CMP Journal 2026-01-12
Statistics
Nature Materials: 2
Nature Reviews Physics: 1
Physical Review Letters: 6
arXiv: 66
Nature Materials
Experimental observation of liquid-solid transition of nanoconfined water at ambient temperature
Original Paper | Characterization and analytical techniques | 2026-01-11 19:00 EST
Wentian Zheng, Shichen Zhang, Jian Jiang, Yipeng He, Rainer Stöhr, Andrej Denisenko, Jörg Wrachtrup, Xiao Cheng Zeng, Ke Bian, En-Ge Wang, Ying Jiang
Nanoconfined water exhibits many abnormal properties compared with bulk water. However, the origin of those anomalies remains controversial due to the lack of experimental access to the molecular-level details of the hydrogen-bonding network of water within a nanocavity. Here we address this issue by combining scanning probe microscopy with nitrogen-vacancy-centre-based quantum sensing. Such a technique allows us to characterize both dynamics and structure of water confined between a hexagonal boron nitride flake and a hydrophilic diamond surface by nanoscale nuclear magnetic resonance. We observe a liquid-solid phase transition of nanoconfined water at ambient temperature with an onset confinement size of ~1.6 nm, below which the water diffusion is considerably suppressed and the hydrogen-bonding network of water becomes structurally ordered. The complete crystallization is observed below a confinement size of ~1 nm. The liquid-solid transition is further confirmed by molecular dynamics simulation. These findings shed new light on the phase transition of nanoconfined water and may form a unified picture for understanding water anomalies at the nanoscale.
Characterization and analytical techniques, Chemical physics, Nanoscale materials, Phase transitions and critical phenomena
Wafer-scale monolayer dielectric integration on atomically thin semiconductors
Original Paper | Electronic devices | 2026-01-11 19:00 EST
Zhenzhen Shen, Haoqi Wu, Chunsen Liu, Zizheng Liu, Yongbo Jiang, Tanjun Wang, Peng Zhou
A promising strategy for further miniaturizing metal-oxide-semiconductor field-effect transistors is the use of ultrathin two-dimensional channel materials. However, achieving robust dielectric integration with a sub-1-nm capacitance equivalent thickness (CET) remains challenging. Here we present a wafer-scale monolayer MoO3, transformed from MoS2, which can be seamlessly integrated with atomically thin semiconductors. Its atomically flat surface and the strong electronegativity of Mo6+ further enable the uniform deposition of high-κ dielectrics. Utilizing the 0.96-nm-CET MoO3/HfO2 as the dielectric, the top-gated p-type (n-type) two-dimensional transistors show a high ON/OFF ratio of 6.5 × 106 (3.2 × 108) and a steep subthreshold swing of 60.8 (63.1) mV dec-1. Statistical analysis of a 1,024-device array achieves a high yield of 92.2%. Furthermore, when monolayer MoO3 is used as the top-gated dielectric with an ultimately scaled CET of 0.64 nm, the gate leakage current meets the low-power limit standard (1.5 × 10-2 A cm-2) over the entire bias range. Our study provides a scalable approach for the integration of ultralow-CET dielectrics on two-dimensional materials, marking a critical step towards their future industrial deployment.
Electronic devices
Nature Reviews Physics
The Yang-Mills Millennium problem
Review Paper | Pure mathematics | 2026-01-11 19:00 EST
Michael R. Douglas
The Yang-Mills Millennium Prize problem is one of the great challenges of mathematical physics. In the quarter century since it was set, what progress has been made? This Review outlines the problem from a physics point of view, gives its physical background, explains its nature and significance as a problem in mathematics and surveys promising approaches from recent years.
Pure mathematics, Theoretical particle physics
Physical Review Letters
Double-Bracket Quantum Algorithms for Quantum Imaginary-Time Evolution
Article | Quantum Information, Science, and Technology | 2026-01-12 05:00 EST
Marek Gluza, Jeongrak Son, Bi Hong Tiang, René Zander, Raphael Seidel, Yudai Suzuki, Zoë Holmes, and Nelly H. Y. Ng
Efficiently preparing approximate ground states of large, strongly correlated systems on quantum hardware is challenging, and yet, nature is innately adept at this. This has motivated the study of thermodynamically inspired approaches to ground-state preparation that aim to replicate cooling process…
Phys. Rev. Lett. 136, 020601 (2026)
Quantum Information, Science, and Technology
Experimental Phase-Matching Quantum Cryptographic Conferencing in Symmetric and Asymmetric Fiber Channels
Article | Quantum Information, Science, and Technology | 2026-01-12 05:00 EST
Mi Zou, Bin-Chen Li, Shuai Zhao, Yingqiu Mao, Dandan Qin, Xiao Jiang, Teng-Yun Chen, and Jian-Wei Pan
Phase-matching quantum cryptographic conferencing can operate over realistic intercity fiber networks, advancing the feasibility of multiparty quantum communication.
Phys. Rev. Lett. 136, 020801 (2026)
Quantum Information, Science, and Technology
Monte Carlo Simulations of Crystal Defects in Open Ensembles
Article | Condensed Matter and Materials | 2026-01-12 05:00 EST
Flynn Walsh, Babak Sadigh, Joseph T. McKeown, and Timofey Frolov
A Monte Carlo approach for open ensembles allows the simulation of variable number of defects in materials.
Phys. Rev. Lett. 136, 026201 (2026)
Condensed Matter and Materials
Foundations of the Ionization Potential Condition for Localized Electron Removal in Density Functional Theory
Article | Condensed Matter and Materials | 2026-01-12 05:00 EST
Guy Ohad, María Camarasa-Gómez, Jeffrey B. Neaton, Ashwin Ramasubramaniam, Tim Gould, and Leeor Kronik
Optimal tuning of functional parameters in density functional theory approximations, based on enforcing the ionization potential theorem, is a method of choice for the nonempirical prediction of the electronic structure of finite systems. This method has recently been extended to the bulk limit, bas…
Phys. Rev. Lett. 136, 026401 (2026)
Condensed Matter and Materials
Altermagnet-Driven Magnon Spin Splitting Nernst Effect
Article | Condensed Matter and Materials | 2026-01-12 05:00 EST
Yuben Yang, Di Wang, Bin Yang, Peng Wang, Yuxuan Mu, Yuanzhe Tian, Bowen Zheng, Weijie Qin, Kaiyuan Wang, Biying Huang, Baigeng Wang, Xiangang Wan, and Di Wu
Magnonic spin current generation in antiferromagnets has emerged as an important topic in spintronics, where a strong external magnetic field or a Dzyaloshinskii-Moriya interaction (DMI) is generally required. Recently, a type of antiferromagnets characterized by momentum-dependent nonrelativistic s…
Phys. Rev. Lett. 136, 026701 (2026)
Condensed Matter and Materials
Inferring Charge-Noise Source Locations from Correlations in Spin Qubits
Article | Condensed Matter and Materials | 2026-01-12 05:00 EST
J. S. Rojas-Arias, A. Noiri, J. Yoneda, P. Stano, T. Nakajima, K. Takeda, T. Kobayashi, G. Scappucci, S. Tarucha, and D. Loss
We investigate low-frequency noise in a spin-qubit device made in isotopically purified Si/Si-Ge. Observing sizable cross-correlations among energy fluctuations of different qubits, we conclude that these fluctuations are dominated by charge noise. At low frequencies, the noise spectra are not well …
Phys. Rev. Lett. 136, 027001 (2026)
Condensed Matter and Materials
arXiv
Giant and Oscillatory Junction Magnetoresistance via RKKY-like Spin Coupling in Spin-Gapless Mn$_2$CoAl/SiO$_2$/p-Si Heterostructures
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-01-12 20:00 EST
Nilay Maji, Subham Mohanty, Pujarani Dehuri
Here, we report spin-selective transport and exceptionally large positive junction magnetoresistance (JMR) in sputter-deposited Mn$ _2$ CoAl/native-SiO$ _2$ /p-Si heterostructures. Highly ordered inverse-Heusler Mn$ _2$ CoAl thin films with near-ideal XA chemical ordering ($ S \approx 0.97$ ) and a Curie temperature of $ \sim \SI{590}{\kelvin}$ are realized using a magnetron sputtering process. The spin-gapless semiconducting nature of Mn$ _2$ CoAl is experimentally supported by a weakly temperature-dependent resistivity with a very small negative temperature coefficient of resistance (TCR $ \approx -4.2 \times 10^{-9}$ ~$ \si{\ohm\meter\per\kelvin}$ ) and a nonsaturating linear magnetoresistance over a wide range of magnetic fields and temperatures.
A giant positive JMR of $ \sim \SI{825}{\percent}$ at \SI{10}{\kelvin} and $ \sim \SI{134}{\percent}$ at room temperature is observed despite the presence of only a single ferromagnetic electrode. Systematic variation of the SiO$ _2$ tunnel barrier thickness reveals a reproducible oscillatory sign reversal of the JMR accompanied by a monotonic decay in magnitude. This behavior reflects thickness-dependent modulation of spin-selective tunneling mediated by phase-coherent interfacial carriers and can be described phenomenologically by an RKKY-like functional form without invoking conventional metallic exchange interactions. These results identify Mn$ _2$ CoAl/native-SiO$ _2$ /p-Si heterostructures as robust and scalable platforms for room-temperature spin-selective transport, with potential applications in semiconductor-compatible spin filters, magnetic field sensors, and reconfigurable spintronic logic elements.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Interacting electrons in silicon quantum interconnects
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-01-12 20:00 EST
Anantha S. Rao, Christopher David White, Sean R. Muleady, Anthony Sigillito, Michael J. Gullans
Coherent interconnects between gate-defined silicon quantum processing units are essential for scalable quantum computation and long-range entanglement. We argue that one-dimensional electron channels formed in the silicon quantum well of a Si/SiGe heterostructure exhibit strong Coulomb interactions and realize strongly interacting Luttinger liquid physics. At low electron densities, the system enters a Wigner regime characterized by dominant 4kF correlations; increasing the electron density leads to a crossover from the Wigner regime to a Friedel regime with dominant 2kF correlations. We support these results through large-scale density matrix renormalization group (DMRG) simulations of the interacting ground state under both screened and unscreened Coulomb potentials. We propose experimental signatures of the Wigner-Friedel crossover via charge transport and charge sensing in both zero- and high-magnetic field limits. We also analyze the impact of short-range correlated disorder - including random alloy fluctuations and valley splitting variations - and identify that the Wigner-Friedel crossover remains robust until disorder levels of about 400 micro eV. Finally, we show that the Wigner regime enables long-range capacitive coupling between quantum dots across the interconnect, suggesting a route to create long-range entanglement between solid-state qubits. Our results position silicon interconnects as a platform for studying Luttinger liquid physics and for enabling architectures supporting nonlocal quantum error correction and quantum simulation.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Disordered Systems and Neural Networks (cond-mat.dis-nn), Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
19 pages, 10 figures, initcommit
Competing Paramagnetic Phases in the Maple-Leaf Heisenberg Antiferromagnet
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-01-12 20:00 EST
P. L. Ebert, Y. Iqbal, A. Wietek
We establish a remarkably rich ground state phase diagram in the maple-leaf lattice spin-$ 1/2$ Heisenberg antiferromagnet as a function of the three symmetry-inequivalent nearest-neighbor bonds using exact diagonalization and tower-of-states analysis on clusters up to $ N=36$ sites. Besides a hexagonal plaquette state, a star-shaped valence bond solid state is discovered in close vicinity to the (canted) $ 120^\circ$ magnetic phase, strongly reminiscent of a de-confined critical point or Dirac spin liquid scenario on the triangular lattice antiferromagnets. Moreover, an exact dimer product-state is observed next to a collinear Néel-state, similar to the Shastry-Sutherland model. All identified phases compete in a parameter regime close to the isotropic point, providing a promising region for spin liquids to emerge. By analyzing Gutzwiller-projected wave-functions we identify a sliver of parameter regime where a gapped $ \mathbb{Z}_{2}$ spin liquid Ansatz is in astonishing agreement with the exact $ N=36$ ground state. This rich competition of paramagnetic phases demonstrates that the maple-leaf antiferromagnet is a promising platform for exotic states of matter and quantum critical phenomena.
