Soft Condensed Matter
Collective Ring Formation in Active Matter
Debraj Dutta and Urna Basu
We study the formation of ring-like structures in interacting active particle systems in two dimensions. The emergent structure shows signatures of both spatial and orientational organization. The spatial organization is characterized by the radial distance of a tagged particle from the centroid of the assembly, while orientational organization is characterized by the radial
alignment of its self-propulsion direction. We derive exact analytical expressions for the radial and polarization distributions for systems of active Brownian particles and run-and-tumble particles. While both models exhibit annular steady states, we show that their spatial and orientational organization differ qualitatively in the strongly active regime. A direct comparison of the two models reveals how the nature of the propulsion mechanism leads to the distinction in both the structure of the annulus and the statistics of particle orientations. Our results provide a unified analytical framework for characterizing emergent annular states in active matter and identify robust signatures that distinguish persistent active dynamics with continuous and discrete reorientation.
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Materials Science
The crystallographic quaternions and their product law
Cyril Cayron
Unit quaternions are widely used in science to encode rotations because the quaternion product is more efficient than
matrix product and more stable than Rodrigues product to calculate the composition of two rotations. However, quaternions in their usual form refers to a Cartesian basis; they cannot be used in crystallography as they are. The usual way to solve this issue to apply back-and-forth coordinate changes from the
crystal basis to a Cartesian basis attached to the
crystal with the help of the structure tensor. Here, we show that actually quaternions can be used directly in the
crystal basis by generalizing the quaternion product law. In that aim, we introduced a
matrix that we called cross tensor. It allows the calculation of the cross product in the
crystal basis, a bit like the metric tensor allows it for the scalar product. We also show the cross tensor is proportional to the inverse of the metric tensor. The formula of crystallographic quaternion product is then given; it depends uniquely on the metric tensor. The application of the crystallographic quaternions to Electron Back Scatter Diffraction is discussed.
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Materials Science
Planar Microcavities can Suppress Exciplex Formation and Increase the Emission Efficiency of Organic Semiconductors
Tomohiro Ishii and Stéphane Kéna-Cohen
Optical microcavities are widely used to control the emission of organic
semiconductors, but their ability to reshape the molecular pathways that precede emission remains largely unexplored. Here we show that
embedding a ZnPc:TPBi blend in a planar Fabry-Pérot microcavity suppresses the formation of non-radiative exciplexes and removes bimolecular annihilation at high excitation densities, increasing the photoluminescence
quantum yield by more than forty-fold under continuous-wave excitation. This enhancement is far larger than expected from the weak Purcell effect. Instead, transient spectroscopy, power-dependent photoluminescence and kinetic modelling point to a cavity-induced rebalancing of excited-state populations: long-range Förster energy transfer from ZnPc monomers to emissive aggregates is enhanced, allowing it to outcompete charge transfer to dark exciplexes. Electromagnetic calculations predict FRET enhancements of up to ~400-fold at relevant distances, consistent with the observed suppression of exciplex-mediated losses. Our results show that optical cavities can control not only how molecules emit, but also which excited states they form, opening a route to improved efficiency and reduced roll-off in organic optoelectronic and photonic devices.
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Disordered Systems and Neural Networks
Point Group Equivariant Graph Neural Networks for Materials
Alexander J. Heilman and Qimin Yan
Equivariant graph neural networks have proven effective tools for inference of material's properties directly from their structure. Traditionally, these have been applied such that they respect full $O(3)$ equivariance, so that any rotation or reflection of the input structure is respected in the model's output. While this works for general arrangements of atoms, additional
symmetries of atomistic systems are left unleveraged. Furthermore, any
symmetries of the filter functions are implicitly learned from the full
dataset and not strictly enforced. In this work, we introduce point-group
symmetry aware equivariant graph neural networks (PGEqNN) for materials science, with filter functions aligned with
symmetry-aware indices for greater granularity in predictive tasks. With this architecture, we show that most of the predictive power of equivariant networks for tensorial elastic and dielectric
datasets lies in the trivial subspaces of the point-group adapted bases. Exploiting this, an $A_1$-restricted variant matches or improves on its full point-group and $SO(3)$-partitioned counterparts while training fewer active parameters, yielding leaner models of equal accuracy.
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Materials Science
Operando observation of strain relaxation in fatigued pearlitic steel
Louis Lesage, Johan Ahlström, Yubin Zhang et al. (+1 more)
Pearlitic steels are the material of choice for railway wheels and rails, where their lamellar ferrite-cementite structure balances cost, strength, and wear resistance. However, in use, cyclic loading combined with frictional heat softens the steel, promoting fatigue and eventual failure. Here we use Dark-Field X-ray Microscopy (DFXM) to follow, operando, the grain-scale response of a fatigued pearlitic colony during annealing up to 550 {\deg}C. Orientation maps reveal negligible
lattice rotation and no sub-
cell formation, indicating that the cementite lamellae suppress long-range dislocation motion. Strain maps nonetheless show pronounced relaxation: the elastic strain spread narrows by nearly 40%, with recovery starting below 250 {\deg}C, within the operating temperatures of railway wheels. We attribute this relaxation to short-range annihilation of dislocations confined between lamellae, linking grain-scale strain recovery to the macroscopic softening of pearlitic railway steels in service.
