CMP Journal 2025-05-05
Statistics
Nature Nanotechnology: 1
Nature Physics: 1
arXiv: 45
Nature Nanotechnology
Electromagnetic wireless remote control of mammalian transgene expression
Original Paper | Biomaterials | 2025-05-04 20:00 EDT
Zhihua Lin, Preetam Guha Ray, Jinbo Huang, Peter Buchmann, Martin Fussenegger
Communication between wireless field receivers and biological sensors remains a key constraint in the development of wireless electronic devices for minimally invasive medical monitoring and biomedical applications involving gene and cell therapies. Here we describe a nanoparticle-cell interface that enables electromagnetic programming of wireless expression regulation (EMPOWER) of transgenes via the generation of cellular reactive oxygen species (ROS) at a biosafe level. Multiferroic nanoparticles coated with chitosan to improve biocompatibility generate ROS in the cytoplasm of cells in response to a low-frequency (1-kHz) magnetic field. Overexpressed ROS-responsive KEAP1/NRF2 biosensors detect the generated ROS which is rewired to synthetic ROS-responsive promoters to drive transgene expression. In a proof-of-concept study, subcutaneously implanted alginate-microencapsulated cells stably expressing an EMPOWER-controlled insulin expression system normalized blood-glucose levels in a mouse model of type 1 diabetes in response to a weak magnetic field.
Biomaterials, Bionanoelectronics, Biosensors, Nanoparticles
Nature Physics
Robust and resource-optimal dynamic pattern formation of Min proteins in vivo
Original Paper | Biophysics | 2025-05-04 20:00 EDT
Ziyuan Ren, Henrik Weyer, Michael Sandler, Laeschkir Würthner, Haochen Fu, Chanin B. Tangtartharakul, Dongyang Li, Cindy Sou, Daniel Villarreal, Judy E. Kim, Erwin Frey, Suckjoon Jun
The Min protein system prevents abnormal cell division in bacteria by forming oscillatory patterns between cell poles. However, predicting the protein concentrations at which oscillations start and whether cells can maintain them under physiological perturbations remains challenging. Here we show that dynamic pattern formation is robust across a wide range of Min protein levels and variations in the growth physiology using genetically engineered Escherichia coli strains. We modulate the expression of minCD and minE under fast- and slow-growth conditions and build a MinD versus MinE phase diagram that reveals dynamic patterns, including travelling and standing waves. We found that the natural expression level of Min proteins is resource-optimal and robust to changes in protein concentration. In addition, we observed an invariant wavelength of dynamic Min patterns across the phase diagram. We explain the experimental findings quantitatively with biophysical theory based on reaction-diffusion models that consider the switching of MinE between its latent and active states, indicating its essential role as a robustness module for Min oscillation in vivo. Our results underline the potential of integrating quantitative cell physiology and biophysical modelling to understand the fundamental mechanisms controlling cell division machinery, and they offer insights applicable to other biological processes.
Biophysics, Microbiology
arXiv
Novel entangled dimer state in the Shastry-Sutherland magnet Yb$_2$Be$_2$SiO$_7$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-05 20:00 EDT
A. Brassington, Q. Ma, G. Duan, S. Calder, A.I. Kolesnikov, K.M. Taddei, G. Sala, H. Wang, W. Xie, B.A. Frandsen, N. Li, X.F. Sun, C. Liu, R. Yu, H.D. Zhou, A.A. Aczel
The Shastry-Sutherland lattice (SSL) magnet, with antiferromagnetic intradimer and interdimer Heisenberg exchange, is known to host an antisymmetric singlet ground state when the intradimer exchange is dominant. Rare-earth-based SSL systems with strong spin-orbit coupling offer the opportunity for tuning their magnetic properties by using magnetic anisotropy as a control knob. Here, we present bulk characterization and neutron scattering measurements of the SSL material Yb$ _2$ Be$ _2$ SiO$ _7$ . We find that the Yb$ ^{3+}$ ions can be described by an effective spin-1/2 model at low temperatures and the system does not show signs of magnetic order down to 50 mK. The magnetization, heat capacity, and neutron spectroscopy data can be well-described by an isolated dimer model with highly anisotropic exchange that stabilizes a singlet ground state with the symmetric wavefunction up/up - down/down. Our results show that strong spin-orbit coupling can induce novel entangled states of matter on the SSL.
Strongly Correlated Electrons (cond-mat.str-el)
9 pages, 4 figures, and SM
Anisotropic Spin Ice on a Breathing Pyrochlore Lattice
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-05 20:00 EDT
Gloria Isbrandt, Frank Pollmann, Michael Knap
Spin ice systems represent a prime example of constrained spin systems and exhibit rich low-energy physics. In this study, we explore how introducing a tunable anisotropic spin coupling to the conventional Ising spin ice Hamiltonian on the breathing pyrochlore lattice affects the ground state properties of the system. Significant changes are observed in the ground state structure, reflected in the spin structure factor and in a reduction of residual entropy at low temperatures. We theoretically uncover a rich phase diagram by varying the anisotropy and demonstrate how this modification reduces the ground state degeneracy across different phases. Numerical simulations reveal that, at sufficiently low temperatures, the system either undergoes a crossover into a constrained spin ice manifold, characterized by an entropy density that drops below the Pauling entropy of conventional spin ice, or a phase transition into a symmetry-broken state, depending on the perturbations. Additionally, we compute the spin structure factors for the anisotropic model and compare these results to analytical predictions from a large-$ N$ expansion, finding good agreement. This work develops the understanding of spin ice in anisotropic limits, which may be experimentally realized by strain, providing, among others, key signatures in entropy and specific heat.
Strongly Correlated Electrons (cond-mat.str-el)
Real-space orbital tiling approach for the design of novel superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-05 20:00 EDT
Gregory Bassen, Wyatt Bunstine, Rebecca Han, Ragy Ebeid, Eli Zoghlin, Tyrel M. McQueen
Despite substantial advances in the field, we still lack a predictive framework capable of guiding the discovery of new families of superconductors. While momentum-space approaches have advanced the microscopic understanding of superconductivity, they offer limited guidance for materials design based on atomic building blocks. Here, we propose a real-space framework which conceptualizes Cooper pairs as confined standing waves resulting from coherent tilings of atomic orbitals. We call this model the Real-space Orbital Superconducting Pathway (ROSP). Using a tight-binding toy model, we show that the energetics of electron pairing depend on the configuration and overlap of real-space orbitals, which motivates \textit{a priori} design of superconducting families from orbital tiling. We connect the ROSP model to Roald Hoffmann’s isolobal analogy to classify families of superconductors based on shared orbital tilings, rather than structure or electron count. As an example, we suggest that superconductivity in La$ _{3}$ Ni$ _{2}$ O$ _{7}$ and LaNiO$ _{2}$ , despite differing structures and electron counts, may arise from a common ROSP. We introduce a new notation to classify two-dimensional square-net ROSPs and further propose several new families of superconductors on the anti-cuprate lattice. This framework provides a new model for predicting and designing families of high-T$ _c$ superconductors from real-space orbital architecture, even without microscopic knowledge of the attractive pairing interaction.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
17 pages, 11 figures, submitted to Journal of Physics: Condensed Matter
Free-energy perturbation in the exchange-correlation space accelerated by machine learning: Application to silica polymorphs
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-05 20:00 EDT
Axel Forslund, Jong Hyun Jung, Yuji Ikeda, Blazej Grabowski
We propose a free-energy-perturbation approach accelerated by machine-learning potentials to efficiently compute transition temperatures and entropies for all rungs of Jacob’s ladder. We apply the approach to the dynamically stabilized phases of SiO$ _2$ , which are characterized by challengingly small transition entropies. All investigated functionals from rungs 1-4 fail to predict an accurate transition temperature by 25-200%. Only by ascending to the fifth rung, within the random phase approximation, an accurate prediction is possible, giving a relative error of 5%. We provide a clear-cut procedure and relevant data to the community for, e.g., developing and evaluating new functionals.
