CMP Journal 2025-06-26
Statistics
Nature Materials: 1
Nature Physics: 3
Physical Review Letters: 18
arXiv: 54
Nature Materials
Cytoplasmic anillin and Ect2 promote RhoA/myosin II-dependent confined migration and invasion
Original Paper | Cancer models | 2025-06-25 20:00 EDT
Avery T. Tran, Emily O. Wisniewski, Panagiotis Mistriotis, Konstantin Stoletov, Maria Parlani, Alice Amitrano, Brent Ifemembi, Se Jong Lee, Kaustav Bera, Yuqi Zhang, Soontorn Tuntithavornwat, Alexandros Afthinos, Alexander Kiepas, Bhawana Agarwal, Sanjiban Nath, John J. Jamieson, Yi Zuo, Daniel Habib, Pei-Hsun Wu, Stuart S. Martin, Sharon Gerecht, Luo Gu, John D. Lewis, Petr Kalab, Peter Friedl, Konstantinos Konstantopoulos
Cell migration in mechanically confined environments is a crucial step of metastatic cancer progression. Nonetheless, the molecular components and processes mediating such behaviour are still not fully understood. Here we demonstrate that a pool of the scaffolding protein anillin and its cofactor Ect2, which are both predominantly nuclear proteins and critical mediators of cytokinesis, is present in the cytoplasm of multiple interphase cell types that promote confined cell migration. Confined migration in biomimetic microfluidic models triggers the actomyosin-binding-dependent recruitment of anillin to the plasma membrane at the poles of migrating cells in a manner that scales with microenvironmental stiffness and confinement. The guanine nucleotide exchange activity of Ect2 is required for its RhoA-GTPase-mediated activation of myosin II at the cell poles, enhancing invasion, bleb-based migration and extravasation. Confinement-induced nuclear envelope rupture further amplifies this process due to the release of further anillin and Ect2 into the cytoplasm. Overall, these results show how Ect2 and anillin cooperate to mediate RhoA/ROCK/myosin II-dependent mechanoadaptation and invasive cancer progression.
Cancer models, Cell invasion
Nature Physics
Membraneless protocell confined by a heat flow
Original Paper | Biological physics | 2025-06-25 20:00 EDT
Alexander Floroni, Noël Yeh Martín, Thomas Matreux, Laura I. Weise, Sheref S. Mansy, Hannes Mutschler, Christof B. Mast, Dieter Braun
In living cells, a complex mixture of biomolecules is assembled within and across membranes. This non-equilibrium state is maintained by sophisticated protein machinery, which imports food molecules, removes waste products and orchestrates cell division. However, it remains unclear how this complex cellular machinery emerged and evolved. Here we show how the molecular contents of a cell can be coupled in a coordinated way to non-equilibrium heat flow. A temperature difference across a water-filled pore assembled the core components of a modern cell, which could then activate the gene expression. The mechanism arose from the interplay of convection and thermophoresis, both driven by the same heat source. The cellular machinery of protein synthesis from DNA via RNA was triggered as a direct result of the concentration of cell components. The same non-equilibrium setting continued to attract food molecules from an adjacent fluid stream, keeping the cellular molecules in a confined pocket protected against diffusion. Our results show how a simple non-equilibrium physical process can assemble the many different molecules of a cell and trigger its basic functions. The framework provides a membrane-free environment to bridge the long evolutionary times from an RNA world to a protein-based cell-like proto-metabolism.
Biological physics, Complex networks, Permeation and transport
Observation of the transverse Thomson effect
Original Paper | Condensed-matter physics | 2025-06-25 20:00 EDT
Atsushi Takahagi, Takamasa Hirai, Abdulkareem Alasli, Sang J. Park, Hosei Nagano, Ken-ichi Uchida
The Thomson effect refers to volumetric heating or cooling in a conductor when a charge current and a temperature gradient are applied in the same direction. Similarly, it is expected that a conductor will be heated or cooled when a charge current, a temperature gradient and a magnetic field are applied in orthogonal directions. This phenomenon, referred to as the transverse Thomson effect, has not been experimentally observed. Here we report the observation of this effect in a semimetallic Bi88Sb12 alloy with thermoelectric imaging. We can switch between heating or cooling by changing the direction of the magnetic field. Our experiments and analyses reveal the essential difference between the conventional and transverse Thomson effects. Whereas the former depends sorely on the temperature derivative of the Seebeck coefficient, the latter depends on the temperature derivative and the magnitude of the Nernst coefficient. The observation of the transverse Thomson effect provides a new concept for active thermal management technologies.
Condensed-matter physics, Spintronics, Thermoelectric devices and materials
Tunable interplay between light and heavy electrons in twisted trilayer graphene
Original Paper | Electronic properties and materials | 2025-06-25 20:00 EDT
Andrew T. Pierce, Yonglong Xie, Jeong Min Park, Zhuozhen Cai, Kenji Watanabe, Takashi Taniguchi, Pablo Jarillo-Herrero, Amir Yacoby
In systems with multiple energy bands, the interplay between electrons with different effective masses drives correlated phenomena that do not occur in single-band systems. Magic-angle twisted trilayer graphene is a tunable platform for exploring such effects, hosting both heavy electrons in its flat bands and delocalized light Dirac electrons in dispersive bands. Superconductivity in this system spans a wider range of phase space than moiré materials without dispersive bands, suggesting that interband interactions influence the stabilization of correlated phases. Here we investigate the interplay between the light and heavy electrons in magic-angle twisted trilayer graphene by performing local compressibility measurements with a scanning single-electron-transistor microscope. We establish that weak incompressibility features near several integer moiré band fillings host a finite population of light Dirac electrons at the Fermi level, despite a gap opening in the flat band sector. At higher magnetic field near charge neutrality, we find a phase transition sequence that is robust over nearly 10 μm but exhibits complex spatial dependence. Calculations establish that the Dirac sector can be viewed as flavour analogous to the spin and valley degrees of freedom.
Electronic properties and materials, Phase transitions and critical phenomena
Physical Review Letters
1D Spontaneous Symmetry Breaking in Thermal Equilibrium via Non-Hermitian Construction
Research article | Spontaneous symmetry breaking | 2025-06-25 06:00 EDT
Jia-Bao Wang, Zi-Hao Dong, and Yi Zhang
Spontaneous symmetry breaking generally circumvents one-dimensional systems with local interactions in thermal equilibrium. Here, we analyze a category of one-dimensional Hermitian models via local non-Hermitian constructions. Notably, spontaneous symmetry breaking and long-range order may emerge at finite temperatures in such systems under periodic boundary conditions, in sharp contrast to Hermitian constructions. We demonstrate clear numerical evidence, such as order parameters and specific heat, supporting phase diagrams with robust ordered phases. Non-Hermitian physics plays a vital role in prohibiting domain-wall proliferation and promoting spontaneous symmetry breaking. The fermions exhibit an exotic topological nature in their path-integral windings, which uphold nonzero integers—commonly a non-Hermitian signature—in the ordered phases, thus offering a novel and spontaneous origin for both symmetry breaking and non-Hermiticity.
Phys. Rev. Lett. 134, 250402 (2025)
Spontaneous symmetry breaking, Non-Hermitian systems
Exact Calculations of Coherent Information for Toric Codes under Decoherence: Identifying the Fundamental Error Threshold
Research article | Open quantum systems & decoherence | 2025-06-25 06:00 EDT
Jong Yeon Lee
The toric code is a canonical example of a topological error-correcting code. Two logical qubits stored within the toric code are robust against local decoherence, ensuring that these qubits can be faithfully retrieved as long as the error rate remains below a certain threshold. Recent studies have explored such a threshold behavior as an intrinsic information-theoretic transition, independent of the decoding protocol. These studies have shown that information-theoretic metrics, calculated using the Renyi (replica) approximation, demonstrate sharp transitions at a specific error rate. However, an exact analytic expression that avoids using the replica trick has not been shown, and the connection between the transition in information-theoretic capacity and the random bond Ising model (RBIM) has only been indirectly established. In this Letter, we present the first analytic expression for the coherent information of a decohered toric code, thereby establishing a rigorous connection between the fundamental error threshold and the criticality of the RBIM.
Phys. Rev. Lett. 134, 250601 (2025)
Open quantum systems & decoherence, Quantum error correction, Quantum information theory, Surface code quantum computing
Improved Limits on the Spin- and Velocity-Dependent Exotic Interaction in the Micrometer Range
Research article | Hypothetical particle physics models | 2025-06-25 06:00 EDT
Sumin Li, Wenbo Zhang, Rui Luo, Jinquan Liu, and Pengshun Luo
Searching for exotic interactions beyond the standard model of particle physics may solve some of the current puzzles in physics. Here, the authors experimentally explore a spin- and velocity-dependent exotic interaction between the nucleons in a gold sphere and the electrons in a spin source in the micrometer range. The microfabricated spin source provides periodically varying spin density of electrons, resulting in a periodic exotic field. A cantilever glued with a gold sphere is used to measure the force acting on the gold sphere by the spin source. The spin source is driven to oscillate, and then, the imaginary component of the signal is extracted at the 10th harmonic of the oscillation frequency, which effectively separates the exotic interaction from the spurious forces commonly present in such short-range measurements. No signal of the exotic interaction is observed, then, new limits on the coupling constant are set in the interaction range below $10\text{ }\text{ }\mathrm{\mu }\mathrm{m}$, with ${f}_{\perp }\le 2.2\times{}{10}^{- 9}$ at $2.1\text{ }\text{ }\mathrm{\mu }\mathrm{m}$.
Phys. Rev. Lett. 134, 251601 (2025)
Hypothetical particle physics models, Interactions & forces, Particle interactions, Hypothetical gauge bosons
Complex Liouville String
Conformal field theory | 2025-06-25 06:00 EDT
Scott Collier, Lorenz Eberhardt, Beatrix Mühlmann, and Victor A. Rodriguez
We introduce the complex Liouville string, a solvable string theory defined by coupling two Liouville theories with complex conjugate central charges $c\in 13+i\mathbb{R}$ on the world sheet. We compute its amplitudes from first principles and establish a duality with a double-scaled two-matrix integral. We also analyze general world sheet boundaries and nonperturbative effects in the genus expansion. By expressing the complex Liouville string as a 2D dilaton gravity theory with a sine potential, we show that it admits both ${\mathrm{AdS}}{2}$ and ${\mathrm{dS}}{2}$ vacua.
Phys. Rev. Lett. 134, 251602 (2025)
Conformal field theory, Path integrals, Quantum gravity, String dualities, Field & string theory models & techniques, Random matrix theory
Thrust Distribution in Electron-Positron Annihilation at Full Next-to-Next-to-Next-to-Leading-Logarithmic Accuracy Including Next-to-Next-to-Leading-Order Terms in QCD
Research article | Perturbative QCD | 2025-06-25 06:00 EDT
Ugo Giuseppe Aglietti, Giancarlo Ferrera, Wan-Li Ju, and Jiahao Miao
We consider the thrust ($T$) distribution in electron-positron (${e}^{+}{e}^{- }$) annihilation into hadrons and we perform the all-order resummation of the large logarithms of $1- T$ up to full next-to-next-to-next-to-leading logarithmic (${\mathrm{N}}^{3}\mathrm{LL}$) accuracy in QCD, also including the impact of next-order logarithmic corrections (${\mathrm{N}}^{4}\mathrm{LL}$). We consistently combine resummation with the known fixed-order results up to next-to-next-to-leading order (NNLO). All perturbative terms up to $\mathcal{O}({\alpha }{S}^{3})$ are included in our calculation, which, thanks to a unitarity constraint, exactly reproduces, after integration over $T$, the next-to-next-to-next-to-leading order (${\mathrm{N}}^{3}\mathrm{LO}$) result for the total cross section of ${e}^{+}{e}^{- }$ into hadrons. We perform resummation in the Laplace-conjugated space, which ensures the factorization of the kinematic momentum conservation constraint, and compare our results with those obtained using the resummation formalism in the physical ($T$) space. We find that the differences in the spectra obtained with the two different formalisms are sizable. Nonperturbative corrections are included using an analytic hadronization model, depending on two free parameters. Finally, we present a comparison of our spectra with experimental data at the $Z$-boson mass (${m}{Z}$) energy, which enables us to extract the value of the QCD coupling ${\alpha }{S}({m}{Z}^{2})=0.1181\pm{}0.0018$, fully consistent with the world average. We explicitly show that resumming Sudakov logarithms in Laplace-conjugated space and evaluating the inverse Laplace transform exactly is crucial in order to obtain an accurate determination of the QCD coupling.
