neutral excitation energies, optical and photoluminescence spectra, excited-state forces, and non-adiabatic couplings, with interoperable workflows connecting to
quantum chemistry, vibronic coupling, and
quantum computing packages. A hierarchical parallelization strategy and GPU acceleration deliver near-ideal strong scaling to thousands of GPUs, enabling accurate excited-state simulations of systems with more than a thousand atoms. Representative applications, spanning the full optical cycle of solid-state
spin defects, self-trapped
excitons in metal-halide perovskites, and the optical response of
liquid water and ice, demonstrate the accuracy and versatility of the code across diverse material classes. The capabilities implemented in WEST establish the code as a scalable platform for predictive excited-state simulations, high-throughput materials discovery, and the generation of high-fidelity
datasets for machine learning in computational materials science.
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All authors Victor Wen-zhe Yu, Siyuan Chen, Yu Jin, Vrindaa Somjit, Stefano Paolo Villani, Jiawei Zhan, Marco Govoni, Giulia Galli
Statistical Mechanics · Cross-listed from hep-th
Temporal Entanglement from Twist Correlators in 2d Conformal Field Theory and Holography
Alice Bernamonti, Federico Galli, Michal P. Heller et al. (+2 more)
We formulate timelike
entanglement entropy and its Rényi extension in two-dimensional conformal field theory through the analytic continuation of replica twist correlators to time-ordered, timelike-separated insertions. This field-theoretic construction grounds and generalizes recent developments, and applies to temporal subregions of arbitrary extent. Within three-dimensional holography, the semiclassical boundary correlator identifies boundary-anchored complex geodesics as the relevant bulk saddles and selects the one with the smallest real part of the length. This provides a direct boundary derivation of the proposed complex extremal surface prescription and extends to Rényi index $n>1$, for which we explicitly construct the corresponding complex
cosmic brane geometry in the
vacuum. We develop these ideas in several representative settings, including locally and globally excited states and
quantum operator quenches, making manifest the precise agreement between boundary twist correlator and bulk complex geodesic calculations. For AdS-Vaidya, our approach predicts a different result from earlier piecewise geodesic constructions, while reproducing the field theory answer. Across these examples, the operator ordering uniquely determines the imaginary part of the complex-valued
entropy, which is quantized in units of $c\pi/6$ and sensitive to the effective causal structure but not to the underlying dynamics.
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All authors Alice Bernamonti, Federico Galli, Michal P. Heller, Fabio Ori, Alexandre Serantes
Strongly Correlated Electrons
Thermodynamic and electrical transport properties of the half-Heusler plumbide TbAuPb
Abhinav Agarwal, Snehashish Chatterjee, Maciej J. Winiarski et al. (+4 more)
Structural, thermodynamic and electrical transport properties of TbAuPb were investigated on single
crystals. The compound was found to crystallize with the cubic MgAgAs-type structure characteristic of half-Heusler materials. It orders antiferromagnetically at TN = 5 K and undergoes a transition into a different
antiferromagnetic phase emerging in high
magnetic fields. Electrical transport in TbAuPb exhibits a multiband character, with a predominance of hole-like carriers. Angular magnetoresistance evolves systematically with applied
magnetic field and changes its
symmetry near the
spin-reorientation transition, highlighting strong coupling between the charge transport and the
magnetic order. The results of first-principles calculations indicate that TbAuPb is a band inverted semimetal in the non-
magnetic state, which becomes topologically trivial in the field-induced
ferromagnetic state.
