CMP Journal 2025-09-15
Statistics
Nature: 1
Nature Materials: 3
Nature Physics: 1
Physical Review Letters: 1
arXiv: 45
Nature
Continuous operation of a coherent 3,000-qubit system
Original Paper | Atomic and molecular physics | 2025-09-14 20:00 EDT
Neng-Chun Chiu, Elias C. Trapp, Jinen Guo, Mohamed H. Abobeih, Luke M. Stewart, Simon Hollerith, Pavel L. Stroganov, Marcin Kalinowski, Alexandra A. Geim, Simon J. Evered, Sophie H. Li, Xingjian Lyu, Lisa M. Peters, Dolev Bluvstein, Tout T. Wang, Markus Greiner, Vladan Vuletić, Mikhail D. Lukin
Neutral atoms are a promising platform for quantum science, enabling advances in areas ranging from quantum simulations1-3 and computation4-10 to metrology, atomic clocks11-13 and quantum networking14-16. While atom losses typically limit these systems to a pulsed mode, continuous operation17-22 could significantly enhance cycle rates, remove bottlenecks in metrology23, and enable deep-circuit quantum evolution through quantum error correction24,25. Here we demonstrate an experimental architecture for high-rate reloading and continuous operation of a large-scale atom array system while realizing coherent storage and manipulation of quantum information. Our approach utilizes a series of two optical lattice conveyor belts to transport atom reservoirs into the science region, where atoms are repeatedly extracted into optical tweezers without affecting the coherence of qubits stored nearby. Using a reloading rate of 300,000 atoms in tweezers per second, we create over 30,000 initialized qubits per second, which we leverage to assemble and maintain an array of over 3,000 atoms for more than two hours. Furthermore, we demonstrate persistent refilling of the array with atomic qubits in either a spin-polarized or a coherent superposition state while preserving the quantum state of stored qubits. Our results pave the way for realization of large-scale continuously operated atomic clocks, sensors, and fault-tolerant quantum computers.
Atomic and molecular physics, Quantum information, Qubits
Nature Materials
Streaming flexoelectricity in saline ice
Original Paper | Fluidics | 2025-09-14 20:00 EDT
X. Wen, Q. Ma, J. Liu, U. Saeed, S. Shen, G. Catalan
Despite 10% of the Earth’s surface being covered by ice, ice power remains untapped. Although ice is known to generate electricity upon bending via flexoelectricity1, the generated electric polarization per curvature, that is, the flexoelectric coefficient, is too small (~1-10 nC m-1) to be utilized for electromechanical devices. Here we demonstrate that doping ice with NaCl can enhance its flexoelectric coefficient 1,000-fold, to ~1-10 μC m-1. We find that this enhancement is due to the bending-induced streaming current along ice grain boundaries. On the basis of this mechanism, we fabricated flexural devices with an effective piezoelectric coefficient of ~4,000 pC N-1, which is comparable to that of the best piezoelectric materials. The high flexoelectricity of saline ice brings the vision of harnessing ice power one step closer to reality, and may also be relevant to the electrical activity of ice-covered terrestrial regions and icy ocean worlds such as Europa or Enceladus. In addition, the model for coupling between strain gradients and streaming currents is not limited to ice and provides a general framework for extracting electromechanical activity from liquid-infused porous solids.
Fluidics, Materials for energy and catalysis, Sensors and biosensors, Structure of solids and liquids, Surfaces, interfaces and thin films
Interstitial oxygen order and its competition with superconductivity in La2PrNi2O7+δ
Original Paper | Structure of solids and liquids | 2025-09-14 20:00 EDT
Zehao Dong, Gang Wang, Ningning Wang, Wen-Han Dong, Lin Gu, Yong Xu, Jinguang Cheng, Zhen Chen, Yayu Wang
High-temperature superconductivity in pressurized La3Ni2O7 has attracted considerable interest, yet the superconducting phase is rather fragile. Although bulk superconductivity can be achieved by Pr substitution for La, the underlying mechanism is still unclear. A further puzzle is the role of oxygen content: moderate oxygenation enhances superconductivity, whereas high-pressure oxygen annealing suppresses it. Here combining multislice electron ptychography and electron energy-loss spectroscopy, we show that Pr doping mitigates oxygen vacancies and stabilizes a near-stoichiometric La2PrNi2O7 structure. Strikingly, high-pressure oxygen annealing introduces interstitial oxygen atoms that arrange into a stripe-ordered superstructure, which generates excess hole carriers and alters the electronic structure, ultimately suppressing superconductivity under pressure. This contrasts sharply with cuprates, where similar oxygen ordering is known to induce superconductivity. Our findings reveal a competition between interstitial oxygen ordering and superconductivity in bilayer nickelates, providing key insights into the pairing mechanism and guiding principles for engineering more robust superconducting phases.
Structure of solids and liquids, Superconducting properties and materials
Ultraconfined terahertz phonon polaritons in hafnium dichalcogenides
Original Paper | Nanophotonics and plasmonics | 2025-09-14 20:00 EDT
Ryan A. Kowalski, Niclas S. Mueller, Gonzalo Álvarez-Pérez, Maximilian Obst, Katja Diaz-Granados, Giulia Carini, Aditha Senarath, Saurabh Dixit, Richarda Niemann, Raghunandan B. Iyer, Felix G. Kaps, Jakob Wetzel, J. Michael Klopf, Ivan I. Kravchenko, Martin Wolf, Thomas G. Folland, Lukas M. Eng, Susanne C. Kehr, Pablo Alonso-Gonzalez, Alexander Paarmann, Joshua D. Caldwell
The confinement of electromagnetic radiation to subwavelength scales relies on strong light-matter interactions. In the infrared and terahertz spectral ranges, phonon polaritons are commonly employed to achieve deeply subdiffractional light confinement, with such optical modes offering much lower losses in comparison to plasmon polaritons. Among these, hyperbolic phonon polaritons in anisotropic materials offer a promising platform for light confinement. Here we report on ultraconfined phonon polaritons in hafnium-based dichalcogenides with confinement factors exceeding λ0/250 in the terahertz spectral range. This extreme light compression within deeply subwavelength thin films is enabled by the large magnitude of the light-matter coupling strength in these compounds and the natural hyperbolicity of HfSe2. Our findings emphasize the role of light-matter coupling for polariton confinement, which for phonon polaritons in polar dielectrics is dictated by the transverse-longitudinal optical phonon energy splitting. Our results demonstrate transition-metal dichalcogenides as an enabling platform for terahertz nanophotonic applications.
Nanophotonics and plasmonics, Polaritons, Terahertz optics, Two-dimensional materials
Nature Physics
Decoding frequency-modulated signals increases information entropy in bacterial second messenger networks
Original Paper | Biological physics | 2025-09-14 20:00 EDT
Rongrong Zhang, Shengjie Wan, Jiarui Xiong, Lei Ni, Ye Li, Yajia Huang, Bing Li, Mei Li, Shuai Yang, Fan Jin
Bacterial second messenger networks transmit environmental information through both amplitude and frequency modulation strategies. However, the mechanisms by which cells decode frequency-encoded signals remain poorly understood. By reconstructing the cyclic adenosine monophosphate second messenger system in Pseudomonas aeruginosa, we demonstrate that frequency-to-amplitude signal conversion emerges through three distinct filtering modules that decode frequency-encoded signals into gene expression patterns. Our mathematical framework predicts a range of frequency filtering regimes controlled by a dimensionless threshold parameter. We validated these using synthetic circuits and an automated experimental platform. Quantitative analysis reveals that under the given parameter conditions, frequency modulation expands the accessible state space more substantially than amplitude modulation alone. The total number of accessible states scales as the square of the number of regulated genes for frequency-enhanced control, compared with the power of 0.8 for amplitude-only control. This results in approximately two additional bits of information entropy in three-gene systems when using frequency-based control. Our findings establish the fundamental principles of frequency-based signal processing in bacterial second messenger networks, revealing how cells exploit temporal dynamics to regulate multiple genes and expand accessible state spaces. This provides insights into both cellular information physics and design principles for synthetic biology.
Biological physics, Biophysics
Physical Review Letters
Inclusive Semileptonic Decays of the ${D}_{s}$ Meson: Lattice QCD Confronts Experiments
Article | Particles and Fields | 2025-09-15 06:00 EDT
Alessandro De Santis, Antonio Evangelista, Roberto Frezzotti, Giuseppe Gagliardi, Paolo Gambino, Marco Garofalo, Christiane Franziska Groß, Bartosz Kostrzewa, Vittorio Lubicz, Francesca Margari, Marco Panero, Francesco Sanfilippo, Silvano Simula, Antonio Smecca, Nazario Tantalo, and Carsten Urbach
Standard model prediction for the semileptonic decay of meson using state-of-the-art lattice QCD calculation agrees well with the experimental determinations.
