CMP Journal 2025-09-30
Statistics
Nature Materials: 2
Nature Physics: 2
Physical Review Letters: 22
Physical Review X: 1
arXiv: 112
Nature Materials
Intrinsic intermolecular photoinduced charge separation in organic radical semiconductors
Original Paper | Electronic and spintronic devices | 2025-09-29 20:00 EDT
Biwen Li, Petri Murto, Rituparno Chowdhury, Laura Brown, Yutong Han, Giacomo Londi, David Beljonne, Hugo Bronstein, Richard H. Friend
Organic radicals based on tris(2,4,6-trichlorophenyl)methyl (TTM) radicals show efficient photoluminescence from excitons in the spin-doublet manifold, but their potential in charge photogeneration remains unexplored. Here we report that when TTMs are in contact, photoexcitation generates TTM anion-TTM cation pairs. These can decay radiatively or be fully separated under an electric field bias. We use a triphenyl-substituted TTM (P3TTM) in which the phenyl end groups enhance intermolecular interactions. In dilute (5 wt%) films in a wide-energy-gap organic semiconductor host, we observe prompt photoluminescence from the excited radical at 645 nm, and a delayed component, beyond 1 μs, at 800 nm due to recombination of P3TTM anion-cation pairs. Measurements of photocurrent made with diode structures with 100% P3TTM showed close-to-unity charge collection efficiency in reverse bias. We have found ‘homojunction’ intermolecular charge separation, made possible when the extra energy for double occupancy of the non-bonding radical level on the anion is lower than the energy of the doublet exciton. This opens possibilities for light harvesting using single-material molecular semiconductors.
Electronic and spintronic devices, Electronic devices
Suppression of PCBM dimer formation in inverted perovskite solar cells
Original Paper | Electronic devices | 2025-09-29 20:00 EDT
Zheng Liang, Huifen Xu, Zhenda Huang, Xia Lei, Jiajiu Ye, Yong Zhang, Peide Zhu, Boyuan Liu, Wenjing Chen, Xue Wang, Yaru Li, Yunxiao Liao, Shirui Weng, Yuli Tao, Yalan Zhang, Hui Zhang, Feng Chen, Jie Zeng, Xiangbin Cai, Sang-Uk Lee, Jiufeng Dong, Wanting Liu, Hongmin Zhou, Hongzhen Lin, Liangbao Yang, Guoning Xu, Yong Ding, Jiang Sheng, Jingbai Li, Shangfeng Yang, Baomin Xu, Zhengguo Xiao, Thomas Kirchartz, Xu Pan, Nam-Gyu Park
Achieving a well-controlled electron-selective layer is critical for the device scalability and performance of perovskite solar cells. While phenyl-C61-butyric acid methyl ester (PCBM) is a promising electron-selective material in inverted perovskite solar cells, its dimerization under environmental stress accelerates the material degradation and complicates producing high-quality PCBM layers, thereby compromising device long-term operational stability and scale-up fabrication. Here we investigated the PCBM molecular stacking on perovskite surfaces, finding that the variability in perovskite surface termination leads to orientation and distribution heterogeneity of the PCBM layer, resulting in undesirable dimerization. To address this, we developed a molecular dopant for suppressing PCBM dimer formation, achieving a certified efficiency of 26.4% in laboratory-scale devices and 25.3% in 1 cm2 devices. Furthermore, these devices maintained 93% of their initial power conversion efficiency after 1,500 h of ageing at 85 °C following the ISOS L-2I protocol.
Electronic devices, Solar cells
Nature Physics
Gate-tunable double-dome superconductivity in twisted trilayer graphene
Original Paper | Condensed-matter physics | 2025-09-29 20:00 EDT
Zekang Zhou, Jin Jiang, Paritosh Karnatak, Ziwei Wang, Glenn Wagner, Kenji Watanabe, Takashi Taniguchi, Christian Schönenberger, S. A. Parameswaran, Steven H. Simon, Mitali Banerjee
Graphene moiré systems are ideal environments for investigating complex phase diagrams and gaining fundamental insights into the mechanisms that underlie them, as they permit controlled manipulation of electronic properties. Magic-angle twisted trilayer graphene has emerged as a key platform for exploring moiré superconductivity due to the robustness of its superconducting order and the ability to tune its energy bands with an electric field. Here we report the direct observation of two domes of superconductivity in the phase diagram of magic-angle twisted trilayer graphene. The dependence of the superconductivity of doped holes on the temperature, magnetic field and bias current shows that it is suppressed near a specific filling of the moiré flat band, leading to a double dome in the phase diagram within a finite range of the displacement field. The transport properties are also indicative of a phase transition and the potentially distinct nature of superconductivity in the two domes. Hartree-Fock calculations incorporating mild strain yield an incommensurate Kekulé spiral state whose effective spin polarization peaks in the regime where superconductivity is suppressed in the experiments.
Condensed-matter physics, Superconducting properties and materials
Impact of low-energy spin fluctuations on the strange metal in a cuprate superconductor
Original Paper | Electronic properties and materials | 2025-09-29 20:00 EDT
D. J. Campbell, M. Frachet, V. Oliviero, T. Kurosawa, N. Momono, M. Oda, J. Chang, D. Vignolles, C. Proust, D. LeBoeuf
Strange metals–which exhibit unusual properties such as a resistivity that scales linearly with temperature–challenge our understanding of charge transport in metals. Here we investigate how the strange metal phase of La2-xSrxCuO4 is impacted by a field-induced glassy antiferromagnetic state. Using magnetic fields above 80 T, we discover a strong enhancement of the normal state magnetoresistance when entering the antiferromagnetic glass phase. We demonstrate that the spin glass causes insulating-like upturns in the resistivity inside the pseudogap phase, which resolves the origin of the crossover from metal to insulator. In addition, the strange metal phase appears at low temperatures over an extended range of magnetic fields where magnetic moments fluctuate and disappears when these moments freeze out. We conclude that the transport properties of the strange metal phase are closely linked to low-energy magnetic fluctuations that persist at the lowest temperatures.
Electronic properties and materials, Superconducting properties and materials
Physical Review Letters
Single-Ion Information Engine for Charging Quantum Battery
Article | Quantum Information, Science, and Technology | 2025-09-30 06:00 EDT
Jialiang Zhang, Pengfei Wang, Wentao Chen, Zhengyang Cai, Mu Qiao, Riling Li, Yingye Huang, Haonan Tian, Chuyang Luan, Hengchao Tu, Kaifeng Cui, Leilei Yan, Junhua Zhang, Jingning Zhang, Manhong Yung, and Kihwan Kim
Information engines produce mechanical work through measurement and adaptive control. For information engines, the principal challenge lies in how to store the generated work to the external load. Here, we report an experimental demonstration where quantized mechanical motion serves as a quantum bat…
Phys. Rev. Lett. 135, 140403 (2025)
Quantum Information, Science, and Technology
Probing Vector Chirality in the Early Universe
Article | Cosmology, Astrophysics, and Gravitation | 2025-09-30 06:00 EDT
Junsup Shim, Ue-Li Pen, Hao-Ran Yu, and Teppei Okumura
Cosmological simulations show that a left-right asymmetry in the early Universe could leave a mark in the distribution of galaxy rotations.
Phys. Rev. Lett. 135, 141002 (2025)
Cosmology, Astrophysics, and Gravitation
Resummation of Universal Tails in Gravitational Waveforms
Article | Cosmology, Astrophysics, and Gravitation | 2025-09-30 06:00 EDT
Mikhail M. Ivanov, Yue-Zhou Li, Julio Parra-Martinez, and Zihan Zhou
We present a formula for the universal anomalous scaling of the multipole moments of a generic gravitating source in classical general relativity. We derive this formula in two independent ways using effective field theory methods. First, we use the absorption of low-frequency gravitational waves by…
Phys. Rev. Lett. 135, 141401 (2025)
Cosmology, Astrophysics, and Gravitation
Boundary Criticality for the Gross-Neveu-Yukawa Models
Article | Particles and Fields | 2025-09-30 06:00 EDT
Huan Jiang, Yang Ge, and Shao-Kai Jian
We study the boundary criticality for the Gross-Neveu-Yukawa (GNY) models. Employing interacting Dirac fermions on a honeycomb lattice with armchair boundaries, we use determinant quantum Monte Carlo simulation to uncover rich boundary criticalities at the quantum phase transition to a charge densit…
Phys. Rev. Lett. 135, 141602 (2025)
Particles and Fields
Dark-Matter-Electron Detectors for Dark-Matter-Nucleon Interactions
Article | Particles and Fields | 2025-09-30 06:00 EDT
Sinéad M. Griffin, Guy Daniel Hadas, Yonit Hochberg, Katherine Inzani, and Benjamin V. Lehmann
In a seminal paper now a decade old, it was shown that dark-matter detectors geared at probing interactions with nucleons could also be used to probe dark-matter interactions with electrons. In this Letter, we show that new detector concepts designed to probe dark-matter-electron interactions at low…
Phys. Rev. Lett. 135, 141803 (2025)
Particles and Fields
No Time for Surface Charge: How Bulk Conductivity Hides Charge Patterns from Kelvin Probe Force Microscopy in Contact-Electrified Surfaces
Article | Condensed Matter and Materials | 2025-09-30 06:00 EDT
Felix Pertl, Isaac C. D. Lenton, Tobias Cramer, and Scott Waitukaitis
A new experiment on static electricity casts doubt on previous ones.
Phys. Rev. Lett. 135, 146202 (2025)
Condensed Matter and Materials
Characterizing the Multipartite Entanglement Structure of Non-Gaussian Continuous-Variable States with a Single Evolution Operator
Article | Quantum Information, Science, and Technology | 2025-09-29 06:00 EDT
Mingsheng Tian, Xiaoting Gao, Boxuan Jing, Fengxiao Sun, Matteo Fadel, Manuel Gessner, and Qiongyi He
Multipartite entanglement is an essential resource for quantum information tasks, but characterizing entanglement structures in continuous-variable systems remains challenging, especially in multimode non-Gaussian scenarios. In this Letter, we introduce an efficient method for detecting multipartite…
Phys. Rev. Lett. 135, 140201 (2025)
Quantum Information, Science, and Technology
Classical Non-Markovian Noise in Symmetry-Preserving Quantum Dynamics
Article | Quantum Information, Science, and Technology | 2025-09-29 06:00 EDT
William M. Watkins and Gregory Quiroz
In quantum dynamics, symmetries are vital for identifying and assessing conserved quantities that govern the evolution of a quantum system. When promoted to the open quantum system setting, dynamical symmetries can be negatively altered by system-environment interactions, thus, complicating their an…
Phys. Rev. Lett. 135, 140401 (2025)
Quantum Information, Science, and Technology
Critically Slow Hilbert-Space Ergodicity in Quantum Morphic Drives
Article | Quantum Information, Science, and Technology | 2025-09-29 06:00 EDT
Saúl Pilatowsky-Cameo, Soonwon Choi, and Wen Wei Ho
The maximum entropy principle is foundational for statistical analyses of complex dynamics. This principle has been challenged by the findings of a previous work [Phys. Rev. X 7, 031034 (2017)], where it was argued that a quantum system driven in time by a certain aperiodic sequence without any expl…
Phys. Rev. Lett. 135, 140402 (2025)
Quantum Information, Science, and Technology
Exponential Quantum Advantages for Practical Non-Hermitian Eigenproblems
Article | Quantum Information, Science, and Technology | 2025-09-29 06:00 EDT
Xiao-Ming Zhang, Yukun Zhang, Wenhao He, and Xiao Yuan
Non-Hermitian physics has emerged as a rich field of study, with applications ranging from -symmetry breaking and skin effects to non-Hermitian topological phase transitions. Yet most studies remain restricted to small-scale or classically tractable systems. While quantum computing has shown stron…
Phys. Rev. Lett. 135, 140601 (2025)
Quantum Information, Science, and Technology
Condensates, Crystals, and Renormalons in the Gross-Neveu Model at Finite Density
Article | Particles and Fields | 2025-09-29 06:00 EDT
Francesco Benini, Ohad Mamroud, Tomás Reis, and Marco Serone
We study the symmetric Gross-Neveu model at finite density in the presence of a chemical potential for a generic number of fermion fields. By combining perturbative quantum field theory, semiclassical large , and Bethe ansatz techniques, we show that at finite two new dynamical…
Phys. Rev. Lett. 135, 141601 (2025)
Particles and Fields
Most Stringent Bound on Electron Neutrino Mass Obtained with a Scalable Low-Temperature Microcalorimeter Array
Article | Particles and Fields | 2025-09-29 06:00 EDT
B. K. Alpert et al.
The HOLMES experiment demonstrates the capability of an approach that uses calorimetric measurement of electron capture decay of Ho by placing a stringent upper bound on the electron neutrino mass.
Phys. Rev. Lett. 135, 141801 (2025)
Particles and Fields
Higgs Self-Coupling at the Future Circular ${e}^{+}{e}^{-}$ Collider
Article | Particles and Fields | 2025-09-29 06:00 EDT
Victor Maura, Ben A. Stefanek, and Tevong You
Single Higgs production at FCC-ee probes the Higgs self-coupling at next-to-leading order (NLO). Extracting a bound requires a global analysis accounting for other possible new physics contributions up to NLO. We determine the FCC-ee sensitivity to Higgs self-coupling modifications within the st…
Phys. Rev. Lett. 135, 141802 (2025)
Particles and Fields
Precision Measurement of Net-Proton-Number Fluctuations in $\mathrm{Au}+\mathrm{Au}$ Collisions at RHIC
Article | Nuclear Physics | 2025-09-29 06:00 EDT
B. E. Aboona et al. (STAR Collaboration)
Experiments at the Relativistic Heavy Ion Collider give the first hints of a critical point in the hot quark-gluon "soup" that is thought to have pervaded the infant Universe.
Phys. Rev. Lett. 135, 142301 (2025)
Nuclear Physics
Observation of Two-Dimensional Branched Flow of Light
Article | Atomic, Molecular, and Optical Physics | 2025-09-29 06:00 EDT
Yan Liu, Ke Lin, Zhaoyu Liu, Jianwei Qin, Qidong Fu, Peng Wang, and Fangwei Ye
We present an experimental study on light propagation within a bulk material, wherein a controlled, weakly disordered, three-dimensional spatial fluctuation of the refractive index is induced. We find that the random, varying potential splits a broad wave into a stable, two-dimensional (2D) caustic …
Phys. Rev. Lett. 135, 143801 (2025)
Atomic, Molecular, and Optical Physics
Handedness Selection and Hysteresis of Chiral Orders in Crystals
Article | Condensed Matter and Materials | 2025-09-29 06:00 EDT
Mauro Fava, Aldo H. Romero, and Eric Bousquet
A phase transition can drive the spontaneous emergence of chiral orders in crystals below a critical temperature. However, selecting either a right- or a left-handed phase with the aid of electromagnetic fields is challenging, particularly when intrinsic polar and axial moments are lacking. In this …
Phys. Rev. Lett. 135, 146102 (2025)
Condensed Matter and Materials
Machine Learning the Energetics of Electrified Solid-Liquid Interfaces
Article | Condensed Matter and Materials | 2025-09-29 06:00 EDT
Nicolas Bergmann, Nicéphore Bonnet, Nicola Marzari, Karsten Reuter, and Nicolas G. Hörmann
A framework rooted in perturbation theory extends machine-learning interatomic potential approaches, capturing complex dynamics and energetics at electrified solid-liquid interfaces.
Phys. Rev. Lett. 135, 146201 (2025)
Condensed Matter and Materials
Exchange Interaction in an InSb Quantum Well Measured with Landau-Level Tunneling Spectroscopy
Article | Condensed Matter and Materials | 2025-09-29 06:00 EDT
S. K. Clowes, C. P. Allford, D. Shearer, G. V. Smith, R. Simmons, B. N. Murdin, U. Zeitler, and P. D. Buckle
We studied InSb quantum well devices using Landau-level tunneling spectroscopy through a three-terminal differential conductance technique. This method is similar to filled-state scanning tunneling microscopy but uses a stationary contact instead of a mobile tip to analyze the two-dimensional electr…
Phys. Rev. Lett. 135, 146301 (2025)
Condensed Matter and Materials
Multipolar Fermi Surface Deformations in ${\mathrm{Sr}}{2}{\mathrm{RuO}}{4}$ Probed by Resistivity and Sound Attenuation: A Window into Electron Viscosity and the Collision Operator
Article | Condensed Matter and Materials | 2025-09-29 06:00 EDT
Davis Thuillier, Sayak Ghosh, B. J. Ramshaw, and Thomas Scaffidi
Recent developments in electron hydrodynamics have demonstrated the importance of considering the full structure of the electron-electron scattering operator, which encodes a sequence of lifetimes, one for each component of the Fermi surface deformation in a multipolar expansion. In this context, th…
Phys. Rev. Lett. 135, 146302 (2025)
Condensed Matter and Materials
Spin Transport Revealed by Spin Quantum Geometry
Article | Condensed Matter and Materials | 2025-09-29 06:00 EDT
Longjun Xiang, Hao Jin, and Jian Wang
We present the framework of spin quantum geometry, which is fundamentally linked to the spin degree of freedom of Bloch electrons and incorporates both the spin quantum geometric tensor (QGT) and the recently introduced Zeeman QGT, to elucidate spin transport. We show that the spin and Zeeman QGTs, …
Phys. Rev. Lett. 135, 146303 (2025)
Condensed Matter and Materials
Memory Kernel Coupling Theory: Obtaining Time Correlation Function from Higher-Order Moments
Article | Polymers, Chemical Physics, Soft Matter, and Biological Physics | 2025-09-29 06:00 EDT
Wei Liu, Yu Su, Yao Wang, and Wenjie Dou
Dynamical observables can often be described by time correlation functions (TCFs). However, efficiently calculating TCFs for complex quantum systems is a significant challenge, which generally requires solving the full dynamics of the systems. This Letter presents the memory kernel coupling theory (…
Phys. Rev. Lett. 135, 148001 (2025)
Polymers, Chemical Physics, Soft Matter, and Biological Physics
Charging Dynamics of Electric Double-Layer Nanocapacitors in Mean Field
Article | Polymers, Chemical Physics, Soft Matter, and Biological Physics | 2025-09-29 06:00 EDT
Ivan Palaia, Adelchi J. Asta, Megh Dutta, Patrick B. Warren, Benjamin Rotenberg, and Emmanuel Trizac
An electric double-layer capacitor (EDLC) stores energy by modulating the spatial distribution of ions in the electrolytic solution that it contains. We determine the mean-field timescales for planar EDLC relaxation to equilibrium after a potential difference is applied. We tackle first the fully sy…
Phys. Rev. Lett. 135, 148002 (2025)
Polymers, Chemical Physics, Soft Matter, and Biological Physics
Physical Review X
Exciton Formation in Two-Dimensional Semiconductors
Article | | 2025-09-29 06:00 EDT
K. Mourzidis, V. Jindal, M. Glazov, A. Balocchi, C. Robert, D. Lagarde, P. Renucci, L. Lombez, T. Taniguchi, K. Watanabe, T. Amand, S. Francoeur, and X. Marie
Excitons in two-dimensional transition-metal dichalcogenide monolayers form through both geminate and bimolecular pathways, resolving a key debate and enabling new control over exciton properties for quantum applications.
