CMP Journal 2025-05-30
Statistics
Physical Review Letters: 4
Physical Review X: 2
arXiv: 61
Physical Review Letters
Experimental Single-Photon Quantum Key Distribution Surpassing the Fundamental Weak Coherent-State Rate Limit
Research article | Quantum communication | 2025-05-29 06:00 EDT
Yang Zhang, Xing Ding, Yang Li, Likang Zhang, Yong-Peng Guo, Gao-Qiang Wang, Zhen Ning, Mo-Chi Xu, Run-Ze Liu, Jun-Yi Zhao, Geng-Yan Zou, Hui Wang, Yuan Cao, Yu-Ming He, Cheng-Zhi Peng, Yong-Heng Huo, Sheng-Kai Liao, Chao-Yang Lu, Feihu Xu, and Jian-Wei Pan
Single-photon-source-based quantum key distribution surpasses the fundamental secret key rate limit imposed by weak coherent states.
Phys. Rev. Lett. 134, 210801 (2025)
Quantum communication, Quantum communication, protocols & technology, Quantum cryptography, Single photon sources
Detectable and Defect-Free Dark Photon Dark Matter
Research article | Dark matter | 2025-05-29 06:00 EDT
David Cyncynates and Zachary J. Weiner
Ultralight dark photons are compelling dark matter candidates, but their allowed kinetic mixing with the standard model photon is severely constrained by requiring that the dark photons do not collapse into a cosmic string network in the early Universe. Direct detection in minimal production scenarios for dark photon dark matter is strongly limited, if not entirely excluded; discovery of sub-meV dark photon dark matter would therefore point to a nonminimal dark sector. We describe a model that evades such constraints, capable of producing cold dark photons in any parameter space accessible to future direct detection experiments. The associated production dynamics yield additional signatures in cosmology and small-scale structure, allowing for possible positive identification of this particular class of production mechanisms.
Phys. Rev. Lett. 134, 211002 (2025)
Dark matter, Particle dark matter, Hypothetical gauge bosons
Three-Dimensional Valley Hall Phases in Phononic Crystals
Research article | Phononic crystals | 2025-05-29 06:00 EDT
Riyi Zheng, Jialuo Liang, Junpeng Wu, Jiuyang Lu, Weiyin Deng, Xueqin Huang, Manzhu Ke, and Zhengyou Liu
Three dimensional valley Hall phases form in phononic crystals, revealed as topological surface states protected by 3-tuple valley Chern numbers.
Phys. Rev. Lett. 134, 216601 (2025)
Phononic crystals, Topological insulators, Topological phases of matter, Valley degrees of freedom, 2-dimensional systems
Unravelling the Surface Local Spin Dynamics in Magnetic Nanoparticles by Means of NMR Relaxometry
Research article | Magnetism | 2025-05-29 06:00 EDT
M. Basini, M. Mariani, Q. L. Vuong, Y. Gossuin, S. Slimani, G. Singh, D. Peddis, and A. Lascialfari
NMR relaxometry reveals the surface spin dynamics in a magnetic hollow nanosphere showing that the technique can single out different correlation times in a system composed of more than one electronic spin reservoir.
Phys. Rev. Lett. 134, 216703 (2025)
Magnetism, Spin dynamics, Magnetic nanoparticles, Nuclear magnetic resonance relaxation rate
Physical Review X
Electrically Driven Cascaded Photon Emission in a Single Molecule
Research article | Charge dynamics | 2025-05-29 06:00 EDT
Katharina Kaiser, Anna Rosławska, Michelangelo Romeo, Fabrice Scheurer, Tomáš Neuman, and Guillaume Schull
Injecting electrons into a single molecule with atomic precision reveals a cascaded photon emission process, demonstrating potential for a controllable, electrically powered quantum light source.
Phys. Rev. X 15, 021072 (2025)
Charge dynamics, Electroluminescence, Electronic structure of atoms & molecules, Electronic transitions, Excitons, Nanophotonics, Optoelectronics, Photon statistics, Photonics, Quantum optics, Single photon sources, Molecules, Tunnel junctions, Scanning tunneling microscopy, Single-photon detectors
Hybrid Quantum-Classical Stochastic Approach to Dissipative Spin-Boson Models
Research article | Dissipative dynamics | 2025-05-29 06:00 EDT
Naushad A. Kamar and Mohammad Maghrebi
A new method to simulate spin-boson systems under noise uses classical and quantum stochastic equations, turning dissipation into a tool for exactly capturing quantum dynamics in realistic, noisy quantum devices.