Phys. Rev. Lett. 134, 251904 (2025)
Perturbative QCD, QCD phenomenology, Resummation methods
Jet Rates in Higgs Boson Decay at Third Order in QCD
Research article | Hadronic decays | 2025-06-25 06:00 EDT
Elliot Fox, Aude Gehrmann-De Ridder, Thomas Gehrmann, Nigel Glover, Matteo Marcoli, and Christian T. Preuss
We compute the production rates for two, three, four, and five jets in the hadronic decay of a Higgs boson in its two dominant decay modes to bottom quarks and gluons to third order in the QCD coupling constant. The five-, four-, and three-jet rates are obtained from a next-to-next-to-leading order calculation of Higgs decay to three jets, while the two-jet rate is inferred at next-to-next-to-next-to-leading order from the inclusive decay rate. Our results show distinct differences in the dependence of the jet rates on the jet resolution parameter between the two decay modes, supporting the aim of discriminating different Higgs boson decay channels via classic QCD observables.
Phys. Rev. Lett. 134, 251905 (2025)
Hadronic decays, Perturbative QCD, QCD phenomenology, Higgs bosons
Collisional Energy Transfer in the Highly Reactive ${\mathrm{OH}}^{+}$–${\mathrm{H}}_{2}$ System
Research article | Atomic & molecular collisions | 2025-06-25 06:00 EDT
Paul Pirlot Jankowiak and François Lique
Understanding the interplay between inelastic and reactive processes in low temperature molecular collisions is a true theoretical challenge. This study addresses this challenge by employing the statistical adiabatic channel model (SACM) to quantify the rotational excitation processes in the ${\mathrm{OH}}^{+}+{\mathrm{H}}{2}$ reactive system, such process being key in astrochemistry. The SACM approach demonstrates very good agreement with reduced dimensional close-coupling calculations in describing pure inelastic collisions in the low energy regime and satisfactory agreement with experimental measurement for treating reactive processes. Hence, the SACM approach can be considered as a good alternative to consider molecular collisions in reactive systems characterized by strongly bounded intermediate complexes, in absence of exact calculation in the low energy regime. Our findings reveal that reactive processes dominate the pure collisional excitation at all temperatures studied (5–300 K) by at least about one order of magnitude. This suggests a strong revision of the predicted abundance of ${\mathrm{OH}}^{+}$ in astrophysical environments since astrochemical models are presently significantly overestimating the impact of ${\mathrm{OH}}^{+}$ excitation induced by ${\mathrm{H}}{2}$ collisions.
Phys. Rev. Lett. 134, 253002 (2025)
Atomic & molecular collisions, Rotational states, Scattering theory
Ultralow Loss Torsion Micropendula for Chipscale Gravimetry
Research article | Force sensing | 2025-06-25 06:00 EDT
C. A. Condos, J. R. Pratt, J. Manley, A. R. Agrawal, S. Schlamminger, C. M. Pluchar, and D. J. Wilson
We explore a new class of chipscale torsion pendula formed by ${\text{Si}}{3}{\mathrm{N}}{4}$ nanoribbon suspensions. Owing to their unique heirarchy of gravitational, tensile, and elastic stiffness, the devices exhibit damping rates of $\sim 10\text{ }\text{ }\mathrm{\mu }\mathrm{Hz}$ and parametric gravity sensitivities near that of an ideal pendulum. The suspension nonlinearity can also be used to cancel the pendulum nonlinearity, paving the way toward fully isochronous, high $Q$ pendulum gravimeters. As a demonstration, we study a 0.1 mg, 32 Hz micropendulum with a damping rate of $16\text{ }\text{ }\mathrm{\mu }\mathrm{Hz}$, a thermal acceleration sensitivity of $2\times{}{10}^{- 9}{g}{0}/\sqrt{\mathrm{Hz}}\text{ }({g}{0}=9.8\text{ }\text{ }\mathrm{m}/{\mathrm{s}}^{2})$, and a parametric gravity sensitivity of $5\text{ }\text{ }\mathrm{Hz}/{g}{0}$. We record Allan deviations as low as $2.5\text{ }\text{ }\mathrm{\mu }\mathrm{Hz}$ at 100 seconds, corresponding to a bias stability of $5\times{}{10}^{- 7}{g}{0}$. We also demonstrate a 100-fold cancellation of the pendulum nonlinearity. In addition to inertial sensing, our devices are well suited to proposed searches for new physics exploiting low-loss micro- to milligram-scale mechanical oscillators.
Phys. Rev. Lett. 134, 253602 (2025)
Force sensing, Optomechanics, Micromechanical & nanomechanical oscillators, Micromechanical devices, Nano-oscillators, Nanomechanical devices, Noise measurements, Precision measurements, Weak measurements
Distinct Electronic Origins of Superconductivity and Nematicity in Fese
Research article | Superconductivity | 2025-06-25 06:00 EDT
Xueying Ma, Keyi Li, Shaoshuai Hou, Helin Mei, Yiwen Dong, Mingshu Tan, Mingtai Xie, Wei Ren, Xingdong Jiang, Zhiwei Li, Anmin Zhang, and Qingming Zhang
The complex interplay between superconductivity, nematicity, and magnetism in iron-based superconductors remains a significant challenge in understanding its high-temperature superconductivity. Despite that numerous experiments aim at revealing the underlying mechanisms for superconductivity and nematicity by varying multiple tuning parameters, the inherent entanglement of these parameters complicates the isolation of the fundamental factors that drive the transitions. Here, by introducing a novel hydrothermal treatment to FeSe, we are able to effectively reduce interstitial Fe without altering the crystal structure and magnetic properties. This treatment results in a notable increase in carrier density and mobility, simultaneously enhancing both superconducting and nematic transition temperatures. Combining our experimental results with previous investigations, we reveal distinct pocket-influenced mechanisms: superconducting order is primarily influenced by electron pockets, while nematic order is driven by hole pockets. The results demonstrate the independent mechanisms of superconductivity and nematicity in FeSe, offering new perspectives on high-temperature superconductivity.
Phys. Rev. Lett. 134, 256002 (2025)
Superconductivity, Transition temperature, Iron-based superconductors, Crystal growth, Density functional theory, Mössbauer spectroscopy, Raman spectroscopy, Resistivity measurements, X-ray diffraction, X-ray photoelectron spectroscopy
Medium-Range Order, Density Fluctuations, and Activated Relaxation in the Equilibrated Deep Glass Regime
Research article | Chemical Physics & Physical Chemistry | 2025-06-25 06:00 EDT
Baicheng Mei and Kenneth S. Schweizer
A successful microscopic theory of activated relaxation in metastable supercooled liquids is extended to the equilibrated deep glass regime. Surprisingly, the predicted power-law scaling connections of the dynamic barrier with diverse scalar order parameters (medium-range order correlation length, dimensionless compressibility, shear modulus) remain unchanged up to astronomically long timescales, despite a fundamental crossover of equilibrium thermodynamics and structure near the laboratory kinetic vitrification point. Quantitative tests against experiments on aged to equilibrium glass-forming liquids up to nearly 20 decades in time scale reveal good agreement. This conflicts with the idea of a crossover from super-Arrhenius to literal Arrhenius relaxation around the laboratory glass transition temperature, and supports the robustness of the theoretical idea that ultraslow dynamics is causally related to medium-range structural order. New avenues of experimental and theoretical research in the deep glass regime are suggested.
Phys. Rev. Lett. 134, 256101 (2025)
Chemical Physics & Physical Chemistry, Glass transition, Amorphous materials, Disordered systems, Glasses, Glassy systems
Hard and Soft Phase Slips in a Fabry-P'erot Quantum Hall Interferometer
Research article | Phase slips | 2025-06-25 06:00 EDT
N. L. Samuelson, L. A. Cohen, W. Wang, S. Blanch, T. Taniguchi, K. Watanabe, M. P. Zaletel, and A. F. Young
A new nonequilibrium picture for the behavior of quasiparticles in quantum Hall interferometers suggests that the dynamics of individual quasiparticles can be characterized by tracking the timescale over which they enter or exit the interferometer bulk.
Phys. Rev. Lett. 134, 256301 (2025)
Phase slips, Quantum Hall effect, Graphene, Van der Waals systems, Fabry-Pérot interferometry
Electrothermal Manipulation of Current-Induced Phase Transitions in Ferrimagnetic ${\mathrm{Mn}}{3}{\mathrm{Si}}{2}{\mathrm{Te}}_{6}$
Research article | Dynamical phase transitions | 2025-06-25 06:00 EDT
Jiaqi Fang, Jiawei Hu, Xintian Chen, Yaotian Liu, Zheng Yin, Zhe Ying, Yunhao Wang, Ziqiang Wang, Zhilin Li, Shiyu Zhu, Yang Xu, Sokrates T. Pantelides, and Hong-Jun Gao
Magnetic force microscopy is utilized to investigate current-induced phase transitions in ferrimagnetic materials and distinguish between current-induced quantum states and thermal contributions.
Phys. Rev. Lett. 134, 256302 (2025)
Dynamical phase transitions, Magnetic phase transitions, Phase transitions, Thermoelectric effects, Ferrimagnets, Magnetic force microscopy
Multiple Mechanisms for Emerging Conductance Plateaus in Fractional Quantum Hall States
Research article | Edge states | 2025-06-25 06:00 EDT
Sourav Manna, Ankur Das, Yuval Gefen, and Moshe Goldstein
Two-terminal conductance quantization in the context of quantum Hall (QH) physics is intimately related to the current carried by a discrete number of chiral edge modes. Upon pinching off a QH bar, one may engineer setups where some modes are fully transmitted (while the others are fully reflected), giving rise to the orthodox theory of quantized conductance plateaus. Here, we note that the observation of quantized plateaus does not uniquely indicate the underlying mechanism. Our Letter demonstrates explicitly that (i) such plateaus may be the manifestations of entirely different mechanisms; (ii) conductance measurements alone will not suffice to distinguish one from the other. We further show that measurements of shot noise (auto- and cross-correlation) at the plateau may discriminate among different mechanisms. While our observations apply to a broad class of QH states, we demonstrate their applicability employing a prototypical example: the bulk state of filling factor $\nu =2/3$. We present distinctly different scenarios that lead to a conductance plateau ${G}_{2\text{-terminal}}={e}^{2}/3h$ (observed previously) and likewise qualitatively different mechanisms leading to ${e}^{2}/2h$ (recently observed). We also predict the possibility of a new conductance plateau at $5{e}^{2}/9h$, following a nonorthodox scenario.
Phys. Rev. Lett. 134, 256503 (2025)
Edge states, Fractional quantum Hall effect, Shot noise, Two-dimensional electron gas
Topological Solitons in Square-Root Graphene Nanoribbons Controlled by Electric Fields
Research article | Topological phase transition | 2025-06-25 06:00 EDT
Haiyue Huang, Mamun Sarker, Percy Zahl, C. Stephen Hellberg, Jeremy Levy, Ioannis Petrides, Alexander Sinitskii, and Prineha Narang
Conjugational defects, also known as solitons, play an important role in the electronic, magnetic, and optical properties of materials. Understanding solitons can uncover intriguing physics and provide insights for designing quantum materials with tailored band structures and electronic properties. Here, we propose a framework to create and control solitons via topological phase transitions in a class of graphene nanoribbons (GNRs) called square-root GNRs, using a transverse electric field. To demonstrate the experimental feasibility, we design and synthesize a representative GNR with a bottom-up approach, with first-principles calculations revealing topological soliton states at the domain wall induced by the electric field. The framework introduced in this Letter can potentially enable direct manipulation of solitons and provide a platform to study them systematically.