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All authors Abhinav Agarwal, Snehashish Chatterjee, Maciej J. Winiarski, Orest Pavlosiuk, Dorota A. Kowalska, Piotr Wisniewski, Dariusz Kaczorowski
Disordered Systems and Neural Networks · Cross-listed from q-bio.NC
Activity Regeneration from Silent States in Neuronal Networks with Transient Synaptic Memory
Mozhgan Khanjanianpak and Alireza Valiadeh
Transient synaptic
memory has emerged as a potential mechanism for maintaining short-term information even in the absence of persistent neuronal activity. However, it remains unclear whether the hidden synaptic state alone contains sufficient information to predict the future
evolution of neuronal networks after activity has ceased. Here, we introduce a minimal neuronal network model with finite-lifetime synapses and investigate the mechanism underlying spontaneous activity regeneration following complete neuronal silence. We show that the residual synaptic configuration at the first silent state already determines whether network activity terminates after a single activation cycle or spontaneously regenerates an additional cycle. By analyzing this synaptic-
memory snapshot, we identify the Latent Excitatory Recruitment (LER) capacity, quantified by the cumulative number of fresh excitatory
neurons, as a near-perfect predictor of multi-cycle dynamics without continuing the subsequent network simulation. Remarkably, these distinct dynamical outcomes emerge in an otherwise homogeneous neuronal network, demonstrating that transient synaptic
memory alone is sufficient to generate diverse future dynamics. Our findings provide a mechanistic explanation for activity regeneration from a residual synaptic state and suggest that short-term
memory is encoded not only in ongoing neuronal activity but also in the latent synaptic configuration that preserves the network's capacity to recruit new neuronal assemblies. More broadly, the proposed snapshot-based framework offers a new perspective for predicting and potentially controlling the future
evolution of neuronal networks.
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Soft Condensed Matter
Driven Odd Elasticity in Passive Mechanical Metamaterials
Mohamad Rahimi and Harold S Park
We present a mechanical mechanism leveraging passive mechanical components, i.e.
chiral gears and a square
lattice metamaterial, to demonstrate driven odd elasticity in a mechanical metamaterial. The mechanism couples tension and shear in a non-reciprocal way, resulting in an odd shear modulus. The emergence of this odd shear modulus enables non-conservative work in a standard quasistatic strain cycle, and further enables the non-Hermitian skin effect in dynamics. Our results demonstrate that odd elasticity can be achieved in mechanical structures using passive elements without electronic components coupled with feedback or robotic control systems.
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Strongly Correlated Electrons
$\texttt{iNORG}$: An open-source quantum impurity solver package based on the natural orbitals renormalization group
Jia-Ming Wang, Yi-Heng Tian, Yin Chen et al. (+3 more)
In the context of dynamical mean-field theory (DMFT) calculations for strongly correlated electron systems,
quantum impurity solvers play a central computational role in treating correlated
lattice models and realistic materials. Consequently, developing efficient and robust
quantum impurity solvers remains a key challenge. In this paper, we present an open-source
quantum impurity solver package based on the natural orbitals renormalization group (NORG) method, dubbed $\texttt{iNORG}$. This software delivers high accuracy with reduced computational cost by optimizing the bath representation using natural orbitals and incorporating advanced features such as efficient
Hilbert space selection and efficient
algorithms for computing Green's functions. We first introduce the basic principle of the NORG method and then discuss the implementation details. The software framework, major features, and installation procedure for $\texttt{iNORG}$ are explained as well. Finally, several simple examples are presented to demonstrate the usage of $\texttt{iNORG}$.
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All authors Jia-Ming Wang, Yi-Heng Tian, Yin Chen, Ru Zheng, Rong-Qiang He, Zhong-Yi Lu
Materials Science · Cross-listed from physics.optics
Magneto-optical hologram lens with microsecond focal switching in magnetic garnet
Hibiki Miyashita, Toshiaki Watanabe, Eri Negishi et al. (+3 more)
Active lenses based on metasurfaces have been demonstrated across broad applications, and their response speeds remain limited to the microsecond range. Here we report the experimental demonstration of a magneto-optical (MO) active lens based on a
magnetic hologram formed on a
magnetic garnet film. A Fresnel zone plate pattern was created using an array of permanent magnets, focusing a 633 nm
laser beam of 12.5 mm diameter to a spot size of 0.7 mm at a focal length of 3.1 m with a modulation depth of ~91%. The focusing state was reversibly switched by applying an external
magnetic field pulse. Through optimization of the
magnetic field application system, a switching speed of 10.8 $\mu$s was achieved, surpassing the operating speeds of conventional active lenses. The intrinsic picosecond-scale response of the MO effect indicates that further improvement in switching speed is achievable, establishing this work as a proof-of-concept for ultra-fast active lenses.