Phys. Rev. X 15, 031078 (2025)
arXiv
Enduring mechanical memory from the constitutive response of elastically recoverable nanostructured materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
Abhishek Gupta, Bhanugoban Maheswaran, Nicholas Jaegersberg, Komal Chawla, Ramathasan Thevamaran
Mechanical memory and computing are gaining significant traction as means to augment traditional electronics for robust and energy efficient performance in extreme environments. However, progress has largely focused on bistable metamaterials, while traditional constitutive memory effects have been largely overlooked, primarily due to the absence of compelling experimental demonstrations in elastically recoverable materials. Here, we report constitutive return point memory (RPM) in elastically recoverable, vertically aligned carbon nanotube (VACNT) foams, analogous to magnetic hysteresis-based RPM utilized in hard drives. Unlike viscoelastic fading memory, VACNTs exhibit non-volatile memory arising from rate-independent nanoscale friction. We find that the interplay between RPM and frictional dissipation enables independent tunability of the VACNT dynamic modulus, allowing for both on-demand softening and stiffening. We leverage this property to experimentally demonstrate tunable wave speed in a VACNT array with rigid interlayers, paving the way for novel shock limiters, elastodynamic lensing, and wave-based analog mechanical computing.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph)
Direct Comparison of Static and Dynamic Measurements of Spin Generation in a Topological Insulator Thin Film
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
Vinay Sharma, Sharadh Jois, Ryan Van Haren, Gregory M. Stephen, M. Tomal Hossain, M. Benjamin Jungfleisch, Patrick J. Taylor, Aubrey T. Hanbicki, Adam L. Friedman
The competition between intrinsic spin-orbit physics, magnetic phenomena, and the quality of materials and interfaces governs the charge-to-spin conversion processes that are essential to the implementation of spintronic devices. Direct comparisons of spin parameters, which serve as metrics of device quality, obtained by different measurement techniques are scarce, leading to uncertainty regarding discrepancies and the reliability of the methods. Here, we directly compare the spin Hall coefficient ($ {\theta}{SH}$ ) in molecular beam epitaxy grown films of $ (Bi{1-x}Sb_{x}){2}Te{3-y}Se_{y}$ (BSTS, x = 0.58, y = 1) at room temperature using two complementary techniques: a static method using non-local voltage (NLV) measurements in BSTS Hall bars with DC charge current, and a dynamic method using spin-torque ferromagnetic resonance (ST-FMR) measurement in $ BSTS/Ni_{80}Fe_{20}$ heterostructures at GHz frequencies. We obtain comparable spin Hall coefficients in angular-dependent ST-FMR ($ {\theta}{SH}$ =$ 4.7\pm1.1$ ) and in NLV ($ {\theta}{SH}$ =$ 2.8\pm0.6$ ). The complex effects of ferromagnetic interfaces while determining spin Hall coefficients using static or dynamic techniques becomes evident by contrasting our results to literature.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
6 Figures and supplementary included at the bottom
Peculiarities of optical absorption spectra of NdFe$_3$(BO$_3$)$_4$ crystal in magnetically ordered state and at the transition to spiral magnetic phase
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-30 20:00 EDT
V.V. Slavin, I.S. Kachur, V.S. Kurnosov, V.G. Piryatinskaya
We study experimentally and theoretically optical absorption spectra of neodymium ferroborate in the temperature range $ 6-32$ K. We show that the temperature dependences of integral intensities of absorption lines demonstrate qualitatively different behavior for $ \sigma$ - and $ \pi$ -polarizations of the light. We suggest that this behavior may be caused by the appearance of a spiral magnetic structure in the compound under study. To describe the temperature dependences of lines intensities we propose a theoretical model which takes into account the Dzyaloshinskii-Moriya interaction between Nd$ ^{3+}$ and Fe$ ^{3+}$ ions.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci), Optics (physics.optics)
18 pages, 6 figures
Stability and Structure of Binary Metal Hydrides under Pressure, Electrochemical Potential and Combined Pressure-Electrochemistry
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
Mgcini Keith Phuthi, Pin-Wen Guan, Russell J. Hemley, Venkatasubramanian Viswanathan
Metal hydrides can be tuned to have a diverse range of properties and find applications in hydrogen storage and superconductivity. Finding methods to control the synthesis of hydrides can open up new pathways to unlock novel hydride compounds with desired properties. We introduced the idea of utilizing electrochemistry as an additional tuning knob and in this work, we study the synthesis of binary metal hydrides using high pressure, electrochemistry and combined pressure-electrochemistry. Using density functional theory calculations, we predict the phase diagrams of selected transition metal hydrides under combined pressure and electrochemical conditions and demonstrate that the approach agrees well with experimental observations for most phases. We use the phase diagrams to determine trends in the stability of binary metal hydrides of scandium, yttrium and lanthanum as well as discuss the hydrogen-metal charge transfer at different pressures. Furthermore, we predict a diverse range of vanadium and chromium hydrides that could potentially be synthesized using pressure electrochemistry. These predictions highlight the value of exploring pressure-electrochemistry as a pathway to novel hydride synthesis.
Materials Science (cond-mat.mtrl-sci)
Ultralow-Temperature Cryogenic Transmission Electron Microscopy Using a New Helium Flow Cryostat Stage
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-30 20:00 EDT
Young-Hoon Kim, Fehmi Sami Yasin, Na Yeon Kim, Max Birch, Xiuzhen Yu, Akiko Kikkawa, Yasujiro Taguchi, Jiaqiang Yan, Miaofang Chi
Advances in cryogenic electron microscopy have opened new avenues for probing quantum phenomena in correlated materials. This study reports the installation and performance of a new side-entry condenZero cryogenic cooling system for JEOL (Scanning) Transmission Electron Microscopes (S/TEM), utilizing compressed liquid helium (LHe) and designed for imaging and spectroscopy at ultra-low temperatures. The system includes an external dewar mounted on a vibration-damping stage and a pressurized, low-noise helium transfer line with a remotely controllable needle valve, ensuring stable and efficient LHe flow with minimal thermal and mechanical noise. Performance evaluation demonstrates a stable base temperature of 6.58 K measured using a Cernox bare chip sensor on the holder with temperature fluctuations within 0.04 K. Complementary in-situ electron energy-loss spectroscopy (EELS) via aluminum bulk plasmon analysis was used to measure the local specimen temperature and validate cryogenic operation during experiments. The integration of cryogenic cooling with other microscopy techniques, including electron diffraction and Lorentz TEM, was demonstrated by resolving charge density wave (CDW) transitions in NbSe2 using electron diffraction, and imaging nanometric magnetic skyrmions in MnSi via Lorentz TEM. This platform provides reliable cryogenic operation below 7 K, establishing a low-drift route for direct visualization of electronic and magnetic phase transformations in quantum materials.
Strongly Correlated Electrons (cond-mat.str-el), Instrumentation and Detectors (physics.ins-det), Quantum Physics (quant-ph)
23 pages for main text, 7 figures, 8 supporting figures
Unraveling the role of disorder in the electronic structure of high entropy alloys
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
Neeraj Bhatt, Deepali Sharma, Asif Ali, Kapil Motla, Sonika Jangid, Ravi Prakash Singh, Ravi Shankar Singh
Disorder in high entropy alloys, arising from the random distribution of multiple elements, plays a crucial role in their novel properties desirable for various advanced engineering applications. We investigate the role of compositional and structural disorder on the electronic structure of osmium-based superconducting high entropy alloys, (Ru/Re)$ _{0.35}$ Os$ _{0.35}$ Mo$ _{0.10}$ W$ _{0.10}$ Zr$ _{0.10}$ , using photoemission spectroscopy and density functional theory (DFT). Elemental and cumulative core level shifts are found to be commensurate with elemental electronegativities and valence electron counts (VEC), respectively. Valence band spectra together with DFT results indicate that the crystal structure plays an important role in deciding the electronic structure of these high entropy alloys. Through temperature dependent high-resolution spectra, we unveil strongly suppressed spectral density of states (SDOS) in the close vicinity of Fermi level. Energy and temperature dependence of the SDOS in accordance with Altshuler-Aronov theory confirms localization of charge carriers in the presence of strong intrinsic disorder. Computed electron-phonon coupling strength and superconducting transition temperature aligning reasonably well with experiments further shed light on phonon-mediated pairing mechanism and role of disorder in these systems. Our results provide a way forward to the understanding of superconducting high entropy alloys through strategic control of disorder, VEC and crystal structure.
Materials Science (cond-mat.mtrl-sci), Disordered Systems and Neural Networks (cond-mat.dis-nn), Superconductivity (cond-mat.supr-con)
Phys. Rev. Materials 9, L092001 (2025)
Stacking-Controlled Magnetic Exchange and Magnetoelectric Coupling in Bilayer CrI$_2$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
B. Valdés-Toro, I. Ferreira-Araya, R. A. Gallardo, J. W. González
We use a first-principles calculations approach to reveal the electronic and magnetic properties of chromium diiodide (CrI$ _2$ ) bilayers and establish a hierarchy of magnetic interactions across stable registries. The monolayer presents a x-stripe antiferromagnetic ground state, while in bilayers the BA$ ^\prime$ stacking is the global minimum with antiparallel interlayer magnetic alignment. Bilayer configurations strengthen the exchange in the plane by 6 % to 10 %, while the exchange between layers is registry-dependent. The symmetry of each stacking configuration allows for anisotropic interactions. Dzyaloshinskii-Moriya terms appear in structures without inversion symmetry, which in this case also generates in-plane polarizations of up to $ \sim$ 10 $ \mu$ C/cm$ ^2$ , resulting in direct magnetoelectric coupling that is absent in centrosymmetric monolayers. Thus, stacking acts both as a selector of exchange anisotropy and as a driver of magnetoelectricity. Our results show that bilayer CrI$ _2$ can be mechanically reconfigured through interlayer sliding, with energy differences between stacking orders (25-50 meV/f.u.) that are compatible with experimental actuation. Tunable magnetism and register-dependent polarization offer promising opportunities for novel spintronic devices, where structural transitions can affect both magnetic states and electric dipoles.
Materials Science (cond-mat.mtrl-sci)
12 pages, 10 figures
Theoretical investigation on the formation of ethylene on a gold surface
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
Tim Schrader, Alen Shaji, Christin David, Eva Perlt
The targeted and efficient CO2 reduction remains an appealing option to capture CO2 from the atmosphere and transform it into value-added chemicals. The formation of methylene and subsequent dimerization to ethylene is one possible step in the rather complex pathway. These reactions typically occur on (catalytic) surfaces. It is therefore critical to gain a deeper understanding of the role of the surface. We study the reaction pathway of the dimerization on gold surfaces with varying layer thickness. The presence of support layers has a significant influence on the reaction coordinate, the energetic profile and finally on the adsorption energy of the product on the surface with interesting consequences for the role of nanostructured gold surfaces for CO2 upconversion.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
Non-Altermagnetic Origin of Exchange Bias Behaviors in Incoherent RuO$_2$/Fe Bilayer Heterostructures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
Shelby S. Fields, Joseph C. Prestigiacomo, Cory D. Cress, Nicholas G. Combs, Olaf van ‘t Erve, Patrick G. Callahan, Keith E. Knipling, Michelle E. Jamer, Frank M. Abel, Feng Ye, Arianna Minelli, Zachary J. Morgan, Haile Ambaye, Masaaki Matsuda, Avishek Maity, Valeria Lauter, Steven P. Bennett
Initially identified as a promising altermagnetic (AM) candidate, rutile RuO$ _2$ has since become embroiled in controversy due to contradictory findings of modeling and measurements of the magnetic properties of bulk crystals and thin films. For example, despite observations of a bulk non-magnetic state using density functional theory, neutron scattering, and muon spin resonance measurements, patterned RuO$ _2$ Hall bars and film heterostructures display magnetotransport signatures of magnetic ordering. Among the characteristics routinely cited as evidence for AM is the observation of exchange bias (EB) in an intimately contacted Fe-based ferromagnetic (FM) layer, which can arise due to interfacial coupling with a compensated antiferromagnet. Within this work, the origins of this EB coupling in Ru-capped RuO$ _2$ /Fe bilayers are investigated using polarized neutron diffraction, polarized neutron reflectometry, cross-sectional transmission electron microscopy, and super conducting quantum interference device measurements. These experiments reveal that the EB behavior is driven by the formation of an iron oxide interlayer containing Fe$ _3$ O$ _4$ that undergoes a magnetic transition and pins interfacial moments within Fe at low temperature. These findings are confirmed by comparable measurements of Ni-based heterostructures, which do not display EB coupling, as well as magnetometry of additional Fe/Ru bilayers that display oxide-driven EB coupling despite the absence of the epitaxial RuO$ _2$ layer. While these results do not directly refute the possibility of AM ordering in RuO$ _2$ thin films, they reveal that EB, and related magnetotransport phenomena, cannot alone be considered evidence of this characteristic in the rutile structure due to interfacial chemical disorder.
Materials Science (cond-mat.mtrl-sci)
20 pages, 7 figures
Stability and Superconductivity of Ternary Polyhydrides
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-30 20:00 EDT
Dmitrii V. Semenok, Di Zhou, Wuhao Chen, Alexander G. Kvashnin, Andrey V. Sadakov, Toni Helm, Pedro N. Ferreira, Christoph Heil, Vladimir M. Pudalov, Ivan A. Troyan, Viktor V. Struzhkin
We review five years of experimental and theoretical attempts (2020-2025) to enhance the superconducting critical temperature ($ \textit{T$ _c$ }$ ) of hydrogen-rich compounds by alloying binary superhydrides with additional elements. Despite predictions of higher $ \textit{T$ _c$ }$ in ternary systems such as La-Y-H, La-Ce-H, and Ca-Mg-H, experiments consistently show that the maximum $ \textit{T$ _c$ }$ in disordered ternary superhydrides does not exceed that of the best binary parent hydrides within experimental uncertainty. Instead, alloying primarily stabilizes high-symmetry polyhydride phases at lower pressures, enabling $ \textit{T$ _c$ }$ = 200 K near 110-120 GPa, while also improving vortex pinning and upper critical fields. Magnetic dopants suppress $ \textit{T$ _c$ }$ , whereas nonmagnetic additives leave it nearly unchanged, reminiscent of Anderson’s theorem. These findings indicate that alloying is unlikely to raise $ \textit{T$ _c$ }$ , but can reduce the pressures required to stabilize high-$ \textit{T$ _c$ }$ phases. We propose that fully ordered ternary hydrides, synthesized via controlled hydrogenation of intermetallic precursors, offer a promising route toward this goal.
Superconductivity (cond-mat.supr-con)
Robust quantum Hall resistance standard from uniform wafer-scale epitaxial graphene on SiC
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-30 20:00 EDT
François Couëdo, Chiara Mastropasqua, Aurélien Theret, Dominique Mailly, Adrien Michon, Mathieu Taupin
We report high-precision resistance measurements on quantum Hall resistance devices fabricated from uniform epitaxial graphene grown by propane-hydrogen chemical vapor deposition on a two-inch silicon carbide substrate. Through molecular doping, we achieve a low carrier density regime ($ n_\mathrm s < $ 1.5 \textperiodcentered 10$ ^{11}$ cm$ ^{-2}$ ) combined with high mobility ($ \upmu \geq$ 6000 cm$ ^2$ V$ ^{-1}$ s$ ^{-1}$ ) at low temperature. Accurate quantization of the Hall resistance is demonstrated at magnetic flux densities as low as 3.5 T, temperatures up to 8 K, and measurement currents up to 325 $ \upmu$ A, with relative measurement uncertainties of a few parts per billion. A stability diagram mapping dissipation as a function of temperature and current provides insight into optimal doping conditions that maximize the breakdown current. All measurements were carried out in a pulse-tube-based cryomagnetic system, enabling simplified and continuous operation of the quantum Hall resistance standard without liquid helium consumption.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph)
Transporting Baguettes With Minimal Action: The Geometry of Optimal Nonequilibrium Processes in Stochastic Thermodynamics
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-30 20:00 EDT
What are the fundamental limitations placed by the laws of thermodynamics on the energy expenditure needed to carry out a given task in a nonequilibrium environment in finite time? In this thesis, we investigate “optimal nonequilibrium processes”: how nonequilibrium state changes in a thermodynamic system may be performed most efficiently, in the sense of requiring the least amount of thermodynamic work. Surprisingly, there is a hidden, fundamental geometric structure in this optimization problem that is related to the mathematics of optimal transport theory: how to optimally send, e.g., baguettes from bakeries to cafés, given supply and demand constraints, that requires the least amount of total distance traveled by the baguettes. After giving a brief overview on the mathematical framework of stochastic thermodynamics for the overdamped Langevin equation, we present a trio of works: (1) applying optimal control theory to the Fokker-Planck equation to calculate exact optimal protocols for low-dimensional systems, which reproduces the intriguing previously-discovered discontinuities in globally optimal protocols and reveals new non-monotonic optimal protocols for a certain system; (2) exploiting the importance sampling of Langevin trajectories under different protocols, to adaptively optimize protocols by controlling the thermodynamic state trajectory, which is useful for efficiently calculating free energy differences between different Hamiltonians; and finally, (3) deriving an exact geometric description of optimal nonequilibrium processes and a geodesic-counterdiabatic decomposition for the optimal protocols that enact them, which satisfyingly explains the highly non-intuitive properties of discontinuities and possible non-monotonicity in globally optimal protocols.
Statistical Mechanics (cond-mat.stat-mech)
PhD thesis
Tunneling spectroscopy of two-dimensional superconductors with the quantum twisting microscope
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-30 20:00 EDT
Nemin Wei, Felix von Oppen, Leonid I. Glazman
The ongoing discoveries of graphene-based superconductors underscore the quest to understand the structure of new superconducting orders. We develop a theory that facilitates the use of the quantum twisting microscope (QTM) for that purpose. This work investigates momentum-conserving tunneling across a planar junction formed by a normal monolayer graphene tip and a superconducting graphene sample within the QTM setting. We show that the bias dependence of the zero-temperature tunneling conductance exhibits singularities that provide momentum-resolved information about the Bogoliubov quasiparticle spectra, including the superconducting gap. Using a model of superconducting twisted bilayer graphene (TBG), we illustrate that simultaneously tuning the tip doping level and the tip-sample twist angle allows for measuring the momentum-resolved superconducting gap in TBG. Our results indicate that momentum-conserving tunneling spectroscopy with the QTM is a promising method for exploring superconductivity in two-dimensional van der Waals materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
17 pages, 8 figures
Anti-hyperuniform Critical States of Active Topological Defects
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-30 20:00 EDT
Simon Guldager Andersen, Tianxiang Ma, Makito F. Katsume, Kexin Li, Xiao Liu, Martin Cramer Pedersen, Amin Doostmohammadi
Topological defects are fundamental to the collective dynamics of non-equilibrium systems and in active matter, mediating spontaneous flows, dynamic self-organization, and emergent pattern formation. Here, we reveal critical states in active nematics, marked by slowed defect density relaxation, amplified fluctuations, and heightened sensitivity to activity. Near criticality, defect interactions become long-ranged, scaling with system size, and the system enters an anti-hyperuniform regime with giant number fluctuations of topological defects and defect clustering. This transition reflects a dual scaling behavior: fluctuations are uniform at small scales but become anti-hyperuniform at larger scales, \tm{as supported by experimental measurements on large-field-of-view endothelial monolayers. We find that these anti-hyperuniform states with multiscale defect density fluctuations are robust to varying parameters, introducing frictional damping, and changing boundary conditions.} Finally, we show that the observed anti-hyperuniformity originates from defect clustering, distinguishing this transition from defect-unbinding or phase separation processes. Beyond fundamental implications for non-equilibrium systems, these results may inform biological contexts where topological defects are integral to processes such as morphogenesis and collective cellular self-organization.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech), Adaptation and Self-Organizing Systems (nlin.AO), Biological Physics (physics.bio-ph), Computational Physics (physics.comp-ph)
This is the Accepted Manuscript version of an article accepted for publication in Reports on Progress in Physics. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it
Why and when merging surface nanobubbles jump
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-30 20:00 EDT
Yixin Zhang, Xiangyu Zhang, Detlef Lohse
Gas bubble accumulation on substrates reduces the efficiency of many physicochemical processes, such as water electrolysis. For microbubbles, where buoyancy is negligible, coalescence-induced jumping driven by the release of surface energy provides an efficient pathway for their early detachment. At the nanoscale, however, gas compressibility breaks volume conservation during coalescence, suppressing surface energy release and seemingly disabling this detachment route. Using molecular dynamics simulations, continuum numerical simulations, and theoretical analysis, we show that surface nanobubbles with sufficiently large contact angles can nevertheless detach after coalescence. In this regime, detachment is powered by the release of pressure energy associated with nanobubble volume expansion. This finding thus establishes a unified driving mechanism for coalescence-induced bubble detachment across all length scales.
