Materials Science
Influence of Manganese Content on Plastic Deformation Mechanisms in Polycrystalline {\alpha}-Ti-Mn Alloys
G. Marković, M. Fedorov, M. Sokića et al. (+2 more)
Titanium
alloys are widely used in aerospace, biomedical, and energy applications owing to their high specific strength, corrosion resistance, and biocompatibility. Among them, $\alpha$-titanium
alloys with a hexagonal close-packed (hcp)
crystal structure exhibit characteristic deformation mechanisms governed by crystallographic slip and defect
evolution. In this study, the influence of manganese content on the plastic deformation mechanisms of polycrystalline $\alpha$-Ti-2Mn and $\alpha$-Ti-4Mn (at.%)
alloys is investigated using molecular dynamics simulations. Atomistic models were subjected to uniaxial loading at room temperature at a strain rate of 10$^9$ s$^{-1}$. The mechanical response was evaluated through stress-strain behavior, structural
evolution, dislocation nucleation and interaction, and analysis of the local deformation field. Plastic deformation in these $\alpha$-Ti-Mn
alloys is dominated by dislocation nucleation and their subsequent
evolution within the hcp
lattice. Increasing Mn content leads to higher stress levels and enhanced resistance to plastic deformation, accompanied by changes in dislocation activity and defect
evolution.
Read the full abstract ▾
All authors G. Marković, M. Fedorov, M. Sokića, K. Frydrych, F. J. Dominguez-Gutierrez
Materials Science
Grafted Low-Leakage Si/AlN p-n Diodes Enabled by Fluorinated AlN Interface
Yi Lu, Tsung-Han Tsai, Qingxiao Wang et al. (+19 more)
Ultrawide-bandgap AlN is a promising material for next-generation power electronics; however, its practical implementation is hindered by unstable surface chemistry and the high activation energy of p-type dopants. In particular, high-temperature rapid thermal annealing (RTA), required for forming low-resistance contacts on n-type AlN, leads to the formation of thick and defective surface
oxides that degrade heterojunction performance. In this work, we present an interface engineering approach based on fluorination-induced AlFx formation combined with SiNx passivation to suppress defect-assisted leakage in p-Si/n-AlN heterojunction diodes fabricated via
semiconductor grafting. A low-damage pseudo-atomic layer etching process is employed to remove RTA-induced
oxides and restore a near-stoichiometric AlN surface. Subsequent XeF2 treatment forms an ultrathin AlFx layer, which is stabilized by an atomic-layer-deposited SiNx capping layer prior to p-Si nanomembrane integration. Electrical measurements show that the engineered AlFx/SiNx interface reduces reverse leakage current by several orders of magnitude compared to untreated or
oxide-removed AlN surfaces, while preserving forward conduction characteristics. Temperature-dependent analysis indicates strong suppression of Poole-Frenkel emission and a shift of leakage onset to higher reverse bias, ultimately limited by bulk AlN
crystal quality. X-ray photoelectron spectroscopy and transmission electron microscopy confirm the formation of Al-F bonds, reduced Al-O content, and the presence of a thin interfacial SiOx/SiON layer. These results establish AlFx/SiNx passivation as an effective strategy for stabilizing AlN interfaces and enabling low-leakage ultrawide-bandgap heterojunction devices.
Read the full abstract ▾
All authors Yi Lu, Tsung-Han Tsai, Qingxiao Wang, Haicheng Cao, Jie Zhou, You Jin Koo, Chenyu Wang, Yang Liu, Yueyue Hao, Michael Eller, Connor Bailey, Stephanie Liu, Nicholas J. Tanen, Zhiyuan Liu, Mingtao Nong, Robert M. Jacobberger, Tien Khee Ng, Katherine Fountaine, Vincent Gambin, Boon S. Ooi, Xiaohang Li, Zhenqiang Ma
Mesoscale and Nanoscale Physics
Tunable Valley Polarization in Diamond
Nattakarn Suntornwipat, Jan Isberg and Saman Majdi
Device stability is essential for
quantum information technologies, where reliable control of electronic states is crucial. Diamond valleytronics offers a promising platform by exploiting the valley degree of freedom to store and manipulate information. In this work, we demonstrate a diamond-based valley transistor with a dual-gate, two-drain architecture that enables tunable valley-polarized transport via gate voltage modulation. By leveraging the significant effective-mass anisotropy of diamond's conduction band valleys, this architecture provides control over spatial distribution and transit times. We further demonstrate that valley-polarized transport in diamond is remarkably robust against thermal variations over macroscopic distances. These results demonstrate the resilience of valley states and highlight diamond's potential for energy-efficient valleytronic devices in next-generation
quantum and high-power electronics.