Phys. Rev. Lett. 135, 121901 (2025)
Particles and Fields
arXiv
Nonequilibrium nonlinear response theory of amplitude-dependent dissipative conductivity in disordered superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-15 20:00 EDT
This work investigates amplitude-dependent nonlinear corrections to the dissipative conductivity in superconductors, using the Keldysh-Usadel theory of nonequilibrium superconductivity, which captures the nonequilibrium dynamics of both quasiparticles and the pair potential. Our rigorous formulation naturally incorporates both the direct nonlinear action of the photon field and indirect contributions mediated by nonequilibrium variations in the pair potential, namely the Eliashberg effect and the Higgs mode. The third-harmonic current, often regarded as a hallmark of the Higgs mode, arises from both the direct photon action and the Higgs mode. Our numerical results are in excellent agreement with previous studies. In contrast, the first-harmonic current, and consequently the dissipative conductivity, receives contributions from all three mechanisms: the direct photon action, the Higgs mode, and the Eliashberg effect. It is shown that that the nonlinear correction to dissipative conductivity can serve as a fingerprint of the Higgs mode, appearing as a resonance peak at a frequency near the superconducting gap ( \Delta ). In addition, our results provide microscopic insight into amplitude-dependent dissipation at frequencies well below ( \Delta ), which is particularly relevant for applied superconducting devices. In particular, the long-standing issue concerning the frequency dependence of the amplitude-dependent quality factor is explained as originating from the direct nonlinear action of the photon field, rather than from contributions by the Higgs mode and the Eliashberg effect. Our practical and explicit expression for the nonlinear conductivity formula makes our results accessible to a broad range of researchers.
Superconductivity (cond-mat.supr-con), Accelerator Physics (physics.acc-ph), Instrumentation and Detectors (physics.ins-det), Quantum Physics (quant-ph)
18 pages, 8 figures. This is the initial version submitted to a journal
Pseudogap-induced change in the nature of the Lifshitz transition in the two-dimensional Hubbard model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-15 20:00 EDT
Maria C. O. Aguiar, Helena Bragança, Indranil Paul, Marcello Civelli
We study the behavior of the density of states and the $ B_{1g}$ nematic susceptibility extracted from Raman response data across the doping-driven Lifshitz transition comparing the weak and strong interaction cases. Our results were obtained using cluster dynamical mean field theory for the two-dimensional Hubbard model. In the weakly correlated Fermi liquid regime, both quantities are approximately symmetric around the Lifshitz transition doping $ p_{LT}$ . In the strongly correlated regime, the low-doping pseudogap leads to an asymmetric, discontinuous evolution when the Fermi surface changes from hole-like to electron-like at $ p_{LT}$ . The Lifshitz transition thus changes character because it is tied to the pseudogap-Fermi-liquid transition. These results are consistent with available observations and should foster further experimental investigations.
Strongly Correlated Electrons (cond-mat.str-el)
9 pages, 7 figures
CaCd$_2$P$_2$: A Visible-Light Absorbing Zintl Phosphide Stable under Photoelectrochemical Water Oxidation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-15 20:00 EDT
Guillermo L. Esparza, Zhenkun Yuan, Muhammad Rubaiat Hasan, Yagmur Coban, Gideon Kassa, Vivek Shastry Devalla, Tejas Nivarty, Jack R. Palmer, Jifeng Liu, Kirill Kovnir, Geoffroy Hautier, David P Fenning
A key bottleneck to solar fuels is the absence of stable and strongly absorbing photoelectrode materials for the oxygen evolution reaction (OER). Modern approaches generally trade off between stable but weakly absorbing materials, such as wide bandgap oxides, or strongly absorbing materials that rely on encapsulation for stability and are weakly catalytic, such as the III-V family of semiconductors. Of interest are materials like transition metal phosphides, such as FeP$ _2$ , that are known to undergo beneficial in situ surface transformations in the oxidative environment of OER, though stability has remained a primary hurdle. Here we report on CaCd$ _2$ P$ _2$ , a Zintl phase visible-light absorber with favorable 1.6 eV bandgap, that we identified using high-throughput computational screening. Using a combination of photoelectrochemical measurements, microscopy, and spectroscopy, we show that CaCd$ _2$ P$ _2$ undergoes a light-stabilized surface transformation that renders it stable under alkaline OER conditions. We also show that the well known OER catalyst CoPi can act as a stable co-catalyst in synergy with the \textit{in-situ} CaCd$ _2$ P$ _2$ surface. The light-induced stabilization that CaCd$ _2$ P$ _2$ displays is in sharp contrast to the photocorrosion commonly observed in visible light-absorbing photoelectrodes. The broader AM$ _2$ P$ _2$ family of Zintl phases offers a significant opportunity to explore stabilizing interface chemistry and re-design the manner in which low-bandgap semiconductors are used for photoelectrochemical energy conversion.
Materials Science (cond-mat.mtrl-sci)
Pressure tuning of putative quantum criticality on YbV6Sn6
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-15 20:00 EDT
P. C. Sabino, L. Mendonça-Ferreira, J. G. Dias, G. G. Vasques, M. Dutra, H. Pizzi, P. G. Pagliuso, M. A. Avila
YbV$ _6$ Sn$ _6$ is a recently discovered heavy-fermion compound that orders at T$ _N\approx 0.4$ K and exhibits a magnetic field-tuned quantum critical point at $ H \approx 10$ kOe. In this work, we have grown YbV$ _6$ Sn$ _6$ single crystals by the self-flux method, to investigate their physical properties at ambient pressure and their electrical transport properties under hydrostatic pressure. At higher temperatures, we observed a decrease in the Kondo temperature, accompanied by the appearance of a local minimum followed by a local maximum, associated with the onset of the coherent Kondo regime. Power law fitting at low temperatures indicated a recovery of the Fermi-liquid regime for pressures below 1 GPa. Above 1 GPa, a reentrance of non-Fermi-liquid behavior is suggested by a decrease in the exponent $ n$ , accompanied by a substantial increase in the parameter $ A$ , indicating the approach of a new quantum criticality tuned by hydrostatic pressure. The broad range of interactions present in YbV$ _6$ Sn$ _6$ , including RKKY, crystalline electric field (CEF), and Kondo lattice effects, appears to lead to a complex phase diagram. We present a putative phase diagram featuring double quantum criticality tuned by both magnetic field and hydrostatic pressure.
Strongly Correlated Electrons (cond-mat.str-el)
Dimensionality reduction of optically generated vortex strings in a charge density wave
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-15 20:00 EDT
Sajal Dahal, Alex H. Miller, Viktor Krapivin, Gal Orenstein, Ryan A. Duncan, Nicholas Leonard, Matthew J. Hurley, Jade Stanton, Roman Mankowsky, Henrik Lemke, Anisha Singh, Ian Fisher, Mariano Trigo, Samuel W. Teitelbaum
In phase transitions, mesoscale structures such as topological defects, vortex strings, and domain walls control the path towards equilibrium, and thus the functional properties of many active devices. In photoinduced phase transitions driven by femtosecond laser excitation, the temporal (pulse duration) and spatial (penetration depth) structure of the optical excitation present opportunities for control and creating structures with unique topologies. By performing time-resolved optical pump, x-ray probe experiments on the CDW system Pd-intercalated ErTe$ _{3}$ , we gain access to the nanoscale dynamics of the mesoscale topological features (vortex strings) produced after a quench, which have a different apparent dimensionality than the topological defects predicted from the bulk system. We show that these vortex strings persist for much longer than the electronic recovery time. The critical exponent obtained from power-law scaling of the intensity as a function of wavevector shows a reduction in the effective dimensionality of the topological defects in the system, corroborated by time-dependent Ginzburg-Landau simulations. Our results demonstrate a novel pathway to use light to control the dimensionality and orientation of topological defects in quantum materials, which could be used to stabilize competing quantum states.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Statistical Mechanics (cond-mat.stat-mech), Strongly Correlated Electrons (cond-mat.str-el)
7 pages, 3 figures. Supplemental AVI movies included
Surface Topological Quantum Criticality II: Conformal manifolds, Isolated fixed points and Entanglement
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-15 20:00 EDT
In this article, we propose the realization of conformal manifolds, which are smooth manifolds of scale-conformal invariant interacting Hamiltonians in two-dimensional quantum many-body systems. Such phenomena can occur in various interacting systems, including topological surfaces or 2D bulks. Building on previous observations, we demonstrate that a conformal manifold can emerge as an exact solution when the number of fermion colors, (N_c), becomes infinite. We identify distinct exact marginal deformation operators uniquely associated with the conformal manifolds. By considering (N_c) as finite but large, we show that quantum fluctuations induce a fermion field renormalization that results in mildly infrared relevant or irrelevant renormalization-group (RG) flow within a conformal manifold, producing standard isolated infrared stable Wilson-Fisher fixed points. These can be grouped with ultraviolet stable fixed points into a discrete manifold due to the spontaneous symmetry breaking of an emergent (SO(\mathcal{N})) dynamical symmetry in the RG flow as (N_c \rightarrow \infty). Additionally, we find a correlation between the direction of the RG flow within the manifold and an increase in EPR-like entanglement entropy. The infrared-stable Wilson-Fisher fixed points, induced by quantum fluctuations, are linked to theories on the conformal manifold where interaction operators are maximally entangled in flavor space. Our studies provide an effective framework for addressing topological quantum critical points with high-dimensional interaction parameter spaces, potentially housing many fixed points of various stabilities. They also highlight the central role of entangled conformal operators and their entropy in shaping universality classes of surface topological quantum phase transitions. We conclude with open questions and possible future directions.
Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Theory (hep-th)
22 pages, 6 figures, 4 tables. Comments and suggestions are most welcome, email ID-saran@phas.this http URL
Fractal growth of higher-order topological insulators
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-15 20:00 EDT
Yutaro Tanaka, Shuai Zhang, Tiantian Zhang, Shuichi Murakami
Understanding crystal growth and morphology is a fundamental issue in condensed matter physics. In this work, we reveal the fractal morphology of growing crystals of higher-order topological insulators and show that the corners of the crystals grow preferentially compared to the edges in the presence of the corner states. We further demonstrate that when we compare the crystal shape of the higher-order topological insulator with that of the trivial insulator with the same value of the fractal dimension $ D_f$ , the former has a smaller value of the fractal dimension of coastlines $ D_{f,c}$ than the latter. This indicates that, for crystals with a similar degree of corner development, those in the higher-order topological phase have smoother edges. Because the relationship between the area and the perimeter of the crystals is governed by the ratio of these fractal dimensions, the higher-order topological insulator and the trivial insulator exhibit distinct perimeter-area relationships.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
9+7 pages, 6+2 figures
Magnonic Combinatorial Memory for High-density Data Storage
New Submission | Other Condensed Matter (cond-mat.other) | 2025-09-15 20:00 EDT
Mykhaylo Balinskiy, Paulo Julio, Jeffrey Vargas, Diana Balaguer, Alexander Khitun
There is an urgent need to enhance the storage density of memory devices to accommodate the exponentially increasing amount of data generated by humankind. In this work, we describe Magnonic Combinatorial Memory (MCM), where the bits of information are stored in the signal propagation paths in the network. The number of paths among the elements of the network is much larger compared to the number of elements, which makes it possible to enhance the data storage density compared to conventional memory devices. MCM is an active ring circuit consisting of electric and magnonic parts. The electric part includes a broadband amplifier, phase shifters, and frequency filters. The magnonic part is a mesh of frequency-dependent elements. Signal propagation path(s) in the mesh depend on the amplitude/phase matching between the electric and magnetic parts. The operation of the MCM is described based on the network model, where information is encoded in the S-parameters of the network elements as well as in the element arrangement in the network. We present experimental data for MCM with a four-terminal magnonic element. The element consists of a single-crystal yttrium iron garnet Y3Fe2(FeO4)3 (YIG) film and magnets on top of the film. There are four micro antennas aimed to convert electromagnetic waves into spin waves and vice versa. One of the antennas is used as an input port while the other three are the output ports. Experimental data show the prominent dependence of the element S-parameters on the magnet arrangement. The number of possible arrangements scales factorially with the number of magnets. There is a number of bits that can be encoded into one magnet arrangement. The results demonstrate a robust operation of MCM with an On/Off ratio for path detection exceeding 50 dB at room temperature. Physical limits and practical constraints of MCM are also discussed.
Other Condensed Matter (cond-mat.other), Applied Physics (physics.app-ph)
Hard and soft phase slips in a Fabry-Pérot quantum Hall interferometer
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-15 20:00 EDT
N. L. Samuelson, L. A. Cohen, W. Wang, S. Blanch, T. Taniguchi, K. Watanabe, M. P. Zaletel, A. F. Young
Quantum Hall Fabry-Pérot interferometers are sensitive to the properties of bulk quasiparticles enclosed by the interferometer loop, with the interference phase containing information about both the quasiparticle statistics and the Coulomb-mediated bulk-edge coupling. Previous studies have explored the role of the bulk-edge coupling in an equilibrium picture where quasiparticles enter and exit the interferometer rapidly compared to the timescale over which the interferometer phase is measured. Here, we present data from a monolayer graphene quantum Hall interferometer in the integer quantum Hall regime at $ \nu = -1$ and $ \nu = -2$ . Quantum interference shows phase slips associated with the entrance of quasiparticles to the interferometer bulk. Tracing the dependence of these phase slips on the magnetic field, we show that the equilibration time can become as long as several minutes. We further use our multi-gated geometry to identify two classes of phase slips. The first is associated with the addition of a quasiparticle to a bulk `puddle’ of quasiparticles uniformly coupled to the entire chiral edge state, while the second is associated with the addition of a quasiparticle trapped by a defect site that couples predominantly to the closest portion of the edge.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Main Text: 6 pages, 4 figures Supplement: 6 pages, 3 figures
Evolution from Topological Dirac Metal to Flat-band-Induced Antiferromagnet in Layered KxNi4S2 (0<=x<=1)
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-15 20:00 EDT
Hengdi Zhao, Xiuquan Zhou, Hyowon Park, Tianqi Deng, Brandon Wilfong, Alann P. Au II, Samuel E. Pate, Craig M. Brown, Hui Wu, Tushar Bhowmick, Tessa McNamee, Ravhi Kumar, Yu-Sheng Chen, Zhi-Li Xiao, Russell Hemley, Weizhao Cai, Shanti Deemyad, Duck-Young Chung, Stephan Rosenkranz, Mercouri G. Kanatzidis
Condensed matter systems with coexisting Dirac cones and flat bands, and a switchable control between them within a single system, are desirable but remarkably uncommon. Here we report a layered quantum material system, KxNi4S2 (0 <= x <= 1), that simultaneously hosts both characteristics without involving typical Kagome/honeycomb lattices. Enabled by a topochemical K-deintercalation process, the Fermi surface can be fine-tuned continuously over a wide range of energies. Consequently, a non-magnetic Dirac-metal state with a topological nontrivial Z2 index of 1;(000), supported by first-principles calculations and high mobility up to 1471 cm2V-1s-1, is observed on the K-rich x = 1 side, whereas a flat-band induced antiferromagnetic state with TN up to 10.1 K emerges as K-content approaches 0. The KxNi4S2 system offers a versatile platform for exploring emerging phenomena and underscores a viable pathway for in-situ control of quantum materials dominated by Dirac cones, flat bands, and their interplay.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
TbPt6Al3: A rare-earth-based g-wave altermagnet with a honeycomb structure
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-15 20:00 EDT
R. Oishi, T. Taniguchi, D. T. Adroja, M. D. Le, M. Aouane, T. Onimaru, K. Umeo, I. Ishii, T. Takabatake
The magnetic properties of the Tb-honeycomb lattice compound TbPt6Al3, which crystallizes in the NdPt6Al3-type trigonal structure, have been studied by the measurements of electrical resistivity, magnetization M(T, B), and specific heat on single-crystalline samples. The magnetic susceptibility, M(T)/B, for B || c = 0.1 T shows a cusp at TN = 3.5 K, which temperature decreases with increasing the magnitude of B || c, while M(T)/B for B || a = 0.1 T remains constant with decreasing temperature below TN. This anisotropic behavior suggests a collinear antiferromagnetic (AFM) order of the Tb3+ moments pointing along the c axis. The data of M(T)/B for T > 10 K on the single crystal and that of inelastic neutron scattering from powdered samples have been simultaneously analyzed using the crystal field model. The analysis reveals the non-Kramers doublet ground state for the Tb3+ ion under the trigonal crystal field. The neutron powder diffraction measurement shows that the collinear AFM structure with a magnetic propagation vector k = [0, 0, 0] is associated with moments of 5.1 {\mu}B/Tb pointing along the c axis. Comparison of the magnetic point group with the nontrivial spin Laue group indicates that TbPt6Al3 is classified into bulk g-wave altermagnets.
Strongly Correlated Electrons (cond-mat.str-el)
17 pages, 10 figures
How Surface Make-Up and Receding Electrokinetics Determine the Sign and Magnitude of Electrification at Water-Hydrophobe Interfaces?
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-15 20:00 EDT
It has been widely reported that as water contacts hydrophobic materials such as air or hydrocarbons (liquid or solid), the interfaces acquire a negative charge. It is not entirely clear whether this occurs due to the nature of water, or the hydrophobe, or purely the interface. Here, we probe the effects of surface chemistry and the speed of liquid-solid contact formation and separation on electrification. Glass capillaries grafted with mixed self-assembled monolayers of octadecyltrichlorosilane (ODTS) and (3-aminopropy)triethoxysilane (APTES) were exploited. Water was drawn inside these capillaries from an electroneutral reservoir, and the excess charge carried by the pendant droplets, if any, was quantified using an electrometer with a 100 fC resolution. Depending on the APTES content, the surface charge density at the water-hydrophobe interface ranged from negative (for ODTS) to near-neutral (for APTES 2-sec-exposure followed by ODTS) to positive APTES(5s)-ODTS. Next, we probed the charge (Q) contributions of the following steps on the electrification: (i) Contact (Q_1^n): as a dry capillary enters the water reservoir; (ii) Liquid uptake (Q_2^n): as water is uptaken; (iii) Capillary lift (Q_3^n): the filled capillary is removed from the reservoir; and (iv) Liquid release (Q_4^n): releasing the liquid back into the reservoir. This revealed that the electrification during water uptake (Q_2^n) varied with the rate of release during the previous cycle (Q_4^(n-1)), and it did not depend on the uptake rate. We explain these findings based on the electrical double layer theory, electrokinetics, and charge conservation, advancing the current understanding of electrification.
Soft Condensed Matter (cond-mat.soft)
Predicting void nucleation in microstructure with convolutional neural networks
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-15 20:00 EDT
Abhijith Thoopul Anantharanga, Jackson Plummer, Saryu Fensin, Brandon Runnels
Void nucleation in ductile materials subjected to high strain-rate loading remains a critical yet elusive phenomenon to understand. Traditional methods to understand void nucleation typically rely on experiments and molecular dynamics and do not capture the underlying factors leading to void nucleation. In this study, a convolutional neural network, specifically a U-Net enhanced with attention gates is developed, to predict void nucleation probability in pristine tantalum microstructures. The approach leverages a multi-channel input, incorporating four channels of grain orientations and an additional channel of grain boundary energy calculated via the lattice matching method. Void nucleation probability fields are determined from post-mortem micrographs and serve as ground truth, distinguishing void from no-void regions at the pixel level. Pixel-level class imbalance, commen in such images, is addressed by using Focal loss to guide the network’s training to predict void nucleation sites more effectively. The model not only predicts void nucleation sites consistent with ground-truth but also reveals additional potential void nucleation sites, capturing the stochastic nature of void nucleation. This study shows that CNN-based models can predict void nucleation sites while considering combined interplay of factors such as grain boundary energy and grain orientation. In this way, machine learning can serve as a means to understand the underlying factors leading to void nucleation thereby contributing to a fundamental understanding of failure due to spallation in ductile materials.