Strongly Correlated Electrons (cond-mat.str-el)
12 pages, 8 figures
Spin-triplet paired Wigner crystal stabilized by quantum geometry
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-01-12 20:00 EST
Dmitry Zverevich, Alex Levchenko, Ilya Esterlis
We have used variational states to analyze the effects of band geometry on the two-dimensional Wigner crystal with one and two electrons per unit cell. At sufficiently low electron densities, we find that increasing Berry curvature drives a transition into a crystalline state composed of spin-triplet pairs carrying relative orbital angular momentum $ m=-1$ . The essential features of this transition are captured by an effective two-electron quantum dot problem in the presence of Berry curvature. Our results point to a purely electronic, strong-coupling mechanism for local spin-triplet pairing in correlated two-dimensional electron systems with quantum geometry.
Strongly Correlated Electrons (cond-mat.str-el)
5 pages, 3 figures + supplemental material
Oxygen distribution and segregation at grain boundaries in Nb and Ta-encapsulated Nb thin films for superconducting qubits
New Submission | Superconductivity (cond-mat.supr-con) | 2026-01-12 20:00 EST
Jaeyel Lee, Dieter Isheim, Zuhawn Sung, Francesco Crisa, Sabrina Garattoni, Mustafa Bal, Cameron J. Kopas, Josh Y. Mutus, Hilal Cansizoglu, Jayss Marshall, Kameshwar Yadavalli, Dominic P. Goronzy, Mark C. Hersam, David N. Seidman, Alex Romanenko, Anna Grassellino, Akshay A. Murthy
We report on atomic-scale analyses of oxygen distribution and segregation at grain boundaries (GBs) of Nb and Ta-encapsulated Nb (Ta/Nb) thin films for superconducting qubits using atom-probe tomography (APT) and transmission electron microscopy (TEM). We observe oxygen segregation at grain boundaries (GBs) relative to the oxygen concentration within the grains for both Nb and Ta-capped Nb thin films for superconducting qubits and find that higher oxygen concentration in the interior of Nb grains lead to greater oxygen segregation levels at GBs. This finding emphasizes that controlling oxygen impurities in Nb during film deposition and fabrication processing is important to reduce the level of oxygen segregation at GBs in Nb. The enrichment factor (Cgb/Cgrain) for oxygen segregation at GBs in Nb is 2.7 (error bar: 0.3) for Nb films, and Ta-capped Nb thin films exhibit slightly reduced Nb GB enrichment factors of 2.3 (error bar: 0.3) while GBs in the Ta capping layer itself possess higher enrichment factors of 3.0 (error bar: 0.3). We hypothesize that the Ta capping layer can trap oxygen and thereby affect oxygen in-diffusion and segregation at GBs in the underlying Nb thin films. Finally, we find that increases in the oxygen concentration in both Nb grains and GBs correlate with a suppression in the critical temperature for superconductivity (Tc). Together, our comparative chemical and charge transport property analyses provide atomic-scale insights into a potential mechanism contributing to decoherence in superconducting qubits.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci)
Layered CrGe1-xSe3+y with Cr Kagome Lattice and Antiferromagnetic Ordering
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-01-12 20:00 EST
Jeremy G. Philbrick, Chaoguo Wang, Xin Gui, Tai Kong
We report the synthesis and properties of a new layered material, CrGe1-xSe3+y. The crystal structure was determined by using single crystal x-ray diffraction and transmission electron microscopy. CrGe1-xSe3+y crystallizes with a space group R-3m, featuring a double Kagome layer of chromium atoms, sandwiched between disordered Ge-Se layers. This compound displays antiferromagnetic order below 50 K, unlike the ferromagnetic behavior in CrGeTe3. Chromium displays an effective moment of ~3.9 {\mu}B/Cr, consistent with Cr3+ oxidation. The presence of this phase limits the possibility of a ferromagnetic CrGeSe3 analogous to CrGeTe3.
Materials Science (cond-mat.mtrl-sci)
22 pages, 5 figures
Phys. Rev. Materials 10 (2026) 014403
Emission Dynamics of Rydberg Excitons in $\mathbf{\mathrm{Cu_2O}}$: Distinguishing Second Harmonic Generation from Secondary Emission
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-01-12 20:00 EST
Kerwan Morin, Poulab Chakrabarti, Delphine Lagarde, Maxime Mauguet, Sylwia Zielińska - Raczyńska, David Ziemkiewicz, Xavier Marie, Thomas Boulier
Rydberg excitons in $ \mathrm{Cu_2O}$ simultaneously give rise to two very different optical responses under resonant two-photon excitation: a coherent second-harmonic signal mediated by the excitonic second order susceptibility tensor $ \chi^{(2)}$ , and a secondary emission originating from the radiative decay of real exciton populations. Distinguishing these two channels is essential for interpreting nonlinear and quantum-optical experiments based on high-$ n$ states, yet their temporal, spectral, and power-dependent signatures often overlap. Here we use time-resolved resonant two-photon excitation to cleanly separate SHG and SE and to map how each depends on $ n$ , temperature, excitation power, and crystal quality. This approach reveals the markedly different sensitivities of the two processes to phonons, defects, and many-body effects, and establishes practical criteria for identifying SE and SHG in a wide range of experimental conditions. Our results provide a unified framework for interpreting emission from Rydberg excitons and offer guidelines for future studies aiming to exploit their nonlinear response and long-range interactions.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
A finite viscoelastic constitutive model for low to high strain rate response of elastomers with application of strain rate-induced glass transition
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-01-12 20:00 EST
Bibekananda Datta, Sushan Nakarmi, Nitin P. Daphalapurkar
Amorphous elastomers exhibit significant rate-stiffening and unique viscous flow characteristics across a wide range of strain rates, often undergoing glass transition above a strain rate threshold. We have developed a thermodynamically-consistent and micromechanically-inspired constitutive model for soft elastomeric materials to capture the rate-dependent stress-strain behavior and hysteresis when subjected to low to high strain rates. Our proposed constitutive model encapsulates the viscous flow of materials through molecular motion at low strain rates and local rearrangement and alignment at high strain rates, essentially covering the glass transition. We applied our constitutive model to uniaxial compression experiments performed at low and high strain rates for polyborosiloxane (PBS) to identify the material parameters, and subsequently, performed numerical simulations of single and multi-cycle compression, stress relaxation, and small amplitude oscillatory tension-compression. Our analyses indicate that the model predicts higher total energy dissipation with increasing strain rate; however, dissipation associated with molecular relaxation decreases (forming a cusp) because, beyond a crossover strain rate, molecular rearrangement and alignment become dominant, which is consistent with the onset of the glass transition. For cyclic loading-unloading, we observed that dissipation over a cycle remains constant at low strain rate but decreases non-monotonically at high strain rates before becoming constant with peak stress over the cycle becoming higher, which can be interpreted as more loading being carried elastically by the polymer network as the molecular rearrangement process occurs. Additionally, our model was able to predict the qualitative nature of the storage modulus and loss modulus in the limit of small strain over a wide range of frequency sweeps.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
33 pages, 7 figures, journal pre-print
Magnetic switching of exciton lifetime in CrSBr
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-01-12 20:00 EST
Ina V. Kalitukha, Ilya A. Akimov, Mikhail O. Nestoklon, Torsten Geirsson, Alejandro Molina-Sánchez, Eyüp Yalcin, Claudia Ruppert, Daniel A. Mayoh, Geetha Balakrishnan, Muthumalai Karuppasamy, Zdeněk Sofer, Yadong Wang, Daniel J. Gillard, Xuerong Hu, Alexander I. Tartakovskii, Manfred Bayer
Exciton dynamics in layered magnetic semiconductors provide a sensitive probe of the interplay between spin order and light-matter interaction. Here, we study thin CrSBr layers using time-resolved photoluminescence spectroscopy in an external magnetic field, revealing a step-like reduction in the exciton lifetime from 11 to 7 ps, during the magnetization flip from the antiferromagnetic to the ferromagnetic phase. The reduction of the exciton lifetime in the ferromagnetic phase persists below the Néel temperature, as evidenced by its strong magnetic-field dependence that disappears in the paramagnetic phase. Ab initio calculations reveal a one-dimensional nature of free excitons accompanied by a pronounced change in the oscillator strength across the magnetic phase transition predicting a shorter radiative lifetime of free excitons in the antiferromagnetic phase of CrSBr contradicting the experimental observations. This discrepancy is explained by strong localization of excitons at low tempature. We show both experimentally and theoretically that the observed magnetic switching of the exciton lifetime is attributed to a larger exciton localization volume leading to a larger oscillator strength in the ferromagnetic phase. The results show that disorder-induced localization effects play a key role in exciton dynamics in CrSBr.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Multi-resonant non-dispersive infrared gas sensing: breaking the selectivity and sensitivity tradeoff
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-01-12 20:00 EST
Emma R. Bartelsen, J. Ryan Nolen, Christopher R. Gubbin, Mingze He, Ryan W. Spangler, Joshua Nordlander, Katja Diaz-Granados, Simone De Liberato, Jon-Paul Maria, James R. McBride, Joshua D. Caldwell
In applications such as atmospheric monitoring of greenhouse gases and pollutants, the detection and identification of trace concentrations of harmful gases is commonly achieved using non-dispersive infrared (NDIR) sensors. These devices employ a broadband infrared emitter, thermopile detector, and a spectrally selective bandpass filter tuned to the vibrational resonance of the target analyte. However, the fabrication of these filters is costly and limited to a single frequency. This limitation introduces a fundamental tradeoff, as broadening the optical passband width enhances sensitivity but compromises selectivity, whereas narrowing improves selectivity at the expense of sensitivity. In this work, we validate a filterless NDIR approach using a multi-peak thermal emitter developed through inverse design. This emitter enhances detection sensitivity by targeting multiple absorption bands, demonstrated through the creation of a sensor designed for the C-H vibrational modes of propane. Additionally, a set of single-peak emitters were developed to showcase the capability of designing highly selective sensors operating within close spectral proximity. These emitters, targeting the stretching modes of carbon monoxide and carbon dioxide, exhibit Q-factors above 50 and minimal crosstalk, enabling accurate detection of the target gas without interference from gases with spectrally adjacent absorption bands. This is enabled by the implementation of an aperiodic distributed Bragg reflectors, which allows for higher Q-factors with fewer layers than a periodic Bragg reflector using the same materials and number of layers, thereby reducing fabrication complexity and cost. Experimental results validate that this approach breaks the tradeoff between sensitivity and selectivity. This work highlights the potential of optimized thermal emitters for more efficient and compact gas sensing applications.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
The effect of normal stress on stacking fault energy in face-centered cubic metals
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-01-12 20:00 EST
Plastic deformation and fracture of FCC metals involve the formation of stable or unstable stacking faults (SFs) on (111) plane. Examples include dislocation cross-slip and dislocation nucleation at interfaces and near crack tips. The stress component normal to (111) plane can strongly affect the SF energy when the stress magnitude reaches several to tens of GPa. We conduct a series of DFT calculations of SF energies in six FCC metals: Al, Ni, Cu, Ag, Au, and Pt. The results show that normal compression significantly increases the stable and unstable SF energies in all six metals, while normal tension decreases them. The SF formation is accompanied by inelastic expansion in the normal direction. The DFT calculations are compared with predictions of several representative classical and machine-learning interatomic potentials. Many potentials fail to capture the correct stress effect on the SF energy, often predicting trends opposite to the DFT calculations. Possible ways to improve the ability of potentials to represent the stress effect on SF energy are discussed.