Read the full abstract ▾
Statistical Mechanics
Higher Nishimori Criticality and Exact Results at the Learning Transition of Deformed Toric Codes
Rushikesh A. Patil, Malte Pütz, Simon Trebst et al. (+2 more)
We revisit a learning-induced tricritical point, at which three phases with strong, weak, and broken $Z_2$
symmetry meet, in the phase diagram of a deformed toric code wavefunction subjected to weak measurements. This setting is exactly dual to a classical
Bayesian inference phase diagram of the $2D$ classical Ising model. Here we demonstrate that this tricritical point lies on a distinct $\textit{higher Nishimori line}$, which has an emergent gauge-invariant formulation, just like the ordinary Nishimori line but with a higher replica
symmetry as a replica stat-mech model in the replica number $R\rightarrow2$ limit, where disorder is averaged according to the Born rule. As such, the learning tricritical point is in fact a $\textit{higher Nishimori critical point}$. Using this identification, we obtain a number of $\textit{exact results}$ at this $\textit{higher}$ Nishimori critical point; e.g., we show that the power-law exponent of the Edwards-Anderson correlation function is exactly equal to that of the
spin correlation function at the unmeasured Ising critical point and verify this in numerical simulations. Using the tools of the proof of a $c$-effective
theorem [arXiv:2507.07959], we show that the Casimir effective central charge $c_{\text{eff}}$ $\textit{decreases}$ under renormalization group (RG) flow from the $\textit{higher}$ Nishimori critical point to the unmeasured $2D$ Ising critical point, and is thus greater than $1/2$. This is corroborated by extensive numerical simulations finding $c_{\text{eff}} = 0.522(1)$. The analytical result also explains, with a physically motivated assumption, the numerically observed increase of the Casimir effective central charge under the RG flow from the ordinary Nishimori critical point to the clean Ising critical point in the random-bond Ising model. We also discuss $\textit{higher}$ Nishimori criticality in general dimensions $D>1$.
Read the full abstract ▾
All authors Rushikesh A. Patil, Malte Pütz, Simon Trebst, Guo-Yi Zhu, Andreas W. W. Ludwig
Strongly Correlated Electrons
Crystallization in the Fractional Quantum Hall Regime with Disorder-Aware Neural Quantum States
Jihang Zhu, Yi Huang, Xiaodong Hu et al. (+2 more)
We present the first microscopic demonstration of a disorder-pinned hole Wigner
crystal (WC), providing a natural explanation for the reentrant integer
quantum Hall effect observed near $\nu=2/3$, as well as its analogs in fractional Chern
insulators. We further identify a novel crossover regime above filling $\nu=2/3$ that connects this hole WC to an electron WC, characterized by a network-like electron density structure. To uncover these phenomena, we use neural-network variational Monte Carlo (NNVMC) with a disorder-aware self-
attention neural
quantum state that describes both fractional
quantum Hall (FQH)
liquids and Wigner
crystals within a single unbiased variational framework. More broadly, our method establishes a unified phase diagram that exposes a fundamental asymmetry in crystallization across half-filling: near $\nu=1/3$, increasing LL mixing and disorder both stabilize an electron WC, whereas near $\nu=2/3$, the hole WC dominates at weak LL mixing and ultimately gives way to the electron WC at strong LL mixing.
Read the full abstract ▾
All authors Jihang Zhu, Yi Huang, Xiaodong Hu, Di Xiao, Ting Cao
Disordered Systems and Neural Networks
DYNAMITE: A high-performance framework for solving Dynamical Mean-Field Equations
Johannes Lang, Vincenzo Citro, Luca Leuzzi et al. (+1 more)
Understanding the dynamics of systems evolving in complex and rugged energy landscapes is central across physics, economics, biology, and computer science. Disordered mean-field models provide a powerful framework, as exact Dynamical Mean-Field Equations (DMFE) can be derived. However, solving the DMFE – a set of coupled integral-differential equations for two-time functions – remains a major numerical challenge. So far, large-time solutions of DMFE rely either on analytical approaches, such as the Cugliandolo–Kurchan ansatz based on assumptions like weak ergodicity breaking (which is known to fail in some cases), or on numerical integrations that reliably reach times $O(10^3)$ and extend further only via poorly controlled approximations. Consequently, no general method currently exists to solve DMFE at very long times, limiting the study of slow dynamics in complex landscapes. We present Dynamite (DYNAmical Mean-fIeld Time
Evolution solver), a high-performance framework for solving DMFE up to unprecedented times $t=O(10^7)$. It combines non-uniform interpolation, adaptive time stepping, and numerical `renormalization' of
memory, enabling accurate evaluation of history integrals. Its asymptotic runtime is linear, with sublinear
memory scaling. Stability and precision are ensured via an adaptive Runge–Kutta scheme and periodic sparsification of the past. Dynamite achieves orders-of-magnitude speedups over uniform-grid methods while maintaining accuracy and reproducibility on CPU and GPU architectures.
Benchmarks on glassy mean-field models, including the mixed spherical $p$-
spin system, demonstrate access to aging and relaxation regimes previously out of reach. The framework provides a reproducible and extensible foundation for studying long-
memory dynamical systems.
Read the full abstract ▾
All authors Johannes Lang, Vincenzo Citro, Luca Leuzzi, Federico Ricci-Tersenghi
Strongly Correlated Electrons · Cross-listed from hep-th
Zhiyao Lu, Sahand Seifnashri and Shu-Heng Shao
We present a solvable
Hamiltonian that realizes an exact
lattice chiral $U(1)_V \times U(1)_A$
symmetry. Nielsen-Ninomiya-type no-go
theorems are evaded by using
lattice bosons rather than
fermions. The continuum limit is a compact
boson field theory with an
axion-like coupling. The $U(1)_V$
symmetry shifts the scalar, while $U(1)_A$ acts on local operators associated with short
axion strings and is transmuted into a higher-form
symmetry in the continuum limit. We demonstrate the
chiral anomaly by showing that the
lattice theta angle is shifted by an axial rotation when $U(1)_V$ is gauged. Gauging either $U(1)_V$ or $U(1)_A$ leads to
lattice non-invertible and 2-group
symmetries, respectively, matching the continuum picture.