Materials Science (cond-mat.mtrl-sci)
Possible Spin Triplet Pairing due to Altermagnetic Spin Fluctuation
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-15 20:00 EDT
Xin Ma (1), Siqi Wu (2), Zilong Li (1), Lunhui Hu (1), Jianhui Dai (3 and 4), Chao Cao (1 and 4) ((1) Center for Correlated Matter and School of Physics, Zhejiang University, Hangzhou, China, (2) Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China,(3) School of Physics, Hangzhou Normal University, Hangzhou, China, (4) Institute for Advanced Study in Physics, Zhejiang University, Hangzhou, China)
The interplay between unconventional superconductivity and altermagnetic order has attracted much attentions. In particular, whether spin-triplet superconductivity can be achieved by suppressing altermagnetism remains an open issue. We investigate this issue using a minimal single-orbital Hubbard model on a square lattice with vacancy superstructure, in which both conventional antiferromagnetic and altermagnetic order can emerge on equal footing. We illustrate the existence of a metallic normal phase with altermagnetism even at half-filling due to the geometric frustration and Coulomb interaction. Suppressing the altermagnetic long-range order using charge doping can lead to both conventional antiferromagnetic and altermagnetic spin fluctuation. The spin-singlet pairing is always favored when the conventional antiferromagnetic spin fluctuation dominates. However, when the altermagnetic spin fluctuation dominates, spin-triplet pairing may be induced. Implications of our results in possible material candidates are also briefly discussed.
Superconductivity (cond-mat.supr-con)
Scaling High-Performance Nanoribbon Transistors with Monolayer Transition Metal Dichalcogenides
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-15 20:00 EDT
Tara Peña, Anton E. O. Persson, Andrey Krayev, Áshildur Friðriksdóttir, Kathryn Neilson, Zhepeng Zhang, Anh Tuan Hoang, Jerry A. Yang, Lauren Hoang, Andrew J. Mannix, Paul C. McIntyre, Eric Pop
Nanoscale transistors require aggressive reduction of all channel dimensions: length, width, and thickness. While monolayer two-dimensional semiconductors (2DS) offer ultimate thickness scaling, good performance has largely been achieved only in micrometer-wide channels. Here, we demonstrate both $ \it{n}$ - and $ \it{p}$ -type nanoribbon transistors based on monolayer 2DS, fabricated using a multi-patterning process, reaching channel widths down to 25 nm and lengths down to 50 nm. ‘Anchored’ contacts improve device yield, while nanoscale imaging, including tip-enhanced photoluminescence, reveals minimal edge degradation. The devices reach on-state currents up to 560, 420, and 130 $ \mu$ A $ \mu$ m$ ^{-1}$ at 1 V drain-to-source voltage for $ \it{n}$ -type MoS$ _{2}$ , WS$ _{2}$ , and $ \it{p}$ -type WSe$ _{2}$ , respectively, integrated with thin high-$ \kappa$ dielectrics. These results surpass prior reports for single-gated nanoribbons, the WS$ _{2}$ by over 100 times, even in normally-off (enhancement-mode) transistors. Taken together, these findings suggest that top down patterned 2DS nanoribbons are promising building blocks for future nanosheet transistors.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
16 pages, 4 figures
Impact of Disorder on the Superconducting Properties and BCS-BEC Crossover in FeSe Single Crystals
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-15 20:00 EDT
Jianping Fu, Yue Sun, Jingting Chen, Zhixiang Shi, Tsuyoshi Tamegai
We investigate the crystal structure, transport properties and specific heat in five selected FeSe single crystals containing different amounts of disorder. Transport measurements show that disorder significantly suppresses superconducting transition temperature, $ T_\mathrm{c}$ , and upper critical field, $ H_\mathrm{c2}$ . Specific heat results confirm a robust multi-gap nature, a larger isotropic gap ($ \Delta_\mathrm{s}$ ) and a smaller anisotropic gap ($ \Delta_\mathrm{es}$ ). The smaller gap $ \Delta_\mathrm{es}$ becomes more isotropic with increasing disorder. Additionally, FeSe is regarded as a superconductor in the crossover regime from Bardeen-Cooper-Schrieffer (BCS) to Bose-Einstein condensation (BEC) because of its comparable $ \Delta$ and Fermi energy $ E_\mathrm{F}$ . By introducing disorder, the BCS-BEC crossover in FeSe can be tuned closer to BCS limit, reducing $ \Delta/E_\mathrm{F}$ from 1.3 to 0.4.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
8 pages, 5 figures
Supercond. Sci. Technol. 38 095003 (2025)
Elemental Frequency-Based Supervised Classification Approach for the Search of Novel Topological Materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-15 20:00 EDT
Zodinpuia Ralte, Ramesh Kumar, Mukhtiyar Singh
The machine learning based approaches efficiently solves the goal of searching the best materials candidate for the targeted properties. The search for topological materials using traditional first-principles and symmetry-based methods often requires lots of computing power or is limited by the crystalline symmetries. In this study, we present frequency-based statistical descriptors for machine learning-driven topological material’s classification that is independent of crystallographic symmetry of wave functions. This approach predicts the topological nature of a material based on its chemical formula. With a balanced dataset of 3910 materials, we have achieved classification accuracies of 82% with the Support Vector Machine (SVM) model and 83% with the Random Forest (RF) model, where both models have trained on common frequency based features. We have checked the performances of the models using $ 5-fold$ cross-validation approach. Further, we have validated the models on a dataset of unseen binary compounds and have efficiently identified 22 common materials using both the models. Next, we implemented the $ first-principles$ approach to confirm the topological nature of these predicted materials and found the topological signatures of Dirac, Weyl, and nodal-line semimetallic phases. Therefore, we have demonstrated that the implications of frequency-based descriptors is a practical and less complex way to find novel topological materials with certain physical post-processing filters. This approach lays the groundwork for scalable, data-driven topological property screening of complex materials.
Materials Science (cond-mat.mtrl-sci)
10 pages, 9 figures, 6 tables
Entanglement architecture of beyond-Landau quantum criticality
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-15 20:00 EDT
Menghan Song, Ting-Tung Wang, Liuke Lyu, William Witczak-Krempa, Zi Yang Meng
Quantum critical points beyond the Landau paradigm exhibit fractionalized excitations and emergent gauge fields. Here, we use entanglement microscopy–full tomography of the reduced density matrix of small subregions and subsequent extraction of their quantum correlations–to resolve the entanglement architecture near such exotic critical points. We focus on genuine multipartite entanglement (GME). Through unbiased quantum Monte Carlo sampling of RDMs across conventional O(2)/O(3) Wilson-Fisher transitions, and unconventional XY$ ^\ast$ , and Néel-VBS transitions in (2+1)d, we discover a dichotomy: Landau criticality amplifies GME within compact subregions, while non-Landau criticality redistributes entanglement into larger, loopy configurations. Key signatures at non-Landau criticality include the absence of three-spin GME, and the loss of non-loopy entanglement in unicursal regions. Similar results in a critical resonating valence bond wavefunction confirm this multipartite entanglement structure as a common feature of emergent gauge theories. Our findings reveal a distinct entanglement architecture in beyond-Landau quantum critical theories.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
10 pages, 9 figures
Unveiling the Role of Solvents in DBTTF:HATCN Ternary Cocrystals
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-15 20:00 EDT
Ana M. Valencia, Lisa Schraut-May, Marie Siegert, Sebastian Hammer, Beatrice Cula, Alexandra Friedrich, Holger Helten, Jens Pflaum, Caterina Cocchi, Andreas Opitz
Donor-acceptor (D:A) cocrystals offer a promising platform for next-generation optoelectronic applications, but the impact of residual solvent molecules on their properties remains an open question. We investigate six novel D:A cocrystals of dibenzotetrathiafulvalene (DBTTF) and 1,4,5,8,9,11-hexaazatriphenylenehexacarbo-nitrile (HATCN), prepared via solvent evaporation, yielding 1:1 molar ratios, and horizontal vapor deposition, resulting in solvent-free 3:2 cocrystals. Combining spectroscopy and density-functional theory (DFT) calculations, we find that, while the electronic and optical properties of the cocrystals are largely unaffected by solvent inclusion, the charge transfer mechanism is surprisingly complex. Raman spectroscopy reveals a consistent charge transfer of 0.11 $ e$ across all considered structures, corroborated by DFT calculations on solvent-free systems. Partial charge analysis reveals that in solvated cocrystals, solvent molecules actively participate in the charge transfer process as primary electron acceptors. This involvement can perturb the expected D:A behavior, revealing a faceted charge-transfer mechanism in HATCN even beyond the established involvement of its cyano group. Overall, our study demonstrates that while solution-based methods preserve the intrinsic D:A characteristics, solvents can be leveraged as active electronic components, opening new avenues for material design.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
Bond percolation in distorted square and triangular lattices
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-15 20:00 EDT
Bishnu Bhowmik, Sayantan Mitra, Robert M Ziff, Ankur Sensharma
This article presents a Monte Carlo study on bond percolation in distorted square and triangular lattices. The distorted lattices are generated by dislocating the sites from their regular positions. The amount and direction of the dislocations are random, but can be tuned by the distortion parameter $ \alpha$ . Once the sites are dislocated, the bond lengths $ \delta$ between the nearest neighbors change. A bond can only be occupied if its bond length is less than a threshold value called the connection threshold $ d$ . It is observed that when the connection threshold is greater than the lattice constant (assumed to be $ 1$ ), the bond percolation threshold $ p_\mathrm{b}$ always increases with distortion. For $ d\le 1$ , no spanning configuration is found for the square lattice when the lattice is distorted, even very slightly. On the other hand, the triangular lattice not only spans for $ d\le 1$ , it also shows a decreasing trend for $ p_\mathrm{b}$ in the low-$ \alpha$ range. These variation patterns have been linked with the average coordination numbers of the distorted lattices. A critical value $ d_\mathrm{c}$ for the connection threshold has been defined as the value of $ d$ below which no spanning configuration can be found even after occupying all the bonds satisfying the connection criterion $ \delta\le d$ . The behavior of $ d_\mathrm{c}(\alpha)$ is markedly different for the two lattices.