Materials Science (cond-mat.mtrl-sci)
Beyond kagome: $p$-bands in kagome metals
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-05 20:00 EDT
Alexander A. Tsirlin, Ece Uykur
We review recent studies on quantum materials where transition-metal atoms give rise to $ d$ -bands typical of kagome metals. Using examples from several material families - AV$ _3$ Sb$ _5$ , FeGe, RV$ _6$ Sn$ _6$ , and LaRu$ _3$ Si$ _2$ - we argue that $ p$ -bands contributed by elements beyond the kagome network also play a crucial role in the electronic instabilities, including the charge-density-waves and superconductivity in kagome metals.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci), Superconductivity (cond-mat.supr-con)
Perspective for Advanced Quantum Technologies; comments and suggestions are welcome!
Dynamical Cluster Approximation for Disordered Systems with Rashba Spin-Orbit Coupling
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-05-05 20:00 EDT
Yongtai Li, Gour Jana, Chinedu E. Ekuma
We present an extension of the dynamical cluster approximation (DCA) that incorporates Rashba spin-orbit coupling (SOC) to investigate the interplay between disorder and SOC on a two-dimensional square lattice. By analyzing the average density of states and the self energy, we demonstrate how Rashba SOC modifies single-particle properties in the presence of nonlocal spatial correlations captured by DCA. The return probability exhibits signatures of SOC induced delocalization at finite times. To assess the accuracy of our approach, we benchmark the DCA results against those obtained from the numerically exact kernel polynomial method. The good agreement between the two methods validates the use of the computationally efficient, mean-field-based DCA framework for studying disordered systems with SOC.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
On recovering intragranular strain fields from grain-averaged strains obtained by high-energy X-ray diffraction microscopy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-05 20:00 EDT
C.K. Cocke, A. Akerson, S.F. Gorske, K.T. Faber, K. Bhattacharya
We address an unusual problem in the theory of elasticity motivated by the problem of reconstructing the strain field from partial information obtained using X-ray diffraction. Referred to as either high-energy X-ray diffraction microscopy(HEDM) or three-dimensional X-ray diffraction microscopy(3DXRD), these methods provide diffraction images that, once processed, commonly yield detailed grain structure of polycrystalline materials, as well as grain-averaged elastic strains. However, it is desirable to have the entire (point-wise) strain field. So we address the question of recovering the entire strain field from grain-averaged values in an elastic polycrystalline material. The key idea is that grain-averaged strains must be the result of a solution to the equations of elasticity and the overall imposed loads. In this light, the recovery problem becomes the following: find the boundary traction distribution that induces the measured grain-averaged strains under the equations of elasticity. We show that there are either zero or infinite solutions to this problem, and more specifically, that there exist an infinite number of kernel fields, or non-trivial solutions to the equations of elasticity that have zero overall boundary loads and zero grain-averaged strains. We define a best-approximate reconstruction to address this non-uniqueness. We then show that, consistent with Saint-Venant’s principle, in experimentally relevant cylindrical specimens, the uncertainty due to non-uniqueness in recovered strain fields decays exponentially with distance from the ends of the interrogated volume. Thus, one can obtain useful information despite the non-uniqueness. We apply these results to a numerical example and experimental observations on a transparent aluminum oxynitride (AlON) sample.
Materials Science (cond-mat.mtrl-sci), Analysis of PDEs (math.AP)
Intrinsic Chern Half-Metal with High Anomalous Hall Conductivity in 2D BaNiCl$_3$
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-05 20:00 EDT
Chidiebere I. Nwaogbo, Chinedu E. Ekuma
Two-dimensional (2D) half-metals offer complete spin polarization at the Fermi level, making them candidates for dissipationless spin transport. Yet intrinsic 2D half-metals exhibiting robust topological features, particularly large Chern number anomalous Hall conductivities, remain exceptionally rare. Using first-principles calculations, we identify atomically thin BaNiCl$ _3$ , a layered halide perovskite (perovskene), as a topological half-metal. It exhibits a high Chern number ($ C \ge 2$ ), a large anomalous Hall conductivity of 316~$ \Omega^{-1},\mathrm{cm}^{-1}$ , and a Fermi velocity of $ \approx 0.78 \times 10^6$ m/s. The coexistence of complete spin polarization and high carrier velocity suggests low-dissipation spin transport. Spin-orbit coupling opens a sizable topological gap of $ \sim 20,$ meV, yielding nontrivial Berry curvature and enhancing the anomalous Hall response. Ferromagnetism is stabilized by the Ni$ ^{2+}$ ($ d^8$ ) configuration and Cl-mediated superexchange, supporting magnetic ordering at elevated temperatures. These results establish BaNiCl$ _3$ as a rare intrinsic Chern half-metal, with potential applications in quantum and spintronic technologies.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Quantum Monte Carlo assessment of embedding for a strongly-correlated defect: interplay between mean-field and interactions
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-05 20:00 EDT
Kevin G. Kleiner, Sonali Joshi, Woncheol Lee, Alexander Hampel, Malte Rösner, Cyrus E. Dreyer, Lucas K. Wagner
Point defects are of interest for many applications, from quantum sensing to modifying bulk properties of materials. Because of their localized orbitals, the electronic states are often strongly correlated, which has led to a proliferation of quantum embedding techniques to treat this correlation. In these techniques, a weakly correlated reference such as density functional theory is used to treat most of the one-particle states, while certain states are singled out as an active space to be treated with an effective interaction. We assess these techniques in the context of an iron defect in aluminum nitride by referencing to a fully correlated quantum Monte Carlo description. This comparison allows us to have access to detailed information about the many-body wave functions, which are not available experimentally. We find that errors in the underlying density functional theory calculation, and thus choice of the active space, lead to qualitatively incorrect excited states from the embedded model. These errors are extremely difficult to recover from by adding corrections such as double counting or many-body perturbation theory.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
10 pages, 3 figures, 3 tables; includes Supplementary Material (15 pages, 6 figures, 9 tables)
The dynamical law behind eye movements: distinguishing between Lévy and intermittent strategies
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-05 20:00 EDT
Pedro Lencastre, Yurii Bystryk, Anis Yazidi, Sergey Denisov, Pedro G. Lind
Foraging is a complex spatio-temporal process which is often described with stochastic models. Two particular ones, Lévy walks (LWs) and intermittent search (IS), became popular in this context. Researchers from the two communities, each advocating for either Lévy or intermittent approach, independently analyzed foraging patterns and reported agreement between empirical data and the model they used. We resolve this Lévy-intermittent dichotomy for eye-gaze trajectories collected in a series of experiments designed to stimulate free foraging for visual information. By combining analytical results, statistical quantifiers, and basic machine learning techniques, we devise a method to score the performance of the models when they are used to approximate an individual gaze trajectory. Our analysis indicates that the intermittent search model consistently yields higher scores and thus approximates the majority of the eye-gaze trajectories better.