Read the full abstract ▾
Materials Science
Optoelectronic and Thermoelectric Properties of High-Performance AlSb Semiconductors
Dilshod Nematov, Amondulloi Burkhonzoda, Iskandar Raufov et al. (+6 more)
This study presents a comprehensive first-principles investigation of the optoelectronic and thermoelectric properties of aluminum antimonide (AlSb) in its cubic (F-43m) and hexagonal (P63mc) phases. Structural optimization was performed using the SCAN functional, and all electronic and optical properties were evaluated using the modified Becke-Johnson potential combined with the Hubbard correction (mBJ+U), which best describes the band-edge electronic structure, explicitly accounting for the contribution of the d-states of the Sb half-core, which cannot be adequately accounted for by conventional functionals and may be overestimated by hybrid approaches. Both AlSb phases are found to be quasi-direct bandgap
semiconductors, with calculated band gaps of 1.71 eV for the cubic phase and 1.50 eV for the hexagonal phase, in good agreement with available experimental data. The optical response reveals strong absorption in the visible and ultraviolet regions, moderate reflectivity, and high refractive indices, indicating pronounced light-matter interaction characteristic of III-V
semiconductors. The hexagonal phase exhibits enhanced low-energy optical absorption due to its reduced
symmetry and narrower band gap. Thermoelectric analysis demonstrates large negative Seebeck coefficients, thermally activated carrier generation, and a monotonic increase of the power factor with carrier concentration for both phases. The cubic phase shows higher power factor values due to enhanced carrier mobility, whereas the hexagonal phase benefits from reduced thermal conductivity, which is favorable for thermoelectric performance at elevated temperatures. These results establish AlSb as a multifunctional
semiconductor with tunable optoelectronic and thermoelectric properties and highlight the importance of an accurate treatment of Sb d-electron effects for reliable property prediction.
Read the full abstract ▾
All authors Dilshod Nematov, Amondulloi Burkhonzoda, Iskandar Raufov, Sherali Murodzoda, Saidjafar Murodzoda, Sakhidod Sattorzoda, Anushervon Ashurov, Makhsud Barot Islomzoda, Kholmirzo Kholmurodov
Statistical Mechanics · Cross-listed from cs.LG
SMT-AD: a scalable quantum-inspired anomaly detection approach
Apimuk Sornsaeng, Si Min Chan, Wenxuan Zhang et al. (+4 more)
Quantum-inspired tensor networks
algorithms have shown to be effective and efficient models for machine learning tasks, including anomaly detection. Here, we propose a highly parallelizable
quantum-inspired approach which we call SMT-AD from Superposition of Multiresolution Tensors for Anomaly Detection. It is based upon the superposition of bond-dimension-1
matrix product operators to transform the input data with
Fourier-assisted feature
embedding, where the number of learnable parameters grows linearly with feature size,
embedding resolutions, and the number of additional components in the
matrix product operators structure. We demonstrate successful anomaly detection when applied to standard
datasets, including credit card transactions, and find that, even with minimal configurations, it achieves competitive performance against established anomaly detection baselines. Furthermore, it provides a straightforward way to reduce the weight of the model and even improve the performance by highlighting the most relevant input features.
Read the full abstract ▾
All authors Apimuk Sornsaeng, Si Min Chan, Wenxuan Zhang, Swee Liang Wong, Joshua Lim, Jonathan Pan, Dario Poletti
Statistical Mechanics
Mutual Linearity in and out of Stationarity for Markov Jump Processes: A Trajectory-Based Approach
Jiming Zheng and Zhiyue Lu
Nonequilibrium response theory is a fundamental framework for understanding how physical systems respond to perturbations. Recently, a mutual linearity has been discovered for Markov jump processes using linear
algebra analysis. This mutual linearity states that two observables are linearly dependent on each other in the long-time limit when the transition rate of a single edge is altered. It has also been extended to non-stationary cases for current observables. In this work, we provide a trajectory-based derivation of mutual linearity utilizing the trajectory-level linear response theory. The trajectory approach allows us to generalize the mutual linearity to non-stationary relaxation dynamics for state observables and counting observables. Our results shed light on the fundamental response properties far from
equilibrium and the trajectory-level origin of mutual linearity. Our trajectory-based approach makes it possible to generalize the mutual linearity to a broader class of systems, including
diffusion processes and open
quantum systems.
Read the full abstract ▾
Strongly Correlated Electrons
Tractable model for a fractionalized Fermi liquid (FL$^*$) on a square lattice
Piers Coleman, Elio J. König, Aaditya Panigrahi et al. (+1 more)
Motivated by the continued interest in
Fermi-surface reconstruction without
symmetry breaking, we present an analytically tractable microscopic model of a fractionalized
Fermi liquid (FL$^*$) on a square
lattice and discuss its potential relevance to the cuprates. As in ancilla-
qubit constructions, the model is related to Kondo
lattice systems, but in this case, the conduction electrons interact with a $\mathbb{Z}_2$
spin liquid of the Yao–Lee type, with a Majorana
Fermi surface. The associated $\mathbb Z_2$ gauge theory is static so that the model can be analytically solved to leading-logarithic accuracy. There are two phases: one in which the fractionalized
fermions of the
spin liquid hybridize with conduction electrons to form a common
Fermi surface violating the naive Luttinger count, and one in which they remain decoupled. We discuss the salient features of the small
Fermi-surface phase, including analytically derived momentum dependent coherence factors responsible for the appearance of
Fermi arcs à la Yang-Rice-Zhang. We further discuss the impact of
quantum and thermal fluctuations, including a strong diamagnetic response and a logarithmically divergent Sommerfeld coefficient at the onset of the pseudogap.