Statistical Mechanics (cond-mat.stat-mech)
12 pages, 9 figures, Accepted in Phys. Rev. E
Orthogonality between cellulose nanocrystals and a low-molecular weight gelator
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-15 20:00 EDT
Thuy-Linh Phi (LCMCP-SMiLES), Eero Kontturi, Niki Baccile (LCMCP-SMiLES)
The development of multicomponent hydrogels has gained a lot of attention in the field of soft matter, as precise tuning of the chemical nature and colloidal properties of each component brings mechanical and functional benefits compared to one-component gels. Within the field, orthogonality between a self-assembled low-molecular weight gelator (LMWG) and a colloid is a domain that has received little attention. In this study, orthogonal LMWG-colloid hydrogels were developed with the additional constraint of sustainability: a bolaamphiphile glycolipid (G-C18:1) is selected as LMWG while cellulose nanocrystals (CNCs) as colloid. These compounds are chosen for their dual role. G-C18:1 is a LMWG but it can also be used, at lower concentrations, as surface stabilizer for CNCs and tune its aggregative properties. On the other hand, tuning surface properties of CNCs drives its bulk behavior: uncharged CNCs locally aggregate and act as reinforcing agent for the LMWG gel, while negatively-charged CNCs, cross-linked with Ca 2+ , naturally form a hydrogel, which can interpenetrate with the LMWG network. By means of rheometry, small-angle X-ray scattering (SAXS) and rheo-SAXS, it is shown here how the aggregative behavior of CNCs enhances the mechanical properties of G-C18:1 hydrogels, while G-C18:1 imparts pH and temperature responsiveness to CNC hydrogels. An interesting field of research in soft matter science is the development of orthogonal hydrogels containing cellulose and LMWGs, although, to the best of our knowledge, there are no existing reports. Since cellulose is among the most extensively studied macromolecules in the field of soft matter, particularly for biomedical applications, 22,23 developing and studying the properties of orthogonal hydrogels containing CNCs and a LMWG represents an intriguing avenue for research, and this for two reasons. First of all, CNCs are bio-based nanoparticles, relevant for the development of sustainable nanoscale science and engineering. Secondly, the surface chemistry of CNCs can be controlled in such a way to tune their aggregation and dispersion properties, making them interesting either as reinforcements in hydrogels, 24,25 or as hydrogel scaffold themselves. 26,27 These aspects were never explored in the context of orthogonal hydrogels. In this work, we then study orthogonality in fully bio-based hydrogels composed of a single glucose lipid LMWG (G-C18:1) and CNCs. G-C18:1 is selected for its multiphasic behavior in water at room temperature 28 and linked to its unique surfactant-lipid-gelator nature, 28,29 tuned by pH and/or type of ion. Below neutral pH and at concentrations under 5 wt%, G-C18:1 forms vesicles, displaying a lipid-like behavior. At pH above neutrality, it assembles into micelles, thus exhibiting a surfactant behavior. 30,31 When Ca 2+ is added to its micellar phase, 32,33 G-C18:1 forms fiber gels 30 (Figure 1). In particular, we focused on orthogonal G-C18:1/CNC hydrogels, in which CNCs either assembled into hydrogels (negatively-charged and cross-linked by calcium ions, referred to as SCNCs, Figure 1) or behaved as reinforcing agents (uncharged CNCs prepared via HCl hydrolysis, referred to as CNC$ \alpha$ , and neutral surface stabilized by G-C18:1, 34 Figure 1). These two types of CNCs exhibit distinct roles in the hydrogel system: SCNCs actively participate in the formation of a percolated network, while CNC$ \alpha$ are used to reinforce the hydrogel matrix physically. Specific attention is paid to the impact of the assembled form of CNCs to the elastic properties of the LMWG hydrogel as well as how the responsivity to pH and temperature of the LMWG affect the elastic properties of CNC hydrogels. 33
Soft Condensed Matter (cond-mat.soft)
Journal of Colloid and Interface Science, 2025, pp.138995
Switching magnetic texture via in-plane magnetic field in noncentrosymmetric dipolar magnets: From skyrmions to antiskyrmions and nontopological magnetic bubbles
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-15 20:00 EDT
Tatsuki Muto, Masahito Mochizuki
We theoretically investigate field-induced switching of magnetic topology in a nanodisk-shaped sample of noncentrosymmetric dipolar magnet in which the Dzyaloshinskii-Moriya interaction that stabilizes an antiskyrmion with $ N_{\rm sk}$ =+1 and the magnetic dipole interaction that stabilizes a skyrmion with $ N_{\rm sk}$ =$ -1$ are in keen competition where $ N_{\rm sk}$ is the skyrmion number. Our micromagnetic simulations demonstrate that the competition offers a unique opportunity to switch magnetic textures with distinct magnetic topology among the antiskyrmion ($ N_{\rm sk}$ =+1), elliptical skyrmion ($ N_{\rm sk}$ =$ -1$ ), and nontopological bubble ($ N_{\rm sk}$ =0) in a deterministic manner by application of magnetic fields parallel to the sample plane. By calculating time and spatial profiles of energy contributions from respective interactions and magnetic anisotropy, we clarify the physical mechanism and properties of the observed field-induced topology switching phenomena. Our findings are expected to provide useful insights into the spintronic application of topological magnetism.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
14 pages, 9 figures
Universal Driven Critical Dynamics near the Boundary
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-15 20:00 EDT
The celebrated Kibble-Zurek mechanism (KZM) describes the scaling of physical quantities when external parameters sweep through a critical point. Boundaries are ubiquitous in real systems, and critical behaviors near the boundary have attracted extensive research. Different boundary universality classes, including ordinary, special, extraordinary, and surface transitions, have been identified. However, the driven critical dynamics near boundaries remains unexplored. Here, we systematically investigate the driven critical dynamics in various boundary universality classes of the Ising model in both two and three dimensions, and discover a wealth of dynamic scaling behaviors. We find that for heating dynamics in all boundary universality classes, as well as for cooling dynamics in special, extraordinary, and surface transitions, the dynamic scaling behaviors of the order parameter can be described by a normal generalization of the KZM, called boundary finite-time scaling (BFTS). In contrast, for cooling dynamics in ordinary transition, we discover an abnormal logarithmic scaling on the driving rate. Moreover, for the special transition, in addition to temperature driving, we also consider the driven dynamics by driving the surface couplings. For increasing the surface coupling across the special transition point along the line of the ordinary transition, the prerequisite of the KZM, which requires that the correlation length/time in the initial state to be short-ranged, breaks down. We develop a generalized BFTS for a nonequilibrium initial state characterized by the waiting time, or the ``age’’, of the boundary. Possible generalizations are also discussed.
Statistical Mechanics (cond-mat.stat-mech)
17 pages, 15 figures
Radial Rashba spin-orbit fields in commensurate twisted transition-metal dichalcogenide bilayers
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-15 20:00 EDT
Thomas Naimer, Paulo E. Faria Junior, Klaus Zollner, Jaroslav Fabian
In commensurate twisted homobilayers, purely radial Rashba spin-orbit fields can emerge. The observed in-plane spin textures are mostly radial, and the main features are successfully reproduced using a model Hamiltonian based on two effective mass models including spin-orbit coupling, and a general (spin-conserving) interlayer coupling. Extracting the model Hamiltonian parameters through fitting of several twisted supercells, we find a twist angle dependency of the magnitude of the radial Rashba field, which is symmetric not only around the untwisted cases ($ \Theta=0^\circ$ and $ \Theta=60^\circ$ ), but also around $ \Theta=30^\circ$ . Furthermore, we observe that the interlayer coupling between the $ K/K’$ -points of the two layers decreases with the increase of the size of the commensurate supercells. Hence, peaks of high interlayer coupling can occur only for twist angles, where small commensurate supercells are possible. Exploring different lateral displacements between the layers, we confirm that the relevant symmetry protecting the radial Rashba is an in-plane 180$ ^\circ$ rotation axis. We additionally investigate the effects of atomic relaxation and modulation of the interlayer distance. Our results offer fundamental microscopic insights that are particularly relevant to engineering spin-charge conversion schemes based on twisted layered materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Intrinsic disorder in the candidate quantum spin ice Pr$_2$Zr$_2$O$_7$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-15 20:00 EDT
T. J. Hicken, P. Meadows, D. Prabhakaran, A. Szabó, S. E. Dutton, C. Castelnovo, K. Moovendaran, T. S. Northam de la Fuente, L. Mangin-Thro, G. B. G. Stenning, M. J. Gutmann, G. Sala, M. B. Stone, P. F. Henry, D. J. Voneshen, J. P. Goff
Quantum spin liquids with long-range entanglement are of great interest for applications in quantum technology. The quantum spin ice Pr$ _2$ Zr$ _2$ O$ _7$ is a promising example, where it is believed that structural disorder plays a key role in enhancing quantum mechanical effects by introducing strains that split the ground state doublet akin to the effect of a local disordered transverse field. However, the precise defect structure responsible for this behaviour is unknown. Here we have determined the intrinsic defect structure of Pr$ _2$ Zr$ _2$ O$ _7$ using neutron and x-ray scattering techniques supported by density functional theory. We find the main defect is the stuffing of Zr$ ^{4+}$ sites by Pr$ ^{3+}$ ions, accompanied by charge compensating O$ ^{2-}$ vacancies, and the relaxation of a neighbouring O$ ^{2-}$ ion to an interstitial site. Our results explain the single-ion magnetism by considering the non-magnetic singlets that arise on neighbouring sites as a result of the defect structure. These singlets account for additional features in the crystal electric field excitations. The effects caused by this low level of structural disorder are magnified since several neighbouring Pr sites are affected. This makes a significant contribution towards the observed broadening of pinch points in the magnetic diffuse scattering, which was previously attributed purely to quantum effects.