Phys. Rev. Lett. 134, 256601 (2025)
Topological phase transition, Graphene, Nanoribbon, Topological insulators, Topological materials, First-principles calculations, Tight-binding model
Sliding Ferroelectrics Induced Hybrid-Order Topological Phase Transitions
Research article | Electric polarization | 2025-06-25 06:00 EDT
Ning-Jing Yang, Jian-Min Zhang, Xiao-Ping Li, Zeying Zhang, Zhi-Ming Yu, Zhigao Huang, and Yugui Yao
We propose ferroelectric layer sliding as a new approach to realize and manipulate topological quantum states in two-dimensional (2D) bilayer magnetic van der Waals materials. We show that stacking monolayer ferromagnetic topological states into layer-spin-locked bilayer antiferromagnetic structures, and introducing sliding ferroelectricity leads to asynchronous topological evolution of different layers (spins) owing to the existence of polarization potentials, thereby giving rise to rich layer-resolved topological phases. As a specific example, by means of a lattice model, we show that a bilayer magnetic 2D second order topological insulator (SOTI) reveals an unrecognized spin-hybrid-order topological insulator after undergoing ferroelectric sliding. Interestingly, in such a phase, the spin-up (top layer) and spin-down (bottom layer) channels exhibit first-order and second-order topological properties, respectively. Moreover, other topological phases such as the SOTI, quantum spin Hall insulator, quantum anomalous Hall insulator, and trivial insulator, can also emerge through changes in the parameters of the system; and the relevant topological indices are also discussed. In terms of materials, based on first principles calculations, we predict the material ${\mathrm{ScI}}_{2}$ can serve as an ideal platform to realize our proposal. Further, we predict that the anomalous Nernst effect of these several topological phases exhibits distinct differences, and therefore can be used as a signal for experimental probing.
Phys. Rev. Lett. 134, 256602 (2025)
Electric polarization, Topological phase transition, Topological phases of matter, Antiferromagnets, Ferroelectrics, Two-dimensional electron system, Tight-binding model
Observation of Extrinsic Topological Phases in Floquet Photonic Lattices
Research article | Topological effects in photonic systems | 2025-06-25 06:00 EDT
Rajesh Asapanna, Rabih El Sokhen, Albert F. Adiyatullin, Clément Hainaut, Pierre Delplace, Álvaro Gómez-León, and Alberto Amo
Discrete-step walks describe the dynamics of particles in a lattice subject to hopping or splitting events at discrete times. Despite being of primordial interest to the physics of quantum walks, the topological properties arising from their discrete-step nature have been hardly explored. Here we report the observation of topological phases unique to discrete-step walks. We use light pulses in a double-fiber ring setup whose dynamics maps into a two-dimensional lattice subject to discrete splitting events. We show that the number of edge states is not simply described by the bulk invariants of the lattice (i.e., the Chern number and the Floquet winding number) as would be the case in static lattices and in lattices subject to smooth modulations. The number of edge states is also determined by a topological invariant associated to the discrete-step unitary operators acting at the edges of the lattice. This situation goes beyond the usual bulk-edge correspondence and allows manipulating the number of edge states without the need to go through a gap closing transition. Our Letter opens new perspectives for the engineering of topological modes for particles subject to quantum walks.
Phys. Rev. Lett. 134, 256603 (2025)
Topological effects in photonic systems, Topological phases of matter, Floquet systems, Optical techniques
Magnetoelastic Dynamics of the Spin Jahn-Teller Transition in ${\text{CoTi}}{2}{\mathrm{O}}{5}$
Research article | Frustrated magnetism | 2025-06-25 06:00 EDT
K. Guratinder, R. D. Johnson, D. Prabhakaran, R. A. Taylor, F. Lang, S. J. Blundell, L. S. Taran, S. V. Streltsov, T. J. Williams, S. R. Giblin, T. Fennell, K. Schmalzl, and C. Stock
Even though there are no observable structural signatures in the spin-Jahn Teller transition in CoTi2O5, a dynamical signature in the acoustics could indicate that cooperative magnetoelastic fluctuations drive the transition.
Phys. Rev. Lett. 134, 256702 (2025)
Frustrated magnetism, Spin dynamics, Spin-phonon coupling
Atomiclike Selection Rules in Free Electron Scattering
Research article | Chirality | 2025-06-25 06:00 EDT
Simon Garrigou and Hugo Lourenço-Martins
Phase-shaped electron energy-loss spectroscopy (PSEELS) measures the scattering probability of structured free electron beams by a target. Over the last decade, it was shown that this scheme can be employed to emulate polarized optical spectroscopies with electrons, and therefore to transpose macroscopic optical concepts—such as dichroism—down to the deep subwavelength scale. In this Letter, we theoretically demonstrate that PSEELS can, in fact, go way further than mimicking optics and enables to map a plethora of so far inaccessible nano-optical quantities such as the electric quadrupolar momentum.
Phys. Rev. Lett. 134, 256902 (2025)
Chirality, Light-matter interaction, Near-field optics, Quantum optics, Electron microscopy, Spectroscopy
arXiv
Pair density modulation from glide symmetry breaking and nematic superconductivity
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-26 20:00 EDT
Michał Papaj, Lingyuan Kong, Stevan Nadj-Perge, Patrick A. Lee
Pair density modulation is a superconducting state, recently observed in exfoliated iron-based superconductor flakes, in which the superconducting gap oscillates strongly with the same periodicity as the underlying crystalline lattice. We propose a microscopic model that explains this modulation through a combination of glide-mirror symmetry breaking and the emergence of nematic superconductivity. The first ingredient results in a sublattice texture on the Fermi surface, which is aligned with the anisotropic superconducting gap of the nematic $ s_\pm+d$ state. This gives rise to distinctive gap maxima and minima located on the two inequivalent iron sublattices while still being a zero-momentum pairing state. We discuss how further investigation of such modulations can give insight into the nature of the superconducting pairing, such as the signs of the order parameters and visualization of a phase transition to a mixed two-component state using local probes.
Superconductivity (cond-mat.supr-con)
7+4 pages, 4+3 figures
Geometrically Frustrated Quadrupoles on the Pyrochlore Lattice and Generalized Spin Liquids
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-26 20:00 EDT
Kristian Tyn Kai Chung, Sylvain Petit, Julien Robert, Paul McClarty
As an instance of geometrical frustration with non-magnetic degrees of freedom, we explore the physics of local spin $ S\geq 1$ moments on the pyrochlore lattice that interact via pure quadrupolar couplings. In the presence of spin-orbit coupling, there are nine allowed couplings between nearest neighbor quadrupoles. We determine the semi-classical phases and survey the phase diagram of the model. One may view the Hamiltonian as being composed of two copies of the well-studied dipolar model with couplings between the copies, and we find that each easy-plane dipolar phase has two quadrupolar counterparts. As geometrical frustration is important over broad swathes of the parameter space, there are many classical quadrupolar liquids and regions with order-by-disorder selection of discrete states. Order-by-disorder with quadrupoles admits cubic terms in the Landau theory whose effects appear in Monte Carlo simulations and flavor wave calculations for fixed spin $ S$ . We showcase a number of examples of quadrupolar spin liquids, including one realizing a rank-3 symmetric tensor gauge theory exhibiting 6-fold pinch point singularities. We discuss remarkable differences between the quadrupolar physics of different spin quantum number. We also discuss connections to the non-Kramers rare earth pyrochlore materials.
Strongly Correlated Electrons (cond-mat.str-el)
36 pages, 16 figures, 2 tables
Topological Phase Transition under Infinite Randomness
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-06-26 20:00 EDT
In clean and weakly disordered systems, topological and trivial phases having a finite bulk energy gap can transit to each other via a quantum critical point. In presence of strong disorder, both the nature of the phases and the associated criticality can fundamentally change. Here we investigate topological properties of a strongly disordered fermionic chain where the bond couplings are drawn from normal probability distributions which are defined by characteristic standard deviations. Using numerical strong disorder renormalization group methods along with analytical techniques, we show that the competition between fluctuation scales renders both the trivial and topological phases gapless with Griffiths like rare regions. Moreover, the transition between these phases is solely governed by the fluctuation scales, rather than the means, rendering the critical behavior to be determined by an infinite randomness fixed point with an irrational central charge. Our work points to a host of novel topological phases and atypical topological phase transitions which can be realized in systems under strong disorder.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech), Strongly Correlated Electrons (cond-mat.str-el)
6+5 pages, 5+6 figures
Error-resilient Reversal of Quantum Chaotic Dynamics Enabled by Scramblons
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-26 20:00 EDT
Yu-Chen Li, Tian-Gang Zhou, Shengyu Zhang, Ze Wu, Liqiang Zhao, Haochuan Yin, Xiaoxue An, Hui Zhai, Pengfei Zhang, Xinhua Peng
The emergence of the arrow of time in quantum many-body systems stems from the inherent tendency of Hamiltonian evolution to scramble quantum information and increase entanglement. While, in principle, one might counteract this temporal directionality by engineering a perfectly inverted Hamiltonian to reverse entanglement growth, such a scenario is fundamentally unstable because even minor imperfections in the backward evolution can be exponentially amplified, a hallmark of quantum many-body chaos. Therefore, successfully reversing quantum many-body dynamics demands a deep understanding of the underlying structure of quantum information scrambling and chaotic dynamics. Here, by using solid-state nuclear magnetic resonance on a macroscopic ensemble of randomly interacting spins, we measure the out-of-time-ordered correlator (OTOC) and validate key predictions of scramblon theory, a universal theoretical framework for information scrambling. Crucially, this theory enables us to isolate and mitigate errors in the OTOC caused by imperfections in the backward evolution. As a result, this protocol uncovers the anticipated exponential behavior of quantum many-body chaos and extracts the quantum Lyapunov exponent in a many-body experimental system for the first time. Our results push the fundamental limits of dynamical reversibility of complex quantum systems, with implications for quantum simulation and metrology.
Strongly Correlated Electrons (cond-mat.str-el), Disordered Systems and Neural Networks (cond-mat.dis-nn), Quantum Gases (cond-mat.quant-gas), High Energy Physics - Theory (hep-th), Quantum Physics (quant-ph)
7 pages, 4 figures, supplementary material 13 pages, 5 figures, 4 tables
Zero Temperature Dynamics of Ising Systems on Hypercubes
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-26 20:00 EDT
Ruixin Chen, Jonathan Machta, Charles M. Newman, Daniel L. Stein
We study the zero-temperature Glauber dynamics of homogeneous Ising ferromagnets on hypercubes, as their dimension d varies. We investigate the asymptotic (d goes to infinity and time t goes to infinity) behavior of various quantities on hypercubes, such as the final magnetization, the probability for the system to enter a ground state, etc. Our numerical studies are carried out using a uniformly random initial state but with the constraint that the initial magnetization is zero. The final states can be divided into three categories: ground states, frozen states, and blinker states. We use the notion of a k-core to describe the geometry of the frozen states and give an exponential lower bound for the number of frozen states in terms of d. Blinker states – which exist only in even d – are final states containing at least one blinker (a permanently flipping spin). Blinker states can have rich local structures; we give explicit constructions for configurations that contain blinkers and prove that the lowest possible dimension for blinker configurations is d = 8. We also study the ‘Nature vs. Nurture’ problem on hypercubes, asking how much the final state depends on the information contained in the initial configuration, and how much depends on the realization of the dynamical evolution. Finally, we provide several conjectures and suggest some open problems based on the numerical results.
Statistical Mechanics (cond-mat.stat-mech)
Modeling Finite Deformations in Alloying Electrodes – A Closer Look at Cracks and Pores During Phase Transformation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-26 20:00 EDT
Delin Zhang, Yu-Cheng Lai, Kodi Thurber, Kai Smith, Johanna N. Weker, Sarah Tolbert, Ananya Renuka Balakrishna
Nanostructured electrodes with voids or interconnected pores accommodate large volume changes, shorten ion diffusion pathways, and enhance the structural reversibility of alloying electrodes. While these nanoporous features improve the performance of architected electrodes over bulk electrodes, they also act as geometric irregularities that localize and concentrate internal stresses. In this work, we investigate the hierarchical interplay between phase boundaries and nanoporous features at the microstructural scale and their collective role in mitigating chemo-mechanical failure at the engineering scale. Using Sb$ \to$ Li$ _2$ Sb$ \to$ Li$ _3$ Sb as a model system, we develop a continuum framework coupling lithium diffusion and reaction kinetics with the finite deformation of alloying electrodes. We analytically show that large volume changes in the Sb$ \rightarrow$ Li$ _2$ Sb transformation induce fracture, which nanoporous geometries can mitigate. Building on this, we develop a micromechanical model using a hyper-elastic neo-Hookean material law to predict the deformations accompanying the Li$ _2$ Sb$ \to$ Li$ _3$ Sb transformation. Our results reveal how diffusion and reaction kinetics shape phase boundary morphology, identify crack geometries likely to propagate, and show how carefully architected electrodes relieve stresses. These findings highlight critical design principles to optimize electrode lifespan and demonstrate a potential application of our continuum model as an electrode design tool.