Statistical Mechanics (cond-mat.stat-mech)
Composition-dependent ultrafast luminescence in Cu-Ni alloys: Combined experimental and ab initio study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-05 20:00 EDT
Tohru Suemoto, Haruki Morino, Shota Ono, Tsuyoshi Okuno, Takeshi Suzuki, Kozo Okazaki, Shuntaro Tani, Yohei Kobayashi
Properties of Cu-Ni solid solutions have long been studied in physical and materials sciences. Yet, their many-body properties have not been well understood. Here, we investigate ultrafast luminescence in near infrared region for Cu$ _{1-x}$ Ni$ _x$ alloys. The luminescence intensity was the highest in Cu and decreased dramatically by adding Ni, approaching close to the value for pure Ni at $ x=0.45$ . This composition dependence was well reproduced by calculations assuming two body scattering of the energetic electrons. The luminescent decay rate was not straightforward, i.e., it decreased first by adding Ni up to $ x=0.17$ and then started to increase approaching twice the initial value at $ x=0.45$ . This behavior was in good agreement with ab initio calculations of electron-phonon (e-ph) coupling strength. This work provides a new perspective on the electron relaxation dynamics in solid solutions systems.
Materials Science (cond-mat.mtrl-sci)
6 pages, 3 figures
Magnetic excitons in non-magnetic CrCl3
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-05 20:00 EDT
Georgy Ermolaev, Tagir Mazitov, Anton Minnekhanov, Arslan Mazitov, Gleb Tselikov, Aleksandr Slavich, Alexey P. Tsapenko, Mikhail Tatmyshevskiy, Mikhail Kashchenko, Nikolay Pak, Andrey Vyshnevyy, Alexander Melentev, Elena Zhukova, Dmitriy Grudinin, Junhua Luo, Ivan Kruglov, Aleksey Arsenin, Sangen Zhao, Kostya S. Novoselov, Andrey Katanin, Valentyn S. Volkov
Van der Waals (vdW) materials, with their unique combination of electronic, optical, and magnetic properties, are emerging as promising platforms for exploring excitonic phenomena. Thus far, the choice of materials with exceptional excitonic response has been limited to two-dimensional (2D) configurations of vdW materials. At the same time, large interlayer distance and the possibility to create a variety of heterostructures offers an opportunity to control the dielectric screening in van der Waals heterostructures and van der Waal 3D materials, thus engineering the excitonic properties. Here, we reveal that bulk vdW crystal CrCl3 answers this quest with a record exciton binding energy of 1.64 eV owing to a delicate interplay of quasi-2D electronic confinement and short-range magnetic correlations. Furthermore, we observe colossal binding energies in vdW crystals NbOCl2 (0.66 eV) and MoCl3 (0.35 eV) and formulate a universal exciton binding energy dependence on bandgap for 2D and 3D vdW materials. Hence, our findings establish a fundamental link between the layered structure of vdW materials and their excitonic properties.
Materials Science (cond-mat.mtrl-sci), Optics (physics.optics)
15 pages, 5 figures
Projectification of point group symmetries with a background flux and Lieb-Schultz-Mattis theorem
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-05 20:00 EDT
Yasuhiro Tada, Masaki Oshikawa
We discuss the Lieb-Schultz-Mattis (LSM) theorem in two-dimensional spin systems with on-site $ {\mathrm U}(1)\rtimes {\mathbb Z}2$ spin rotation symmetry and point group $ C{2v}$ symmetry about a site. We ``twist” the point group symmetry by introducing a small uniform U(1) flux to obtain a projective symmetry, similarly to the familiar magnetic translation symmetry. The LSM theorem is proved in presence of the flux and then it is demonstrated that the theorem holds also for the flux-free system. Besides, the uniform flux enables us to show the LSM theorem for the time-reversal symmetry and the site-centered $ C_2$ -rotation symmetry.
Strongly Correlated Electrons (cond-mat.str-el)
14 pages, 10 figures
Sensitivity enhancement of an anomalous Hall effect magnetic sensor by means of second-order magnetic anisotropy
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-05 20:00 EDT
The sensing performance of anomalous Hall effect (AHE) magnetic sensors is investigated in terms of their sensitivity, the power spectrum of their voltage noise, and their detectivity. Special attention is paid to the effect of the second-order anisotropy constant, K2, on the sensing performance. It is found that the sensitivity is strongly enhanced by tuning the value of K2 close to the boundary between the in-plane magnetized state and the conically magnetized state. It is also found that the detectivity is almost independent of K2 as long as the film is in-plane magnetized. These results provide fundamental insights into the design of high-performance AHE sensors.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Current-induced Dynamics of Bloch Domain-wall Bimerons
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-05 20:00 EDT
Jiwen Chen, Laichuan Shen, Yan Zhou, Oleg A. Tretiakov, Xiaoguang Li
Domain-wall bimerons are composite topological structures formed by embedding bimerons within domain walls in ferromagnets with in-plane anisotropy. These hybrid textures have recently attracted significant attention due to their promise for racetrack memory applications. In this work, we systematically investigate the current-driven dynamics of single domain-wall bimerons and bimeron chains under spin-transfer torque (STT) and spin-orbit torque (SOT). We show that when the spin current is injected or polarized perpendicular to the domain wall, the bimeron Hall effect facilitates efficient motion along the wall. In contrast, spin currents injected or polarized parallel to the wall suppress transverse motion, leading to a significant reduction in the bimeron Hall angle. This anisotropic response is observed for both STT and SOT driving mechanisms. Furthermore, we find that increasing the number of bimerons within a domain wall diminishes their collective mobility. These results provide key insights into domain-wall bimeron dynamics and offer guidance for their integration into bimeron-based spintronic devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Non-Hermitian Haldane-Hubbard model: Effective description of an open system with balanced gain and loss
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-05 20:00 EDT
We study the correlated Haldane-Hubbard model with single-particle gain and loss, focusing on its non-Hermitian phase diagram and the ensuing non-unitary dynamic properties. The interplay of interactions and non-hermiticity results in insulating behavior with a phase diagram divided into three distinct regions, exhibiting either topologically gapped or (real) gapless regimes and a trivial phase. The latter is mapped by the emergence of a local order parameter associated with a charge density wave. A $ {\cal PT}$ -symmetry breaking at the low-lying spectrum occurs when increasing the gain-loss magnitude at a fixed interaction strength, marking the transition from gapped to gapless topological behavior. Further increase leads to the onset of charge ordering in a first-order phase transition in which level crossing takes place in the spectrum’s imaginary part. The support that the staggered gain and loss display to robust charge density wave in equilibrium is confirmed in the real-time dynamics in the presence of non-hermiticity, suggesting that engineered gain and loss can be used to tailor an ordered many-body state in experiments.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech)
9 pages, 6 figures
Bulk excitations in ultraclean $α$-RuCl$_3$: Quantitative evidence for Majorana dispersions in a Kitaev quantum spin liquid
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-05 20:00 EDT
Kumpei Imamura, Ryuichi Namba, Riku Ishioka, Kota Ishihara, Yuji Matsuda, Seunghun Lee, Eun-Gook Moon, Kenichiro Hashimoto, Takasada Shibauchi
The spin-orbit coupled Mott insulator $ \alpha$ -RuCl$ _3$ has emerged as a prime candidate for realizing the Kitaev quantum spin liquid (KQSL), characterized by Majorana quasiparticles, whose edge states exhibit a distinctive half-integer quantized thermal Hall conductivity. However, its van der Waals nature makes its thermal Hall response highly sensitive to structural disorder, leading to sample-dependent variations. Here, we investigate low-energy bulk excitations in the field-induced quantum disordered (FIQD) state of newly available ultraclean single crystals of $ \alpha$ -RuCl$ _3$ . High-resolution specific heat measurements under in-plane magnetic field rotation reveal an anisotropic excitation gap, whose field dependence is consistent with the Majorana gap in the KQSL state. Remarkably, when the field aligns with Ru-Ru bond directions, we observe gapless excitations with Dirac-like dispersions that quantitatively match theoretical predictions of Majorana bands based on the reported Kitaev interactions. Our findings in these ultraclean crystals provide strong evidence that the FIQD state of $ \alpha$ -RuCl$ _3$ is a robust KQSL, resilient against small disorder perturbations.