Read the full abstract ▾
All authors Piers Coleman, Elio J. König, Aaditya Panigrahi, Alexei Tsvelik
Mesoscale and Nanoscale Physics
Solving the Peierls-Boltzmann transport equation with matrix product states
Sangyeop Lee, Hirad Alipanah and Juan José Mendoza-Arenas
The Peierls-Boltzmann transport equation (PBE), which governs non-
equilibrium phonon transport, suffers from the curse of dimensionality due to its high-dimensional phase space including both real and modal spaces. We explore the use of
matrix product states (MPS) for numerical simulation of the PBE. We show that an MPS configuration based on scattering events combined with a dimensionless form of the solution can drastically increase the locality of correlations between tensors in the MPS representation, enhancing its effectiveness in dimension reduction. We further examine the effects of index ordering in an MPS and find that the highest locality is achieved when tensor chains associated with both real and modal spaces are connected from the coarsest grid to each other in the center of the MPS. Using this optimal configuration and a solver inspired by the density
matrix renormalization group, we solve the PBE discretized by a finite volume method (FVM). The solution is obtained for crystalline silicon across ballistic, quasi-ballistic, and diffusive transport regimes. An MPS truncated to the compression ratio of $10^{-3}$ suffices to reproduce reference solutions with high fidelity. The computational cost scales sublinearly with the number of grid points in both real and modal spaces, achieving roughly an order of magnitude reduction in computational time compared to the FVM with sparse
matrix operation.
Read the full abstract ▾
Statistical Mechanics · Cross-listed from math.PR
REM universality for linear random energy
Francesco Concetti and Simone Franchini
We consider a sequence of random
Hamiltonians $H_n(h,\sigma)=\sum^n_{i=1}h_i(\sigma_i-m)$, and study the asymptotic ($n\to \infty$) distribution of the energy levels $(H_n(h,\sigma))_{\sigma\in \{-1,1\}^n}$, where $h_1,h_2,\cdots$ are i.i.d. random variables. We show that, when $e^{O(n)}$ configurations are sampled at random, the corresponding collection of energy levels converges in distribution to a Poisson point process with exponential intensity measure. This establishes the Random Energy Model (REM) universality for the present model. Our results strengthen earlier works on local REM universality by characterizing the distribution of $O(1)-$order fluctuations of $H_n$. In addition, we improve upon the REM universality by dilution studied by Ben Arous, Gayrard, Kuptsov by allowing an exponentially large number $e^{O(n)}$ of sampled configurations, instead of $e^{o(\sqrt{n})}$. Finally, we derive the asymptotic distribution of the Gibbs weight.
Read the full abstract ▾
Materials Science
Key Role of Charge Disproportionation in Monoclinic Semiconducting Fe$_2$PO$_5$, a Room-Temperature d-Wave Altermagnet Candidate
Zhen Zhang, Mohd Anas, Andrey Kutepov et al. (+2 more)
$\beta$-Fe$_2$PO$_5$ is an emerging room-temperature d-wave altermagnet featuring quasi-one-dimensional
crystal and
magnetic structures, orthogonal transport channels for opposite
spins, and large band
spin splitting, which is a promising material for next-generation spintronics and magnonics. However, its
crystal and electronic structures remain inconclusive. Here, joint experimental and theoretical studies confirm and explain the appearance of its monoclinic structure and semiconducting band gap. We discover that an electronic instability appears in the tetragonal metallic state as the joint effect of density functional theory and Hubbard U correction (DFT+U) and results in a charge disproportionation, which in turn stabilizes the monoclinic distortion with narrow gap formation. The successful capture of this effect within DFT+U requires accounting for the relevant
symmetry-breaking energy-lowering channels – charge disproportionation and structural distortion; otherwise, tetragonal-
symmetry-constrained calculations yield only a metallic state. Fe$_2$PO$_5$ is thus best described as a correlation- and hybridization-assisted, distortion-coupled, charge-disproportionated
semiconductor. It represents a rare room-temperature semiconducting d-wave altermagnet. It also provides a rare platform for studying the coexistence of altermagnetism and charge density wave in quasi-one-dimensional systems.
Read the full abstract ▾
All authors Zhen Zhang, Mohd Anas, Andrey Kutepov, Parashu Kharel, Vladimir Antropov
Materials Science
Ultrafast nonlinear Hall effect in black phosphorus
Maciej Dendzik, Andrea Marini, Samuel Beaulieu et al. (+9 more)
The nonlinear
Hall effect (NHE) is a recently discovered member of the
Hall effect family in which the
Hall voltage shows a nonlinear behavior when a transverse electric field is applied. While the NHE does not require broken time-reversal
symmetry, such as that induced by a
magnetic field, it requires broken inversion
symmetry, which limits the range of suitable systems and potential applications. Here, we demonstrate an ultrafast NHE in centrosymmetric black phosphorus through dynamical
symmetry breaking using femtosecond light pulses. We provide a detailed microscopic picture of excited carrier dynamics and induced fields using momentum-resolved photoemission spectroscopy combined with ab-initio calculations. The ultrafast NHE is observed exclusively for the light polarization aligned with the armchair high-
symmetry direction and persists over 300 fs, which opens new possibilities for selective and ultrafast light-to-current conversions.
