CMP Journal 2025-06-03
Statistics
Nature Materials: 1
Nature Nanotechnology: 1
Physical Review Letters: 3
Physical Review X: 1
arXiv: 100
Nature Materials
Symmetry-protected electronic metastability in an optically driven cuprate ladder
Original Paper | Electronic properties and materials | 2025-06-02 20:00 EDT
Hari Padma, Filippo Glerean, Sophia F. R. TenHuisen, Zecheng Shen, Haoxin Wang, Luogen Xu, Joshua D. Elliott, Christopher C. Homes, Elizabeth Skoropata, Hiroki Ueda, Biaolong Liu, Eugenio Paris, Arnau Romaguera, Byungjune Lee, Wei He, Yu Wang, Seng Huat Lee, Hyeongi Choi, Sang-Youn Park, Zhiqiang Mao, Matteo Calandra, Hoyoung Jang, Elia Razzoli, Mark P. M. Dean, Yao Wang, Matteo Mitrano
Optically excited quantum materials exhibit non-equilibrium states with remarkable emergent properties, but these phenomena are usually transient, decaying on picosecond timescales and limiting practical applications. Advancing the design and control of non-equilibrium phases requires the development of targeted strategies to achieve long-lived, metastable phases. Here we report the discovery of symmetry-protected electronic metastability in the model cuprate ladder Sr14Cu24O41. Using femtosecond resonant X-ray scattering and spectroscopy, we show that this metastability is driven by a transfer of holes from chain-like charge reservoirs into the ladders. This ultrafast charge redistribution arises from the optical dressing and activation of a hopping pathway that is forbidden by symmetry at equilibrium. Relaxation back to the ground state is, hence, suppressed after the pump coherence dissipates. Our findings highlight how dressing materials with electromagnetic fields can dynamically activate terms in the electronic Hamiltonian, and provide a rational design strategy for non-equilibrium phases of matter.
Electronic properties and materials, Magnetic properties and materials, X-rays
Nature Nanotechnology
In vivo transformations of positively charged nanoparticles alter the formation and function of RuBisCO photosynthetic protein corona
Original Paper | Analytical chemistry | 2025-06-02 20:00 EDT
Christopher Castillo, Su-Ji Jeon, Khoi Nguyen L. Hoang, Claire Alford, Erica Svendahl, Chaoyi Deng, Yi Wang, Yinhan Wang, Xingfei Wei, Rigoberto Hernandez, Jason C. White, Korin E. Wheeler, Catherine J. Murphy, Juan Pablo Giraldo
The impact of nanomaterial transformations on photosynthetic proteins remains largely unknown. We report positively charged iron oxide (Fe3O4) nanoparticles experience transformations in Arabidopsis thaliana plants in vivo that alter the formation and function of RuBisCO protein corona, a key carbon fixation enzyme. In vitro, negatively charged Fe3O4 nanoparticles impact the RuBisCO function but not their positively charged counterparts. Computational and in vitro proteomic analyses revealed that positively charged Fe3O4 nanoparticles preferentially bind to a RuBisCO small subunit that lacks active carboxylation sites. However, both positively and negatively charged nanoparticles decrease RuBisCO carboxylation activity after experiencing transformations in vivo by 3.0 and 1.7 times relative to the controls, respectively. The pH- and lipid-coating-dependent transformations that occur during nanoparticle transport across plant membranes enhance RuBisCO binding to positively charged nanoparticles affecting its distribution in chloroplasts. Elucidating the rules of how nanoparticle properties and transformations affect photosynthetic coronas is crucial for sustainable nano-enabled agriculture.
Analytical chemistry, Nanobiotechnology, Nanoscience and technology
Physical Review Letters
Ionization Energy of Metastable $^{3}\mathrm{He}$ (2 $^{3}{S}_{1}$) and the Alpha- and Helion-Particle Charge-Radius Difference from Precision Spectroscopy of the $np$ Rydberg Series
Research article | Atomic & molecular structure | 2025-06-02 06:00 EDT
Gloria Clausen and Frédéric Merkt
New physics may explain discrepant values for the ionization energy of a metastable state of helium.
Phys. Rev. Lett. 134, 223001 (2025)
Atomic & molecular structure, Atomic spectra, Electronic excitation & ionization, Electronic structure of atoms & molecules, Atomic & molecular beams, Rydberg atoms & molecules, Atomic Properties, Optical spectroscopy
Limits on Anomalous Spin-Spin Interactions Using Noble-Gas Nuclear Magnetic Resonance
Research article | Atomic & molecular processes in external fields | 2025-06-02 06:00 EDT
Haowen Su, Shiju Hu, Yang Ding, Yuanhong Wang, Min Jiang, and Xinhua Peng
Numerous theories beyond the standard model of particle physics propose the existence of ultralight hypothetical bosons, which are prominent dark-matter candidates. One of the most promising approaches to search for these bosons is through precision measurements. The basic principle is to measure energy shifts of standard-model particles induced by hypothetical bosons with ultrahigh energy resolution. Here we develop a sensitive magnetometer based on noble-gas nuclear magnetic resonance, achieving an energy resolution of $\sim {10}^{- 23}\text{ }\text{ }\mathrm{eV}$. Using this magnetometer, we measure the energy shifts of nuclear spins induced by anomalous ${Z}^{‘ }$ boson-mediated spin-spin interactions. The null results set the most stringent constraints on anomalous neutron-neutron and neutron-proton spin couplings in the ${Z}^{‘ }$-boson mass ranges of 6.0–157.4 and $<129.6\text{ }\text{ }\mathrm{\mu }\mathrm{eV}$, respectively. Notably, our constraints surpass previous ones by up to 17 orders of magnitude in aforementioned mass ranges. Our experiments further set the most stringent constraints on neutron-proton spin couplings mediated by massless ${\gamma }^{‘ }$ paraphotons, surpassing previous constraints by at least 25 orders of magnitude. Our technique paves the way for intriguing future directions in the search for various anomalous spin-spin interactions, including those mediated by axions with projected sensitivity surpassing astrophysical limits.
Phys. Rev. Lett. 134, 223201 (2025)
Atomic & molecular processes in external fields, Hypothetical particle physics models, Magnetometry, Quantum sensing, Atomic ensemble, Atoms, Nuclear magnetic resonance, Nuclear spin resonance
Non-Markovian Effects in Quantum Rate Calculations of Hydrogen Diffusion with Electronic Friction
Research article | Dissipative dynamics | 2025-06-02 06:00 EDT
George Trenins and Mariana Rossi
Including non-Markovian electronic frictional memory effects in simulations of molecular diffusion on surfaces alters rate constants and tunneling crossover temperatures and explains the convergence between the Markovian simulations and experimental observations.
Phys. Rev. Lett. 134, 226201 (2025)
Dissipative dynamics, Friction, Quantum statistical mechanics, Surface diffusion, Interfaces, Density functional theory, Molecular dynamics, Path-integral methods
Physical Review X
Quartic Quantum Speedups for Planted Inference
| Quantum algorithms | 2025-06-02 06:00 EDT
Alexander Schmidhuber, Ryan O’Donnell, Robin Kothari, and Ryan Babbush
A new quantum algorithm solves planted inference problems with a quartic speedup and exponentially less memory than classical methods, offering practical gains even when considering quantum error correction.
Phys. Rev. X 15, 021077 (2025)
Quantum algorithms, Quantum algorithms & computation
arXiv
Revisiting the First, Second and Combined Laws of Thermodynamics
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-03 20:00 EDT
First, Second and Combined Laws of Thermodynamics are revised in terms of entropy change, partial entropy, partial volume, and chemical potential.
Statistical Mechanics (cond-mat.stat-mech), Materials Science (cond-mat.mtrl-sci)
Quantum theory of fractional topological pumping of lattice solitons
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-03 20:00 EDT
Julius Bohm, Hugo Gerlitz, Christina Jörg, Michael Fleischhauer
One of the hallmarks of topological quantum systems is the robust quantization of particle transport, which is the origin of the integer-valued Quantum Hall conductivity. In the presence of interactions the topological transport can also become fractional. Recent experiments on topological pumps constructed by arrays of photonic waveguides have demonstrated both integer and fractional transport of lattice solitons. Here a background medium mediates interactions between photons via a Kerr nonlinearity and leads to the formation of self-bound composites, called lattice solitons. Upon increasing the interaction strength of these solitons a sequence of transitions was observed from a phase with integer transport in a pump cycle through different phases of fractional transport to a phase with no transport. We here present a full quantum description of topological pumps of solitons. This approach allows us to identify a topological invariant, a many-body Chern number, determined by the band structure of the center-of-mass (COM) momentum of the solitons, which fully governs their transport. Increasing the interaction leads to a successive merging of COM bands which explains the observed sequence of topological phase transitions and also the potential for a breakdown of topological quantization for intermediate interaction strength
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Other Condensed Matter (cond-mat.other), Quantum Physics (quant-ph)
Holon metal, charge-density-wave and chiral superconductor from doping fractional Chern insulator and SU(3)$_1$ chiral spin liquid
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-03 20:00 EDT
Recent experiment observed a superconductor proximate to the $ \nu_h=-\frac{2}{3}=-1+\frac{1}{3}$ fractional quantum anomalous Hall (FQAH) insulator in twisted MoTe$ _2$ . One critical question is whether the normal state is a Fermi liquid with large Fermi surface, or a strongly correlated metallic state with small carrier density. In this work we develop a theory of possible phases from doping the $ \nu=-\frac{2}{3}$ fractional Chern insulator (FCI). We also point out that the problem is dual to doping a SU(3)$ _1$ chiral spin liquid(CSL) if we assume that the spin gap is finite. For both problems, a natural phase upon doping is a holon metal with three small Fermi pockets. The pocket is formed by a spinless charge $ -e$ holon in the doped CSL case and a charge $ -e/3$ fractionalized hole in the doped FCI case. The holon metal is likely unstable to pairing due to gauge field fluctuations, leading to a charge density wave (CDW) metal, but may be stabilized by magnetic field and shows an unusual quantum oscillation period. Two different chiral superconductors are possible, emerging from the CDW metal phase or directly from the holon metal. We note that a superconductor directly from anyon gas seems unlikely if the cheapest anyon is the elementary one with $ e/3$ charge.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
9+5 pages; 1 figure
Symmetry-deformed toric codes and the quantum dimer model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-03 20:00 EDT
Jiaxin Qiao, Yoshito Watanabe, Simon Trebst
Motivated by the recent introduction of a $ U(1)$ -symmetric toric code model, we investigate symmetry-based deformations of topological order by systematically deconstructing the Gauss-law-enforcing star terms of the toric code (TC) Hamiltonian. This “term-dropping” protocol introduces global symmetries that go beyond the alternative framework of “ungauging” topological order in symmetry-deformed models and gives rise to models such as the $ U(1)$ TC or $ XY$ TC. These models inherit (emergent) subsystem symmetries (from the original 1-form symmetry of the TC) that can give rise to (subextensive) ground-state degeneracies, which can still be organized by the eigenvalues of Wilson loop operators. However, we demonstrate that these models do not support topological or fracton order (as has been conjectured in the literature) due to the loss of (emergent) gauge symmetry. An extreme deformation of the TC is the quantum dimer model (QDM), which we discuss along the family of symmetry-deformed models from the perspective of subsystem symmetries, sublattice modulation, and quantum order-by-disorder mechanisms resulting in rich phase diagrams. For the QDM, this allows us to identify an emergent SO(2) symmetry for what appears to be a gapless ground state (by numerical standards) that is unstable to the formation of a plaquette valence bond solid upon sublattice modulation.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
12 pages, 7 figures and 1 table
Absence of topological order in the $U(1)$ checkerboard toric code
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-03 20:00 EDT
M. Vieweg, V. Kott, L. Lenke, A. Schellenberger, K.P. Schmidt
We investigate the $ U(1)$ checkerboard toric code which corresponds to the $ U(1)$ -symmetry enriched toric code with two distinct star sublattices. One can therefore tune from the limit of isolated stars to the uniform system. The uniform system has been conjectured to possess non-Abelian topological order based on quantum Monte Carlo simulations suggesting a non-trivial ground-state degeneracy depending on the compactification of the finite clusters. Here we show that these non-trivial properties can be naturally explained in the perturbative limit of isolated stars. Indeed, the compactification dependence of the ground-state degeneracy can be traced back to geometric constraints stemming from the plaquette operators. Further, the ground-state degeneracy is fully lifted in fourth-order degenerate perturbation theory giving rise to a non-topological phase with confined fracton excitations. These fractons are confined for small perturbations so that they cannot exist as single low-energy excitation in the thermodynamic limit but only as topologically trivially composite particles. However, the confinement scale is shown to be surprisingly large so that finite-size gaps are extremely small on finite clusters up to the uniform limit which is calculated explicitly by high-order series expansions. Our findings suggest that these gaps were not distinguished from finite-size effects by the recent quantum Monte Carlo simulation in the uniform limit. All our results therefore point towards the absence of topological order in the $ U(1)$ checkerboard toric code along the whole parameter axis.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
14 pages, 7 figures
Measuring the ferromagnetic resonance cone angle via static dipolar fields using diamond spins
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
B. A. McCullian, M. Chilcote, H. Yusuf, E. Johnston-Halperin, G. D. Fuchs
We demonstrate quantitative measurement of the ferromagnetic resonance (FMR) precession cone angle of a micro-scale sample of vanadium tetracyanoethylene (V[TCNE]$ _{x\sim 2}$ ) using diamond spins. V[TCNE]$ _{x\sim 2}$ is a low-damping, low-magnetization ferrimagnet with potential for scalable spintronics applications. Our study is motivated by the persistent need for quantitative metrology to accurately characterize magnetic dynamics and relaxation. Recently, diamond spins have emerged as sensitive probes of static and dynamic magnetic signals. Unlike analog sensors that require additional calibration, diamond spins respond to magnetic fields via a frequency shift that can be compared with frequency standards. We use a spin echo-based approach to measure the precession-induced change to the static stray dipolar field of a pair of V[TCNE]$ _{x\sim 2}$ discs under FMR excitation. Using these stray dipolar field measurements and micromagnetic simulations, we extract the precession cone angle. Additionally, we quantitatively measure the microwave field amplitude using the same diamond spins, thus forming a quantitative link between drive and response. We find that our V[TCNE]$ _{x\sim 2}$ sample can be driven to a cone angle of at least 6$ ^{\circ}$ with a microwave field amplitude of only 0.53 G. This work highlights the power of diamond spins for local, quantitative magnetic characterization.
Materials Science (cond-mat.mtrl-sci)
25 pages in manuscript format
How important is the dielectric constant in water modeling? Evaluation of the performance of the TIP4P/$\varepsilon$ force field and its compatibility with the Joung-Cheetham NaCl model
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-03 20:00 EDT
Łukasz Baran, Cosmin A. Dicu-Gohoreanu, Luis G. MacDowell
Efficient large scale computer simulations of complex aqueous solutions require the use of accurate but simple empirical force fields for water. However, the growing complexity of these systems is evidencing the difficulties to describe solution properties without due account of polarization. Conflicting strategies to remedy this problem are parametrizing water force fields to the dielectric constant or charge scaling of the solvated ions.
In this work we compare results from TIP4P/$ \varepsilon$ and OPC models, which are parametrized with an emphasis in the prediction of the dielectric constant, with results from TIP4P/2005, which is closer in spirit to the charge scaling strategy. The overall performance of the models is rated according to the Vega-Abascal benchmark. Our results show that TIP4P$ /\varepsilon$ and TIP4P/2005 perform equally good, with the OPC model lying significantly behind. TIP4P/$ \varepsilon$ can predict bulk phase properties (transport properties, thermal expansion coefficients, densities) of both liquid water and ice polymorphs, as well as surface tensions, with an accuracy very similar to TIP4P/2005, while performing very well for dielectric constants over a wide range of pressures and temperatures. On the other hand, TIP4P/2005 provides a better description of phase boundaries, including liquid-vapor and freezing transitions. However, the accurate prediction of dielectric constants allows TIP4P/$ \varepsilon$ to describe solution densities for model ions targeted to their crystal and melt properties. This is achieved without the need to rescale charges, modify the Lorentz-Berthelot rule or tune the ion’s Lennard-Jones parameters. Our findings hinge on the significance of dielectric constants as a target property and cast some doubt on the need for the appealing concept of charge scaling.