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All authors Louis Lesage, Johan Ahlström, Yubin Zhang, Can Y{\i}ld{\i}r{\i}m
Materials Science
Specimen design for material parameter identification using topology optimization
Adeline Wihardja and Kaushik Bhattacharya
Constitutive relations close the equations of continuum mechanics, and serve as a surrogate for a material in the design and engineering process. They are often specified in a parameterized form with parameters identified by experiment. In this paper, we propose a framework for identifying experimental configurations that are maximally informative for material parameter discovery. The framework strongly couples modeling and experimentation: the model leverages high-dimensional data from full-field measurements, while the current uncertainty in the model guides the design of future experiments. We formulate this goal by integrating
Bayesian optimal experimental design with
topology optimization. The
Bayesian design criterion quantifies expected information gain, which drives the
topology optimization of the specimen geometry.
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Mesoscale and Nanoscale Physics · Cross-listed from quant-ph
Experimental Nanoscale Thermodynamics
G. Andrew D. Briggs and Jörg Schmiedmayer
Modern fabrication techniques have allowed artificial systems to be constructed on a nanometre length scale. The ideas underlying thermodynamics, a field invented to describe large macroscopic systems, need to be modified to describe much smaller systems. There are implications for our understanding of
entropy, cooling, the arrow of time, heat flow, engines, erasure, and mutual information. The theoretical concepts have been implemented and tested in a wide range of experiments, many of which are at low temperatures. Nanoscale thermodynamics is not only a descriptive tool of nanoscale systems, but a design principle that helps us to build new architectures, processors and learning machines.
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Materials Science
Electrical Control of Altermagnetism in a Quasi-1D Magnet
Alberto M. Ruiz, Cuiju Yu, Diego López-Alcalá et al. (+3 more)
Altermagnetism is a collinear
magnetic state characterized by momentum-dependent
spin splitting in fully compensated materials. While widely investigated in systems governed by three- or two-dimensional exchange interactions, its extension to quasi-one-dimensional magnets remains almost unexplored. Focusing on the experimentally established AgCrP$_2$S$_6$ van der Waals magnet, we demonstrate that
antiferromagnetic chains embedded in a two-dimensional
lattice provide a general route to altermagnetism. Combining first-principles calculations and
spin-space-group analysis, we show that out-of-plane
symmetry breaking can generate a nonrelativistic d-wave
spin splitting. An external out-of-plane electric field validates this mechanism, where the induced splitting increases linearly with field strength and reverses sign with field direction. We rationalize such behaviour by constructing an effective tight-binding model, which links the altermagnetic response to anisotropic third-neighbor interchain hoppings. Additionally, we show that Janus substitution also induces a d-wave
spin texture, while ferroelectric interfacing with CuInP$_2$S$_6$ enables polarization-controlled
spin-split bands in a fully compensated ferrimagnetic state. Our results establish quasi-one-dimensional antiferromagnets as building blocks for altermagnetism.
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All authors Alberto M. Ruiz, Cuiju Yu, Diego López-Alcalá, Jose L. Lado, Adolfo O. Fumega, José J. Baldoví
Superconductivity
Marginal-Fermi-Liquid-like Behavior without Pseudogap in Infinite-Layer Nickelates
Yu Fan, Zhitong An, Xiang Ding et al. (+10 more)
Pseudogap formation, strange-metal behavior and unconventional superconductivity are closely intertwined in hole-doped cuprates, yet their relationship remains unresolved. Infinite-layer nickelates offer a distinct 3d9-derived platform to address this question by combining a cuprate-like Ni dx2-y2
Fermi surface with multiband electronic degrees of freedom. Here we use angle-resolved photoemission spectroscopy to resolve the low-energy spectral function of superconducting La0.8Ca0.2NiO2 and parent LaNiO2 thin films. In La0.8Ca0.2NiO2, the electronic self-energy Im Sigma(omega) is approximately linear in energy and its slope increases from (pi/2, pi/2) to (pi, 0), revealing momentum-dependent marginal-
Fermi-
liquid-like scattering. Both films show a progressive suppression of low-energy spectral weight from the diagonal direction toward (pi, 0), with stronger suppression in parent LaNiO2. However, finite
Fermi-level spectral weight persists around the entire
Fermi surface, with no leading-edge shift or back-bending indicative of pseudogap formation in either the electron pocket or the cuprate-like hole band. Our results demonstrate that momentum-selective correlations and marginal-
Fermi-
liquid-like scattering can occur without a detectable cuprate-like pseudogap, providing a
benchmark for identifying the essential normal-state electronic ingredients of high-temperature superconductivity.