Strongly Correlated Electrons (cond-mat.str-el)
6 pages, 4 figures
Graph Neural Network-based structural classification of glass-forming liquids and its interpretation via Self-Attention mechanism
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-05 20:00 EDT
Kohei Yoshikawa, Kentaro Yano, Shota Goto, Kang Kim, Nobuyuki Matubayasi
Glass-forming liquids exhibit slow dynamics below their melting temperatures, maintaining an amorphous structure reminiscent of normal liquids. Distinguishing microscopic structures in the supercooled and high-temperature regimes remains a debated topic. Building on recent advances in machine learning, particularly Graph Neural Networks (GNNs), our study automatically extracts features, unveiling fundamental mechanisms driving structural changes at varying temperatures. We employ the Self-Attention mechanism to generate attention coefficients that quantify the importance of connections between graph nodes, providing insights into the rationale behind GNN predictions. Exploring structural changes with decreasing temperature through the GNN+Self-Attention using physically-defined structural descriptors, including the bond-orientational order parameter, Voronoi cell volume, and coordination number, we identify strong correlations between high attention coefficients and more disordered structures as a key indicator of variations in glass-forming liquids.
Soft Condensed Matter (cond-mat.soft)
9pages, 5 figures for main text, 12 pages for Supplementary Material
Chirality-selective proximity effect between chiral $p$-wave superconductors and quantum Hall insulators
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-05 20:00 EDT
Ryota Nakai, Koji Kudo, Hiroki Isobe, Kentaro Nomura
Heterostructures of superconductors and quantum-Hall insulators are promising platforms of topological quantum computation. However, these two systems are incompatible in some aspects such as a strong magnetic field, the Meissner effect, and chirality. In this work, we address the condition that the superconducting proximity effect works in the bulk of quantum Hall states, and identify an essential role played by the vortex lattice regardless of pairing symmetry. We extend this finding to a heterostructure of a chiral $ p$ -wave superconductor in the mixed state and an integer quantum Hall insulator. The proximity effect works selectively in the lowest Landau level depending on relative chiralities. If the chiralities align, a topological phase transition to a topological superconductor occurs.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
11 pages, 5 figures
Quasi-local Frustration-Free Free Fermions
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-05 20:00 EDT
Shunsuke Sengoku, Hoi Chun Po, Haruki Watanabe
Recent studies have revealed that frustration-free models, expressed as sums of finite-range interactions or hoppings, exhibit several properties markedly different from those of frustrated models. In this work, we demonstrate that, by relaxing the finite-range condition to allow for exponentially decaying hoppings, one can build gapped frustration-free systems that realize Chern insulators as well as quasi-degenerate ground states with finite-size splittings. Moreover, by permitting power-law decaying hoppings, we also construct a gapless band metal whose finite-size gap scales inversely with the system size $ L$ . These findings serve as an important step toward clarifying the general properties of frustration-free systems and those represented by tensor network states.
Strongly Correlated Electrons (cond-mat.str-el), Other Condensed Matter (cond-mat.other), Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
12 pages, 5 figures, 1 table
Excitation spectrum of vortex-lattice modes in a rotating condensate with a density-dependent gauge potential
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-05-05 20:00 EDT
Rony Boral, Swarup K. Sarkar, Matthew Edmonds, Paulsamy Muruganandam, Pankaj Kumar Mishra
We investigate the collective excitation spectrum of a quasi-2D Bose-Einstein condensate trapped in a harmonic confinement with nonlinear rotation induced by a density-dependent gauge field. Using a Bogoliubov-de Gennes(BdG) analysis, we show that the dipole mode frequency depends strongly on the nonlinear interaction strength, violating Kohn’s theorem. Further utilizing the variational analysis, we derive analytical expressions for the dipole and breathing modes, which suggests a strong dependence of the condensate’s width on the nonlinear rotation resulting from the density-dependent gauge potential. We identify four different vortex displacement modes – namely Tkachenko, circular, quadratic, and rational-whose frequencies are sensitive to the nonlinear rotation. In addition to the numerical analysis, we also derive an analytical expression for the Tkachenko mode frequency using a Hydrodynamic approach that agrees well with the frequencies obtained by the Fourier analysis of the transverse and longitudinal vortex dynamics induced by a Gaussian perturbation as well as the frequencies from the BdG excitation spectrum. Our findings also reveal that the excitation spectrum remain symmetric around the angular quantum number $ l=0$ , with modified energy splitting between $ l$ and $ -l$ as the nonlinear rotation changes from negative to positive values. Finally, we demonstrate that the surface mode excitation frequency increases (decreases) with an increase in the positive (negative) nonlinear rotation strength.
Quantum Gases (cond-mat.quant-gas), Atomic Physics (physics.atom-ph)
17 pages, 11 figures
Raman spectroscopy of anyons in generic Kitaev spin liquids
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-05 20:00 EDT
Optical probes have emerged as versatile tools for detecting exotic fractionalized phases in quantum materials. We calculate the low-energy Raman response arising from mobile, interacting Ising anyons (or visons) in the chiral Kitaev spin liquid perturbed by symmetry allowed interactions - a phase relevant to \rucl. under a magnetic field. At zero temperature, the two-anyon continuum response shows a leading power-law scaling of the intensity near the onset of the signal: $ I(\omega) \sim (\omega-E^0_{2\sigma})^{\frac{1}{8}}$ for linear and parallel-circular polarization channels, where $ E^0_{2\sigma}$ is the two-particle gap. Strong corrections due to short-range interactions arise at order $ \frac{1}{4}$ . For cross-circularly polarized channels, the scaling is given by $ I(\omega) \sim (\omega-E^0_{2\sigma})^{|l\pm 1/8|}$ , where the value of $ l=0,1,2$ is determined by the number of minima in the single anyon dispersion. The exponents are directly related to the topological spin of Ising anyons $ \theta_\sigma =\frac{\pi}{8}$ , describing their exchange statistics. Our theory generalizes to spectral probes of anyonic quasiparticles with multiple band minima in other quantum liquids. Interaction between anyons may also induce bound-states, resulting in sharp peaks that show strong polarization dependence.