Read the full abstract ▾
All authors Maciej Dendzik, Andrea Marini, Samuel Beaulieu, Shuo Dong, Tommaso Pincelli, Julian Maklar, R. Patrick Xian, Enrico Perfetto, Martin Wolf, Gianluca Stefanucci, Ralph Ernstorfer, Laurenz Rettig
Materials Science
The HTC-Claw: Automating Discovery through High-Throughput Computational Campaigns
Lianduan Zeng, Xiao Zhou, Xueru Zheng et al. (+6 more)
With the advancement of the Materials Genome Initiative, high-throughput computation has become central to accelerating materials discovery. However, conventional first-principles workflows are cumbersome and error-prone. Existing high-throughput tools, while efficient at batch job submission, lack intelligence: they cannot automatically plan tasks based on scientific objectives or dynamically adapt workflows according to intermediate results. To address these limitations, this paper proposes and implements HTC-Claw, an intelligent high-throughput computational platform built upon the OpenClaw framework. The key innovations of HTC-Claw are: 1) An
agent-based framework for automatic decomposition of high-level research goals into parallelizable task sets; 2) A closed-loop execution engine that integrates real-time analysis and reporting; 3) Adaptive decision-making and workflow iteration capabilities based on intermediate results; and 4) A decoupled, modular architecture that separates the scheduling system from functional modules, enhancing extensibility and robustness. Case studies demonstrate that HTC-Claw enables an intelligent, end-to-end workflow from user intent to final reporting in materials exploration
Read the full abstract ▾
All authors Lianduan Zeng, Xiao Zhou, Xueru Zheng, Ning Gao, Lei Liu, Yunxuan Cao, Hongjian Chen, Zhongyang Wang, Tongxiang Fan
Mesoscale and Nanoscale Physics
Disentangling High Harmonic Generation from Surface and Bulk States of a Topological Insulator
Sha Li, Wenyi Zhou, Kazi A. Imroz et al. (+9 more)
The discovery of topological phases has introduced a new dimension to materials science. Three-dimensional (3D) topological
insulators (TIs) are a remarkable class of matter that is insulating in the bulk while hosting conductive topological surface states (TSSs) with unique charge and
spin properties. High-order harmonic generation (HHG) has emerged as a powerful tool to probe condensed matter systems by providing insights into their electronic structure and dynamic behavior. Here, we investigate HHG in the prototype 3D-TI Bi$_2$Se$_3$. We demonstrate that the contributions of bulk and surface states to the harmonic emission can be controlled by tuning the thickness of thin film samples. An ultrathin (6 nm) film substantially enhances HHG from the surface states, while the bulk states dominate HHG in a thicker (50 nm) film. By applying a quasi-static terahertz perturbing field, we disentangle the bulk and surface responses and reveal the significant impact of the surface states' shift vector and Berry
curvature on HHG. Our study provides effective methods for isolating the optical responses of TSSs from those of the bulk, which opens the door to resolving an ongoing debate regarding whether it is possible to reliably extract topological signatures in HHG.
Read the full abstract ▾
All authors Sha Li, Wenyi Zhou, Kazi A. Imroz, Yaguo Tang, Tiana A. Townsend, Vyacheslav Leshchenko, Larissa Boie, Pierre Agostini, Alexandra S. Landsman, Roland K. Kawakami, Lun Yue, Louis F. DiMauro
Materials Science
Large Language Model Assisted Discovery of Optimal Dopants for Enhanced Thermoelectric Performance in CoSb$_3$ Based Skutterudites
Yagnik Bandyopadhyay, Dylan Noel Serrao and Houlong L. Zhuang
We present a data-driven approach for accelerating the discovery of high-performance CoSb$_3$-based skutterudites by curating a comprehensive
dataset of compositions with various filler elements from over 300 research articles. Leveraging large
language models (LLMs), we extract and embed compositional representations, which are then used to train a regression head for predicting thermoelectric figure of merit. Compared to traditional deep neural networks relying on elemental descriptors such as atomic radii, our LLM-based model achieves significantly lower mean-squared error losses. We further employ the trained model to propose novel filler compositions with promising thermoelectric properties. Finally, we support these predicted candidates through density functional theory and molecular dynamics calculations to assess their electrical and thermal conductivity. This data-driven approach demonstrates the potential of combining natural
language processing, machine learning, and
quantum simulations for thermoelectric materials design.