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All authors Yu Fan, Zhitong An, Xiang Ding, Xingtian Sun, Yutong Chen, Zhihui Chen, Shenglin Tang, Chihao Li, Jiahao Ye, Timur Kim, Haichao Xu, Rui Peng, Donglai Feng
Quantum Gases · Cross-listed from quant-ph
Geometric Qubits in Programmable Atomic Trimers
Julien Garaud and Antti J. Niemi
Motivated by programmable tweezer arrays, we develop an exactly solvable shape-space theory for near-equilateral atomic trimers. The
Higgs oscillator on Kendall's shape sphere gives a nonresonant spectral
lattice whose fixed-angular-momentum relative-stationary minimizers are supported on two adjacent admissible sites. These
symmetry-selected doublets are separated from higher relative-stationary branches by a finite branch gap. With phase-coherent shape-mode driving and Rydberg-mediated conditional phases, they furnish a candidate route to
geometric qubits and entangling operations.
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Mesoscale and Nanoscale Physics
Distributed Topological Charge and Spinorial Holonomy in Yukawa-Regularized Graphene Disclinations
A. M. de M. Carvalho, G. Q. Garcia, E. Brito et al. (+1 more)
Conical geometries provide the standard description of disclinations, but they concentrate the
curvature at a singular apex. We introduce a Yukawa-type regularization that replaces this singularity by a smooth
curvature distribution while preserving the asymptotic
topology of the defect. Exact expressions are obtained for the conformal factor,
curvature, and enclosed topological charge. The resulting geometry exhibits a scale-dependent topological charge and a corresponding radius-dependent holonomy, establishing a direct connection between distributed
curvature and
geometric phases. We further investigate the dynamics of massless Dirac quasiparticles in this background and show that the regularized core modifies the
spin connection while preserving the asymptotic topological signature of the defect. These results provide a finite-core extension of the conventional conical description and offer a natural framework for studying
geometric and topological effects in
graphene-like systems.
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All authors A. M. de M. Carvalho, G. Q. Garcia, E. Brito, C. Furtado
Quantum Gases
Two-dimensional solitons in extended GPE models with Lee-Huang-Yang corrections
G. N. Koutsokostas, F. Bristy, E. C. Psychogiou et al. (+5 more)
We investigate the existence and dynamics of two-dimensional solitary waves in a
quantum droplet environment described by the extended Gross-Pitaevskii equation featuring logarithmic mean-field and Lee-Huang-Yang interactions. In the modulationally stable regime of the background, we employ suitable multiscale asymptotic methods to derive effective nonlinear integrable models corresponding to the Kadomtsev-Petviashvili and Davey-Stewartson equations. Based on these reduced models, we construct approximate analytical solutions describing line
solitons, algebraically localized lump
solitons, ring
solitons, and exponentially localized dromions embedded on the droplet background. The dynamical robustness of these solutions is monitored through numerical simulations. Line, lump and ring
solitons stay closest to the theoretical predictions, although progressively deviate due to the emergence of small-amplitude radiation, while dromions depart from their analytical waveform the most, although they roughly maintain their shape. Our results unveil unprecedented multidimensional
soliton solutions in models featuring the competition of mean-field and
quantum fluctuations and as such are amenable to current ultracold atom experiments.
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All authors G. N. Koutsokostas, F. Bristy, E. C. Psychogiou, G. A. Bougas, G. C. Katsimiga, S. I. Mistakidis, P. G. Kevrekidis, D. J. Frantzeskakis
Soft Condensed Matter
Theory of associating polymers with annealed and quenched sticker disorder: Mean-field solution and phase behavior
Sofia Moschin, Achille Giacometti, Amos Maritan et al. (+1 more)
We develop a density-functional theory for solutions of associating
polymers where attractions among charged monomers (stickers) are represented by local binary degrees of freedom, which are randomly placed along the chains. Extending the original Garel and Orland's field-theoretic scheme for single-chain systems to an ensemble of interacting chains, we give the exact formulations of the model in both cases of annealed and quenched distributions of charges which we solve at the mean-field level. The solution produces qualitatively different free energy functionals. In the annealed case, the theory naturally yields a nontrivial scalar order parameter for the fraction of bonded sticker monomers and a self-consistent mass-action law at the saddle point. By contrast, in the quenched case no independent bonding order parameter emerges and the main effect is a renormalization of the effective two-body and three-body interaction parameters. The formulation is microscopic at the
Hamiltonian level and, within the same field-theoretic framework, provides a systematic starting point for fluctuation corrections beyond the mean-field approximation.