Strongly Correlated Electrons (cond-mat.str-el)
13 pages of main text, 8 figures
Kinetic roughening transition of ice crystals and its implications during recrystallization
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-05 20:00 EDT
Jorge H. Melillo, Ido Braslavsky
The growth and morphology of ice crystals are highly sensitive to environmental conditions. Under atmospheric pressure, rapid growth from the liquid phase produces dendritic structures with sixfold symmetry. This morphology results from subtle variations in surface tension linked to crystallographic orientation, which guides arm growth under supercooled conditions. In contrast, slow growth yields disk-shaped crystals with rounded surfaces, suggesting surface roughness on all but the basal planes. Roughening is a thermodynamic phenomenon where a crystal surface becomes non-faceted due to the absence of a step-edge barrier, leading to large surface fluctuations. A kinetic roughening transition is a temperature-dependent shift in growth behaviour, in which faceted surfaces at low temperatures transform into rounded surfaces at higher temperatures. To observe slow growth at low temperatures, supercooling must be minimized, which can be achieved by lowering the melting point. This study investigates the kinetic roughening transition in ice crystals grown in dimethyl sulfoxide (DMSO) and proline-water solutions. Using cryomicroscopy and real-time image analysis, we identified a distinct roughening transition temperature (TR = -15.4 oC). At TR, the crystal growth morphology shifted from circular disks at higher temperatures to hexagonal plates at lower temperatures. This transition was solute-independent and governed primarily by temperature. Ice consistently melted as circular disks, regardless of temperature. Recrystallization experiments confirmed that crystals grew as hexagonal plates below TR but melted as disks. We also examined the influence of antifreeze protein III (AFPIII), which binds to specific crystallographic planes and modifies morphology through a distinct mechanism, effectively suppressing kinetic roughening
Materials Science (cond-mat.mtrl-sci), Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
Coarse-grained graph architectures for all-atom force predictions
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-05 20:00 EDT
We introduce a machine-learning framework termed coarse-grained all-atom force field (CGAA-FF), which incorporates coarse-grained message passing within an all-atom force field using equivariant nature of graph models. The CGAA-FF model employs grain embedding to encode atomistic coordinates into nodes representing grains rather than individual atoms, enabling predictions of both grain-level energies and atom-level forces. Tested on organic electrolytes, CGAA-FF achieves root-mean-square errors of 4.96 meV atom-1 for energy and 0.201 eV A-1 for force predictions. CGAA-FF significantly reduces computational costs, achieving about 22- and 14-fold improvements in simulation speed and memory efficiency, respectively, compared to the all-atom potential (SevenNet-0). Since this CGAA framework can be integrated into any equivariant architecture, we believe this work opens the door to efficient all-atom simulations of soft-matter systems.
Materials Science (cond-mat.mtrl-sci), Soft Condensed Matter (cond-mat.soft)
In-Situ Growth and Ionic Switching Behavior of Single-Crystalline Silver Iodide Nanoflakes
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-05 20:00 EDT
Amir Parsi, Abdulsalam Aji Suleiman, Doruk Pehlivanoğlu, Hafiz Muhammad Shakir, Emine Yeğin, T. Serkan Kasırga
Silver iodide (AgI) is a prototypical superionic conductor, undergoing a first-order phase transition at 147 Celsius that enables rapid ionic transport through its lattice, making it attractive for solid-state ionic devices. However, due to the presence of mobile Ag ions, controlled chemical vapor deposition (CVD) synthesis of high-quality AgI single crystals has remained largely unexplored. Here, we present the controllable synthesis of thin, single-crystalline {\beta}-AgI nanoflakes using a home-built CVD setup with real-time optical observation capability, offering insights into their nucleation and growth dynamics. We evaluate the material’s environmental stability through temperature-dependent photodegradation and Ag nanoparticle formation induced by electron beam irradiation. Electrical measurements on two-terminal devices with silver contacts demonstrate a remarkable six-order-of-magnitude resistance drop in lateral configurations at elevated temperatures, indicative of switchable ionic conductivity. Additionally, vertical device architectures exhibit clear memristive (resistive switching) characteristics, likely due to the formation of conductive filaments. Our work addresses the key synthesis challenges and highlights the unique electrical properties of thin AgI single crystals, suggesting its potential for innovative devices in unconventional computing, data storage, and advanced neuromorphic systems.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Interplay of asymmetry and fragmentation in the many-body tunneling dynamics of two-dimensional bosonic Josephson junctions
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-05-05 20:00 EDT
Anal Bhowmik, Rhombik Roy, Sudip Kumar Haldar
It is well known that the many-body tunneling of a bosonic condensate leads to (longitudinal) fragmentation along the tunneling direction. In this work, we prepare the initial ground state as a (transversely) fragmented system by introducing a barrier oriented orthogonally to the tunneling direction and allow it to tunnel through a two-dimensional longitudinally and transversely-asymmetric bosonic Josephson junctions. For a fixed barrier height, we find that the initial transversal fragmentation is essentially independent of the asymmetry along the tunneling direction but reduces when the asymmetry is oriented orthogonally to the junction. We investigate the interplay between the interference of fragmentations and asymmetry in the junction by analyzing the rate of density collapse in the survival probability, the uncertainty product, and the nontrivial dynamics of the occupation of the first excited orbital. The interference of fragmentations is quantified by the ratio between the reduction of transverse fragmentation and the development of longitudinal fragmentation. We show that asymmetry along the junction (orthogonal to the junction) delays (accelerates), compared to the symmetric potential, in obtaining the maximal interference of fragmentations. Notably, self-trapping opposes the interference, whereas a resonant tunneling condition enhances it. Overall, we demonstrate that the influence of asymmetry on the competition between longitudinal and transversal fragmentations, which together govern the macroscopic tunneling dynamics of interacting bosons, arises purely from the many-body effects and has no counterpart in the mean-field theory.
Quantum Gases (cond-mat.quant-gas), Atomic Physics (physics.atom-ph)
Quantum geometric ferromagnetism by singular saddle point
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-05 20:00 EDT
Taisei Kitamura, Hiroki Nakai, Akito Daido, Youichi Yanase
We propose ferromagnetism that occurs in electrons at a saddle point with band touching, which we call the singular saddle point. At the singular saddle point, the divergent quantum metric induces ferromagnetic correlation, and the logarithmic divergence of the density of states ensures ferromagnetism within Stoner theory. This is a prototypical example of quantum geometric ferromagnetism. The two-dimensional $ t_{2g}$ -orbital model accommodates the ferromagnetism by this mechanism, which is continuously connected to the exactly proven flat-band ferromagnetism.
Strongly Correlated Electrons (cond-mat.str-el)
6 pages, 6 figures, 1 table, and the End Matter
Snakes in the Plane: Controllable Gliders in a Nanomagnetic Metamaterial
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-05 20:00 EDT
Arthur Penty, Johannes H. Jensen, Ida Breivik, Anders Strømberg, Erik Folven, Gunnar Tufte
The magnetic metamaterials known as Artificial Spin Ice (ASI) are promising candidates for neuromorphic computing, composed of vast numbers of interacting nanomagnets arranged in the plane. Every computing device requires the ability to transform, transmit and store information. While ASI excel at data transformation, reliable transmission and storage has proven difficult to achieve. Here, we take inspiration from the Cellular Automaton (CA), an abstract computing model reminiscent of ASI. In CAs, information transmission and storage can be realised by the glider'', a simple structure capable of propagating while maintaining its form. Employing an evolutionary algorithm, we search for gliders in pinwheel ASI and present the simplest glider discovered: the snake’’. Driven by a global field protocol, the snake moves strictly in one direction, determined by its orientation. We demonstrate the snake, both in simulation and experimentally, and analyse the mechanism behind its motion. The snake provides a means of manipulating a magnetic texture in an ASI with resolution on the order of 100 nm, which could in turn be utilised to precisely control other magnetic phenomena. The integration of data transmission, storage and modification into the same magnetic substrate unlocks the potential for ultra-low power computing devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Emerging Technologies (cs.ET), Cellular Automata and Lattice Gases (nlin.CG)
On Simulating Thin-Film Processes at the Atomic Scale Using Machine Learned Force Fields
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-05 20:00 EDT
S. Kondati Natarajan, J. Schneider, N. Pandey, J. Wellendorff, S. Smidstrup
Atomistic modeling of thin-film processes provides an avenue not only for discovering key chemical mechanisms of the processes but also to extract quantitative metrics on the events and reactions taking place at the gas-surface interface. Molecular dynamics (MD) is a powerful computational method to study the evolution of a process at the atomic scale, but studies of industrially relevant processes usually require suitable force fields, which are in general not available for all processes of interest. However, machine learned force fields (MLFF) are conquering the field of computational materials and surface science. In this paper, we demonstrate how to efficiently build MLFFs suitable for process simulations and provide two examples for technologically relevant processes: precursor pulse in the atomic layer deposition of HfO2 and atomic layer etching of MoS2.
Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG)
35 pages, 18 figures
J. Vac. Sci. Technol. A 43, 033404 (2025)
Family-Vicsek universality of the binary intrinsic dimension of nonequilibrium data
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-05 20:00 EDT
Roberto Verdel, Devendra Singh Bhakuni, Santiago Acevedo
The intrinsic dimension (ID) is a powerful tool to detect and quantify correlations from data. Recently, it has been successfully applied to study statistical and many-body systems in equilibrium. Yet, its application to systems away from equilibrium remains largely unexplored. Here we study the ID of nonequilibrium growth dynamics data, and show that even after reducing these data to binary form, their binary intrinsic dimension (BID) retains essential physical information. Specifically, we find that, akin to the surface width, it exhibits Family-Vicsek dynamical scaling – a fundamental feature to describe universality in surface roughness phenomena. These findings highlight the ability of the BID to correctly discern key properties and correlations in nonequilibrium data, and open an avenue for alternative characterizations of out-of-equilibrium dynamics.
Statistical Mechanics (cond-mat.stat-mech), Computational Physics (physics.comp-ph), Data Analysis, Statistics and Probability (physics.data-an)
6+5 pages, 5+7 figures
The thermodynamic uncertainty relation of a quantum-mechanically coupled two-qubit system
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-05 20:00 EDT
Kwang Hyun Cho, Hyukjoon Kwon, Changbong Hyeon
The minimal bound of the thermodynamic uncertainty relation (TUR) is modulated from that of the classical counterpart ($ \mathcal{Q}{\rm min}=2$ ) when a quantumness is present in the dynamical process far from equilibrium. A recent study on a dissipative two-level system (TLS) subject to an external field indicates that quantum coherences can suppress the fluctuations of the irreversible current and loosens the TUR bound to $ \mathcal{Q}{\rm min}^{\rm TLS}\approx 1.25$ . Here, we extend on the field-driven single TLS to a quantum-mechanically coupled two-qubit system (TQS), and explore, in addition to the single qubit coherence, how the quantum coupling between the two qubits affects the photon current, fluctuations, and the TUR bound. We find that the TUR bound of TQS depends on the strength of coupling, such that $ \mathcal{Q}{\rm min}^{\rm TQS}=\mathcal{Q}{\rm min}^{\rm TLS}\approx 1.25$ when the two qubits are effectively decoupled under weak coupling, whereas another loose bound $ \mathcal{Q}_{\rm min}^{\rm TQS}\approx 1.36$ is identified for two strongly coupled qubits under strong fields. By contrasting the TQS against two coupled noisy oscillators, we illuminate the quantumness unique to the TQS and its effect on the TUR.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
18 pages, 12 figures
Towards a critical endpoint in the valence fluctuating Eu(Rh${1-x}$Co${x}$)$_2$Si$_2$ system
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-05 20:00 EDT
Franziska Walther, Michelle Ocker, Alexej Kraiker, Nubia Caroca-Canales, Silvia Seiro, Kristin Kliemt, Cornelius Krellner
We report on the successful single crystal growth of pure EuRh$ {_2}$ Si$ {_2}$ and of Eu(Rh$ _{1-x}$ Co$ _{x}$ )$ _2$ Si$ _2$ with $ x\leq0.23$ by the flux method. Through Co substitution, EuRh$ _2$ Si$ _2$ can be tuned from stable antiferromagnetism via a valence-transition state towards the valence-crossover regime. From magnetization measurements, we constructed a $ B - T$ phase diagram for EuRh$ {_2}$ Si$ {_2}$ comprising multiple magnetic phases and showing a sizable magnetic anisotropy within the basal plane of the tetragonal unit cell. This indicates a complex antiferromagnetic ground state for $ x=0$ . By applying positive chemical pressure through the substitution series Eu(Rh$ _{1-x}$ Co$ _{x}$ )$ _2$ Si$ 2$ , a sharp temperature-induced first-order phase transition is observed in magnetization, resistivity and heat capacity for 0.081 $ \leq$ $ x$ $ \leq$ 0.119. The critical end point of this valence transition is located in the phase diagram in the vicinity of 0.119 $ <x{\rm EDX}<$ 0.166. At higher substitution level, the system reaches a valence-crossover regime. The obtained results are presented in a temperature-substitition phase diagram.
Strongly Correlated Electrons (cond-mat.str-el)
Topological pump and its plateau transitions of $N$-leg spin ladder
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-05 20:00 EDT
Kota Yamamoto, Yoshihito Kuno, Tomonari Mizoguchi, Kazuki Sone, Yasuhiro Hatsugai
A topological pump on an $ N\textrm{-}$ leg spin ladder is discussed by introducing spatial clusterization whose adiabatic limit is a set of $ 2N\textrm{-}$ site staircase clusters. We set a pump path in the parameter space that connects two different symmetry protected topological phases. By introducing a symmetry breaking staggered magnetic field, the system is always gapped during the pump. In the topological pump {thus obtained}, the bulk Chern number is given by the number of the critical points enclosed by the pump path. Plateau transitions characterized by the Chern number are demonstrated associated with deformation of the pump path. We find that there are $ N$ critical points enclosed by the pump path for the $ N\textrm{-}$ leg ladder. The ground state phase diagram without symmetry breaking terms is numerically investigated by using the quantized Berry phase. We also discuss the physical picture of edge states in the diagonal boundary, and numerically demonstrate the bulk-edge correspondence for $ N=2,3$ cases.
Statistical Mechanics (cond-mat.stat-mech)
9 pages, 6 figures
Systematic investigation of the generation of luminescent emitters in hBN via irradiation engineering
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-05 20:00 EDT
Pooja C. Sindhuraj, José M. Caridad, Corné Koks, Moritz Fischer, Denys I. Miakota, Juan A. Delgado-Notario, Kenji Watanabe, Takashi Taniguchi, Stela Canulescu, Sanshui Xiao, Martijn Wubs, Nicolas Stenger
Hexagonal boron nitride (hBN), a two-dimensional (2D) material, garners interest for hosting bright quantum emitters at room temperature. A great variety of fabrication processes have been proposed with various yields of quantum emitters. In this work, we study the influence of several parameters, such as irradiation energy, annealing environment, and the type of hBN, on the emitter density in hBN. Our results show (i) high emitter density with oxygen irradiation at 204 eV, (ii) post-annealing in carbon-rich atmospheres significantly increases emitter density, reinforcing carbon’s potential role, (iii) no significant effect of oxygen pre-annealing, and (iv) a slightly increased emitter density from hBN crystals with lower structural quality. Although the precise origin of the emitters remains unclear, our study shows that oxygen irradiation and subsequent inert annealing in a carbon-rich environment play a crucial role in emitter generation, while the other processing parameters have a smaller influence. As such, our systematic study and findings show relevant advances towards the reproducible formation of visible-frequency quantum emitters in hBN.