Strongly Correlated Electrons (cond-mat.str-el)
9 pages, 3 figures
Resolving the Bulk-Boundary Correspondence Paradox on Low-Symmetry Surfaces of Weyl Semimetals
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-15 20:00 EDT
Cong Li, Zhilong Yang, Hongxiong Liu, Magnus H. Berntsen, Francesco Scali, Dibya Phuyal, Jianfeng Zhang, Timur K. Kim, Jacek Osiecki, Balasubramanian Thiagarajan, Youguo Shi, Tao Xiang, Quansheng Wu, Oscar Tjernberg
Low-symmetry surfaces of topological semimetals offer access to boundary phenomena hidden on conventional facets, yet systematic studies remain scarce due to experimental challenges and the lack of a general framework for reconciling bulk and surface periodicities. Here, we investigate the (103) surface of the Weyl semimetal NdAlSi using angle resolved photoemission spectroscopy and density functional theory. The (103) surface is an example of a low symmetry surface that presents an apparent paradox to the bulk-boundary correspondence. The surface periodicity to which the topological surface states are expected to adhere does not correspond to the bulk periodicity of the Weyl points. By showing that successive bulk Brillouin zones generate replicas that accumulate into a superlattice commensurate with the surface Brillouin zone, we demonstrate how the apparent bulk boundary correspondence paradox is resolved and establish a universal criterion for arbitrary facets. The framework and experimental results further suggests that overlapping Fermi arcs can hybridize into closed Fermi arc loops, enriching boundary topology and enabling unconventional transport, interference, and collective phenomena unique to lowsymmetry facets.
Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other), Strongly Correlated Electrons (cond-mat.str-el)
Main text: 18 pages, 4 figures; SI: 29 pages, 16 figures. Comments are welcome
Instability and self-propulsion of flexible autophoretic filaments
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-15 20:00 EDT
Ursy Makanga, Akhil Varma, Panayiota Katsamba
Over the past decade, autophoretic colloids have emerged as a prototypical system for studying self-propelled motion at microscopic scales, with promising applications in microfluidics, micro-machinery, and therapeutics. Their motion in a viscous fluid hinges on their ability to induce surface slip flows that are spatially asymmetric, from self-generated solute gradients. Here, we demonstrate theoretically that a straight elastic filament with homogeneous surface chemical properties – which is otherwise immotile – can spontaneously achieve self-propulsion by experiencing a buckling instability that serves as the symmetry-breaking mechanism. Using efficient numerical simulations, we characterize the nonlinear dynamics of the elastic filament and show that, over time, it attains distinct swimming modes such as a steadily translating “U” shape and a metastable rotating “S” shape when semi-flexible, and an oscillatory state when highly flexible. Our findings provide physical insight into future experiments and the design of reconfigurable synthetic active colloids.
Soft Condensed Matter (cond-mat.soft), Fluid Dynamics (physics.flu-dyn)
29 pages, 7 figures
Novel 3D Pentagraphene Allotropes: Stability, Electronic, Mechanical, and Optical Properties
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-15 20:00 EDT
I. M. Félix, B. Ipaves, R. B. de Oliveira, L. A. Ribeiro Junior, L. S. Rocha, M. L. Pereira Junior, D. S. Galvão, R. M. Tromer
Carbon-based materials have attracted great attention due to their exceptional structural diversity and wide-ranging applications. Recently, a new two-dimensional carbon allotrope, named pentagraphene (PG), was proposed. In this study, we proposed three novel three-dimensional (3D) PG allotropes, named 3D-PG-$ \alpha$ , -$ \beta$ , and -$ \gamma$ , engineered through biaxial strain and controlled compression of 2D PG layers. Comprehensive stability analyses, including phonon dispersion and ab initio molecular dynamics simulations (AIMD), confirm their thermodynamic stability under room and high-temperature conditions. 3D-PG-$ \alpha$ is the most stable, exhibiting a cohesive energy 0.5 eV/atom lower than the least stable structure, 3D-PG-$ \gamma$ . Electronic property characterization reveals semiconducting behavior for all structures, with indirect electronic band gaps ranging from 0.91 to 2.67 eV. The analyses of the mechanical properties showed significant anisotropy, with higher stiffness along the in-plane ($ xy$ -plane) direction. Optical properties highlight strong absorption along a wide range and a pronounced anisotropic response. Additionally, the absorption spectra exhibit activity in the visible region, and the refractive index and reflectivity indicate potential use in ultraviolet-blocking devices.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
Spectroscopy and transport of nonpolarons in silicon and germanium: the influence of doping and temperature
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-15 20:00 EDT
Raveena Gupta, Joao Abreu, Matthieu J. Verstraete
We perform a first-principles investigation of electron-phonon interactions in silicon and germanium, uncovering distinct non-polaronic spectral and transport fingerprints in these archetypal covalent semiconductors. Using many-body perturbation theory with the retarded cumulant expansion, we compute quasiparticle energies, lifetimes, and phonon satellites beyond the Dyson-Migdal approximation. Short-range crystal fields dominate coupling in both materials, yet their low-temperature spectral fingerprints differ: Si exhibits well-resolved satellites at both band edges, whereas Ge displays strong sidebands mainly at the valence band maximum (VBM) and much weaker features at the conduction band minimum (CBM). Phonon-induced satellites in both materials broaden and merge with the quasiparticle peak at elevated temperatures. Doping broadens peaks and compresses satellite-quasiparticle separation, with n-type carriers affecting the CBM and p-type the VBM. Mobility calculations, combining cumulant-derived phonon scattering with experimentally motivated ionized-impurity scattering models, reproduce measured trends and reveal Ge’s consistently higher mobilities than Si, stemming from lighter effective masses and weaker coupling. These results link band-edge asymmetries and phonon energetics to measurable transport differences, providing a unified framework for predicting mobility in nonpolar semiconductors.