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All authors Sofia Moschin, Achille Giacometti, Amos Maritan, Angelo Rosa
Materials Science
Lattice initialisation and finite-size effects of non-equilibrium molecular dynamics simulations for heat transfer across graphene-copper interfaces
L.A. van Goor, W.N. Edeling, D. Jafari et al. (+5 more)
We study thermal transport across copper-
graphene-copper interfaces using Non-
Equilibrium Molecular Dynamics (NEMD), focusing on the influence of finite domain length and domain configuration, including
lattice initialisation and associated
graphene wrinkling, on the predicted thermal conductivity and Kapitza resistance. In the literature, NEMD simulations identified trends in the Kapitza resistance of
graphene-copper interfaces. However, the simulation outcomes and reliability may depend heavily on configuration choices that are underexplored in the literature. We identify a strong sensitivity of the Kapitza resistance to domain configuration choices that affect the
lattice constants and atomic density. We show that two conventional
lattice initialisation strategies yield a factor of two difference in the Kapitza resistance, despite differences of only a few per cent in the
lattice parameters. This behaviour is accompanied by strain-dependent shifts in the
graphene and copper
phonon spectra, and by increased
phonon overlap at lower strain. Counter to conventional expectations, greater
phonon-mode overlap coincides with higher Kapitza resistance, showing that spectral overlap alone cannot capture the interfacial heat-transfer dynamics. We suggest that in
lattices initialised with lower residual strain, a damping boundary layer develops near the interface, and increases thermal resistance, as indicated by increased local structural disorder and local spectral broadening over a wider interfacial region. Beyond strain- and density-related effects associated with the
lattice constants, Kapitza resistance shows no significant dependence on domain length or boundary temperature enforcement in this study. By contrast, the copper
lattice conductivity exhibits clear domain-size and temperature dependence, consistent with
phonon mean-free-path limitations and supported by
phonon spectral analysis.
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All authors L.A. van Goor, W.N. Edeling, D. Jafari, H. Lee, E. Luesink, W.W. Wits, A.V. Lyulin, B.J. Geurts
Statistical Mechanics · Cross-listed from math-ph
Approximate thermodynamics of the two-dimensional Ising model in an external magnetic field
Mathieu Gaudreault
We introduce approximate expressions for the thermodynamics of the two-dimensional Ising model in an external
magnetic field. The external field breaks the system's
symmetry, which complicates the exact calculation of the free energy. To address this, we write the model in its quaternion representation to apply a small angle approximation with respect to a reference frame. The approximation simplifies the transfer
matrix to a centrosymmetric
matrix for which the largest
eigenvalue is known and depends on the external field strength. We therefore write an approximate expression for the system's free energy and derive the magnetization, susceptibility, internal energy, and specific heat. These results are compared with numerical simulations performed with the BKL
algorithm. We find that the approximate expressions and numerical simulations agree in regions where the approximation is valid.
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Materials Science
Measuring momentum-resolved dissipation of phonon-polaritons in LiNbO$_3$ with terahertz driving
Megan F. Biggs, Rossella Acampora, Niccolò Sellati et al. (+5 more)
Mapping the dispersion of polaritons, hybrid quasiparticles arising from light-matter coupling, can provide key insights into the material dielectric response, coupling strength, and energy transfer pathways with other excitations. In this work, we present THz pump-Raman probe (TP-RP) as a versatile method for mapping the polariton dispersion in polar non-centrosymmetric materials, demonstrated here for the case of
phonon-polaritons in LiNbO$_3$. By resonantly driving polaritonic modes with a broadband THz pump and probing them with a tunable NIR Raman pulse, TP-RP allows for the extraction of the momentum-dependence of both their frequency and damping rate with high accuracy. The spectral features observed in the pump-probe signal, including the polaritonic response as well as pulse artifacts, are reproduced within a many-body theoretical approach. Applying the technique to study the E(TO$_1$)
phonon of LiNbO$_3$ enables the combined analysis of theory and experiments to uncover a nontrivial frequency dependence of the
phonon intrinsic damping rate, revealing possible anharmonic couplings to other modes.
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All authors Megan F. Biggs, Rossella Acampora, Niccolò Sellati, Mattia Udina, Lara Benfatto, Elsa Abreu, Steven L. Johnson, Jeremy A. Johnson
Soft Condensed Matter
Rolling pepper shaker on a slope
Mizuki Ono and Hirofumi Wada
Although the rolling of a solid object is a mundane phenomenon in our daily life, its movement can be surprisingly complex and physically rich, particularly when the solid object has certain internal degrees of freedom, such as a half-filled plastic bottle of water. The translational and rotational motion of such an object couple in a highly nontrivial manner, often leading to seemingly unpredictable trajectories. We use a combination of experimental and theoretical approaches to analyze the rolling behaviors of a rigid cylinder that is partially filled with granular media, rolling on an inclined plane. We experimentally find a wide variety of rolling behaviors, including damped oscillation leading to a stop, meandering with avalanches coming to a stop, in addition to the stationary rolling and rolling with a constant acceleration. We address the occurrence of substantial slip during rolling, in contrast to what is often assumed. We classify the rolling behavior into three distinct phases and establish a phase diagram. We theoretically explain the transition between stopping and rolling and rationalize the phase boundary based on the rigid-body mechanics combined with the statics of granular media. Our study addresses the curiosity to understand the everyday phenomena and has significant implications for a wide range of physical applications from powder manufacturing technologies to robotics.