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All authors Hibiki Miyashita, Toshiaki Watanabe, Eri Negishi, Mitsuteru Inoue, Kazushi Ishiyama, Taichi Goto
Quantum Gases
Dipolar mixtures in checker-board optical bilayers
Rukmani Bai and Luis Santos
Ultra-cold dipolar mixtures in component-dependent optical potentials constitute an interesting platform for the study of the interplay between intra- and inter-component anisotropic long-range interactions. We study the particular case of binary dipolar mixtures placed in separated
bilayers which are displaced in an anti-magic wavelength configuration. Using a combination of second-order perturbation theory and cluster-Gutzwiller calculations, we unveil a rich landscape of possible crystalline phases for the two components, showing that, interestingly, inter-site hopping may result, via super-exchange, in solid-into-solid transitions between different crystalline phases. These crystalline phases and the corresponding transitions can be experimentally realized using e.g. lanthanide mixtures in optical
lattices.
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Materials Science
Using superpixels for interpretable feature reduction in large 2D diffraction datasets
Andreas Werbrouck, Nikhila C. Paranamana, Andrew C. Meng et al. (+2 more)
Large 2D diffraction
datasets, consisting of hundreds or thousands of measurements, are commonly acquired with 4D-STEM electron diffraction or at synchrotron X-ray beamlines. Machine learning and artificial intelligence offer great promise for analyzing these
datasets. However, the sheer volume of data presents a significant data processing bottleneck. Cropping the detector and pixel binning are standard ways to reduce data size. Here we propose grouping and averaging pixels into superpixels of variable area. High-information regions are sampled densely, while low-information areas are collected into larger superpixels. In the process,
symmetries in the data are captured and exploited, making this approach suitable for preprocessing 2D diffraction data. We compare two variance-minimizing methods: K-means clustering (top-down) and agglomerative clustering (bottom-up) and demonstrate superior scaling and interpretability for the bottom-up method. As these methods are distance-based, we demonstrate that the construction of superpixels can be accelerated using Gaussian random projection. Finally we show over 100-fold acceleration for phase mapping with Non-negative
matrix factorization on a 4D-STEM
dataset when superpixels are used as a preprocessing step.
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All authors Andreas Werbrouck, Nikhila C. Paranamana, Andrew C. Meng, Xiaoqing He, Matthias J. Young
Soft Condensed Matter · Cross-listed from physics.bio-ph
Confinement effects on protein stability in a freezing water environment
Yanis R. Espinosa, H. Ariel Alvarez and C. Manuel Carlevaro
Understanding how
proteins behave at low temperatures remains a central challenge in biophysics, with direct implications for cold denaturation and cryopreservation. While cold denaturation of
proteins in the supercooled
liquid regime has been studied extensively, the behavior of a
protein embedded in a growing ice
lattice remains largely inaccessible to experiments. Here we use molecular dynamics simulations that explicitly capture ice Ih formation to characterize the conformational dynamics of yeast frataxin (Yfh1) as its aqueous environment crystallizes. Using four independent ice-seeded replicas and
liquid-water controls at three temperatures, we first validate the
liquid-solid transition through convergent changes in solvent density, potential energy, and local bond-order parameters (W4, W6). Principal component analysis (PCA), dihedral PCA (dPCA), and free-energy landscapes then reveal that crystallization of the solvent markedly reshapes the accessible conformational space, shifting it from a continuous, highly connected regime in
liquid water toward a discretized landscape dominated by confined states. Complementary analyses of solvent-accessible surface area (SASA), radius of gyration, and hydrogen bonding indicate a solvent-driven reorganization of
protein-water interactions: although first-shell water remains
liquid-like, its surface density increases under freezing, while conformational sampling contracts. Together, these results indicate that
protein behavior at low temperatures is governed not by temperature alone but by the structural organization of the surrounding water. By imposing geometrical constraints on the solvent, ice formation restricts conformational sampling while preserving – and even densifying – the interfacial hydration layer, highlighting the role of water structure as a determinant of
protein stability under freezing conditions.
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Materials Science
Dolomite Mineral-Inspired Equilateral Triangular-Lattice Magnets for Quantum Magnetism
Yang Zhao, Zhaoyi Li, Zhibin Qiu et al. (+3 more)
Equilateral triangular
lattice magnets provide a versatile materials platform for exploring exotic
quantum spin phenomena, while their field-tunable
magnetic entropy offers opportunities for low-temperature adiabatic demagnetization refrigeration. Inspired by the natural mineral, we proposed a chemical strategy to achieve equilateral TL magnets, leveraging the high
crystal symmetry of a large family of dolomite-type materials. As typical examples, the dolomite-type materials SnM(BO3)2 (M = Co, Mn) were synthesized, and structural analysis reveals that Co2+ and Mn2+ ions form equilateral triangular
lattices with an A-B-C stacking fashion. The
magnetic susceptibilities and specific heat measurements reveal dominant
antiferromagnetic interactions, with Neel temperatures of 0.49K for SnCo(BO3)2 and 0.96K for SnMn(BO3)2, respectively. Our results establish the dolomite-type M'M(X)2 (M'and M sites allow various valence states, e.g., +4/+2 or +3/+3; X = CO32- or BO33-) system as a chemically flexible and structurally perfect material platform for exploring frustrated magnetism and low-temperature magnetocaloric applications.