Soft Condensed Matter (cond-mat.soft), Applied Physics (physics.app-ph), Chemical Physics (physics.chem-ph)
43 pages, 9 figures, 6 tables
Expressivity of determinantal anzatzes for neural network wave functions
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-03 20:00 EDT
Ni Zhan, William A. Wheeler, Elif Ertekin, Ryan P. Adams, Lucas K. Wagner
Neural network wave functions have shown promise as a way to achieve high accuracy on the many-body quantum problem. These wave functions most commonly use a determinant or sum of determinants to antisymmetrize many-body orbitals which are described by a neural network. In previous literature, the spin has been treated as a non-dynamical variable, with each electron assigned a fixed spin label of up or down. Such a treatment is allowed for spin-independent operators; however, it cannot be applied to spin-dependent problems, such as Hamiltonians containing spin-orbit interactions. We provide an extension of neural networks to fully spinor wave functions, which can be applied to spin-dependent problems. We also show that for spin-independent Hamiltonians, a strict upper bound property is obeyed between a traditional Hartree-Fock like determinant, full spinor wave function, and the so-called full determinant wave function of Pfau et al. The relationship between a spinor wave function and the full determinant arises because the full determinant wave function is the spinor wave function projected onto a fixed spin, after which antisymmetry is implicitly restored in the spin-independent case. For spin-dependent Hamiltonians, the full determinant wave function is not applicable, because it is not antisymmetric. Numerical experiments on the H$ _3$ molecule and two-dimensional homogeneous electron gas confirm the bounds.
Strongly Correlated Electrons (cond-mat.str-el)
Transition from Optically Excited to Intrinsic Spin Polarization in WSe$_2$
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-03 20:00 EDT
Sebastian Hedwig, Gregor Zinke, Jürgen Braun, Benito Arnoldi, Aki Pulkkinen, Ján Minár, Hubert Ebert, Martin Aeschlimann, Benjamin Stadtmüller
Layered 2D van der Waals materials, such as transition metal dichalcogenides, are promising for nanoscale spintronic and optoelectronic applications. Harnessing their full potential requires understanding both intrinsic transport and the dynamics of optically excited spin and charge carriers – particularly the transition between excited spin polarization and the conduction band’s intrinsic spin texture. Here, we investigate the spin polarization of the conduction bands of bulk WSe$ _2$ using static and time-resolved spin-resolved photoemission spectroscopy, complemented by photocurrent calculations. Electron doping reveals the intrinsic spin polarization, while time-resolved measurements trace the evolution of excited spin carriers. We find that intervalley scattering is spin-conserving, with spin transport initially governed by photoexcited carriers and aligning with the intrinsic conduction band polarization after $ \sim$ 150 fs.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Self-ion implantation and structural relaxation in amorphous silicon
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
J.M. Gibson, Robe Elliman, T. Susi, C. Mangler
Self-ion implantation amorphization is an established approach to study the structure and properties of amorphous silicon (a-Si). Fluctuation Electron Microscopy (FEM) has consistently observed Medium-Range Order (MRO) in this system that is not consistent with the Continuous Random Network (CRN) model. Using this technique we find that the degree of MRO first increases on thermal annealing and then decreases before finally recrystallizing. We discuss this new result in the light of previous experimental studies and recent theoretical observations on the favorability of the paracrystalline (PC) model over the CRN in a-Si. At ion doses far above the minimum required to amorphize, a high defect density is found in the PC phase, which anneals out at 500oC. The PC structure after 500oC annealing is independent of the initial implantation conditions and appears to represent a metastable and highly-ordered structure. Higher-temperature annealing causes a reduction in the degree of MRO and the structure approaches but does not reach a fully continuous random network before eventually crystallizing above 600oC. The effect of high dose implantation is to increase the defect density in the as-implanted state and the annealing of these defects is likely responsible for the large characteristic heat evolution at low temperature.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Creation of a degenerate Bose-Bose mixture of erbium and lithium atoms
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-06-03 20:00 EDT
Jasmine Kalia, Jared Rivera, Rubaiya R Emran, William J Solorio Hernandez, Kiryang Kwon, Richard J Fletcher
We report the realization of a degenerate mixture of $ ^{166}$ Er and $ ^{7}$ Li atoms in their lowest spin state. The two species are sequentially laser-cooled and loaded into an optical dipole trap, then transported to a glass cell in which further cooling to degeneracy occurs. Since Er is more weakly trapped, it serves as a coolant for Li, and we observe efficient sympathetic cooling facilitated by a large interspecies elastic scattering cross section. Three-body losses are found to be small at the magnetic fields explored, making this platform promising for the study of interacting mixtures with large mass imbalance.
Quantum Gases (cond-mat.quant-gas), Atomic Physics (physics.atom-ph)
8 pages, 3 figures, 3 appendices
1D Transition Metal Oxide Chains as a Challenging Model for Ab Initio Calculations
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-03 20:00 EDT
Jila Amini, Mojtaba Alaei, Stefano de Gironcoli
Providing highly simplified models of strongly correlated electronic systems that challenge {\it ab initio} calculations can serve as a valuable testing ground to improve these methods. In this study, we present a comprehensive study of the structural, magnetic, and electronic properties of one-dimensional transition metal mono-oxide chains (VO, CrO, MnO, FeO, CoO, and NiO) using density functional theory (DFT), DFT+$ U$ , and coupled-cluster singles and doubles (CCSD) calculations. The Hubbard $ U$ parameter for DFT+$ U$ is determined using the linear response theory. In all systems studied except MnO, the presence of multiple local minima – primarily due to the electronic degrees of freedom associated with the d-orbitals – leads to significant challenges for DFT, DFT+U, and Hartree-Fock methods in finding the global minimum in ab initio calculations. Our results indicate that the antiferromagnetic (AFM) state is energetically favored for all chains, except CrO, when using DFT+$ U$ and PBE. We analyze the electronic band structures and find that while the PBE approximation often predicts metallic or half-metallic ground states for the ferromagnetic (FM) state, DFT+$ U$ approach successfully opens band gaps, correctly predicting insulating behavior in all cases. Furthermore, we compared the energy differences between the AFM and FM states using DFT+$ U$ and CCSD for CrO, MnO, FeO, CoO and NiO. Our findings indicate that CCSD predicts larger energy differences in some cases compared to DFT+$ U$ , suggesting that the Hubbard $ U$ parameter obtained through linear response theory may be overestimated when used to calculate energy differences between different magnetic states. For CrO, CCSD predicts an AFM ground state, in contrast to the predictions from DFT+$ U$ and PBE methods.
Strongly Correlated Electrons (cond-mat.str-el)
A higher dimensional generalization of the Kitaev spin liquid
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-03 20:00 EDT
We construct an exactly solvable model of a four-dimensional Kitaev spin liquid. The lattice structure is orthorhombic and each unit-cell contains six sublattice degrees of freedom. We demonstrate that the Fermi surface of the model is made up of two-dimensional surfaces. Additionally, we evaluate the energy cost of creating visons using scattering theory. The positive bond-flip energy suggests that the system’s ground state is flux-free, similar to the two-dimensional Kitaev honeycomb model. Our model sheds light on the realization of high-dimensional fractionalization. high-dimensional fractionalization.
Strongly Correlated Electrons (cond-mat.str-el)
12 pages, 8 figures
Low Spontaneous Brillouin Scattering in Anti-Resonant Hollow-Core Fibers in GHz Frequency Range
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Ryan E. Dunagin, Robbie Mears, Dario Bueno-Baques, Vasyl S. Tyberkevych, Yi Li, William J. Wadsworth, Zbigniew Celinski, Valentine Novosad, Dmytro A. Bozhko
Brillouin light scattering (BLS) is a powerful experimental tool that can be used to get insights into the fundamental and applied properties of matter, like dispersions of quasiparticles in a solid, as well as their spatio-temporal dynamics. Many applications of light scattering favor the use of optical fibers in place of free-space optics. In this work, we compare the performance of anti-resonant hollow core fibers to that of conventional solid core fused silica fibers for BLS experiments in the GHz frequency range. Conventional fibers are barely suitable for low-noise measurements because of the spontaneous scattering of the photons on various phononic modes present in the core and cladding. In the case of the hollow-core fiber, we identify a range of discrete phononic modes and associate them with the various acoustic modes of the structure surrounding the hollow core using finite-element numerical simulations. The measured relative intensity of the spontaneous BLS signal from these modes is orders of magnitude smaller than that of a solid-core fiber, making anti-resonant hollow-core fibers one of the best solutions for the single-mode light guidance for BLS and potentially other low-noise photonic experiments.
Materials Science (cond-mat.mtrl-sci), Optics (physics.optics)
Influence of X-ray Irradiation on the Magnetic and Structural Properties of Gadolinium Silicide Nanoparticles for Self-Regulating Hyperthermia
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Samantha E. Smith, Santiago Bermudez, Pavan Chaitanya, Zoe Boekelheide, Jessika Rojas Marin, Ravi L. Hadimani
Magnetic hyperthermia treatment (MHT) utilizes heat generated from magnetic nanoparticles (MNPs) under an alternating magnetic field (AMF) for therapeutic applications. Gadolinium silicide (Gd5Si4) has emerged as a promising MHT candidate due to its self-regulating heating properties and potential biocompatibility. However, the impact of high-dose X-ray irradiation on its magnetic behavior remains uncertain. This study examines Gd5Si4 nanoparticles exposed to 36 and 72 kGy X-ray irradiation at a high-dose rate (120 Gy/min). While X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy confirm no structural or compositional changes, transmission electron microscopy reveals localized lattice distortions, along with observable changes in magnetic properties, as evidenced in magnetization vs. temperature and hysteresis measurements. Despite this, magnetocaloric properties and specific loss power (SLP) remain unaffected. Our findings confirm the stability of Gd5Si4 under high-dose X-ray irradiation, supporting its potential for radiotherapy (RT) and magnetocaloric cooling in deep-space applications.
Materials Science (cond-mat.mtrl-sci), Medical Physics (physics.med-ph)
Theory of terahertz pulse transmission through ferroelectric nanomembranes
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Yujie Zhu, Aiden Ross, Xiangwei Guo, Venkatraman Gopalan, Long-Qing Chen, Jia-Mian Hu
An analytical model is developed to predict the temporal evolution of the lattice polarization in ferroelectric nanomembranes upon the excitation by a terahertz (THz) electromagnetic pulse of an arbitrary waveform, and the concurrent transmission of the THz pulse in both the linear and the nonlinear regimes. It involves the use of the perturbation method to solve the equation of motion for the lattice polarization in both unclamped and strained ferroelectric nanomembranes within the framework of Landau-Ginzburg-Devonshire theory. The model is applicable to perovskite oxides such as BaTiO3 and SrTiO3, wurtzite Al1-xScxN, and trigonal LiNbO3. Our analytical model provides a theoretical basis for determining the thermodynamic and kinetic parameters of ferroelectric materials through THz transmission experiment. The calculation results also suggest an approach to reversing the chirality of a circularly polarized THz pulse by harnessing the resonant polarization-photon coupling in ferroelectrics. This capability of chirality reversal, along with the high tunability from a strain applied along any arbitrarily oriented in-plane axis, provides new opportunities for THz wave modulation without relying on complex metasurface designs.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Huge anisotropic magneto-thermal switching in high-purity polycrystalline compensated metals
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Poonam Rani, Yuto Watanabe, Takuma Shiga, Yuya Sakuraba, Hikaru Takeda, Minoru Yamashita, Ken-ichi Uchida, Aichi Yamashita, Yoshikazu Mizuguchi
Magneto-thermal transport is a promising physical property for thermal management applications. Magneto-thermal switching enables active control of heat flows, and a high switching ratio is desirable for improving performance. Here, we report on the observation of a huge magneto-thermal switching (MTS) effect in high-purity (5N) Pb polycrystalline wires, where magnetic fields perpendicular to the heat current direction are applied at low temperatures. At T = 3 K and B = 0.1 T, the measured thermal conductivity (\k{appa}) of the Pb wire is about 2500 W m-1 K-1 but is reduced to ~150 and ~5 W m-1 K-1 at B = 1 and 9 T, respectively. This strong suppression is attributed to magnetoresistance in compensated metals. Although the huge magnetoresistance has been studied in single crystals with field along the selected orbitals, our results demonstrate that a huge MTS can similarly be realized even in flexible polycrystalline wires. This finding highlights the practical potential of magneto-thermal control in low-temperature thermal management, including applications in space environments where temperatures are around 3 K.
Materials Science (cond-mat.mtrl-sci)
20 pages, 4 figures. SI
Resonant interlayer coupling in NbSe$_2$-graphite epitaxial moir{é} superlattices
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
S. Mo, K. Kovalenka, S. Buchberger, B.K. Saika, A. Azhar, A. Rajan, A. Zivanovic, Y.-C. Yao, R.V. Belosludov, M.D. Watson, M.S. Bahramy, P.D.C. King
Moir{é} heterostructures, created by stacking two-dimensional (2D) materials together with a finite lattice mismatch or rotational twist, represent a new frontier of designer quantum materials. Typically, however, this requires the painstaking manual assembly of heterostructures formed from exfoliated materials. Here, we observe clear spectroscopic signatures of moir{é} lattice formation in epitaxial heterostructures of monolayer (ML) NbSe$ _2$ grown on graphite substrates. Our angle-resolved photoemission measurements and theoretical calculations of the resulting electronic structure reveal moir{é} replicas of the graphite $ \pi$ states forming pairs of interlocking Dirac cones. Interestingly, these intersect the NbSe$ _2$ Fermi surface at the $ \mathbf{k}$ -space locations where NbSe$ _2$ ‘s charge-density wave (CDW) gap is maximal in the bulk. This provides a natural route to understand the lack of CDW enhancement for ML-NbSe$ _2$ /graphene as compared to a more than four-fold enhancement for NbSe$ _2$ on insulating support substrates, and opens new prospects for using moir{é} engineering for controlling the collective states of 2D materials.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
11 pages including supplementary information, 4+5 figures
Topological phase control in Mn1-xGexBi2Te4 via spin-orbit coupling and magnetic configuration engineering
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
A.M. Shikin, N.L. Zaitsev, A.V. Eryzhenkov, R.V. Makeev, T.P. Estyunina, D.A. Estyunin, A.V. Tarasov
Magnetic topological systems based on MnBi2Te4 have recently attracted significant attention due to their rich interplay between magnetism and topological electronic states. In this work, using density functional theory (DFT), we investigate topological phase transitions (TPTs) in Mn1-xGexBi2Te4 compounds with both ferromagnetic (FM) and antiferromagnetic (AFM) ordering under variations of spin-orbit coupling (SOC) strength and uniaxial strain along the c axis. We show that the emergence of a Weyl semimetal (WSM) phase requires the crossing of bands with opposite sz spin projections along the {\Gamma}Z direction. Modulation of SOC and strain can annihilate Weyl points via spin-selective hybridization, driving transitions into trivial or topological insulating phases. Furthermore, we demonstrate that local asymmetry in Mn/Ge substitution, particularly at 37.5% Ge concentration (Mn0.625Ge0.375Bi2Te4) can locally disrupt AFM interlayer coupling and induce a WSM state even in globally AFM systems, without external remagnetization. To optimize Weyl point separation and enhance the anomalous Hall effect (AHE), we propose partial substitution of Mn by Fe and Te by Se.
Materials Science (cond-mat.mtrl-sci)
Complete universal scaling of first-order phase transitions in the two-dimensional Ising model
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-03 20:00 EDT
Phase transitions, as one of the most intriguing phenomena in nature, are divided into first-order phase transitions (FOPTs) and continuous ones in current classification. While the latter shows striking phenomena of scaling and universality, the former has recently also been demonstrated to exhibit scaling and universal behavior within a mesoscopic, coarse-grained Landau-Ginzburg theory. Here we apply this theory to a microscopic model – the paradigmatic Ising model, which undergoes FOPTs between two ordered phases below its critical temperature – and unambiguously demonstrate universal scaling behavior in such FOPTs. These results open the door for extending the theory to other microscopic FOPT systems and experimentally testing them to systematically uncover their scaling and universal behavior.
Statistical Mechanics (cond-mat.stat-mech)
5 pages, 1 figure
Magnetic interactions as a pivotal determinant in stabilizing a novel AgIIAgIIIF5 polymorph with high spin AgIII
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Daniel Jezierski, Wojciech Grochala
Based on theoretical calculations, we introduce a new AgIIAgIIIF5 monoclinic polymorph with a rare high spin AgIII. Our analysis of the experimental xray diffraction data available in the literature reveals that this polymorph was likely prepared in the past in a mixture with the triclinic form of the same compound. Theoretical calculations reproduce very well the lattice parameters of both forms. Calculations suggest that under ambient conditions, the monoclinic form is the more energetically stable phase of Ag2F5. We predict a strong one-dimensional antiferromagnetic superexchange between silver cations of different valences with superexchange constant of minus 207 meV (hybrid functional result). The polymorph with high spin AgIII owes its stability over the one with low spin AgIII, to these magnetic interactions.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
17 pages, 6 figures, 8 tables, and supplementary material of 4 pages
Ab-initio Study of Structural, Magnetic, Optoelectronic and Thermo-Physical Properties of HoPdBi Half-Heusler Semimetal
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Tanvir Khan, F. Parvin, S. H. Naqib
In this investigation, we have used the density functional theory (DFT) to investigate several aspects of the half-Heusler compound HoPdBi. The following properties have been studied: spin polarized electronic properties, magnetic moment, phonon dispersion with phonon density of states, structural, elastic properties, optical characteristics, and thermo-physical features. The calculated unit cell volume and ground-state lattice characteristics closely match the experimental results. This study is the first to examine the optoelectronic, thermo-physical, and elastic characteristics of HoPdBi. The mechanical stability requirements were met by the calculated elastic constants. The compound’s ductility is shown by the estimated Pugh’s ratio, Poisson’s ratio, and Cauchy pressure. Band structures and electronic energy density of states have been evaluated in order to better understand the magnetic features with spin polarization. Band structure simulations were conducted with and without the spin-orbit coupling (SOC) effect in order to look into any topological signature. The electrical band structure of the compound shows semi-metallic properties. The reflectivity, absorption coefficient, refractive index, dielectric function, optical conductivity, and loss function of this semi-metal have all been thoroughly examined. The compound is a good reflector in infrared region and a good absorber of ultraviolet (UV) light. This compound is a suitable candidate for high temperature applications and possesses potential as heat sink because of its high melting point and thermal conductivity. It is also suitable for spintronics applications. The majority of this study’s findings are completely novel.