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Materials Science
Period-dependent suppression of Fourier peaks for topography images: Analysis of periodicity of triple-step arrays on vicinal Si(h h m) surfaces
A. Yu. Aladyshkin, A. N. Chaika, V. N. Semenov et al. (+3 more)
Reliable determination of the periodicity of multiatomic steps on high-Miller-index vicinal surfaces is often complicated by (i) the presence of relatively narrow terraces tilted at large angles relative to the scanning plane, and (ii) unavoidable distortions in the lateral direction resulting from creep and improper calibration of a piezo scanner. This work paves a way to overcome these obstacles using the period-dependent
Fourier peaks suppression, which is invariant to affine distortions of the atomically resolved scanning probe microscopy images and to defects of the terrace atomic structure. We argue that the period of the triple-step arrays fabricated on vicinal Si(5 5 6) and Si(5 5 7) single-
crystal wafers can be determined from raw scanning tunneling microscopy data, without preliminary corrections, with precision approaching the interatomic distance. We demonstrate that the intensities of the
Fourier peaks in the differential maps, derived from raw topography images and containing stripes with the $7\times7$ reconstruction, strongly depend on the period of the stripes. The suppression of the ninth
Fourier peak indicates that the regular array of triple steps formed on the Si(5 5 7) wafers has a period of $18b=5.99$ nm in projection onto the Si(1 1 1) terrace plane, where $b=0.333$ nm is the distance between atomic rows of the $1\times 1$
lattice in the $[\bar{1} \bar{1} 2]$ direction. This means that the nominally (5\,5\,7)-oriented Si wafers may correspond locally to the Si(8 8 11) orientation. The method can be applied to the precise analysis of other vicinal surfaces with narrow and wide terraces containing an integer number of Si(1 1 1)$7\times7$ unit
cells.
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All authors A. Yu. Aladyshkin, A. N. Chaika, V. N. Semenov, A. S. Aladyshkina, A. M. Ionov, S. I. Bozhko
Superconductivity
Unconventional superconductivity in ScIr$_2$ chiral crystal with a kagome lattice
Keqi Xia, Jianzhou Zhao, Igor Plokhikh et al. (+6 more)
Materials with a kagome
lattice host exotic
quantum phenomena driven by the interplay between band
topology,
spin-orbit coupling, magnetism, and electronic correlations. While magnetism of kagome materials has been widely investigated, their unconventional superconductivity (SC) remains largely unexplored due to the limited availability of suitable materials. Here, we report evidence of unconventional SC in the ScIr$_{2-x}$Si$_{x}$ family by combining
muon-
spin spectroscopy measurements with band-structure calculations. The parent ScIr$_2$ undergoes a structural phase transition from a high-$T$ cubic- to a low-$T$ rhombohedral phase, while the Ir kagome layer remains, albeit slightly distorted. Although the structural transition is suppressed by Si substitution, the superconducting pairing of ScIr$_{2-x}$Si$_{x}$ remains well described by a two-gap model. Since at least one of the gaps has nodes, this indicates an unconventional SC. Its unconventional nature can be explained by the distinct flat bands occurring near the
Fermi level, leading to strong electronic correlations in the ScIr$_{2-x}$Si$_{x}$ family. Moreover, the low-$T$ phase of ScIr$_2$ exhibits an Ir
chiral chain; therefore, it can be classified as a topological
chiral crystal. Overall, the unusual properties of the ScIr$_{2-x}$Si$_{x}$ family make it an interesting, albeit rare, system for studying the interplay between unconventional SC, flat bands, and chirality.
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All authors Keqi Xia, Jianzhou Zhao, Igor Plokhikh, Marisa Medarde, Yang Xu, Qingfeng Zhan, Dariusz Jakub Gawryluk, Toni Shiroka, Tian Shang
Superconductivity
A Disconnected Superconducting Regime at the Parent Limit of Infinite-Layer Nickelates
Chihao Li, Yutong Chen, Yaolong Bian et al. (+11 more)
Infinite-layer nickelates have been widely viewed as cuprate analogs in which superconductivity emerges and forms a superconducting dome centered around 10-20% cation substitution. Here we show that pristine and stoichiometric PrNiO2, without cation substitution, exhibits intrinsic superconductivity characterized by zero resistance and diamagnetism in uncapped films. Through
heterostructure engineering, we further exclude an interfacial origin of the superconductivity. Remarkably, zero-resistance superconductivity is consistently observed in trivalent-substituted PrNiO2, whereas it is rapidly suppressed by dilute divalent substitution. Combined with angle-resolved photoemission studies, these results indicate that such a new superconducting regime is confined to within 3% additional hole doping from pristine PrNiO2. Furthermore, this phase is separated from the previously established superconducting dome around ~ 20% divalent doping by a non-superconducting region in the phase diagram, and is further distinguished by a remarkably stronger upper-critical-field anisotropy. These findings establish a unique separated superconducting regime, suggesting that infinite-layer nickelates are not merely cuprate analogs but host distinct superconducting physics.