Soft Condensed Matter (cond-mat.soft), Fluid Dynamics (physics.flu-dyn)
Magnetotransport in a 2D Hybrid Band System: Dirac and Heavy Hole Interplay
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-30 20:00 EDT
G. M. Gusev, A. D. Levin, V. A. Chitta, Z. D. Kvon, N. N. Mikhailov
We investigate magnetoresistivity and the Hall effect in a 6.3 nm gapless HgTe quantum well - a two-dimensional hybrid band system featuring coexisting linear (Dirac-like) and parabolic hole energy bands at low energies. Using a classical two-subband model that incorporates intervalley scattering, we reveal a striking tenfold enhancement of the Hall resistance, primarily driven by the dominant transport contribution of Dirac holes. A comprehensive magnetotransport analysis enables us to extract key parameters, such as the mobilities of both carrier types, thereby providing insight into their complex interplay. These results establish the HgTe quantum well as a distinctive platform for exploring novel transport phenomena in hybrid band systems and deepen our understanding of mixed-carrier magnetotransport.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
9 pages, 6 figures
Phys. Rev. B 112, 125304 (2025)
Augmenting knee biomechanics through programmable knitted ExoSkin orthoses
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-30 20:00 EDT
Krishma Singal, Samuel P. Kirschner, Andrew K. Schulz, Emily D. Sanders, Gregory Sawicki, Kinsey R. Herrin, Elisabetta A. Matsumoto
A large subset of the population suffers injury or disease that causes knee pain and difficulty navigating day-to-day tasks. Off-the-shelf knee orthoses that are commonly used to treat these ailments overlook user-specific joint geometry and/or biomechanical needs. They can often be made with materials that lead to discomfort. We explore how the rich programmability of knitted fabrics can be harnessed to augment human biomechanics while promoting comfort. In this pursuit, we define \emph{ExoSkins}, a class of unpowered exoskeletons that are lightweight, comfortable, garment-like devices, and are designed based on user- and joint-specific needs. Although we foresee an expansive space for ExoSkin design (e.g., containing active materials, with sensing capabilities), in this study we focus on the interplay between knit geometry and programmable elasticity in passive orthoses as a means to augment the knee’s rotational stiffness. We design geometrically-programmed ExoSkins, abbreviated \emph{G-PExos}, that capitalize on the anisotropies of four types of knitted fabric to provide high stiffness for joint torque without the need for rigid materials. Our findings indicate that G-PExos can achieve rotational stiffness of similar magnitude to off-the-shelf orthoses and can also be tuned to achieve a much broader range of rotational stiffness without sacrificing comfort to the user.
Soft Condensed Matter (cond-mat.soft)
16 pages 5 figures in the main text; 8 pages, 7 figures in supplementary methods
Monte Carlo Diagonalization for Hubbard Model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-30 20:00 EDT
The Hubbard model has often been studied with exact diagonalization (ED). This impurity solver is fundamentally limited by the exponential scaling of the Fock space. To address this problem, we introduce Monte Carlo diagonalization. Using a truncated Fock space constructed with a Monte Carlo approach, we reduce the size of the basis required to represent the Hamiltonian. We can then apply the Lanczos and band Lanczos algorithms in this truncated basis to find the ground state and the Green function. This results in a significant economy of resources and the capacity to break the $ \sim$ 20-site limit of ED. Our results suggest that there is a threshold on the number of states needed to capture the physics. This allows us to reach clusters of size up to 32 sites and reproduce the expected physics.
Strongly Correlated Electrons (cond-mat.str-el)
9 pages, 7 figures
Sachdev-Ye-Kitaev Model in a Quantum Glassy Landscape
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-09-30 20:00 EDT
Surajit Bera, Jorge Kurchan, Marco Schiro
We study a generalization of `Yukawa models’ in which Majorana fermions, interacting via all-to-all random couplings as in the Sachdev-Ye-Kitaev (SYK) model, are parametrically coupled to disordered bosonic degrees of freedom described by a quantum $ p-$ spin model. The latter has its own non-trivial dynamics leading to quantum paramagnetic (or liquid) and glassy phases. At low temperatures, this setup results in SYK behavior within each metastable state of a rugged bosonic free energy landscape, the effective fermionic couplings being different for each metastable state. We show that the boson-fermion coupling enhances the stability of the quantum spin-glass phase and strongly modifies the imaginary-time Green’s functions of both sets of degrees of freedom. In particular, in the quantum spin glass phase, the imaginary-time dynamics is turned from a fast exponential decay characteristic of a gapped phase into a much slower dynamics. In the quantum paramagnetic phase, on the other hand, the fermions’ imaginary-time dynamics get strongly modified and the critical SYK behavior is washed away.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech), Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
19 pages, 9 Figures including Appendices
Machine Learning Based Optical Thermometry Using Photoluminescence and Raman Spectra of Diamonds Containing SiV Centers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
Md Shakhawath Hossain, Dylan G. Stone, Dale Landry, Xiaoxue Xu, Carlo Bradac, Toan Trong Tran
Micro- and nanothermometry enable precise temperature monitoring and control at the micro- and nanoscale, and have become essential diagnostic tools in applications ranging from high-power microelectronics to biosensing and nanomedicine. Most existing techniques rely on secondary micro- and nanothermometers that require individual calibration of each sensor, ideally both off- and in-situ, before use. We present an alternative approach that overcomes this limitation by employing fluorescent diamonds containing silicon-vacancy centers, where the thermo-sensitive physical quantities are the centers’ photoluminescence and the diamond host’s Raman signals. The photoluminescence and Raman data are analyzed using two multi-feature regression algorithms that leverage a minimal number of calibration diamonds and temperature set points to predict the temperature of previously unseen diamonds. Using this approach, the models achieve accuracies as low as 0.7 K, resolutions down to 0.6 K Hz$ ^{-1/2}$ , and sensitivity as high as 0.04 K$ ^{-1}$ . These correspond to improvements of roughly 70 percent (over threefold) in accuracy, 50 percent (twofold) in resolution, and 567 percent (sevenfold) in sensitivity compared with traditional single-feature models. Our approach is particularly suited to applications where pre-deployment calibration of every thermosensor is impractical, and it is generalizable to any thermometry platform with two or more simultaneously measurable temperature-dependent observables.
Materials Science (cond-mat.mtrl-sci), Optics (physics.optics)
Advancing Quantum Many-Body GW Calculations on Exascale Supercomputing Platforms
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
Benran Zhang, Daniel Weinberg, Chih-En Hsu, Aaron R. Altman, Yuming Shi, James B. White III, Derek Vigil-Fowler, Steven G. Louie, Jack R. Deslippe, Felipe H. da Jornada, Zhenglu Li, Mauro Del Ben
Advanced ab initio materials simulations face growing challenges as increasing systems and phenomena complexity requires higher accuracy, driving up computational demands. Quantum many-body GW methods are state-of-the-art for treating electronic excited states and couplings but often hindered due to the costly numerical complexity. Here, we present innovative implementations of advanced GW methods within the BerkeleyGW package, enabling large-scale simulations on Frontier and Aurora exascale platforms. Our approach demonstrates exceptional versatility for complex heterogeneous systems with up to 17,574 atoms, along with achieving true performance portability across GPU architectures. We demonstrate excellent strong and weak scaling to thousands of nodes, reaching double-precision core-kernel performance of 1.069 ExaFLOP/s on Frontier (9,408 nodes) and 707.52 PetaFLOP/s on Aurora (9,600 nodes), corresponding to 59.45% and 48.79% of peak, respectively. Our work demonstrates a breakthrough in utilizing exascale computing for quantum materials simulations, delivering unprecedented predictive capabilities for rational designs of future quantum technologies.
Materials Science (cond-mat.mtrl-sci)
Hund’s physics extends to actinide f electron systems
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-30 20:00 EDT
Byungkyun Kang, Roy N. Herrera-Navarro, Stephen S. Micklo, Mark R. Pederson, Eunja Kim
Uranium 5f electrons often yield heavy-fermion behavior via Kondo screening. However, the pronounced bad-metallic transport of uranium mononitride (UN) defies an incoherent Kondo explanation. Using density-functional theory combined with dynamical mean-field theory, we show that UN is a strongly correlated bad metal. The dominant correlations arise from intra-atomic Hund’s exchange interaction between two 5f electrons, which aligns local magnetic moments and produces large quasiparticle mass renormalization. This identifies UN as a 5f-electron analogue of a Hund’s metal-a paradigm chiefly associated with transition-metal d systems. Our results motivate a re-examination of the interplay between Mott, Kondo, and Hund-driven correlations across actinide correlated materials.
Strongly Correlated Electrons (cond-mat.str-el)
Correlative 3D Mapping of Structure, Composition, and Valence State Dynamics in Battery Cathodes via Simultaneous ADF-EDS-EELS Tomography
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
Jaewhan Oh, Sunggu Kim, Chaehwa Jeong, Jason Manassa, Jonathan Schwartz, Sangmoon Yoon, Robert Hovden, Hye Ryung Byon, Yongsoo Yang
Understanding degradation in battery cathodes and other functional materials requires simultaneous knowledge of structural, chemical, and electronic changes in three dimensions (3D). Here, we present a simultaneous ADF-EDS-EELS tomography method that enables 3D mapping of atomic structure, composition, valence states, and transition metal inhomogeneity within a single, low-dose STEM tilt series acquisition. Applied to LiNi1/3Co1/3Mn1/3O2 (NCM111) particles at different electrochemical cycling stages, this method reveals nanoscale degradation processes with full spatial correlation. We observe that while chemical composition evolves uniformly throughout the entire primary particle, valence state changes and transition metal segregation are strongly depth-dependent and concentrated near the surface. This coexistence of bulk and surface-driven degradation dynamics reveals distinct mechanisms acting at different spatial scales. The evolution of inhomogeneity and valence states deviates from simple phase transition models, highlighting the roles of ion migration and dissolution-driven segregation. Our findings establish valence state gradients and nanoscale inhomogeneity as active contributors to cathode failure. More broadly, this correlative 3D platform opens new opportunities for studying redox-driven transformations in fields such as neuromorphic computing and heterogeneous catalysis, where composition-structure-function coupling is inherently three-dimensional.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph), Chemical Physics (physics.chem-ph)
42 pages, 4 main figures, 12 supplementary figures
Delocalization Induced by Enhanced Hyperuniformity in One-Dimensional Disordered Systems
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-09-30 20:00 EDT
Junmo Jeon, Harukuni Ikeda, Shiro Sakai
In one dimension, any disorder is traditionally believed to localize all states. We show that this paradigm breaks down under hyperuniform disorder, which suppresses long-wavelength fluctuations and interpolates between random and periodic potentials. In tight-binding chains, strong hyperuniformity induces a sharp delocalization transition and the emergence of mobility edges. The transition is identified by the generalized fractal dimension and corroborated by the scaling of localization length and transmittance. Hyperuniform disorder thus provides a general mechanism for engineering mobility edges and controlling transport in low dimensions.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
12 pages, 9 figures
Evanescent-mode-assisted Klein tunneling in dual-gated bilayer graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-30 20:00 EDT
We theoretically investigate the electron tunneling in dual-gated bilayer graphene-based $ n/p$ junctions. It is shown that a band gap is introduced by tuning the gate voltage, which modifies the pseudospin polarization and breaks anti-Klein tunneling at normal incidence. Specifically, when the pseudospin polarization vectors for the propagating and evanescent wave modes on the left and right regions of the junction are orthogonal, a revival of Klein tunneling is achieved. The Berry phase associated with Klein tunneling in dual-gated bilayer graphene is not limited to $ \pi$ but varies with the junction parameters. Furthermore, the Klein tunneling is accompanied by a $ \pi$ jump in the reflection phase around the normal incidence.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Noncollinear Magnetic Multipoles in Collinear Altermagnets
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
Luca Buiarelli, Rafael M. Fernandes, Turan Birol
Altermagnets host an array of magnetic multipoles, which are often visualized and studied in the reciprocal space. In the real space, the relative phase of the multipoles of the spin-density around atoms determines whether a system is an altermagnet or a conventional antiferromagnet. In this study, we approach these real space multipoles in altermagnets using a combination of first principles calculations and group theory. We show that even in collinear magnets, the local spin density is necessarily noncollinear due to spin-orbit coupling. Moreover, the noncollinear contributions often provide a more direct illustration of the magnetic multipolar character of altermagnetism than the collinear contribution, which is dominated by the dipolar term. Our first principles calculations also show that 32-poles, in addition to the octupoles, can be visible in spin-density of d-wave altermagnets, and they must be taken into account in discussions of the macroscopic response. Finally, we elucidate the interplay between magnetism and subtle crystal structural distortions in perovskite altermagnets, which provide a fertile playground for studying phase transitions between antiferromagnetic and altermagnetic phases.
Materials Science (cond-mat.mtrl-sci)
7 pages, 4 figures
Superconductivity at 22.3 K in Compressed Sodium-intercalated Graphite
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-30 20:00 EDT
Ming-Xing Huang, Yuan-Qing Liu, Chun-Mei Hao, Xi Shao, Tingwei An, Guochun Yang, Yufei Gao, Shaojie Wang, Lin Wang, Bo Xu, Feng Ke, Xiang-Feng Zhou, Yongjun Tian
Graphite intercalation compounds (GICs) have long been recognized as promising candidates for high-temperature superconductivity by intercalation or charge doping, yet experimental progress has stalled with transition temperatures (Tc) limited to 11.5 K at ambient pressure and 15.1 K at 7.5 GPa in calcium-intercalated graphite over decades. Here, we report robust superconductivity in sodium-intercalated graphite with Tc of 22.3 K, as demonstrated by clear zero-resistance behavior. Our approach involves simply room-temperature grinding of graphite with sodium, followed by slight compression up to 7.1 GPa, circumventing complex synthesis procedures. Through synchrotron X-ray diffraction combined with first-principles calculations, we identify the major superconducting phase as an orthorhombic stage-2 GIC structure with slightly over-stoichiometric composition (Na1+xC8). Electron-phonon coupling calculations reveal that superconductivity primarily emerges from the interactions between out-of-plane carbon electrons and low-frequency Na/C this http URL enhancement in Tc establishes sodium as superior for achieving higher-Tc in GICs and illustrates promising pathway for further optimization through compositional and structural tuning.
Superconductivity (cond-mat.supr-con)
Exploring Magnetic Phases in Dual-Species Mott insulating Spinor Lattice Gases
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-09-30 20:00 EDT
Rui-Shan Li, Zong-Zhen Pan, Shi-Jie Yang, Yi Zheng
We explore the Mott insulating phases of dual-species bosonic spinor lattice gases, emphasizing the intriguing interplay between synthetic flux and inter-species spin exchange interaction. One of the species is subjected to Raman assisted tunneling, which leads to a synthetic flux within the framework of synthetic dimensions. In the deep Mott regime, the low energy physics is governed by an unconventional and highly tunable spin model, which is characterized by two distinct spin chains. The synthetic flux serves as an effective spin-orbit coupling, inducing Dzyaloshinskii-Moriya interactions in one of the spin chains. The inter-species spin exchange interaction gives rise to the inter-chain coupling embodied as an isotropic XX interaction. Using time-evolving block decimation method for tensor network states, we compute order parameters, correlation functions and structure factors to identify the ground state magnetic phases. The DM interaction in one species, when combined with the inter-species spin-exchange interaction, can induce spiral magnetic order in the second, otherwise non-chiral species. Besides, the interplay of a transverse field applied to one spin chain and the inter-species coupling can drive both spin chains into a paramagnetic phase simultaneously. These results reveal that inter-species coupling serves as a powerful conduit for transmitting magnetic correlations, enabling exotic phases beyond the single-component perspective.
Quantum Gases (cond-mat.quant-gas)
8 pages, 7 figures
Nonreciprocal interactions induce persistent active clusters in binary colloids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-30 20:00 EDT
Shoma Hara, Masazumi Okada, Keisuke Kittaka, Sho Tanami, Yuichi Iwasaki, Hiroaki Ishikawa, Kiwamu Yoshii, Yutaka Sumino
We study binary colloids under AC electric fields, where electrohydrodynamic (EHD) flows generate nonreciprocal interactions. Mixing particles of different sizes produces self-propelled pairs that fragment and reassemble into persistent active clusters, unlike the static crystallization of single-sized systems. Agent-based and continuum models reproduce these dynamics and identify two key mechanisms: asymmetric pair propulsion and spray-like fission from excluded-volume polarity. These results establish a minimal, controllable platform for exploring nonreciprocal active matter and highlight nonreciprocity as a general route to engineer reconfigurable colloidal assemblies.
Soft Condensed Matter (cond-mat.soft), Pattern Formation and Solitons (nlin.PS)
12 pages, 6 figures
Non-Hermitian topological superconductivity with symmetry-enriched spectral and eigenstate features
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-30 20:00 EDT
Chuo-Kai Chang, Kazuma Saito, Nobuyuki Okuma, Hsien-Chung Kao, Chen-Hsuan Hsu
We investigate a one-dimensional superconducting lattice that realizes all internal symmetries permitted in non-Hermitian systems, characterized by nonreciprocal hopping, onsite dissipation, and $ s$ -wave singlet pairing in a Su-Schrieffer-Heeger-type structure. The combined presence of pseudo-Hermiticity and sublattice symmetry imposes constraints on the energy spectra. We identify parameter regimes featuring real spectra, purely imaginary spectra, complex flat bands, and Majorana zero modes, the latter emerging when a uniform transverse magnetic field suppresses the non-Hermitian skin effect. We show that a uniform onsite dissipation is essential for stabilizing the zero modes, whereas a purely staggered dissipation destroys the topological superconductivity. Through Hermitianization, we construct a spectral winding number as a topological invariant and demonstrate its correspondence with the gap closing conditions and appearance of the Majorana zero modes, allowing us to establish topological phase diagrams. Moreover, we reveal nontrivial correlations between the particle-hole and spin components of left and right eigenstates, enforced by chiral symmetry, pseudo-Hermiticity, and their combination. Our results highlight how non-Hermiticity, sublattice structure, and superconductivity together enrich symmetry properties and give rise to novel topological phenomena.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
23 pages, 19 figures
Thermally Activated Plasticity in Single-Crystal Titanium: A Molecular Dynamics Study of Nanoscale Deformation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
G. Markovic, F. J. Dominguez-Gutierrez
Hexagonal close-packed (hcp) titanium exhibits a complex temperature-dependent mechanical response that is central to its use in structural applications. We employ large-scale molecular dynamics simulations to investigate the nanoindentation behavior of single-crystalline a-Ti along the [0001], [10-10], and [2-110] orientations at 10, 300, and 600 K. The simulations reveal how temperature modifies the onset of plasticity and the subsequent evolution of dislocation activity, including nucleation, glide, and the competition between basal and pyramidal <c+a> slip. Schmid factor mapping establishes a direct correlation between the orientation-dependent activation of slip systems and the resolved shear stress fields beneath the indenter. The results demonstrate a pronounced increase in thermally assisted dislocation motion with temperature, which manifests as diffuse slip traces and less localized pile-up patterns. Surface morphologies obtained at 300 K are consistent with atomic force microscopy observations, validating the atomistic modeling approach. At elevated temperatures, enhanced dislocation recovery and redistribution of slip pathways dominate the indentation response, highlighting the role of thermal activation in controlling plasticity in hcp titanium.
Materials Science (cond-mat.mtrl-sci)
Selective nonthermal melting in phlogopite under ultrafast energy deposition
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
Phlogopite is a complex magnesium-rich mineral from the dark mica group, KMg$ _3$ (AlSi$ _3$ O$ _{10}$ )(OH)$ _2$ . Its response to ultrafast excitation of its electronic system is studied using a hybrid model that combines tight-binding molecular dynamics with transport Monte Carlo and the Boltzmann equation. Simulations predict that at the deposited dose of ~0.17 eV/atom (electronic temperature $ T_e$ ~11,000 K), the first hydrogens start to migrate in the otherwise preserved lattice, transiently turning mica into a superionic state. At the dose of ~0.4 eV/atom ($ T_e$ ~13,000 K), Mg atoms start to diffuse like a liquid within stable sublattices of other elements, suggesting a superionic-superionic phase transition. At a dose of approximately 0.5 eV/atom ($ T_e$ ~14,000 K), the entire atomic lattice destabilizes, disordering on picosecond timescale. It is accompanied by the formation of defect energy levels inside the bandgap. At the doses ~0.9 eV/atom ($ T_e$ ~16,000 K), the bandgap completely collapses, turning the material metallic (electronically conducting). At even higher doses, nonthermal acceleration of atoms heats the atomic system at ultrafast timescales; K and O elements are most affected, accelerating within a few tens of femtoseconds.
Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
Replication and Information Extraction in a Minimal Agent-Environment Model
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-09-30 20:00 EDT
Sebastiano Ariosto, Jerome Garnier-Brun, Luca Saglietti, Davide Straziota
We consider an unsupervised classifying agent that evolves by enforcing self-consistency of its labels under continual exposure to a data-generating environment. Because the agent’s predictions feed back into its own regularized updates, the dynamics can stabilize into self-sustaining modes of operation, which we coin functional replicators. Remarkably, such replicators can spontaneously align with the latent structure of the environment, despite never being exposed to ground-truth labels or selected for adaptation. Using analytical tools from statistical mechanics and numerical experiments, we show that the onset of this regime corresponds to a transition driven by weak correlations between the agent’s initial state and environmental structure. Extending the model to multiple agents, we find that their mutual influence can spontaneously break symmetry and produce consensus, illustrating a minimal setting for decentralized collective learning.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech), Adaptation and Self-Organizing Systems (nlin.AO)
Main: 6 pages, 3 figures. SM: 14 pages, 10 figures
Evidence of electronic instability driven structural distortion in the nodal line semimetal CoSn$_2$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
Suman Nandi, Bishal Maity, Shovan Dan, Khadiza Ali, Bikash Patra, Anshuman Mondal, Gaston Garbarino, Pierre Rodière, Sitaram Ramakrishnan, Bahadur Singh, Arumugam Thamizhavel
Understanding the mechanisms that drive spontaneous rotational symmetry breaking in correlated electron systems is a central challenge in condensed matter physics. Although such symmetry breaking phases have been studied in low-dimensional and strongly correlated materials, its emergence in structurally simpler compounds remains less explored. Here, we investigate non-magnetic CoSn$ 2$ that is a centrosymmetric intermetallic compound crystallizing in a tetragonal structure at ambient conditions, and discover an electronically driven symmetry breaking instability. Electrical resistivity reveals a distinct change in the slope below 25 K, deviating from the expected Bloch-Grüneisen behavior. This anomaly is attributed towards a structural change as at 22 K single crystal X-ray diffraction using synchrotron radiation uncovers weak superlattice reflections that leads to a doubling of $ \textbf{a}$ and $ \textbf{c}$ , resulting in a 4-fold superstructure. The symmetry of the lattice reduces from tetragonal to acentric monoclinic but without any discernible monoclinic distortion down to 10 K. This structural transition is accompanied by a twofold symmetry in angular magnetoresistance, contrasting the fourfold symmetry observed at higher temperatures. First-principles calculations show no phonon softening but reveal enhanced electronic susceptibility, suggesting an electronic instability. Polarization-dependent ARPES measurements further identify a strong orbital anisotropy dominated by the in-plane Co-$ d{xy}$ states. Collectively, our results point to an electronic instability driven structural distortion in CoSn$ _2$ , offering a rare platform to study symmetry breaking in a non-magnetic metallic system.
Materials Science (cond-mat.mtrl-sci)
A Non-Equilibrium Dissipation Parameter and the Ideal Glass
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-09-30 20:00 EDT
Jun-Ying Jiang, Liang Gao, Hai-Bin Yu
Glass materials, as quintessential non-equilibrium systems, exhibit properties such as energy dissipation that are highly sensitive to their preparation histories. A key challenge has been identifying a unified order parameter to rationalize these properties. Here, we demonstrate that a configurational distance metric can effectively collapse energy dissipation data across diverse preparation histories and testing protocols, including varying cooling rates, aging processes, probing times, and the amplitudes of mechanical excitation, as long as the temperature remains above the so-called ideal glass transition (where the extrapolated structural relaxation time diverges). Our results provide a unified description for the non-equilibrium dissipation and suggest that the putative concept of the ideal glass transition is imprinted in material characteristics
Disordered Systems and Neural Networks (cond-mat.dis-nn), Soft Condensed Matter (cond-mat.soft)
13 pages, 5 figures, pubilshed to Reports on Progress in Physics
Symmetric Lévy flights in semi-infinite domain
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-30 20:00 EDT
Barnali Pyne, Kiran M. Kolwankar
We study symmetric Lévy flights in a semi-infinite domain $ [0,\infty)$ with a reflecting and absorbing boundary at 0. To this end, we use the fractional differential equation that governs the Lévy process. Incorporating the boundary conditions in Lévy flights has been an open and tricky question, as the long jumps can lead to the Lévy flights leaping over the boundary. We, for the first time, incorporate reflecting and absorbing boundary conditions for Lévy flights and solve the fractional differential equation analytically to find the probability densities. Monte Carlo simulations are also performed for both boundary conditions to verify the results. Analytical and simulation results perfectly coincide for the reflecting boundary condition and, for the absorbing boundary condition, they coincide for the large abscissa values.
Statistical Mechanics (cond-mat.stat-mech)
Entanglement signatures of gapless topological phases in a $p$-wave superconductor
New Submission | Other Condensed Matter (cond-mat.other) | 2025-09-30 20:00 EDT
S. Srinidhi, Shashi C. L. Srivastava, Jayendra N. Bandyopadhyay
We explore the gapless topological phases of a $ p$ -wave superconductor, probing its rich topologically ordered phases and underlying quantum phenomena. The topological order of the system is characterized by studying its entanglement properties. This study confirms the bulk-boundary correspondence in the entanglement spectrum, even without a full bulk gap. For contractible bipartitions, the entanglement entropy varies non-monotonically with the chemical potential, displaying pronounced peaks at points where the bulk gap closes and reopens, signaling topological quantum phase transitions. This behavior remains robust in the thermodynamic limit. The entanglement entropy grows with system size for non-contractible bipartitions, indicating long-range entanglement in the gapless phase. These findings reveal the subtle interplay between symmetry, entanglement, and topology in gapless systems, and emphasize the role of entanglement-based diagnostics in identifying unconventional topological phases beyond the gapped paradigm.
Other Condensed Matter (cond-mat.other), Superconductivity (cond-mat.supr-con), Quantum Physics (quant-ph)
12 pages, 9 figures
Geometric Frustration Directs the Self-Assembly of Nanoparticles with Crystallized Ligand Bundles
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-30 20:00 EDT
Federico Tomazic, Aswathy Muttathukattil, Afshin Nabiyan, Felix Schacher, Michael Engel
Polymer-grafted nanoparticles are versatile building blocks that self-assemble into a rich diversity of mesostructures. Coarse-grained molecular simulations have commonly accompanied experiments by resolving structure formation pathways and predicting phase behavior. Past simulations represented nanoparticles as spheres and the ligands as flexible chains of beads, isotropically tethered to the nanoparticles. Here, we investigate a different minimal coarse-grained model. The model consists of an attractive rod tethered to a repulsive sphere. The motivation of this rod-sphere model is to describe nanospheres with a partially crystallized, stretched polymeric bundle, as well as other complex building blocks such as rigid surfactants and end-tethered nanorods. Varying the ratio of sphere size to rod radius stabilizes self-limited clusters and other mesostructures of reduced dimensionality. The complex phase behavior we observe is a consequence of geometric frustration.
Soft Condensed Matter (cond-mat.soft), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph), Chemical Physics (physics.chem-ph)
17 pages, 6 figures
J. Phys. Chem. B 128, 11258-11266 (2024)
Passive polymers in active turbulence undergo a collapse-stretch transition
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-30 20:00 EDT
Zahra K. Valei, Davide Marenduzzo, Tyler N. Shendruk
Active processes in living systems generate nonequilibrium forces that deform embedded passive macromolecules. To understand how such dynamics influence polymer conformation, we study a flexible passive chain in an active nematic fluid. Using hybrid simulations, we uncover a length-dependent transition in polymer behavior: long chains align with and stretch along defect-driven flows, while short chains bend and collapse due to localized stresses. These responses are controlled by a competition between the polymer size and the emergent length scale of the active turbulence. Our results reveal a defect-mediated mechanism for conformational control and point toward general physical principles for designing responsive soft materials that couple passive structure to active dynamics.
Soft Condensed Matter (cond-mat.soft)
Energetics and thermodynamics of bilayer rectangular artificial spin ices
New Submission | Other Condensed Matter (cond-mat.other) | 2025-09-30 20:00 EDT
Gabriel A. Oliveira (1), Winder A. Moura-Melo (1), Afranio R. Pereira (1), Fabio S. Nascimento (2) ((1) Departamento de Física, Universidade Federal de Viçosa, 36570-900, Viçosa, Minas Gerais, Brazil, (2) Centro de Formação de Professores, Universidade Federal do Recôncavo da Bahia, 45300-000, Amargosa, Bahia, Brazil)
Bilayer rectangular artificial spin ices (BRASIs) with distinct aspect ratios, $ \gamma$ , are considered. Namely, we investigate how the underlying geometry modifies the interaction between two rectangular artificial spin ice layers separated by a height offset, $ h$ , whenever compared to the square case. Actually, rectangular layers interact by means of a Buckingham-like potential, whereas in the square case, one has an algebraic (van der Walls-like) interaction. In addition, Moiré patterns for BRASIs are less definite than for the square bilayer. We also deal with their basic thermodynamics, showing the behavior of the specific heat as a function of temperature and $ \gamma$ for a number of height offsets.
Other Condensed Matter (cond-mat.other)
Splitting of electronic spectrum in paramagnetic phase of itinerant ferromagnets and altermagnets
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-30 20:00 EDT
We study self-energy effects, induced by strong magnetic fluctuations in paramagnetic phase of strongly-correlated itinerant magnets within the density functional theory combined with the dynamical mean field theory (DFT+DMFT approach) and its non-local extension. As concrete examples, we consider $ \alpha$ -iron, half metal CrO$ _2$ , van der Waals material CrTe$ _2$ , and altermagnet CrSb. We show that both local and non-local magnetic correlations yield splitting of the electronic spectrum in the paramagnetic phase, such that it closely resembles the DFT band structure in the ordered phase and suppresses spectral weight at the Fermi level. The relative importance of non-local vs. local correlations depends on the proximity to half filling of $ d$ states: closer to half filling, the role of local correlations increases. Although the obtained split bands do not possess a certain spin projection, their splitting suppresses spectral weight at the Fermi level. The obtained electronic states are also expected to be easily spin polarized by a weak external magnetic field.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
6+4 pages, 4+1 figures
Magnetic-field dependent vortex dynamics and critical currents in superconducting microwires with regular large-area perforation by pinholes
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-30 20:00 EDT
Dong Zhu, Ilya Charaev, Konstantin Ilin, Andreas Schilling
We report on results of simulations and experiments of vortex states in superconducting micro-wires with periodic rectangular pinhole structures. The simulations have been performed by means of numerically solving the time-dependent Ginzburg-Landau (TDGL) equations. With increasing bias current and for different values of the external magnetic field applied normal to the structure plane, we observe at first a vortex free Meissner state, followed by a resistive vortex-flow mixed state and a state with a more complex vortex pattern. The resulting dependence of the critical current Ic on magnetic field exhibits two plateaus with distinctly different vortex dynamics. Corresponding experimentally measured magnetic-field dependences of Ic of WSi microwires with periodic pinhole structures and varying hole spacing confirmed the predictions of these simulations, showing two ranges of magnetic field with almost field-independent critical currents. The experimentally determined critical currents are larger for a smaller pinhole spacing, in agreement with the results of the TDGL simulations. The good agreement of the simulations with the experimental results provides a convenient strategy for the optimization of single-photon detectors with or without artificial and natural defects.
Superconductivity (cond-mat.supr-con)
A DNA-encoded recipe to direct multi-stage colloidal assembly
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-30 20:00 EDT
Pepijn G. Moerman, Chenghung Chou, Thomas E. Videbæk, W. Benjamin Rogers, Rebecca Schulman
In equilibrium self-assembly, microscopic building blocks spontaneously self-organize into stable structures as dictated by their interaction potentials, which limits the accessible structural features to those that correspond to global minima in free energy landscapes; they are often ordered and periodic on length scales comparable to the building block size. Coupling the assembly process to an exergonic reaction drives the system out of equilibrium so that an assembly pathway can be engineered to target a specific kinetically stabilized state, which in principle opens up a vast design space with access to diverse complex structures with features on multiple length scales. However, the question of how such features might be specifically targeted remains unanswered. Here, we explore this design space using a DNA-encoded recipe consisting of multiple biomolecular reactions that dictate the time-dependent binding strength and specificity of each type of subunit in the sample independently, which makes it possible to program an assembly pathway that leads to a kinetically trapped final state. With this kinetic control, we show that the same set of building blocks can form clusters with different final structures. These structures, with tunable core-shell compositions, have feature sizes much larger than the building block size and are governed by the DNA-encoded assembly kinetics. Contrasting global kinetic control strategies such as thermal annealing, tuning the timing of individual biomolecular reactions offers the opportunity to regulate how the activity of each separate co-assembling component of a large set varies over time, opening up the potential for morphogenesis-like assembly processes involving engineered species.
Soft Condensed Matter (cond-mat.soft)
9 pages, 5 figures
Trace Element Behavior during Shock Transformation of Zircon to Reidite
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
A. A. Shiryaev, A. N. Zhukov, V. V. Yakushev, A. A. Averin, V. O. Yapaskurt, A. Yu. Borisova, A. Yu. Bychkov, O. G. Safonov, I. V. Lomonosov
Large single crystals of natural zircon were shock-loaded at 13.6 and 51.3 GPa in planar geometry. No structural changes were observed after loading at 13.6 GPa. Loading to 51.3 GPa resulted in zircon transformation to a denser scheelite-structured phase, reidite. The investigation of reidite samples by X-ray diffraction, Raman, photo- and cathodoluminescence spectroscopies revealed segregation of some trace cations (such as REE) on planar defects during the transformation. The segregation has occurred in a laboratory experiment without long-term annealing after the shock loading. A possible mechanism of the segregation of trivalent trace cations assumes local violation of charge balance during the zircon-reidite reconstructive transformation, which is accompanied by changes in the topology of polyhedra and second coordination spheres (Si-Zr). This results in expulsion of a fraction of the trace elements into energetically expensive interstitial positions with high diffusivity even at relatively low temperatures.
Materials Science (cond-mat.mtrl-sci)
Petrology, 33, 2025, 489
Accelerating Crystal Structure Prediction Using Data-Derived Potentials: High-Pressure Binary Hydrides
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
Lewis J. Conway, Chris J. Pickard
Crystal structures can be predicted from first-principles using ab initio random structure searching AIRSS and density functional theory (DFT). AIRSS provides a method to sample the potential energy landscape and DFT provides a robust and accurate description of that landscape. Classical interatomic potentials can describe energy landscapes at a significantly lower computational cost, typically at the expense of robustness and accuracy. Modern machine-learning interatomic potentials offer a compromise, with greater robustness and accuracy than classical potentials at a fraction of the computational cost of DFT. In this work, we use Ephemeral Data-Derived Potentials EDDPs to perform accelerated AIRSS calculations for the binary hydrides at 100 GPa. Since the training data is generated iteratively using AIRSS, the searches can be performed with no prior knowledge of hydrides. These potentials allow for more diverse searches, sampling a wider range of compositions, larger unit cells, and orders-of-magnitude more structures. In addition to recovering many of the known structures, the searches reveal structures such as the hydrogen-rich phases of H$ _{22}$ (BrH), H$ _{23}$ Pb, and H$ _{32}$ Mg, supermolecular phases of H$ _{25}$ Cs and H$ _{26}$ Rn, and many substoichiometric variants of known hydrides. Our results indicate that using the current generation of pretrained universal MLIPs to search for novel high-pressure hydrides is less effective due to model instabilities or markedly slower inference speeds and highlight the necessity of generating new, targeted data to drive further discoveries.
Materials Science (cond-mat.mtrl-sci)
Revealing a hidden magnetic order in the triangular lattice antiferromagnet CuNdO$_2$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-30 20:00 EDT
Jonathan Gaudet, Dalmau Reig-i-Plessis, Bogeng Wen, Thomas J. Hicken, Jonas A. Krieger, Jan Peter Embs, Hubertus Luetkens, Adam A. Aczel, Stuart A. Calder, Matthew B. Stone, Hae-Young Kee, Alannah M. Hallas
We investigate the magnetic ground state of CuNdO$ _2$ , which is a delafossite with a triangular lattice of magnetic Nd$ ^{3+}$ ions that are well separated by non-magnetic Cu spacer layers. From inelastic neutron scattering measurements of the crystal electric field, we determine the strong Ising character of the pseudo-spin $ \frac{1}{2}$ Nd$ ^{3+}$ moments. Magnetic susceptibility and heat capacity measurements reveal the onset of long-range antiferromagnetic order at $ T_N=0.78$ K. While the magnetic transition is definitively observed with muon spin relaxation, accompanied by the formation of a weakly dispersing spin wave excitation, no dipole-ordered moment is detected with neutron diffraction. We show that the apparent absence of a dipolar ordered moment is a consequence of the dominant Ising character of the Nd$ ^{3+}$ moments, which experience extreme frustration on the triangular lattice. Consequently, the frustration in CuNdO$ _2$ is relieved through in-plane ordering of the substantially smaller perpendicular component of the Nd$ ^{3+}$ moments into a 120\textdegree\ structure, with a nearly vanishing ordered moment.
Strongly Correlated Electrons (cond-mat.str-el)
Phase transitions and polarization switching in quasi-one-dimensional organic ferroelectrics of phenyltetrazole family
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
Pseudospin models are proposed for description of the phase transitions, dielectric characteristics, and polarization switching in two crystals of the phenyltetrazole family. One of them, APHTZ, is a canted ferroelectric, whereas the other, MPHTZ is a simple antiferroelectric. In APHTZ the electric field, applied perpendicularly to the axis of spontaneous polarization, flips the polarization in one of the two sublattices, effectively rotating the non-zero net polarization by 90$ ^\circ$ and switching the system between two different ferroelectric configurations. The temperature-electric field phase diagrams are constructed. The diagram topology appears to be typical for the Ising-like antiferroelectric systems.
Materials Science (cond-mat.mtrl-sci)
11 pages, 11 figures
DFT prediction of new o-MAX phases: Mo2A2AlC3 (A = Zr, Nb, Ta) for next-generation thermal barrier coatings
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
M. I. A. Tanim, C. Talukder, S. S. Saif, Labib H. K. Adnan, N. Jahan, M. M. Hossain, M. M. Uddin, M. A. Ali
The incorporation of o-MAX phases, characterized by out-of-plane atomic arrangements, provides valuable extensions to the MAX phase family, driven by their superior thermomechanical properties, which are suitable for high-temperature applications. In this research, three novel o-MAX phases, Mo2A2AlC3 (A = Zr, Nb, Ta), have been newly explored, and their structural geometry, electronic properties, mechanical behavior, thermodynamic characters, and optical response have been comprehensively investigated employing density functional theory (DFT) for the first time.
Materials Science (cond-mat.mtrl-sci)
50 pages
Fabrication of oxide/FeSe multilayer films using the PLD technique
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-30 20:00 EDT
Tomoki Kobayashi, Hiroki Nakagawa, Ryo Ogawa, Atsutaka Maeda
In this study, we demonstrate the successful fabrication of TiO2/FeSe/STO and TiO2/FeSe/LaAlO3 heterostructures using PLD. When the growth rates were sufficiently low, anatase TiO2, which has been reported to induce superconductivity in FeSe, could be grown epitaxially on FeSe. For TiO2/FeSe/STO, the FeSe/TiO2 interface was relatively clean, as confirmed by the observation of Laue fringes in FeSe(001) reflection. Although a thinner FeSe layer is expected to enhance Tc, our results instead suggest that deposition of TiO2 introduces additional disorder in FeSe. Most strikingly, superconductivity appeared when TiO2 was deposited on FeSe/LaAlO3, clearly demonstrating that the interaction between the top oxide layer and underlying FeSe can induce superconductivity. This work demonstrates the feasibility of fabricating FeSe/oxide superlattices by PLD, establishing a novel platform for the exploration of interfacial superconductivity in iron-based superconductors.