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All authors Yang Zhao, Zhaoyi Li, Zhibin Qiu, Jianqiao Wang, Bo Wen, Shu Guo
Strongly Correlated Electrons
Lecture Notes: The two-dimensional electron Wigner crystal – What's old and what's new?
Brian Skinner
These are lecture notes created for a short lecture series at the 2026 CTEQ Summer School at Penn State. They are written in a conversational and informal style. The goal of these notes is to introduce and review a smattering of old and new ideas about the Wigner
crystal (the solid phase of the two-dimensional electron system) in the context of recent experiments. Particular emphasis is given to the semiclassical description of the Wigner
crystal, its
quantum melting transition, its
spin order, and the ways in which the Wigner
crystal can be modified by Berry
curvature.
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Strongly Correlated Electrons
Angular momentum splitter effect of $d$-wave axial phonons in orbital altermagnets
Dimos Chatzichrysafis and Alexander Mook
We theoretically demonstrate that axial
phonons,
lattice vibration quanta carrying finite angular momentum, can host a $d$-wave angular momentum texture in orbital altermagnets in the absence of
spin-orbit coupling. We consider a minimal electronic tight-binding model with $d$-wave loop-current order that breaks time-reversal
symmetry. Within the Born-Oppenheimer approximation, we incorporate electron-
phonon coupling via the molecular Berry
curvature and show that the underlying $d$-wave orbital
magnetic moment texture of the electronic state is transferred to the
phonons without requiring the relativistic
spin-orbit coupling. Our results expand the range of platforms available for engineering axial
phonons and point to functionality unique to $d$-wave textures, including angular-momentum Seebeck and splitter effects, corresponding to longitudinal and transverse angular-momentum currents driven by a temperature gradient.
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Statistical Mechanics
Modified Family-Vicsek Scaling and Probability Distributions for Brownian Castle Interfaces
Noah Sublett, Charles Sutton, Benjamin Long et al. (+1 more)
The Brownian Castle is a new interface growth model that is a variation on the well-known ballistic deposition model that results in an entirely new universality class. We present numerical verification that the interface width for BC interfaces displays modified Family-Vicsek scaling properties up to finite size corrections. Specifically, we find a growth exponent of $\beta=0.470 \pm 0.012$ and a roughness exponent of $\alpha=1.01 \pm 0.018$. The scaling is modified at short times with a size scaling exponent that described the early time dependence of interface width on length. The probability distribution of heights for the BC interface shows significant deviations from simple Gaussian behavior and the probability distribution of height changes shows a Cauchy-Lorentz form consistent with expectations for a process involving relatively large jumps.
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All authors Noah Sublett, Charles Sutton, Benjamin Long, Daniel B. Dougherty
Materials Science
Chemical short-range order controls deformation pathways in a complex concentrated alloy
Angelo F. Andreoli, Gabriela B. Ribeiro, Guilherme C. Stumpf et al. (+12 more)
Chemical short-range order (CSRO) is an intrinsic feature of complex concentrated
alloys (CCAs), yet its influence on deformation mechanisms is controversial because of the inconclusive state of concurrent CSRO quantification during deformation. Here, we provide experimental evidence that CSRO acts as an intrinsic thermodynamic state variable governing stacking-fault energetics and deformation pathways in a Co30Cr40Ni30
alloy. By comparing quenched (CSRO-lean) and aged (CSRO-enriched) conditions with equivalent grain structure and phase constitution, we isolate the influence of atomic-scale chemical ordering on mechanical behavior. Calorimetry confirms reversible CSRO formation, while synchrotron X-ray diffraction and electron microscopy reveal that CSRO suppresses deformation-induced fcc-hcp martensitic transformation at both room and cryogenic temperatures. Despite differences in transformation dynamics, the macroscopic tensile response is still broadly similar. Atomistic simulations show that CSRO increases both stable and unstable stacking-fault energies, raising the energetic barrier for partial-dislocation activity and stabilizing the fcc
lattice against transformation. Together, the experimental and computational results establish CSRO as an added degree of freedom for tuning stacking-fault energetics and controlling deformation pathways in complex concentrated
alloys.