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All authors Chihao Li, Yutong Chen, Yaolong Bian, Yihao Zhang, Jiahao Ye, Zhitong An, Xingtian Sun, Yu Fan, Zhihui Chen, Zhanze Wang, Jinglei Zhang, Haichao Xu, Rui Peng, Donglai Feng
Materials Science
Three Million Years Opposite State Data Retention in Partially Switched Wurtzite Ferroelectrics
Maike Gremmel, Roberto Guido, Victor Witte et al. (+3 more)
Ferroelectric
memories based on the wurtzite-structured ferroelectrics are projected to store information for more than 3 million years at 150C. These results are extracted by combining standard domain wall motion limited switching kinetics with the near-by-electrode injection model for opposite state retention in ferroelectric random access
memory. This impressive performance is greatly aided by switching only a fraction of the total polarization to store data, in order to limit the initial imprint variation of the devices - an effect that is universally observed in films with different thicknesses (60 nm - 270 nm) and different compounds (AlScN and AlScBN). Paradoxically, yet systematically, this reduction in initial imprint consistently results in larger switching polarization after a given time, compared to the fully switching state and 5-7 orders of magnitude improved opposite state retention. Finally, partial switching is able to simultaneously boost endurance against premature polarization loss and breakdown, making it a promising strategy for improved operation of ferroelectric devices with large spontaneous polarization, in particularly wurtzite-structured compounds.
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All authors Maike Gremmel, Roberto Guido, Victor Witte, Thomas Mikolajick, Uwe Schröder, Simon Fichtner
Strongly Correlated Electrons
Tuning superconducting pairing symmetry via a staggered potential in the doped honeycomb Hubbard model
Yanmei Cai, Yicheng Xiong, Ying Liang et al. (+1 more)
The ability to control superconducting pairing
symmetry is crucial for designing unconventional and topological
superconductors, yet practical tuning parameters beyond chemical doping remain limited. In this study, we investigate the effect of a tunable sublattice staggered potential on the pairing
symmetry in the doped honeycomb Hubbard model. Determinant
quantum Monte Carlo at finite temperature and constrained-path
quantum Monte Carlo at zero temperature are employed to compute
spin susceptibilities and pairing correlations in different channels. We find that increasing the staggered potential suppresses
antiferromagnetic fluctuations and, at low doping, induces a transition in the dominant pairing tendency from $d+id$-wave to $f_n$-wave, with consistent results from both
quantum Monte Carlo methods. In contrast, at higher doping levels, the system remains dominated by $d+id$-wave pairing even under an enhanced staggered potential. Moreover, strengthening the on-site interaction $U$ enhances the dominant pairing channel, underscoring the essential role of electronic correlations. Our results establish the staggered potential as a practical band-engineering tool for selecting unconventional pairing
symmetries without varying the doping concentration, providing inspiration for designing
graphene-based artificial
superconductors and related doped band
insulators such as Li${}_x$MNCl.
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All authors Yanmei Cai, Yicheng Xiong, Ying Liang, Tianxing Ma
Statistical Mechanics · Cross-listed from quant-ph
$p$-Body $\simeq$ Range $p-1$: Exact Order-Range Mapping and Dual-Unitarity
Tanay Pathak
We introduce and study a periodically kicked version of a one-dimensional
spin-$1/2$ Ising model with contiguous $p$-body interactions. At specific interaction strengths of the model, we establish an exact Floquet interaction $\textit{order-range}$ mapping: the Floquet
evolution operator of the $p$-body Ising model is exactly mapped to a two body Ising model with interactions having maximum range $p-1$ and exactly determined couplings. Upon further tuning the kicking strength, the mapped model becomes dual-
unitary, thus providing an explicit family of $p$-body dual
unitary models. We then determine exact
entanglement dynamics of the $p$-body model for a class of solvable initial states at all times. We further illustrate the nontrivial structures that can emerge from the $\textit{order-range}$ mapping using a minimal example of $p=3$ and generalize it for all odd $p$. These findings provide a systematic route to constructing and studying $p$-body dual-
unitary Floquet models.
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Statistical Mechanics
On the Information Required for Feedback Control
Matthew P. Leighton, Jose M. Betancourt, Thierry Emonet et al. (+2 more)
Biological systems across scales, along with many engineering problems, must control noisy systems with limited information. Here we study information-limited feedback control of
stochastic systems to achieve target steady states, and derive a lower bound on the information rate from controlled system to controller. This framework allows us to obtain performance-information Pareto frontiers for wide-ranging control problems with limited information. For systems with state-independent passive dynamics, the bound is saturated by an explicit optimal control protocol which probabilistically time-reverses the passive dynamics. We showcase these results through applications to nonlinear particle localization, microbial
navigation, and experimentally realized information engines.
