Materials Science
A large-scale nanocrystal database with aligned synthesis and properties enabling generative inverse design
Kai Gu, Yingping Liang, Senliang Peng et al. (+3 more)
The synthesis of nanocrystals has been highly dependent on trial-and-error, due to the complex correlation between synthesis parameters and physicochemical properties. Although deep learning offers a potential methodology to achieve generative inverse design, it is still hindered by the scarcity of high-quality
datasets that align nanocrystal synthesis routes with their properties. Here, we present the construction of a large-scale, aligned Nanocrystal Synthesis-Property (NSP) database and demonstrate its capability for generative inverse design. To extract structured synthesis routes and their corresponding product properties from literature, we develop NanoExtractor, a large
language model (LLM) enhanced by well-designed augmentation strategies. NanoExtractor is validated against human experts, achieving a weighted average score of 88% on the test set, significantly outperforming chemistry-specialized (3%) and general-purpose LLMs (38%). The resulting NSP database contains nearly 160,000 aligned entries and serves as training data for our NanoDesigner, an LLM for inverse synthesis design. The generative capability of NanoDesigner is validated through the successful design of viable synthesis routes for both well-established PbSe nanocrystals and rarely reported MgF2 nanocrystals. Notably, the model recommends a counter-intuitive, non-stoichiometric precursor ratio (1:1) for MgF2 nanocrystals, which is experimentally confirmed as critical for suppressing byproducts. Our work bridges the gap between unstructured literature and data-driven synthesis, and also establishes a powerful human-AI collaborative paradigm for accelerating nanocrystal discovery.
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All authors Kai Gu, Yingping Liang, Senliang Peng, Aotian Guo, Haizheng Zhong, Ying Fu
Strongly Correlated Electrons
Pseudospin Formulation of Quench Dynamics in the Semiclassical Holstein Model
Lingyu Yang, Ho Jang, Sankha Subhra Bakshi et al. (+2 more)
We present a pseudospin formulation for the post-quench dynamics of charge-density-wave (CDW) order in the half-filled spinless Holstein model on a square
lattice, assuming spatially homogeneous
evolution. This Anderson pseudospin description captures the coherent nonequilibrium dynamics of the coupled electron-
lattice system. Numerical simulations reveal three distinct dynamical regimes of the CDW order parameter following a quench-locked oscillations, Landau-damped dynamics, and overdamped relaxation-closely paralleling quench dynamics in BCS
superconductors and other electronically driven
symmetry-breaking phases. Crucially, however, the presence of dynamical
lattice degrees of freedom leads to qualitatively different long-time behavior. In particular, while the oscillation amplitude is reduced in the damped regimes, CDW oscillations do not fully decay but instead persist indefinitely due to feedback from the
lattice field. We further show that these persistent oscillations are characterized by a nonequilibrium electronic distribution, which provides an intuitive understanding of both their amplitude and the renormalization of the oscillation frequency relative to the bare Holstein
phonon frequency. Our results highlight the essential role of
lattice dynamics in nonequilibrium ordered phases and establish a clear distinction between electron-
lattice-driven CDW dynamics and their purely electronic counterparts.
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All authors Lingyu Yang, Ho Jang, Sankha Subhra Bakshi, Yang Yang, Gia-Wei Chern
Soft Condensed Matter · Cross-listed from physics.plasm-ph
Excess energy of strongly coupled one-component plasma from variational approach
S. A. Khrapak and A. G. Khrapak
The excess energy of the one-component
plasma fluid is calculated using the variational approach combined with different variants of the excess
entropy of the hard-sphere fluid, which is used as a reference system. Our comparison with recent Monte Carlo results for the excess energy of the one-component
plasma identifies the Percus-Yevick virial
entropy as the most accurate
entropy to be used in the variational calculation of this kind. The reason for this and potential developments of the present analysis are briefly discussed. We demonstrate that the original Rosenfeld-Tarazons scaling of the thermal component of the excess energy of the one-component
plasma fluid is in excellent agreement with recent Monte Carlo results.