Materials Science (cond-mat.mtrl-sci)
Boron Fullerenes: From Theoretical Predictions to Experimental Reality
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-26 20:00 EDT
We present a comprehensive first-principles investigation of boron fullerenes and two-dimensional boron sheets, unified under a coordination-based framework. By classifying over a dozen boron nanostructures, including B$ _{12}$ , B$ _{40}$ , B$ _{65}$ , B$ _{80}$ , and B$ _{92}$ , according to their local atomic environments (4-, 5-, and 6-fold coordination), we identify clear trends in structural stability, electronic properties, and magnetism. A universal energetic scaling relation $ E_c(n) = a/n^b + E_c^{sheet}$ (with $ b \approx 1$ ) captures the convergence of fullerene cohesive energies toward those of 2D boron phases. Notably, we establish one-to-one structural correspondences between select cages and experimentally accessible borophenes: B$ _{40}$ mirrors the $ \chi_3$ -sheet, B$ {65}$ the $ \beta{12}$ -sheet, B$ _{80}$ the $ \alpha$ -sheet, and B$ _{92}$ the $ bt$ -sheet. These clusters also exhibit large HOMO-LUMO gaps (e.g., $ E_g = 1.78$ eV for B$ _{40}$ , 1.14 eV for B$ _{92}$ ), contrasting with the metallicity of their 2D counterparts and, in the case of B$ _{65}$ , spontaneous spin polarization ($ M = 3 , \mu_B$ ). Our findings provide a predictive strategy for designing boron nanostructures by leveraging coordination fingerprints, and are further validated by the recent experimental synthesis of the B$ _{80}$ cage. This work bridges zero- and two-dimensional boron chemistry, offering a roadmap for the future synthesis and application of boron-based materials.
Materials Science (cond-mat.mtrl-sci)
6 pages, 3 figures, 1 table
Epitaxial Stabilization and Emergent Charge Order in Copper Selenide Thin Films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-26 20:00 EDT
B. M. Sharif (1), B. Theunissen (1), C. Westbrook (1), T. Steele (2), S. Choudhuri (1), R. Baumbach (1), S. Savrasov (2), D. Lederman (1) ((1) Department of Physics, University of California, Santa Cruz, Santa Cruz, CA, USA and Materials Science and Engineering Program, University of California, Santa Cruz, Santa Cruz, CA, USA (2) Department of Physics and Astronomy, University of California, Davis, Davis, CA, USA)
We demonstrate epitaxial growth of copper selenide (Cu$ _{2-x}$ Se) thin films in both cubic and rhombohedral phases, achieved via molecular beam epitaxy on Al$ _2$ O$ _3$ (001) substrates. Remarkably, the high-temperature cubic phase – which in bulk transforms into the rhombohedral structure below 400 K – is stabilized at room temperature and below, well outside its bulk equilibrium stability range. In the cubic phase films, temperature-dependent electrical transport reveals a pronounced, hysteretic resistivity peak near 140 K, accompanied by unit cell doubling along the [111] direction, as observed by x-ray diffraction, which are hallmarks of a charge density wave (CDW) transition. First-principles calculations show strong Fermi surface nesting in the cubic phase, consistent with the observed CDW instability. In contrast, the rhombohedral films exhibit suppressed nesting and no structural modulation. These results not only unambiguously identify a previously unreported CDW in Cu$ _{2-x}$ Se thin films, but also establish an epitaxial platform for tuning emergent electronic phases via strain and interface engineering.
Materials Science (cond-mat.mtrl-sci)
Algorithms for variational Monte Carlo calculations of fermion PEPS in the swap gates formulation
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-26 20:00 EDT
In recent years, the variational Monte Carlo (VMC) calculations of projected entangled pair states (PEPS) has emerged as a competitive method for computing the ground states of many-body quantum systems. This method is particularly important for fermion systems where sign problems are abundant. We derive and explain the algorithms for the VMC calculations of fermion PEPS in the swap gates formulation. It is the purpose of this paper to be as concise and precise as possible. Diagramatic tensor notation is used whenever possible to serve this purpose. As a separate result, we prove the detailed balance of sequential sampling of tensor networks.
Strongly Correlated Electrons (cond-mat.str-el)
Static friction of liquid marbles
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-26 20:00 EDT
Yui Takai, Kei Mukoyama, Pritam Kumar Roy, Guillaume Lagubeau, David Quéré, Samuel Poincloux, Timothée Mouterde
Liquid marbles, droplets coated with a granular layer, are highly mobile as particles prevent capillary adhesion with the substrate. Yet, they exhibit static friction due to their granular shell, which resists rolling until it yields. This friction depends on the shell geometry and increases exponentially with grain density, indicating a logistic dependence of interparticle compressive forces on surface coverage, confirmed by yielding measurements in granular rafts. These results reveal the shell’s dual role, and establish liquid marbles as a model system for probing granular raft mechanics.
Soft Condensed Matter (cond-mat.soft), Fluid Dynamics (physics.flu-dyn)
Carbon Nitride: Physical properties and Applications
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-26 20:00 EDT
Shilpi Kumari, Soubhagyam sharma, Manisha Kumari, Manish Kumar Singh, Rakesh K. Prasad, Kwang-geol Lee, Dilip K. Singh
Graphitic carbon nitride has emerged as a versatile, metal-free semiconductor with applications spanning over broad range of domains encompassing energy storage, environmental remediation and sensing. Despite significant progress in recent years, there remains a lack of comprehensive discussion on the graphitic carbon nitride’s evolving role in next-generation technologies and the engineering strategies needed to overcome existing challenges. In this review article, the critical assessment of the physicochemical properties of graphitic carbon nitride which holds potential to enable its function across diverse applications has been elucidated. Current advances in doping, heterojunction formation and composite engineering that enhances its catalytic and electronic performance has been summarized. The article also presents future research directions to unlock the full potential of graphitic carbon nitride as a useful material in sustainable and intelligent systems.
Materials Science (cond-mat.mtrl-sci)
Strong thermoelectric response of nanoconfined weak electrolytes
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-26 20:00 EDT
When dissolved, weak electrolytes only partially dissociate into ions in a temperature-dependent process. We show herein that such incomplete dissociation yields an enormous thermoelectric response in an electrolyte-filled nanochannel along which a temperature gradient is applied. For this purpose, an extended version of the Nernst-Planck equations is developed that takes into account the temperature-dependent dissociation-association equilibrium. The results indicate that in this way, Seebeck coefficients can be achieved that outperform all previously reported values.
Soft Condensed Matter (cond-mat.soft), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
25 pages, 4 figures
Quantum dot energy levels in bilayer graphene: Exact and approximate study
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-26 20:00 EDT
In bilayer graphene the exact energy levels of quantum dots can be derived from the four-component continuum Hamiltonian. Here, we study the quantum dot energy levels with approximate equations and compare them with the exact levels. The starting point of our approach is the four-component continuum model and the quantum dot is defined by a continuous potential well in a uniform magnetic field. Using some simple arguments we demonstrate realistic regimes where approximate quantum dot equations can be derived. Interestingly these approximate equations can be solved semi-analytically, in the same context as a single-component Schrödinger equation. The approximate equations provide valuable insight into the physics with minimal numerical effort compared with the four-component quantum dot model. We show that the approximate quantum dot energy levels agree very well with the exact levels in a broad range of parameters and find realistic regimes where the relative error is vanishingly small.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Highly anisotropic spin transport in ultrathin black phosphorus
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-26 20:00 EDT
Luke Cording, Jiawei Liu, Jun You Tan, Kenji Watanabe, Takashi Taniguchi, Ahmet Avsar, Barbaros Özyilmaz
In anisotropic crystals, the direction-dependent effective mass of carriers can have a profound impact on spin transport dynamics. The puckered crystal structure of black phosphorus (BP) leads to direction-dependent charge transport and optical response, suggesting that it is an ideal system for studying anisotropic spin transport. To this end, we fabricate and characterize high mobility encapsulated ultrathin BP-based spin-valves in four-terminal geometry. Our measurements show that in-plane spin-lifetimes are strongly gate tunable and exceed one nanosecond. Through high out-of-plane magnetic fields, we observe a five-fold enhancement in the out-of-plane spin signal case compared to in-plane and estimate a colossal spin lifetime anisotropy of ~ 6. This finding is further confirmed by Oblique Hanle measurements. Additionally, we estimate an in-plane spin-lifetime anisotropy ratio of up to 1.8. Our observation of strongly anisotropic spin transport along three orthogonal axes in this pristine material could be exploited to realize directionally tunable spin transport.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
19 pages, 4 figures
Nat. Mater. 23, (2024) 479-485
Observation of Berry Curvature-Enhanced Anomalous Photo-Nernst Effect in Magnetic Weyl Semimetal
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-26 20:00 EDT
Zipu Fan, Jinying Yang, Yuchun Chen, Ning Zhao, Xiao Zhuo, Chang Xu, Dehong Yang, Jun Zhou, Jinluo Cheng, Enke Liu, Dong Sun
The anomalous Nernst effect is the thermoelectric counterpart of the anomalous Hall effect, which can emerge in magnetic materials or topological materials without magnetic field. Such effect is critical to both fundamental topological physics and various application fields, including energy harvesting, spintronics and optoelectronics. In this work, we observe the anomalous photo-Nernst effect, which use light excitation to generate temperature gradients for the thermoelectric response. Our experiments reveal a pronounced edge photocurrent response in magnetic Weyl semimetal Co3Sn2S2 under zero magnetic field, originating from the anomalous photo-Nernst effect. The pronounced photo-Nernst current benefits from the exceptional properties of Co3Sn2S2, including the large thermoelectric coefficient, topologically enhanced anomalous response of Weyl bands and the Shockley-Ramo nature of long-range photocurrent generation. Furthermore, by comparing the nominal anomalous Nernst coefficient under different wavelength excitations, we observe a clear enhancement in the mid-infrared region, originating from the topological contribution from the large Berry curvature of Weyl bands. Our results reveal the interplay among light, magnetism, and topological order in magnetic Weyl semimetals, which not only offers insights for fundamental physics but also advances potential applications in quantum devices.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Majorana zero modes are the edge modes?
New Submission | Other Condensed Matter (cond-mat.other) | 2025-06-26 20:00 EDT
Vijay Pathak, Vaishnav Mallya, Sujit Sarkar
Topological phases are typically characterised by a topological invariant: winding number, which indicates the number of zero modes expected in a given phase. However, the winding number alone does not capture the qualitative differences between the modes within the same topological phase. In this work, we present an analytical solution for the zero-energy modes across various regimes of the phase diagram; a result that, to our knowledge, has not been reported previously in the literature. Through this solution, we characterise edge modes coexisting in a single phase and systematically classify them based on their spatial behaviour. Our analysis also identifies parameter regions where one or both zero modes are perfectly localised at the system edges. Finite and infinite systems were compared based on their spatial characteristics of zero modes. In addition, we provide a detailed analytical treatment of the characteristic equation, demonstrating that its roots offer further insight into the nature of the topological phase transitions. The whole study is based on a one-dimensional quantum Ising chain with long range interactions.