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All authors Matthew P. Leighton, Jose M. Betancourt, Thierry Emonet, Benjamin B. Machta, Michael C. Abbott
Materials Science
High-entropy perovskites, architectured by s0/d0/d10 cations, as novel electrolytes for solid oxide fuel cells
Ho Truong Nam Hai, Rishad Kunafiev, Kwati Leonard et al. (+1 more)
Solid
oxide fuel
cells enable efficient conversion of hydrogen into electricity. However, the limited availability of materials for their cathode, anode, and electrolyte remains a concern. This study introduces three high-
entropy oxide perovskites as novel electrolyte materials for fuel
cells (Ba0.50Sr0.50)(Ti0.33Zr0.33Hf0.33)O3 with s0/d0 cations, (Ba0.50Sr0.50)(Ga0.33In0.33Sn0.33)O3 with s0/d10 cations, and (Ba0.50Sr0.50)(Ti0.33Zr0.33Sn0.33)O3 with mixed s0/d0/d10 cations. Through sequential sintering by high-pressure torsion processing and calcination, these perovskites were synthesized and then printed with a thickness of about 6-10 microns on a Ni-SrZr0.5Ce0.4Y0.1O3 substrate as an anode and then coated with Ba0.5La0.5CoO3 as a cathode. Electrochemical analysis and impedance spectroscopy show that (Ba0.50Sr0.50)(Ti0.33Zr0.33Sn0.33)O3 with s0/d0/d10 cations exhibits the best performance with negligible current leakage and lowest ohmic resistance, while its maximum power density reaches 0.53 W.cm-2 at 973 K. Complementary synchrotron X-ray absorption and photoelectron spectroscopy analyses indicate that the superior performance of (Ba0.50Sr0.50)(Ti0.33Zr0.33Sn0.33)O3 correlates with its heterogeneous electronic structure characterized by tailored unoccupied d-orbital states, and favorable local metal-oxygen bond lengths and extrinsic oxygen vacancies. This investigation demonstrates the significance of high-
entropy perovskites with mixed s0/d0/d10 cations as new rare-earth metal-free ion-conducting electrolytes, particularly for protonic solid
oxide fuel
cells.
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All authors Ho Truong Nam Hai, Rishad Kunafiev, Kwati Leonard, Kaveh Edalati
Materials Science
Beyond Janus Atomic Ordering: High-Throughput First-Principles Search for Hidden MoSO Monolayer Structures
Zhijing Huang, Tingting Zeng, Lin Zhang et al. (+5 more)
Despite the growing interest in two-dimensional (2D) MoSO systems, existing studies have exclusively focused on conventional Janus structures. In this work, we perform high-throughput first-principles calculations to explore novel stable 2D MoSO monolayers. Combined with random sampling strategy, graph theory and group theory, we successfully screen out three novel non-Janus 2D MoSO monolayers from 1325 candidate structures, namely Reversed 2H-MoSO, Hybrid 2H-MoSO, and Hybrid 1T'-MoSO. Compared with Janus MoSO monolayers, the non-Janus MoSO counterparts possess lower binding energies, varying from -4.38 to -4.51 eV/atom. A systematic combination of dynamic, thermodynamic, and mechanical stability analyses corroborates their excellent structural robustness. Ab initio molecular dynamics (AIMD) simulations confirm their superior thermal resistance, with the structures remaining stable at temperatures beyond 2000 K. Interestingly, unlike the semiconducting Janus MoSO, the Hybrid 1T'-MoSO monolayer exhibits distinct metallic characteristics. Furthermore, we found that strain and
curvature can enable controlled phase transitions of MoSO among semiconducting, semimetallic, and metallic phases. More importantly, the Hybrid 1T'-MoSO exhibits favorable HER activity with a Gibbs free energy of -0.002 eV, rendering it a promising candidate for hydrogen
evolution catalysis. This work not only expands the family of 2D MoSO materials but also provides a reliable strategy for discovering stable functional 2D materials via high-throughput computation.
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All authors Zhijing Huang, Tingting Zeng, Lin Zhang, Zhibin Gao, Longyuzhi Xu, Li Yang, Shuming Zeng, Zonglin Gu
Soft Condensed Matter
3D Topologically Polarized Elastic Metamaterials Enable Asymmetric Energy Isolation at Low Frequencies
Shaoyuan Zhang, Xuejian Gong, Fangyuan Ma et al. (+5 more)
Topologically polarized elasticity has been extensively studied in lower-dimensions, yet its three-dimensional (3D) counterpart remains largely unexplored. Here, we demonstrate omnidirectional topological elasticity in 3D structures that incorporate bending stiffness, which elevates zero-frequency topological mechanical states into finite-frequency phononic modes. These modes are localized at a single boundary, creating a pronounced stiffness contrast in both static and finite-frequency dynamic regimes. This three-dimensional structure exhibits highly polarized mechanical behavior across all spatial dimensions, establishing omnidirectional asymmetric topological elasticity. Experimental and numerical results confirm robust, asymmetric energy isolation, arising from the interplay between bulk topological polarization and boundary-localized surface modes. Our findings establish a paradigm for 3D metamaterials, with promising applications in vibration shielding and directional wave manipulation.