Materials Science (cond-mat.mtrl-sci)
Potassium Decoration on Graphenyldiene Monolayer for Advanced Reversible Hydrogen Storage
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Jose A. S. Laranjeira, Nicolas F. Martins, Kleuton A. L. Lima, Bill. D. Aparicio-Huacarpuma, Luiz A. Ribeiro Junior, Xihao Chen, Douglas S. Galvao, Julio R. Sambrano
Potassium-decorated graphenyldiene (K@GPD) is investigated as a promising two-dimensional material for reversible hydrogen storage using first-principles density functional theory calculations. Potassium atoms bind strongly to the GPD monolayer, and ab initio molecular dynamics (AIMD) simulations confirm the thermal stability of the functionalized system at 300 K. Hydrogen adsorption energies range from -0.11 to -0.14 eV per H$ _2$ , denoting reversible storage. At full coverage (18 H$ _2$ molecules), the system reaches a storage capacity of 8.82 wt%, exceeding the U.S. DOE target. AIMD simulations reveal spontaneous H$ _2$ desorption at ambient temperature, demonstrating excellent reversibility.
Materials Science (cond-mat.mtrl-sci)
TPHE-Graphene: A First-Principles Study of a New 2D Carbon Allotrope for Hydrogen Storage
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
José A. S. Laranjeira, Nicolas F. Martins, Kleuton A. L. Lima, Luis A. Cabral, Luiz A. Ribeiro, Douglas S. Galvão, Julio R. Sambrano
The shift from fossil fuels to renewable energy sources is essential for reducing global carbon emissions and addressing climate change. Developing advanced materials for efficient hydrogen storage enables sustainable energy solutions in this context. Herein, we propose sodium-decorated TPHE-graphene as a high-performance two-dimensional material for hydrogen storage. Density functional theory (DFT) calculations demonstrate that TPHE-graphene exhibits dynamical, thermal, energetic, and mechanical stability, as confirmed by cohesive energy, phonon dispersion, and molecular dynamics simulations. The monolayer displays metallic behavior and a high Young’s modulus of 250.46 N/m. Upon sodium decoration, strong chemisorption occurs with a binding energy of -2.08 eV and minimal tendency for Na atom clustering. Hydrogen adsorption analysis reveals that each Na atom can bind up to five H$ _2$ molecules, resulting in a gravimetric storage capacity of 9.52 wt%. The calculated H$ _2$ adsorption energies range from -0.22 eV to -0.18 eV, falling within the ideal range for reversible adsorption under ambient conditions. These findings highlight Na-decorated TPHE-graphene as a structurally robust and efficient hydrogen storage material well-suited for future green energy applications.
Materials Science (cond-mat.mtrl-sci)
Robust Charge-Density Wave Correlations in Optimally-Doped YBa2Cu3Oy
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-03 20:00 EDT
Rui Zhou, Igor Vinograd, Hadrien Mayffre, Juan Porras, Hun-Ho Kim, Toshinao Loew, Yiran Liu, Matthieu Le Tacon, Bernhard Keimer, Marc-Henri Julien
Charge-density wave (CDW) order is a key property of high-Tc cuprates, but its boundaries in the phase diagram and potential connections to other phases remain controversial. We report nuclear magnetic resonance (NMR) measurements in the prototypical cuprate YBa2Cu3Oy demonstrating that short-range static CDW order remains robust at optimal doping (p=0.165), exhibiting a strength and temperature dependence in the normal state similar to those observed at p=0.11 in the underdoped regime. For an overdoped sample with p=0.184, we detect no static CDW down to T=Tc, though weak CDW order plausibly emerges below Tc. More broadly, we argue that both quenched disorder and competition with superconductivity influence the apparent boundary of the CDW phase, likely causing an underestimation of its intrinsic extent in doping. These findings challenge the view that the CDW phase boundary lies below p\ast=0.19, widely regarded as the critical doping where the pseudogap phase ends in YBa2Cu3Oy.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
SI included
Molecular dynamics simulation of the effects of neutron irradiation on Caesium Lead Bromide
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Zhongming Zhang, Samuel Murphy, Michael Aspinall
With the development of fast neutron reactors and nuclear fusion reactors, it is necessary to find new radiation-hardened high-flux core neutron detectors. The use of perovskite Caesium Lead Bromide (CsPbBr$ _3$ ) for neutron radiation detection is a new research direction. However, at high temperatures, the effects of neutron radiation, especially the Primary Knock-out Atom (PKA) and Displacement Per Atom (DPA), and the defect distribution at the molecular level have not been reported. This study investigated the effect on CsPbBr$ _3$ produced by 14 MeV neutron irradiation under 100 K to 400 K. Molecular dynamics methods are used to model the distribution of vacancies and interstitial atoms at the molecular level of materials. This study obtained the displacement threshold energies of three atoms in CsPbBr$ _3$ and obtained the distribution of vacancies and interstitial atoms within the material over time. Monte Carlo simulations were used to obtain PKA and DPA information in CsPbBr$ _3$ under neutron irradiation. This research will help to further study the performance changes of halide perovskites under neutron irradiation to verify the possibility of using them as radiation-hardened neutron detectors.
Materials Science (cond-mat.mtrl-sci)
Ballistic particle transport and Drude weight in mono-atomic gases
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-06-03 20:00 EDT
Frank Göhmann, Andreas Klümper, Karol K. Kozlowski
Owing to the fact that, in the particular case of non-relativistic mono-atomic gases, the particle current operator is proportional to the operator of the total momentum, the particle transport in such systems is always ballistic and fully characterized by a Drude weight $ \Delta$ . The Drude weight can be calculated as a generalized susceptibility from a generalized Gibbs ensemble. For the case of the integrable one dimensional Bose gas with contact interactions this susceptibility can be obtained exactly and explicitly from a generalized Yang-Yang thermodynamic formalism. The result is temperature independent and given by $ \Delta = 2 \pi D = 2 k_F$ , where $ D$ is the density of the gas and $ k_F$ its Fermi momentum. Our expression, derived by first principle calculations, confirms a more involved formula obtained heuristically by means of generalized hydrodynamics.
Quantum Gases (cond-mat.quant-gas), Mathematical Physics (math-ph)
12 pages
Observation of pseudogap in Cr_{1-x}Y_xN magnetic alloy and its impact on the Seebeck coefficient by ab-initio calculations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Luis Felipe Leon-Pinzon, Elisabeth Restrepo-Parra, Andres Manuel Garay-Tapia
Thermoelectric materials require high electronic conductivity and low thermal conductivity. CrN has been shown to have low phononic thermal conductivity, making it a potential candidate for thermoelectric applications. In addition, similarities have been observed between YN and ScN suggesting that the CrYN alloy may have interesting thermoelectric properties. As CrYN has not been studied in detail at the level of thermoelectric properties, the first study on CrYN alloy of Seebeck coefficient and zT figure of merit is proposed in this study. For this purpose, cubic special quasirandom structures were constructed at values of x = 0.25, 0.5 and 0.75 in the alloy Cr_{1-x}Y_xN starting from different magnetic structures. After analyzing lattice parameters, Cr magnetic moments, octahedron deformation, second neighbors distribution around metals, density of states and band structures, it was concluded that to obtain high values of Seebeck coefficient and zT, it is necessary the presence of a pseudo gap in both spin channels and it is also necessary that the Fermi level is on a steep decreasing slope of number of states, since due to Motts approximation, the value of this slope is proportional to the Seebeck coefficient. Density of states of all the structures shows a metallic behavior. In structures with x=0.5, the presence of small indirect energy gaps is observed. Although no structure retains the initial magnetic configuration, there is a possible influence of this on the electronic structure. Considerable deformations in octahedra can suppress thermoelectric properties.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el), Computational Physics (physics.comp-ph)
Effect of crystallinity on the frictional and wear performance of molybdenum disulfide: A molecular dynamics study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Abhiram B R, Ilia Ponomarev, Tomas Polcar
The frictional and wear performance of molybdenum disulfide (MoS2) is significantly influenced by its intrinsic arrangement of crystals or crystallinity. In this study, we investigate the effect of crystallinty on coefficient of friction (COF) and wear in MoS2 using a suite of reactive molecular dynamics (MD) simulations. A range of configurations, from amorphous to crystalline, is modeled to capture the effect of structural order on the tribological behavior. To study friction and wear, we simulate the sliding of a spherical rigid carbon body over the MoS2 surface under varying crystallinity conditions. Our results reveal a pronounced reduction in COF with decreasing crystallinity, with crystalline MoS2 exhibiting superlubricity. This behavior is attributed to the preservation of a flat sliding surface and frictional anisotropy, which enables lateral movement along low-resistance paths. In contrast, amorphous and polycrystalline MoS2 with lower degrees of crystallinity displays a substantially higher COF, driven by increased surface roughness and atomic-scale energy dissipation. Furthermore, we examine the wear mechanisms under high normal loads, demonstrating that crystallinity enhances wear resistance by mitigating material deformation. These findings provide atomic-scale insights into the tribological performance of MoS2, emphasizing the critical role of structural order in achieving ultralow friction. Our work corroborates with previous studies on superlubricity in MoS2 and extends this understanding to rigid-body sliding conditions, offering valuable implications for designing low-friction and wear resistant solid lubricants.
Materials Science (cond-mat.mtrl-sci)
High-Efficiency, High-Fidelity Charge Initialization of Shallow Nitrogen Vacancy Centers in Diamond
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Marjana Mahdia, Artur Lozovoi, Jared Rovny, Zhiyang Yuan, Carlos A. Meriles, Nathalie P. de Leon
Nitrogen vacancy (NV) centers in diamond exhibit long spin coherence times, optical initialization, and optical spin readout under ambient conditions, making them excellent quantum sensors. However, the conventional scheme for charge state initialization based on off-resonant green excitation results in significant state preparation errors, typically around 30%. One method for improving charge state initialization fidelity is to use multicolor excitation, which has been demonstrated to achieve a near-unity preparation fidelity for bulk NV centers by using a few milliseconds of near-infrared (5 mW) and green (10 {\mu}W) excitation. The translation of such schemes to NV centers near the diamond surface with higher efficiency optical pumping would enable myriad tasks in nanoscale sensing. Here, we demonstrate a protocol for efficient charge initialization of shallow NV centers between 5 nm and 15 nm from the diamond surface. By carefully studying the charge dynamics of shallow NV centers, we identify a region of parameter space that allows for near-unity (95%) charge initialization within 300 {\mu}s of near-infrared (1 mW) and green (10 {\mu}W) excitation. The time to 90% charge initialization can be as fast as 10 {\mu}s for 4 mW of near-infrared and 39 {\mu}W of green illumination. This fast, efficient charge initialization protocol will enable nanoscale sensing applications where state preparation errors currently prohibit scaling, such as measuring higher-order multi-point correlators.
Materials Science (cond-mat.mtrl-sci), Quantum Physics (quant-ph)
A Foundation Model for Non-Destructive Defect Identification from Vibrational Spectra
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Mouyang Cheng, Chu-Liang Fu, Bowen Yu, Eunbi Rha, Abhijatmedhi Chotrattanapituk, Douglas L Abernathy, Yongqiang Cheng, Mingda Li
Defects are ubiquitous in solids and strongly influence materials’ mechanical and functional properties. However, non-destructive characterization and quantification of defects, especially when multiple types coexist, remain a long-standing challenge. Here we introduce DefectNet, a foundation machine learning model that predicts the chemical identity and concentration of substitutional point defects with multiple coexisting elements directly from vibrational spectra, specifically phonon density-of-states (PDoS). Trained on over 16,000 simulated spectra from 2,000 semiconductors, DefectNet employs a tailored attention mechanism to identify up to six distinct defect elements at concentrations ranging from 0.2% to 25%. The model generalizes well to unseen crystals across 56 elements and can be fine-tuned on experimental data. Validation using inelastic scattering measurements of SiGe alloys and MgB$ _2$ superconductor demonstrates its accuracy and transferability. Our work establishes vibrational spectroscopy as a viable, non-destructive probe for point defect quantification in bulk materials, and highlights the promise of foundation models in data-driven defect engineering.
Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG)
14 pages, 5 figures
Cubic BeB$_2$: A metastable $p$-type conductive material from first principles
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Xiao Zhang, Shashi Mishra, Elena R. Margine, Emmanouil Kioupakis
Boron forms a wide variety of compounds with alkaline earth elements due to its unique bonding characteristics. Among these, binary compounds of Be and B display particularly rich structural diversity, attributed to the small atomic size of Be. Cubic BeB$ _2$ is a particularly interesting phase, where Be donates electrons to stabilize a diamond-like boron network under high pressure. In this work, we employ \textit{ab initio} methods to conduct a detailed investigation of cubic BeB$ _2$ and its functional properties. We show that this metastable phase is dynamically stable under ambient conditions, and its lattice match to existing substrate materials suggests possible epitaxial stabilization via thin-film growth routes. Through a comprehensive characterization of its electronic, transport, and superconductivity properties, we demonstrate that cubic BeB$ _2$ exhibits high hole concentrations and high hole mobility, making it a potential candidate for efficient $ p$ -type transport. In addition, cubic BeB$ _2$ is found to exhibit low-temperature superconductivity at degenerate doping levels, similar to several other doped covalent semiconductors such as diamond, Si, and SiC.
Materials Science (cond-mat.mtrl-sci)
9 pages, 7 figures
Anomalous magnetic response in the Au-Al-Gd 1/1 quasicrystal approximant
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Takafumi D. Yamamoto, Tasuku Watanae, Farid Labib, Asuka Ishikawa, Shintaro Suzuki, Ryuji Tamura
The magnetic response of the Tsai-type 1/1 Au-Al-Gd approximant crystals (ACs) was quantitatively investigated in terms of the magnetic entropy change ($ \Delta S_{M}$ ) for different magnetic ground states. A comprehensive $ \Delta S_{M}$ map over a wide electron concentration range has been established, demonstrating the detailed variation of $ \Delta S_{M}$ across the entire magnetic phase diagram in the Tsai-type 1/1 ACs. Near the boundaries of the ferromagnetic (FM) phase, a clear deviation from the mean-field theory (MFT) was observed in both the Curie temperature ($ T_{C}$ ) and magnetic field ($ H$ ) dependences of the maximum magnetic entropy change ($ \Delta S_{M}^{max}$ ). Contrary to general expectations, a high $ \Delta S_{M}^{max}$ (7.2 J/K mol-Gd under a 5 T field variation), even comparable to those of candidate materials for low-temperature magnetic refrigeration, was obtained within the antiferromagnetic (AFM) region near the FM / AFM phase boundary. The unexpected enhancement of $ \Delta S_{M}^{max}$ toward the AFM region under high magnetic fields indicates an anomalous magnetic response in the present Tsai-type 1/1 AC, which is presumably associated with the breakdown of the MFT. The present finding suggests that tuning the magnetic ground state across the phase boundary is an effective strategy to enhance $ \Delta S_{M}$ , even in general rare-earth intermetallic compounds.
Materials Science (cond-mat.mtrl-sci)
Physical Review B (accepted)
Hole clustering and mutual interplay in three-band Hubbard model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-03 20:00 EDT
Mi Jiang, Yi-feng Yang, Guang-Ming Zhang
Recent scanning tunnelling spectroscopy (STS) experiments revealed remarkable role of a supercell consisting $ 4\times4$ CuO$ _2$ unit cells in the emergence of local nematic state and preformed local Cooper pairs and phase coherent cuprate superconductivity. By employing the numerically exact determinant Quantum Monte Carlo simulations, we mimic the effects of experimental Ca vacancy by an external local potential to investigate the charge and spectral properties of the system hosting two doped holes. The model numerically support the role of the $ 4\times4$ supercell as the building block of hole doped cuprates via the hole density distribution and local spectra around the local potential. Our results might provide a theoretical support on the experimental observations and a platform for investigating local charge order and local Cooper pairs on the $ 4\times4$ supercell as the plausible route to understanding unconventional cuprate superconductivity.