Other Condensed Matter (cond-mat.other)
Feedback and suggestions are welcome
High mechanical strength Si anode synthesis with interlayer bonded expanded graphite structure for lithium-ion batteries
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-26 20:00 EDT
Wenhui Lai, Jong Hak Lee, Lu Shi, Yuqing Liu, Yanhui Pu, Yong Kang Ong, Carlos Limpo, Ting Xiong, Yifan Rao, Chorng Haur Sow, Barbaros Özyilmaz
Despite advancements in silicon-based anodes for high-capacity lithium-ion batteries, their widespread commercial adoption is still hindered by significant volume expansion during cycling, especially at high active mass loadings crucial for practical use. The root of these challenges lies in the mechanical instability of the material, which subsequently leads to the structural failure of the electrode. Here, we present a novel synthesis of a composite combining expanded graphite and silicon nanoparticles. This composite features a unique interlayer-bonded graphite structure, achieved through the application of a modified spark plasma sintering method. Notably, this innovative structure not only facilitates efficient ion and electron transport but also provides exceptional mechanical strength (Vickers hardness: up to 658 MPa, Young’s modulus: 11.6 GPa). This strength effectively accommodates silicon expansion, resulting in an impressive areal capacity of 2.9 mA h cm-2 (736 mA h g-1) and a steady cycle life (93% after 100 cycles). Such outstanding performance is paired with features appropriate for large-scale industrial production of silicon batteries, such as active mass loading of at least 3.9 mg cm-2, a high-tap density electrode material of 1.68 g cm-3 (secondary clusters: 1.12 g cm-3), and a production yield of up to 1 kg per day.
Materials Science (cond-mat.mtrl-sci)
48 pages, 6 main figures, 16 supporting figures
W. Lai, J. H. Lee, … B. Oezyilmaz, High mechanical strength Si anode synthesis with interlayer bonded expanded graphite structure for lithium-ion batteries, Journal of Energy Chemistry 93 (2024) 253-263
Crystallization of Chiral Active Brownian Particles at Low Densities
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-26 20:00 EDT
Kangeun Jeong, Yuta Kuroda, Yuki Asatani, Takeshi Kawasaki, Kunimasa Miyazaki
Chiral active matter is a variant of active matter systems in which the motion of the constituent particles violates mirror symmetry. In this letter, we simulate two-dimensional chiral Active Brownian Particles, the simplest chiral model in which each particle undergoes circular motion, and show that the system crystallizes at low densities well below the melting point of the equilibrium counterpart. Crystallization is only possible if the orbital radius is long enough to align the circulating particles, but short enough for neighboring particles to avoid collisions. Of course, the system must be driven sufficiently far from equilibrium, since chirality cannot affect thermodynamic properties in classical equilibrium systems. The fluid-crystal phase diagram shows a re-entrant melting transition as a function of the radius of the circles. We show that at least one of the two transitions follows the same two-step melting scenario as in equilibrium systems.
Soft Condensed Matter (cond-mat.soft)
7 pages, 5 figures
Lack-of-fit reduction in the path-integral formalism
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-26 20:00 EDT
Katerina Mlada, Michal Pavelka, Vaclav Klika
We present a reformulation of the lack-of-fit reduction in non-equilibrium thermodynamics using the path-integral formalism. The reformulation is based on the Onsager-Machlup variational principle, and it allows us to minimize the action while keeping only thermodynamically relevant solutions. The reduced evolution consists of a Hamiltonian vector field and a gradient flow. The reformulation is illustrated on the Kac-Zwanzig model, where we show how irreversibility emerges from purely Hamiltonian evolution by ignoring some degrees of freedom. We also show how to generalize the Fisher information matrix and Kullback-Leibler divergence between two probability distributions to the case when the two distributions are related by the principle of maximum entropy, even in the case when the entropy is not of Boltzmann-Gibbs type (for instance Tsallis-Havrda-Charvat).
Statistical Mechanics (cond-mat.stat-mech), Mathematical Physics (math-ph)
Interfacial reconstruction effects in insulating double perovskite Nd$_2$NiMnO$_6$/SrTiO$_3$ and Nd$_2$NiMnO$_6$/NdGaO$_3$ thin films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-26 20:00 EDT
Nandana Bhattacharya, Ranjan Kumar Patel, Siddharth Kumar, Prithwijit Mandal, Jyotirmay Maity, Christoph Klewe, Zhan Zhang, Hua Zhou, Srimanta Middey
Ferromagnetic insulating (FMI) double perovskite oxides (DPOs) $ A_2BB’$ O$ _6$ with near-room-temperature Curie temperatures are promising candidates for ambient-temperature spintronics applications. To realize their potential, epitaxial stabilization of DPO films and understanding the effect of multiple broken symmetries across the film/substrate interface are crucial. This study investigates ultrathin films of the FMI Nd$ _2$ NiMnO$ _6$ (NNMO) grown on SrTiO$ _3$ (STO) and NdGaO$ _3$ (NGO) substrates. By comparing growth on these substrates, we examine the influence of polarity and structural symmetry mismatches, which are absent in the NGO system. The interface exhibits immeasurable resistance in both cases. Using synchrotron X-ray diffraction, we show that films have three octahedral rotational domains because of the structural symmetry mismatch with the STO substrate. Furthermore, our coherent Bragg rod analysis of specular X-ray diffraction reveals a significant modification of the out-of-plane lattice parameter within a few unit cells at the film/substrate interface and the surface. This arises from polarity compensation and surface symmetry breaking, respectively. These structural alterations influence the Mn orbital symmetry, a dependence that we further confirm through X-ray linear dichroism measurements. Since the ferromagnetism in insulating DPOs is mediated by orbital-dependent superexchange interactions [Phys. Rev. Lett. 100, 186402 (2008)], our study provides a framework for understanding the evolution of magnetism in ultrathin geometry.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
22 pages, 5 figures
Phys. Rev. B 111, 235438 (2025)
Two-dimensional transition metal selenides family M2Se: A platform for superconductivity, band topology, and charge density waves
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-26 20:00 EDT
Shu-Xiang Qiao, Kai-Yue Jiang, Yu-Lin Han, Na Jiao, Ying-Jie Chen, Hong-Yan Lu, Ping Zhang
MXenes and MBenes, which are two-dimensional (2D) transition metal carbides/nitrides and borides, have been extensively studied for their impressive properties. Recently, we reported a family of transition metal sulfides MSene (M2S) with rich properties [Phys. Rev. B 111, L041404 (2025)], it is worth studying whether selenides with similar structure also have rich properties. In this work, through high-throughput screening, we present a novel family of 2D transition metal selenides, M2Se. In this family, there are fifty-eight candidate materials, of which ten are stable and metallic. Notably, eight exhibit superconductivity, among which four are superconducting topological metals. Besides, eight show charge density wave (CDW) behavior, among which five also exhibit antiferromagnetism. It is revealed that CDW originates from electron-phonon coupling rather than Fermi surface nesting. Moreover, strain can be applied to regulate the competition between CDW and superconductivity. Our findings reveal the rich properties of superconductivity, band topology, CDW, and magnetism in M2Se, providing a new platform for the controllable integration of multifunctional quantum states.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
10 pages, 5 figures
Staggered nonlinear spin generations in centrosymmetric altermagnets under electric current
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-26 20:00 EDT
Jie Zhang, Ruijing Fang, Zhichao Zhou, Xiao Li
Current-induced spin generations are of significant importance for electrically controllable magnetization. Due to symmetry constraints, linear spin generation is absent in centrosymmetric magnets and nonlinear contributions become crucial. However, nonlinear spin generations have few examples in centrosymmetric compensated magnets with opposite-spin sublattices, which hinders electric control of associated magnetization. Here, we study nonlinear spin generations in altermagnets with opposite-spin sublattices. In a square altermagnetic model, both staggered and uniform nonlinear spin generations appear at opposite-spin sublattices. They vary as the magnetization direction rotates, with emerging out-of-plane components that can be utilized in perpendicular magnetization switching of high-density storage devices. By first-principles calculations, out-of-plane, staggered nonlinear spin generations are found to be considerable in a typical altermagnet, Fe$ _2$ Se$ _2$ O monolayer. Our findings provide opportunities for electrically manipulating magnetization and designing energy-efficient magnetic devices based on compensated magnets.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
6 pages, 4 figures
Graphene structure modification under tritium exposure: 3H chemisorption dominates over defect formation by \b{eta}-radiation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-26 20:00 EDT
Alexandra Becker, Genrich Zeller, Holger Lippold, Ismail Eren, Lara Rkaya Müller, Paul Chekhonin, Agnieszka Beata Kuc, Magnus Schlösser, Cornelius Fischer
Potential structural modifications of graphene exposed to gaseous tritium are important for membrane-based hydrogen isotope separation. Such modifications cannot be explained by electron irradiation alone. Instead, tritiation, caused by the tritium radicals remaining after the decay, is the primary effect causing the modification of the graphene surface, as confirmed by confocal Raman spectroscopy. The effect of the interaction of tritium atoms with the graphene surface exceeds that of electron irradiation at the average energy of the beta particles (5.7 keV). Compared to previously investigated high electron doses in the absence of tritium, remarkably low concentrations of tritium already induce a significant amount of sp3- and vacancy-type defects at short exposure times. Our findings are supported by molecular dynamics simulations of graphene bombardment with tritium atoms. As a consequence, tritium saturation of graphene may alter its permeability for hydrogen isotopes, thus affecting potential applications.
Materials Science (cond-mat.mtrl-sci), High Energy Physics - Experiment (hep-ex)
Anomalous Bulk Current in Quantum Hall Systems with an Expanding Edge
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-26 20:00 EDT
Yuuki Sugiyama, Tokiro Numasawa
Understanding topological phases of matter is essential for advancing both the fundamental theory and practical applications of condensed matter physics. Recently, a theoretical framework for a quantum Hall system with an expanding edge state was proposed [Phys. Rev. D {\bf 105}, 105009 (2022)], revealing the existence of an energy flux analogous to Hawking radiation on the edge. Motivated by this work, we extend the analysis to a model of a $ (2+1)$ -dimensional spacetime that includes both the bulk and edge regions. Due to the presence of bulk and edges, we demonstrate that the covariant form of the gravitational anomaly appears on the edge via the anomaly-inflow mechanism. Then, we investigate the energy flux on the edge from the viewpoint of gravitational anomalies, such as covariant gravitational and Weyl anomalies. We also find that, due to the conservation of energy and momentum in the entire system, the presence of anomalous currents on the expanding edge induces non-trivial currents in the bulk originating from the expansion of the edge.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), General Relativity and Quantum Cosmology (gr-qc), High Energy Physics - Theory (hep-th)
19 pages, 9 figures
Computational study of geometry, electronic structure and low-lying excited states of linear T-graphene quantum dots
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-26 20:00 EDT
A few years ago, by means of first-principles calculations, Enyashin et al.(2011) proposed several novel monolayers of carbon containing rings other than hexagons. One of those monolayers containing tetragons and octagons was investigated later in detail by Liu et al.(2012) who called it T-graphene, and found that it exists both in strictly planar and buckled forms, with the planar structure being metallic in nature. Given the fact that Kotakoski et al.(2011) had already found experimental evidence of 1D carbon structures containing tetragons and octagons, we decided to investigate finite linear fragments of T-graphene, with the strictly planar structures, referred to as T-graphene quantum dots (TQDs). In order to avoid the dangling bonds in the finite T-graphene fragments, we considered the edges to be saturated by hydrogen atoms. We first optimized the geometries of the considered TQDs using a first-principles density-functional theory (DFT) methodology, followed by calculations of their linear optical absorption spectra using the time-dependent DFT (TDDFT) approach. Given the fact that strictly planar T-graphene structures will have $ \sigma$ -$ \pi$ separation with the $ \pi$ electrons near the Fermi level, we also parameterized an effective $ \pi$ -electron Hamiltonian for TQDs, similar to the Pariser-Parr-Pople model for $ \pi$ -conjugated molecules. We further used the effective Hamiltonian to perform high-order electron-correlated calculations using the configuration interaction (CI) approach to compute the optical absorption spectra of TQDs, and also their singlet-triplet gaps. The symmetry analysis reveals that TQDs are photoluminescent materials. Moreover, in all the TQDs HOMO-LUMO transition is optically forbidden, the optical gaps of these molecules are quite large, suggesting the intriguing possibility of the fission of a singlet optical exciton into several triplet excitons.