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Mesoscale and Nanoscale Physics
Probing the dynamics and configurations of single molecule junctions via Seebeck coefficient spectroscopy
Juan Hurtado-Gallego, Jeremie Pirard, Abdalghani H. S. Daaoub et al. (+5 more)
Single molecule junctions exhibit dynamic structural configurations that strongly influence their electronic and thermoelectric properties. Here, we combine conductance (G) and Seebeck coefficient (S) measurements using the novel AC based scanning tunnelling microscope break junction technique to probe the real-time
evolution of oligo(phenylene ethynylene) molecular junctions. We show that most junctions undergo configuration changes that lead to notable changes in S while G remains nearly constant. Density functional theory and
quantum transport simulations link these observations to variations in contact geometry and charge transfer at the molecule electrode interface. Our results demonstrate that simultaneous G and S measurements enable direct access to the dynamic reconfiguration of single molecule junctions and offer design insights for thermoelectric molecular devices and new routes for increasing single molecule junction stability.
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All authors Juan Hurtado-Gallego, Jeremie Pirard, Abdalghani H. S. Daaoub, Sara Sangtarash, Charlotte Kress, Marcel Mayor, Hatef Sadeghi, Pascal Gehring
Statistical Mechanics
Variation on the theme of Jarzynski's inequality
Dani R. Castellanos and Petr Jizba
The Jarzynski equality, which relates
equilibrium free-energy difference to an average of non-
equilibrium work, plays a central role in modern non-
equilibrium statistical thermodynamics. In this paper, we study a weaker consequence of this relation, known as Jarzynski's inequality, which can be formally obtained from the Jarzynski equality via Jensen's inequality. We identify and analyze several extensions of Jarzynski's inequality that go beyond its direct derivation from the Jarzynski equality. In particular, we consider chemical systems both in the linear-response regime and away from linear thermodynamics. Furthermore, by employing functional-integral techniques, we extend Jarzynski's inequality to many-body statistical systems described by
quantum field theory. Salient issues, such as connections of the Jarzynski inequality with the maximum work
theorem and the Landau–Lifshitz theory of fluctuations, are also discussed.
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Superconductivity
Orbital Separation of Charge Order and Superconductivity in La$_{2-x}$Sr$_{x}$CuO$_4$
I. Biało, O. Gerguri, L. Martinelli et al. (+12 more)
We report a combined x-ray absorption (XAS) and oxygen $K$-edge resonant inelastic x-ray scattering (RIXS) study of charge order in underdoped La$_{2-x}$Sr$_x$CuO$_4$ ($x=0.125$) under uniaxial $c$-axis pressure. We find that compressive $c$-axis strain modifies the charge order only within the superconducting state, with a striking polarization dependence: suppression in the $d_{x^2-y^2}$ channel and enhancement in the $d_{z^2}$ channel. X-ray absorption spectra reveal concomitant strain-induced modifications of the oxygen pre-edge and upper Hubbard band, consistent with increased $d_{z^2}$ orbital admixture. Our results suggest that $c$-axis pressure drives an orbital separation between superconductivity, rooted in $d_{x^2-y^2}$ states, and charge order, which gradually shifts to the $d_{z^2}$ channel. This orbital separation reveals a way for superconductivity and charge order to coexist in the cuprates with minimal competition. Furthermore, it suggests that the multi-order phase diagram of La$_{2-x}$Sr$_{x}$CuO$_4$ cannot be realistically described within single band models usually used to describe cuprate physics.