Materials Science (cond-mat.mtrl-sci)
Coupled Spin-lattice Dynamics across a Magnetostructural Phase Transition
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-01-12 20:00 EST
Lokanath Patra, Zeyu Xiang, Yubi Chen, Bolin Liao
First-order magnetostructural phase transitions underpin giant magnetocaloric effects, yet the microscopic role of lattice dynamics in these transitions remains controversial. Here we use first-principles spin-lattice dynamics simulations to investigate the coupled evolution of magnetization and phonon dispersions across the magnetostructural transition in MnAs. Our simulations quantitatively reproduce the experimentally observed Curie temperature, lattice contraction, and free-energy crossing between hexagonal and orthorhombic phases. We show that below the Curie temperature, magnetic-field-induced hardening of soft phonon modes gives rise to a sizable lattice entropy contribution that enhances the total isothermal entropy change by approximately 23% under a 5 T field. In contrast, the lattice entropy change associated with the structural phase transition itself has an opposite sign and partially compensates the lattice contribution due to field-induced phonon hardening. This competition reconciles long-standing discrepancies in the interpretation of magnetocaloric entropy measurements across first-order transitions. In addition, we demonstrate that the strong magnetic-field dependence of the phonon spectrum near the transition enables large tunability of lattice thermal conductivity, highlighting MnAs as a promising platform for magnetic-field-controlled thermal switching. Our results establish a unified microscopic picture of spin-lattice coupling in first-order magnetocaloric materials and provide design principles for engineering enhanced caloric and thermal transport functionalities.
Materials Science (cond-mat.mtrl-sci)
Symmetry-engineered and electrically tunable in-plane anomalous Hall effect in oxide heterostructures
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-01-12 20:00 EST
Kunjie Dai, Zhen Wang, Wenfeng Wu, Feng Jin, Enda Hua, Nan Liu, Jingdi Lu, Jinfeng Zhang, Yuyue Zhao, Linda Yang, Kai Liu, Huan Ye, Qiming Lv, Zhengguo Liang, Ao Wang, Dazhi Hou, Yang Gao, Shengchun Shen, Jing Tao, Liang Si, Wenbin Wu, Lingfei Wang
The family of Hall effects has long served as a premier probe of how symmetry, magnetic order, and topology intertwine in solids. Recently, the in-plane anomalous Hall effect (IP-AHE), a transverse Hall response driven by in-plane magnetization, has emerged as a distinct member of this family, offering innovative spintronic functionalities and illuminating intricate interplay between mirror-symmetry breaking and in-plane magnetic order. However, practical routes to deterministically and reversibly control IP-AHE remain limited. Here, we establish a symmetry-engineered IP-AHE platform, CaRuO3/La2/3Ca1/3MnO3/CaRuO3 heterostructure on NdGaO3(110), that turns strict mirror-symmetry breaking constraints into effective tuning knobs. IP-AHE in these epitaxial trilayers unambiguously couples to the CaRuO3-buffer-induced mirror-symmetry breaking and faithfully reproduces the ferromagnetic hysteresis. Ionic liquid gating further enables reversible reconfigurations of the symmetry breaking, thereby achieving electrical modulation and ON/OFF switching of IP-AHE. This highly tunable IP-AHE platform opens pathways for exploring nontrivial magnetic order and developing programmable Hall functionalities in planar geometries.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Intertwined atomic-nanoscale-microscale structures via intralayer anisotropic Fe-chains in the layered ferromagnet FePd2Te2
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-01-12 20:00 EST
Manyu Wang, Chang Li, Bingxian Shi, Shuo Mi, Xiaoxiao Pei, Shuming Meng, Yanyan Geng, Fei Pang, Rui Xu, Li Huang, Wei Ji, Hong-Jun Gao, Peng Cheng, Le Lei, Zhihai Cheng
Controlling mesoscale and nanoscale material structures and properties through self-organized atomic behavior is essential for atomic-scale manufacturing. However, direct and visual studies on the cross-scale effects of such atomic self-organization on mesoscopic structures remain scarce. Here, we report the intertwined atomic-nanoscale-mesoscale structures via the intralayer Fe-chains in the sandwich-like layered FePd2Te2 crystal by scanning tunneling microscopy (STM) and atomic force microscopy (AFM). The hierarchical orthogonal corrugated morphologies are directly revealed and attributed to its chain-orientation-determined twinning-domain effect. Both Fe-chains of middle-sublayer and two kinds of Te atoms of top-sublayer are further atomically resolved at the sub-Å level, indicating the critical effects of Pd-atoms/voids on the intra-layer anisotropic Fe-chains and the interlayer structural alignment. The thermal-induced and strain-related structural transitions of surface layer are further investigated and discussed based on the proposed filling model of Pd-voids by the intralayer Pd-atoms. Our work not only provides deep understanding of this exotic layered magnetic material, and will inspire more perspectives for tailoring its anisotropic atomic-to-mesoscale structures and properties.
Materials Science (cond-mat.mtrl-sci)
19 pages,4 figures
Revival of Strain Susceptibilities: Magnetostrictive Coefficient and Thermal-Expansion Coefficient
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-01-12 20:00 EST
In thermodynamics, volume is an essential extensive variable. Strain-line, area, or volume change-therefore offers a direct window into correlated quantum matter: tiny length changes {\Delta}L track how the lattice responds when state variables such as magnetic field H and/or temperature T are varied, revealing phases, transitions, and dynamics. Direct, high-precision strain measurements are already difficult; their susceptibilities are harder still. Very recently, several direct techniques have made vital progress on two key quantities: the magnetostrictive coefficient d{\lambda}/dH (often denoted qijk or dij in the magnetostriction literatures), and the linear thermal-expansion coefficient {\alpha}= d{\lambda}/dT. Considering these two strain susceptibilities together-they are fundamental and complementary-clarifies why these thermodynamic properties merit renewed attention.
Strongly Correlated Electrons (cond-mat.str-el)
Perspective, accepted in National Science Open
Anomalously High Phonon Thermal Conductivity Driven by Weak Electron-Phonon Coupling in Weyl Semimetals TaAs and TaP
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-01-12 20:00 EST
Xianyong Ding, Xin Jin, Dengfeng Li, Jing Fan, Peng Yu, Xiaoyuan Zhou, Xiaolong Yang, Rui Wang
In conventional metals, thermal transport is governed by electrons, with phonon contributions often considered negligible. Here, through rigorous first-principles calculations, we uncover a phonon-dominated thermal transport regime in the Weyl semimetals TaAs and TaP. Remarkably, although TaP is metallic, its phonon thermal conductivity ($ \kappa_{\text{ph}}$ ) reaches as high as 171 Wm$ ^{-1}$ K$ ^{-1}$ at room temperature, surpassing its electronic counterpart by more than a factor of five. This anomalously high $ \kappa_{\text{ph}}$ is enabled by the unique electronic and phononic band structures, characterized by the Weyl nodes near the Fermi level, together with acoustic phonon bunching and a wide frequency gap in the phonon spectrum, which collectively suppress phonon-electron and phonon-phonon scattering processes. Due to the substantial phonon contribution, the derived Lorenz number deviates strongly from the conventional Wiedemann-Franz law. We further show that the significance of phonon thermal transport is universal across topological semimetals. Our work provides deeper insight into thermal transport mechanisms in topological semimetals and extends the scope for discovering materials with high thermal conductivity.
Materials Science (cond-mat.mtrl-sci)
7pages,5figures
Autonomous Probe Microscopy with Robust Bag-of-Features Multi-Objective Bayesian Optimization: Pareto-Front Mapping of Nanoscale Structure-Property Trade-Offs
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-01-12 20:00 EST
Kamyar Barakati, Haochen Zhu, C Charlotte Buchanan, Dustin A Gilbert, Philip Rack, Sergei V. Kalinin
Combinatorial materials libraries are an efficient route to generate large families of candidate compositions, but their impact is often limited by the speed and depth of characterization and by the difficulty of extracting actionable structure-property relations from complex characterization data. Here we develop an autonomous scanning probe microscopy (SPM) framework that integrates automated atomic force and magnetic force microscopy (AFM/MFM) to rapidly explore magnetic and structural properties across combinatorial spread libraries. To enable automated exploration of systems without a clear optimization target, we introduce a combination of a static physics-informed bag-of-features (BoF) representation of measured surface morphology and magnetic structure with multi-objective Bayesian optimization (MOBO) to discover the relative significance and robustness of features. The resulting closed-loop workflow selectively samples the compositional gradient and reconstructs feature landscapes consistent with dense grid “ground truth” measurements. The resulting Pareto structure reveals where multiple nanoscale objectives are simultaneously optimized, where trade-offs between roughness, coherence, and magnetic contrast are unavoidable, and how families of compositions cluster into distinct functional regimes, thereby turning multi-feature imaging data into interpretable maps of competing structure-property trends. While demonstrated for Au-Co-Ni and AFM/MFM, the approach is general and can be extended to other combinatorial systems, imaging modalities, and feature sets, illustrating how feature-based MOBO and autonomous SPM can transform microscopy images from static data products into active feedback for real-time, multi-objective materials discovery.
Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG), Data Analysis, Statistics and Probability (physics.data-an)
25 pages, 5 figures
Cross-hatch strain effects on SiGe quantum dots for qubit variability estimation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-01-12 20:00 EST
Luis Fabián Peña, Mitchell I. Brickson, Fabrizio Rovaris, J. Houston Dycus, Anthony McDonald, Zachary T. Piontkowski, Joel Benjamin Ruzindana, Adelaide M. Bradicich, Don Bethke, Robin Scott, Thomas E. Beechem, Francesco Montalenti, N. Tobias Jacobson, Ezra Bussmann
SiGe heterostructures integrated with Si via virtual substrate (VS) growth are promising hosts for spin qubits. While VS growth targets plastic relaxation, residual cross-hatch strain inhomogeneity propagates into heterostructure overgrowth. To quantify strain inhomogeneity’s influence on interface structure and qubit properties, we measure strained-silicon (s-Si)/Si$ _{0.7}$ Ge$ _{0.3}$ heterostructures on 25 wafers processed via standard commercial chemical vapor deposition. Spatially-aligned images of strain (Raman microscopy) and interface structure (atomic force microscopy and cross-sectional scanning transmission electron microscopy) reveal strain-roughness interplay. A strain-driven surface diffusion model predicts the roughness and its temperature dependence. Measured strains suggest spurious double-dot qubit detunings of 0.1 meV over 100 nm distances may result. Modeling shows that interface roughness (atomic steps), when convolved with alloy disorder, only modestly reduces valley splitting (70$ \pm$ 13 vs. 77$ \pm$ 14 $ \mu$ eV on average). Our findings point to thicker VS buffer layers beneath heterostructures and lower-temperature growth (T $ \le$ 700 $ ^{\circ}$ C) to limit roughening.
Materials Science (cond-mat.mtrl-sci)
Molecular Orbital Degeneracy Lifting in a Tetrahedral Cluster System NbSeI
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-01-12 20:00 EST
Keita Kojima, Youichi Yamakawa, Ryutaro Okuma, Shunsuke Kitou, Hayato Takano, Jun-ichi Yamaura, Yusuke Tokunaga, Taka-hisa Arima, Yoshihiko Okamoto
The lifting of degenerate electronic states, in which multiple electronic states share the same energy, is a fundamental issue in the physics of crystalline solids. In real materials, this problem has been extensively studied in transition metal compounds, where various quantum phenomena arise from the spin and orbital degeneracy of the d electrons on individual transition-metal atoms. In contrast, materials containing high-symmetry clusters composed of multiple transition-metal atoms are expected to exhibit more emergent phenomena due to the entanglement of the electronic degrees of freedom across multiple atoms. Here, we report the discovery of two distinct mechanisms of orbital-degeneracy lifting in NbSeI, which comprises Nb4 tetrahedral clusters with molecular orbital degrees of freedom and whose average crystal structure is predicted to host a flat-band metal. Below 106 K, NbSeI is found to be a nonmagnetic molecular orbital-ordered insulator. Above this temperature, the average structure becomes face-centered cubic without any superlattice, while the orbital degeneracy remains lifted by significant local distortions of Nb4 tetrahedra, which may be associated with a molecular orbital-liquid or orbital-frozen state. This noncooperative Jahn-Teller distortion stabilizes a nonmagnetic insulating state above 106 K, in stark contrast to the flat-band metal predicted from the average structure.