Materials Science (cond-mat.mtrl-sci)
main manuscript: 40 pages, 10 figures, 5 tables; Supporting information: 16 pages, 2 figures, 16 tables
J. Phys. Chem. Solids 207, 112912 (2025)
Thermal excitation of flexoelectricity in silicon
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-26 20:00 EDT
Lingtong Lv, Qianqian Ma, Kailu Wang, Xin Wen, Shengping Shen
Flexoelectricity, an electromechanical coupling between strain gradient and polarization, offers a promising dimension to enrich silicon-based devices. Although the flexoelectricity of silicon is known, some fundamental aspects remain ambiguous, such as the discrepancy between experimental results and theoretical predictions, the influence of doping concentration, and the role of the bandgap. Here, we measured the flexoelectricity of intrinsic and heavily doped Si over the temperature range of 223 -473 K. The flexoelectric coefficient is of 2.6 {\mu}C/m and barely varies with temperature in doped silicon, while in intrinsic silicon it varies by nearly two orders of magnitude from 15.2 nC/m to 1.8 {\mu}C/m as temperature increases. We show that their different temperature dependencies correspond to the temperature-insensitive donor ionization in doped silicon and the temperature-sensitive intrinsic excitation in intrinsic silicon, with the latter captured by a quantitative relationship between flexoelectricity, temperature and bandgap. Furthermore, similar experimental results on germanium (Ge) suggest the universality of this relationship in first-generation semiconductors. These findings would offer valuable reference for developing Si-based electromechanical devices, as well as understanding the strain-gradient effects on semiconductor band structures (flexoelectronics).
Materials Science (cond-mat.mtrl-sci)
Transport Evidence for Wigner Crystals in Monolayer MoTe2
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-26 20:00 EDT
Mingjie Zhang, Zhenyu Wang, Yifan Jiang, Yaotian Liu, Kenji Watanabe, Takashi Taniguchi, Song Liu, Shiming Lei, Yongqing Li, Yang Xu
The crystallization of charge carriers, dubbed the Wigner crystal, is anticipated at low densities in clean two-dimensional electronic systems (2DES). While there has been extensive investigation across diverse platforms, probing spontaneous charge and spin ordering is hindered by disorder effects and limited interaction energies. Here, we report transport evidence for Wigner crystals with antiferromagnetic exchange interactions in high-quality, hexagonal boron nitride encapsulated monolayer MoTe2, a system that achieves a large interaction parameter (r_s) at proper hole densities. A density-tuned metal-insulator transition (MIT) occurring at 3.1E10^11 cm-2 (corresponding to r_s~32) and pronounced nonlinear charge transport in the insulating regime at low temperatures signify the formation of Wigner crystals. Thermal melting of the crystalline phase is observed below approximately 2 K via temperature-dependent nonlinear transport. Magnetoresistance measurements further reveal a substantial enhancement of spin susceptibility as approaching the MIT. The temperature dependence of spin susceptibility in the Wigner crystal phase closely follows the Curie-Weiss law, with the extracted negative Weiss constant illustrating antiferromagnetic exchange interactions. Furthermore, we have found the system exhibits metallic-like differential resistivity under finite DC bias, possibly indicating the existence of a non-equilibrium coherent state in the depinning of Wigner crystals. Our observations establish monolayer MoTe2 as a promising platform for exploring magnetic and dynamic properties of Wigner crystals.
Strongly Correlated Electrons (cond-mat.str-el)
25 pages, 4 figures and 8 supplemental figures
Equilibrium Propagation for Periodic Dynamics
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-06-26 20:00 EDT
Equilibrium propagation provides an exact method to compute the gradient of a cost function from the response to external forcing. These algorithms, in conjunction with local updates to the system parameters, may enable mechanical and electronic systems to autonomously acquire complex functionality. We extend these methods to damped dynamical systems operating in the linear regime by introducing an effective action, whose extremum corresponds to the periodic steady state. The condition of applicability is that the response function is symmetric, which is fulfilled by damped Newtonian dynamics and RLC networks. We demonstrate the viability of our method in those systems and explore novel functionality such as classifying temporal sound signals. Our work opens the door to intelligent materials that process dynamical signals, enabling temporal computations, passive and active sensors, and materials that act as frequency-dependent filters.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Soft Condensed Matter (cond-mat.soft)
6 pages, 3 figures
Superconducting bistability in floating Al islands of hybrid Al/InAs nanowires
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-26 20:00 EDT
E.V. Shpagina, E.S. Tikhonov, D. Ruhstorfer, G. Koblmueller, V.S. Khrapai
We investigate a non-equilibrium aspect of the current-driven superconducting-normal phase transition in floating Al islands of epitaxial full-shell Al/InAs nanowires. Within a transition region discontinuous voltage jumps and hysteretic behaviour of the I-V characteristics are observed, associated with the destruction and recovery of the superconducting order parameter in the island. The strength of the two features varies strongly in different devices in a mutually correlated way and can be suppressed by a small magnetic field. Numerical calculation explains this behaviour in terms of a tiny non-equilibrium correction to the electronic energy distribution at low energies. The experiment demonstrates a critical failure of a two-temperature non-equilibrium model of the superconductor-normal transition in floating islands of hybrid nanowire devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
Beyond Constant-Temperature Reservoirs: A Stirling Cycle with Constant Heat-Generation Rate
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-26 20:00 EDT
Xinshu Xia, Hongbo Huang, Hui Dong
Conventional heat-engine models typically assume two heat reservoirs at fixed temperatures. In contrast, radioisotope power systems introduce a fundamentally different paradigm in which the hot sources supply heat at a constant generation rate rather than maintaining a constant temperature. We develop a theoretical framework for finite-time heat engines operating between constant heat-generation-rate hot sources and constant-temperature cold reservoirs. A universal proportion between average output power and efficiency is established, independent of the specific cycle configuration or working substance. As a representative case, we analyze a finite-time Stirling cycle employing a tailored control protocol that maintains the working substance at constant temperatures during the quasi-isothermal processes. An intrinsic oscillatory behavior emerges in the temperature dynamics of the hot source, reflecting the interplay between heat accumulation and release. We further quantify the long-term decline in engine performance resulting from radioactive decay and demonstrate its impact over the system’s operational lifespan. This work establishes a new theoretical prototype for heat engines and shall provide guidings for the analysis and design of radioisotope power systems.
Statistical Mechanics (cond-mat.stat-mech)
6 pages, 4 figures
Shape-determined kinetic pathways in two-dimensional solid-solid phase transitions
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-26 20:00 EDT
Ruijian Zhu, Yi Peng, Yanting Wang
Solid-solid phase transitions are ubiquitous in nature, but the kinetic pathway of anisotropic particle systems remains elusive, where the coupling between translational and rotational motions plays a critical role in various kinetic processes. Here we investigate this problem by molecular dynamics simulation for two-dimensional ball-stick polygon systems, where pentagon, hexagon, and octagon systems all undergo an isostructural solid-solid phase transition. During heating, the translational motion exhibits merely a homogeneous expansion, whereas the time evolution of body-orientation is shape-determined. The local defects of body-orientation self-organize into a vague stripe for pentagon, a random pattern for hexagon, while a distinct stripe for octagon. The underlying kinetic pathway of octagon satisfies the quasi-equilibrium assumption, while that of hexagon and pentagon is dominated by translational motion and by rotational motion, respectively. This diversity is originated from different kinetic coupling modes determined by the anisotropy of molecules, and can affect the phase transition rates. The reverse process in terms of cooling follows the same mechanism, but the kinetic pathways are more diverse attributed to the possible kinetic traps. Our findings not only promote the theoretical understanding of microscopic kinetics of solid-solid phase transitions but also provide direct guidance for the rational design of materials utilizing desired kinetic features.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
Multiscale modeling of hydrogen diffusion in iron considering the effect of dislocations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-26 20:00 EDT
Gonzalo Álvarez, Álvaro Ridruejo, Javier Segurado
Modeling hydrogen diffusion and its absorption in traps is a fundamental first step towards the understanding and prediction of hydrogen embrittlement. In this study, a multiscale approach which includes DFT simulations, OkMC, and phase-field dislocations, is developed to study the movement of hydrogen atoms in alpha-iron crystals containing dislocations. At the nanoscale the interaction energies of hydrogen on different sites of the iron lattice are studied using DFT. At the microscale, this information is used to feed a lattice object kinetic Monte Carlo code (OKMC) which aims to evolve the arrangement of a large set of hydrogen atoms into the iron lattice considering point defects and the presence of dislocations. At the continuum level, an array of dislocations is introduced using a phase-field approach to accurately consider their elastic fields and core regions. The OKMC model includes both the chemical energies of H and vacancies and the elastic interactions between these point defects and the dislocations. The elastic interaction is obtained by an FFT-based approach which allows a very efficient computation of the elastic microfields created by the defects in an anisotropic medium. The framework has been used to obtain the diffusivity tensor of hydrogen as a function of the external stress state, temperature, and the presence of dislocations. It has been found that dislocations strongly affect the diffusivity tensor by breaking its isotropy and reducing its value by the effect of the microstresses around the dislocations.
Materials Science (cond-mat.mtrl-sci)
32 pages, 6 figures, 6 tables
Interplay of magnetic ordering and charge transport in a distorted ScAl$_3$C$_3$-type GdZn$_3$As$_3$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-26 20:00 EDT
Zhiyu Zhou, Xiyu Chen, Jia-Yi Lu, Junchao Zhang, Xiong Luo, Guang-Han Cao, Shuai Dong, Zhi-Cheng Wang
We present the synthesis and characterization of GdZn$ _3$ As$ _3$ , a previously unreported variant of the $ RM_3X_3$ family ($ R$ = lanthanides; $ M$ = Zn, Cd; $ X$ = P, As), prepared in both single-crystal and polycrystalline forms. Unlike other $ RM_3X_3$ compounds that crystallize in undistorted hexagonal structures, GdZn$ _3$ As$ _3$ adopts a distorted ScAl$ _3$ C$ _3$ -type orthorhombic structure with $ Cmcm$ space group. Magnetic measurements demonstrate that GdZn$ _3$ As$ 3$ undergoes a ferromagnetic transition at the Curie temperature ($ T{\mathrm{C}}$ ) of 6.3~K, which is unique among known $ RM_3X_3$ materials. This magnetic transition is further confirmed by specific heat and electrical resistivity measurements. GdZn$ _3$ As$ 3$ displays metallic behavior with a pronounced resistivity peak near $ T{\mathrm{C}}$ , which is strongly suppressed by magnetic fields, leading to significant negative magnetoresistance. Hall effect measurements reveal a low carrier density and a clear nonlinear anomalous Hall effect in GdZn$ _3$ As$ 3$ . Furthermore, both specific heat and resistivity data suggest the presence of additional magnetic transition(s) below $ T{\mathrm{C}}$ , requiring further investigation. These results demonstrate that GdZn$ _3$ As$ _3$ possesses distinct structural, magnetic, and electronic transport properties within the $ RM_3X_3$ family, establishing it as an exceptional platform for investigating competing magnetic interactions in low-carrier-density rare-earth triangular-lattice systems.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Phonon spectra and vibrational heat capacity of quasi-one-dimensional structures formed by rare gas atoms on the surface of carbon nanotube bundles
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-26 20:00 EDT
E. V. Manzhelii (1), S. B. Feodosyev (1), I. A. Gospodarev (1) ((1) B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, Kharkiv, Ukraine)
The features of phonon spectra and their effect on the vibrational heat capacity of linear chains of inert gas atoms adsorbed onto a substrate, which is the surface of nanotubes bound to a nanobundle. The influence of the substrate results both in a shift of the lower limit of the chain spectrum from zero, and in mechanical stress in the chain (its extension or compression) also. It is shown that in the case of a compressed chain, the non-central interaction between atoms is negative (repulsive), it results in a shift of the lower boundary of the spectrum of transverse vibrations to low frequencies and to a shortening of the part of the specific heat temperature dependence in which this dependence is close to exponential. Heterogeneity of the nanobundle structure can cause a change in the distances between atoms of the chain. It is shown both and analytically and numerically, that as a result of it, discrete levels with frequencies both above and below the quasi-continuous spectrum band can appear in the phonon spectrum of the chain. The discrete levels with frequencies below the quasi-continuous spectrum band lead to a further shortening of the temperature interval at which the temperature dependence of the specific heat is close to the exponential one.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Other Condensed Matter (cond-mat.other)
17 pages 7 figures
Fiz. Nizk. Temp. 45, 40 (2019) [Low Temp. Phys. 45, 355 (2019)]
Conditions for thermoelectric power factor improvements upon band alignment in complex bandstructure materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-26 20:00 EDT
Saff E Awal Akhtar, Neophytos Neophytou
Band alignment (or band convergence) is a strategy suggested to provide improvements in the thermoelectric power factor (PF) of materials with complex bandstructures. The addition of more bands at the energy region that contributes to transport, can provide more conducting paths and could improve the electrical conductivity and PF of a material. However, this can lead to increased inter-valley scattering, which will tend to degrade the conductivity. Using the Boltzmann Transport Equation (BTE) and a multi-band model, we theoretically investigate the conditions under which band alignment can improve the PF. We show that PF improvements are realized when intra-band scattering between the aligned bands dominates over inter-band scattering, with larger improvements reached when a light-band is brought into alignment. In the more realistic scenario of intra-and inter-band scattering co-existence, we show that in the light band alignment case, possibilities of PF improvement are present even down to the level where the intra- and inter-band scattering are of similar strength. For heavy band alignment this tolerance is weaker, and weaker inter-band scattering is necessary to realize PF improvements. On the other hand, when inter-band scattering dominates, it is not possible to realize any PF improvements upon band alignment, irrespective of bringing a light or a heavy band into alignment. Overall, to realize PF improvements upon band alignment, the valleys that are brought into alignment need to be as electrically conducting as possible compared to the lower energy base valleys and interact as little as possible with those.