Read the full abstract ▾
Materials Science · Cross-listed from physics.chem-ph
The BOS-Lig Dataset: Accurate Ligand Charges from a Consensus Approach for 66,810 Experimentally Synthesized Ligands
Roland G. St. Michel, Ryan J. Jang, Aaron G. Garrison et al. (+2 more)
Understanding ligand properties is essential for computational high-throughput screening of transition metal complexes. However, ligand properties such as net charge and other information such as their application area are often absent or inconsistently recorded in crystallographic
datasets. Here, we construct a ligand
dataset from 126,985 mononuclear transition metal complexes curated from the Cambridge Structural Database. Using an iterative charge-balancing workflow that combines complex charges, metal oxidation states, and consensus across crystallographic observations, we confidently assign net charges to 66,810 ligands among 94,581 identified unique ligand structures to curate the Boston Open-Shell Ligand (BOS-Lig)
dataset. The workflow assigns ligand charges in homoleptic complexes first and then iteratively propagates these assignments across heteroleptic environments, allowing charges to be inferred even when direct charge information is unavailable. We analyze cases where simple heuristics such as the octet rule would have failed and introduce a purity metric to identify when our charge assignments may be incorrect. Each ligand is also classified in terms of its metal coordinating atoms and whether there are multiple variants (i.e., hemilability). We then link complexes to their associated journal abstracts and apply a topic-modeling workflow to link 25,146 ligands with functional application areas spanning reactivity, redox chemistry, biological chemistry, and photophysical chemistry. Together, we provide an experimentally grounded
dataset of ligand chemical space that connects charge and functional application as a foundation for computational screening and data-driven ligand design.
Read the full abstract ▾
All authors Roland G. St. Michel, Ryan J. Jang, Aaron G. Garrison, Ilia Kevlishvili, Heather J. Kulik
Materials Science
RIXS Identification of Optical Phonon-Spin Coupling Effects in CrSBr
Jayajeewana N. Ranhili, Chamini S. Pathiraja, Brody Brogdon et al. (+10 more)
Resonant inelastic x-ray scattering provides experimental signatures of
spin-
phonon coupling in CrSBr through temperature-dependent Cr $L$-edge spectra. Low-energy excitations are observed exclusively in the low-temperature
antiferromagnetic phase as energy-loss features. A quasi-elastic peak at approximately 42 meV is observed under $\pi$-polarization. Density functional theory
phonon-mode calculations identify these RIXS features as occurring within the same energy range as bond-bending optical
phonon modes associated with distortions of the Cr–S–Cr network. The pronounced suppression of these low-energy excitations upon warming into the paramagnetic phase, together with their polarization dependence, the calculated
phonon spectrum, and a
spin-renormalized electron-
phonon RIXS framework, indicates a strong interplay between
magnetic correlations and
lattice dynamics. While the loss features appear at energies characteristic of optical
phonons, the significant overlap of the optical-
phonon and
magnon bands suggests that the temperature-dependent behavior should not be regarded as purely
lattice-derived excitations. Instead, the room-temperature suppression of the low-energy RIXS peaks is explained in terms of a
spin-
phonon coupling effect on the $L$-edge electron-
phonon RIXS mechanism. The interpretation is supported by the combined experimental observations,
phonon calculations, and theoretical modeling, rather than by temperature contrast alone. These results support
spin-
phonon coupling as a plausible and consistent interpretation of the observed temperature-dependent RIXS response and demonstrate that
magnetic order can strongly influence
phonon-related spectral weight in the RIXS spectrum.
Read the full abstract ▾
All authors Jayajeewana N. Ranhili, Chamini S. Pathiraja, Brody Brogdon, John Cenker, Xiaodong Xu, Daniel Chica, Xavier Roy, Stefano Agrestini, Mirian Garcia-Fernandez, Ke-Jin Zhou, Yi-De Chuang, Trinanjan Datta, Byron Freelon
Statistical Mechanics
Dynamical phase diagram of synchronization in one dimension: universal behavior from Edwards-Wilkinson to random deposition through Kardar-Parisi-Zhang
Ricardo Gutierrez and Rodolfo Cuerno
Synchronization in one dimension displays generic scale invariance with universal properties previously observed in surface kinetic roughening and the wider context of the Kardar-Parisi-Zhang (KPZ) universality class. This has been established for phase oscillators and also for some limit-cycle oscillators, both in the presence of columnar (quenched) disorder and of time-dependent noise, by extensive numerical simulations, and has been analytically motivated by continuum approximations in the strong oscillator coupling limit. The robustness and the precise boundaries in parameter space for such critical behavior remain unclear, however, which may preclude further developments, including the extension of these results to higher dimensions and the experimental observation of nonequilibrium criticality in synchronizing (e.g.~electronic or chemical) oscillators. We here present complete numerical phase diagrams of one-dimensional synchronization, including saturation times and values, but, most importantly, also dynamical features giving insight into the gradual emergence of synchronous dynamics, based on systems of phase oscillators with either type of randomness. In the absence of synchronization, the dynamics evolves as expected for random deposition (for time-dependent noise) or linear growth (for columnar disorder), while a crossover from Edwards-Wilkinson to Kardar-Parisi-Zhang behavior (with the corresponding type of randomness) is observed as the randomness strength, or the nonoddity of the coupling among oscillators, is increased in the synchronous region – their combined effect being partially captured by the so-called KPZ coupling. The distortion of scaling due to phase slips near the desynchronization boundary, a feature that is likely to play a role in experimental contexts, is also discussed.
Read the full abstract ▾
Statistical Mechanics
Comment on "Inferring the Dynamics of Underdamped Stochastic Systems"
Yeeren I. Low
D. B. Brückner et al. [Phys. Rev. Lett. 125, 058103 (2020)] have described a novel method for inferring the dynamics of systems governed by an underdamped Langevin equation in the presence of measurement noise. While this is a significant achievement, the paper also presents a number of significant errors. These are explained and corrected in this note.