Strongly Correlated Electrons (cond-mat.str-el)
5 pages, 5 figures
Fröhlich Condensation of Bosons: Graph texture of curl flux network for nonequilibrium properties
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-03 20:00 EDT
Feihong Liu, Chase Slowey, Xuanhua Wang, Dangyuan Lei, Zhiyue Lu, Zhedong Zhang
Nonequilibrium condensates of bosons subject to energy pump and dissipation are investigated, manifesting the Fröhlich coherence proposed in 1968. A quantum theory is developed to capture such a nonequilibrium nature, yielding a certain graphic structure arising from the detailed-balance breaking. The results show a network of probability curl fluxes that reveals a graph topology. The winding number associated with the flux network is thus identified as a new order parameter for the phase transition towards the Fröhlich condensation (FC), not attainable by the symmetry breaking. Our work demonstrates a global property of the FCs, in conjunction with the coherence of cavity polaritons that may exhibit robust cooperative phases driven far from equilibrium.
Statistical Mechanics (cond-mat.stat-mech)
7 pages, 3 figures
New universality classes and BKT transition in the vortex lattice phases of Kagome Ice
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-03 20:00 EDT
Wei Zhang, Wanzhou Zhang, Jie Zhang, Chengxiang Ding, Youjin Deng
Inspired by the experimental realization of direct Kagome spin ice [arXiv:2404.19377], the theoretical six-vertex model on the Kagome lattice is systematically simulated using the directed loop Monte Carlo method. Four distinct vortex lattice phases are identified: (i) Ferromagnetic leg states and vortex lattice order on both triangular and honeycomb faces, with a winding number $ k = 1 $ . (ii) Antiferromagnetic leg states and vortex lattice order on both types of faces, with $ k = -2 $ on the honeycomb faces and $ k = 1 $ on the triangular faces. (iii) Paramagnetic leg states and vortex lattice order on the triangular faces with $ k = 1 $ . (iv) Paramagnetic leg states and vortex lattice order on the honeycomb faces with $ k = 1 $ . As for ferromagnetic to different types of magnetic disorder phase, besides the Ising universality class with $ y_t = 1 $ , a new critical exponent $ y_t = 1.317(6) $ has also been found. The transition between the third and fourth types of vortex lattice phases occurs with the new exponent $ y_t=1.340(3)$ . The third and fourth types of the vortex lattice phase to the vortex disorder phase are found to be of the Berezinskii-Kosterlitz-Thouless type. These findings contribute to the search for and understanding of ice on complex lattices.
Statistical Mechanics (cond-mat.stat-mech)
14 pages, 15 figures
A network of parametrically driven silicon nitride mechanical membranes
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-03 20:00 EDT
Luis Mestre, Suyash Singh, Gabriel Margiani, Letizia Catalini, Alexander Eichler, Vincent Dumont
Networks of nonlinear resonators offer a promising platform for analog computing and the emulation of complex systems. However, realizing such networks remains challenging, as it requires resonators with high quality factors, individual frequency tunability, and strong inter-resonator coupling. In this work, we present a system that meets all these criteria. Our system is based on metallized silicon nitride membranes that are coupled via their common substrate and controlled capacitively via electrodes. We demonstrate individual frequency tuning and strong parametric driving of each membrane. Notably, we tune membrane frequencies through avoided crossings and demonstrate tunability of the coupled membrane’s parametric response. This platform provides a scalable and controllable setting for exploring collective phenomena, dynamical phase transitions, nonlinear topology, and analog computing.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph)
11 pages, 9 figures
Dynamical Properties of Dense Associative Memory
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-06-03 20:00 EDT
Kazushi Mimura, Jun’ichi Takeuchi, Yuto Sumikawa, Yoshiyuki Kabashima, Anthony C. C. Coolen
The dense associative memory is one of the basic modern Hopfield networks and can store large numbers of memory patterns. While the stationary state storage capacity has been investigated so far, its dynamical properties have not been discussed. In this paper, we analyze the dynamics by means of an exact approach based on generating functional analysis. It allows us to investigate convergence properties as well as the size of the attraction basins. We also analyze the stationary state of the updating rule.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
10 pages, 1 figure
Observation of universal topological magnetoelectric switching in multiferroic GdMn2O5
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Haowen Wang, Fan Wang, Ming Yang, Yuting Chang, Mengyi Shi, Liang Li, Jun-Ming Liu, Junfeng Wang, Shuai Dong, Chengliang Lu
Topological magnetoelectricity was recently revealed as an emergent topic, which opens a unique route to precisely control magnetoelectric functionality. Here we report the synchronous magnetic-electric-cycle operation of topological magnetoelectric switching in GdMn2O5. Compared with pure magnetic-cycle operation, this topological winding can be accessed in a much broader parameter space, i.e. orientation of magnetic field is not limited to the magic angle and the effect can persist up to the Curie temperature. The fine tuning of free energy landscape is responsible to this topological behavior.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Phys. Rev. Lett. 134, 016708 (2025)
Hybrid scaling mechanism of critical behavior in the overlapping critical regions of classical and quantum Yang-Lee edge singularities
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-03 20:00 EDT
Yue-Mei Sun, Wen-Jing Yu, Xin-Yu Wang, Liang-Jun Zhai
Recently, the study of scaling behavior in Yang-Lee edge singularities (YLES) has attracted sustained attention. However, the scaling mechanism for the overlapping critical region between classical and quantum YLES remains unclear. In this work, we investigate this question, and a hybrid scaling mechanism is introduced to characterize the scaling behavior in the overlapping regions. The hybrid scaling mechanism asserts that in the overlapping region the scaling behavior can be described by the scaling function for both critical regions simultaneously, and it results in a constraint on the scaling functions. The transverse Ising chain in an imaginary longitudinal field, which exhibits $ (0+1)$ dimensional (D) and $ (1+1)$ D quantum YLES phase transitions at zero temperature, and $ (0+0)$ D and $ (1+0)$ D classical YLES phase transitions at finite temperature, is employed as a model to test this hybrid scaling mechanism. The scaling functions in the critical regions of $ (0+1)$ D and $ (1+1)$ D quantum YLES as well as $ (0+0)$ D and $ (1+0)$ D classical YLES of such model are systematically investigated. Furthermore, the hybrid scaling mechanisms in overlapping critical regions, particularly between classical and quantum YLES, are thoroughly examined. Through this study, we have established a scaling mechanism capable of describing behaviors in the overlapping critical regions between classical and quantum phase transitions, which also facilitates the extraction of quantum phase transition information from classical phase transition systems.
Statistical Mechanics (cond-mat.stat-mech)
Anomalous current fluctuations and mobility-driven clustering
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-03 20:00 EDT
Tanmoy Chakraborty, Punyabrata Pradhan
We study steady-state current fluctuations in hardcore lattice gases on a ring of $ L$ sites, where $ N$ particles perform symmetric, {\it extended-ranged} hopping. The hop length is a random variable depending on a length scale $ l_0$ (hopping range) and the inter-particle gap. The systems have mass-conserving dynamics with global density $ \rho = N/L$ fixed, but violate detailed balance. We consider two analytically tractable cases: (i) $ l_0 = 2$ (finite-ranged) and (ii) $ l_0 \to \infty$ (infinite-ranged); in the latter, the system undergoes a clustering or condensation transition below a critical density $ \rho_c$ . In the steady state, we compute, exactly within a closure scheme, the variance $ \langle Q^2(T) \rangle_c = \langle Q^2(T) \rangle - \langle Q(T) \rangle^2$ of the cumulative (time-integrated) current $ Q(T)$ across a bond $ (i,i+1)$ over a time interval $ [0, T]$ . We show that for $ l_0 \to \infty$ , the scaled variance of the time-integrated bond current, or equivalently, the mobility diverges at $ \rho_c$ . That is, near criticality, the mobility $ \chi(\rho) = \lim_{L \to \infty} [\lim_{T \to \infty} L \langle Q^2(T, L) \rangle_c / 2T] \sim (\rho - \rho_c)^{-1}$ has a simple-pole singularity, thus providing a dynamical characterization of the condensation transition, previously observed in a related mass aggregation model by Majumdar et al.\ [{\it Phys.\ Rev.\ Lett.\ {\bf 81}, 3691 (1998)}]. At the critical point $ \rho = \rho_c$ , the variance has a scaling form $ \langle Q^2(T, L) \rangle_c = L^{\gamma} {\cal W}(T/L^{z})$ with $ \gamma = 4/3$ and the dynamical exponent $ z = 2$ . Thus, near criticality, the mobility {\it diverges} while the diffusion coefficient remains {\it finite}, {\it unlike} in equilibrium systems with short-ranged hopping, where diffusion coefficient usually {\it vanishes} and mobility remains finite.
Statistical Mechanics (cond-mat.stat-mech)
Tunable Itinerant Ferromagnetism in the Two-Dimensional FePd$_2$Te$_2$ Hosting 1D Spin Chains
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Alberto M. Ruiz, Andrei Shumilin, Sourav Dey, Diego López-Alcalá, José J.Baldoví
One-dimensional (1D) magnetism offers unidirectional spin interactions that allow unique tunable properties and unconventional spin phenomena. However, it often suffers from poor stability, limiting practical applications. In this regard, integrating 1D magnetism into two-dimensional (2D) materials enables a promising route to stabilize these systems while preserving their anisotropic magnetic characteristics. Here, we focus on the 2D ferromagnet FePd$ _2$ Te$ _2$ (T$ _C$ = 183K), which hosts 1D spin chains and strong in-plane anisotropy. Our first-principles calculations reveal highly anisotropic magnetic exchange interactions, confirming its 1D ferromagnetic nature. We modulate this behavior by Co and Ni substitution and introduce two new members of this family, CoPd$ _2$ Te$ _2$ – a ferromagnet – and NiPd$ _2$ Te$ _2$ . Our results unveil the microscopic mechanisms governing the behaviour of FePd$ _2$ Te$ _2$ and CoPd$ _2$ Te$ _2$ . Furthermore, we also demonstrate that the variation of the chain length is key to modulate magnetism. Finally, we determine the magnon dispersion, showcasing a pronounced anisotropy that enables unidirectional magnon propagation.
Materials Science (cond-mat.mtrl-sci)
Direct probe of magnetic field effects on phonons by ultrasound propagation in a quasi-two-dimensional honeycomb magnet Na$_2$Co$_2$TeO$_6$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-03 20:00 EDT
Xiaochen Hong, Maximilian Schiffer, Beat Valentin Schwarze, Marc Uhlarz, Xianghong Jin, Weiliang Yao, Lukas Janssen, Sergei Zherlitsyn, Bernd Büchner, Yuan Li, Young Sun, Christian Hess
We study the phonon behavior of a Co-based honeycomb frustrated magnet Na$ _2$ Co$ _2$ TeO$ _6$ under magnetic field applied perpendicular to the honeycomb plane. The temperature and field dependence of the sound velocity and sound attenuation unveil prominent spin-lattice coupling in this material, promoting ultrasound as a sensitive probe for magnetic properties. An out-of-plane ferrimagnetic order is determined below the Néel temperature $ T_N=27$ ~K. A comprehensive analysis of our data further provides strong evidence for a triple-Q ground state of Na$ _2$ Co$ _2$ TeO$ _6$ . Furthermore, the ultrasound data underscore that the field impact on the thermal conductivity as recently reported is of pure phononic origin.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Electrically tunable quantum interference of atomic spins on surfaces
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-03 20:00 EDT
Hao Wang, Jing Chen, Peng Fan, Yelko del Castillo, Alejandro Ferrón, Lili Jiang, Zilong Wu, Shijie Li, Hong-Jun Gao, Heng Fan, Joaquín Fernández-Rossier, Kai Yang
Controlling quantum interference near avoided energy-level crossings is crucial for fast and reliable coherent manipulation in quantum information processing. However, achieving tunable quantum interference in atomically-precise engineered structures remains challenging. Here, we demonstrate electrical control of quantum interference using atomic spins on an insulating film in a scanning tunneling microscope. Using bias voltages applied across the tunnel junction, we modulate the atomically-confined magnetic interaction between the probe tip and surface atoms with a strong electric field, and drive the spin state rapidly through the energy-level anticrossing. This all-electrical manipulation allows us to achieve Landau-Zener-Stückelberg-Majorana (LZSM) interferometry on both single spins and pairs of interacting spins. The LZSM pattern exhibits multiphoton resonances, and its asymmetry suggests that the spin dynamics is influenced by spin-transfer torque of tunneling electrons. Multi-level LZSM spectra measured on coupled spins with tunable interactions show distinct interference patterns depending on their many-body energy landscapes. These results open new avenues for all-electrical quantum manipulation in spin-based quantum processors in the strongly driven regime.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
Missing link between the 2D Quantum Hall problem and 1D quasicrystals
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-03 20:00 EDT
This paper discusses a connection between two important classes of materials, namely quasicrystals and topological insulators as exemplified by the Quantum Hall problem. It has been remarked that the quasicrystal ``inherits” topological properties from the 2D Quantum Hall model. We show this explicitly by introducing the Fibonacci-Hall model as a link between a 1D quasicrystal and the magnetic problems. We show here how Chern numbers for bands in periodic approximants of quasicrystals can be computed, along with gap labels. The Chern numbers are thus seen as a consequence of a flux parameter $ \phi^S$ induced by the geometry of winding in 2D space of the quasicrystal. We show the existence of lines of Lifshitz transitions in the phase space of the model. These are marked by change of Chern number and disappearance of edge states. The proposed extrapolation method can be generalized to higher dimensional 2D and 3D quasicrystals, where higher order Chern numbers could be computed, and related to experimentally measurable transport quantities.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
10 pages including 3 plus pages of Supplementary Information
Analogs of deconfined quantum criticality for non-invertible symmetry breaking in 1d
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-03 20:00 EDT
The spontaneous breaking of non-invertible symmetries can lead to exotic phenomena such as coexistence of order and disorder. Here we explore second-order phase transitions in 1d spin chains between two phases that correspond to distinct patterns of non-invertible symmetry breaking. The critical point shares several features with well-understood examples of deconfined quantum critical points, such as enlarged symmetry and identical exponents for the two order parameters participating in the transition. Interestingly, such deconfined transitions involving non-invertible symmetries allow one to construct a whole family of similar critical points by gauging spin-flip symmetries. By employing gauging and bosonization, we characterize the phase diagram of our model in the vicinity of the critical point. We also explore proximate phases and phase transitions in related models, including a deconfined quantum critical point between invertible order parameters that is enforced by a non-invertible symmetry.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech), High Energy Physics - Theory (hep-th), Quantum Physics (quant-ph)
16 pages, 4 figures, 1 table; main results are summarized in the Introduction
VO$_2$ oscillator circuits optimized for ultrafast, 100 MHz-range operation
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-03 20:00 EDT
Zsigmond Pollner, Tímea Nóra Török, László Pósa, Miklós Csontos, Sebastian Werner Schmid, Zoltán Balogh, András Bükkfejes, Heungsoo Kim, Alberto Piqué, Jeurg Leuthold, János Volk, András Halbritter
Oscillating neural networks are promising candidates for a new computational paradigm, where complex optimization problems are solved by physics itself through the synchronization of coupled oscillating circuits. Nanoscale VO$ _2$ Mott memristors are particularly promising building blocks for such oscillating neural networks. Until now, however, not only the maximum frequency of VO$ _2$ oscillating neural networks, but also the maximum frequency of individual VO$ _2$ oscillators has been severely limited, which has restricted their efficient and energy-saving use. In this paper, we show how the oscillating frequency can be increased by more than an order of magnitude into the 100 MHz range by optimizing the sample layout and circuit layout. In addition, the physical limiting factors of the oscillation frequencies are studied by investigating the switching dynamics. To this end, we investigate how much the set and reset times slow down under oscillator conditions compared to the fastest switching achieved with single dedicated pulses. These results pave the way towards the realization of ultra-fast and energy-efficient VO$ _2$ -based oscillating neural networks.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
12 pages, 7 figures
Direct determination of layer anomalous Hall conductivity using uniaxial Wannier functions
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Yume Morishima, Fumiyuki Ishii, Naoya Yamaguchi
We propose a method for computing layer anomalous Hall conductivity (LAHC) in real space by integrating the Fukui-Hatsugai-Suzuki method with hybrid Wannier functions localized along a single axis. To validate the method, we calculated the LAHC of axion-insulating MnBi$ _2$ Te$ _4$ and confirmed the agreement between the sum of LAHC on the surface and the surface AHC previously reported. We further applied the method to antiferromagnetic Mn$ _2$ Bi$ _2$ Te$ _5$ and examined the dependence on the magnetic structure of LAHC, identifying cases with and without axion insulating behavior. This layer-resolved analysis offers a powerful tool for studying topological transport in complex materials, including heterostructures, and may guide the design of future devices based on the anomalous Hall effect with precise layer control.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
16 pages, 3 figures
Controlled Spherulitic Crystal Growth from Salt Mixtures: A Universal Mechanism for Complex Crystal Self-Assembly
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-03 20:00 EDT
Tess Heeremans, Simon Lépinay, Romane Le Dizès Castell, Isa Yusuf, Paul Kolpakov, Daniel Bonn, Michael Steiger, Noushine Shahidzadeh
Spherulites are complex polycrystalline structures that form through the self-assembly of small aggregated nanocrystals starting from a central point and growing radially outward. Despite their wide prevalence and relevance to fields ranging from geology to medicine, the dynamics of spherulitic crystallization and the conditions required for such growth remain ill-understood. Here, we report on the conditions to induce controlled spherulitic growth of sodium sulfate from evaporating aqueous solutions of sulfate salt mixtures at room temperature. We reveal that introducing divalent metal ions in the solution cause spherulitic growth of sodium sulfate. For the first time, we quantify the supersaturation at the onset of spherulitic growth from salt mixtures and determine the growth kinetics. Our results show that the nonclassical nucleation process induces the growth of sodium sulfate spherulites at high supersaturation in highly viscous solutions. The latter reaches approximately 111 Pa$ \cdot$ s, triggered by the divalent ions, at the onset of spherulite precipitation leading to a diffusion limited growth. We also show that spherulites, which are metastable structures formed under out-of-equilibrium conditions, can evolve into other shapes when supersaturation decreases as growth continues at different evaporation rates. These findings shed light on the conditions under which spherulites form and offer practical strategies for tuning their morphology.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph), Geophysics (physics.geo-ph)
Superstrate structured Sb$_2$S$_3$ thin-film solar cells by magnetron sputtering of Sb and post-sulfurization
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Evgeniia Gilshtein, Harshvardhan Maheshkant Gupta, Andrea Maria Pierri Enevoldsen, Cristina Besleaga, Aurelian Catalin Galca, Stela Canulescu
We report on the fabrication and optimization of semi-transparent antimony sulfide (Sb$ _2$ S$ _3$ ) thin-film solar cells in a superstrate configuration, using RF magnetron sputtering of metallic antimony followed by post-deposition sulfurization. The influence of absorber and buffer layer thicknesses on device performance was systematically studied in FTO/CdS/Sb$ _2$ S$ _3$ /Spiro-OMeTAD/Au architectures. Optimizing the Sb$ _2$ S$ _3$ absorber thickness to 100 nm yielded a champion device with a power conversion efficiency of 2.76%, short-circuit current density of 14 mA/cm$ ^2$ , and open-circuit voltage of 650 mV. The devices exhibit up to 20% transmittance in the 380–740 nm wavelength range, indicating their suitability for indoor and building-integrated photovoltaic applications. Structural and compositional analyses confirmed high-purity Sb$ _2$ S$ _3$ (more than 90 at.%) and improved crystallinity after sulfurization. These results demonstrate the potential of sputtered Sb$ _2$ S$ _3$ as a scalable and tunable absorber for emerging transparent thin-film solar technologies and highlight the critical role of thickness optimization and interface control in device performance.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
Hyperspherical Analysis of Dimer-Dimer Scattering in One-Dimensional Systems
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-06-03 20:00 EDT
We present a comprehensive analysis of four-body scattering in one-dimensional (1D) quantum systems using the adiabatic hyperspherical representation (AHR). Focusing on dimer-dimer collisions between two species of fermions interacting via the sinh-cosh potential, we implement the slow variable discretization (SVD) method to overcome numerical challenges posed by sharp avoided crossings in the potential curves. Our numerical approach is benchmarked against exact analytical results available in integrable regimes, demonstrating excellent agreement. We further explore non-integrable regimes where no analytical solutions exist, revealing novel features such as resonant enhancement of the scattering length associated with tetramer formation. These results highlight the power and flexibility of the AHR+SVD framework for accurate few-body scattering calculations in low-dimensional quantum systems, and establish a foundation for future investigations of universal few-body physics in ultracold gases.