Strongly Correlated Electrons (cond-mat.str-el)
Pattern formation in driven condensates
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-01-12 20:00 EST
Spontaneous pattern formation out of homogeneous media is one of the well-understood examples of hydrodynamic instabilities in classical systems, which naturally leads to the question of its manifestation in quantum fluids. Bose-Einstein condensates (BECs) of atomic gases have been an ideal platform for studying many-body quantum phenomena, such as superfluidity, and simultaneously providing an opportunity to broaden our understanding of classical hydrodynamics into quantum systems. In this review, we introduce a range of experimental studies on the pattern formation in quantum fluids of atomic gases under external driving, including Faraday waves in one and two dimensions, surface patterns, and counterflow instabilities in a mixture of superfluids. The pattern formation in the quantum system can be understood through the parametric amplification process, where an unstable dynamical mode can be exponentially amplified, similar to classical systems. Remarkably, the governing equations for surface excitations of trapped BECs can be mathematically equivalent to those of shallow water, indicating a universal description of the hydrodynamic instability across classical and quantum domains. However, the condensates, as superfluids, also possess fundamental quantum characteristics, such as quantized vorticity and a distinct dissipation channel. These unique features showcase many-body fragmentation under strong modulation and the generation of vortices in the nonlinear regime, which could offer a pathway to the study of quantum turbulence. Furthermore, the coexistence of long-range phase coherence and density modulation in driven condensates could provide unexplored features, such as those seen in supersolid-like sound modes, within nonequilibrium settings.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
This manuscript will appear in the Springer book entitled “Short and Long Range Quantum Atomic Platforms - Theoretical and Experimental Developments.”
Autonomous Discovery of the Ising Model’s Critical Parameters with Reinforcement Learning
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-01-12 20:00 EST
Hai Man, Chaobo Wang, Jia-Rui Li, Yuping Tian, Shu-Gang Chen
Traditional methods for determining critical parameters are often influenced by human factors. This research introduces a physics-inspired adaptive reinforcement learning framework that enables agents to autonomously interact with physical environments, simultaneously identifying both the critical temperature and various types of critical exponents in the Ising model with precision. Interestingly, our algorithm exhibits search behavior reminiscent of phase transitions, efficiently converging to target parameters regardless of initial conditions. Experimental results demonstrate that this method significantly outperforms traditional approaches, particularly in environments with strong perturbations. This study not only incorporates physical concepts into machine learning to enhance algorithm interpretability but also establishes a new paradigm for scientific exploration, transitioning from manual analysis to autonomous AI discovery.
Statistical Mechanics (cond-mat.stat-mech), Machine Learning (cs.LG), Computational Physics (physics.comp-ph)
37 pages, 9 figures. This is the Accepted Manuscript of an article published in J. Stat. Mech
J. Stat. Mech. (2025)
Symmetry-Driven Unconventional Magnetoelectric Coupling in Perovskite Altermagnets: From Bulk to the Two-Dimensional Limit
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-01-12 20:00 EST
Zhou Cui, Ziye Zhu, Xunkai Duan, Bowen Hao, Xianzhang Chen, Jiayong Zhang, Tong Zhou
The emergence of altermagnets establishes a new paradigm for multiferroics. Unlike conventional multiferroics relying on direct magnetoelectric coupling, multiferroic altermagnets host a crystal-symmetry-mediated magnetoelectric interaction that is intrinsically more efficient and robust. Among candidate material platforms, layered perovskites are particularly appealing owing to their structural diversity and synthetic versatility. However, magnetoelectric properties at the two-dimensional scale remain largely unexplored, hindering their applicability in miniaturized, highly integrated devices. Here, we systematically investigate the dimensional evolution of ferroelectric polarization and magnetism in perovskite systems through symmetry analysis. We demonstrate that altermagnetism can persist in the two-dimensional limit, yet is strongly constrained by the magnetic configuration-with only C-type antiferromagnetic order supporting it. Based on mode-decomposition calculations, we further reveal that symmetry-restricted multimode couplings simultaneously govern ferroelectric polarization and altermagnetic spin splitting. Finally, combined with first-principles calculations, we propose several strategies to lift the magnetic-configuration constraint, extending the range of viable altermagnetic systems. These results underscore the critical role of dimensionality in symmetry-driven magnetoelectric coupling in perovskite altermagnets and pave the way toward next-generation electrically controlled spintronic and multiferroic devices.
Materials Science (cond-mat.mtrl-sci)
7 pages, 4 figures
Precipitate size evolution in an ultrafine-grained magnesium-manganese alloy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-01-12 20:00 EST
Julian M. Rosalie, Brian R. Pauw, Anton Hohenwarter
Precipitate size evolution during room temperature high-pressure torsion (HPT) of a Mg-1.35wt.%Mn alloy was studied using scanning transmission electron microscopy (STEM) and Small-/Wide-angle X-ray scattering (SAXS/WAXS). The volume fraction of the nm-scale $ \alpha$ -Mn particles increased with applied strain, however small angle X-ray scattering (SAXS) indicated that the majority of manganese remained in solution even after 10 HPT rotations, indicating that the reaction progress is still limited by the diffusivity of Mn. Analysis of the precipitate size distribution determined that the mean particle size did not increase over the course of HPT. This, in combination with the precipitate size distribution suggested that precipitate growth was subject to interfacial rather than diffusional control.
Materials Science (cond-mat.mtrl-sci)
15 pages, 10 figures
Observation of Unconventional Ferroelectricity in Non-Moir’\e Graphene on Hexagonal Boron Nitride Boundaries and Interfaces
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-01-12 20:00 EST
Tianyu Zhang, Yueyang Wang, Hongxia Xue, Kenji Watanabe, Takashi Taniguchi, Dong-Keun Ki
Interfacial interactions in two parallel-stacked hexagonal boron-nitride (hBN) layers facilitate sliding ferroelectricity, enabling novel device functionalities. Additionally, when Bernal or twisted bilayer graphene is aligned with an hBN layer, unconventional ferroelectric behavior was observed, though its precise origin remains unclear. Here, we propose an alternative approach to engineering such an unconventional ferroelectricity in graphene-hBN van der Waals (vdW) heterostructures by creating specific types of hBN boundaries and interfaces. We found that the unconventional ferroelectricity can occur–without the alignments at graphene-hBN or hBN-hBN interfaces–when there are hBN edges or interfaces with line defects. By systematically analyzing the gate dependence of mobile and localized charges, we identified key characteristics of localized states that underlie the observed unconventional ferroelectricity, informing future studies. These findings highlight the complexity of the interfacial interactions in graphene/hBN systems, and demonstrate the potential for defect engineering in vdW heterostructures.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
16 pages, 5 figures. Supplementary Information included
Molecular signatures of pressure-induced phase transitions in a lipid bilayer
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-01-12 20:00 EST
Yanna Gautier, Guillaume Stirnemann, Jérôme Hénin
Understanding how lipid bilayers respond to pressure is essential for interpreting the coupling between membrane proteins and their native environments. Here, we use all-atom molecular dynamics to examine the pressure-temperature behavior of model membranes composed of DMPC or $ \Delta$ 9-cis-PC. Within the studied range (288-308 K, 1-2000 bar), DMPC undergoes a liquid–gel transition, while $ \Delta$ 9-cis-PC remains fluid due to unsaturation. The CHARMM36 force field reproduces experimental boundaries with high fidelity: simulated DMPC transitions deviate by only 5-10 K and 100-300 bar, and $ \Delta$ 9-cis-PC exhibits no transition. Hysteresis is modest but most pronounced when starting from low-temperature gels. We identify area per lipid, bilayer thickness, and acyl-chain gauche fraction as sensitive phase markers; among these, the gauche fraction provides the most robust signature. Simulations indicate an interdigitated gel is the equilibrium structure under finite-size conditions. However, at low temperature and high pressure, interdigitation decreases, consistent with the experimental lamellar gel phase. This long-lived interdigitation critically impacts standard order parameters, specifically area per lipid and membrane thickness. These results underscore the accuracy of modern force fields and highlight how simulations mechanistically complement experimental studies of pressure-regulated membranes.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph), Chemical Physics (physics.chem-ph)
NiTi Single Crystal Growth by Micro-Pulling-Down Method: Experimental Setup and Material Characterization
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-01-12 20:00 EST
Timon Sieweke, Chris Luther, Martin Wortmann, Lauritz Schnatmann, Felicitas Werner, Olga Kuschel, Laila Bondzio, Inga Ennen, Judith Bünte, Karsten Rott, Oluwaseyi Oluwabi, Moritz Loewenich, Joachim Wollschläger, Andreas Hütten, Jan Frenzel, Gabi Schierning, Alexander Kunzmann
Nickel-titanium that has an austenite to martensite phase transition has been studied extensively in the past as a shape memory alloy, but a lot remains to be learned from such phase transitions. However, single crystals are needed for a detailed characterization of the emerging phase transition. In order to produce NiTi single crystals for research purposes, we have set up a micro-pulling-down ($ \mu$ PD) apparatus. The $ \mu$ PD process is a fast and flexible method for the fabrication of small single crystals. The apparatus is operated in vacuum. By pulling the crystal down through a hole in the crucible bottom, it is possible to reduce oxygen contamination, since oxides float on top of the melt due to their low density. Here we present a detailed characterization of as-grown NiTi crystals by electron backscatter diffraction (EBSD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), hot gas extraction method and differential scanning calorimetry (DSC). The characteristics of the phase transition in NiTi are very sensitive to dopants and alloying. The $ \mu$ PD method facilitates the introduction of different doping elements into the crystal.
Materials Science (cond-mat.mtrl-sci)
Exact Theory of Fermi-Energy Response at Metallic Interfaces
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-01-12 20:00 EST
Théophane Bernhard, Andrea Grisafi
The response of the Fermi energy to external perturbations governs key physical observables at metallic interfaces. Although this response admits a local formulation in terms of the Fukui function, its evaluation has traditionally been limited by inherent approximations, fundamentally rooted in the difficulty of adding a finite charge in a periodic system. We present an exact resolution to this problem that leverages the screening properties of electronic conductors to compute Fukui functions via a finite electric field. The resulting linear-response theory yields strictly quadratic error scaling of Fermi-level shifts across representative platinum surfaces, achieving sub-meV accuracy up to fields of 0.1 V/Å. The approach is further validated by reproducing work-function changes under molecular perturbations, and by providing mean-field estimates of electrode potentials that yield capacitance–voltage curves consistent with experiment. Our findings establish a rigorous foundation for a local theory relating electrostatic screening and Fermi-energy variations at metallic interfaces.
Materials Science (cond-mat.mtrl-sci)
5 pages, 4 figures
Topological Superconductivity in Altermagnetic Heterostructures on a Honeycomb Lattice
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-01-12 20:00 EST
George McArdle, Brian Kiraly, Peter Wadley, Adam Gammon-Smith
Altermagnet-superconductor heterostructures have been shown, in principle, to provide a route towards realising topological superconductivity, and therefore host topologically protected boundary states. In this work we demonstrate that the topological states observed are dependent on the structure of the underlying lattice. By deriving and analysing a model on a honeycomb lattice, we demonstrate that the topological phase diagram has a rich structure containing both chiral edge modes and Majorana corner modes, the latter of which are an indication of higher-order topology. We analyse the effect of disorder on these states and find that whilst the edge modes are robust to a disordered system, any potential observation of the corner modes may be sensitive to the microscopic details. In particular, we show that vacancies can lead to other low energy bound states that may be difficult to distinguish from the corner modes.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
12 pages, 11 figures
Joint Optimization of Neural Autoregressors via Scoring rules
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-01-12 20:00 EST
Non-parametric distributional regression has achieved significant milestones in recent years. Among these, the Tabular Prior-Data Fitted Network (TabPFN) has demonstrated state-of-the-art performance on various benchmarks. However, a challenge remains in extending these grid-based approaches to a truly multivariate setting. In a naive non-parametric discretization with $ N$ bins per dimension, the complexity of an explicit joint grid scales exponentially and the paramer count of the neural networks rise sharply. This scaling is particularly detrimental in low-data regimes, as the final projection layer would require many parameters, leading to severe overfitting and intractability.