Read the full abstract ▾
Statistical Mechanics · Cross-listed from quant-ph
Exploring bosonic bound states with parallel reaction coordinates
Guan-Yu Lai, Friedemann Queißer and Gernot Schaller
Bound states are dissipation-resilient states that may emerge when
quantum systems are strongly coupled to reservoirs with band gaps. We analyze an exactly solvable bosonic model for bound state existence and reproduce these results by a weak-coupling treatment of a supersystem composed of the original system and multiple reaction coordinates, which are individually representing small energy intervals of the reservoir spectral function. Within the perturbative supersystem treatment, the bound state stability results from its energy being inside the band gap. We discuss cases of multiple band gaps and also show that already in presence of weak interactions the bound state's lifetime is finite – but can be increased by raising the system-reservoir coupling strength.
Read the full abstract ▾
Statistical Mechanics · Cross-listed from math-ph
Analyticity, asymptotics and natural boundary for a one-point function of the finite-volume critical Ising chain
Yizhuang Liu
This note reports the following observation: the finite-volume expectation value of the
spin operator (the one-point function) between the $\mathbb{Z}_2$-even and odd ground states in the critical periodic Ising chain, when continued as a complex-analytic function of the system length $N$ through the Borel resummation of its large-$N$ expansion, has a natural boundary of analyticity along the negative real axis. The singular behavior near the negative real axis, after an exponential map, is the same as that of a Lambert-type series for the odd-divisor-squared sum near the unit circle $|z|=1$. The same divisor sum also governs the strengths of the Borel discontinuities of the one-point function's factorially-divergent large-$N$ asymptotics. We also report the all-order large-$N$ asymptotics of the leg function for the finite-volume
spin-operator form factor, and the similarities to certain known quantities in the literature.
Read the full abstract ▾
Quantum Gases
Rf spectra and pseudogap in ultracold Fermi gases across the BCS-BEC crossover from pairing fluctuation theory
Chuping Li, Lin Sun, Kaichao Zhang et al. (+5 more)
The pseudogap phenomenon is a hallmark of strongly interacting
Fermi systems, from high-temperature
superconductors to ultracold atomic gases, yet its precise origin remains debated. Here we calculate the spectral function and rf spectra of ultracold atomic gases across the BCS-BEC crossover to quantitatively investigate the pairing mechanism of the pseudogap. We advance our pairing fluctuation theory by incorporating particle-hole fluctuations, which renormalize the effective interaction in the particle-particle channel. To achieve quantitative accuracy, we employ a full numerical convolution for the pair susceptibility and self-energy, moving beyond previous analytic pseudogap approximations. This convolution approach automatically captures two critical effects: (i) the full spectral broadening of
fermions due to finite pair lifetime, and (ii) the previously neglected pair-hole scattering effect, which manifests as a substantial Hartree energy. We calculate the spectral function, and use rf spectral intensity maps and energy distribution curves to determine the quasiparticle dispersion. From these, we extract the pseudogap $\Delta$, Hartree energy, and chemical potential, mapping their
evolution across the crossover. Our results show that the pseudogap emerges continuously as the system moves from the BCS regime toward BEC. Furthermore, the pair spectral function reveals that pairs become diffusive at energies above 2$\Delta$, indicating that the pair lifetime is governed by virtual binding and unbinding processes. Our calculations achieve quantitative agreement with recent experiments across the BCS-BEC crossover, including at unitarity, providing strong support for a pairing-based origin of the pseudogap as described by our pairing fluctuation theory.
Read the full abstract ▾
All authors Chuping Li, Lin Sun, Kaichao Zhang, Junru Wu, Yuxuan Wu, Dingli Yuan, Pengyi Chen, Qijin Chen
Superconductivity
Numerically Exact Study of Flat-Band Superconductivity
I.S. Tupitsyn, B. Currie, B.V. Svistunov et al. (+2 more)
Current theories of high-temperature superconductivity in flat-band systems predict a linear dependence of the transition temperature on the attractive interaction, $T_c(U) = c|U|$. However, the value of $c$ and the full nonlinear $T_c(U)$ curve—with a maximum at large $|U|$—are known beyond mean-field and
quantum geometry estimates only for systems with isolated flat bands. Using a controlled diagrammatic Monte Carlo technique, we trace the onset of superfluid response in the Lieb
lattice with attractive Hubbard interaction. Focusing on the half-filled flat-band case, where the ordering mechanism differs fundamentally from both BCS and BEC (preformed Cooper pair) scenarios, we find that the pairing response diverges linearly with decreasing temperature over a broad range of $U$, leading to a sharp crossover to long-range correlations at a characteristic temperature $T_*$, which provides a controlled upper bound on $T_c$. The highest $T_*$ occurs when all three bands touch at a single momentum point, potentially corresponding to high $T_c$ values.