Superconductivity (cond-mat.supr-con)
14 pages, 3 figures
Chiral Analogues of Knit Stitches Designed Using Chiral Topology
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-30 20:00 EDT
Shunsuke Takano, Yusuke Kochi, Ken’ichi Yoshida, Elisabetta A. Matsumoto, Yuka Kotorii, Toru Asahi, Katsuya Inoue
Fabrics are flexible thin structures made of entangled yarn or fibers, yet the topological bases of their mechanics remain poorly understood. For weft knitted fabrics, we describe how the entanglement of adjacent stitches contributes to the flexibility of the fabric. Interpreting heterogeneous stitch pairs as domain boundaries reveals that the step between pairs of neighboring stitches is responsible for direction-specific flexibility. In typical knitted fabrics, anisotropic flexibility can be attributed to latticed domain boundaries. The intersections between domain boundaries result in point defects that induce frustration that resembles the impossible Penrose stairs. We identify these by a chiral characteristic, defined summing the ascending or descending steps in a cycle surrounding the defect. Remarkably, seed fabric, a knit with high flexibility in both course and wale directions, is characterized as a racemic crystal of these chiral point defects.
Soft Condensed Matter (cond-mat.soft), Mathematical Physics (math-ph)
Tunable quantum metric and band topology in bilayer Dirac model
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-30 20:00 EDT
Xun-Jiang Luo, Xing-Lei Ma, K. T. Law
Quantum metric, a fundamental component of quantum geometry, has attracted broad interest in recent years due to its critical role in various quantum phenomena. Meanwhile, band topology, which serves as an important framework in condensed matter physics, has led to the discovery of various topological phases. In this work, we introduce a bilayer Dirac model that allows precise tuning of both properties. Our approach combines two Dirac Hamiltonians with distinct energy scales; one producing relatively dispersive bands and the other yielding relatively flat bands. The dispersive and flat bands are weakly coupled via hybridization $ \lambda$ . By inducing a band inversion in the layer subspace, we achieve flexible tuning of band topology across all Altland-Zirnbauer symmetry classes and quantum metric scaling as $ g \propto 1/\lambda^2$ near band inversion point. Using the bilayer Su-Schrieffer-Heeger model, we investigate the localization properties of gapless boundary states, which are affected by quantum metric. Our work lays a foundation for exploring the interplay between band topology and quantum metric.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
8 pages, 5 figures
Tetratomic states of microwave dressed and associated ultracold 23Na40K molecules
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-09-30 20:00 EDT
Zhengyu Gu, Xuansheng Zhou, Wei Chen, Wei Han, Fulin Deng, Tao Shi, Pengjun Wang, Jing Zhang
Ultracold diatomic molecules have achieved significant breakthroughs in recent years, enabling the exploration of quantum chemistry, precision measurements, and strongly correlated many-body physics. Extending ultracold molecular complexity to polyatomic molecules, such as triatomic and tetratomic molecules, has attracted considerable interest. However, the realization of ultracold polyatomic molecules remains technically challenging due to their complex energy-level structures. While only a few experiments have successfully demonstrated the formation of polyatomic molecules by magnetoassociation or electroassociation, here we present the first step toward producing tetratomic molecules through the development of a microwave association technique combined with microwave dressing. When the two lowest rotational states of the molecules are dressed by a microwave field, weakly bound tetramer states emerge in the entrance channel with free dark excited states $ \ket{0}$ and a dressed state $ \ket{+}$ . The spectroscopy of these weakly bound tetramers is probed by another microwave field that drives transitions from the populated dressed states $ \ket{+}$ . By precisely discriminating the complex hyperfine structure of the dark excited level $ \ket{0}$ from the dressed-state spectroscopy, the binding energy of the tetratomic molecules is measured and characterized. Our work contributes to the understanding of complex few-body physics within a system of microwave-dressed molecules and may open an avenue toward the creation and control of ultracold polyatomic molecules.
Quantum Gases (cond-mat.quant-gas)
11 pages, 8 figures
Twist-Free Enhancement of Strength and Modulus in Electrospun Yarns via Liquid-Assisted Capillary Densification
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-30 20:00 EDT
Saujatya Mandal, Sonu Dhiman, Debashish Das
Electrospun yarns often fall short of the strength and stiffness of their constituent nanofibers because of loose packing and inter-fiber slip. We report a simple, twist-free route to close this gap by liquid-assisted rolling: yarns are briefly wetted (water or ethanol) and subjected to gentle rolling action (mechanical strokes perpendicular and parallel to the yarn axis), then dried under controlled conditions so that meniscus forces compact the assembly into tightly bound bundles. The treatment yields large gains in tensile strength and modulus, and as yarn diameter decreases the properties of liquid-treated yarns approach single-fiber limits, indicating more efficient load transfer. Dry-rolling controls produce negligible changes compared to as-spun yarns, confirming that capillarity-driven consolidation, rather than mechanical pressing, dominates the improvement. Water consistently outperforms ethanol, reflecting its larger elastocapillary driving term gamma\ast(1 + cos theta) on PAN and thus stronger capillary compaction; a short post-treatment anneal near Tg further increases stiffness with a corresponding reduction in ductility. To rationalize these trends, we quantify microstructure via SEM-derived alignment and packing density and show that these complementary descriptors jointly explain variability in mechanical response. A compact constitutive framework, grounded in distributed fiber recruitment and adhesion/frictional contact, captures the observed strengthening-ductility trade-off across processing routes. The results establish capillarity-driven consolidation as a scalable pathway to engineer processing-structure-property relationships in hierarchical polymer fiber assemblies and provide practical guidance for upgrading electrospun yarns, alone or as precursors to twisted and composite architectures.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
Submitted to Polymer (Elsevier) on 19 Sep 2025
Novel Market Temperature Definition Through Fluctuation Theorem: A Statistical Physics Framework for Financial Crisis Prediction
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-30 20:00 EDT
Masoome Ramezani, Fereydoun Rahnama Roodposhti, Ghanbar Abbaspour Esfeden, Mehdi Ramezani
This paper introduces a novel approach to financial crisis prediction by establishing a thermodynamic-like framework derived from the fluctuation theorem of statistical physics. We define market temperature through the probability ratio of positive to negative returns and demonstrate its effectiveness in identifying market states and predicting potential crises. Our empirical analysis spans nine major global indices from 2005 to 2025, revealing statistically significant differences in temperature dynamics between crisis and non-crisis periods. Most notably, we discover a counterintuitive relationship between market temperature stability and crisis occurrence: crises tend to emerge more frequently during periods of apparent temperature stability rather than instability. This finding suggests that unusually stable periods in market temperature might signal the accumulation of systemic risks, similar to the calm before a storm in physical systems.
Statistical Mechanics (cond-mat.stat-mech)
18 pages, 10 figures
Field-free superconducting diode effect of NbSe2 induced by strain
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
Jiajun Li, Minhao Zou, Fengyi Guo, Dai Zheng, Yiying Zhang, Yu Du, Fuwei Zhou, Heng Zhang, Wuyi Qi, Tianqi Wang, YeFan Yu, Rui Wang, Fucong Fei, Hao Geng, Fengqi Song
Superconducting diodes, similar to semiconductor diodes, possess unidirectional superconducting properties and are the fundamental units for constructing superconducting quantum computing, thus attracting widespread attention. At present, most of superconducting diodes require an external magnetic field or proximity effect to break time reversal symmetry (TRS). The cases of intrinsic superconducting diode effect (SDE) under zero magnetic field are relatively scarce, and there are still some puzzles especially regarding the reasons for the TRS breaking. Here, we not only report field free SDE in NbSe2 induced by strain, but also large values of the difference of Ic+ and |Ic-| ({\Delta}Ic) of 286 {\mu}A and the superconducting diode efficiency ({\eta}) of 6.76 % are achieved. Interestingly, {\Delta}Ic varies with the magnetic field and exhibits two distinct evolutionary behaviors with B-odd or B-even symmetry in various devices. We attribute this to the selective activation of two independent, spatially-orthogonal mechanisms: a stress-induced real-space polarity and a field-induced reciprocal-space asymmetric energy bands. In general, we propose an extremely effectively method to produce field free SDE, even when the material itself does not possess field free SDE, and provide new perspectives to understand the SDE which build new avenues for superconducting quantum devices.
Materials Science (cond-mat.mtrl-sci)
15 pages, 4 figures
Power-Law Spectra and Asymptotic $ω/T$ Scaling in the Orbital-Selective Mott Phase of a Three-Orbital Hubbard Model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-30 20:00 EDT
Quantum materials whose properties lie beyond the celebrated Landau Fermi-liquid paradigm have been observed for decades across diverse material platforms. Finding microscopic lattice models for metallic states that exhibit such peculiar behavior remains a major theoretical challenge, as these features often originate from strong quantum fluctuations in strongly interacting electron systems. Here we investigate a three-orbital Hubbard model at a high-symmetry point that hosts a transition from a metallic to an orbital-selective Mott (OSM) phase. Employing single-site dynamical mean-field theory combined with full-density-matrix numerical renormalization group, we chart the $ T-U$ phase diagram and obtain high-resolution real-frequency dynamics. In the OSM regime we find asymptotically scale-invariant (power-law) single-particle spectra and asymptotic $ \omega/T$ scaling in both charge and spin channels, spanning several decades in frequency and temperature.
Strongly Correlated Electrons (cond-mat.str-el)
Domain Boundaries in a Metallic Distortive Polar Metal
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
Adrian Savovici, Barak Ratzker, Xuyang Zhou, Stefan Zaefferer, Martina Ruffino, Iliya Radulov, Patricia Jovičević-Klug, Shyam Katnagallu, Amir Hamzehei, Philipp Watermeyer, Alexandra Vogel, Jörg Neugebauer, Christoph Freysoldt, Dierk Raabe
Polar metals are an underexplored material class combining two properties that are typically incompatible, namely a polar crystal structure and reasonable electrical conductivity. While intriguing given that metals favor centrosymmetry, these materials also exhibit potential functional properties relevant to memory, optoelectronic, catalytic, and other applications. The distortive polar metal (DPM) subclass forms through a centrosymmetry-lifting phase transformation into a polar crystal structure. In the process, domains with uniform geometric polar directions form, oftentimes separated by domain boundaries with polarity discontinuities arranged in “charged” head-to-head (H-H) or tail-to-tail (T-T) morphologies. To date, only metallic oxide DPM microstructures have been studied. Here we reveal in the intermetallic DPM Mn5Al8 different chemical reactivity and surface interactions at domain boundaries depending on their H-H or T-T character. Variable surface electron-transfer reactivity suggests localized changes in electronic work functions due to an increase (H-H) or depletion (T-T) in the electronic density of states. This behavior is unintuitive in a metal where electrostatic de-polarizing fields should not account for fluctuations in carrier densities. These findings suggest that metallic DPMs may offer functionalizable domain boundary behavior and deserve increased attention. Metallic DPMs allow highly tunable chemistries that can undergo various thermomechanical processing and transformation protocols. Ultimately, this study marks a milestone in metal physics and uncovers novel intermetallic properties, propelling the discovery and design of advanced electronic materials and devices.
Materials Science (cond-mat.mtrl-sci)
Gap Inhomogeneity in Cuprates: a view from Two-Dimensional Josephson Echo Spectroscopy
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-30 20:00 EDT
Alex Gómez Salvador, Ivan Morera, Marios H. Michael, Pavel E. Dolgirev, Danica Pavicevic, Albert Liu, Andrea Cavalleri, Eugene Demler
Novel theoretical developments have allowed to connect microscopic disorder in bosonic collective excitations to the signatures in two-dimensional terahertz spectroscopy (Gómez Salvador et al. 2025). Here, we employ this framework to analyze the recently measured Josepshon echoes in optimally doped La$ _{2-x}$ Sr$ _x$ CuO$ _4$ (Liu et al. 2024). We consider the spatial gap inhomogeneities -observed in scanning tunneling microscopy- as input for the disorder in the superfluid density, and compute the resulting echo peaks. The excellent agreement supports the interpretation that the gap inhomogeneity arises solely from pairing gap fluctuations, with no evidence for non-superconducting competing local orders. Finally, we study the microscopic origin of the inelastic processes, contributing to the damping of the Josephson plasmon at low temperatures, and conclude that it can be attributed to nodal quasiparticles.
Superconductivity (cond-mat.supr-con)
5+2 pages, 3+1 figures
Twinning Relationships in Coexisting Cubic and Tetragonal Phases of Ferroelectrics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
S. Gorfman, I. Biran, N. Zhang, Z.-G. Ye
Many ferroelectric materials undergo thermally driven transitions between cubic and tetragonal phases. Despite being well-known for decades, such transitions still pose unresolved questions, particularly about the role of domains in shaping the transition pathway. It is understood that tetragonal domain assemblages are crucial for mismatch-free coexistence of both tetragonal and cubic phases, as described by the Weschler-Lieberman-Read (WLR) crystallographic theory. However, direct experimental characterization of domain patterns during the phase transition remains challenging. Here, we enhance the single-crystal X-ray diffraction to investigate domain microstructures during cubic-tetragonal phase transition, leveraging the bulk-penetrating and non-destructive character of this method. We extend the WLR model by the analytical expressions for the orientation relationships between the real and reciprocal bases of the cubic phase and tetragonal domains. We systematically catalogue the Bragg peak separations for 24 possible coexistence variants and validate these predictions using 3D reciprocal space maps from a piezo-/ferroelectric PMN-35PT crystal at phase coexistence temperatures. Our results provide a framework for interpreting domain configurations during the phase transition and offer insights applicable to other systems involving orientation relationships in coexisting phases.
Materials Science (cond-mat.mtrl-sci)
31 pages, 9 figures, 2 Appendices
Superconductivity Proximate to Non-Abelian Fractional Spin Hall Insulator in Twisted Bilayer MoTe$_2$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-30 20:00 EDT
Cheong-Eung Ahn, Gyeoul Lee, Donghae Seo, Youngwook Kim, Gil Young Cho
Twisted bilayer MoTe$ _2$ near two-degree twists has emerged as a platform for exotic correlated topological phases, including ferromagnetism and a non-Abelian fractional spin Hall insulator. Here we reveal the unexpected emergence of an intervalley superconducting phase that intervenes between these two states in the half-filled second moiré bands. Using a continuum model and exact diagonalization, we identify superconductivity through multiple signatures: negative binding energy, a dominant pair-density eigenvalue, finite superfluid stiffness, and pairing symmetry consistent with a time-reversal-symmetric nodal extended $ s$ -wave state. Remarkably, our numerical calculation suggests a continuous transition between superconductivity and the non-Abelian fractional spin Hall insulator, in which topology and symmetry evolve simultaneously, supported by an effective field-theory description. Our results establish higher moiré bands as fertile ground for intertwined superconductivity and topological order, and point to experimentally accessible routes for realizing superconductivity in twisted bilayer MoTe$ _2$ .
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Superconductivity (cond-mat.supr-con)
6 pages, 3 figures
Universality classes of Anderson localization transitions in disordered three-dimensional non-Hermitian systems with exceptional points
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-09-30 20:00 EDT
We conduct a numerical study of wave localization in disordered three-dimensional non-Hermitian systems featuring exceptional points. The energy spectrum of a disordered non-Hermitian Hamiltonian, exhibiting both parity-time and parity-particle-hole symmetries, forms a cross in the complex energy plane, with an exceptional point fixed at the origin. Near the exceptional point, the system experiences a disorder-driven quantum phase transition from extended to localized states, characterized as an Anderson localization transition in non-Hermitian systems. Notably, we identify a universal critical exponent that remains independent of the distribution of random variables. The model also supports Anderson localization transitions away from the exceptional points, albeit with different critical exponents. Furthermore, we investigate wave localization in a non-Hermitian system lacking parity-time symmetry, revealing distinct universality classes. By comparing the obtained critical exponents with those reported in the literature, we conclude that the presence of exceptional points introduces new universality classes that extend beyond the established 38-fold symmetry classification for non-Hermitian systems.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
9 pages, 4 figures
Tensor Network Markov Chain Monte Carlo: Efficient Sampling of Three-Dimensional Spin Glasses and Beyond
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-30 20:00 EDT
Tao Chen, Jing Liu, Youjin Deng, Pan Zhang
Sampling the three-dimensional (3D) spin glass – i.e., generating equilibrium configurations of a 3D lattice with quenched random couplings – is widely regarded as one of the central and long-standing open problems in statistical physics. The rugged energy landscape, pronounced critical slowing down, and intrinsic ergodicity breaking render standard Monte Carlo methods severely inefficient, particularly for large systems at low temperatures. In this work, we introduce the Tensor Network Markov Chain Monte Carlo (TNMCMC) approach to address the issue. It generates large-scale collective updates in MCMC using tensor networks on the 2D slices of the 3D lattice, greatly improving the autocorrelation time and offering orders-of-magnitude speed-ups over conventional MCMC in generating unbiased samples of the Boltzmann distribution. We conduct numerical experiments on 3D spin glasses up to system size $ 64\times 64\times 64$ using a single CPU, and show that TNMCMC dramatically suppresses critical slowing down in large disordered systems, which usually require a supercomputer to perform MCMC simulations. Furthermore, we apply our approach to the 3-state Potts model up to system size $ 64\times 64\times 64$ using a single CPU, and show that the TNMCMC approach efficiently traverses the exponential barriers of the strong first-order transition, whereas conventional MCMC fails. Our results reveal that TNMCMC opens a promising path toward tackling long-standing, formidable three-dimensional problems in statistical physics.
Statistical Mechanics (cond-mat.stat-mech), Disordered Systems and Neural Networks (cond-mat.dis-nn), Computational Physics (physics.comp-ph)
Challenges and opportunities in orbitronics
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-30 20:00 EDT
Shunsuke Fukami, Kyung-Jin Lee, Mathias Kläui
The spin of the electron has been a key enabler to realize spintronics devices that harness the spin degree of freedom beyond conventional charge-based electronics. In addition to spin, electrons have another degree of freedom associated with the angular momentum: orbital angular momentum. While spintronics has evolved fast and spintronics concepts are now used in magnetic sensors and nonvolatile memories, exploiting orbital angular momentum has just started to be studied. Phenomena mediated by orbital angular momentum have led to a new branch of spintronics called orbitronics. This Perspective discusses how orbitronics can constitute the next step in the evolution of spintronics by reviewing the current understandings and experimental results of orbital effects and summarizing the open questions. Prospects and challenges for devices in particular in non-volatile memory are discussed as an applications perspective.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Strain-induced Dynamic Spin-Phonon Coupling in Epitaxial RuO2 Films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
In Hyeok Choi, Seung Gyo Jeong2, Jae Hyuck Lee, San Kang, Sreejith Nair, Changyoung Kim, Dirk Wulferding, Bharat Jalan, Jong Seok Lee
Magnetic order parameters in altermagnets can couple to quantized lattice vibration via both piezomagnetic and magnetoelastic effects, leading to the renormalization of phonon dispersion. Here, we demonstrate photo-induced dynamic frequency modulation of THz phonons excited in anisotropically-strained epitaxial RuO2 thin films using ultrafast coherent phonon spectroscopy and time-resolved magneto-optic Kerr effect measurement. A coherent oscillation of a transverse acoustic phonon appears in the sub-THz range with increasing film thickness above 4 nm due to local dislocation arising from the anisotropic strain relaxation, which hosts large non-zero shear strain. Interestingly, this phonon mode exhibits a time-varying mode hardening below ~ 500 K. Furthermore, an optical phonon oscillation emerges in magnetization dynamics of the photo-induced non-equilibrium state, and it becomes significantly softened near the critical temperature, while there is no observable magneto-optic signal in fully-strain-relaxed films. Such notable dynamic frequency modulations in acoustic and optical phonons offer an opportunity to manipulate phonons in the THz range through the spin-phonon coupling controlled by epitaxial design, which can inspire the new class of altermagnetic applications in the ultrafast quantum opto-spintronics.
Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
Stationary densities and delocalized domain walls in asymmetric exclusion processes competing for finite pools of resources
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-30 20:00 EDT
Sourav Pal, Parna Roy, Abhik Basu
We explore the stationary densities and domain walls in the steady states of a pair of asymmetric exclusion processes (TASEPs) antiparallelly coupled to two particle reservoirs without any spatial extent by using the model in Haldar et al, Phys. Rev. E {\bf 111}, 014154 (2025). We show that the model admits {\em delocalized} domain walls which exist for some choices of the model parameters that define the effective entry and exit rates into the TASEP lanes. Surprisingly, in the parameter space spanned by these model parameters, the delocalized domain walls covers an {\em extended} region. The corresponding phase diagrams in the plane of the control parameters have different topology from those for an open TASEP or other models with multiple TASEPs connected to two reservoirs.