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All authors I. Biało, O. Gerguri, L. Martinelli, J. Küspert, J. Choi, M. Garcia-Fernandez, S. Agrestini, K. J. Zhou, E. Weschke, T. Kurosawa, N. Momono, M. Oda, C. Lin, Q. Wang, J. Chang
Superconductivity
Fast and Slow Sound Excitations in Nematic Aerogel in superfluid 3He
A.M. Bratkovsky
Nematic aerogel (nAG) supports so-called polar phase in
liquid 3He. The experiment [Dmitriev et al, JETP Lett. 112, 780 (2020)] showed that the onset of polar phase inside the nAG is accompanied by emergence of a sound wave with frequency quickly growing with cooling down from transition temperature and reaching a plateau. To describe this behavior, we start by calculating the elastic properties of the dry nematic AG that appear to depend only on Young's modulus of the parent material (e.g. mullite), the volume fraction of the solid phase and the aspect ratio of the representative volume of nAG. The elastic constants are then used to solve elasto-hydrodynamic equations for various sound vibrations of nAG filled with 3He. The (isotropic) first sound and anisotropic second sound in the polar phase are strongly hybridized with fourth sound and standard elastic modes in nAG. The hybrid second and the transverse fourth sound start with zero velocity at the transition, similar to pure 3He, and quickly grow with lowering temperature until they hit the sample finite size cutoff.
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Quantum Gases · Cross-listed from quant-ph
Quantum simulation with Rydberg ions in a Penning trap
Wilson S. Martins, Markus Hennrich, Ferdinand Schmidt-Kaler et al. (+1 more)
Quantum simulation of interacting many-body
spin systems is routinely performed with cold trapped ions, and systems with hundreds of
spins have been studied in one and two dimensions. In the most common realizations of these platforms,
spin degrees of freedom are encoded in low-lying electronic levels, and interactions among the
spins are mediated through
crystal vibrations. Here we propose a new approach which enables the
quantum simulation of two-dimensional
spin systems with interaction strengths that are increased by orders of magnitude. This, together with the unprecedented longevity of trapped ions, opens an avenue for the exploration of phenomena that take place on long timescales, e.g., slow and collective relaxation in frustrated and kinetically constrained systems. Our platform makes use of the strong dipolar interactions among electronic Rydberg states and planar confinement provided by a Penning trap. We investigate how the strong electric and
magnetic fields that form this trap affect the properties of the Rydberg states and show that
spin-
spin interaction strengths on the order of MHz are achievable under experimentally realistic conditions. As a brief illustration of the capabilities of this
quantum simulator, we study the
entanglement in a frustrated
spin system realized by three ions.
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All authors Wilson S. Martins, Markus Hennrich, Ferdinand Schmidt-Kaler, Igor Lesanovsky
Materials Science
Magnetic Structures Database from Symmetry-aided High-Throughput Calculations
Hanjing Zhou, Yuxuan Mu, Dingwen Zhang et al. (+11 more)
Magnetic structures-the spatial arrangement of
magnetic moments-underpin the diverse functionalities of
magnetic materials, yet they have been experimentally determined for only a small fraction of known compounds. Conventional first-principles prediction requires candidate
magnetic configurations as input, but the number of possible configurations is in principle infinite. Although the classic Landau-theory based
symmetry analysis is widely used to classify
magnetic ordering, their direct application to generate input
magnetic configurations remains a major challenge due to unavoidable residual degrees of freedom. Here we turn this classification
language into a practical predictive framework by resolving these freedoms through a two-step
symmetry-aided strategy: an irrep-compatible maximal-
magnetic-subgroup selection, followed by the physically motivated high-
symmetry-direction construction. This highly efficient scheme is justified within the newly developed oriented
spin space group framework. Benchmarked against 1,043 Landau-compatible experimental structures in MAGNDATA, our candidate sets reproduce 90% of the experimentally reported
magnetic structures in the four high-
symmetry crystal systems with only ~51 candidates per material on average, and subsequent first-principles calculations with material-specific Hubbard U parameters recover the experimental ground state with 83% accuracy. Applying the validated workflow to 19,808 transition-metal compounds, we construct a database of more than 5,000
magnetic materials-nearly twice the size of the experimental MAGNDATA. The database reveals statistical regularities accessible only at scale, including the occurrence rate of magnetism, the prevalence of competing
magnetic states, and enables the identification of hundreds of
magnetic topological materials, altermagnets, and other emerging
magnetic phases and functionalities.