Read the full abstract ▾
All authors I.S. Tupitsyn, B. Currie, B.V. Svistunov, E. Kozik, N.V. Prokof'ev
Superconductivity
Band-basis decomposition of superfluid weight in magic-angle twisted bilayer graphene: Quantifying geometric and conventional contributions
Jian Zhou
We decompose the superfluid weight D_s of magic-angle twisted
bilayer graphene (MATBG) into conventional (band-velocity) and
geometric (interband-coherence) contributions using a band-basis current operator splitting applied to the Bistritzer-MacDonald continuum model. In the flat-band subspace,
quantum geometry accounts for 22-26% of D_s at charge neutrality depending on pairing
symmetry, with cross terms vanishing to machine precision. Including remote bands raises the
geometric fraction to ~55-58%, while D_s^conv converges to within 2% – demonstrating that remote bands contribute exclusively through interband coherence. The
geometric fraction peaks at ~27-33% near the nu = +/- 2 fillings where superconductivity is strongest, and is insensitive to gap magnitude in the experimentally relevant range.
Read the full abstract ▾
Statistical Mechanics · Cross-listed from hep-th
Background Fields Meet the Heat Kernel: Gauge Invariance and RGEs without diagrams
Debanjan Balui, Joydeep Chakrabortty, Christoph Englert et al. (+2 more)
We introduce a new method that exploits the combination of the Heat Kernel (HK) and Background Field Method to compute gauge-invariant and gauge parameter-independent quantities such as the effective potential, anomalous dimensions, and renormalization group equations. In contrast to currently employed techniques, these results are obtained exclusively from the dynamics of the background fields, without relying on supplementary input from, e.g., traditional diagrammatic calculations. This is achieved by a consistent treatment of open and closed derivatives in the HK expansions. In this way, we compute the standard quantities such as $\beta$ functions and their gauge-parameter independence when background fields are on-shell. We demonstrate this formalism for instructive examples such as Scalar QED and Yukawa theory. Full results for the bosonic part of the Standard Model provide further validation of our approach.
Read the full abstract ▾
All authors Debanjan Balui, Joydeep Chakrabortty, Christoph Englert, Subhendra Mohanty, Tushar
Materials Science
Composition design of refractory compositionally complex alloys using machine learning models
Tao Liang, Eric A. Lass, Haochen Zhu et al. (+5 more)
Refractory compositionally complex
alloys (RCCAs) are considered the next generation high-temperature materials. However, their high-dimensional composition spaces are too large to explore by traditional density functional theory or experimental means, making new RCCA discovery slow and cumbersome. This work has addressed these challenges with an integrated composition design framework that can efficiently and exhaustively explore the relationship between the compositions and two fundamental aspects: 1) the phase stability, including the target body-centered cubic (BCC) phase and its competing phases (hexagonal closed-pack (HCP) structures, Laves and B2 intermetallic phases), and 2) the mechanical properties. This framework is demonstrated with RCCAs within nine refractory metals (Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W). Theory-guided machine learning (ML) models were employed to find the composition-mechanical property relationship of RCCAs, where the established theory is used to supplement the yield strength data at ultra-high temperature, and a forward sequential feature selection (SFS) is used to determine feature selection. The resulting ML model for temperature-dependent yield strength was found to have an R_squared value of 0.98 over the entire temperature range (from 0 to 2000 K). The impact of each constituent element on the six key properties is evaluated. The addition of Nb tends to stabilize the BCC phase and the addition of Ti improves the ductility of RCCAs. Combined with all methods involved in this framework, the on-demand designer allows the
alloy designers to have all properties for any RCCA compositions and narrow down the composition space by applying custom screening criteria. The output from the predictor and screener provides valuable guidance for our experimental study of RCCAs and accelerates the pace of materials discovery.
Read the full abstract ▾
All authors Tao Liang, Eric A. Lass, Haochen Zhu, Carla Joyce C. Nocheseda, Philip D. Rack, Stephen Puplampu, Dayakar Penumadu, Haixuan Xu
Materials Science
Lattice location of ion-implanted 6He in diamond
U. Wahl, J.G. Correia, A. Costa et al. (+7 more)
The properties of He in diamond are of interest with respect to geological dating and the creation of color centers with possible
quantum applications. We report on the
lattice location of the short-lived ion implanted
nuclear probe 6He (t1/2=807 ms) in diamond, which was performed using the beta emission channeling method at CERN's ISOLDE facility. 6He was implanted with 30 keV into a single-crystalline artificial diamond sample kept at a temperature ranging from 30 deg C up to 800 deg C. By means of comparing the measured emission channeling patterns along different crystallographic directions with simulated yields for a variety of possible sites, we conclude that the implanted 6He occupies tetrahedral (T) interstitial sites, in agreement with theoretical predictions that T sites should be the preferred position of He in diamond. Implantation at 800 deg C resulted in a drop in the tetrahedral interstitial fraction by 20%, which we interpret as the onset of
diffusion, 6He thus being able to change to
lattice sites of low crystallographic
symmetry, or reach the surface of the sample or escape to the bulk during its lifetime. We estimate the activation energy for interstitial migration of He to be around 1.63-2.89 eV, which agrees with theoretical predictions of 1.41-2.36 eV from the literature. Activation energies around 2 eV would mean that simple interstitial He cannot be stable in diamond on geological time scales, thus to remain inside, it should be bound to some defect in the material or exist in another form such as within inclusions of other minerals or
liquids, or possibly small He bubbles.
Read the full abstract ▾
All authors U. Wahl, J.G. Correia, A. Costa, B. Biesmans, G. Magchiels, S.M. Tunhuma, A. Lamelas, A. Vantomme, L.M.C. Pereira, the ISOLDE Collaboration