Materials Science (cond-mat.mtrl-sci)
Magnetism Induced by Azanide and Ammonia Adsorption in Defective Molybdenum Disulfide and Diselenide: A First-Principles Study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-15 20:00 EDT
Guilherme S. L. Fabris, Bruno Ipaves, Raphael B. Oliveira, Humberto R. Gutierrez, Marcelo L. Pereira Junior, Douglas S. Galvão
Two-dimensional (2D) transition metal dichalcogenides (TMDs) have attracted considerable attention due to their tunable structural, electronic, and spin-related properties, particularly in the presence of point defects and molecular adsorbates. Motivated by these aspects, we have investigated using first-principles methods the magnetic properties induced by azanide (NH$ _2$ ) and ammonia (NH$ _3$ ) adsorption on defective monolayers of Molybdenum Disulfide (MoS$ _2$ ) and Diselenide(MoSe$ _2$ ). Spin-polarized density functional theory (DFT) was employed to investigate the impact of mono- and di-vacancies on the local spin environment and the role of molecular adsorption in modifying magnetic behavior. The results show that pristine chalcogen vacancies do not generate magnetism, whereas the adsorption of NH$ _2$ and NH$ _3$ creates localized magnetic moments in Mo-based dichalcogenides. A notable case occurs for MoSe$ _2$ , where NH$ _3$ dissociation into NH$ _2$ and H fragments on the same side of the surface produces a net magnetic moment of 2.0 $ \mu_B$ . Tests performed on W-based dichalcogenides under equivalent conditions showed no magnetic response, and are reported here only for comparison. These findings demonstrate that molecular adsorption combined with defect engineering can be a practical approach to tune magnetism in 2D materials, with potential relevance for spintronic and sensing applications.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
Direct evidence for the absence of coupling between shear strain and superconductivity in Sr2RuO4
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-15 20:00 EDT
Giordano Mattoni, Thomas Johnson, Atsutoshi Ikeda, Shubhankar Paul, Jake Bobowski, Manfred Sigrist, Yoshiteru Maeno
The superconducting symmetry of Sr2RuO4 has been intensely debated for many years. A crucial controversy recently emerged between shear-mode ultrasound experiments, which suggest a two-component order parameter, and some uniaxial pressure experiments that suggest a one-component order parameter. To resolve this controversy, we use a new approach to directly apply three different kinds of shear strain to single crystals of Sr2RuO4 and investigate the coupling to superconductivity. After characterising the strain by optical imaging, we observe variations of the transition temperature Tc smaller than 10mK/% as measured by low-frequency magnetic susceptibility, indicating that shear strain has little to no coupling to superconductivity. Our results are consistent with a one-component order parameter model, but such a model cannot consistently explain other experimental evidence such as time-reversal symmetry breaking, superconducting domains, and horizontal line nodes, thus calling for alternative interpretations.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Competitive Adsorption of Toluene and Water in MFI-type Zeolites
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-15 20:00 EDT
Gavriel Arbiv, Sambhu Radhakrishnan, Alysson F. Morais, C. Vinod Chandran, Dries Vandenabeele, Dirk Dom, Karel Duerinckx, Christine E. A. Kirschhock, Eric Breynaert
Competitive adsorption is a major challenge in understanding catalytic activity, selectivity and reaction mechanisms in confined environments such as zeolites. This study investigated competitive adsorption in MFI-type zeolites (ZSM-5) using solid-state NMR, focusing on the interplay between toluene and water. Quantitative 1H NMR spectroscopy identified three distinct populations of adsorbed toluene evolving with increasing toluene loading. The adsorption behavior was consistent across a series of samples with Si/Al ratio ranging from 11.5 to 140. Combining 1D and 2D NMR techniques with sample engineering (e.g. pore-blocking) enabled the assignment of the populations to toluene within the zeolite channels, at the pore mouths, and adsorbed on the external crystal surface. Crucially, introducing water to toluene-loaded zeolites caused a partial displacement of toluene from the internal channels, but significant removal from the pore mouths. This dis-placement occurred even in the highly hydrophobic zeolite (Si/Al = 140), where water still preferentially adsorbed to Brønsted acid sites and silanol species. The results highlight the critical impact that competitive adsorption from solvents, products, or impurities can have on the efficiency and selectivity of zeolite-mediated transformations.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
Anomalous Electrical Transport in SnSe$_2$ Nanosheets: Role of Thickness and Surface Defect States
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-15 20:00 EDT
Aarti Lakhara, Lars Thole, Rolf J. Haug, P. A. Bhobe
This work examines the influence of thickness on the electrical transport properties of mechanically exfoliated two-dimensional SnSe$ _2$ nanosheets, derived from the bulk single crystal. Contrary to conventional trend observed in two-dimensional systems, we find a semiconducting to metallic resistivity behavior with decreasing thickness. The analysis of low-temperature conduction indicates an increased density of states at Fermi-level with decreasing thickness, which is further corroborated by gate bias dependent conductance measurement. The enhanced conductivity in thinner flake is attributed to the n-type doping arising from surface defect states. The presence and evolution of these defect states with thickness is probed by thickness-dependent room-temperature Raman spectroscopy. Our study provides insights into the thickness-dependent electronic transport mechanism of SnSe$ _2$ and the crucial role of defect states in governing the observed conductivity behavior.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Noncontact friction in ultracoherent nanomechanical resonators near dielectric materials
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-15 20:00 EDT
Amirali Arabmoheghi, Alessio Zicoschi, Guillermo Arregui, Mohammad J. Bereyhi, Yi Xia, Nils J. Engelsen, Tobias J. Kippenberg
Micro- and nanomechanical resonators are emerging as promising platforms for quantum technologies, precision sensors and fundamental science experiments. To utilize these devices for force sensing or quantum optomechanics, they must be brought in close proximity with other systems for functionalization or efficient readout. Improved understanding of the loss mechanisms in nanomechanical resonators, specifically the advent of dissipation dilution, has led to the development of resonators with unprecedented coherence properties. The mechanical quality factors of this new class of ultracoherent micro- and nanomechanical oscillators can now exceed 1 billion at room temperature, setting their force sensitivities below 1 $ \mathrm{aN}/\sqrt{\mathrm{Hz}}$ , surpassing those of the state-of-the-art atomic force microscopes (AFMs). Given this new regime of sensitivity, an intriguing question is whether the proximity of other materials hinders mechanical coherence. Here we show: it does. We report a novel dissipation mechanism that occurs in ultracoherent nanomechanical oscillators caused by the presence of nearby dielectrics. By studying the parameter scaling of the effect, we show that the mechanism is more severe for low-frequency mechanical modes and that it is due to dielectric loss within the materials caused by the motion of a resonator which carries static charges. Our observations are consistent with the noncontact friction (NCF) observed in AFMs. Our findings provide insights into limitations on the integration of ultracoherent nanomechanical resonators and highlight the adverse effects of charged defects in these systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph), Quantum Physics (quant-ph)
Pure dephasing increases partition noise in the quantum Hall effect
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-15 20:00 EDT
Quantum Hall edge channels partition electric charge over N chiral (uni-directional) modes. Intermode scattering leads to partition noise, observed in graphene p-n junctions. While inelastic scattering suppresses this noise by averaging out fluctuations, we show that pure (quasi-elastic) dephasing may enhance the partition noise. The noise power increases by up to 50% for two modes, with a general enhancement factor of 1+1/N in the strong-dephasing limit. This counterintuitive effect is explained in the framework of monitored quantum transport, arising from the self-averaging of quantum trajectories.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
9 pages, 6 figures
Interplay of vibrational, electronic, and magnetic states in CrSBr
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-15 20:00 EDT
Daria I. Markina, Priyanka Mondal, Lukas Krelle, Sai Shradha, Mikhail M. Glazov, Regine von Klitzing, Kseniia Mosina, Zdenek Sofer, Bernhard Urbaszek
The van der Waals antiferromagnet CrSBr exhibits coupling of vibrational, electronic, and magnetic degrees of freedom, giving rise to distinctive quasi-particle interactions. We investigate these interactions across a wide temperature range using polarization-resolved Raman spectroscopy at various excitation energies, complemented by optical absorption and photoluminescence excitation (PLE) spectroscopy. Under 1.96 eV excitation, we observe pronounced changes in the A$ _g^1$ , A$ _g^2$ , and A$ _g^3$ Raman modes near the Néel temperature, coinciding with modifications in the oscillator strength of excitonic transitions and clear resonances in PLE. The distinct temperature evolution of Raman tensor elements and polarization anisotropy for Raman modes indicates that they couple to different excitonic and electronic states. The suppression of the excitonic state’s oscillation strength above the Néel temperature could be related to the magnetic phase transition, thereby connecting these excitonic states and Raman modes to a specific spin alignment. These observations make CrSBr a versatile platform for probing quasi-particle interactions in low-dimensional magnets and provide insights for applications in quantum sensing and quantum communication.
Materials Science (cond-mat.mtrl-sci)
Magnetic Field Dependence of Critical Fluctuations in CeCu${5.8}$Ag${0.2}$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-15 20:00 EDT
X. Boraley, A. D. Christianson, J. Lass, C. Balz, M. Bartkowiak, Ch. Niedermayer, J. M. Lawrence, L. Poudel, D. G. Mandrus, F. Ronning, M. Janoschek, D. G. Mazzone
Quantum phase transitions are among the most intriguing phenomena that can occur when the electronic ground state of correlated metals are tuned by external parameters such as pressure, magnetic field or chemical substitution. Such transitions between distinct states of matter are driven by quantum fluctuations, and can give rise to macroscopically coherent phases that are at the forefront of condensed matter research. However, the nature of the critical fluctuations, and thus the fundamental physics controlling many quantum phase transitions, remain poorly understood in numerous strongly correlated metals. Here we study the model material CeCu$ _{5.8}$ Ag$ _{0.2}$ to gain insight into the implications of critical fluctuations originating from different regions in reciprocal space. By employing an external magnetic field along the crystallographic $ a$ - and $ c$ -axis as auxiliary tuning parameter we observe a pronounced anisotropy in the suppression of the quantum critical fluctuations, reflecting the spin anisotropy of the long-range ordered ground state at larger silver concentration. Coupled with the temperature dependence of the quantum critical fluctuations, these results suggest that the quantum phase transition in CeCu$ _{5.8}$ Ag$ _{0.2}$ is driven by three-dimensional spin-density wave fluctuations.
Strongly Correlated Electrons (cond-mat.str-el)
OpenCSP: A Deep Learning Framework for Crystal Structure Prediction from Ambient to High Pressure
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-15 20:00 EDT
Yinan Wang, Xiaoyang Wang, Zhenyu Wang, Jing Wu, Jian Lv, Han Wang
High-pressure crystal structure prediction (CSP) underpins advances in condensed matter physics, planetary science, and materials discovery. Yet, most large atomistic models are trained on near-ambient, equilibrium data, leading to degraded stress accuracy at tens to hundreds of gigapascals and sparse coverage of pressure-stabilized stoichiometries and dense coordination motifs. Here, we introduce OpenCSP, a machine learning framework for CSP tasks spanning ambient to high-pressure conditions. This framework comprises an open-source pressure-resolved dataset alongside a suite of publicly available atomistic models that are jointly optimized for accuracy in energy, force, and stress predictions. The dataset is constructed via randomized high-pressure sampling and iteratively refined through an uncertainty-guided concurrent learning strategy, which enriches underrepresented compression regimes while suppressing redundant DFT labeling. Despite employing a training corpus one to two orders of magnitude smaller than those of leading large models, OpenCSP achieves comparable or superior performance in high-pressure enthalpy ranking and stability prediction. Across benchmark CSP tasks spanning a wide pressure window, our models match or surpass MACE-MPA-0, MatterSim v1 5M, and GRACE-2L-OAM, with the largest gains observed at elevated pressures. These results demonstrate that targeted, pressure-aware data acquisition coupled with scalable architectures enables data-efficient, high-fidelity CSP, paving the way for autonomous materials discovery under ambient and extreme conditions.