Materials Science (cond-mat.mtrl-sci)
Research article, and supporting information together
Scalable and Tunable In-Plane Ge/Si(001) Nanowires Grown by Molecular Beam Epitaxy
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-26 20:00 EDT
Jian-Huan Wang, Ming Ming, Ding-Ming Huang, Jie-Yin Zhang, Yi Luo, Bin-Xiao Fu, Yi-Xin Chu, Yuan Yao, Hongqi Xu, Jian-Jun Zhang
Germanium nanostructures offer significant potential in developing advanced integrated circuit and disruptive quantum technologies, yet achieving both scalability and high carrier mobility remains a challenge in materials science. Here, we report an original low-temperature epitaxial method for growth of site-controlled in-plane germanium nanowires with high hole mobility by molecular beam epitaxy. By reducing the growth temperature, we effectively suppress Si-Ge interdiffusion, ensuring pure germanium composition within the nanowires while preserving their high crystalline quality. The method employs pre-patterned ridges on strain-relaxed Si$ _{0.75}$ Ge$ _{0.25}$ /Si(001) substrates as tailored templates, enabling control over the position, length, spacing and cross-sectional shape of the nanowires. Electrical measurements of field-effect devices made from as-grown germanium nanowires show that the nanowires are of hole conduction with mobility exceeding 7000 cm$ ^{2}$ /Vs at 2-20 K. The method paves a way for fabrication of scalable germanium nanowire networks, providing a reliable platform for the developments of high-performance nanoelectronics and multi-qubit chips.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
14 pages, 5 figures
Visualizing intercalation effects in 2D materials using AFM based techniques
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-26 20:00 EDT
Karmen Kapustić, Cosme G. Ayani, Borna Pielić, Kateřina Plevová, Šimun Mandić, Iva Šrut Rakić
Intercalation of two dimensional materials, particularly transition metal dichalcogenides, is a noninvasive way to modify electronic, optical and structural properties of these materials. However, research of these atomic-scale phenomena usually relies on using Ultra High Vacuum techniques which is time consuming, expensive and spatially limited. Here we utilize Atomic Force Microscopy (AFM) based techniques to visualize local structural and electronic changes of the MoS2 on graphene on Ir(111), caused by sulfur intercalation. AFM topography reveals structural changes, while phase imaging and mechanical measurements show reduced Young’s modulus and adhesion. Kelvin Probe Force Microscopy highlights variations in surface potential and work function, aligning with intercalation signatures, while Photoinduced Force Microscopy detects enhanced optical response in intercalated regions. These results demonstrate the efficacy of AFM based techniques in mapping intercalation, offering insights into tailoring 2D materials electronic and optical properties. This work underscores the potential of AFM techniques for advanced material characterization and the development of 2D material applications.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Journal of Physical Chemistry Letters 2025, 16, 19, 4804
High-Frequency and Microwave Magnetic Properties of Ni0.5Zn0.5Fe2O4 Spinel Ferrite Ceramics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-26 20:00 EDT
M. Kempa, V. Bovtun, V. Kukhar, S. Solopan, A. Belous, O. Vyunov, Y. Yakymenko, S. Kamba
Magnetic properties of the Ni0.5Zn0.5Fe2O4 (NZF) spinel ferrite ceramics were studied over a broad frequency range (1 MHz - 50 GHz). Between 10 MHz and 2 GHz, strong temperature-dependent resonance-like magnetic permeability dispersion was observed and attributed to the magnetic domain-wall dynamics. It is responsible for the high magnetic losses, absorption and shielding ability of NZF, and provides high nonlinearity and tunability of the permeability under a weak magnetic field. The attenuation constant of NZF is comparable to those of dielectric-conductor composites and giant permittivity materials. In the microwave range (2-50 GHz), three magnetic excitations dependent on a weak magnetic field were revealed and related to magnons. The lowest-frequency magnon (<10 GHz) is attributed to the natural ferromagnetic resonance, two others are excited between 28 and 44 GHz. Interaction of the magnons and magneto-dielectric resonance modes with electromagnetic waves provides high absorption and shielding efficiency in the GHz range, including 5G and 6G communication frequencies.
Materials Science (cond-mat.mtrl-sci)
Journal of Alloys and Compounds 1036 (2025) 181675
Rabi oscillations with close-range quantum vortex states
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-06-26 20:00 EDT
Quantum vortices separated through distances much larger than their core size interact via their long-range velocity field. At smaller separations, however, the influence of the core’s compressibility strongly influences the vortex dynamics. Using the example of a compact ring of five vortices, it is shown that close-range effects lead to a new (slower) state of orbital motion which is not predicted by the usual long-range theory. This secondary state can be created starting from the usual orbital state by modulating the interaction strength to induce Rabi oscillations between the states.
Quantum Gases (cond-mat.quant-gas)
7 pages, 2 figures
Quantized and nonquantized Hall response in topological Hatsugai-Kohmoto systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-26 20:00 EDT
Thibaut Desort, Mark O. Goerbig, Corentin Morice
We explore the robustness of Hall conductivity quantization in several insulating systems, exhibiting one scenario where the quantization is not preserved. Specifically, we apply the Kubo formula to topological models with the Hatsugai-Kohmoto interaction. Starting from the many-body degeneracy induced by this interaction in the topological Kane-Mele model, we consider Zeeman fields to select specific states within the ground-state manifold that reveal a non-quantized Hall response, precisely for the case with a Zeeman field diagonal in the bands of the Kane-Mele model. From a physical point of view, this term may mimic a ferromagnetic order that arises naturally when couplings beyond the Hatsugai-Kohmoto interaction are taken into account.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
10 pages, 4 figures
Theoretical study on ambient pressure superconductivity in La$_3$Ni$_2$O$_7$ thin films : structural analysis, model construction, and robustness of $s\pm$-wave pairing
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-26 20:00 EDT
Kensei Ushio, Shu Kamiyama, Yuto Hoshi, Ryota Mizuno, Masayuki Ochi, Kazuhiko Kuroki, Hirofumi Sakakibara
We theoretically study ambient pressure superconductivity in thin films of La$ 3$ Ni$ 2$ O$ 7$ . We construct model Hamiltonians adopting the crystal structure theoretically determined by fixing the in-plane lattice constant to those substrates examined in the experiment. We also construct a model based on the experimentally determined lattice structure. To the models obtained, we apply the fluctuation exchange approximation, which takes into account the full momentum and frequency dependencies of the Green function and the pairing interaction. We find that the electronic structure, including the presence/absence of the so-called $ \gamma$ -pocket (the Fermi surface originating from the top of the $ d{3z^2-r^2}$ bonding band) depends on the crystal structure adopted and/or the presence/absence of $ +U$ correction in the band structure calculation. Nonetheless, $ s\pm$ -wave pairing symmetry remains robust regardless of these details in the band structure. The robustness of the $ s\pm$ -wave pairing mainly owes to the large sign changing superconducting gap function of the $ d{3z^2-r^2}$ bands around $ (k_x,k_y)=(0,0)$ and $ (k_x,k_y)=(\pi,\pi)$ , which originates from the finite energy spin fluctuations. On the other hand, $ T_c$ being halved from that of the pressurized bulk can only be understood by adopting the model with small $ |t\perp|$ derived from the experimentally determined crystal structure, at least within the present FLEX approach, although there may remain some other possibilities beyond this approach for the origin of the reduced $ T_c$ .
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
13 pages, 9 figures
A direct dispersive signature of Pauli spin blockade
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-26 20:00 EDT
Simon Svab, Rafael S. Eggli, Taras Patlatiuk, Miguel J. Carballido. Pierre Chevalier Kwon, Dominique A. Trüssel, Ang Li, Erik P.A.M. Bakkers, Andreas V. Kuhlmann, Dominik M. Zumbühl
Pauli Spin Blockade (PSB) is a key paradigm in semiconductor nanostructures and gives access to the spin physics. We report the direct observation of PSB with gate-dispersive reflectometry on double quantum dots with source-drain bias. The reservoir charge transitions are strongly modulated, turning on and off when entering and leaving the blockaded region, consistent with a simple model. Seen with holes in Ge and Si, the effects are enhanced with larger bias voltage and suppressed by magnetic field. This work lays the foundation for fast probing of spin physics and minimally invasive spin readout.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
5 pages + 4 pages supplement
High-temperature helical edge states in BiSbTeSe$_2$/graphene van der Waals heterostructure
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-26 20:00 EDT
Yoichi Tanabe, Ngoc Han Tu, Ming-Chun Jiang, Yi Ling Chiew, Mitsutaka Haruta, Kiyohiro Adachi, David Pomaranski, Ryo Ito, Yuya Shimazaki, Daisuke Hashizume, Xiuzhen Yu, Guang-Yu Guo, Ryotaro Arita, Michihisa Yamamoto
Van der Waals heterostructures have been used to tailor atomic layers into various artificial materials through interactions at heterointerfaces. The interplay between the band gap created by the band folding of the interfacial potential and the band inversion driven by enhanced spin-orbit interaction (SOI) through band hybridization enables us to realize a two-dimensional topological insulator (2D-TI). Here we report the realization of graphene 2D-TIs by epitaxial growth of three-dimensional topological insulator (3D-TI) BiSbTeSe$ _2$ ultrathin films on graphene. By increasing the BiSbTeSe$ _2$ thickness from 2 nm to 9 nm to enhance SOI on graphene, the electronic state is altered from the trivial Kekul$ {é}$ insulator to the 2D-TI. The nonlocal transport reveals the helical edge conduction which survives up to 200 K at maximum. Our graphene 2D-TI is stable, easy to make electrical contacts, and of high quality. It offers various applications including spin-current conversion and platforms for Majorana fermions in junctions to superconductors.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
31pages, 4 figures, and 7 supporting figures
Analytical solution of coupled self–consistency and linearised Usadel equations for the dirty finite–sized superconductor at critical temperature
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-26 20:00 EDT
In this manuscript we analytically investigate the linearised Usadel equation and the self–consistency equation, defining the critical temperature of the superconducting phase transition of a finite–sized superconductor in the dirty limit. This is a system of coupled differential and integral equations for the anomalous Green function and the order parameter of the superconductor. The formal solution of the system is found for the general case of the linearised boundary conditions, reducing the solution to the solution of an eigenvalue problem. The latter defines the critical temperature of the superconducting phase transition and the spatial distributions of the anomalous Green function and the order parameter.