Statistical Mechanics (cond-mat.stat-mech)
Preliminary version
One-dimensional lattice random walks in a Gaussian random potential
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-30 20:00 EDT
Silvio Kalaj, Enzo Marinari, Gleb Oshanin, Luca Peliti
We study random walks evolving in continuous time on a one-dimensional lattice where each site $ x$ hosts a quenched random potential $ U_x$ . The potentials on different sites are independent, identically distributed Gaussian random variables. We analyze three distinct models that specify how the transition rates depend on $ U_x$ : the random-force-like model, random walks with randomized stepping times, and the Gaussian trap model. Our analysis focuses on five key disorder-dependent quantities defined for a finite chain with $ N$ sites: the probability current, its reciprocal (the resistance), the splitting probability, the mean first-passage time $ T_N$ , and the diffusion coefficient $ D_N$ in a periodic chain. By determining the moments of these random variables, we demonstrate that the probability current, resistance, and splitting probability are not self-averaging, which leads to pronounced differences between their average and typical behaviors. In contrast, $ T_N$ and $ D_N$ become self-averaging when $ N \to \infty$ , though they exhibit strong sample-to-sample fluctuations for finite $ N$ .
Statistical Mechanics (cond-mat.stat-mech)
C-BerryTrans: A C++ code for first-principles calculation of Berry-curvature-driven anomalous Hall and Nernst conductivities
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
Vivek Pandey, Sudhir K. Pandey
We present C-BerryTrans, a C++ code designed for first-principles calculations of Berry-curvature-driven transverse transport properties, namely the anomalous Hall conductivity (AHC) i.e., $ \sigma_{\mu \nu}^{AHC}$ and anomalous Nernst conductivity (ANC) i.e., $ \alpha_{\mu \nu}^{ANC}$ . The code directly extracts eigenvalues and momentum-matrix elements from WIEN2k calculations and evaluates the Berry curvature ($ \boldsymbol\Omega$ ) using a Kubo-like formalism. For computational efficiency, C-BerryTrans parallelizes $ \boldsymbol\Omega$ evaluation over k-points using OpenMP and stores band-resolved curvature in binary format. This design enables rapid post-processing of AHC and ANC over a wide range of temperatures and chemical potentials ($ \mu$ ) in a single run. The code has been benchmarked on well-studied ferromagnetic materials (Fe, Fe$ _3$ Ge, Pd, Fe$ 3$ Al, and Co$ 2$ FeAl). For Fe, the $ \sigma{xy}^{AHC}$ is obtained to be $ \sim$ 775 ($ \sim$ 744) $ S/cm$ at 0 (300) K. In case of Fe$ 3$ Ge, the calculated value of $ \sigma{xy}^{AHC}$ is found to be 311 $ S/cm$ at the room temperature. Nextly, for Co$ 2$ FeAl, the magnitude of computed value of $ \sigma{xy}^{AHC}$ at 2 K is found to be $ \sim$ 56 $ S/cm$ . Next, magnitude of $ \alpha{xy}^{ANC}$ for Pd is obtained to be $ \sim$ 0.97 $ AK^{-1}m^{-1}$ at 300 K. For Fe$ 3$ Al, the maximum magnitude of $ \alpha{xy}^{ANC}$ for $ T\leq$ 500 K is computed as $ \sim$ 2.83 $ AK^{-1}m^{-1}$ . Lastly, for Co$ 2$ FeAl, the value of $ \alpha{xy}^{ANC}$ is obtained to be $ \sim$ 0.10 $ AK^{-1}m^{-1}$ at 300 K. These results show good agreement with previously reported data. With its accuracy, scalability, and user-friendly workflow, C-BerryTrans provides a powerful tool for exploring $ \boldsymbol\Omega$ -driven transport phenomena and is well suited for high-throughput materials discovery.
Materials Science (cond-mat.mtrl-sci)
arXiv admin note: substantial text overlap with arXiv:2504.00123, arXiv:2505.19280
Field-theoretical form of the molecular dynamics method in condensed matter physics: relativistic quantum statistical thermodynamics
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-30 20:00 EDT
The principles of microscopic foundation of thermodynamics within the framework of relativistic quantum theory have been formulated
Statistical Mechanics (cond-mat.stat-mech)
16 pages, 2 figures
Quantum Saturation of Magnetoelectric Coupling in Fe$_3$O$_4$ Nanoparticles
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-30 20:00 EDT
Jian Huang, Fatemeh Aghabozorgi, Stephanie Brock
We report magnetoelectric coupling in nanoparticle assemblies that persists to temperatures over 300 times lower than in previous studies. The ME response saturates at low temperature, revealing a quantum plateau of the coupling. A field dependence analysis shows a crossover from quadratic to linear behavior, captured by a phenomenological expansion $ C(B,T) \simeq C_0(T) + a_1(T) B + a_2(T) B^2$ . The magnitude of the extracted quadratic coefficient, $ |a_2(T)|$ , follows a power law $ |a_2(T)| \sim T^{-\alpha}$ with $ \alpha \approx 1.15$ , indicating proximity to a quantum critical regime. The observed saturation reflects a new intrinsic energy scale, distinct from finite-size or extrinsic effects. These results establish nanoparticle assemblies as a new platform for studying quantum magnetoelectric phenomena.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
7 pages 4 figures
Design of model Boger fluids with systematically controlled viscoelastic properties
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-30 20:00 EDT
Jonghyun Hwang, Howard A. Stone
The subject of viscoelastic flow phenomena is crucial to many areas of engineering and the physical sciences. Although much of our understanding of viscoelastic flow features stem from carefully designed experiments, preparation of model viscoelastic fluids remains an outstanding challenge; for example, fabricating a series of fluids with varied fluid shear moduli $ G_0$ , but with an identical relaxation time $ \tau$ , is nontrivial. In this work, we harness the non-ideality of nearly constant-viscosity elastic fluids (commonly known as Boger fluids') made with polyisobutylene to develop an experimental methodology that produces a set of fluids with desired viscoelastic properties, specifically, $ G_0$ , $ \tau$ , and the first normal stress difference coefficient $ \psi_1$ . Through a simple linear algebraic manipulation between the rheological properties of interest ($ G_0$ , $ \tau$ , $ \psi_1$ ) and the fluid compositions in terms of polymer concentration $ c$ , molecular weight $ M_w$ , and solvent viscosity $ \eta_s$ , we developed a design equation’ that takes $ G_0$ , $ \tau$ , $ \psi_1$ as inputs and calculates values for $ c$ , $ M_w$ , $ \eta_s$ as outputs. Using this method, fabrication of sample viscoelastic fluids whose rheological properties are \textit{a priori} known can be achieved.
Soft Condensed Matter (cond-mat.soft), Fluid Dynamics (physics.flu-dyn)
11 pages, 7 figures, submitted to Journal of Rheology
Effect of Tube Radius on the Adsorption of Chlorothalonil on Single-Walled Carbon and Boron Nitride Nanotube Surfaces: A Theoretical Study for Environmental Remediation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
Francisco Gleidson de S. Ferreira, Caio V. C. Ribeiro da Silva, Silvete Guerini, Kleuton A. L. Lima, Douglas Soares Galvão, José Milton Elias de Matos, Alexandre Araujo de Souza
We investigated the interaction of the pesticide chlorothalonil (CLT) with single-walled carbon nanotubes (CNTs) and boron nitride nanotubes (BNNTs) using density functional theory (DFT) with the SIESTA code. Structural, energetic, and electronic analyses were used to characterize adsorption on nanotube surfaces. The adsorption energy becomes more favorable as the tube radius increases, consistent with enhanced pi-pi stacking on less curved surfaces. Both CNTs and BNNTs physisorb CLT; however, BNNTs appear more promising for CLT detection and removal in contaminated environments. The tube radius strongly affects the computed electronic and energetic descriptors. Complementary molecular dynamics simulations in GROMACS confirm the stability of CLT adsorbed on CNT and BNNT surfaces in aqueous solution.
Materials Science (cond-mat.mtrl-sci)
18 pages,7 figures
Structural, optical, and electrical properties of Cu-doped NiO films synthesized by spray pyrolysis for potential gas sensing applications
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
Eka Nurfani, Grace Grace, Mahardika Yoga Darmawan, Resti Marlina, Jumaeda Jatmika, Asnan Rinovian, Aditya Rianjanu
Cu-doped NiO thin films were deposited on ITO substrates via spray pyrolysis at 450 °C for 1.5 minutes. XRD confirmed a cubic NiO structure, with Cu incorporation reducing crystallite size, increasing interplanar spacing, and expanding the lattice parameter, indicating successful substitution of Cu ions. Optical analysis showed a slight bandgap reduction from 3.70 to 3.65 eV, while PL revealed lower emission intensity, suggesting enhanced defect states and suppressed carrier recombination. Raman spectroscopy exhibited redshifts in LO, 2TO, and 2LO modes and the disappearance of the TO mode, confirming lattice distortion from Cu doping. Gas sensing tests under ambient and LPG conditions demonstrated significantly improved sensitivity and voltage-dependent response for doped films. These results establish that Cu incorporation enhances charge transport and gas interaction mechanisms, making Cu-doped NiO films highly promising for efficient and reliable gas sensors.
Materials Science (cond-mat.mtrl-sci)
Demagnetization-Driven Nanoscale Chirality-Selective Thermal Switch
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
In Hyeok Choi, Daeheon Kim, Yeon Jong Jin, Seungmo Yang, Tae-Seong Ju, Changsoo Kim, Chanyong Hwang, Dongbin Shin, Jong Seok Lee
Chiral-lattice degrees of freedom can offer novel chirality-selective functionalities for thermotronic applications. Chiral phonons, carrying both heat and angular momentum, can emerge through a breaking of chiral degeneracy in the phonon bands, either via an intrinsic chiral crystal structure or by angular momentum transfer from photons or spins. This chiral controllability of the lattice dynamics enables a design of chiral thermo-devices by integrating ferromagnets with chiral materials. Here, we present a nanoscale chirality-selective thermal switch realized using a simple heterostructure composed of ferromagnetic [Co/Pt] multilayers and insulating chiral $ \alpha$ -SiO2, where an external magnetic field can control thermal transport properties. Our experimental results based on the magneto-optic thermometry reveal that the thermal conductivity of $ \alpha$ -SiO2 exhibits a clear dependence on both the magnetization direction of [Co/Pt] multilayers and the structural chirality of $ \alpha$ -SiO2, which is supported well by the first-principles-based molecular dynamic simulations. The magnetization-dependent thermal on/off ratio amounts to 1.07 at room temperature and increases to about 1.2 as temperature decreases to 50 K, due to a reduction of Umklapp phonon-phonon scattering rate in $ \alpha$ -SiO2. These findings provide the first experimental demonstration of the nanoscale chirality-selective thermal switch based on the ferromagnetic/chiral material heterostructure, highlighting its potential as a key technology for addressing heat dissipation challenges in nanoscale electronic devices.
Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
The role of the solid-melt interface in accelerating the self-catalyzed growth kinetics of III-V semiconductors
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
Zhucong Xi, Abby Liu, Xiaobo Chen, Meng Li, Dmitri N. Zakharov, Judith C. Yang, Rachel S. Goldman, Liang Qi
Solid-melt interfaces play a pivotal role in governing crystal growth and metal-mediated epitaxy of gallium nitride (GaN) and other semiconductor materials. Using atomistic simulations based on machine-learning interatomic potentials (MLIPs), we uncover that multiple layers of Ga atoms at the GaN-Ga melt interface form structurally ordered and electronically charged configurations that are critical for the growth kinetics of GaN. These ordered layers modulate the free energy landscape (FEL) for N adsorption and substantially reduce the migration barriers for N at the interface compared to a clean GaN surface. Leveraging these interfacial energetics, kinetic Monte Carlo (KMC) simulations reveal that GaN growth follows a diffusion-controlled, layer-by-layer mechanism, with the FEL for N adsorption emerging as the rate-limiting factor. By incorporating facet-specific FELs and the diffusivity/solubility of N in Ga melt, we develop a predictive, fitting-free transport model that estimates facet-dependent growth rates in the range of ~0.01 to 0.04 nm/s, in agreement with experimental growth rates observed in GaN nanoparticles synthesized by Ga-mediated molecular beam epitaxy (MBE). This multiscale framework offers a generalizable and quantitative approach to link atomic-scale ordering and interfacial energetics to macroscopic phenomena, providing actionable insights for the rational design of metal-mediated epitaxial processes.
Materials Science (cond-mat.mtrl-sci)
Bose glass in Ca$_2$RuO$_4$ nanofilms
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-30 20:00 EDT
Hiroyoshi Nobukane, Koki Hirose, Kakeru Isono, Mizuki Higashiizumi, Masahito Sakoda, Korekiyo Takahashi, Satoshi Tanda
Weak localization of bosons can give rise to an exotic quantum phase known as a Bose glass, characterized by the absence of global phase coherence yet finite conductivity. This phase is crucial in understanding the interplay between disorder, interactions, and superconductivity, especially in two-dimensional and strongly correlated systems. Here we report the presence of the Bose glass phase in the weak localization region of ruthenium oxide Ca$ _2$ RuO$ _4$ . The electrical resistance exhibits a characteristic logarithmic temperature dependence in this phase, $ \rho \sim \ln(1/T)$ . Through $ \beta$ -function scaling analysis, we observed “vertical flow” indicating unconventional scaling behavior associated with localized bosonic states. Our results suggest the existence of bosons-Cooper pairs-persisting up to high temperatures around 220 K and that these bosons undergo weak localization. In the Bose glass phase, vortices are found to have a dual relationship with the localized Cooper pairs, enabling their motion and resulting in finite resistance despite the presence of bosonic order. We identified two quantum critical points: one between the Bose glass and superconducting phases and another between the Bose glass and Mott insulating phases, allowing us to extract the corresponding quantum sheet resistances. We revealed that the ground state of the Ca$ _2$ RuO$ _4$ changes depending on the localization strength. Thinning the Ca$ _2$ RuO$ _4$ corresponds to controlling the electronic correlation by relieving the distortion in RuO$ _6$ octahedra. These findings offer significant insights into the interplay between electronic correlations and bosonic transport, with important implications for studying high-temperature superconductors based on perovskite structures.
Strongly Correlated Electrons (cond-mat.str-el)
High-Precision Temperature Estimation Based on Magnetic Nanoparticles Dominated by Brownian Relaxation under Combined AC and DC Magnetic Fields
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-30 20:00 EDT
Zhongzhou Du, Wenze Zhang, Yi Sun, Na Ye, Yong Gan, Pengchao Wang, Xinwei Zhang, Yuanhao Zhang, Shijie Han, Haochen Zhang, Haozhe Wang, Wenzhong Liu, Takashi Yoshida
Brownian relaxation is one of the primary mechanisms that allows magnetic nanoparticles (MNPs) to convert magnetic energy into thermal energy under an excitation magnetic field. Accurately characterizing the MNPs’ magnetization dynamics dominated by Brownian relaxation is crucial for achieving high-precision temperature estimation. However, the lack of a readily applicable analytical expression remains a major obstacle to the advancement of magnetic nanoparticle hyperthermia (MNPH). In this paper, the perturbation method was applied to derive analytical expressions from the Fokker-Planck equation, which characterized MNPs’ magnetization behaviors under the AC and DC magnetic fields. Numerical simulations were conducted to validate the accuracy of the analytical expressions and to explore the correlation between temperature and the magnetization response. Then, a temperature analysis model based on magnetization harmonics was constructed. The first and second harmonic ratios and first harmonic phase were used to calculate MNPs’ temperature, respectively. The experimental results demonstrate that within 310 K to 320 K, the estimation error of the temperature using the amplitude ratio of the first to second harmonics is below 0.0151 K, while the error using the first harmonic phase is below 0.0218 K. The derived analytical expressions are expected to enhance the accuracy of MNP-based temperature measurements and facilitate their broader applications in MNPH and MNP imaging.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Strong enhancement of d-wave superconductivity in an extended checkerboard Hubbard ladder
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-30 20:00 EDT
Xichen Huang, Saisai He, Jize Zhao, Zhong-Bing Huang
By employing the density-matrix renormalization group method, we study an extended checkerboard Hubbard model on the two-leg ladder, which includes an intraplaquette nearest-neighbour attraction V. The simulated results show that V plays a significant role in enhancing the d-wave superconductivity when the electron density is close to half-filling. In the homogeneous case t’=t (t and t’ are the intraplaquette and interplaquette hopping integrals), large critical |Vc| is required to induce the superconducting ground state. With decreasing t’, |Vc| is substantially diminished and the pair state has a nearly C4 symmetry. In the extremely inhomogeneous case t’<0.2t, the system transits to the d-wave superconducting phase at V\sim-0.3t and V\sim-0.4t for U=8t and U=12t, respectively, accompanying with a shift of spin and single-particle excitations from gapless to gapped type.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
Spin-stripes in the Hubbard model: a combined DMFT and Bethe-Salpeter analysis
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-30 20:00 EDT
Ruslan Mushkaev, Francesco Petocchi, Shintaro Hoshino, Philipp Werner
The Hubbard model is known to accommodate various electronic orders, including stripes, which are important for understanding the physics of cuprates. We study spin-stripe order in the square lattice Hubbard model as a function of doping and temperature, by solving the Bethe-Salpeter equa- tion with the local vertex from dynamical mean field theory (DMFT), both inside and outside the antiferromagnetic phase. We find broad regions of horizontal/vertical spin stripes at low tempera- tures for the model with and without next-nearest neighbor hopping. Their wavelength depends on hole doping in a nonlinear fashion, and is highly sensitive to the ratio of nearest and next-nearest neighbor hoppings.
Strongly Correlated Electrons (cond-mat.str-el)
High-energy electron-beam induced defect engineering of monolayer MoS2 for tunable optical properties
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-30 20:00 EDT
Anagha Gopinath, Faiha Mujeeb, Subhabrata Dhar, Jyoti Mohanty
Structural defects in 2D-transition metal dichalcogenides are critical in modulating their optical and electrical behavior. Nevertheless, precise defect control within the monolayer regime poses a significant challenge. Herein, a high-energy (1MeV) electron beam irradiation strategy is harnessed to induce defects in monolayer MoS2. Controlled variation of electron-beam irradiation time tunes the defect density, as reflected by the evolution of defect-mediated photoluminescence characteristics. The optically active defect emission appearing at approx. 200-300meV below the A exciton at 85K exhibits a systematic increase in intensity with prolonged exposure and saturates at higher laser excitation power. Circular polarization-resolved photoluminescence spectroscopy reveals strong suppression of valley polarization of the A exciton after irradiation. Complementary x-ray photoelectron spectroscopy identifies enhanced Mo-O bonding signatures in MoS2 following irradiation. Kelvin probe force microscopy indicates the transition to p-type doping behaviour. A detailed temperature and power-dependent photoluminescence measurements further elucidate the optical behaviour of these defect states. Density functional theory calculations using these configurations establish that the transition between the conduction band and acceptor states within the bandgap accounts for the defect emission. This work presents a tunable route for defect engineering in monolayer TMDs, enabling controlled tailoring of their structural and optical properties for optoelectronic, electronic and valleytronic applications.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Dipolar Interfacial Excitons in Lateral Semiconductor Heterostructures
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-30 20:00 EDT
Elie Vandoolaeghe, Francesco Fortuna, Suman Kumar Chakraborty, Biswajeet Nayak, Takashi Taniguchi, Kenji Watanabe, Prasana K. Sahoo, Thibault Chervy, Puneet A. Murthy
Interfaces between materials or phases – whether in condensed matter systems, biological membranes, or catalytic surfaces – are rich with phenomena that are fundamentally distinct from those present in the bulk. In some cases, interfaces host quasiparticles, such as surface plasmons or Majorana fermions, which can significantly influence the material properties. Here, we investigate a unique 1D interface formed between two monolayer 2D semiconductors, MoSe2, and WSe2, and unambiguously observe a new type of excitonic quasiparticle that resides exclusively at the boundary. Our optical measurements reveal several remarkable properties of this interfacial exciton. First, it possesses an in-plane dipole moment with exceptionally large dipole lengths of 2nm. The emission spectrum reveals narrow discrete states, indicating strong quantum confinement of the center-of-mass motion across the interface. Power-dependent measurements show a sublinear saturation behavior, reflecting interactions between dipolar excitons in this low-dimensional system. Moreover, the exciton displays striking sensitivity to charge carriers due to its dipolar character. Our results introduce a new platform for exploring interacting 1D dipolar bosonic systems with unique quantum properties and open pathways for novel optoelectronic devices, including applications in nonlinear quantum photonics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
11 pages, 4 figures
Charge-localization-driven metal-insulator phase transition in layered molecular conductors
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-30 20:00 EDT
Savita Priya, Maxim Wenzel, Olga Iakutkina, Marvin Schmidt, Christian Prange, Dieter Schweitzer, Yohei Saito, Reizo Kato, Koichi Hiraki, Martin Dressel
The organic conductor $ \alpha$ -(BEDT-TTF)$ _2$ I$ _3$ provides the prime example of a charge-order-driven metal-insulator transition. Restricted chemical substitution of S atoms by Se in the constituent molecules allows us to modify the electronic properties. This not only decreases the transition temperature but, in addition, alters the phase transition mechanism, resulting in the ground state deviating from the charge-ordered insulator state of the parent compound. Employing infrared optical spectroscopy, we investigate changes in the charge dynamics. Furthermore, we demonstrate the absence of charge ordering in the Se-substituted materials and suggest that the phase transition is instead driven by the localization of the itinerant charge carriers due to strong electron-phonon interactions.