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All authors Hanjing Zhou, Yuxuan Mu, Dingwen Zhang, Yuhui Li, Xiaobing Chen, Hangbing Chu, Fan Jiang, Erjun Kan, Chun-Gang Duan, Di Wang, Huimei Liu, Qihang Liu, Xin-Gao Gong, Xiangang Wan
Strongly Correlated Electrons
Atomic structure and formation mechanism of a newly discovered charge density wave in the m=2 monophosphate tungsten bronze
Arianna Minelli, Elen Duverger-Nedellec, Olivier Perez et al. (+6 more)
The $m$=2 member of the monophosphate tungsten bronze family has been considered the only one in the family without an electronic instability at low temperature. In this paper, we report the discovery of a charge density wave phase in this compound, with a transition temperature of 290 K and an incommensurate modulation vector q=0.245b*+ $\upxi$c*. The presence of this new phase is confirmed by diffraction and resistivity measurements. Pre-transitional dynamics are investigated using diffuse and inelastic x-ray scattering, revealing a clear Kohn anomaly. We analyze both structural and electronic contributions to the phase transition, providing a comprehensive picture of the mechanism driving this newly identified instability.
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All authors Arianna Minelli, Elen Duverger-Nedellec, Olivier Perez, Alain Pautrat, Adrien Girard, Johnathan Bulled, Marek Mihalkovič, Marc de Boissieu, Alexei Bosak
Statistical Mechanics
Renewal theory for Brownian motion with stochastically gated targets
Paul C Bressloff
There are a wide range of first passage time (FPT) problems in the physical and life sciences that can be modelled in terms of a Brownian particle binding to a reactive surface (absorption). However, prior to absorption, the particle may undergo several rounds of surface attachment (adsorption), detachment (desorption) and
diffusion. Alternatively, the surface may be stochastically gated so that absorption can only occur when the gate is open. In both cases one can view each return to the surface as a renewal event. In this paper we develop a renewal theory for stochastically gated FPT problems along analogous lines to previous work on adsorption/desorption processes. We proceed by constructing a renewal equation that relates the joint probability density for particle position and the state of a gate (or multiple gates) to the probability density and FPT density for a totally absorbing (non-gated) boundary. This essentially decomposes sample paths into an alternating sequence of bulk
diffusion and instantaneous adsorption/desorption events, which is terminated when adsorption coincides with an open gate. Through a variety of examples, we show how renewal theory provides a general mathematical framework for incorporating
stochastic gating into FPT problems.
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Soft Condensed Matter
Non-reciprocal visual perception and polar alignment drive collective states in chiral active particles
Diganta Bhaskar, Abhishek Chaudhuri and Anil Kumar Dasanna
Self-propelled particles rarely move in straight lines; environmental interactions, shape asymmetry, and intrinsic torques generically induce curved or fluctuating trajectories. In biological and synthetic systems, this
curvature often coexists with directional sensing and non-reciprocal interactions. Motivated by this, we explore the collective dynamics of
chiral intelligent active Brownian particles (iABPs) that combine polar
alignment with
vision-based sensing. By varying the ratio of
alignment to visual maneuverability, the
vision angle, and the reduced chirality $(\omega/D_r)$, we construct a phase diagram exhibiting diverse collective states: spinners,
vortices, ripples, worm-like swarms, rotary clusters, and irregular aggregates. Chirality critically governs their morphology: high chirality yields dilute phases, while moderate to low chirality produces cohesive yet dynamic patterns. Ripple loops emerge as a distinct state, characterized by expanding ring-like motion driven by outward torques and sustained only when both particle number and visual maneuverability are large. Structural and dynamical measures, including polarization, pair correlations, mean-square displacement, and orientation correlations, reveal clear signatures distinguishing these phases. Overall, our results show how chirality, non-reciprocal perception, and
alignment together generate collective states inaccessible to non-
chiral systems, with implications for
chiral active matter in biological and synthetic contexts.