Quantum Gases (cond-mat.quant-gas), Atomic Physics (physics.atom-ph), Quantum Physics (quant-ph)
Time inversion symmetry in the Dirac and Schrödinger-Pauli theories
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
The Schrödinger-Pauli theory is generally believed to give a faithful representation of the nonrelativistic and weakly relativistic limit of the Dirac theory. However, the Schrödinger-Pauli theory is fundamentally incomplete in its account of broken time inversion symmetry, e.g., in magnetically ordered systems. In the Dirac theory of the electron, magnetic order breaks time inversion symmetry even in the nonrelativistic limit, whereas time inversion symmetry is effectively preserved in the Schrödinger-Pauli theory in the absence of spin-orbit coupling. In the Dirac theory, the Berry curvature $ 1/(2m^2c^2)$ is thus an intrinsic property of nonrelativistic electrons similar to the well-known spin magnetic moment $ e\hbar/(2m)$ , while this result is missed by the nonrelativistic or weakly relativistic Schrödinger-Pauli equation. In ferromagnetically ordered systems, the intrinsic Berry curvature yields a contribution to the anomalous Hall conductivity independent of spin-orbit coupling.
Materials Science (cond-mat.mtrl-sci), Quantum Physics (quant-ph)
3 pages, no figures
Adsorbate phase transitions on nanoclusters from nested sampling
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Thanawitch Chatbipho, Ray Yang, Robert B. Wexler, Livia B. Pártay
Nested sampling was employed to investigate adsorption equilibria on the truncated-octahedral Lennard-Jones nanocluster LJ$ _{38}$ while systematically varying adsorbate-surface well depth and Lennard-Jones size parameters. Evaluation of the canonical partition function over a wide temperature range identifies two successive phase transitions: (i) condensation of the gas phase onto the cluster surface at higher temperatures, and (ii) lateral rearrangement of the adsorbed layer at lower temperatures. For identical interactions, the condensate first populates both three- and four-fold hollow sites; when adsorbate-adsorbate interactions are weakened, preference shifts to the four-coordinated (100) sites. Size mismatch governs low-temperature behavior: smaller adsorbates aggregate to increase mutual contacts, whereas larger ones distribute more evenly to maximize coordination with the cluster. These findings highlight key trends in facet competition and lattice mismatch, and showcase nested sampling as an automated, unbiased tool for exploring surface configurational space and guiding investigations of more complex, realistic interfaces.
Materials Science (cond-mat.mtrl-sci), Statistical Mechanics (cond-mat.stat-mech), Chemical Physics (physics.chem-ph), Computational Physics (physics.comp-ph)
28 pages, 12 figures
Visualization of Co-3d high- and low-spin states in an Ising spin chain magnet
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-03 20:00 EDT
Kamini Gautam, Shunsuke Kitou, Yuiga Nakamura, Arvind Kumar Yogi, Dinesh Kumar Shukla, Taka-hisa Arima
Properties of trivalent cobalt oxide compounds are largely influenced by the spin state of the six 3d electrons at each Co site. High-spin Co3+ ions, where orbital angular momentum is only partially quenched, often exhibit significant anisotropy, providing playgrounds for Ising spin systems. However, real-space observations of their orbital states have remained limited. Here, we determine the Co-3d spin and orbital states in an Ising spin chain magnet Ca3Co2O6, where high- and low-spin states alternate along the chain. Synchrotron X-ray diffraction and valence electron density (VED) analysis, utilizing the core differential Fourier synthesis (CDFS) method, reveal distinct anisotropic VED distributions around the two Co sites with different symmetries. The VED distribution around the octahedral Co site corresponds to a low-spin state, while the trigonal-prismatic Co site exhibits anisotropic VED that cannot be explained by the crystal electric field (CEF) alone. This anisotropy is better reproduced by a model incorporating CEF, spin-orbit coupling, and on-site 3d-4p orbital hybridization, consistent with a high-spin state exhibiting Ising magnetism. These results provide deeper insight into Co-3d states and highlight the CDFS method’s utility in exploring interactions in quantum materials.
Strongly Correlated Electrons (cond-mat.str-el)
A continuum mechanics approach for the deformation of non-Euclidean origami generated by piecewise constant nematic director fields
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-03 20:00 EDT
We merge classical origami concepts with active actuation by designing origami patterns whose panels undergo prescribed metric changes. These metric changes render the system non-Euclidean, inducing non-zero Gaussian curvature at the vertices after actuation. Such patterns can be realized by programming piecewise constant director fields in liquid crystal elastomer (LCE) sheets. In this work, we address the geometric design of both compatible reference director patterns and their corresponding actuated configurations. On the reference configuration, we systematically construct director patterns that satisfy metric compatibility across interfaces. On the actuated configuration, we develop a continuum mechanics framework to analyze the kinematics of non-Euclidean origami. In particular, we fully characterize the deformation spaces of three-fold and four-fold vertices and establish analytical relationships between their deformations and the director patterns. Building on these kinematic insights, we propose two rational designs of large director patterns: one based on a quadrilateral tiling with alternating positive and negative actuated Gaussian curvature, and another combining three-fold and four-fold vertices governed by a folding angle theorem. Remarkably, both designs achieve compatibility in both the reference and actuated states. We anticipate that our geometric framework will facilitate the design of non-Euclidean/active origami structures and broaden their application in active metamaterials, soft actuators, and robotic systems.
Soft Condensed Matter (cond-mat.soft)
23 pages, 9 figures
Superconducting properties of ultrapure niobium
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-03 20:00 EDT
N. E. Alekseevskiy, V. I. Nizhankovskiy, K.-H. Bertel
The results of determination of critical magnetic fields, magnetization curves and critical currents of niobium samples of different purity are presented. It is shown that ultrapure niobium near Tc is a superconductor of the first type and becomes a superconductor of the second type with decreasing temperature due to the temperature dependence of the Ginzburg-Landau parameters. The dependence of the hysteresis of the magnetization curves of massive samples on the surface state is investigated. A comparison of the superconducting parameters with the parameters of the electron spectrum of niobium is carried out. The dependence of the critical current of niobium wires on the longitudinal magnetic field agrees with the assumption of a force-free current distribution.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci)
14 pages, 12 figures
A flexible and interoperable high-performance Lanczos-based solver for generic quantum impurity problems: upgrading EDIpack
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-03 20:00 EDT
Lorenzo Crippa, Igor Krivenko, Samuele Giuli, Gabriele Bellomia, Alexander Kowalski, Francesco Petocchi, Alberto Scazzola, Markus Wallerberger, Giacomo Mazza, Luca de Medici, Giorgio Sangiovanni, Massimo Capone, Adriano Amaricci
EDIpack is a flexible, high-performance numerical library using Lanczos-based exact diagonalization to solve generic quantum impurity problems, such as those introduced in Dynamical Mean-Field Theory to describe extended strongly correlated materials. The library efficiently solves impurity problems allowing for different broken-symmetry solutions, including superconductivity and featuring local spin-orbit coupling and/or electron-phonon coupling. The modular architecture of the software not only provides Fortran APIs but also includes bindings to C/C++, interfaces with Python and Julia or with TRIQS and W2Dynamics research platforms, thus ensuring unprecedented level of inter-operability. The outlook includes further extensions to study quantum materials and cold atoms quantum simulators, as well as quantum information applications.
Strongly Correlated Electrons (cond-mat.str-el), Computational Physics (physics.comp-ph)
75 pages, 8 figures, 7 examples
Floquet Möbius topological insulators
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-03 20:00 EDT
Longwen Zhou, Fan Zhang, Jiaxin Pan
Möbius topological insulators hold twofold-degenerated dispersive edge bands with Möbius twists in momentum space, which are protected by the combination of chiral and $ {\mathbb Z}_2$ -projective translational symmetries. In this work, we reveal a unique type of Möbius topological insulator, whose edge bands could twist around the quasienergy $ \pi$ of a periodically driven system and are thus of Floquet origin. By applying time-periodic quenches to an experimentally realized Möbius insulator model, we obtain interconnected Floquet Möbius edge bands around zero and $ \pi$ quasienergies, which can coexist with a gapped or gapless bulk. These Möbius bands are topologically characterized by a pair of generalized winding numbers, whose quantizations are guaranteed by an emergent chiral symmetry at a high-symmetry point in momentum space. Numerical investigations of the quasienergy and entanglement spectra provide consistent evidence for the presence of such Möbius topological phases. A protocol based on the adiabatic switching of edge-band populations is further introduced to dynamically characterize the topology of Floquet Möbius edge bands. Our findings thus extend the scope of Möbius topological phases to nonequilibrium settings and unveil a unique class of Möbius twisted topological edge states without static counterparts.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
16 pages, 9 figures
Sliding Ferroelectrics Induced Hybrid-Order Topological Phase Transitions
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Ning-Jing Yang, Jian-Min Zhang, Xiao-Ping Li, Zeying Zhang, Zhi-Ming Yu, Zhigao Huang, 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 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 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 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 material ScI2 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 experimentally probing.
Materials Science (cond-mat.mtrl-sci)
6 pages, 5 figures
Colloidal nanoparticles in cholesteric liquid crystals: Bulk properties, biaxiality and untwisting
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-03 20:00 EDT
Prabakaran Rajamanickam, Fatimah Almutari, Apala Majumdar
We study the effects of colloidal nanoparticles (NPs) in cholesteric liquid crystal samples in the dilute limit, in a Landau-de Gennes theoretical framework. The effects of the suspended NPs are captured by a homogenized energy, as outlined in [7]. For spatially homogeneous samples, we explicitly compute the critical points and minimizers of the modified Landau-de Gennes energy and show that the presence of NP eliminates the first-order isotropic-nematic phase transition, stabilises elusive biaxial phases over some temperature ranges, and that the symmetry of the NP boundary conditions or surface treatments dictates the bulk equilibrium phase at high temperatures. We also numerically demonstrate structural transitions from twisted helical director profiles to untwisted director profiles, in cholesteric-filled channel geometries, driven by the collective effects of the NPs and increasing temperature. These transitions are reversible upon lowering the temperature in sufficiently large domains, where thermal hysteresis can also be observed. This behaviour opens interesting avenues for tuning the optical properties of confined, nano-doped cholesteric systems.
Soft Condensed Matter (cond-mat.soft)
Switchable polarization in non-ferroelectric SrTiO$_3$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Wahib Aggoune, Matthias Scheffler
Perovskites with tunable and switchable polarization hold immense promise for unlocking novel functionalities. Using density-functional theory, we reveal that intrinsic defects can induce, enhance, and control polarization in non-ferroelectric perovskites, with SrTiO$ _3$ as our model system. At high defect concentrations, these systems exhibit strong spontaneous polarization - comparable to that of conventional ferroelectrics. Crucially, this polarization is switchable, enabled by the inherent symmetry-equivalence of defect sites in SrTiO$ _3$ . Strikingly, polarization switching not only reverses the polarization direction and modulates its magnitude but also modifies the spatial distribution of localized defect states. This dynamic behavior points to unprecedented responses to external stimuli, opening new avenues for defect-engineered materials design.
Materials Science (cond-mat.mtrl-sci)
Reply to the Comment on “Shell-Shaped Quantum Droplet in a Three-Component Ultracold Bose Gas”
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-06-03 20:00 EDT
In our work (Phys. Rev. Lett. 134, 043402 (2025)), we have proposed to realize a shell-shaped BEC with self-bound character in a three-component ($ 1,2,3$ ) Bose gas, where $ (2,3)$ and $ (1,2)$ both form quantum droplets and meanwhile are linked as core-shell structure. It was then commented in 2505.16554 that such structure is unstable against decaying to a dimer" configuration with lower energy, and moreover, it is most likely” impossible to be realized after releasing from the trap. In contrast to these claims, our reply shows that the core-shell and dimer states are energetically degenerate in the thermodynamic limit, and more importantly, the core-shell structure is robustly stable against external perturbations and can be realized practically following the trap-release scheme.
Quantum Gases (cond-mat.quant-gas)
2 pages, 3 figures. Reply to arXiv:2505.16554
Enhanced coherence and layer-selective charge order in a trilayer cuprate superconductor
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-03 20:00 EDT
S. Smit, M. Bluschke, P. Moen, N. Heinsdorf, E. Zavatti, G. Bellomia, S. Giuli, S.K.Y. Dufresne, C.T. Suen, V. Zimmermann, C. Au-Yeung, S. Zhdanovich, J.I. Dadap, M. Zonno, S. Gorovikov, H. Lee, C-T. Kuo, J-S. Lee, D. Song, S. Ishida, H. Eisaki, B. Keimer, M. Michiardi, I.S. Elfimov, G. Levy, D.J. Jones, M. Capone, A. Damascelli
Trilayer cuprates hold the record for the highest superconducting critical temperatures ($ T_{\text{c}}$ ), yet the underlying mechanism remains elusive. Using time- and angle-resolved photoemission spectroscopy (tr-ARPES), we uncover a striking interplay between charge order, superconducting gap magnitude, and quasiparticle coherence in Bi$ _2$ Sr$ _2$ Ca$ _2$ Cu$ _3$ O$ _{10+\delta}$ (Bi2223). This constitutes ARPES-based evidence of charge order on the inner CuO$ 2$ plane, as confirmed via resonant x-ray scattering (RXS); in addition, the same inner plane hosts a superconducting gap significantly larger than that of the overdoped outer planes, firmly establishing it as underdoped. Unexpectedly, despite its underdoped nature, the inner plane also exhibits an exceptional degree of quasiparticle coherence; suppressing charge-order fluctuations further enhances this, making it comparable to that of the overdoped outer planes at elevated electronic temperatures. These findings, supported by complementary three-layer single-band Hubbard calculations, reveal a unique interlayer mechanism in which both pairing strength and phase coherence are optimized when interfacing planes with distinct hole concentrations, providing new microscopic insight into the record $ T{\text{c}}$ of Bi2223.