Soft Condensed Matter (cond-mat.soft), Artificial Intelligence (cs.AI)
First-principles analysis of in-plane anomalous Hall effect using symmetry-adapted Wannier Hamiltonians and multipole decomposition
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-01-12 20:00 EST
Hiroto Saito, Takashi Koretsune
The in-plane anomalous Hall effect occurs when magnetization lies within the same plane as the electric field and Hall current, and requires magnetic point groups lacking rotational or mirror symmetries. While it is observed in both Weyl semimetals and elemental ferromagnets, the microscopic role of higher-order multipoles remains unclear. Here, we develop a microscopic framework that combines time-reversal-symmetric Wannier functions with a symmetry-adapted multipole basis to decompose the first-principles Wannier Hamiltonian into electric, magnetic, magnetic toroidal, and electric toroidal multipoles. This approach allows us to rotate the magnetization rank by rank and quantify how each multipole affects the conductivity. Applying this framework to body-centered cubic iron, we find that high-rank magnetic and magnetic toroidal multipoles contribute with magnitudes comparable to magnetic dipoles, while magnetic toroidal 16-poles act with the opposite sign. Furthermore, based on this multipole analysis, we apply uniaxial strain along the [103] direction to control the dominant multipoles contributing to the conductivity. The strain substantially modifies its angular dependence, demonstrating that multipole-resolved Hamiltonian engineering and magnetoelastic control serve as practical routes to predict and tune the in-plane anomalous Hall conductivity in simple ferromagnets.
Materials Science (cond-mat.mtrl-sci)
Quantized heat flow in the Hofstadter butterfly
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-01-12 20:00 EST
Aifei Zhang, Gibril Aissani, Quan Dong, Yong Jin, Kenji Watanabe, Takashi Taniguchi, Carles Altimiras, Patrice Roche, Jean-Marc Berroir, Emmanuel Baudin, Gwendal Fève, Gerbold Ménard, Olivier Maillet, François D. Parmentier
When subjected to a strong magnetic field, electrons on a two-dimensional lattice acquire a fractal energy spectrum called Hofstadter’s butterfly. In addition to its unique recursive structure, the Hofstadter butterfly is intimately linked to non-trivial topological orders, hosting a cascade of ground states characterized by non-zero topological invariants. These states, called Chern insulators, are usually understood as replicas of the ground states of the quantum Hall effect, with electrical and thermal conductances that should be quantized, reflecting their topological order. The Hofstadter butterfly is now commonly observed in van-der-Waals heterostructures-based moiré superlattices. However, its thermal properties, particularly the quantized heat flow expected in the Chern insulators, have not been investigated, potentially questioning their similarity with standard quantum Hall states. Here we probe the heat transport properties of the Hofstadter butterfly, obtained in a graphene/hexagonal boron nitride moiré superlattice. We observe a quantized heat flow, uniquely set by the topological invariant, for all investigated states of the Hofstadter butterfly: quantum Hall states, Chern insulators, and even symmetry-broken Chern insulators emerging from strong electronic interactions. Our work firmly establishes the universality of the quantization of heat transport and its intimate link with topology.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Includes Supplementary Information
Mechanical control of magnetic exchange and response in GdRu$_2$Si$_2$: A computational study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-01-12 20:00 EST
Sagar Sarkar, Rohit Pathak, Arnob Mukherjee, Anna Delin, Olle Eriksson, Vladislav Borisov
We present a systematic computational study of the effect of uniaxial strain on the magnetic properties of GdRu$ 2$ Si$ 2$ , a centrosymmetric material known to host a field-induced skyrmion lattice (SkL). Using first-principles density functional theory, we first demonstrate the pronounced sensitivity of the exchange and anisotropy to specific structural distortions. These DFT-derived interactions are then integrated into a classical spin model to construct comprehensive magnetic phase diagrams under both compressive and tensile strain. Our key finding is that compressive strain ($ \sim 2%$ ) acts as an effective tuning parameter, substantially expanding the stability region of the $ \vec Q{100}$ -driven topologically nontrivial phases. This results from the shifts in the critical magnetic fields and enhancement of the energy scale of the favored magnetic wave vector. In contrast, tensile strain induces a different magnetic ground-state by promoting a different magnetic ordering vector, $ \vec Q{110}$ , leading to entirely distinct phase behavior. This work not only provides a quantitative understanding of the structural-magnetic coupling in GdRu$ _2$ Si$ _2$ but also establishes strain engineering as a powerful approach to control and optimize topologically non-trivial magnetic phases in centrosymmetric magnets.
Materials Science (cond-mat.mtrl-sci)
31 pages, 9 figures in the manuscript
Unraveling the effects of anionic vacancies and temperature on mechanical properties of NbC and NbN: Insights from Quantum Mechanical Study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-01-12 20:00 EST
P.W. Muchiri, K. K. Korir, N. W. Makau, M. O. Atambo, G. O. Amolo
Transition metal carbides and nitrides (TMCNs), such as niobium carbide (NbC) and niobium nitride (NbN), are of great technological interest due to their exceptional hardness, high melting points, and thermal stability. While previous studies have focused on their groundstate properties (at 0 K), limited information exists on their mechanical behavior under realistic operational conditions involving elevated temperatures and the presence of defects. In this study, we employ ab initio molecular dynamics (AIMD) simulations to investigate the effects of temperature (300 to 1500 K) and anionic vacancies on the mechanical properties of NbC and NbN in rocksalt (RS), zincblende (ZB), and wurtzite (WZ) structures. The results reveal a nonlinear decrease in elastic constants, bulk, shear, and Youngs moduli with both increasing temperature and defect concentration. Hardness and toughness analyses, based on Pughs ratio and Poisson ratio, show ductility and brittleness transitions that are sensitive to structure, defect level, and thermal effects. Furthermore, vacancy migration energies computed using the nudged elastic band (NEB) method demonstrate strong structural dependence, with RS exhibiting the highest barriers and WZ the lowest. These findings provide new insights into the defect and temperature interplay in NbC and NbN, offering guidelines for their optimization in high-temperature and wear-resistant applications.
Materials Science (cond-mat.mtrl-sci)
On the Novel Superfluidity in the Second Layer of $^4$He on Graphite
New Submission | Other Condensed Matter (cond-mat.other) | 2026-01-12 20:00 EST
Evidence for a new type of superfluid phase in second-layer $ ^4$ He on graphite has been obtained from simultaneous measurements of torsional-oscillator response and heat-capacity on exactly the same sample down to 30 mK, which resolve substrate-related uncertainties in the previous studies. The new phase hosts both superfluidity and enhanced viscoelasticity, and is stable over a finite density interval, strongly supporting the proposed superfluid liquid-crystal hypothesis. A random-Josephson-network analysis shows that the widely reported log-$ T$ dependence of the superfluid density is likely due to substrate imperfections.
Other Condensed Matter (cond-mat.other)
Manuscript combined with Supplementary Materials; 15 pages, 12 figures
Observation of magnon torques mediated by orbital hybridization at the light metal/antiferromagnetic insulator interface
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-01-12 20:00 EST
Yuchen Pu, Guoyi Shi, Hua Bai, Xinhou Chen, Chenhui Zhang, Zhaohui Li, Mehrdad Elyasi, Hyunsoo Yang
Magnon torques, which can operate without involving moving electrons, could circumvent the Joule heating issue. In conventional magnon torque systems, the spin source layer with strong spin-orbit coupling is utilized to inject magnons, and the efficiency is limited by the inherent spin Hall conductivity of the spin source layer. In this work, we observe magnon torques in the Cr/NiO/ferromagnet heterostructure with the effective spin Hall conductivity of 2.45x10^5 hbar/(2e{\Omega}m), twice that of the best conventional magnon torque system. We demonstrate the magnon-torque-driven switching of a perpendicularly magnetized CoFeB layer at room temperature, with a switching power consumption density of 0.136 mW/{\mu}m^2. We find that the magnon torque originates from the orbital hybridization and interfacial inversion symmetry breaking at the Cr/NiO interface. Our findings not only significantly enhance the efficiency of magnon torques, but also provide key insights into the fundamental mechanisms of magnon injections.
Materials Science (cond-mat.mtrl-sci)
4 figures
Quantum geometric scattering of a Dirac particle by a Berry curvature domain wall
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-01-12 20:00 EST
Lassaad Mandhour, Frédéric Piéchon
We investigate the scattering of a three-dimensional massless Dirac particle through a domain wall separating two regions with identical energy spectra but distinct Berry curvature dipoles. We demonstrate that the quantum geometric mismatch induces partial reflection and transmission despite identical incident and refracted momenta. These results highlight the role of engineered quantum geometric interfaces as key tools to control Dirac particle scattering.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
9 pages, 7 figures
Physica E 178 (2026) 116468
Spin dynamics of excitons and carriers in mixed-cation MA${x}$FA${1-x}$PbI$_{3}$ perovskite crystals: alloy fluctuations probed by optical orientation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-01-12 20:00 EST
B. F. Gribakin, N. E. Kopteva, D. R. Yakovlev, I. A. Akimov, I. V. Kalitukha, B. Turedi, M. V. Kovalenko, M. Bayer
Optical spin orientation measured by time-resolved photoluminescence provides a powerful tool to probe the spin dynamics of excitons and charge carriers in perovskite semiconductors. The impact of alloy fluctuations on the spin dynamics of mixed-cation \MAFAPI{} perovskite single crystals is studied here experimentally. The optical orientation is measured under nonresonant excitation for crystals with $ x = 0.1$ , $ 0.4$ , and $ 0.8$ at cryogenic temperatures and compared with data on \MAPI{} crystals. The high degree of exciton optical orientation of $ 75-80$ % for $ x = 0.1$ and $ 0.8$ reduces to about 60% for $ x = 0.4$ . A similar trend is observed for the carrier spin optical orientation. This behavior is attributed to enhanced scattering of free excitons and carriers in the alloys with increased compositional and structural disorder. From the Larmor spin precession measured from spin dynamics in an external magnetic field applied in the Voigt geometry, the electron and hole $ g$ -factors are evaluated. Their dependence on the band gap energy in \MAFAPI{} crystals follows the universal trend previously established for lead halide perovskites.
Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
Bio-resorbable magnetic tunnel junctions
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-01-12 20:00 EST
Dong-Jun Kim, Beom Jin Kim, Hee-Chang Shin, Jeongkeun Kim, Yuchen Pu, Shuhan Yang, Xinhou Chen, Byong-Guk Park, Jong-Hyun Ahn, Hyunsoo Yang
Magnetic tunnel junctions (MTJs) play a crucial role in spintronic applications, particularly data storage and sensors. Especially as a non-volatile memory, MTJs have received substantial attention due to its CMOS compatibility, low power consumption, fast switching speed, and high endurance. In parallel, bio-resorbable electronics have emerged as a promising solution for systems requiring temporary operation and secure data disposal, especially in military, intelligence, and biomedical systems where devices must safely disintegrate under physiological conditions. In this study, we investigate the bio-resorbability of MTJ by analyzing the dissolution behavior of its nanometer-thick constituent layers in phosphate-buffered saline (PBS) solution at pH 7.4, simulating physiological environments. The MTJ structures, composed of bio-resorbable materials, exhibit well-controlled degradation behaviors. Critically, as one of the ferromagnetic layers dissolves, binary information is irreversibly lost, within 10 hours of immersion. These findings highlight the potential of MTJs not only as high-performance memory elements but also as secure, transient data storage platforms. The ability to modify the dissolution lifetime by materials and thickness selection offers unique advantages for short-lived implantable devices, paving the way for integrating spintronic functionality into next-generation bioresorbable electronics.