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All authors Angelo F. Andreoli, Gabriela B. Ribeiro, Guilherme C. Stumpf, Maria F. L. Valverde, Gustavo Bertoli, Vinícius P. Bacurau, David D. S. Silva, Pedro H. F. Oliveira, Eric M. Mazzer, Mamta Silwal, Garritt J. Tucker, Rodrigo Freitas, Martin Sahlberg, Daniel Miracle, Francisco G. Coury
Materials Science
Revealing the MoS2 Growth Mechanism in Chemical Vapor Deposition: Real-Time Imaging and Statistical Analysis
Faizal Arifurrahman, Tianshu Zhai, Yuguo Wang et al. (+4 more)
Chemical Vapor Deposition (CVD) is a promising method for scalable synthesis of two-dimensional transitional metal dichalcogenides (TMDs) such as MoS2, but challenges in reproducibility and controllability persist due to an incomplete understanding of their dynamic growth mechanisms. While in-situ characterization methods could provide valuable insights, it remains challenging to track a large ensemble of
crystals to enable quantitative, statistical analysis. Here, we address this gap by developing and applying a semi-automated image processing pipeline to analyze in-situ optical microscopy footage of MoS2 growth. This framework enables the high-throughput reconstruction of complete growth trajectories for over 400 individual
crystals from a single experiment. Our statistical analysis demonstrates that MoS2 crystallization is governed by an edge-attachment-limited mechanism rather than by precursor
diffusion. Furthermore, MoS2
crystals exhibit non-competitive growth, indicating that precursor supply does not limit the growth of neighboring flakes until physical impingement occurs. These findings provide direct, quantitative evidence that advances the fundamental understanding of TMD growth, establishing a powerful methodology for rational optimization of the CVD growth of two-dimensional materials.
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All authors Faizal Arifurrahman, Tianshu Zhai, Yuguo Wang, Jing Zhang, Andrew L. Hitt, Jun Lou, Ming Tang
Mesoscale and Nanoscale Physics
Realization and manipulation of spiral charge density waves in a two-dimensional metal
Lili Zhou, Ruizi Zhang, Chen Si et al. (+14 more)
Nearly degenerate charge-density-wave (CDW) states play a central role in the competition among collective phenomena. In real materials, however, these states are often intertwined by disorder, hindering their disentanglement and control. Here we show that strain can lift this near-degeneracy and spatially separate distinct CDW states in NbSe2. Using van der Waals (vdW) interactions, we stabilize a micron-scale strain network that produces spatially inhomogeneous strain fields. Within this landscape, the intrinsic 3 * 3 CDW superlattice of pristine NbSe2 transforms into an isolated unidirectional 4 * 1 order under 1D-confined compression, and into a 2 * 2 order under biaxial tension. The 4 * 1 CDW has a multiband origin and exhibits markedly enhanced thermal stability, persisting up to 70 K. At strain-network nodes, it further develops into
chiral spiral textures, which can be melted by voltage pulses. These results establish strain as a powerful approach to disentangle, stabilize and manipulate competing electronic orders.
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All authors Lili Zhou, Ruizi Zhang, Chen Si, Zhaoteng Dong, Mengya Ren, Keru Guo, Can Zhang, Jizheng Wu, Fudi Zhou, Huixia Yang, Yaxin Zhao, Guoyuan Yang, Xiaolong Xu, Yuanxiao Ma, Xiao Kong, Yu Zhang, Yeliang Wang
Superconductivity
Superconducting proximity effect in a strongly correlated charge-transfer insulator
Mengya Ren, Yaoyao Chen, Fudi Zhou et al. (+9 more)
Proximity-induced superconductivity in strongly correlated
insulators provides a versatile route for engineering
quantum states of matter and artificial systems with tailored functionalities. However, microscopic interplay between superconductivity and correlated insulating states remains poorly understood. Here we use ultralow-temperature scanning tunnelling microscopy (STM) to systemically investigate superconducting proximity effects in a charge-transfer
insulator. Via STM tip manipulation, atomically sharp lateral junctions composed of superconducting monolayer H-NbSe2 and charge-transfer insulating monolayer T-NbSe2 are constructed, enabling direct access to tunable coupling regimes. In the weak-coupling regime, there is a robust proximity-induced superconducting gap in T-NbSe2, with a reduced gap value relative to that of H-NbSe2. Upon entering the strong-coupling regime, T-NbSe2 exhibits a superconducting gap comparable to that of H-NbSe2, accompanied by pronounced particle-hole-symmetric in-gap bound states, consistent with Yu-Shiba-Rusinov-like excitations. These findings establish monolayer H/T-NbSe2 lateral junctions as a model platform for elucidating superconducting proximity effects in strongly correlated charge-transfer
insulators.