Strongly Correlated Electrons (cond-mat.str-el)
Machine Learning-Guided Discovery of Temperature-Induced Solid-Solid Phase Transitions in Inorganic Materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Cibrán López, Joshua Ojih, Ming Hu, Josep Lluis Tamarit, Edgardo Saucedo, Claudio Cazorla
Predicting solid-solid phase transitions remains a long-standing challenge in materials science. Solid-solid transformations underpin a wide range of functional properties critical to energy conversion, information storage, and thermal management technologies. However, their prediction is computationally intensive due to the need to account for finite-temperature effects. Here, we present an uncertainty-aware machine-learning-guided framework for high-throughput prediction of temperature-induced polymorphic phase transitions in inorganic crystals. By combining density functional theory calculations with graph-based neural networks trained to estimate vibrational free energies, we screened a curated dataset of approximately 50,000 inorganic compounds and identified over 2,000 potential solid-solid transitions within the technologically relevant temperature interval 300-600 K. Among our key findings, we uncover numerous phase transitions exhibiting large entropy changes (> 300 J K$ ^{-1}$ kg$ ^{-1}$ ), many of which occur near room temperature hence offering strong potential for solid-state cooling applications. We also identify $ 21$ compounds that exhibit substantial relative changes in lattice thermal conductivity (20-70%) across a phase transition, highlighting them as promising thermal switching materials. Validation against experimental observations and first-principles calculations supports the robustness and predictive power of our approach. Overall, this work establishes a scalable route to discover functional phase-change materials under realistic thermal conditions, and lays the foundation for future high-throughput studies leveraging generative models and expanding open-access materials databases.
Materials Science (cond-mat.mtrl-sci)
20 pages, 7 figures
Tunable direct bandgap and optical response in \ch{Mo_{1-x}W_xS2} monolayer alloys: A first-principles investigation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Kevin Ndang Amassa, Jean-Pierre Tchapet Njafa, Anne Justine Etindele, Chetty Nithaya, Serge Guy Nana Engo
This study presents a comprehensive first-principles investigation of the structural, electronic and optical properties of monolayer \ch{Mo_{1-x}W_xS2} alloys, systematically exploring the full compositional range ($ x=0$ to $ 1$ ) using density functional theory (DFT). We establish that these alloys are thermodynamically stable and maintain the characteristic 2H crystal structure with minimal structural perturbation upon alloying. A key finding is the preservation of a direct bandgap at the $ K$ -point across all compositions. This gap exhibits continuous tunability, increasing near-monotonically from \SI{1.696}{\electronvolt} (\ch{MoS2}) to \SI{1.858}{\electronvolt} (\ch{WS2}), a critical feature for tailoring optoelectronic devices. Electronic structure analysis reveals the systematic evolution of the orbital contributions of transition metal $ d$ and sulfur $ p$ at the edges of the band with composition. Consequently, the optical spectra, evaluated up to \SI{8}{\electronvolt}, show a progressive blueshift in the main features of the interband transition with increasing \ch{W} content, accompanied by predictable changes in key optical constants. Our comprehensive results validate the monolayer \ch{Mo_{1-x} W_xS2} as an electronically versatile platform that offers fine control over electronic and optical properties via alloying, making these tunable direct-gap semiconductors highly promising for next-generation photodetectors, light emitters, and potentially flexible optoelectronic applications exploiting their 2D nature.
Materials Science (cond-mat.mtrl-sci), Quantum Physics (quant-ph)
16 pages, 13 figures
Persistence of charge ordering instability to Coulomb engineering in the excitonic insulator candidate TiSe$_2$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Sebastian Buchberger, Yann in ‘t Veld, Akhil Rajan, Philip A. E. Murgatroyd, Brendan Edwards, Bruno K. Saika, Naina Kushwaha, Maria H. Visscher, Jan Berges, Dina Carbone, Jacek Osiecki, Craig Polley, Tim Wehling, Phil D. C. King
TiSe$ _2$ has long been considered one of the best candidate materials to host the elusive excitonic insulator (EI) phase. However, a finite coupling to the lattice can generically be expected, while a lack of “smoking-gun” signatures for the importance of the electron-hole interaction in driving the phase transition has rendered it challenging to distinguish the EI from the conventional charge-density-wave (CDW) phase. Here, we demonstrate a new approach, exploiting the susceptibility of excitons to dielectric screening. We combine mechanical exfoliation with molecular-beam epitaxy to fabricate ultra-clean van der Waals heterostructures of monolayer (ML-)TiSe$ _2$ /graphite and ML-TiSe$ _2$ /hBN. We observe how the modified substrate screening environment drives a renormalisation of the quasi-particle band gap of the TiSe$ _2$ layer, signifying its susceptibility to Coloumb engineering. The temperature-dependent evolution of its electronic structure, however, remains unaffected, indicating that excitons are not required to drive the CDW transition in TiSe$ _2$ .
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
15 pages including supplemental information, 5+4 figures
Dependency of quantum time scales on symmetry
New Submission | Other Condensed Matter (cond-mat.other) | 2025-06-03 20:00 EDT
Fei Guo, Dmitrii Usanov, Eduardo B. Guedes, Mauro Fanciulli, Kaishu Kawaguchi, Ryo Mori, Takeshi Kondo, Arnaud Magrez, Michele Puppin, Hugo Dil
Although used extensively in everyday life, time is one of the least understood quantities in physics, especially on the level of quantum mechanics. Here we use an experimental method based on spin- and angle-resolved photoemission spectroscopy from spin-degenerate dispersive states to determine the Eisenbud-Wigner-Smith (EWS) time delay of photoemission. This time scale of the quantum transition is measured for materials with different dimensionality and correlation strength. A direct link between the dimensionality, or rather the symmetry of the system, and the attosecond photoionisation time scale is found. The quasi 2-dimensional transition metal dichalcogenides 1T-TiSe$ _2$ and 1T-TiTe$ _2$ show time scales around 150 as, whereas in quasi 1-dimensional CuTe the photoionisation takes more than 200 as. This is in stark contrast with the 26 as found for 3-dimensional pure Cu. These results provide new insights into the role of symmetry in quantum time scales and may provide a route to understanding the role of time in quantum mechanics.
Other Condensed Matter (cond-mat.other)
Unconventional Orbital Magnetism in Graphene-based Fractional Chern Insulators
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-03 20:00 EDT
Jian Xie, Zaizhe Zhang, Xi Chen, Yves H. Kwan, Zihao Huo, Jonah Herzog-Arbeitman, Liangliang Guo, Kenji Watanabe, Takashi Taniguchi, Kaihui Liu, X.C. Xie, B. Andrei Bernevig, Zhi-Da Song, Xiaobo Lu
Orbital magnetism in graphene originates from correlation-driven spontaneous valley symmetry breaking1-7. It can lead to various anomalous transport phenomena such as integer and fractional quantum anomalous Hall effects8-11. In general, the in-plane magnetic field B|| primarily couples to the spin degrees of freedom in graphene and has long been presumed to have a negligible effect on orbital magnetism due to the ultra-weak spin-orbit coupling12-18. In this work, we report multiple unconventional orbital magnetic phenomena that are highly sensitive to the B|| field in graphene/hBN superlattices hosting both integer and fractional Chern insulators (FCIs). We observed chirality-switching behaviors of the Chern insulator at moiré filling factor {\nu} = 1 under a finite B_par, demonstrating that both the C = +-1 states are permissible ground states at zero perpendicular magnetic field B_per. For the FCI at {\nu} = 2/3, we observed topological phase transitions between two states characterized by Hall resistivity \r{ho}xy = +-3h/2e2 under both B_per and B_par fields. In-plane B|| field can effectively suppress the FCI state at zero B_per field and enhance the FCI state with the opposite chirality, as resolved in Landau fan diagrams. Moreover, we observed rich phase transitions at 1 < {\nu} < 2, accompanied by intervalley coherence and anomalous Hall effects (AHE) that can be triggered by sweeping either B_per or B_par. Our work has unveiled new properties of orbital magnetism, providing a new knob for engineering various AHE in graphene.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
Linked skyrmions in shifted magnetic bilayer
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-03 20:00 EDT
Sumit Ghosh, Hiroshi Katsumoto, Gustav Bihlmayer, Moritz Sallermann, Vladyslav M. Kuchkin, Filipp N. Rybakov, Olle Eriksson, Stefan Blügel, Nikolai S. Kiselev
We present a shifted magnetic bilayer that exhibits various magnetic phases and magnetic textures with arbitrarily large topological numbers. The proposed system is characterised by a mutually orthogonal Dzyaloshinskii-Moriya interaction (DMI) in two different layers which can be induced by suitably placing non-magnetic atom with spin-orbit coupling. At weak interlayer coupling, the ground state resembles a checker-board pattern containing regions with unfavourable magnetic alignment which we call anti-aligned points. At finite interlayer coupling and finite external magnetic field, the bilayer can demonstrate a new class of magnetic solitons where multiple magnetic solitons can be connected by topological point defects which we call linked skyrmion. In addition to that the model also demonstrates conventional skyrmion-bags and $ k\pi$ -skyrmions. Finally, with rigorous first principle calculations, we propose a suitable material candidate where these magnetic configurations can be observed.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
6+2 pages, 5+2 figures
Deep learning of thermodynamic laws from microscopic dynamics
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-03 20:00 EDT
Hiroto Kuroyanagi, Tatsuro Yuge
We numerically show that a deep neural network (DNN) can learn macroscopic thermodynamic laws purely from microscopic data. Using molecular dynamics simulations, we generate the data of snapshot images of gas particles undergoing adiabatic processes. We train a DNN to determine the temporal order of input image pairs. We observe that the trained network induces an order relation between states consistent with adiabatic accessibility, satisfying the axioms of thermodynamics. Furthermore, the internal representation learned by the DNN act as an entropy. These results suggest that machine learning can discover emergent physical laws that are valid at scales far larger than those of the underlying constituents – opening a pathway to data-driven discovery of macroscopic physics.
Statistical Mechanics (cond-mat.stat-mech)
8 pages, 8 figures
Fully characterized linear magnetoelectric response of 2D monolayers from high-throughput first-principles calculations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
We screen 4784 stable monolayers from the Computational 2D Materials Database (C2DB) and identify 57 ferromagnetic (FM) and 67 antiferromagnetic (AFM) that should exhibit linear magnetoelectric (ME) effects. Using density functional theory, we compute contributions from the spin and orbital angular momentum as well as lattice-mediated and clamped-ion analogs to fully characterize the linear ME tensor in the static limit. We observe a general trend that AFM ordering gives rise to a larger ME response compared to FM ordered monolayers. Using a typical van der Waals interlayer distance, we find that AFM $ \mathrm{Mn}_2\mathrm{SI}_2$ exhibits the strongest component of linear ME response, providing approximately 580 ps/m. This is two orders of magnitude greater than in prototypical $ \mathrm{Cr}_2\mathrm{O}_3$ but comparable to the largest ME response measured in bulk $ \mathrm{TbPO}_4$ (280-740 ps/m). We also search for antimagnetoelectricity and find a number of FM and AFM compounds with antiferroic tensor entries. By demonstration of select examples and analysis of our full data set, we argue that inclusion of all contributions (spin, orbital, lattice-mediated and clamped-ion) is of crucial importance for reliable predictions of the total ME response.
Materials Science (cond-mat.mtrl-sci)
13 pages, 7 figures
Machine-learning-driven modelling of amorphous and polycrystalline BaZrS$_{3}$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Laura-Bianca Paşca, Yuanbin Liu, Andy S. Anker, Ludmilla Steier, Volker L. Deringer
The chalcogenide perovskite material BaZrS$ _{3}$ is of growing interest for emerging thin-film photovoltaics. Here we show how machine-learning-driven modelling can be used to describe the material’s amorphous precursor as well as polycrystalline structures with complex grain boundaries. Using a bespoke machine-learned interatomic potential (MLIP) model for BaZrS$ _{3}$ , we study the atomic-scale structure of the amorphous phase, quantify grain-boundary formation energies, and create realistic-scale polycrystalline structural models which can be compared to experimental data. Beyond BaZrS$ _{3}$ , our work exemplifies the increasingly central role of MLIPs in materials chemistry and marks a step towards realistic device-scale simulations of materials that are gaining momentum in the fields of photovoltaics and photocatalysis.
Materials Science (cond-mat.mtrl-sci)
Electronic structure reorganization in MPS3 via d-shell-selective alkali metal doping
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Jonah Elias Nitschke, Preeti Bhumla, Till Willershausen, Patrick Merisescu, David Janas, Lasse Sternemann, Michael Gutnikov, Karl Schiller, Valentin Mischke, Michele Capra, Mira Sophie Arndt, Silvana Botti, Mirko Cinchetti
Semiconducting two-dimensional (2D) antiferromagnetic (AFM) transition-metal thiophosphates (MPS3) offer promising opportunities for spintronic applications due to their highly tunable electronic properties. While alloying and intercalation have been shown to modulate ground states, the role of d-shell filling in governing these transitions remains insufficiently understood. Here, we investigate electron doping effects in MPS3 using angle-resolved photoemission spectroscopy (ARPES), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT+U). Lithium and cesium deposition are employed to induce doping across different MPS3 compounds. We identify two distinct doping mechanisms: in MnPS3, electrons are primarily donated to the P2S6 ligand clusters, with negligible Mn 2p core-level shifts and no major changes in the valence band. In contrast, FePS3, CoPS3, and NiPS3 exhibit clear reductions in transition-metal oxidation states, with a 1.0 eV reduction in spin-orbit splitting for Co upon doping. ARPES on CoPS3 reveals a 400 meV shift of Co-derived bands towards higher binding energies and new dispersive states up to 1 eV above the valence band maximum, indicating metallic behavior. These results establish a direct correlation between d-shell filling and doping response, highlighting alkali metal doping as a tunable route to tailor the electronic and magnetic properties of 2D AFM semiconductors for spintronic applications.
Materials Science (cond-mat.mtrl-sci)
Eta-pairing states in Hubbard models with bond-charge interactions on general graphs
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-03 20:00 EDT
We investigate Hubbard models with bond-charge interactions on general graphs. For a Hamiltonian (H) of such a model, we provide the condition on its parameters under which the (\eta)-pairing method can be employed to construct its exact eigenstates. We arrive at this condition by finding that the requirement for the (\eta)-pairing state ((\eta^\dagger)^N |0\rangle) to be an eigenstate of (H) is identical to the requirement for it to be an eigenstate of a Hubbard-type Hamiltonian (H_m). When the condition for ((\eta^\dagger)^N |0\rangle) to be an eigenstate of the Hubbard-type Hamiltonian (H_m) is satisfied, we demonstrate that there are additional states, distinct from ((\eta^\dagger)^N |0\rangle), which are also exact eigenstates of (H_m). Our results enhance the understanding of Hubbard models on general graphs, both with and without bond-charge interactions.
Strongly Correlated Electrons (cond-mat.str-el)
5 pages, 0 figures
Unlocking the hybrid piezo and pyroelectric nanogenerators performance by SiO2 nanowires confinement in poly(vinylidene fluoride)
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Juan Delgado-Alvarez, Hari Krishna Mishra, Francisco J. Aparicio, Xabier Garcia-Casas, Angel Barranco, Juan R. Sanchez-Valencia, Victor Lopez-Flores, Ana Borras
We report on the development of a novel flexible piezo/pyro-electric nanogenerator (PPNG) that combines a uniform film of poly(vinylidene fluoride) (PVDF) infiltrated over vertically supported SiO2 nanowires (NWs) to enhance both piezoelectric and pyroelectric energy harvesting capabilities. The synthetic procedure involves a low-temperature multi-step approach, including the soft-template formation of SiO2 NWs on a flexible substrate, followed by the infiltration of a PVDF thin film (TF). The plasma-enabled fabrication of SiO2 NWs facilitated vertical alignment and precise control over the surface microstructure, density, and thickness of the confined nanostructures. These strategic structural systems promote the development of the most favourable electroactive \b{eta}- and {\gamma}-phases in the PVDF matrix. Notably, the electrical poling plays a major role in aligning the random dipoles of the PVDF macromolecular chain in a more ordered fashion to nucleate the amplified electroactive phases. As a proof-of-concept, the fabricated PPNG exhibited a significant improvement in the instantaneous piezoelectric output power density (P), ~ 9-fold amplification relative to its bare PVDF TF counterpart. Analogously, the pyroelectric coefficient (p) demonstrated a 4-fold superior performance with referenced PVDF TF based PPNG. Thus, the engineered system of SiO2 NWs@PVDF comprising PPNG offers a promising pathway toward multisource energy harvesting capabilities through efficient energy transduction at mechanical excitation frequencies of 10-12 Hz and across a temperature difference ({\Delta}T) of 9 to 22 K.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph), Plasma Physics (physics.plasm-ph)
21 pages, 5 figures
Unfolding the kagome lattice to improve understanding of ARPES in CoSn
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-03 20:00 EDT
Véronique Brouet, Aaditya Vedant, Francois Bertran, Patrick Le Fèvre, Oleg Rubel
Metallic kagome lattices are attracting significant attention as they provide a platform to explore the interplay between topology and magnetism. Angle-resolved photoemission spectroscopy (ARPES) plays a key role in unraveling their electronic structure. However, the analysis is often challenging due to the presence of multiple bands near the Fermi level. Indeed, each orbital generates three bands in a kagome lattice due to its three inequivalent sites, which soon becomes complicated if many orbitals are present. To address this complexity, using ARPES matrix elements can be highly beneficial. First, band symmetry can be determined through selection rules based on light polarization. We emphasize that, in kagome lattices, symmetry is not only determined by the orbital character but also by the relative phase between the three sublattices. Additionally, interference between the three sublattices leads to a strong modulation of ARPES intensity across neighboring Brillouin zones. We show how unfolded band calculations capture these modulations, helping with band identification. We apply these ideas to CoSn, whose simple structure retains the key features of a kagome lattice. Taking advantage of these two effects, we isolate the dispersion of each band and discuss novel correlation effects, selectively renormalizing the bands crossing the Fermi level and shifting the others.