Superconductivity (cond-mat.supr-con)
Micromagnetic structure of oxidized magnetite nanoparticles: sharp structural versus diffuse magnetic interface
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-26 20:00 EDT
Elizabeth M. Jefremovas, Michael P. Adams, Lucía Gandarias, Lourdes Marcano, Javier Alonso, Andreas Michels, Jonathan Leliaert
The oxidation of magnetite to maghemite is a naturally occurring process that leads to the degradation of the magnetic properties of magnetite nanoparticles. Despite being systematically observed with traditional macroscopic magnetization measurement techniques, a detailed understanding of this process at the microscale is still missing. In this study, we track the evolution of the magnetic structure of magnetite nanoparticles during their oxidation to maghemite through numerical micromagnetic simulations. To capture realistic interparticle effects, we incorporate dipolar interactions by modeling the nanoparticles arranged in chains. Our computational results are benchmarked against experimental data from magnetotactic bacteria, studied over a time scale of years. To resolve the magnetization at the interface between both oxide phases, we propose spin-polarized small-angle neutron scattering (SANS), an experimental technique capable of probing magnetization textures at nanometer length scales. By analyzing the pair-distance distribution function extracted from SANS, we identify distinct signatures of magnetic disorder. Specifically, our findings suggest that the magnetization from the non-oxidized core region varies smoothly across the (structurally sharp) interface into the oxidized shell. The existence of such a diffuse magnetic interface may account for the superior magnetic properties of partially oxidized magnetite nanoparticles compared to fully converted maghemite samples.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Supplementary Information available at this http URL uploaded with this submission
Anomalous Energy Injection in Turbulent Neutron Star Cores
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-06-26 20:00 EDT
Anirudh Sivakumar, Pankaj Kumar Mishra, Ahmad A. Hujeirat, Paulsamy Muruganandam
Neutron star glitches – sudden increases in rotational frequency – are thought to result from angular momentum transfer via quantized vortices in the superfluid core. Using a two-dimensional rotating atomic Bose-Einstein condensate with phenomenological damping and a pinning potential to mimic the crust, we model the dynamics underlying these events. Our simulations reveal a transient Kolmogorov-like turbulent cascade ($ k^{-5/3}$ ) that transitions to a Vinen-like scaling ($ k^{-1}$ ). We identify an anomalous secondary injection mechanism driven primarily by quantum pressure, which sustains turbulent fluctuations in pulsar glitches. By tuning the damping coefficient $ \gamma$ , we determine an optimal regime for energy transfer. These findings provide a robust analogy for neutron star glitch phenomena and offer new insights into turbulence in extreme astrophysical environments.
Quantum Gases (cond-mat.quant-gas), General Relativity and Quantum Cosmology (gr-qc)
6 pages, 6 figures
Direct Observation of Hot Spots in Ferroelectric Domain Wall Devices by Scanning Thermal Microscopy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-26 20:00 EDT
Lindsey R. Lynch, J. Marty Gregg, Amit Kumar, Kristina M. Holsgrove, Raymond G. P. McQuaid
Ferroelectric domain wall devices offer a promising route to low voltage, reconfigurable nanoelectronics by confining currents to nanoscale conducting interfaces within an insulating bulk. However, resistive heating due to domain wall conduction still remains unexplored. Here, we employ scanning thermal microscopy to directly image hot spots in thin-film lithium niobate domain wall devices. Piezoresponse force microscopy shows that the hot spots correlate with nanodomain structure and thermal mapping reveals surface temperature rises of up to ~ 20 K, levels that are unlikely to negatively affect device performance. This is due to the moderate conductivity of domain walls, their voltage-tunable erasure, and distributed current pathways, which inherently limit power dissipation and peak temperatures. Finite element electrothermal modelling indicates that domain walls behave as pseudo-planar heat sources, distinct from filament-based models. These findings highlight the potential for domain wall devices as an energy-efficient, thermally stable platform for emerging memory and logic applications.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Main text: 16 pages, 4 figures. Supporting Information: 9 pages, 8 figures
On the temperature of an active nematic
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-26 20:00 EDT
Jay Armas, Akash Jain, Ruben Lier
We employ a novel hydrodynamic framework for active matter coupled to an environment to study the local temperature of an active nematic, assuming proximity to thermal equilibrium. We show that, due to the mechanosensitivity of fuel consumption, linearized temperature correlations in a homogeneous active nematic steady state remain unaffected by activity. However, we demonstrate that local shearing and twisting cause a confined active nematic undergoing a spontaneous flow transition to develop a distinctive inhomogeneous temperature profile, serving as a thermal signature of activity.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech), High Energy Physics - Theory (hep-th)
Modeling phase transformations in Mn-rich disordered rocksalt cathodes with charge-informed machine-learning interatomic potentials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-26 20:00 EDT
Peichen Zhong, Bowen Deng, Shashwat Anand, Tara Mishra, Gerbrand Ceder
Mn-rich disordered rocksalt (DRX) cathode materials exhibit a phase transformation from a disordered to a partially disordered spinel-like structure ($ \delta$ -phase) during electrochemical cycling. In this computational study, we used charge-informed molecular dynamics with a fine-tuned CHGNet foundation potential to investigate the phase transformation in Li$ _{x}$ Mn$ _{0.8}$ Ti$ _{0.1}$ O$ _{1.9}$ F$ _{0.1}$ . Our results indicate that transition metal migration occurs and reorders to form the spinel-like ordering in an FCC anion framework. The transformed structure contains a higher concentration of non-transition metal (0-TM) face-sharing channels, which are known to improve Li transport kinetics. Analysis of the Mn valence distribution suggests that the appearance of tetrahedral Mn$ ^{2+}$ is a consequence of spinel-like ordering, rather than the trigger for cation migration as previously believed. Calculated equilibrium intercalation voltage profiles demonstrate that the $ \delta$ -phase, unlike the ordered spinel, exhibits solid-solution signatures during the 0-TM to Li$ _{\text{tet}}$ conversion reaction. A higher Li capacity is obtained than in the DRX phase. This study provides atomic insights into solid-state phase transformation and its relation to experimental electrochemistry, highlighting the potential of charge-informed machine learning interatomic potentials for understanding complex oxide materials.
Materials Science (cond-mat.mtrl-sci)
Depinning and activated motion of chiral self-propelled robots
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-26 20:00 EDT
Juan Pablo Carrillo-Mora, Adrià Garcés, Demian Levis
We study experimentally, numerically and analytically, the dynamics of a chiral active particle (cm-sized robots), pulled at a constant translational velocity. We show that the system can be mapped to a Brownian particle driven across a periodic potential landscape, and thus exhibits a rotational depinning transition in the noiseless limit, giving rise to a creep regime in the presence of rotational diffusion. We show that a simple model of chiral, self-aligning, active particles accurately describes such dynamics. The steady-state distribution and escape times from local potential barriers, corresponding to long-lived orientations of the particles, can be computed exactly within the model and is in excellent agreement with both experiments and particle-based simulations, with no fitting parameters. Our work thus consolidates such self-propelled robots as a model system for the study of chiral active matter, and highlights the interesting dynamics arising from the interplay between external and internal driving forces in the presence of a self-aligning torque.
Statistical Mechanics (cond-mat.stat-mech), Soft Condensed Matter (cond-mat.soft)
4 pages and 3 figures
Floquet operator dynamics and orthogonal polynomials on the unit circle
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-26 20:00 EDT
Operator spreading under stroboscopic time evolution due to a unitary is studied. An operator Krylov space is constructed and related to orthogonal polynomials on a unit circle (OPUC), as well as to the Krylov space of the edge operator of the Floquet transverse field Ising model with inhomogeneous couplings (ITFIM). The Verblunsky coefficients in the OPUC representation are related to the Krylov angles parameterizing the ITFIM. The relations between the OPUC and spectral functions are summarized and several applications are presented. These include derivation of analytic expressions for the OPUC for persistent $ m$ -periodic dynamics, and the numerical construction of the OPUC for autocorrelations of the homogeneous Floquet-Ising model as well as the $ Z_3$ clock model. The numerically obtained Krylov angles of the $ Z_3$ clock model with long-lived period tripled autocorrelations show a spatial periodicity of six, and this observation is used to develop an analytically solvable model for the ITFIM that mimics this behavior.
Strongly Correlated Electrons (cond-mat.str-el)
Tunable lower critical fractal dimension for a non-equilibrium phase transition
New Submission | Other Condensed Matter (cond-mat.other) | 2025-06-26 20:00 EDT
Mattheus Burkhard, Luca Giacomelli, Cristiano Ciuti
We theoretically investigate the role of spatial dimension and driving frequency in a non-equilibrium phase transition of a driven-dissipative interacting bosonic system. In this setting, spatial dimension is dictated by the shape of the external driving field. We consider both homogeneous driving configurations, which correspond to standard integer-dimensional systems, and fractal driving patterns, which give rise to a non-integer Hausdorff dimension for the spatial density. The onset of criticality is characterized by critical slowing down in the excited density dynamics as the system asymptotically approaches the steady state, signaling the closing of the Liouvillian frequency gap. We show that the lower critical dimension – below which the non-equilibrium phase transition ceases to occur – can be controlled continuously by the frequency detuning of the driving field.
Other Condensed Matter (cond-mat.other), Optics (physics.optics)
Reducing Self-Interaction Error in Transition-Metal Oxides with Different Exact-Exchange Fractions for Energy and Density
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-26 20:00 EDT
Harshan Reddy Gopidi, Ruiqi Zhang, Yanyong Wang, Abhirup Patra, Jianwei Sun, Adrienn Ruzsinszky, John P. Perdew, Pieremanuele Canepa
DFT is vital for materials discovery, and at the base of extensive molecular and materials databases, chemical reaction predictions, and machine learning potentials. The widespread use of DFT in chemistry and materials science aims for “chemical accuracy,” but this is limited by the unknown exchange and correlation (XC) functional. A meta-GGA, the restored regularized strongly constrained and appropriately normed, r r2SCAN XC functional, fulfils 17 exact constraints of the XC energy. r2SCAN still appears inadequate at predicting material properties of strongly correlated compounds. Inaccuracies of r2SCAN arise from functional and density-driven errors, linked to the self-interaction error. We introduce a new method, r2SCANY@r2SCANX, for simulating transition metal oxides accurately. r2SCANY@r2SCANX utilizes different fractions of exact exchange: X to set the electronic density, and Y to set the energy density functional approximation. r2SCANY@r2SCANX addresses functional-driven and density-driven inaccuracies. Using just one or two universal parameters, r2SCANY@r2SCANX enhances the r2SCAN predictions of the properties of 18 correlated oxides, outperforming the highly parameterized DFT+U method. The O2 overbinding in r2SCAN (~0.3 eV/O2) reduces to just ~0.03 eV/O$ _2$ with any X in r2SCAN10@r2SCANX. Uncertainties for oxide oxidation energies and magnetic moments are reduced by r2SCAN10@r2SCAN50, minimizing r2SCAN density-driven errors. The computationally efficient r2SCAN10@r2SCAN is nearly as accurate as the hybrid r2SCAN10 for oxidation energies. Thus, accurate energy differences can be achieved by rate-limiting self-consistent iterations and geometry optimizations with the efficient r2SCAN. Subsequently, expensive hybrid functionals can be applied in a fast-to-execute single post-self-consistent calculation, as in r2SCAN10@r2SCAN, which is 10 to 300 times faster than r2SCAN10.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el), Chemical Physics (physics.chem-ph), Computational Physics (physics.comp-ph)
Artificial Symmetry Breaking by Self-Interaction Error
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-26 20:00 EDT
Lin Hou, Cody Woods, Yanyong Wang, Jorge Vega Bazantes, Ruiqi Zhang, Shimin Zhang, Erik Alfredo Perez Caro, Yuan Ping, Timo Lebeda, Jianwei Sun
Symmetry is a cornerstone of quantum mechanics and materials theory, underpinning the classification of electronic states and the emergence of complex phenomena such as magnetism and superconductivity. While symmetry breaking in density functional theory can reveal strong electron correlation, it may also arise spuriously from self-interaction error (SIE), an intrinsic flaw in many approximate exchange-correlation functionals. In this work, we present clear evidence that SIE alone can induce artificial symmetry breaking, even in the absence of strong correlation. Using a family of one-electron, multi-nuclear-center systems ( \mathrm{H}^+{n \times \frac{+2}{n}}(R) ), we show that typical semilocal density functionals exhibit symmetry-breaking localization as system size increases, deviating from the exact, symmetry-preserving Hartree-Fock solution. We further demonstrate that this localization error contrasts with the well-known delocalization error of semilocal density functionals and design a semilocal density functional that avoids the artifact. Finally, we illustrate the real-world relevance of this effect in the \ch{Ti{Zn}v_O} defect in ZnO, where a semilocal density functional breaks the $ C_{3v}$ symmetry while a hybrid density functional preserves it. These findings highlight the need for improved functional design to prevent spurious symmetry breaking in both model and real materials.
Materials Science (cond-mat.mtrl-sci)