Materials Science (cond-mat.mtrl-sci)
Structural and magnetic properties of co-sputtered epitaxial Fe-Sn kagome thin films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-01-12 20:00 EST
Callum Brennan-Rich, Sean M. Collins, Stuart Micklethwaite, Zabeada Aslam, Trevor Almeida, Stephen McVitie, Rik M. Drummond-Brydson, Christopher H. Marrows
In recent years the intermetallic alloys of Fe and Sn have gained significant interest due to a rich variety of magnetic properties present in these materials. The crystal Fe3Sn2 is a frustrated ferromagnet, while the crystallographically similar FeSn, which differs only by the stacking sequence of its Fe-containining kagome and stanene layers, is an antiferromagnet. Thin-film growth techniques such as magnetron sputtering allow for these different stoichiometric compositions to be grown through adjustments of the rate of deposition of the individual Fe and Sn sources, while all other conditions remain constant. Here, we report the production of high quality epitaxial thin films of Fe$ _3$ Sn$ _2$ and FeSn on sapphire with a Pt seed layer, as well as a mixed phase containing intergrowths of both crystals, all of which we have characterized using both X-ray and four-dimensional scanning transmission electron microscopy (4D-STEM) methods. The resulting crystallographic phase content is compared to the results of magnetization measurements, with correspondence between the predicted ferromagnetic phase content and the resulting magnetization. Further magnetic properties of these films can then also be compared, leading to the discovery of a unique behavior in the temperature dependent coercivity within highly mixed phase alloys, a feature that is absent in either pure Fe3Sn2 and FeSn.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
9 pages, 5 figures
Crystalline-dependent magnon torques in all-sputtered Hf/Cr2O3/ferromagnet heterostructures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-01-12 20:00 EST
Yuchen Pu, Guoyi Shi, Chenhui Zhang, Xinhou Chen, Hanbum Park, Hyunsoo Yang
Electron motion in spin-orbit torque devices inevitably leads to the Joule heating issue. Magnon torques can potentially circumvent this issue, as it enables the transport of spin angular momentum in insulating magnetic materials. In this work, we fabricate a sandwich structure composed of Hf/antiferromagnetic Cr2O3/ferromagnet and demonstrate that the magnon torque is strongly dependent on the crystalline structure of Cr2O3. Magnon torques are stronger when the Neel vector of Cr2O3 aligns parallel to the spin polarization generated in Hf, while they are suppressed when the Neel vector is perpendicular to the spin polarization. The magnon torque efficiency is estimated to be -0.134 using in-plane second harmonic Hall measurements. Using magnon torques, we achieve perpendicular magnetization switching of CoFeB, with a critical switching current density of 4.09 x 10^7 A/cm^2. Furthermore, the spin angular momentum loss due to the insertion of Cr2O3 is found to be lower than that of polycrystalline NiO. Our work highlights the role of antiferromagnet crystalline structures in controlling magnon torques, broadening the potential applications of magnon torques.
Materials Science (cond-mat.mtrl-sci)
Transport characteristics in Hermitian and non-Hermitian Fibonacci rings: A comparative study
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-01-12 20:00 EST
We present an extensive theoretical analysis of transport and circular currents and the associated induced magnetic fields in Fibonacci rings, explored in both Hermitian and non-Hermitian descriptions, with particular attention to configurations preserving or breaking PT symmetry. By engineering physically balanced gain and loss following a Fibonacci sequence, we realize two distinct geometrical configurations in which the ring either preserve or explicitly break PT symmetry, and further explore complementary realizations obtained by reversing the signs of the on site potentials. Using the non equilibrium Green’s function (NEGF) formalism, we analyze transmission properties and bond current densities to quantify both transport and circulating currents. A comparison with the Hermitian limit establishes a clear baseline, where the ring supports only weak responses upon introducing disorder. In sharp contrast, non-Hermiticity leads to a pronounced amplification of transport and circular currents, and hence of the induced magnetic field. We further demonstrate that non-Hermitian transport is highly sensitive to gain and loss sign reversal and, in the non-PT-symmetric case, exhibits an unconventional dependence on system size governed by the parity of the Fibonacci sequence and hopping correlations. Remarkably, the current does not decay monotonically with increasing system size, revealing a distinct scaling behavior absent in conventional Hermitian systems. Our results highlight non-Hermitian quasiperiodic rings as versatile platforms for engineering and amplifying current driven magnetic responses through symmetry, topology, and gain-loss design.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
14 Pages, 11 Figures
Phonon-induced Markovian and non-Markovian effects on absorption spectra of moiré excitons in twisted transition metal dichalcogenide bilayers
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-01-12 20:00 EST
Daniel Groll, Anton Plonka, Kevin Jürgens, Daniel Wigger, Tilmann Kuhn
The properties of moiré excitons in twisted bilayers of transition metal dichalcogenides (TMDCs) vary significantly with the twist angle, ranging from quasi localized excitons with flat dispersions for small twist angles to delocalized excitons for larger ones. This twist angle dependence directly impacts the exciton-phonon coupling, which plays a significant role for the optical properties of these materials. In this work we theoretically investigate the twist angle dependent influence of phonons on absorption spectra of intralayer moiré excitons in a twisted TMDC hetero-bilayer. For the lowest-lying intralayer moiré exciton we find that the exciton-phonon coupling interpolates between two physically distinct regimes when tuning the twist angle. At small twist angles non-Markovian polarization dynamics and phonon sidebands dominate the properties of absorption spectra for localized excitons. For larger twist angles Markovian processes become more important leading to additional line broadening. Furthermore, the absorption spectra here show a characteristic asymmetric peak similar to monolayer TMDCs. When taking into account multiple bright moiré exciton bands we find that intraband scattering due to optical phonons has a significant impact on absorption spectra, effectively suppressing absorption peaks of higher lying bands when their bandwidth surpasses the optical phonon energy.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Heterogeneous ice nucleation on model substrates
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-01-12 20:00 EST
Miguel Camarillo, Javier Oller-Iscar, María M. Conde, Jorge Ramírez, Eduardo Sanz
Ice nucleation is greatly important in areas as diverse as climate change, cryobiology, geology or food industry. Predicting the ability of a substrate to induce the nucleation of ice from supercooled water is a difficult problem. Here, we use molecular simulations to analyse how the ice nucleating ability is affected by the substrate lattice structure and orientation. We focus on different model lattices: simple cubic, body centred cubic and face centred cubic, and assess their ability to induce ice nucleation by calculating nucleation rates. Several orientations are studied for the case of the face centred cubic lattice. Curiously, a hexagonal symmetry does not guarantee a better ice nucleating ability. By comparing the body centred cubic and the cubic lattices we determined that there is a significant role of the underlying crystal plane(s) on ice nucleation. The structure of the liquid layer adjacent to the substrate reveals that more efficient nucleants induce a more structured liquid. The most efficient substrates present a strong sensitivity of their ice nucleating ability to the lattice parameters. Introducing a novel methodological approach, we use Classical Nucleation Theory to estimate the contact angle of the ice nucleus on the studied substrates from the calculated nucleation rates. The method also provides the nucleation free energy barrier height, the kinetic pre-factor and the critical cluster size. The latter is in agreement with the nucleus size obtained through a microscopic analysis of the nucleation trajectories, which supports the validity of Classical Nucleation Theory down to small critical clusters.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
12 figures, 87 references
J. Chem. Phys. 163, 154504 (2025)
Noncollinear spin structure in Dy-doped classical ferrimagnet
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-01-12 20:00 EST
Anupam K. Singh, Katayoon Mohseni, Verena Ney, Andreas Ney, Yicheng Guan, Ilya Kostanovski, Malleshwararao Tangi, Mostafa I. S. Marzouk, Manuel Valvidares, Pierluigi Gargiani, Jean-Marc Tonnerre, P. F. Perndorfer, P. A. Buczek, Arthur Ernst, Holger L. Meyerheim, Stuart S. P. Parkin
Noncollinear spin structures have attracted tremendous attention because they offer a versatile platform for spin control and manipulation, essential in spintronics. Realizing noncollinearity in ferrimagnetic insulators is of particular interest as they can be potentially utilized in low-damping spintronics with tunable magnetic order. Within the spinel-ferrite family, Zn and Al-substituted nickel ferrite (NiZAF) has emerged as an excellent choice for low-damping spintronics. However, realizing noncollinearity in such systems remains challenging. Here, we present evidence of noncollinear spin structure in the NiZAF thin films induced by the rare earth Dy-doping, utilizing the soft x-ray spectroscopy methods such as magnetic circular dichroism and x-ray resonant magnetic reflectivity (XRMR). In particular, XRMR reveals a spiral-type spin structure, which is attributed to the Dzyaloshinskii-Moriya interaction, arising due to broken inversion symmetry by the Dy-induced local strain field as confirmed by our theoretical calculations. The realization of noncollinearity in the spinel-ferrite opens pathway to explore the possibility of chiral magnetic domains and topological spin textures exhibiting promise for oxide-based spintronics
Materials Science (cond-mat.mtrl-sci)
Pressure-driven Valence evolution Coupled Hardening-to-Softening transition in YbPd
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-01-12 20:00 EST
B. Tegomo Chiogo, V. Balédent, J.-P. Rueff, Ethan Saïman, V. Poree, T. Schweitzer, D. Wong, C. Schulz, T. Mazet, A. Chainani, D. Malterre, K. Habicht
We investigate the Yb valence instabilities in the strongly correlated YbPd compound using resonant X-ray emission spectroscopy under pressure across the charge-ordering (CO) transition. At a low temperature (T = 30 K) in the CO ordered phase, the Yb $ 4f$ valence remains nearly constant up to a pressure P$ _K$ = 1.5 GPa, and then increases gradually at higher pressures. In contrast, at room temperature in the normal phase, an anomalous decrease of the Yb $ 4f$ valence is observed, without any accompanying structural phase transition. This behavior is corroborated by a systematic pressure dependent decrease of the unit-cell volume. Based on a Birch-Murnaghan analysis, the compressibility indicates hardening of the lattice with applied pressure up to a distinct kink seen at P$ _K$ = 1.5 GPa. In contrast, for P $ >$ P$ _K$ , the Yb $ 4f$ valency saturates and the compressibility reveals a counterintuitive pressure-induced softening. The results show a minimum in the compressibility of YbPd (with $ f^{13}$ -$ f^{14}$ hole-type mixed-valence) and is reminiscent of the maximum in compressibility seen in the $ \gamma$ -$ \alpha$ first-order isostructural phase transition in cerium (with $ f^{0}$ -$ f^{1}$ electron-type mixed-valence).
Strongly Correlated Electrons (cond-mat.str-el)
7 pages, 5 figures
Reservoir computing from collective dynamics of active colloidal oscillators
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-01-12 20:00 EST
Veit-Lorenz Heuthe, Lukas Seemann, Samuel Tovey, Clemens Bechinger
Physical reservoir computing is a computational framework that offers an energy- and computation-efficient alternative to conventional training of neural networks. In reservoir computing, input signals are mapped into the high-dimensional dynamics of a nonlinear system, and only a simple readout layer is trained. In most physical implementations, the interactions that give rise to the dynamics cannot be tuned directly and high dimensionality is typically achieved through time-multiplexing, which can limit flexibility and efficiency. Here we introduce a reservoir composed of hundreds of hydrodynamically coupled active colloidal oscillators forming a fully parallel physical reservoir and whose coupling strength and fading-memory time can be tuned in situ. The collective dynamics of the active oscillators allow accurate predictions of chaotic time series from single reservoir readouts without time-multiplexing. We further demonstrate real-time detection of subtle hidden anomalies that preserve all instantaneous statistical properties of the signal yet disrupt its underlying temporal correlations. These results establish interacting active colloids as a reconfigurable platform for physical computation and edge-integrated intelligent sensing for model-free detection of irregularities in complex time signals.