Strongly Correlated Electrons (cond-mat.str-el)
An Open and Collaborative Database of Properties of Materials for High-Temperature Superconducting-Based Devices
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-03 20:00 EDT
Pablo Cayado, João Rosas, João Murta-Pina, Harold S. Ruiz
The successful integration of high-temperature superconductors (HTS) into modern technologies requires consistent, accessible, and comprehensive material data, a need that is currently unmet due to the fragmented and incomplete nature of existing resources. This paper introduces a new collaborative, open-access database specifically designed to address this gap by providing standardized data on HTS materials and crucial auxiliary components for HTS applications. The database encompasses extensive data on structural, cryogenic, electrical, magnetic, and superconducting materials, supporting diverse requirements from HTS modelling to magnet design. Developed through collaborative efforts and organized using an ontology-driven data model, this platform is dynamically adaptable, ensuring that it can grow as new materials and data emerge. Key features include user-driven contributions, peer-reviewed data validation, and advanced filtering capabilities for efficient data retrieval. This innovative database, to the knowledge of the authors, being the largest publicly available for material properties of HTS technologies is positioned as a valuable tool for the HTS community, promoting more efficient research and development processes, accelerating the practical application of HTS, and fostering a collaborative approach to knowledge sharing within the field. The database is available at this https URL.
Superconductivity (cond-mat.supr-con), Applied Physics (physics.app-ph), Data Analysis, Statistics and Probability (physics.data-an)
The database is available at this https URL
IEEE Transactions on Applied Superconductivity
Realization of broken inversion symmetry in the charge density wave phase in EuAl$_4$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-03 20:00 EDT
Surya Rohith Kotla (1), Leila Noohinejad (2), Preeti Pokhriyal (2), Martin Tolkiehn (2), Harshit Agarwal (1 and 3), Sitaram Ramakrishnan (4), Sander van Smaalen (1) ((1) Laboratory of Crystallography, Bayerisches Geoinstitut, University of Bayreuth, Germany, (2) Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany, (3) Institut für Physik, Johannes-Gutenberg-Universität Mainz, Germany, (4) Institut Néel CNRS/UGA UPR2940, Grenoble, France)
EuAl$ 4$ exhibits a complex phase diagram, including the development of a charge density wave (CDW) below $ T{CDW} = 145$ K. Below $ T_{N}=15.4$ K, a series of antiferromagnetically (AFM) ordered phases appear, while non-trivial topological phases, like skyrmion lattices, are stabilized under an applied magnetic field. The symmetries of the variously ordered phases are a major issue concerning the understanding of the stabilization of the ordered phases as well as concerning the interplay between the various types of order. EuAl$ _4$ at room temperature has tetragonal symmetry with space group $ I4/mmm$ . The CDW phase has an incommensurately modulated crystal structure described by the modulation wave vector $ \mathbf{q} \approx 0.17,\mathbf{c}^{\ast}$ . On the basis of various experiments, including elastic and inelastic x-ray scattering, and second-harmonic generation, it has been proposed that the symmetry of the CDW phase of EuAl$ _4$ could be centrosymmetric orthorhombic, non-centrosymmetric orthorhombic or non-centrosymmetric tetragonal. Here, we report temperature-dependent, single-crystal x-ray diffraction experiments that show that the CDW is a transverse CDW with phason disorder, and with non-centrosymmetric symmetry according to the orthorhombic superspace group $ F222(0,0,\sigma)00s$ .Essential for this finding is the availability of a sufficient number of second-order ($ 2\mathbf{q}$ ) satellite reflections in the x-ray diffraction data set. The broken inversion symmetry implies that skyrmions might form due to Dzyaloshinskii-Moriya (DM) interactions, instead of a more exotic mechanism as it is required for centrosymmetric structures.
Strongly Correlated Electrons (cond-mat.str-el), Other Condensed Matter (cond-mat.other)
Loop current order on the kagome lattice
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-03 20:00 EDT
Jun Zhan, Hendrik Hohmann, Matteo Dürrnagel, Ruiqing Fu, Sen Zhou, Ziqiang Wang, Ronny Thomale, Xianxin Wu, Jiangping Hu
Recent discoveries in kagome materials have unveiled their capacity to harbor exotic quantum states, including intriguing charge density wave (CDW) and superconductivity. Notably, accumulating experimental evidence suggests time-reversal symmetry (TRS) breaking within the CDW, hinting at the long-pursued loop current order (LCO). Despite extensive research efforts, achieving its model realization and understanding the mechanism through unbiased many-body simulations have remained both elusive and this http URL this work, we develop a microscopic model for LCO on the spinless kagome lattice with non-local interactions, utilizing unbiased functional renormalization group calculations to explore ordering tendencies across all two-particle scattering channels. At the van Hove filling, we identify sublattice interference to suppress onsite CDW order, leaving LCO, charge bond and nematic CDW state as the main competitors. Remarkably, a $ 2\times2$ LCO emerges as the many-body ground state over a significant parameter space with strong second nearest-neighbor repulsion, stemming from the unique interplay between sublattice characters and lattice geometry. The resulting electronic model with LCO bears similarities to the Haldane model and culminates in a quantum anomalous Hall state. We also discuss potential experimental implications for kagome metals.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
7 pages, 4 figures
Anomalous non-thermal fixed point in a quasi-two-dimensional dipolar Bose gas
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-06-03 20:00 EDT
Niklas Rasch, Lauriane Chomaz, Thomas Gasenzer
The emergence of distinctly sub-diffusive scaling in the vicinity of an anomalous non-thermal fixed point is discussed in a quasi-two-dimensional dipolar Bose gas in the superfluid phase, carrying ensembles of vortices and antivortices with zero net angular momentum. The observed scaling behavior reflects coarsening dynamics driven by the mutual annihilation of vortices and antivortices, with the mean inter-defect distance growing algebraically over time as $ \ell_\text{v}(t)\sim t^{,\beta}$ . A sub-diffusive ($ \beta<1/2$ ) exponent $ \beta\approx0.2$ is extracted for various parameter regimes, initial conditions, and dipolar configurations from both scaling occupation-number spectra and the evolution of inter-defect distances as well as the corresponding total vortex densities. As vortex-antivortex annihilation progresses, excitations of the background condensate increase. This gives rise to a transition in the scaling behavior at late times, toward a non-thermal fixed point governed by diffusion-type scaling with $ \beta\approx1/2$ as expected for the mutual annihilation of well-separated vortex-antivortex dipoles. While the temporal scaling with $ \beta$ does not depend significantly on the strength and anisotropy of the dipolar interactions and thus underlines the universality of the anomalous as well as diffusion-type non-thermal fixed points, we find distinctly different vortex patterns resulting in the dipolar case. While in the superfluid with contact interactions only, same-sign vortices tend to cluster and form large-scale eddies, in the dipolar and tilted cases, roton excitations appear to prevent such motion, giving rather rise to a maximisation of distances between vortices of either sign.
Quantum Gases (cond-mat.quant-gas), High Energy Physics - Phenomenology (hep-ph)
20 pages, 11 figures
Overcoming Data Scarcity in Scanning Tunnelling Microscopy Image Segmentation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Nikola L. Kolev, Max Trouton, Filippo Federici Canova, Geoff Thornton, David Z. Gao, Neil J. Curson, Taylor J. Z. Stock
Scanning tunnelling microscopy (STM) is a powerful technique for imaging surfaces with atomic resolution, providing insight into physical and chemical processes at the level of single atoms and molecules. A regular task of STM image analysis is the identification and labelling of features of interest against a uniform background. Performing this manually is a labour-intensive task, requiring significant human effort. To reduce this burden, we propose an automated approach to the segmentation of STM images that uses both few-shot learning and unsupervised learning. Our technique offers greater flexibility compared to previous supervised methods; it removes the requirement for large manually annotated datasets and is thus easier to adapt to an unseen surface while still maintaining a high accuracy. We demonstrate the effectiveness of our approach by using it to recognise atomic features on three distinct surfaces: Si(001), Ge(001), and TiO$ _2$ (110), including adsorbed AsH$ _3$ molecules on the silicon and germanium surfaces. Our model exhibits strong generalisation capabilities, and following initial training, can be adapted to unseen surfaces with as few as one additional labelled data point. This work is a significant step towards efficient and material-agnostic, automatic segmentation of STM images.
Materials Science (cond-mat.mtrl-sci), Artificial Intelligence (cs.AI)
Strain-Induced Modulation of Spin Splitting and Persistent Spin Textures in Low-Symmetry 2D Hybrid Perovskites: A case study of RP phase
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Shantanu Pathak, Saswata Bhattacharya
We report the observation of a persistent spin texture (PST) in pseudo-2D hybrid perovskite, characterized by significant spin splitting strength on the order of (3 , \text{eV} \cdot \textÅ). Using first-principles density functional theory (DFT) calculations, complemented by a (\mathbf{k} \cdot \mathbf{p}) model analysis, we validate the presence of PST and its robustness under various conditions. The material’s non-centrosymmetric nature and strong spin-orbit coupling ensure uniform spin orientation in momentum space, enabling long spin lifetimes and promising spintronic applications. Furthermore, we demonstrate the tunability of the spin splitting via the application of external strain and stress, offering a versatile approach to control spin configurations. Our results highlight the potential of this perovskite system for next-generation spintronic devices, where external perturbations can be used to precisely modulate electronic properties.
Materials Science (cond-mat.mtrl-sci)
9 pages, 5 figures
Unconventional Superconducting Pairing Symmetries in La$_3$Ni$_2$O$_7$: from the Perspective of Topology
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-03 20:00 EDT
Guan-Hao Feng, Jun Quan, Yusheng Hou
The recently discovered superconductor La$ 3$ Ni$ 2$ O$ 7$ has attracted significant attention due to its remarkably high $ T{c}$ and unconventional pairing mechanism. High-pressure experiments have demonstrated that the emergence of the superconducting phase is associated with a transition to a higher-symmetry structure. Motivated by this observation, we investigate superconductivity in La$ 3$ Ni$ 2$ O$ 7$ under high pressure from the perspectives of symmetry and topology. Based on a bilayer two-orbital model with Ni-$ d{3z^{2}-r^{2}}$ and $ d{x^{2}-y^{2}}$ orbitals, we systematically examine all symmetry-allowed multi-orbital superconducting pairings at the Bogoliubov-de Gennes (BdG) mean-field level, including terms up to next-nearest neighbors. By solving the self-consistent gap equations and analyzing the BdG condensation energies, we find that the $ A{1g}$ pairing channel is the most probable one. The dominant pairing is $ s{\pm}$ -wave, originating from the intra-orbital interaction of the bilayer Ni-$ d{3z^{2}-r^{2}}$ orbital, while the subdominant pairing is $ d_{x^{2}-y^{2}}$ -wave, arising from the inter-orbital interactions between the $ d_{3z^{2}-r^{2}}$ and $ d_{x^{2}-y^{2}}$ orbitals. Furthermore, we implement the theory of symmetry indicator to reveal the topological characteristics of each pairing channel, demonstrating that the pairing symmetries can be identified by their distinct topological features.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
Micelle Forming Linear-Dendritic Block Copolymers: A Theoretical Comparison between Random Hyperbranched and Precise Dendrimer Polymer Architectures
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-03 20:00 EDT
Marios Giannakou, Oleg V. Borisov, Friederike Schmid
Hyperbranched block copolymers offer a simpler and more efficient synthesis route compared to more traditional dendritic systems, while still providing exceptional control over surface functionality and self-assembly. This makes them ideal candidates for engineering nanoparticles with tailored properties for applications such as drug delivery and sensing. Here we use self-consistent field calculations to compare the micelle structures formed by copolymers with a polydisperse hyperbranched (LHBC), monodisperse dendritic (LDBC), and linear solvophilic blocks. Representative LHBC structures were generated by molecular dynamics simulations mimicking the slow-monomer addition protocol. We find that LHBC micelles are more stable, have a lower critical micelle concentration, and are better at accommodating larger drug payloads than LDBC micelles, and these properties further improve with increasing polydispersity. LHBC micelles also offer more terminal ends for functionalization than LDBC micelles for LDBCs with up to four branching generations, with the number of terminal ends being surprisingly independent of the LHBC polydispersity. Our findings highlight the superiority of LHBC micelles in flexibility and performance over LDBC micelles.
Soft Condensed Matter (cond-mat.soft), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Statistical Mechanics (cond-mat.stat-mech), Chemical Physics (physics.chem-ph)
Infinite symmetry prevents disorder-induced localization in 2D
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-03 20:00 EDT
We show that 2D gapped many-body quantum states are constrained by an infinite-dimensional symmetry which renders them transparent to weak disorder. This prevents disorder-induced localization when interactions are strong enough to open a gap. Using purely algebraic methods we derive all possible quantum states near the superconductor-to-insulator (SIT) transition and we compute the meson spectrum of superinsulators.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Physical Review B111, 245101 (2025)
Superconducting gaps revealed by STM measurements on La2PrNi2O7 thin films at ambient pressure
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-03 20:00 EDT
Shengtai Fan, Mengjun Ou, Marius Scholten, Qing Li, Zhiyuan Shang, Yi Wang, Jiasen Xu, Huan Yang, Ilya M. Eremin, Hai-Hu Wen
The recent discovery of superconductivity in nickelate systems has generated tremendous interests in the field of superconductivity. The superconducting transition temperature above 80 K in La3Ni2O7 under pressure and the coexisting spin excitations certainly categorize the nickelate superconductors as unconventional. The core issue to understand the superconductivity mechanism is about the superconducting gap and its symmetry. By using the substrate of SrLaAlO4(00l), we have successfully synthesized the superconducting thin film of La2PrNi2O7 with Tc(onset) = 41.5 K. Superconducting tunneling spectra are successfully measured on the terraces after we remove the surface layer and expose the superconducting layer by using the tip-excavation technique. The spectrum shows a two-gap structure with Delta1 = 19 meV, Delta2 = 6 meV, and fittings based on the Dynes model indicate that the dominant gap should have an anisotropic s-wave structure, and the pure d-wave model fails to fit the data. Thus, our data put the priority in selecting the s+- among the two arguable pairing models: s+- and d-wave. Assuming the dominant interlayer superconducting gap, we obtain its magnitude to be Delta(perp) = 13 meV, while the intralayer gap Delta(para) is about 6 meV. Our results shed new light in understanding the mystery of superconductivity in bilayer nickelate superconductors.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
30 pages, 4 figures for main-text, 4 figures for Extended data and Supplementary Information
Comment on “Neutron diffraction evidence of the 3-dimensional structure of Ba2MnTeO6 and misidentification of the triangular layers within the face-centred cubic lattice”
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-03 20:00 EDT
J. Khatua, T. Arh, Shashi B. Mishra, H. Luetkens, A. Zorko, B. Sana, M. S. Ramachandra Rao, B. R. K. Nanda, P. Khuntia
Frustrated magnetism continues to attract significant attention due to its potential to host novel quantum many-body phenomena and associated exotic excitations that transcend existing paradigms. Herein, we present our reply to the comment on our recent thermodynamic and muon spin relaxation studies on a frustrated double perovskite, Ba2MnTeO6 (henceforth BMTO). Previous studies by four independent groups, including our group, suggested a trigonal space group based on single-crystal and polycrystalline samples of BMTO, while the recent comment reports a cubic space group based on polycrystalline samples. We believe that the structure is fairly intricate because of the slight variations between the two space groups, refining the crystal structure of BMTO remains an unresolved problem that needs additional high-resolution XRD and neutron diffraction studies on high-quality single crystals. It is thought, however, that structural assignments will not greatly influence any of the primary findings related to the magnetism and spin dynamics of BMTO. These consist of a magnetic phase transition at around 21 K, the observation of antiferromagnetic magnon excitations exhibiting a gap of 1.4 K beneath the phase transition, the presence of short-range spin correlations well above the antiferromagnetic phase transition, and the persistence of spin dynamics even within the magnetically ordered phase. It is important to note that the magnetization, specific heat, and muon spin relaxation findings that constitute the core of our earlier study are independent; the interpretation of these findings did not rely on any specific space group. Concerning the final allocation of the symmetry of BMTO, a definitive differentiation in certain physical characteristics resulting from the symmetry is still necessary.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Comment on arXiv:2202.03850
Superconducting diode effect in a meso-wedge geometry with Abrikosov vortices
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-03 20:00 EDT
C. A. Aguirre, J. Barba-Ortega, A. S. de Arruda, J. Faundez
In this study, we explore the behavior of a superconducting meso-wedge geometry in 3+1 dimensions (three spatial dimensions plus time) subjected to external transport currents at its boundaries and surfaces, as well as external fields applied along the $ \hat{z}$ -direction. The transport currents are included as two opposite polarities, $ \textbf{J}>0$ and $ \textbf{J}<0$ . Using the generalized time-dependent Ginzburg-Landau theory and considering the order parameter $ \kappa$ , we focus on two scenarios: a fixed external magnetic field with variable $ \kappa$ , and fixed $ \kappa$ with variable external magnetic field. As a result, under both scenarios, we analyze the voltage-current characteristics of the superconducting meso-wedge, finding that the critical currents differ between polarities, demonstrating the system’s non-reciprocity. We further examine the efficiency of the diode as a function of $ \kappa$ and the external magnetic field applied. Furthermore, our observations reveal that the current polarity strongly influences the vortex configuration, the parameter $ \kappa$ , and the applied magnetic field. In particular, the formation of Abrikosov-type vortices exhibits pronounced inhomogeneity depending on the direction of the transport currents. This underscores that the diode effect in the superconducting meso-wedge is intimately associated with the anisotropic nucleation of Abrikosov vortices. Notably, the emergence of polarity-dependent vortex patterns can serve as a distinctive hallmark of the diode effect in these superconducting systems.