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All authors Shaoyuan Zhang, Xuejian Gong, Fangyuan Ma, Zheng Tang, Ying Wu, Di Zhou, Feng Li, Yugui Yao
Materials Science
Harnessing disorder to decouple extension and shear in kirigami metamaterials
Haomin Yu, Hanxun Jin, Mingxuan Bi et al. (+5 more)
Kirigami turns stiff sheets into compliant, shape-morphing structures, but its reliance on periodic cut patterns comes at a cost: correlated panel rotations couple extension to shear, so stretching one axis drives a parasitic shear that cannot be suppressed, and also confine anisotropic stiffness to a narrow, discrete set of responses that cannot be tuned independently. Biological tissues overcome an analogous constraint through controlled disorder, such as graded fiber orientations in skin and hierarchical anisotropy in myocardium, achieving direction-dependent mechanics unavailable to regular architectures. Here, we show that engineered disorder is a design degree of freedom for kirigami, with
stochastic kirigami accessing a continuous and far broader region of mechanical response than periodic patterns. This includes programmable anisotropy with near-complete elimination of extension-shear coupling. Because disordered patterns lack a simple parameterization, we navigate this design space with a geometry-aware graph neural network (GNN) that maps cut
topology to the full nonlinear, bidirectional stress-strain response, coupled to a genetic
algorithm that inverse-designs patterns reproducing target responses along two perpendicular axes. The GNN trains an order of magnitude faster and more accurately than image-based models. Fabricated elastomer samples reproduce the predicted nonlinear, anisotropic responses, closing the loop from design to physical component. By turning disorder into a variable to control directional stiffness, this work develops architected materials that stretch without parasitic shear, from soft actuators to tissue-interfacing devices matched to the anisotropy of living tissue.
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All authors Haomin Yu, Hanxun Jin, Mingxuan Bi, Mohammad Jafari, Feng Helen Long, Michael J Greenberg, Farid Alisafaei, Guy Genin
Materials Science
Ordinary Disordered Materials Can Carry Hyperuniform Physical Fields
Liyu Zhong, Haina Wang and Yang Jiao
Fluctuations in disordered matter play a central role in determining material properties and physical responses. Recent studies have identified an exotic class of systems known as structurally hyperuniform materials, in which large-scale density fluctuations are anomalously suppressed through special spatial organization of particles, phases, or microstructural features. Here we demonstrate that ordinary, structurally nonhyperuniform disordered materials can nevertheless support hyperuniform physical scalar, vector, and tensor fields such as charge, bound current, vorticity, defect density, and stress. We develop a general theoretical framework in which a physical field is generated from a more primitive parent field through a local physical operator. In
Fourier space, the spectrum of the derived field is determined by the product of the parent-field spectrum and the
Fourier symbol of the operator. When the operator embodies a local gauge-like constraint, its
Fourier symbol possesses zeros at small wavenumber, eliminating the corresponding long-wavelength fluctuations. As a consequence, the derived field exhibits complete suppression of infinite-wavelength intensity fluctuations, irrespective of the large-scale disorder and nonhyperuniformity of the parent field. We demonstrate this mechanism in elastic, electrostatic, and magnetostatic settings, showing that operator-generated incompatibility, bound charge, and bound-current fields can become hyperuniform even when their parent eigenstrain, polarization, or magnetization fields remain conventionally disordered. These findings broaden the notion of hyperuniformity from a structural property of matter to a universal field phenomenon generated by local physical constraints.
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Mesoscale and Nanoscale Physics
Topological magnon noises
Shuang Liang, Tengyue Zhao, Yu-Hang Li et al. (+1 more)
We develop a comprehensive formalism for
magnon transport in
ferromagnetic insulators driven by a temperature gradient. The formulas for
magnon current and corresponding
magnon noise are derived herein based on the
spin Hamiltonian of a topological
magnon insulator, which enables us to calculate the
magnon Hall angle, to provide an explicit expression for the Fano factor, and to reaffirm the quantitative relations between
magnon conductance and
magnon noise. We find that the
magnon current is not conserved in the presence of the Gilbert damping. Consequently, the reciprocal relation between the local and nonlocal noises, the Johnson-Nyquist formula between the conductance and the thermal noise, and the relation between the transmission coefficient and the shot noise are profoundly altered.
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All authors Shuang Liang, Tengyue Zhao, Yu-Hang Li, Hua Jiang