Soft Condensed Matter (cond-mat.soft), Applied Physics (physics.app-ph)
Nonlinear mode interactions under parametric excitation in a YIG microdisk
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-01-12 20:00 EST
Gabriel Soares, Rafael Lopes Seeger, Amel Kolli, Maryam Massouras, Titiksha Srivastava, Joo-Von Kim, Nathan Beaulieu, Jamal Ben Youssef, Manuel Muñoz, Ping Che, Abdelmadjid Anane, Salvatore Perna, Claudio Serpico, Massimiliano d’Aquino, Hugo Merbouche, Grégoire de Loubens
A pair of quantized spin-wave modes is driven by two-tone parallel pumping in a YIG microdisk. The nonlinear dynamics is experimentally investigated by probing the resulting steady state, which is found to critically depend on the chosen pair of modes, the detuning between the pump frequencies and the modes parametric resonance, as well as the temporal sequence of the two rf tones. A general theory of parametric excitation in confined structures based on magnetization normal modes is developed and quantitatively accounts for the observed dependence and non-commutative behaviors, which emerge from the interplay between the self and mutual nonlinear frequency shifts of the spin-wave modes. Owing to its high degree of external controllability and scalability to larger sets of modes, this dynamical system provides a model platform for exploring nonlinear phenomena and a promising route toward rf driven state mapping relevant to neuromorphic and unconventional computing.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
10 pages, 4 figures
Phase Frustration Induced Intrinsic Bose Glass in the Kitaev-Bose-Hubbard Model
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-01-12 20:00 EST
We report an intrinsic “Bubble Phase” in the two-dimensional Kitaev-Bose-Hubbard model, driven purely by phase frustration between complex hopping and anisotropic pairing. By combining Inhomogeneous Gutzwiller Mean-Field Theory with a Bogoliubov-de Gennes stability analysis augmented by a novel Energy Penalty Method, we demonstrate that this phase spontaneously fragments into coherent islands, exhibiting the hallmark Bose glass signature of finite compressibility without global superfluidity. Notably, we propose a unified framework linking disorder-driven localization to deterministic phase frustration, identifying the Bubble Phase as a pristine, disorder-free archetype of the Bose glass. Our results provide a theoretical blueprint for realizing glassy dynamics in clean quantum simulators.
Quantum Gases (cond-mat.quant-gas)
10 pages, 4 figures. Supplementary Material included
Gate-tunable charge-spin interconversion in graphene/heavy-metal heterostructures
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-01-12 20:00 EST
Zhendong Chi, Eoin Dolan, Haozhe Yang, Beatriz Martín-García, Marco Gobbi, Luis E. Hueso, Fèlix Casanova
Spintronics has emerged as a promising field for next-generation devices, offering functionalities beyond complementary metal-oxide-semiconductor (CMOS). A critical challenge in spintronics is to develop systems that can efficiently generate spin currents and enable their long-distance transport. Here, we demonstrate a graphene (Gr)/heavy metal (HM) heterostructure system that combines strong charge-spin interconversion efficiency, induced by the spin Hall effect, with a long spin diffusion length. By employing an industry-friendly magnetron sputtering technique, we deposit HM layers onto few-layer Gr while minimizing structural damage. The proximity effect from the HM enhances the spin Hall angle of Gr while limiting the reduction in its spin diffusion length. Additionally, the spin Hall angle can be tuned via an applied gate voltage, offering high controllability of the system. Importantly, these properties are observed across heterostructures composed of different HMs, indicating the generality of this approach. Our findings establish Gr/HM heterostructures as a scalable and versatile platform for spin current generation, paving the way for advanced spintronic devices with high efficiency, long spin propagation, and straightforward fabrication processes.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
8 pages, 5 figures, and Supplemental Material
Phys. Rev. Applied 24, 064076 (2025)
Early bloodmaterial interfacial events and capillary transport on nanoparticle modified nanofibers
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-01-12 20:00 EST
Romain Scarabelli, Mehdi Abbasi, Magali Gary-Bobo, Christophe Drouet, Marc Leonetti, Ahmed Al-Kattan
Electrospun poly(\epsilon-caprolactone) (PCL)nanofibrous mats are widely considered for blood-contacting wound dressings and small-diameter vascular applications; however, their intrinsic hydrophobicity limits rapid wetting and controlled interaction with blood. In this work, we modulate the interfacial response of PCL nanofibers by incorporating oxide-shelled silicon nanoparticles (SiNPs) synthesized by pulsed laser ablation in liquid, a ligand-free approach that avoids organic stabilizers and preserves surface reactivity. Two composite architectures were designed: SiNPs embedded within the fiber bulk (PAC1,4,16) and SiNPs preferentially exposed at the fiber surface (SPAC1,4,16), with systematically increasing nanoparticle loadings. Structural characterization confirmed the retention of a homogeneous fibrous morphology and the targeted nanoparticle distribution. The dynamic interaction with whole blood was quantified using time-resolved contact-angle measurements, complemented by top-view optical microscopy and three-dimensional profilometry of dried droplets. Pristine PCL remained strongly hydrophobic whereas a hydrophilic PCL functionalized with APTES showed rapid spreading. Incorporation of SiNPs within the fiber volume led to only a moderate enhancement of wettability, and dried droplets retained compact morphologies with limited spreading. In contrast, surface-decorated mats displayed a sharp, concentration-dependent transition toward highly wettable behavior: for SPAC16, the contact angle fell below 20, droplet profiles became markedly flattened, and microscopy revealed extended plasma-rich regions surrounding a red-cell-rich core, indicative of pronounced phase separation within the nanofibrous network.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
14 pages, 12 figures
Angular-Dependent Thermal Hall Effect in a Honeycomb Magnet: Disentangling Kitaev and Dzyaloshinskii-Moriya Interactions
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-01-12 20:00 EST
Shuvankar Gupta, Olajumoke Oluwatobiloba Emmanuel, Pengpeng Zhang, Xianglin Ke
Layered honeycomb magnets have garnered significant attention recently for their exotic quantum phenomena due to the potential anisotropic, bond-dependent Kitaev interactions. However, distinguishing the roles of Kitaev interactions and the symmetry-allowed Dzyaloshinskii-Moriya interaction (DMI) remains challenging, since both mechanisms may lead to similar magnetic excitations and thermal transport properties. To tackle this challenge, using a ferromagnetic honeycomb insulator VI3 as a model system, we systematically study the angular-dependent thermal Hall conductivity Kxy({\theta}, {\Phi}) with both out-of-plane ({\theta}) and in-plane ({\Phi}) magnetic field rotations. Our results reveal a persistent thermal Hall response for both out-of-plane and in-plane rotating magnetic fields, devoid of the sign-reversal patterns characteristic of Kitaev physics. Instead, quantitative analysis shows that the angular dependent Kxy({\theta}, {\Phi}) is governed by the projection between the magnetic moment and a tilted DM vector containing both out-of-plane and in-plane components. These results not only establish the DMI-driven topological magnetic excitations as the origin of the thermal Hall response in VI3 but also highlight the angular-dependent thermal Hall effect measurements as an effective approach for distinguishing competing interactions in quantum magnets.
Strongly Correlated Electrons (cond-mat.str-el)
Physical Review B (Letter) 113, L020404 (2026)
Cooperative concurrence of 4f and 3d flat bands in kagome heavy-fermion metal YbCr6Ge6
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-01-12 20:00 EST
Wenxin Lv, Pengcheng Ma, Tianqi Wang, Shangjie Tian, Ying Ma, Shouguo Wang, Xiao Zhang, Zhonghao Liu, Hechang Lei
Flat-band (FB) systems originating from special lattice geometry like in kagome metals as well as localized orbitals in the materials such as heavy-fermion (HF) compounds have induced intensive interest due to their band topology and strong electron correlation effects, leading to emergent quantum states of matter. However, the question of how these two distinct FBs coexist and interact remains unsettled. Here, we report that YbCr6Ge6 hosting both Cr-kagome lattice and Yb-4f electrons exhibits HF behaviors and a robust antiferromagnetic ground state with transition temperature TN = 3 K, significantly higher than other similar kagome metals with Yb ions. Angle-resolved photoemission spectroscopy measurements reveal the coexistence of FBs originating from both Cr-kagome lattice and localized Yb-4f electrons near Fermi energy level EF. More importantly, the clear spectroscopic signatures of a hybridization of Yb-4f FB with kagome-lattice-derived conduction bands and the high density of states of Cr-kagome FB near EF provide the underlying microscopic mechanisms of HF behaviors and enhanced antiferromagnetism in YbCr6Ge6. Our findings demonstrate that the novel kagome HF metals can not only host the cooperative coexistence of two different types of FBs, but also provide a paradigm material platform to explore the exotic correlated topological quantum phenomena.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
23 pages, 4 figures
On the Feasibility of Extreme Heating Rates in SEM using MEMS Heater Platforms
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-01-12 20:00 EST
C. Koenig, P. Mayr, J.R. Jinschek, A. Bastos Fanta
Understanding microstructural evolution under extreme thermal conditions is essential for advancing metal additive manufacturing (AM). This work demonstrates the feasibility of employing micro-electro-mechanical system (MEMS) heating platforms for in-situ scanning electron microscopy (SEM) characterization of bulk-like samples during rapid thermal cycling. Using electron backscatter diffraction (EBSD), we tracked the ferrite-to-austenite phase transformation in a pure iron specimen and confirmed that the sample surface temperature closely follows the MEMS temperature setpoint within device accuracy. Under vacuum conditions, stable heating and cooling rates of up to 1000 C/s were achieved with minimal power input and without compromising EBSD pattern quality. These findings establish MEMS-based heating as a robust approach for in-situ microstructural characterization of AM-relevant thermal processes in the SEM, enabling quantitative studies of thermally activated phenomena such as diffusion, phase transformations, and microstructural evolution under far-from-equilibrium conditions.
Materials Science (cond-mat.mtrl-sci)
Vorticity-Crystalline Order Coupling in Supersolids: Excitations and Re-entrant Phases
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-01-12 20:00 EST
Malte Schubert, Koushik Mukherjee, Philipp Stürmer, Stephanie Reimann
Rotation is a natural tool in ultracold gases to break time-reversal symmetry, yet its impact on the collective excitations of supersolids remains largely unexplored. We show theoretically that tuning the rotation frequency, (rather than the interparticle interactions), can trigger the superfluid-to-supersolid transition in Bose-Einstein condensates (dBECs). Computing excitation spectra in the presence of vortices and persistent currents, we uncover a vortex-driven de-softening mechanism whereby quantized vorticity elevates the gapless Goldstone mode to a finite-energy roton, restoring superfluidity. This effect results in re-entrant supersolid phases as a function of rotation frequency, revealing a fundamental coupling between topological defects and crystalline order.
Quantum Gases (cond-mat.quant-gas), Atomic Physics (physics.atom-ph)
9 pages, 5 figures
Topological origin of peak splitting in the structure factor of liquid water
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-01-12 20:00 EST
Zoé Faure Beaulieu, Volker L. Deringer, Fausto Martelli
The splitting of the principal peak in the structure factor of liquid water is commonly interpreted as evidence of a competition between two distinct local environments. Here, we show that this peak splitting arises from medium-range topological features of the hydrogen-bond network. Using atomistic simulations, we systematically decompose the structure factor into contributions from hydrogen-bonded rings of different sizes. We find that 5-8-membered rings, which dominate the network topology of liquid water at low temperatures, can directly explain the experimentally observed bimodal scattering signal. Among these, 5-membered rings are particularly persistent, maintaining distinct structural signatures even above room temperature. Our findings establish a direct link between the network topology of liquid water and experimentally accessible diffraction features, clarifying the microscopic basis of water’s behaviour and suggesting a broader conceptual framework for interpreting the anomalies in tetrahedral network liquids and glasses.