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All authors Mengya Ren, Yaoyao Chen, Fudi Zhou, Can Zhang, Zhaoteng Dong, Lili Zhou, Quanzhen Zhang, Huixia Yang, Xiaolong Xu, Yuanxiao Ma, Yu Zhang, Yeliang Wang
Mesoscale and Nanoscale Physics
Phonon down-conversion by normal metals for superconducting devices
Guglielmo La Magna and Gianluigi Catelani
Thanks to low dissipation, superconducting devices are promising for a number of applications, such as detectors and implementations of
quantum computation. However, their working can be adversely impacted by quasiparticles, which is why so-called quasiparticle poisoning mechanisms and their mitigation are under intense investigation. Here we focus on one poisoning mechanism, namely pair-breaking
phonons, and its mitigation through down-conversion by a normal-metal film - the process in which scattering of high-energy
phonons by electrons lowers the energy of the former below the pair-breaking threshold. To study the down-conversion, we introduce a model based on kinetic equations, which we solve both analytically (approximately) and numerically in the steady state. We use the solution the estimate a properly-defined down-conversion efficiency which depends on material parameters (such as the strength of electron-
phonon interaction and the
phonon transmission coefficient at interfaces) and film and substrate thicknesses. Interestingly, we find that the efficiency is nearly optimal over a finite range of metal thicknesses, with the minimum near-optimal thickness being typically of the order of a micron.
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Materials Science
Ultrafast altermagnetophononics
Chenyu Wang, Yaxian Wang and Sheng Meng
Altermagnets feature
symmetry-dictated nontrivial
spin splitting in electronic structure promising for next-generation spintronics, yet their ultrafast dynamical manipulation remains largely unexplored. Here, we establish altermagnetophononics as an efficient route for
magnetic control via selective
symmetry breaking induced by coherent
phonons. Using the prototypical altermagnet $\alpha$-MnTe as an example, we demonstrate that the targeted excitation of B$_{1g}$ mode selectively lifts the
symmetry constraints protecting altermagnetism (AM), driving ultrafast transition into a transient compensated ferrimagnetic (cFiM) phase characterized by a global
spin splitting without net magnetization. Further, we show that the proposed mechanism is broadly applicable by demonstrating a multi-mode
symmetry breaking pathway, and by realizing a ferrimagnetic order with reversible
magnetic moment in metallic CrSb. These findings elucidate the potential to obtain desirable nonequilibrium properties in altermagnets via coherent phononic control over their
spin splittings.
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Statistical Mechanics · Cross-listed from physics.flu-dyn
Condition for $1/f$ noise to occur along with an example for a diffusion equation
H. Mouri
While $1/f$ noise is ubiquitous and has been found in various systems, its physics remains uncertain. From an analytical study of an ordinary
diffusion equation, we find an additional example of the $1/f$ noise. The formula for this example, together with existing knowledge about scaling in fluid
turbulence, implies a necessary and sufficient condition for the occurrence of any stationary $1/f$ noise. That is, the noise needs to be characterized by two constant frequencies of $f_{\rm low} \ll f_{\rm high}$. For a frequency range from $f = f_{\rm low}$ to $f_{\rm high}$, it is further needed that, except for the mean amplitude of the noise, there is no other constant parameter. Then, at $f_{\rm low} \ll f \ll f_{\rm high}$, the noise scales asymptotically as $1/f$. Being statistical and simple, our condition applies to any system and hence explains the ubiquity of the $1/f$ noise. It is also applicable to some systems with noise of $\alpha \ne 1.0$ for $1/f^{\alpha}$, via intermittency analogous to that of the
turbulence.
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