Materials Science (cond-mat.mtrl-sci)
15 pages, 5 figures
Self-locking and Stability of the Bowline Knot
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-15 20:00 EDT
Bastien F.G. Aymon, Fani Derveni, Michael Gomez, Jérôme Crassous, Pedro M. Reis
We investigate the self-locking of the bowline knot through numerical simulations, experiments, and theoretical analysis. Specifically, we perform two complementary types of simulations using the 3D finite-element method (FEM) and a reduced-order model based on the discrete-element method (DEM). For the FEM simulations, we develop a novel mapping technique that automatically transforms the centerline of the rod into the required knot topology prior to loading. In parallel, we conduct experiments using a nearly inextensible elastic rod tied into a bowline around a rigid cylinder. One end of the rod is pulled to load the knot while the other is left free. The measured force-displacement response serves to validate both the FEM and DEM simulations. Leveraging these validated computational frameworks, we analyze the internal tension profile along the rod’s centerline, revealing that a sharp drop in tension concentrates around a strategic locking region, whose geometry resembles that observed in other knot types. By considering the coupling of tension, bending, and friction, we formulate a theoretical model inspired by the classic capstan problem to predict the stability conditions of the bowline, finding excellent agreement with our FEM and DEM simulations. Our methodology and findings offer new tools and insights for future studies on the performance and reliability of other complex knots.
Soft Condensed Matter (cond-mat.soft)
9 pages, 4 figures in main text, 1 figure in appendix
Spin-qubit Noise Spectroscopy of Magnetic Berezinskii-Kosterlitz-Thouless Physics
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-15 20:00 EDT
We propose using spin-qubit noise magnetometry to probe dynamical signatures of magnetic Berezinskii-Kosterlitz-Thouless (BKT) physics. For a nitrogen-vacancy (NV) center coupled to two-dimensional XY magnets, we predict distinctive features in the magnetic noise spectral density in the sub-MHz to GHz frequency range. In the quasi-long-range ordered phase, the spectrum exhibits a temperature-dependent power law characteristic of algebraic spin correlations. Above the transition, the noise reflects the proliferation of free vortices and enables quantitative extraction of the vortex conductivity, a key parameter of vortex transport. These results highlight NV as a powerful spectroscopic method to resolve magnetic dynamics in the mesoscopic and low-frequency regimes and to probe exotic magnetic phase transitions.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
5 pages, 3 figures
Breakdown of the critical state in the ferromagnetic superconductor EuFe$2$(As${1-x}$P$_x$)$_2$
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-15 20:00 EDT
William Robert Fern, Joseph Alec Wilcox, Tong Ren, Ivan Veshchunov, Tsuyoshi Tamegai, Simon John Bending
There are very few materials in which ferromagnetism coexists with superconductivity due to the destructive effect of the magnetic exchange field on singlet Cooper pairs. The iron-based superconductor EuFe$ _2$ (As$ _{1-x}$ P$ x$ )$ 2$ is therefore unique in exhibiting robust superconductivity with a maximum critical temperature of 25 K and long-range ferromagnetism below $ T\mathrm{FM}\approx19$ K. Here we report a spatially-resolved study of the irreversible magnetisation in this system that reveals a variety of novel behaviours that are strongly linked with underlying ferromagnetic domain structures. In the superconducting-only state, hysteretic magnetisation due to irreversible vortex motion is consistent with typical weak vortex-pinning behaviour. Just below $ T\mathrm{FM}$ , very narrowly-spaced stripe domains give rise to highly erratic and irreproducible fluctuations in the irreversible magnetisation that we attribute to the dynamics of multi-vortex clusters stabilised by the formation of vortex polarons. In contrast, at lower temperatures, ferromagnetic domains become wider and saturated with spontaneously nucleated vortices and antivortices, leading to a smoother but unconventional evolution of the irreversible state. This observation suggests that the penetrating flux front is roughened by the presence of the magnetic domains in this regime, presenting a clear departure from standard critical state models. Our findings indicate that the mechanism governing irreversibility is strongly influenced by the precise nature of the underlying ferromagnetic domains, being very sensitive to the specific material parameters of EuFe$ _2$ (As$ _{1-x}$ P$ _x$ )$ _2$ . We consider the possible microscopic origins of these effects, and suggest further ways to explore novel vortex-domain magnetic behaviours.
Superconductivity (cond-mat.supr-con)
24 + 1 pages, 6 figures
Disorder-driven Weyl-Kondo Semimetal Phase in WTe$_2$
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-15 20:00 EDT
Arpan Manna, Sunit Das, Amit Agarwal, Soumik Mukhopadhyay
In this Letter, we report the observation of disorder-driven anisotropic Kondo screening and spontaneous Hall effect in bulk WTe$ {_2}$ , a nonmagnetic type-II Weyl semimetal. We show that Kondo scattering emerges more prominently in disordered samples and produces magnetoresistance that is strongly anisotropic with respect to both current and magnetic field orientation, reflecting the underlying type-II Weyl dispersion. Strikingly, we find a spontaneous Hall effect in zero magnetic field, whose magnitude is enhanced with disorder, together with a large second-harmonic Hall signal exhibiting quadratic current scaling. Our analysis indicates that disorder-driven Kondo interactions pin the Fermi level near the Weyl nodes. This enhances the Berry curvature-driven nonequilibrium transport, accounting for both the second-order and spontaneous Hall responses. These findings establish disordered WTe$ {_2}$ as a platform hosting Weyl-Kondo fermions and highlight disorder as an effective control knob for inducing correlated topological phases in weakly correlated Weyl semimetals.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Comments are welcome
Knotted DNA Configurations in Bacteriophage Capsids: A Liquid Crystal Theory Approach
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-15 20:00 EDT
Pei Liu, Zhijie Wang, Tamara Christiani, Mariel Vazquez, M. Carme Calderer, Javier Arsuaga
Bacteriophages, viruses that infect bacteria, store their micron long DNA inside an icosahedral capsid with a typical diameter of 40 nm to 100 nm. Consistent with experimental observations, such confinement conditions induce an arrangement of DNA that corresponds to a hexagonal chromonic liquid-crystalline phase, and increase the topological complexity of the genome in the form of knots. A mathematical model that implements a chromonic liquid-crystalline phase and that captures the changes in topology has been lacking. We adopt a mathematical model that represents the viral DNA as a pair of a vector field and a line. The vector field is a minimizer of the total Oseen-Frank energy for nematic liquid crystals under chromonic constraints, while the line is identified with the tangent to the field at selected locations, representing the central axis of the DNA molecule. The fact that the Oseen-Frank functional assigns infinite energy to topological defects (point defects in two dimensions and line defects in three dimensions) precludes the presence of singularities and, in particular, of knot structures. To address this issue, we begin with the optimal vector field and helical line, and propose a new algorithm to introduce knots through stochastic perturbations associated with splay and twist deformations, modeled by means of a Langevin system. We conclude by comparing knot distributions generated by the model and by interpreting them in the context of previously published experimental results. Altogether, this work relies on the synergy of modeling, analysis and computation in the study of viral DNA organization in capsids.
Soft Condensed Matter (cond-mat.soft), Biomolecules (q-bio.BM)
Topological superconductivity in a dimerized Kitaev chain revealed by nonlocal transport
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-15 20:00 EDT
Rafael Pineda Medina, Pablo Burset, William J. Herrera
Artificial Kitaev chains engineered from semiconducting quantum dots coupled by superconducting segments offer a promising route to realize and control Majorana bound states for topological quantum computation. We study a dimerized Kitaev chain–equivalent to a superconducting Su-Schrieffer-Heeger model–and analyze the behavior of the resulting two coupled chains. We show that interference between Majorana edge modes from each chain gives rise to observable signatures in nonlocal conductance. Additionally, we identify a parity effect in the system length that governs the coupling of edge states, supported by an analytical model. Our results provide experimentally accessible probes for Majorana hybridization in mesoscopic topological superconductors.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Gradient-based search of quantum phases: discovering unconventional fractional Chern insulators
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-15 20:00 EDT
André Grossi Fonseca, Eric Wang, Sachin Vaidya, Patrick J. Ledwith, Ashvin Vishwanath, Marin Soljačić
The discovery and understanding of new quantum phases has time and again transformed both fundamental physics and technology, yet progress often relies on slow, intuition-based theoretical considerations or experimental serendipity. Here, we introduce a general gradient-based framework for targeted phase discovery. We define a differentiable function, dubbed “target-phase loss function”, which encodes spectral fingerprints of a quantum state, thereby recasting phase search as a tractable optimization problem in Hamiltonian space. The method is broadly applicable to phases characterized by ground-state degeneracy and can be extended to a wide range of symmetry-broken and topological orders. As a demonstration, we apply it to spinless fermions on the kagome lattice and discover two distinctive fractional Chern insulators (FCIs), verified through detailed exact diagonalization: (i) at filling $ \nu = 1/3$ , a “non-ideal” Abelian FCI whose band geometry lies far beyond the Landau-level mimicry paradigm and all recent generalizations; and (ii) at $ \nu = 1/2$ , a non-Abelian FCI stabilized purely by finite-range two-body interactions. These results provide the first explicit realization of such types of FCIs and establish a versatile paradigm for systematic quantum-phase discovery.
Strongly Correlated Electrons (cond-mat.str-el)