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Mesoscale and Nanoscale Physics
Manipulating Anomalous Transport via Crystal Symmetry in 2D Altermagnets
Dan Li, Shuaiyu Wang, Jiabin chen et al. (+7 more)
Anomalous transports, including the anomalous
Hall effect (AHE) and anomalous Nernst effect (ANE), are typical manifestations of time-reversal-
symmetry-breaking responses in materials. In general, the two
Hall states with opposite
Hall conductivities can be regarded as time-reversal pairs coupled to
magnetic order, and switching between them relies on reversing the magnetization via an external
magnetic field or electric current. Here, we introduce a approach for manipulating anomalous transport through
crystal symmetry engineering in two-dimensional (2D) altermagnetic systems. Based on
symmetry analysis, we demonstrate that 2D altermagnets (AM) with out-of-plane Néel vectors will not host any anomalous
Hall transport. Remarkably, breaking the
symmetry connecting the two
magnetic sublattices, an anomalous
Hall response can emerge immediately, and the signs of the anomalous
Hall and anomalous Nernst conductivities can be flexibly controlled by the
symmetry-breaking term, thereby realizing tunable sign-reversible anomalous transport. Furthermore, the feasibility of the theoretical scheme is further verified by explicit
lattice-model construction. Using first-principles calculations, we investigate the realization of
crystal symmetry-controlled anomalous transport in a 2D AM material Cr$_{2}$O$_{2}$. The results indicate that Cr$_{2}$O$_{2}$ with out-of-plane Néel vectors can sequentially exhibit the AHE and
quantum anomalous
Hall effect (QAHE) under continuous uniaxial strain. Interestingly, the sign reversal between these two effects can be achieved by simply rotating the strain direction by C$_{4z}$
symmetry. The corresponding ANE and its sign reversal are also revealed. Our findings provide a new strategy to manipulate anomalous transport, and should have significant potential applications.
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All authors Dan Li, Shuaiyu Wang, Jiabin chen, Zeling Li, Chaoxi Cui, Lei Li, Lei Wang, Zhi-Ming Yu, Xiaodong Zhou, Xiao-Ping Li
Statistical Mechanics · Cross-listed from quant-ph
Utilizing intermediate states in quantum annealing for multi-objective optimization
Keita Takahashi and Shu Tanaka
We investigate obtaining intermediate
quantum states during the
quantum annealing process to address the limitation of the linear weighted sum method in multi-objective optimization, which inherently fails to reach non-convex regions of the Pareto front. We validate this approach through physical experiments utilizing quench-based readout and numerical simulations assuming ideal mid-anneal measurements. Both methods consistently demonstrate a clear trade-off where earlier timing enhances diversity of the solutions, whereas later timing ensures convergence to non-dominated solutions. Notably, a practical compromise timing balances both metrics. The qualitative agreement between practical quench and ideal simulation indicates the potential of accessing the intermediate states for comprehensive Pareto front exploration.
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Mesoscale and Nanoscale Physics
The transmembrane potential across a charged nanochannel subjected to asymmetric electrolytes
Ramadan Abu-Rjal and Yoav Green
The transmembrane voltage, $V$, which is the potential drop required to nullify the electrical current ($i=0$), is a key characteristic of water desalination and energy harvesting systems that utilize macroscopically large nanoporous membranes, as well as for physiological ion channels subjected to asymmetric salt concentrations. To date, existing analytical expressions for $V_{i=0}$ have been limited to simple scenarios or under simplifying assumptions. In this work, we derive two expressions for $V_{i=0}$. First, we consider the much simpler scenario of two species. Then, we can consider an electrolyte comprised of an arbitrary number of species. The difference in the models is that the latter solution utilizes an ad-hoc assumption of a linear concentration profile, while the former solution does not require such an ad-hoc assumption. We analyze both models and show how to reduce them to several known models. We also verify both models with numerical simulations of the one-dimensional Poisson-Nernst-Planck equations. We show how the interplay between
diffusion coefficients and ionic valencies significantly varies the system response and why it is essential to account for all system parameters. Ultimately, this model can be used to improve experimental interpretation of ion transport measurements
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Strongly Correlated Electrons
Imaging Intermediate Melting Phases of Dual Magnetic-Field-Stabilized Wigner Crystals
Chaofei Liu, Jianwang Zhou, Wenao Liao et al. (+7 more)
The competition between Coulomb repulsion and kinetic energy in correlated systems can allow electrons to crystallize into Wigner solids. Despite researches across diverse two-dimensional Wigner platforms, the microscopic melting processes through possible intermediate phases remains largely unknown. Here, we present the visualization of electron-
lattice melting in monolayer VCl3 on graphite, where two Wigner
crystals coexist with markedly different critical temperatures Tc and
lattice periods as stabilized by high
magnetic field. One Wigner
crystal possesses both record-high Tc and electron density, and undergoes melting through an intermediate nematic phase upon decreasing
magnetic field. In contrast, the other Wigner
crystal with a lower Tc yields a different intermediate phase during melting, exhibiting an anomalous electron
liquid with an energy-independent modulation period. First-principles calculations corroborate the band-selective occupations of interface-transferred electrons in the formation of dual Wigner
crystals. Our atomically resolved intermediate phases provide crucial insights into the microscopic melting pathways of Wigner
crystals, enabling a phase diagram parameterized by both
quantum and thermal fluctuations.