Superconductivity (cond-mat.supr-con)
Electronic Temperature-Driven Phase Stability and Structural Evolution of Iron at High Pressure
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
We present Gibbs free-energy phase diagrams for compressed iron within a pressure range of 20 to 300 GPa and electronic temperature up to 3 eV obtained using finite-temperature density functional and density functional perturbation theories. Our results for bcc, fcc, and hcp phases predict solid-solid phase transitions in iron driven purely by electronic entropy and temperature. We found a phase transition from hcp to bcc at pressures above 200 GPa, which depends on the electronic temperature. An experimental observation of the stability of the bcc phase above 200 GPa by X-ray Free Electron Laser has recently been reported.
Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other), Computational Physics (physics.comp-ph), Geophysics (physics.geo-ph)
Inductive-Effect-Driven Tunability of Magnetism and Lumines-cence in Triangular Layers ANd(SO4)2 (A = Rb, Cs)
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Xudong Huai, Ebube E. Oyeka, Uchenna Chinaegbomkpa, Michal J. Winiarski, Hugo Sanabria, Thao T. Tran
Tuning the energy landscape of manybody electronic states in extended solids through the inductive effect-a concept widely used in organic chemistry-offers a new, effective strategy for materials development. Here, we demonstrate this approach using the ANd(SO4)2 (A = Rb, Cs) model system, which possesses different A-site electronegativity and displays a distorted triangular lattice of Nd3+ (4I9/2 ground term). Magnetization data indicate appreciable antiferromagnetic interactions without long-range ordering down to 1.8 K while highlighting the tunable population of the electronic states. Temperature-dependent and time-resolved photoluminescence measurements reveal that emissions and nonradiative processes can be modified by the inductive effect at the atomic level. Heat capacity data confirm no magnetic ordering and add insight into the role of phonons in emission lifetime. Density functional theory calculations prove enhanced covalency in the Cs compound compared to the Rb counterpart while acknowledging the adjustable magnetic intralayer and inter-layer exchange pathways. These results demonstrate a viable framework for utilizing the inductive effect as an important knob for simultaneously dialing in magnetic, optical, and electronic properties in quantum materials.
Materials Science (cond-mat.mtrl-sci)
Phenomenology of altermagnets
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Altermagnets have recently emerged as a new class of magnetic materials sharing properties of both antiferromagnets and ferromagnets. Despite very small net magnetization, they show phenomena usually associated with ferromagnetism, such as the Faraday, Kerr and Anomalous Hall effects, resulting from the relativistic spin-orbit coupling, as well as the spin splitting of electron bands and Spin Hall Effect of non-relativistic origin. Spin space groups and magnetic multipoles are used to explain symmetry properties of altermagnets. Here, I show that the conventional phenomenological description in terms of a vector antiferromagnetic order parameter can be applied to all effects observed in altermagnets with collinear and non-collinear spin orders. I also discuss non-relativistic effects in non-altermagnets.
Materials Science (cond-mat.mtrl-sci)
12 pages, 1 figure
Pressure-induced structural disordering and anomalous pressure-volume behaviour in high-entropy zirconates
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
Yogendar Singh, Xinghua Su, Vivek Kumar, H. K. Poswal, K. K. Pandey, Pawan Kumar Kulriya
The ambient-temperature high-pressure behaviour of (La0.2Nd0.2Sm0.2Gd0.2Yb0.2)2Zr2O7 zirconate (HEZ) nanopowders with three different average particle sizes (25nm, ~45 nm and ~ 68nm) were studied using synchrotron X-ray diffraction (SR-XRD) measurements up to ~30 GPa. Smaller particle-size HEZ nanopowder (25 nm), synthesized at the lower sintering temperature, exhibits pure defect-fluorite (DF) phase, whereas larger particle-size HEZ nanopowders (~45nm and ~68nm), synthesized at the higher sintering temperature, exhibit mixture of DF and pyrochlore phase (PY). The phase fraction of the PY phase increases with sintering temperature and hence with the particle size. All the HEZ nanopowders exhibit stability of initial structures (DF and PY) up to ~ 30 GPa, though phase fraction of PY phase in larger particle-size HEZ nanopowders successively reduces with pressure which is concomitant with significant variation in ox48f fractional coordinate in PY phase. Both the phases in all the studied samples exhibit anomalous pressure-volume (P-V) behaviour between ~7 to 15 GPa. The anomaly decreases with increasing particle size of HEZ nanopowders. The variation of bond lengths and polyhedron volume with pressure suggests that the anomalous P-V behaviour and structural changes at high pressures are primarily due to the distortion of the polyhedrons in DF and PY structures in HEZ nanopowders.
Materials Science (cond-mat.mtrl-sci)
A Quantum-Inspired Conceptual Model of Collective Subjective Evaluation via Bloch Sphere Dynamics and Like-Polarization
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-03 20:00 EDT
We propose a conceptual quantum-inspired model to describe subjective evaluation processes such as taste testing or consumer preference scoring-through the continuous time evolution of cognitive states represented on the Bloch sphere. Unlike conventional quantum cognition models that rely on projective measurements and state collapse, our framework treats evaluation as a weak or generalized measurement, preserving quantum coherence during the act of judgment. The mental state of preference is modeled as a coherent superposition in a two-dimensional Hilbert space, with time evolution governed by a stimulus-dependent Hamiltonian H(t), which reflects the sensory or motivational impact of external input. The observed score (e.g., 0 to 10) corresponds to the squared amplitude projected onto the “like” basis without collapsing the underlying state. For group-level analysis, we introduce a novel metric called “like-polarization”, analogous to spin polarization, which quantifies the collective orientation of preferences. This model provides a physically motivated alternative to classical evaluation theories, offering insights into the reversibility, context-dependence, and temporal dynamics of human judgment. It further enables applications in behavioral science, affective computing, and the design of human-centered AI systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
15 pages,5 figures
Proximity-Induced Rashba Spin-Orbit Interaction in BaMnO$\text{3}|$KTaO$\text{3}$ Heterostructure for Antiferromagnetic Spintronics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-03 20:00 EDT
We investigate the emergence of Rashba-like spin-orbit interaction in the antiferromagnetic BaMnO$ _3|$ KTaO$ 3$ oxide heterostructure using density functional theory (DFT). The analysis of our charge transfer model based on electrostatic potential reveals a type-I band alignment and establishes the conditions under which the interface becomes conducting. Our calculations uncover pronounced linear Rashba splitting ($ \alpha{(1)}$ = 0.114eVÅ) in Mn 3$ d$ bands near the Fermi level, induced by proximity to Ta 5$ d$ orbitals of the KTO substrate. The heterostructure exhibits inversion asymmetry due to polar discontinuities at its $ p$ -type and $ n$ -type interfaces. Using three-dimensional band dispersions and projected spin textures along with isoenergetic contours obtained from DFT calculations, we confirm the linear Rashba nature of the spin-orbit coupling. Employing Monte Carlo simulations based on DFT-derived magnetic exchange interactions, we estimate a Néel temperature of approximately $ \sim 54 \mathrm{K}$ . Our results demonstrate a viable route to engineering strong spin-orbit coupling in centrosymmetric antiferromagnets for spintronics applications.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Enhancing van-Hove singularities in SrRuO$_3$ films by vacancy engineerings
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-03 20:00 EDT
Moon Hyoung Lee, Hyungwoo Lee, Jun-Won Rhim
Flat bands, characterized by their localized electronic states and van Hove singularities, provide an ideal platform for exploring many-body physics. However, transition metal oxides hosting flat bands are quite rare. In this study, we investigate the origin of the existing nearly flat bands (NFBs) in SrRuO$ _3$ thin films and demonstrate how to increase the number of them through structural modifications. Using a tight-binding model that replicates experimental band structures, we analyze the SrRuO$ _3$ monolayer, revealing the origin of its NFBs along the $ x$ and $ y$ directions. These NFBs arise from destructive interference stabilizing strip-type compact localized states. By introducing periodic Ru-site vacancies, additional NFBs are generated, classified as partial or complete, depending on their Brillouin zone coverage. The compact localized states associated with these NFBs are identified, providing insight into their physical origin. For a 4-layer SrRuO$ _3$ multilayer film, we uncover many partial NFBs along the $ \Gamma$ X and XM directions and reveal the distinct origin of their development. Our findings highlight the potential of engineering flat bands in SrRuO$ _3$ films, offering new opportunities for exploring correlated electronic phases and expanding the material platform for flat-band physics.
Strongly Correlated Electrons (cond-mat.str-el)
Flux Trapping Characterization for Superconducting Electronics Using a Cryogenic Widefield NV-Diamond Microscope
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-03 20:00 EDT
Rohan T. Kapur, Pauli Kehayias, Sergey K. Tolpygo, Adam A. Libson, George Haldeman, Collin N. Muniz, Alex Wynn, Nathaniel J. O’Connor, Neel A. Parmar, Ryan Johnson, Andrew C. Maccabe, John Cummings, Justin L. Mallek, Danielle A. Braje, Jennifer M. Schloss
Magnetic flux trapping is a significant hurdle limiting reliability and scalability of superconducting electronics, yet tools for imaging flux vortices remain slow or insensitive. We present a cryogenic widefield NV-diamond magnetic microscope capable of rapid, micron-scale imaging of flux trapping in superconducting devices. Using this technique, we measure vortex expulsion fields in Nb thin films and patterned strips, revealing a crossover in expulsion behavior between $ 10$ and $ 20~\mu$ m strip widths. The observed scaling agrees with theoretical models and suggests the influence of film defects on vortex expulsion dynamics. This instrument enables high-throughput magnetic characterization of superconducting materials and circuits, providing new insight for flux mitigation strategies in scalable superconducting electronics.
Superconductivity (cond-mat.supr-con), Applied Physics (physics.app-ph), Instrumentation and Detectors (physics.ins-det), Quantum Physics (quant-ph)
7 pages main text (5 figures), 3 pages supplementary information (3 figures)
Coarse-graining dynamics to maximize irreversibility
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-03 20:00 EDT
Qiwei Yu, Matthew P. Leighton, Christopher W. Lynn
In many far-from-equilibrium biological systems, energy injected by irreversible processes at microscopic scales propagates to larger scales to fulfill important biological functions. But given dissipative dynamics at the microscale, how much irreversibility can persist at the macroscale? Here, we propose a model-free coarse-graining procedure that merges microscopic states to minimize the amount of lost irreversibility. Beginning with dynamical measurements, this procedure produces coarse-grained dynamics that retain as much information as possible about the underlying irreversibility. In synthetic and experimental data spanning molecular motors, biochemical oscillators, and recordings of neural activity, we derive simplified descriptions that capture the essential nonequilibrium processes. These results provide the tools to study the fundamental limits on the emergence of macroscopic irreversibility.
Statistical Mechanics (cond-mat.stat-mech), Disordered Systems and Neural Networks (cond-mat.dis-nn), Biological Physics (physics.bio-ph), Quantitative Methods (q-bio.QM)
7 pages + Supplemental Material included as ancillary files
Magnetic correlations in the $SU(3)$ triangular-lattice $t$-$J$ model at finite doping
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-06-03 20:00 EDT
Annika Böhler, Fabian Grusdt, Annabelle Bohrdt
Quantum simulation platforms have become powerful tools for investigating strongly correlated systems beyond the capabilities of classical computation. Ultracold alkaline-earth atoms and molecules now enable experimental realizations of SU(N)-symmetric Fermi-Hubbard models, yet theoretical understanding of these systems, particularly at finite doping remains limited. Here we investigate the strong-coupling limit of the $ SU(3)$ symmetric Fermi-Hubbard model on the triangular lattice with dimensions up to $ 9\times9$ lattice sites across the full doping range. Using a three-flavor extension of Gutzwiller-projected hidden fermion determinant states (G-HFDS), a neural network based variational ansatz, we analyze two- and three-point spin-spin and spin-spin-hole correlations of the $ SU(3)$ Cartan generators. We further study binding energies for large periodic systems, and compare our results to the paradigmatic $ SU(2)$ square lattice equivalent, finding strikingly similar magnetic correlations, but enhanced binding energies. Our results provide a foundation for future exploration of doped SU(N) Mott insulators, providing valuable insights for both theoretical developments and quantum simulation experiments.
Quantum Gases (cond-mat.quant-gas), Disordered Systems and Neural Networks (cond-mat.dis-nn), Strongly Correlated Electrons (cond-mat.str-el)
5 pages, 4 figures
Statistical Interaction Driven Thermoelectricity and Violation of Wiedemann-Franz Law
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-03 20:00 EDT
Sampurna Karmakar, Amulya Ratnakar, Sourin Das
Quantum transport anomalies in systems obeying Haldane-Wu fractional exclusion statistics, characterized by the statistical interactions parameter $ g$ are investigated. We identify particle-hole symmetry breaking of the Haldane-Wu distribution function via its deviations of the maximum entropy ($ \mathcal{S}{g}^{max}$ ), evaluated at the chemical potential, from the value $ {k_B} \ln 2$ (a value that holds only at the free fermion limit, $ g=1$ ). A duality relation, $ g,\mathcal{S}{g}^{max}=\mathcal{S}_{1/g}^{max}$ , quantifying the degree of violation is obtained. This symmetry breaking manifests in transport phenomena as: significant violations of the Wiedemann-Franz law arising for $ g>1$ (but remain absent for $ g\leq 1$ ) across a broad temperature range. Moreover, the thermoelectric figure of merit $ ZT$ is substantially enhanced for $ g>1$ and suppressed for $ g<1$ , indicating new routes to optimize energy conversion. These results deepen the understanding of the interplay between equilibrium statistics and transport, suggesting avenues for engineering advanced thermoelectric materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
8 pages, 5 figures
Multi-mode NOON states generation with ultracold atoms via geodesic counterdiabatic driving
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-06-03 20:00 EDT
Dengis Simon, Sandro Wimberger, Peter Schlagheck
We present a protocol for the generation of NOON states with ultracold atoms, leveraging the Bose-Hubbard model in the self-trapping regime. By the means of an optimized adiabatic protocol, we achieve a significant reduction in the time required for the preparation of highly entangled NOON states, involving two or more modes. Our method saturates the quantum speed limit, ensuring both efficiency and high fidelity in state preparation. A detailed analysis of the geodesic counterdiabatic driving protocol and its application to the Bose-Hubbard system highlights its ability to expand the energy gap, facilitating faster adiabatic evolution. Through perturbation theory, we derive effective parameters that emulate the counterdiabatic Hamiltonian, enabling experimentally viable implementations with constant physical parameters. This approach is demonstrated to yield exponential time savings compared to standard geodesic driving, making it a powerful tool for creating complex entangled states for applications in quantum metrology and quantum information. Our findings pave the way for scalable and precise quantum state control in ultracold atomic systems.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)