Strongly Correlated Electrons (cond-mat.str-el)
Bromine-methanol etching of semiconductor crystals $Cd_{1-x}Zn_{x}Te_{1-y}Se_{y}$ with different selenium concentrations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
S.V. Naydenov, G.M. Babenko, O.K. Kapustnyk, I.M. Pritula
The effect of the selenium concentration in the composition of the $ Cd_{1-x}Zn_{x}Te_{1-y}Se_{y}$ semiconductor crystals on their etching with a bromine-methanol solution was studied. A thermodynamic model is proposed to describe the degree of etching of $ Cd_{1-x}Zn_{x}Te$ and $ Cd_{1-x}Zn_{x}Te_{1-y}Se_{y}$ crystals. A thermodynamic law is obtained for the first time to describe the change in the etching rate of $ Cd_{1-x}Zn_{x}Te_{1-y}Se_{y}$ crystals with different selenium concentrations. Experimental dependencies are constructed for etching trajectories and etching rates with 5% bromine-methanol solutions of $ Cd_{1-x}Zn_{x}Te_{1-y}Se_{y}$ crystal samples with nominal $ x\sim 0.1$ and selenium concentrations of $ y=0$ , $ y=0.02$ , $ y=0.06$ , and $ y=0.1$ . The average etching rates were 24$ {\mu }$ m/min, 18$ {\mu }$ m/min, 15$ {\mu }$ m/min, and 13$ {\mu }$ m/min. The threshold effect of a strong decrease in the etching rate upon transition from ternary $ Cd_{1-x}Zn_{x}Te$ to quaternary $ Cd_{1-x}Zn_{x}Te_{1-y}Se_{y}$ crystals, associated with hardening of the crystal structure, is identify and theoretically explained. The obtained experimental data are in good agreement with the theoretical estimates and will be useful for choosing the optimal regimes of crystal treatment.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph), Instrumentation and Detectors (physics.ins-det)
12 pages, 4 figures, 1 table
Nonequilibrium statistics of barrier crossings with competing pathways
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-30 20:00 EDT
Gulzar Ahmad, Sergey Saveliev, Steven P Fitzgerald, Marco G Mazza, Andrew J Archer
Many biological, chemical, and physical systems are underpinned by stochastic transitions between equilibrium states in a potential energy. Here, we consider such transitions in a minimal model with two possible competing pathways, both starting from a local potential energy minimum and eventually finding the global minimum. There is competition between the distance to travel in state space and the height of the potential energy barriers to be surmounted, for the transition to occur. One pathway has a higher energy barrier to go over, but requires traversing a shorter distance, whereas the other pathway has a lower potential barrier but it is substantially further away in configuration space. The most likely pathway taken depends on the available time for the transition process; when only a relatively short time is available, the most likely path is the one over the higher barrier. We find that upon varying temperature the overall most likely pathway can switch from one to the other. We calculate the statistics of where the barrier crossing occurs and the distribution of times taken to reach the potential minimum. Interestingly, while the configuration space statistics is complex, the time of arrival statistics is rather simple, having an exponential probability density over most of the time range. Taken together, our results show that empirically observed rates in nonequilibrium systems should not be used to infer barrier heights.
Statistical Mechanics (cond-mat.stat-mech), Statistics Theory (math.ST), Chemical Physics (physics.chem-ph)
17 pages, 11 figures
Synchronization transitions and spike dynamics in a higher-order Kuramoto model with Lévy noise
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-30 20:00 EDT
Dan Zhao, Jürgen Kurths, Norbert Marwan, Yong Xu
Synchronization in various complex networks is significantly influenced by higher-order interactions combined with non-Gaussian stochastic perturbations, yet their mechanisms remain mainly unclear. In this paper, we systematically investigate the synchronization and spike dynamics in a higher-order Kuramoto model subjected to non-Gaussian Lévy noise. Using the mean order parameter, mean first-passage time, and basin stability, we identify clear boundaries distingusihing synchronization and incoherent states under different stability indexes and scale parameters of Lévy noise. For fixed coupling parameters, synchronization weakens as the stability index decreases, and even completely disappears when the scale parameter exceeds a critical threshold. By varying coupling parameters, we find significant dynamical phenomena including bifurcations and hysteresis. Lévy noise smooths the synchronization transitions and requires stronger coupling compared to Gaussian white noise. Furthermore, we define spikes and systematically investigate their statistical and spectral characteristics. The maximum number of spikes is observed at small scale parameter. A generalized spectral analysis further reveals burst-like structure via an edit distance algorithm. Moreover, a power-law distribution is observed in the large inter-window intervals of spikes, showing great memory effects. These findings deepen the understanding of synchronization and extreme events in complex networks driven by non-Gaussian Lévy noise.
Statistical Mechanics (cond-mat.stat-mech), Adaptation and Self-Organizing Systems (nlin.AO)
Spontaneous $π$ flux trapping in granular rings of unconventional superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-30 20:00 EDT
We study Josephson couplings in unconventional superconductors from a symmetry-based perspective, extending the Sigrist-Rice formula to broader classes of pairing symmetries and in the presence of junction interface disorder effects. Applying this formalism to granular superconducting rings, we show that single-band chiral superconductors cannot spontaneously trap magnetic flux, which rules out chiral $ p$ -wave pairing as a candidate for $ \beta$ -Bi$ _2$ Pd superconductor, given the observation of half quantum flux in recent Little-Parks experiments. Taking into account the full crystalline symmetry and time-reversal symmetry of the superconducting state of $ \beta$ -Bi$ _2$ Pd, we propose that the effective pairing is a triplet helical equal-spin state, enforced by spin-orbit couplings arising from local inversion symmetry breaking. We further demonstrate that granular rings of such helical superconductors can support spontaneous flux trapping, even in the presence of strong junction interface orientation disorder. Our proposal reconciles apparent inconsistencies among different experimental observations and highlights the crucial role of local inversion symmetry breaking in understanding the pairing symmetry in $ \beta$ -Bi$ _2$ Pd.
Superconductivity (cond-mat.supr-con)
Cation accumulation drives the preferential partitioning of DNA in an aqueous two-phase system
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-30 20:00 EDT
Hiroki Sakuta, Yuki Akamine, Akari Kamo, Hao Gong, Norikazu Ichihashi, Arash Nikoubashman, Miho Yanagisawa
Mixtures of polyethylene glycol (PEG) and dextran (Dex) represent a widely used class of aqueous two-phase systems (ATPS), with applications ranging from the purification of various biomolecules such as nucleic acids to the synthesis of protocells. A key feature underlying these applications is the selective accumulation of biomolecules within Dex-rich droplets in an aqueous PEG phase, but the physical origin of this partitioning remains unclear. Depletion interactions were long assumed to be the primary driving force; however, our systematic experiments using DNA of different lengths indicate that depletion alone cannot fully explain the observed behavior. We identify an additional and previously underappreciated contribution from electrostatic interactions: Dex carries a slightly more negative charge than PEG, which drives preferential cation accumulation in the Dex-rich phase. These counterions facilitate the selective partitioning of DNA inside the Dex-rich droplets. This mechanism explains the dependency of DNA uptake in Dex-rich droplets on polymer length and salt concentration. Our findings establish Donnan-type ion partitioning as a central principle of nucleic acid localization in Dex-rich droplets, offering a unified explanation for this long-standing phenomenon. They lay the foundation for designing ATPS-based systems and help elucidate the physicochemical principles of biomolecular partition upon phase separation in cells.
Soft Condensed Matter (cond-mat.soft)
Main manuscript: 13 pages, 3 figures; SI: 12 pages, 6 figures
Detection of magnetic monopole in image potential states of topological insulators
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
Yang Zhan, Huaiyu Zhang, Yu Wang, Baojie Feng, Peng Cheng, Lan Chen
Magnetic monopoles, hypothetical particles behaving as isolated magnetic charges, have long been predicted by theories beyond the standard model but remain elusive in experimental detection. In this study, we demonstrate a novel method to induce and detect magnetic monopoles on the surface of three-dimensional (3D) topological insulators (TIs) using scanning tunneling microscopy (STM). By applying a radially distributed electric field via the STM tip to induce an image magnetic monopole using the topological magnetoelectric (TME) effect, we observe electric field-dependent intrinsic splitting peaks of image potential states (IPS) on the surface of a 3D high-order TI Bi(111). These IPS splitting phenomena originate from the Zeeman effect of the orbital magnetic moments interacting with the magnetic field generated by the magnetic monopoles. Our experimental results, supported by theoretical modeling, successfully demonstrate the detection of magnetic monopole. This work not only deepens our understanding of topological field theory and axion insulators but also opens new avenues for detecting and manipulating magnetic monopoles. The findings suggest that similar studies can be extended to other topological insulator systems, offering potential applications in quantum computing and novel electronic devices.
Materials Science (cond-mat.mtrl-sci)
The influence of solute induced memory on interface migration
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
Chad W. Sinclair, Jörg Rottler
Interface migration governs microstructural evolution during phase transformations and grain growth thereby dictating those material properties that depend on microstructure. Recent work continues to highlight the rich range of behaviors exhibited by migrating interfaces and the complex connection between these behaviors and the underlying atomistic processes that determine coarse-grained interfacial mobility. For interfaces moving at low homologous temperatures and small driving forces, we show that significant non-Markovian effects can arise that invalidate commonly used analysis methods. Specifically, we demonstrate that solute can act as a source of such non-Markovian motion. In turn, we introduce a time-local (TCL) propagator approach to account for memory-dominated short and intermediate time interface dynamics. This approach extrapolates to the long time diffusive limit, enabling robust mobility estimates from simulation windows far shorter than those required to observe linear scaling directly. Comparison with solute-free boundaries validates the method and quantifies solute drag in the Cahn-Hillert sense, providing a route to extract drag coefficients and effective mobilities across a range of solute concentrations. Our results demonstrate that analysis including memory is essential for connecting atomistic simulations to continuum models and offer a practical framework for studying interface kinetics in systems with slow internal processes.
Materials Science (cond-mat.mtrl-sci)
Strong Correlations and Superconductivity in the Supermoiré Lattice
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-30 20:00 EDT
Zekang Zhou, Cheng Shen, Kryštof Kolář, Kenji Watanabe, Takashi Taniguchi, Cyprian Lewandowski, Mitali Banerjee
The supermoiré lattice, arising from the interference of multiple moiré patterns, dramatically reshapes the electronic band structure by introducing new minibands and modifying band dispersion. Concurrently, strong electronic interactions within moiré flat bands lead to the emergence of various correlated states. However, the impact of the supermoiré lattice on the flat band systems with strong interactions remains largely unexplored. Here, we report the existence of the supermoiré lattice in the mirror-symmetry-broken twisted trilayer graphene, elucidating its role in generating mini-flat bands and mini-Dirac bands. Furthermore, we demonstrate interaction-induced symmetry-broken phases in the supermoiré mini-flat bands alongside the cascade of superconductor-insulator transitions enabled by the supermoiré lattice. Our work shows that robust superconductivity can exist in the mirror-symmetry-broken TTG and underscores the significance of the supermoiré lattice as an additional degree of freedom for tuning the electronic properties in twisted multilayer systems, sheds light on the correlated quantum phases such as superconductivity in the original moiré flat bands, and highlights the potential of using the supermoiré lattice to design and simulate novel quantum phases.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
Magnetoelectric Switching of Competing Magnetic Orders in Rhombohedral Graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-30 20:00 EDT
Kilian Krötzsch, Kenji Watanabe, Takashi Taniguchi, Arnaud Magrez, Mitali Banerjee
A finite Hall conductance under zero magnetic field implies time reversal symmetry (TRS) breaking due to magnetic ordering. In rhombohedral (RH) stacked graphene, the angular momentum breaking TRS can result from the orbital degree of freedom at the $ K$ and $ K’$ valleys. This leads to valley polarization and occupation-dependent anomalous Hall resistance (AHR) due to the chirality in Berry curvature between the valleys. We report magnetoelectric control of orbital magnetic order in crystalline rhombohedral hexalayer graphene (RHG), achieved without the introduction of a moiré superlattice. At moderate displacement fields and low carrier densities, we observe a non-volatile and hysteretic AHR that can be electrically toggled by sweeping either the carrier density or the displacement field. Upon the application of small perpendicular magnetic fields, the system reveals a characteristic double sign reversal of the AHR, indicating a competition between distinct magnetic ground states. This interplay between valley polarization, orbital magnetism, and electric and magnetic field tuning demonstrates the rich multiferroic behavior of RHG. Our findings present crystalline RHG as a minimal, tunable platform for studying symmetry-breaking phases and magnetic order in flat-band systems, offering insight into the coupling between electronic structure and magnetoelectric response.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Main text: 8 pages, 4 figures
Topological transitions controlled by the interaction range
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-30 20:00 EDT
Vlad Simonyan, Maxim A. Gorlach
We study a one-dimensional topological model featuring a Su-Schrieffer-Heeger type pattern of nearest-neighbor cou- plings in combination with the longer-range interactions exponentially decaying with the distance. We demonstrate that even relatively weak long-range couplings can trigger the topological transition if their range is large enough. This provides an additional facet in the control of topological phases.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics)
Robust Majorana Platform Driven by a Meissner-Induced Anisotropic Doppler Shift
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-30 20:00 EDT
Xiao-Hong Pan, Si-Qi Yu, Li Chen, Fu-Chun Zhang, Xin Liu
The realization of robust Majorana zero modes (MZMs), a cornerstone for fault-tolerant quantum computing, is hindered by the challenge of creating a platform that simultaneously offers a large topological gap, high tunability, and resilience to disorder. A system unifying these properties has remained elusive. Here, we propose and validate a novel platform that harnesses the Meissner effect in a topological insulator (TI) nanowire partially covered by a superconducting (SC) layer. Under an external magnetic field, Meissner screening currents in the SC induce a spatially varying Doppler shift on the TI surface. This effect generates a highly anisotropic effective g-factor, which selectively drives a topological phase transition localized on the nanowire’s bottom surface. This mechanism is crucial as it spatially separates the topological phase from the SC/TI interface, permitting strong proximity-induced superconductivity while preventing detrimental band renormalization at the interface from closing the topological gap. Furthermore, by confining the topological superconducting phase to the gate-tunable bottom surface, our platform fully leverages the intrinsic disorder resilience of the TI’s topologically protected surface states. Through a combination of supercurrent simulations, self-consistent Schrödinger-Poisson calculations, and large-scale tight-binding computations, we validate the platform’s robustness. Our work establishes a practical pathway toward Meissner-mediated topological superconductivity for realizing robust MZMs in SC/TI hybrid systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
9 pages, 5 figures
Griffiths phase emerging from strong mutualistic disorder in high-dimensional interacting systems
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-09-30 20:00 EDT
Tommaso Jack Leonardi, Amos Maritan, Sandro Azaele
The majority of analysis of interacting systems is done for weak and well-balanced interactions, when in fact topology and rare event factors often result in strong and sign-biased interactions when considering real systems. We analyse the impact of strong mutualistic interactions in a uniformly weighted Erdős-Rényi network under generalised Lotka-Volterra dynamics. In difference to the typical case we show the interaction topology and system dynamics combine to produce power law abundance distributions in a critical region of the phase diagram, identifiable as a Griffiths phase. We find asymptotic expressions for the fixed point solution in this region, and establish the boundary of this region as when topology alone determines the abundance distribution. We show that the Griffiths phase persists for strong mutualistic interactions more generally, and survives when combined with weak all-to-all competition.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech), Populations and Evolution (q-bio.PE)
20 pages, 5 figures
Intrinsic spin accumulation in magnetic spin Hall effect
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-30 20:00 EDT
The magnetic spin Hall effect is a time-reversal-odd phenomenon in which spin current is induced by the charge current. In the presence of a spin-orbit coupling and/or noncolinear magnetism, however, spin current is not uniquely defined. Instead, we study an intrinsic response of spin to an electric field gradient that describes the spin accumulation at the boundaries of magnetic systems. We derive a generic formula expressed by Bloch wave functions and apply it to a minimal model for representative altermagnets, RuO$ _{2}$ and MnF$ _{2}$ . Our results show that the intrinsic spin accumulation can be nonzero in magnetic insulators in sharp contrast to the magnetic spin Hall conductivity.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
14 pages, 8 figures
Fabrication of hydrogen-bonded metal inorganic-organic complex glasses by ligand-tuning approach
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
Tianzhao Xu, Zhencai Li, Jia-Xin Wu, Zihao Wang, Hanmeng Zhang, Huotian Zhang, Lars R. Jensen, Kenji Shinozaki, Feng Gao, Haomiao Zhu, Ivan Hung, Zhehong Gan, Jinjun Ren, Zheng Yin, Ming-Hua Zeng, Yuanzheng Yue
Metal inorganic-organic complex (MIOC) crystals are a new category of hybrid glass formers. However, the glass-forming compositions of MIOC crystals are limited due to lack of both a general design principle for such compositions and a deep understanding of the structure and formation mechanism for MIOC glasses. This work reports a general approach for synthesizing glass-forming MIOC crystals. In detail, the principle of this approach is based on the creation of hydrogen-bonded structural network by substituting acid anions for imidazole or benzimidazole ligands in the tetrahedral units of zeolitic imidazolate framework crystals. By tuning the metal centers, anions, and organic ligands of MIOCs, supramolecular unit structures can be designed to construct supramolecular networks and thereby enable property modulation. Furthermore, mixed-ligand synthesis yielded a mixed-crystal system in which the glass-transition temperature (Tg) can be linearly tuned from 282 K to 360 K through gradual substitution of benzimidazole for imidazole. Interestingly, upon vitrification, MIOCs were observed to undergo reorganization of hydrogen-bonded networks, with retention of tetrahedral units, short-range disorder, and the freezing of multiple conformations. This work offers a new strategy to systematically expand the glass-forming compositional range of MIOCs and to develop functional MIOC glasses.
Materials Science (cond-mat.mtrl-sci)
Quantum superconducting diode effect with perfect efficiency above liquid-nitrogen temperature
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-30 20:00 EDT
Heng Wang, Yuying Zhu, Zhonghua Bai, Zhaozheng Lyu, Jiangang Yang, Lin Zhao, X. J. Zhou, Genda Gu, Qi-Kun Xue, Ding Zhang
The superconducting diode is an emergent device that juggles between the Cooper-paired state and the resistive state with unpaired quasiparticles. Here, we report a quantum version of the superconducting diode, which operates solely between Cooper-paired states. This type of quantum superconducting diode takes advantage of quantized Shapiro steps for digitized outputs. The devices consist of twisted high-temperature cuprate superconductors, and exhibit the following distinguished characteristics: (1) a non-reciprocal diode behavior can be simply initiated by current training without applying an external magnetic field; (2) perfect diode efficiency is achieved under microwave irradiations at a record-high working temperature; (3) the quantized nature of the output offers high resilience against input noises. These features open up unprecedented opportunities toward developing practical dissipationless quantum circuits.