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All authors Chaofei Liu, Jianwang Zhou, Wenao Liao, Zeyu Jiang, Chao Zhang, Tingfei Guo, Tianyou Zhai, Wenhao Zhang, Ying-Shuang Fu, Qi-Kun Xue
Mesoscale and Nanoscale Physics
Band-Edge Carrier Trapping Limits Light Emission in WSe$_2$
Juri G. Crimmann, Sander J. W. Vonk, Yannik M. Glauser et al. (+2 more)
Monolayers of transition metal dichalcogenides (TMDs) exhibit bright photoluminescence, a desirable property for light-emitting diodes and single-
photon emitters. Because the emission intensity is heavily influenced by factors such as defect density and oxidation, it is critical to understand how they affect photoluminescence efficiency. However, due to the time-consuming process of identifying individual monolayers, studies of high-quality exfoliated TMDs have been limited to only a few samples. Here, we present an investigation of excited-state lifetimes and spectra for over 200 WSe$_2$ exfoliated monolayers at room temperature. We find a linear correlation between photoluminescence lifetime and intensity across hundreds of monolayers and within individual monolayers. Results from intentional photooxidation experiments indicate that this correlation is due to photoinduced band-edge carrier traps, which introduce a nonradiative decay pathway that competes with
exciton emission. Our work highlights the importance of controlling such traps, as they are the primary limitation of bright photoluminescence.
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All authors Juri G. Crimmann, Sander J. W. Vonk, Yannik M. Glauser, Gabriel Nagamine, David J. Norris
Strongly Correlated Electrons
Non-invertible symmetries and mixed anomalies from equations of motion in (3+1)D twisted $BF$ topological quantum field theories
Zhi-Feng Zhang, Yizhou Huang, Qing-Rui Wang et al. (+1 more)
We develop a systematic study on the topological operators that generate invertible and non-invertible higher-form
symmetries in $\left(3+1\right)D$ twisted $BF$ topological
quantum field theories (TQFTs). We focus on the twisted $BF$ theories with gauge group $G=\prod_i \mathbb{Z}_{N_i}$ and an $a\wedge a\wedge b$ twist, where $a$'s and $b$ are 1-form and 2-form gauge fields, respectively. These theories realize non-Abelian $(3+1)$D TQFTs supporting Borromean-Rings braiding and describe three-dimensional non-Abelian topological orders in condensed matter. For $G=(\mathbb{Z}_2)^3$, a microscopic realization is given by the $\mathbb{D}_4$ Kitaev
quantum double model. Starting from the equations of motion (EoMs), we construct gauge invariant operators that are supported on closed submanifolds, hence are genuine topological operators. Some of them are associated with nontrivial
Hilbert spaces which are the projective representation spaces of specific gauge subgroups, thus being non-invertible. The others are invertible topological operators with group-like fusion rules. The fusion rules of non-invertible topological operators correspond to the decomposition of the product of the projective representation spaces. We provide a field-theoretical
algorithm to calculate the fusion rules. Besides, we identify an obstruction to retaining a non-invertible topological operator after gauging an invertible
symmetry, and derive the constraints on pairs of non-invertible operators relevant to simultaneous gauging. Our results give a unified and practical approach for identifying and characterizing higher-form
symmetries and mixed anomalies, which can be extended to more general TQFTs and topological orders.