Materials Science (cond-mat.mtrl-sci), Optics (physics.optics)
13 pages, 8 figures, 5 tables
Multi Moire Networks in Engineered Lateral Hetero-Bilayers: Programmable Phononic Reconfiguration and Second Harmonic Generation
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-05 20:00 EDT
Suman Kumar Chakraborty (1), Frederico B. Sousa (2), Chakradhar Sahoo (3), Indrajeet Dhananjay Prasad (4), Shneha Biswas (5), Purbasha Ray (1), Biswajeet Nayak (1), Rafael Rojas (2), Baisali Kundu (1), Alfred J. H. Jones (3), Jill A. Miwa (3), Søren Ulstrup (3), Sudipta Dutta (5), Santosh Kumar (4), Leandro M. Malard (2), Gopal K. Pradhan (6), Prasana Kumar Sahoo (1) ((1) Quantum Materials and Device Research lab, Materials Science Centre, Indian Institute of Technology Kharagpur, West Bengal, India (2) Departamento de Física, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil (3) Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University, 8000 Aarhus C, Denmark (4) Department of Physics, Indian Institute of Technology Goa, Goa, India (5) Department of Physics, Indian Institute of Science Education and Research Tirupati, Andhra Pradesh, India (6) Department of Physics, School of Applied Sciences, KIIT Deemed to be University, Bhubaneswar, India)
Moire engineering in two-dimensional transition metal dichalcogenides enables access to correlated quantum phenomena. Realizing such effects demands simultaneous control over twist angle and material composition to modulate phonons, excitons, and their interactions. However, most studies rely on exfoliated flakes, limiting scalability and systematic exploration. Here, we demonstrate a scalable multi-moire network by vertically stacking CVD-grown monolayer lateral heterostructures. Signatures of moire non-rigidity, including phonon frequency softening, linewidth broadening, and strain localization, are attributed to two lattice relaxation modes; rotational reconstruction and volumetric dilation. Micro-angle-resolved photoemission spectroscopy reveals that interfacial orbital interactions modulate interlayer coupling. At aligned angles, molybdenum diselenides exhibit reduced valley polarization and Davydov splitting, indicating strain-induced symmetry breaking and chiral phonon effects. Notably, SHG modulation was obderved with variation in twist angle due to lower coherence and band-offset-driven phase delay. First-principles calculations support these findings. This work provides a route to programmable, scalable multi-moire platforms for opto-straintronics, quantum sensing, and on-chip photonics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Non-universal Impact of Cholesterol on Ionic Liquid-Membrane Interactions
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-05 20:00 EDT
J. Gupta, V. K. Sharma, P. Hitaishi, A. K. Jha, J. B. Mitra, H. Srinivasan, S. Kumar, A. Kumar, S. K. Ghosh, S. Mitra
Understanding the role of cholesterol in ionic liquid (IL)-membrane interactions is essential for advancing biomedical applications of ILs, including the development of innovative antimicrobial agents. In this study, we explore the intricate and multifaceted role of cholesterol in modulating IL-membrane interactions, employing a comprehensive suite of biophysical techniques. We systematically examine how IL alkyl chain length and membrane physical state influence the impact of cholesterol on IL-lipid membrane interaction. The incorporation of ILs is shown to increase the area per lipid in both pristine dipalmitoylphosphatidylcholine (DPPC) and DPPC-cholesterol membranes. Cholesterol modulates the impact of ILs on lipid conformation, membrane viscoelasticity, and phase behavior. Small-angle neutron scattering and dynamic light scattering measurements reveal that cholesterol mitigates IL-induced structural perturbations in vesicles. Our isothermal titration calorimetry measurements reveal that the presence of cholesterol significantly weakens the binding of ILs to membranes. Intriguingly, despite this reduced binding affinity, cholesterol-containing membranes demonstrate enhanced permeabilization. This counterintuitive effect is attributed to cholesterol’s ordering of lipid membranes, which increases susceptibility to stress and defects. Our results underscore the complex and non-universal interplay between lipid composition, IL alkyl chain length, and membrane phase state. These insights provide a deeper understanding of cholesterol’s role in IL-membrane interactions, paving the way for the design of advanced applications of ILs in antimicrobial therapy and drug delivery.
Soft Condensed Matter (cond-mat.soft)
Direct Evidence of Metal-Ligand Redox in Li-ion Battery Cathodes
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-05 20:00 EDT
Galo J. Paez Fajardo, Daniela Dogaru, Muhammad Ans, Matthew J. W. Ogley, Veronika Majherova, Innes McClelland, Shohei Hayashida, Pascal Puphal, Masahiko Isobe, Bernhard Keimer, Pardeep K. Thakur, Tien-Lin Lee, Dave C. Grinter, Pilar Ferrer, Serena A. Cussen, Matthias Hepting, Louis F. J. Piper
Describing Li-ion battery cathodes in terms of distinct transition metal or oxygen redox regimes can lead to confusion in understanding metal-ligand hybridisation, oxygen dimerisation, and degradation. There is a pressing need to study the electronic structure of these materials and determine the role each cation and anion plays in charge compensation. Here, we employ transition metal Ledge X-ray Resonance Photoemission Spectroscopy in conjunction with Single Impurity Anderson simulations to directly evaluate the redox mechanisms in (de-)lithiated battery electrodes. This approach reconciles the redox description of two canonical cathodes – LiMn$ _{0.6}$ Fe$ _{0.4}$ PO$ _{4}$ and LiNiO$ _{2}$ – in terms of varying degrees of charge transfer using the established Zaanen-Sawatzky-Allen framework, common to condensed matter physics. In LiMn$ _{0.6}$ Fe$ _{0.4}$ PO$ _{4}$ , we show that capacity arises due to the depopulation of metal 3d states. Whereas, in LiNiO$ _{2}$ , charge transfer dominates and redox occurs through the formation and elimination of ligand hole states. This work clarifies the role of oxygen in Ni-rich system and provides a framework to explain how capacity can be extracted from oxygen-dominated states in highly covalent systems without needing to invoke dimerisation.
Materials Science (cond-mat.mtrl-sci)
Intrinsic magnetic topological insulators of the MnBi${}_2$Te${}_4$ family
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-05 20:00 EDT
A. Yu. Vyazovskaya, M. Bosnar, E. V. Chulkov, M. M. Otrokov
This short review appears on the occasion of the fifth anniversary of discovery of intrinsic magnetic topological insulators (MTIs) of the MnBi$ {}_2$ Te$ {}_4$ family, which have attracted a great deal of attention recently. This family of materials has been discovered in attempts to increase the observation temperature of the quantum anomalous Hall effect as well as to facilitate the eventual realization of the topological magnetoelectric effect. Therefore, we first briefly introduce these effects, then describe the experimental state-of-the-art in the MTIs field just prior to MnBi$ {}_2$ Te$ {}_4$ appearance, after which we discuss the basic properties of this material and its family. Finally, we overview the exciting progress made during five years of intense research in this field.
Materials Science (cond-mat.mtrl-sci)
33 pages, 3 figures
Commun Mater 6, 88 (2025)
DFT based comparative study of the physical properties of MAlB (M = V, Ta, Mo, Nb) MAB compounds
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-05 20:00 EDT
Jahid Hassan, M. A. Masum, Ruman Ali, Md. Enamul Haque, S. H. Naqib
MAB phases have appealing physical features that make them appropriate for a wide range of applications. Motivated by this, we present density functional theory (DFT) calculations of the structural, elastic, bonding, electronic band dispersion, acoustic behavior, phonon spectrum, various thermomechanical and optoelectronic properties of VAlB and TaAlB ternary borides for the first time. The computed ground state lattice parameters of both compounds are very consistent with experimental data. The formation enthalpy, elastic constants, and phonon dispersion calculations indicate that both compounds are chemically, mechanically, and dynamically stable, respectively. The physical parameters of VAlB and TaAlB are studied and compared with those of MoAlB and NbAlB MAB compounds.