Superconductivity (cond-mat.supr-con)
Snakelike trajectories of electrons released from quantum dots driven by the spin Hall effect
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-30 20:00 EDT
Using time dependent simulations, we analyze the trajectories of electrons released from a quantum dot in a waveguide made of a spin-orbit-coupled material (InSb). An electron released from the quantum dot, when driven by an electric field follows a trajectory that is deflected by spin-orbit interaction and undergoes spin precession that results in a spin-dependent, snake-like trajectory. The trajectory strongly depends on the initial state of the electron, enabling detection of the electron quantum state in the dot when connected to the T-junction. Notably, we show that the snake-like trajectory persists even under a small external magnetic field with low, incomplete initial electron spin polarization. Our findings are supported by semiclassical calculations of the electron trajectory, which show good agreement with full quantum mechanical simulations
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Ligand co-deposition in focused electron beam induced nanoprinting: a predictive composition model
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-30 20:00 EDT
Jakub Jurczyk, Leo Brockhuis, Amalio Fernández-Pacheco, Ivo Utke
Recent advances in nanotechnology have created the need to manufacture three-dimensional nanostructures with controlled material composition. Focused Electron Beam Induced Deposition (FEBID) is a nanoprinting technique offering highest spatial resolution combined with the ability to directly 3D-print almost any shape. It relies on local electron-induced dissociation of metal-ligand organometallic molecules adsorbed onto a substrate. So far FEBID continuum modelling involved the surface kinetics of precursor molecules during electron irradiation and succeeded in the prediction of nanoprint shape and growth rate and forms nowadays the basis of software for 3D nano-printing of nanostructures. Here, we expand the model to the surface kinetics of detached ligands. Involving their dissociation and desorption behavior allows to predict trends in the metallic composition of the nanoprinted material and to define desirable nanoprint process windows as function of electron exposure time and flux. We present the theoretical foundations of the model, validate it experimentally for chromium and silver precursors, compare calculated values with literature data for various precursors, and discuss its potential to design new experiments. This contribution enhances our understanding of FEBID dynamics and provides a versatile framework for predictive FEBID material nano-printing.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
39 pages, 8 figures
Anisotropy by design in superconducting Nb thin films via ultrashort pulse laser irradiation
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-30 20:00 EDT
Javier Frechilla (1), Nicolas Lejeune (2), Elena Martínez (1), Emile Fourneau (2), Alejandro Frechilla (1), Sergio Martín (1), Leonardo R Cadorim (3,4), Luis A Angurel (1), Germán F de la Fuente (1), Alejandro V Silhanek (2), Milorad V Milosevic (4), Antonio Badía-Majós (1) ((1) Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, E-50018, Spain (2) Département de Physique, Q-MAT, CESAM, Université de Liège, B-4000, Belgium (3) Departamento de Física, Universidade Estadual Paulista, Bauru/SP, 17033-360, Brazil (4) Department of Physics, University of Antwerp, Groenenborgerlaan 171, B-2020, Belgium)
The ability to fabricate anisotropic superconducting layers a la carte is desired in technologies such as fluxon screening or removal in field-resilient devices, flux lensing in ultra-sensitive sensors, or in templates for imprinting magnetic structures in hybrid magnetic/superconducting multilayers. In this work, we demonstrate tailored superconductivity in polycrystalline niobium thin films exposed to femtosecond ultraviolet laser pulses. The samples exhibit significant changes in their superconducting properties, directly connected with the observed topography, crystallite geometry, and lattice parameter modifications. On the mesoscopic scale, quasi-parallel periodic ripple structures (about 260 nm of spatial period) gradually form on the film surface by progressively increasing the laser energy per pulse, Ep. This gives way to a stepwise increase of the critical current anisotropy and magnetic flux channeling effects along the ripples. As demonstrated in our resistive and inductive measurements, these superstructures determine the electromagnetic response of the sample within the regime dominated by flux-pinning. Time-dependent Ginzburg-Landau simulations corroborate the topographical origin of the customized anisotropy. Concurrently, intrinsic superconducting parameters (critical field and temperature) are moderately and isotropically depressed upon increasing Ep, as is the lattice parameter of Nb. These findings promote pulsed laser processing as a flexible, one-step, and scalable lithography-free technique for versatile surface functionalization in microelectronic superconducting technology.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci)
21 pages, 15 figures
Geometric flow of planar domain-wall loops
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-09-30 20:00 EDT
Pablo Domenichini, German Salazar, Alejandro B. Kolton
We investigate the geometric evolution of elastic domain-wall loops in two dimensions. Assuming an instantaneous, isotropic, and homogeneous arc-velocity response of the domain wall to external pressure and local signed curvature, we derive closed dynamical equations linking the enclosed area and loop perimeter for both linear and nonlinear arc-velocity response functions. This reduced description enables predictions for the dynamics of both spontaneous and externally driven domains-subjected to constant or alternating fields-within the time-dependent Ginzburg-Landau scalar $ \phi ^4$ model. In the linear response regime, where a non-crossing principle holds in the absence of external driving, we obtain exact results. In particular, we demonstrate that the relaxation rate of the total spontaneous magnetization becomes quantized for arbitrary initial conditions involving multiple, possibly nested, loops, with discrete jumps corresponding to individual loop collapse events. Under external driving, the avoidance principle breaks down due to sparse interactions between interfaces-either within a single loop or between multiple loops-leading to coalescence or splitting events that change the number of loops. A quantized geometrical observable involving the total area and perimeter is identified in this case as well, exhibiting discrete jumps both at interface interaction events and at individual loop collapses. We further use approximate area-perimeter relations to estimate the spontaneous collapse lifetimes of compact magnetic domains, as well as their dynamics under alternating-field-assisted collapse in disordered ultrathin magnetic films. Our predictions are compared with experimental observations in such systems.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech)
20 pages, 16 figures
Response to dynamic shape changes in suspensions of hard rectangles
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-30 20:00 EDT
While the autonomous assembly of hard nanoparticles with different shapes has been studied extensively both in experiment and simulations, little is known about systems where particle shape can be dynamically altered. DNA origami nanostructures offer an alternative route to synthesize nanoparticles that can change their shape on demand. Motivated by recent experiments, here we study the structure and dynamics of suspensions of hard squares in response to an elongation into a rectangle. Performing extensive hard-particle Monte Carlo simulations at constant volume and employing two protocols, we numerically analyze the collective diffusion and ordering during quenching and the subsequent relaxation to the new equilibrium state. We find that the cascading protocol, which mimics experimentally realized DNA origami, can become dynamically arrested due to the increase in effective packing fraction.
Soft Condensed Matter (cond-mat.soft)
Nanoscale Polar Landscapes in Quantum Paraelectric SrTiO3
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
Yang Zhang, Suk Hyun Sung, Nishkarsh Agarwal, Maya Gates, Cong Li, Pu Yu, Robert Hovden, Ismail El Baggari
SrTiO3 is a textbook quantum paraelectric, with ferroelectricity purportedly suppressed by quantum fluctuations of ionic positions down to the lowest temperatures. The precise real space structure of SrTiO3 at low temperature, however, has remained undefined despite decades of study. Here we directly image the low-temperature polar structure of quantum parelectric SrTiO3, using cryogenic scanning transmission electron microscopy down to 20 K. High resolution imaging reveals a spatially fluctuating landscape of nanoscale domains of finite polarization. The short-range polar domains first grow and self-organize into a periodic structure over tens of nanometers. However, the process reverses when entering the quantum paraelectric regime below 40 K and the periodically ordered polar nanodomains fragment into small clusters.
Materials Science (cond-mat.mtrl-sci)
The Limits of Inference in Complex Systems: When Stochastic Models Become Indistinguishable
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-30 20:00 EDT
Javier Aguilar, Miguel A. Muñoz, Sandro Azaele
Robust inference methods are essential for parameter estimation and model selection in stochastic modeling approaches, which provide interpretable frameworks for describing time series of complex phenomena. However, applying such methods is often challenging, as they typically demand either high-frequency observations or access to the model’s analytical solution, resources that are rarely available in practice. Here, we address these limitations by designing a novel Monte Carlo method based on full-path statistics and bridge processes, which optimize sampling efforts and performance even under coarse sampling. We systematically investigate how experimental design – particularly sampling frequency and dataset size – shapes inference accuracy, revealing optimal sampling regimes and the fundamental limits of model distinguishability. We validate our approach on four datasets – optical tweezers, human microbiome, topic mentions in social media, and forest population dynamics – where resolution-dependent limits to inference emerge, offering fresh insight into ongoing debates about the dominant sources of noise in these systems. Overall, this work shows how combining minimal stochastic models with path-inference tools and model selection can guide the experimental design of optimized strategies in data collection and clarify the boundaries of model-based understanding in complex systems.
Statistical Mechanics (cond-mat.stat-mech), Biological Physics (physics.bio-ph), Applications (stat.AP), Methodology (stat.ME)
A minimal model of self-organized clusters with phase transitions in ecological communities
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-30 20:00 EDT
Shing Yan Li, Mehran Kardar, Zhijie Feng, Washington Taylor
In complex ecological communities, species may self-organize into clusters or clumps where highly similar species can coexist. The emergence of such species clusters can be captured by the interplay between neutral and niche theories. Based on the generalized Lotka-Volterra model of competition, we propose a minimal model for ecological communities in which the steady states contain self-organized clusters. In this model, species compete only with their neighbors in niche space through a common interaction strength. Unlike many previous theories, this model does not rely on random heterogeneity in interactions. By varying only the interaction strength, we find an exponentially large set of cluster patterns with different sizes and combinations. There are sharp phase transitions into the formation of clusters. There are also multiple phase transitions between different sets of possible cluster patterns, many of which accumulate near a small number of critical points. We analyze such a phase structure using both numerical and analytical methods. In addition, the special case with only nearest neighbor interactions is exactly solvable using the method of transfer matrices from statistical mechanics. We analyze the critical behavior of these systems and make comparisons with existing lattice models.
Statistical Mechanics (cond-mat.stat-mech), Populations and Evolution (q-bio.PE)
23 pages, 8 figures
Extrapolation of Machine-Learning Interatomic Potentials for Organic and Polymeric Systems
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-30 20:00 EDT
Natalie E. Hooven, Arthur Y. Lin, Rose K. Cersonsky
Machine-Learning Interatomic Potentials (MLIPs) have surged in popularity due to their promise of expanding the spatiotemporal scales possible for simulating molecules with high fidelity. The accuracy of any MLIP is dependent on the data used for its training; thus, for large molecules, like polymers, where accurate training data is prohibitively difficult to obtain, it becomes necessary to pursue non-traditional methods to construct MLIPs, many of which are based on constructing MLIPs using smaller, analogous chemical systems. However, we have yet to understand the limits to which smaller molecules can be used as a proxy for extrapolating macromolecular energetics. Here, we provide a ``control study’’ for such experiments, exploring the ability of MLIP approaches to extrapolate between n=1-8 n-polyalkanes at identical conditions. Through Principal Covariates Classification, we quantitatively demonstrate how convergence in chemical environments between training and testing datasets coincides with an MLIP’s transferability. Additionally, we show how careful attention to the construction of an MLIP’s neighbor list can promote greater transferability when considering various levels of the energetic hierarchy. Our results establish a roadmap for how one can create transferable MLIPs for macromolecular systems without the prohibitive cost of constructing system-specific training data.
Soft Condensed Matter (cond-mat.soft), Chemical Physics (physics.chem-ph)
Two-dimensional THz spectroscopy in electronic systems: a many-body diagrammatic approach
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-30 20:00 EDT
Jacopo Fiore, Niccolò Sellati, Mattia Udina, Lara Benfatto
The term two-dimensional coherent spectroscopy (2DCS) usually refers to experimental setups where a coherently generated electric field in a sample is recorded over many runs as a function of two time variables: the delay $ \tau$ between two consequent excitation pulses and the time $ t$ over which the signal is emitted. While its implementation in the femtosecond time domain for studying vibrational molecular states has been developed for over two decades, its experimental application in the THz domain to interacting electronic systems remains in its infancy. This work provides a general theoretical framework for describing and interpreting 2DCS using a many-body language based on a perturbative diagrammatic expansion, as widely applied in linear spectroscopy. Focusing on centrosymmetric systems, we show that interpreting the 2D maps can be recast into two complementary problems. The first is the evaluation of a third-order response function to the gauge field. In the velocity gauge, this leads to semi-analytical expressions that both reduce computational complexity and assist in assigning spectral features to microscopic processes, as shown using a toy model of electrons undergoing a charge-density wave transition. The second is a careful treatment of multi-wave propagation effects, which, in bulk systems, can obscure the intrinsic nonlinear response, demonstrated here for soft superconducting Josephson plasmons. Our results provide a solid foundation for extending 2DCS to complex interacting systems and offer a flexible method to realistically model nonlinear responses across arbitrary spectral widths.
Superconductivity (cond-mat.supr-con), Other Condensed Matter (cond-mat.other), Strongly Correlated Electrons (cond-mat.str-el)
Collective transport efficiency of microswimmer swarms optimized by tactic run-tumble dynamics
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-30 20:00 EDT
Maggie Liu, Arnold J. T. M. Mathijssen
The collective motion of microorganisms and microrobots can be used for particle delivery, especially when guided by external magnetic fields, phototaxis, or chemotaxis. This cargo transport is enhanced significantly by hydrodynamic entrainment, where the surrounding fluid and any dissolved molecules or suspended cargo particles are dragged along with a collectively moving swarm. However, it remains unclear how this directed entrainment is affected by stochastic run-tumble motion, and how such motility patterns couple to particle dispersion. Here, we combine theory and simulations to compute the entrainment velocity and diffusivity for different degrees of swimmer directedness. Surprisingly, we find that the transport efficiency Péclet number, the ratio of advective to diffusive transport, is optimal for intermediate directedness values, so perfectly guided active suspensions perform worse than those with stochastic reorientations. These results could have implications for microrobotic drug delivery and nutrient transport in microbial environments.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
Eigenvector overlaps of sample covariance matrices with intersecting time periods
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-30 20:00 EDT
Volodymyr Riabov, Konstantin Tikhonov, Jean-Philippe Bouchaud
We compute exactly the overlap between the eigenvectors of two large empirical covariance ma- trices computed over intersecting time intervals, generalizing the results obtained previously for non-intersecting intervals. Our method relies on a particular form of Girko linearisation and ex- tended local laws. We check our results numerically and apply them to financial data.
Statistical Mechanics (cond-mat.stat-mech), Data Analysis, Statistics and Probability (physics.data-an), Mathematical Finance (q-fin.MF)
6 pages, 3 figures, supplementary material
Electrical resistivity of microstructural components in Al-Mg-Si alloys
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-30 20:00 EDT
Gautam Kumar, Amram Azulay, Omer Coriat, Hanna Bishara
Al-Mg-Si alloys are utilized in large scale electrical conduction applications thanks to their low density, high strength, and low electrical resistivity. The alloying elements, Mg and Si, are introduced to improve the mechanical strength; however, the formed defects also suppress electrical conductivity, adversely affecting the material performance. Here, we investigate the impact of alloying, heat treatment, and the corresponding microstructure, on the electrical resistivity of overaged alloys having 0.5-9.5 at. % solute. The crystal structure, composition, and microstructure are characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, electron backscatter diffraction, and scanning electron microscopy. The electrical resistivity of the microstructural components, i.e., the Al solid solution matrix and the Si and Mg2Si precipitates, are directly measured using a microscale four-point probe setup inside a scanning electron microscope. We find that the Al solid solution matrix is up to 15 % more resistive than pure Al, depending on the heat treatment rather than the composition, and that regions including Si or Mg2Si precipitates are equally resistive. Additionally, the bulk alloy resistivity, measured conventionally on a macroscopic length scale, increases linearly up to 60 % with increasing total solute concentration up to ~ 10 at. %. This study relates the electrical resistivity of Al-Mg-Si alloys, measured at microscopic and macroscopic length scales, with their microstructure and composition.
Materials Science (cond-mat.mtrl-sci)
19 Pages including Title and Graphical abstract, 7 figures
Coupling induced emergent topology in a two-leg fermionic ladder
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-09-30 20:00 EDT
Rajashri Parida, Biswajit Paul, Soumya Ranjan Padhi, Tapan Mishra
We investigate the ground state properties of spinless fermions on a two leg ladder, by allowing the nearest-neighbour hopping dimerization in one leg and uniform hopping in the other. In the non-interacting limit, we find that, at half-filling, the system exhibits robust topological behavior if the inter-leg hopping is allowed. As a result, a topological phase transition occurs as a function of the inter-leg hopping. When the inter-leg interaction is turned on, the topological phase survives, and we obtain an interaction induced topological phase transition as a function of interaction. Moreover, we show that for both the non-interacting and interacting cases, topological nature of the system survives even by altering the dimerization pattern in the dimerized leg, resulting in two topological phases of opposite character. Finally, we reveal that when uniform interactions are included on all the bonds of the ladder, the topological phase transitions to a symmetry-broken charge-density wave (CDW) phase.
Quantum Gases (cond-mat.quant-gas), Other Condensed Matter (cond-mat.other), Strongly Correlated Electrons (cond-mat.str-el)
10pages, 15 figures
Momentum-resolved two-dimensional spectroscopy as a probe of nonlinear quantum field dynamics
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-09-30 20:00 EDT
Duilio De Santis, Alex Gómez Salvador, Nataliia Bazhan, Sebastian Erne, Maximilian Prüfer, Claudio Guarcello, Davide Valenti, Jörg Schmiedmayer, Eugene Demler
Emergent collective excitations constitute a hallmark of interacting quantum many-body systems, yet in solid-state platforms their study has been largely limited by the constraints of linear-response probes and by finite momentum resolution. We propose to overcome these limitations by combining the spatial resolution of ultracold atomic systems with the nonlinear probing capabilities of two-dimensional spectroscopy (2DS). As a concrete illustration, we analyze momentum-resolved 2DS of the quantum sine-Gordon model describing the low energy dynamics of two weakly coupled one-dimensional Bose-Einstein condensates. This approach reveals distinctive many-body signatures, most notably asymmetric cross-peaks reflecting the interplay between isolated ($ B_2$ breather) and continuum ($ B_1$ pair) modes. The protocol further enables direct characterization of anharmonicity and disorder, establishing momentum-resolved 2DS as both a powerful diagnostic for quantum simulators and a versatile probe of correlated quantum matter.
Quantum Gases (cond-mat.quant-gas), Pattern Formation and Solitons (nlin.PS), Quantum Physics (quant-ph)
Main text: 8 pages, 4 figures
Guided Diffusion for the Discovery of New Superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-30 20:00 EDT
Pawan Prakash, Jason B. Gibson, Zhongwei Li, Gabriele Di Gianluca, Juan Esquivel, Eric Fuemmeler, Benjamin Geisler, Jung Soo Kim, Adrian Roitberg, Ellad B. Tadmor, Mingjie Liu, Stefano Martiniani, Gregory R. Stewart, James J. Hamlin, Peter J. Hirschfeld, Richard G. Hennig
The inverse design of materials with specific desired properties, such as high-temperature superconductivity, represents a formidable challenge in materials science due to the vastness of chemical and structural space. We present a guided diffusion framework to accelerate the discovery of novel superconductors. A DiffCSP foundation model is pretrained on the Alexandria Database and fine-tuned on 7,183 superconductors with first principles derived labels. Employing classifier-free guidance, we sample 200,000 structures, which lead to 34,027 unique candidates. A multistage screening process that combines machine learning and density functional theory (DFT) calculations to assess stability and electronic properties, identifies 773 candidates with DFT-calculated $ T_\mathrm{c}>5$ K. Notably, our generative model demonstrates effective property-driven design. Our computational findings were validated against experimental synthesis and characterization performed as part of this work, which highlighted challenges in sparsely charted chemistries. This end-to-end workflow accelerates superconductor discovery while underscoring the challenge of predicting and synthesizing experimentally realizable materials.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci), Artificial Intelligence (cs.AI)
13 pages, 5 figures, 1 table