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All authors Zhi-Feng Zhang, Yizhou Huang, Qing-Rui Wang, Peng Ye
Materials Science
Electrical Regulation of Transverse Spin Currents in Unconventional Magnetic Ferroeletrics
Yudi Yang, Zhuang Qian, Ruichun Xiao et al. (+4 more)
We identify hexagonal YMnO$_3$ as a material realization of the elusive $\beta$-phase of unconventional magnetism, a noncollinear, noncoplanar
antiferromagnetic state defined by intrinsic
spin-momentum locking and a topological
spin texture. First-principle calculations reveal that this unique electronic structure enables a perpendicular electric field to generate a transverse pure
spin current, a response that occurs without requiring relativistic
spin-orbit coupling.
Symmetry analysis demonstrates that this
spin current is intimately related to the material's ferroelectric polarization that breaks the inversion
symmetry and is rigorously forbidden at domain walls where electrical polarization vanishes. This provides a blueprint for a non-volatile transistor where a gate voltage switches the
spin current conductivity by controlling domain wall density, enabling all-electrical control for energy-efficient
antiferromagnetic spintronics.
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All authors Yudi Yang, Zhuang Qian, Ruichun Xiao, Yuanyuan Xu, Hua Wang, Shi Liu, Congjun Wu
Materials Science
Sol-Gel-Derived NiO/ZnO Thin Films with Single and Heterostructure Layers for Electrochemical Energy Storage
Miss Nourin Nurain Amina, Md Noushad Hossain, Muhammad Shahriar Bashar et al. (+2 more)
NiO/ZnO-based thin films, including single-layer and
heterostructure configurations, were synthesized to investigate the influence of stacking order on their electrochemical performance for supercapacitor applications. To improve the relatively low capacitive performance of ZnO compared to NiO, NaCl was introduced as a dopant. All films were deposited using a non-
vacuum spin-coating method on fluorine-doped tin
oxide (FTO) substrates, chosen for their excellent electrical conductivity and stability as electrode materials. The surface morphology and structural parameters were examined using scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. Optical properties were analyzed via UV-Vis spectroscopy, revealing direct band gaps in the range of 3.17-3.31 eV for ZnO and Na-ZnO, and wider gaps up to 3.81 eV for NiO. Electrochemical performance was evaluated using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) in a three-electrode configuration with 1 M KOH as the electrolyte. Among the electrodes, the single-layer NiO film exhibited the highest specific capacitance of 1.391 Fg^{-1}. In contrast, the NiO/ZnO
heterostructure demonstrated a synergistic effect, resulting in enhanced charge storage and achieving a maximum specific capacitance of 1.627 Fg^{-1} at a current density of 2.0 mA cm^{-2}. Furthermore, sodium doping significantly improved the capacitance of ZnO. Overall, the results highlight the potential of sol-gel-derived
oxide heterostructures and doped thin films as cost-effective and scalable electrode materials for supercapacitors in portable electronics and energy storage systems.