Materials Science (cond-mat.mtrl-sci)
Specular-Andreev reflection and Andreev interference in an Ising superconductor junction
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-05 20:00 EDT
Gaoyang Li, Sourabh Patil, Yanxia Xing, Wolfgang Belzig, Gaomin Tang
Being resilient to magnetic field, Ising superconductor serves as an exceptional platform for studying the interplay between superconductivity and magnetism. In this Letter, we first explore the transport properties of a two-terminal graphene-Ising superconductor junction where mirage gaps are induced in the superconductor by an exchange field due to magnetic proximity effect. We demonstrate that the chemical potential range of graphene supporting specular-Andreev reflection at the interface is between the two mirage gaps and about twice the Ising spin-orbit coupling strength. This enhances the resilience of observing specular-Andreev reflection against graphene potential fluctuations in experiments. We further study the Andreev interference effect based on a four-terminal junction of which two terminals consist of Ising superconductors in the presence of exchange fields. Due to the finite contribution from the spin-triplet pairing, the interference can be modulated by tuning the relative orientation of the exchange fields in addition to the traditional scheme by changing superconducting phase difference and the chemical potential of the normal region.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
6 pages, 4 figures
Direct evidence for two-gap superconductivity in hydrogen-intercalated titanium diselenide
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-05 20:00 EDT
Erik Piatti, Gaia Gavello, Giovanni A. Ummarino, Filip Košuth, Pavol Szabó, Peter Samuely, Renato S. Gonnelli, Dario Daghero
Transition-metal dichalcogenides (TMDs) offer an extremely rich material platform in the exploration of unconventional superconductivity. The unconventional aspects include exotic coupling mechanisms such as the Ising pairing, a complex interplay with other electronic orders such as charge-density waves (CDWs), symmetry-breaking and topological effects, and non-trivial gap structures such as multi-gap and possible nodal phases. Among TMDs, titanium diselenide (1$ T$ -TiSe$ _2$ ) is one of the most studied and debated cases. Hints to an anomalous structure of its superconducting order parameter have emerged over the years, possibly linked to its spatial texturing in real and reciprocal space due to the presence of a 2$ \times$ 2$ \times$ 2 CDW phase, or to a pressure-driven multi-band Fermi surface. However, a direct evidence for a non-trivial structure of the superconducting gap in this material is still lacking. In this work, we bring the first evidence for a two-gap structure in the recently-discovered H-intercalated TiSe$ _2$ superconductor (with T$ _c \simeq 3.6$ K) by an extensive experimental study that combines magnetotransport measurements, point-contact spectroscopy and scanning tunnel spectroscopy. We show that the temperature dependence of the upper critical field (for $ \vec B \parallel c$ ) as well as the shape of the point-contact and tunneling spectra strongly suggest the existence of two distinct superconducting gaps, and can indeed all be fitted in a self-consistent way with the same gap amplitudes $ \Delta_1 = 0.26 \pm 0.12$ meV and $ \Delta_2 =0.62 \pm 0.18$ meV.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
24 pages, 11 figures; comments are welcome
Tunable resonant Raman scattering with temperature in vertically aligned 2H-SnS2
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-05 20:00 EDT
Atul G. Chakkar, Deepu Kumar, Ashok Kumar, Mahesh Kumar, Pradeep Kumar
Two-dimensional semiconducting materials have a wide range of applications in various fields due to their excellent properties and rich physics. Here, we report a detailed investigation of the temperature dependent Raman and Photoluminescence measurements on the vertically aligned 2H-SnS2 grown by CVD method. Our results established the tunability of the resonant Raman scattering with varying temperature, i.e. a crossover between resonance and non-resonance conditions for the current system. We also discussed the temperature as well as laser power dependence of the low frequency asymmetric Raman mode which is interlayer shear mode. Temperature dependence of the intensity of the phonon modes also manifests the tunability of the resonant Raman scattering with temperature. Our temperature dependent Photoluminescence measurement shows the strong temperature dependence of the excitonic peaks which is confirmed with laser power dependence of the Photoluminescence measurement at room temperature. Our investigation may help to design and fabricate devices based on vertically aligned 2H-SnS2 and other similar materials in future.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Phase-field modeling of elastic microphase separation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-05 20:00 EDT
Hamza Oudich, Pietro Carrara, Laura De Lorenzis
We propose a novel phase-field model to predict elastic microphase separation in polymer gels. To this end, we extend the Cahn-Hilliard free-energy functional to incorporate an elastic strain energy and a coupling term. These contributions are naturally obtained from a derivation that starts from an entropic elastic energy density combined with the assumption of weak compressibility, upon second-order approximation around the swollen state. The resulting terms correspond to those of a poroelastic formulation where the coupling energetic term can be interpreted as the osmotic work of the solvent within the polymer matrix. Additionally, a convolution term is included in the total energy to model non-local forces responsible for coarsening arrest. With analytical derivations in 1D and finite element computations in 2D we show that the mechanical deformation controls the composition of the stable phases, the initial characteristic length and time, the coarsening rates and the arrested characteristic length. Moreover, we demonstrate that the proposed coupling is able to predict the arrest of coarsening at a length scale controlled by the stiffness of the dry polymer. The numerical results show excellent agreement with the experimental evidence in terms of phase-separated morphology and scaling of the characteristic length with the stiffness of the dry polymer.
Materials Science (cond-mat.mtrl-sci)
Accelerating point defect photo-emission calculations with machine learning interatomic potentials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-05 20:00 EDT
Kartikeya Sharma, Antoine Loew, Haiyuan Wang, Fredrik A. Nilsson, Miguel A. L. Marques, Kristian S. Thygesen
We introduce a computational framework leveraging universal machine learning interatomic potentials (MLIPs) to dramatically accelerate the calculation of photoluminescence (PL) spectra of atomic or molecular emitters with \emph{ab initio} accuracy. By replacing the costly density functional theory (DFT) computation of phonon modes with much faster MLIP phonon mode calculations, our approach achieves speed improvements exceeding an order of magnitude with minimal precision loss. We benchmark the approach using a dataset comprising \emph{ab initio} emission spectra of 791 color centers spanning various types of crystal point defects in different charge and magnetic states. The method is also applied to a molecular emitter adsorbed on a hexagonal boron nitride surface. Across all the systems, we find excellent agreement for both the Huang-Rhys factor and the PL lineshapes. This application of universal MLIPs bridges the gap between computational efficiency and spectroscopic fidelity, opening pathways to high-throughput screening of defect-engineered materials. Our work not only demonstrates accelerated calculation of PL spectra with DFT accuracy, but also makes such calculations tractable for more complex materials.
Materials Science (cond-mat.mtrl-sci), Atomic Physics (physics.atom-ph), Computational Physics (physics.comp-ph)
9 pages, 5 figures, 1 table
Quasiparticle Interference of Spin-Triplet Superconductors: Application to UTe$_2$
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-05 20:00 EDT
Hans Christiansen, Brian M. Andersen, P. J. Hirschfeld, Andreas Kreisel
Quasiparticle interference (QPI) obtained from scanning tunneling microscopy (STM) is a powerful method to help extract the pairing symmetry of unconventional superconductors. We examine the general properties of QPI on surfaces of spin-triplet superconductors, where the properties of the $ \vec d$ -vector order parameter and topological surface bound states offer important differences from QPI on spin-singlet superconducting materials. We then apply the theory to a model specific to UTe$ 2$ , and compare the resulting QPI with recent STM measurements. We conclude that the two candidate Cooper pair instabilities $ B{2u}$ and $ B_{3u}$ exhibit distinct features in the QPI intensity to discriminate these using the experimental data. Characteristic features of the emergent topological surface states protected by mirror symmetries provide further unique signatures to help pinpointing the pairing symmetry channel of UTe$ _2$ .
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
7 pages. 3 figures