Soft Condensed Matter (cond-mat.soft), Chemical Physics (physics.chem-ph)
Learning microstructure in active matter
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-01-12 20:00 EST
Writu Dasgupta, Suvendu Mandal, Aritra K. Mukhopadhyay, Benno Liebchen
Understanding microstructure in terms of closed-form expressions is an open challenge in nonequilibrium statistical physics. We propose a simple and generic method that combines particle-resolved simulations, deep neural networks and symbolic regression to predict the pair-correlation function of passive and active particles. Our analytical closed-form results closely agree with Brownian dynamics simulations, even at relatively large packing fractions and for strong activity. The proposed method is broadly applicable, computationally efficient, and can be used to enhance the predictive power of nonequilibrium continuum theories and for designing pattern formation.
Soft Condensed Matter (cond-mat.soft), Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech)
13 pages, 11 figures
High-Energy Interlayer Exciton Ensembles in MoSe$_2$/WSe$_2$ Heterostructures by Laguerre-Gaussian Excitation
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-01-12 20:00 EST
Mirco Troue, Johannes Figueiredo, Gabriel Mittermair, Jonas Kiemle, Sebastian Loy, Hendrik Lambers, Takashi Taniguchi, Kenji Watanabe, Ursula Wurstbauer, Alexander W. Holleitner
We reveal the higher energetic luminescence part of interlayer exciton ensembles in MoSe$ _2$ /WSe$ _2$ heterostructures upon excitation by an optical Laguerre-Gaussian mode. The excitation is achieved with the help of a spatial light modulator giving rise to a ring-shaped distribution of interlayer excitons. A hyperspectral analysis of the exciton photoluminescence suggests that the excitation scheme allows the accumulation of high-energetic excitons in the rings’ center. We discuss the mechanisms leading to such a distribution, including exciton-exciton interaction, phase-space filling, and an incomplete thermalization.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
First-principles study of hydrogen diffusion in polycrystalline Nickel
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-01-12 20:00 EST
Bhanuj Jain, Alaa Olleak, Junyan He, Adarsh Chaurasia, Davide Di Stefano
Hydrogen embrittlement in metals is strongly governed by hydrogen diffusion and trapping, yet predicting these effects in polycrystalline systems remains challenging. This work introduces a multiscale modeling framework that links atomistic energetics to continuum-scale transport. Migration barriers for bulk and grain-boundary environments, obtained from first-principles calculations, are used in kinetic Monte Carlo simulations to compute anisotropic effective diffusivities. These diffusivities are then incorporated into finite element models of polycrystalline microstructures, explicitly accounting for grain-boundary character and connectivity. The approach captures both fast-path and trapping effects without relying on empirical parameters and reproduces experimental trends for nickel, including the dependence of effective diffusivity on grain size and boundary type. This methodology provides a physically grounded route for predicting hydrogen transport in engineering alloys and can be extended to other materials and defect types.
Materials Science (cond-mat.mtrl-sci)
16 pages, 13 figures
Phase-space networks and connectivity of the kagome antiferromagnet
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-01-12 20:00 EST
Brandon B. Le, Seung-Hun Lee, Gia-Wei Chern
We study the coplanar ground-state manifold of the kagome Heisenberg antiferromagnet using a phase-space network representation, in which nodes correspond to coplanar ground states and edges represent transitions generated by weathervane loop rotations. In the coplanar manifold, each configuration can be mapped to a three-coloring problem on the dual honeycomb lattice, where a weathervane mode corresponds to a closed loop of two alternating colors. By comparing networks that include all weathervane loops with networks restricted to elementary six-spin loops, we examine how energetic constraints shape phase-space structure. We find that connectivity distributions are sharply peaked in large systems, while restrictions to short loops reduce typical connectivity. Spectral properties further distinguish the two cases, with short-loop networks exhibiting Gaussian spectra and full networks displaying non-Gaussian features associated with correlated loop updates. Finally, a box-counting analysis reveals distinct fractal properties of the two networks, demonstrating how energetic constraints control the global geometry of configuration space. These results show that the hierarchy of weathervane loop rotations provides a direct link between microscopic constraints and emergent phase-space geometry in a frustrated magnet.
Statistical Mechanics (cond-mat.stat-mech), Strongly Correlated Electrons (cond-mat.str-el)
11 pages, 8 figures
Reverse segregation and self-organization in inclined chute flows of bidisperse granular mixtures
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-01-12 20:00 EST
Joseph M. Monti, Joel T. Clemmer, Ishan Srivastava, Leonardo E. Silbert, Gary S. Grest, Jeremy B. Lechman
In the usual segregation scenario for stable inclined chute flows of bidisperse mixtures of fine and coarse spherical particles, coarse particles rise toward the free surface, forming a coarse-rich region atop the flowing pile. Beyond a threshold coarse-to-fine diameter ratio of approximately 4, conversely, the weight of the coarse particles exceeds the segregation driving forces, causing individual coarse particles to sink within the pile and producing a reversed segregation state. However, an understanding of the collective evolution of the pile structure is still lacking when the particle diameter ratio exceeds 4 {\textit{and}} the coarse particle mass fraction is appreciable. To explore this broadly bidisperse limit, we perform discrete element method simulations considering mean particle diameter ratios of up to 8 and coarse particle mass fractions spanning 0.1 to 0.9. The steady-state flow profiles reveal several intriguing behaviors that depend on the diameter ratio and mass fraction. These include a previously identified transition from usual to reverse segregation and a newfound tendency to self-organize into alternating coarse- and fine-rich particle layers stacked along the shear gradient direction, with layer thickness dictated by the coarse particle diameter. A fuller understanding of segregation at this scale could pave the way for enhanced mixing or demixing techniques at the commercial scale.
Soft Condensed Matter (cond-mat.soft)
A Critical Examination of Active Learning Workflows in Materials Science
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-01-12 20:00 EST
Active learning (AL) plays a critical role in materials science, enabling applications such as the construction of machine-learning interatomic potentials for atomistic simulations and the operation of self-driving laboratories. Despite its widespread use, the reliability and effectiveness of AL workflows depend on implicit design assumptions that are rarely examined systematically. Here, we critically assess AL workflows deployed in materials science and investigate how key design choices, such as surrogate models, sampling strategies, uncertainty quantification and evaluation metrics, relate to their performance. By identifying common pitfalls and discussing practical mitigation strategies, we provide guidance to practitioners for the efficient design, assessment, and interpretation of AL workflows in materials science.
Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG)
Thermally Configurable Multi-Order Polar Skyrmions in Multiferroic Oxide Superlattices
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-01-12 20:00 EST
Kefan Liu, Yuhui Huang, Xiangwei Guo, Yongjun Wu, Juan Li, Zijian Hong
Polar topological textures in low-dimensional ferroelectrics have emerged as a versatile platform for high-density information storage and neuromorphic computing. While low-order topological states, such as vortices and skyrmions, have been extensively studied, high-order polar topological families remain largely unexplored due to their higher energy requirements and limited stabilization methods. Here, using a BiFeO3 (BFO)-based multiferroic superlattice as a model system, we demonstrate a thermal-modulation strategy that stabilizes multi-order polar skyrmions and enables reversible tuning of their topological order through phase-field simulations. It was found that temperature modulation drives the system from polar solitons through 1{\pi}-, 2{\pi}-, 3{\pi}-, and 4{\pi}-skyrmion states, with closed heating-cooling path analyses revealing the widest thermal stability window for 2{\pi}-skyrmions (up to 600 K). Leveraging this robustness, 2% Sm doping in BFO lowers the transition temperatures, enabling room-temperature stabilization of 2{\pi}-skyrmions. These findings enrich the fundamental understanding of multi-order polar topologies and establish a tunable strategy for realizing variable-order topological configurations in practical memory devices.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
5 figures, 19 pages
Evolution of the Berry curvature dipole in uniaxially strained bilayer graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-01-12 20:00 EST
Karel Cuypers, Robin Smeyers, Bert Jorissen, Lucian Covaci
While in pristine bilayer graphene the Berry curvature dipole (BCD), a necessary ingredient for the nonlinear anomalous Hall effect, is zero, uniaxial strain can give rise to finite BCD. We investigate this by using a tight-binding (TB) approach build on the Slater-Koster parameterization to capture lattice deformation effects often missed by continuum models. We demonstrate that the BCD’s evolution with strain and doping is highly sensitive to the choice in parameterization, particularly when including the longer range interlayer skew hoppings. Additionally, out-of-plane compression enhances the response by broadening the Dirac cones. These findings benchmark low-energy continuum models and highlight the necessity of realistic tight-binding models for accurately predicting strain-engineered Hall effects in bilayer graphene.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Mode-Selective Cloaking and Ghost Quantum Wells in Bilayer Graphene Transport
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-01-12 20:00 EST
Dan-Na Liu, Jun Zheng, Pierre A. Pantaleon
We study ballistic electron transport through electrostatic barriers in AB-stacked bilayer graphene within a full four-band framework. A mode-resolved analysis reveals how propagating and evanescent channels couple across electrostatic interfaces and how channel selectivity governs transport at normal incidence. We show that, even when decoupled channels remain inactive, perfect transmission can occur at discrete energies due to phase matching of a single internal mode within an individual barrier. This effect is interpreted as a ghost quantum well, namely an effective cavity formed by internal phase coherence inside the barrier, without true bound states and without restoring coupling to decoupled channels. For single- and double-barrier geometries, we derive compact analytical expressions for the transmission and identify the corresponding resonance conditions. Extending the analysis to multibarrier structures using a transfer-matrix approach, we demonstrate how perfect resonances driven by internal phase matching coexist with Fabry-Perot-like resonances arising from inter-barrier interference. Our results provide a unified, channel-resolved description of tunnelling suppression and resonance-assisted transport in bilayer graphene barrier systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
7 pages, 3 figures excluding appendixes. Comments are very welcome
Exact Volterra series for mean field dynamics
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-01-12 20:00 EST
We derive an exact Volterra series expansion for a mean field of an interacting particle system subject to a potential perturbation, expressing the Volterra expansion kernels in terms of the field’s response functions, to any order. Applying this formalism to the mean particle density of a simple fluid, we identify a form reminiscent of dynamical density functional theory, with, however, fundamental differences: A nonlocal mobility kernel appears, and forces derive from a functional of the {\it history} of mean density. The equilibrium density functional is shown to be recovered in the limit of slowly varying perturbation. We identify a freedom in deriving this expansion, which allows different forms of mobility kernels. These developments allow for a systematic improvement of established mean field formalisms.
Statistical Mechanics (cond-mat.stat-mech)
Comments are welcome
Slow mixing and emergent one-form symmetries in three-dimensional $\mathbb{Z}_2$ gauge theory
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-01-12 20:00 EST
Charles Stahl, Benedikt Placke, Vedika Khemani, Yaodong Li
Symmetry-breaking order at low temperatures is often accompanied by slow relaxation dynamics, due to diverging free-energy barriers arising from interfaces between different ordered states. Here, we extend this correspondence to classical topological order, where the ordered states are locally indistinguishable, so there is no notion of interfaces between them. We study the relaxation dynamics of the three-dimensional (3D) classical $ \mathbb{Z}2$ lattice gauge theory (LGT) as a canonical example. We prove a lower bound on the mixing time in the deconfined phase, $ t{\text{mix}} = \exp [\Omega(L)]$ , where L is the linear system size. This bound applies even in the presence of perturbations that explicitly break the one-form symmetry between different long-lived states. This perturbation destroys the energy barriers between ordered states, but we show that entropic effects nevertheless lead to diverging free-energy barriers at nonzero temperature. Our proof establishes the LGT as a robust finite-temperature classical memory. We further prove that entropic effects lead to an emergent one-form symmetry, via a notion that we make precise. We argue that the exponential mixing time follows from universal properties of the deconfined phase, and numerically corroborate this expectation by exploring mixing time scales at the Higgs and confinement transitions out of the deconfined phase. These transitions are found to exhibit markedly different dynamic scaling, even though both have the static critical exponents of the 3D Ising model. We expect this novel entropic mechanism for memory and emergent symmetry to also bring insight into self-correcting quantum memories.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
19+4 pages, 10+1 figures