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All authors Miss Nourin Nurain Amina, Md Noushad Hossain, Muhammad Shahriar Bashar, Munira Sultana, Md. Salahuddin Mina
Soft Condensed Matter
Association and phase transitions in simple models for biological and soft matter condensates
Cecilia Bores, Antonio Diaz-Pozuelo and Enrique Lomba
We investigate a set of design principles that link specific features of interparticle interactions to predictable structural and dynamic outcomes in two-dimensional self-assembly, a framework relevant to soft matter and biological condensates. Using extensive Molecular Dynamics simulations of single- and two-component systems, we systematically dissect how modifications to competing short-range attraction and long-range repulsion (SALR) potentials (both isotropic and anisotropic) serve as independent control parameters. In particular, we have focused on tuning the repulsive barrier height, decorating the attractive well with oscillatory components, and changing particle geometry. We demonstrate that these modifications dictate cluster size distributions, the degree of intra-cluster ordering, the geometry of the clusters, and the propensity for inter-cluster crystallization. A key finding is the decoupling of internal and global dynamics: oscillatory wells promote solid-like order within clusters while maintaining
liquid-like cluster mobility. Furthermore, we show how asymmetric interactions in a binary SALR mixture can be designed to induce internal phase segregation within condensates. Complementing this, we observe that in anisotropic models in which the short rage component of the interaction stems from the presence of attractive patchy sites, stoichiometry and the
geometric distribution of the patches are essential to control self-assembly and cluster morphology, whereas long-range repulsion can be used to tune cluster size and polydispersity. The extracted principles provide a causal road-map for engineering self-assembled materials and a set of basic physical concepts for interpreting the complex phase behavior of biomolecular condensates.
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Materials Science
Spontaneous growth of perfectly circular domains of MoS2 monolayers using chemical vapour deposition technique
Umakanta Patra and Subhabrata Dhar
Very large-scale integration of devices in a circular pattern has several advantages over the commonly used rectangular grid layout. For the development of such integrated
circuits on a 2D
semiconductor platform, spontaneous growth of the material in the form of circular islands is desirable. Here, we report the natural formation of 1L-MoS2 circular islands of diameter as large as a few hundreds of micrometer on SiO2/Si substrates by chemical vapor deposition (CVD) technique without the use of any seeding layer. The size of the circles is found to increase with the amount of sulphur used during growth. The study reveals that these circular islands are formed with a less-defective interior and a more-defective outer part that is dominated by a large density of grain boundaries and twists. Due to the lower defect density, the interior region yields much higher photoluminescence than the peripheral part. Field effect transistors (FETs) are fabricated on inner and outer portions of a circle to estimate the mobility and concentration of the background carriers in the two regions. The study shows that the maximum mobility is more than double in the interior than the outer part. While the carrier concentration remains practically unchanged in the two regions. The natural tendency to minimize the strain energy resulting from the mismatch between the thermal expansion coefficients of the monolayer and the substrate as well as the edge energy that originates from the boundary tension are thought to be the driving forces behind the formation of these circular domains.
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Mesoscale and Nanoscale Physics
Generating unconventional spin-orbit torques with patterned phase gradients in tungsten thin films
Lauren J. Riddiford, Anne Flechsig, Shilei Ding et al. (+7 more)
A key aim in spintronics is to achieve current-induced magnetization switching via
spin-orbit torques without external
magnetic fields. For this, the focus of recent work has been on introducing controlled lateral gradients across ferromagnet/heavy-metal devices, giving variations in thickness, composition, or interface quality. However, the small gradients achievable with common growth techniques limit both the impact of this approach and understanding of the underlying physical mechanisms. Here,
spin-orbit torques are patterned on a mesoscopic length scale in tungsten thin films using direct-write
laser annealing. Through transmission electron microscopy, resistivity, and second harmonic measurements, the continuous transformation of the crystalline phase of W films from the highly
spin-orbit coupled, high resistivity $\beta$ phase to the minimally
spin-orbit coupled, low resistivity $\alpha$ phase is tracked with increasing
laser fluence. Gradients with different steepness are patterned in the tungsten phase to create
spin-orbit torque channels and, when interfaced with CoFeB, tungsten wires with a sufficiently strong gradient can switch the magnetization without an applied
magnetic field. Therefore, exploiting the unique microstructure of mixed-phase W allows precise control of the local electronic current density and direction, as well as local
spin-orbit torque efficiency, providing a new avenue for the design of efficient spintronic devices.
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All authors Lauren J. Riddiford, Anne Flechsig, Shilei Ding, Emir Karadza, Niklas Kercher, Tobias Goldenberger, Elisabeth Müller, Pietro Gambardella, Laura J. Heyderman, Aleš Hrabec