Phys. Rev. X 15, 021073 (2025)
Dissipative dynamics, Open quantum systems, Quantum simulation, Complex Langevin dynamics, Quantum master equation, Spin-boson model, Stochastic analysis
arXiv
Anderson transition in high dimension: comments to arXiv:2403.01974
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-05-30 20:00 EDT
I. M. Suslov (<a href=”http://P.L.Kapitza“ rel=”external noopener nofollow” class=”link-external link-http”>this http URL</a> Institute for Physical Problems, Moscow, Russia)
In the recent submission arXiv:2403.01974, Altshuler et al suggested a new approach to the Anderson transition in high dimensions. The main idea consists in the use of the branching graphs instead of high-dimensional lattices: it does not look very convincing, but we do not want to stress this point. Since the authors welcome comments, we put forward a lot of objections to their exposition of the general situation. The arising hypothesis is given in the end.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
Latex, 4 pages
Localized Triplons and Site Stuffing in the Quantum Dimer Magnet BiYbGeO$_5$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-30 20:00 EDT
Rachit Kapoor, D. Yahne, V.O. Garlea, G. Hester
Thermodynamic and muon spin-relaxation measurements have recently highlighted BiYbGeO$ _5$ as a new example of a rare-earth-based quantum dimer magnet with isolated Yb$ ^{3+}$ spin-$ \frac{1}{2}$ dimers. However, direct spectroscopic evidence of the triplet excitations and measurements of the structural disorder are lacking. In this work, polycrystalline BiYbGeO$ 5$ was synthesized using conventional high-temperature solid-state methods and investigated via high-resolution neutron powder diffraction and inelastic neutron scattering. Diffraction measurements down to 58 mK reveal no signatures of magnetic order and indicate that nearly 20% of Yb$ ^{3+}$ sites are replaced by non-magnetic Bi$ ^{3+}$ , introducing significant structural disorder. Inelastic neutron scattering shows dispersionless triplon excitations, consistent with localized, non-interacting spin dimers. Fits to the triplet excitation spectrum identify an XXZ-type anisotropic exchange with $ J{XX}$ = 0.11(2) meV and $ J_Z = 0.15(1)$ meV. These findings establish BiYbGeO$ _5$ as a structurally disordered but magnetically well-isolated quantum dimer system, providing a model platform for studying the resilience of entangled spin states to site dilution.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
6 pages, 5 figures
Markovian dissipation can stabilize a (localization) quantum phase transition
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-05-30 20:00 EDT
Naushad A. Kamar, Mostafa Ali, Mohammad Maghrebi
Quantum phase transitions are a cornerstone of many-body physics at low temperatures but have remained elusive far from equilibrium. Driven open quantum systems – a prominent non-equilibrium platform where coherent dynamics competes with Markovian dissipation from the environment – often exhibit an effective classical behavior. In this work, we present a nontrivial quantum phase transition that is stabilized, rather than destroyed, by Markovian dissipation. We consider a variant of the paradigmatic spin-boson model where the spin is driven and bosons are subject to Markovian loss proportional to frequency (hence, vanishing at low frequencies). We show that the steady state exhibits a localization phase transition where the spin’s dynamics is frozen, to be contrasted with the ground-state transition in the absence of dissipation. Furthermore, this transition occurs when the steady state becomes pure. The latter is not simply a dark state of dissipation but rather emerges from a nontrivial renormalization of the spin dynamics by low-frequency bosonic modes. Our work provides a nontrivial example where quantumness, typically reserved for ground states, also emerges in dynamical settings, with potential applications in quantum computation.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
Quantum multicriticality and emergent symmetry in Dirac systems with two order parameters at three-loop order
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-30 20:00 EDT
Max Uetrecht, Igor F. Herbut, Michael M. Scherer, Emmanuel Stamou, Tom Steudtner
Two-dimensional materials with interacting Dirac excitations can host quantum multicritical behavior near the phase boundaries of the semimetallic and two-ordered phases. We study such behavior in Gross–Neveu–Yukawa field theories where $ N_f$ flavors of Dirac fermions are coupled to two order-parameter fields with $ SO(N_A)$ and $ SO(N_B)$ symmetry, respectively. To that end, we employ the perturbative renormalization group up to three-loop order in $ 4-\epsilon$ spacetime dimensions. We distinguish two key scenarios: (i) The two orders are compatible as characterized by anticommuting mass terms, and (ii) the orders are incompatible. For the first case, we explore the stability of a quantum multicritical point with emergent $ SO(N_A!+!N_B)$ symmetry. We find that the stability is controlled by increasing the number of Dirac fermion flavors. Moreover, we extract the series expansion of the leading critical exponents for the chiral $ SO(4)$ and $ SO(5)$ models up to third order in $ \epsilon$ . Notably, we find a tendency towards rapidly growing expansion coefficients at higher orders, rendering an extrapolation to $ \epsilon=1$ difficult. For the second scenario, we study a model with $ SO(4) \simeq SO(3) \times SO(3)$ symmetry, which was recently suggested to describe criticality of antiferromagnetism and superconductivity in Dirac systems. However, it was also argued that a physically admissible renormalization-group fixed point only exists for $ N_f$ above a critical number $ N_{c}^>$ . We determine the corresponding series expansion at three-loop order as $ N_{c}^>\approx 16.83-7.14\epsilon-7.12\epsilon^2$ . This suggests that the physical choice of $ N_f=2$ may be a borderline case, where true criticality and pseudocriticality, as induced by fixed-point annihilation, are extremely challenging to distinguish.
Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Theory (hep-th)
17 pages, 3 figures
Kekulé order from diffuse nesting near higher-order Van Hove points
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-30 20:00 EDT
Jonas Beck, Jonathan Bodky, Matteo Dürrnagel, Ronny Thomale, Julian Ingham, Lennart Klebl, Hendrik Hohmann
Translation symmetry-breaking order is assumed to be suppressed by the lack of Fermi surface nesting near certain higher-order Van Hove singularities (HOVHS). We show the anisotropic band-flattening inherent to such HOVHS, combined with broadening of the Fermi surface due to elevated critical temperatures, results in the Fermi surface becoming approximately nested at a wavevector unrelated to the precise shape of the Fermi surface - leading to a $ \sqrt{3}\times\sqrt{3}$ Kekulé density wave formation. The effect is demonstrated using unbiased renormalization group calculations for a model of the breathing kagome lattice. Our mechanism - termed diffuse nesting - represents an entirely new notion in the study of Fermi surface instabilities.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Frictional Contact Network in Dense Suspension Flow
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-30 20:00 EDT
Shweta Sharma, Abhishek Sharma, Abhinendra Singh
Dense particulate suspensions often exhibit a dramatic increase in viscosity in response to external deformation. This shear thickening behavior has been related to a transition from lubricated, unconstrained pairwise motion to a frictional contact network (FCN) at high stresses. Here, we study the characteristics of the FCN formed during shear thickening to investigate the role of constraints, emphasizing the impact of resistance to gear-like rolling. We contrast the FCN formed by sliding friction alone with that formed by particles with sliding and rolling constraints. Particles with sliding constraints only form a highly interconnected network with primary force chains in the compressive direction, which requires orthogonal support from other force chains. However, orthogonal support is not required for mechanical stability when particles have both sliding and rolling constraints. In addition, the force chains appear linear and longer, reducing the jamming volume fraction for rough/faceted particles. Finally, we propose a novel mechanical stability picture for rough/faceted particles with sliding and rolling constraints, which is crucial for understanding the flow behavior of real-life suspensions.
Soft Condensed Matter (cond-mat.soft)
19 pages, 12 figures
Ultra-long-living magnons in the quantum limit
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-30 20:00 EDT
Rostyslav O. Serha, Kaitlin H. McAllister, Fabian Majcen, Sebastian Knauer, Timmy Reimann, Carsten Dubs, Gennadii A. Melkov, Alexander A. Serga, Vasyl S. Tyberkevych, Andrii V. Chumak, Dmytro A. Bozhko
Coherence time is the property of a quantum system that determines how long a state can hold quantum information. This parameter is directly bound to their lifetime in solid-state systems, where quantum information could be stored in quasiparticles. For decades, quasiparticles associated with magnetization order disturbance - magnons, had reported lifetimes below one microsecond at gigahertz frequencies, restricting their use as a quantum information carrier. Here, we report on the observation of short-wavelength magnons with lifetimes exceeding 18{\mu}s at millikelvin temperatures. The experiment has been performed in an ultra-pure single-crystal Yttrium Iron Garnet sphere in a wide range of temperatures from ambient down to 30 mK. Our results open doors for using magnons as data carriers in modern solid-state quantum computing platforms.
Materials Science (cond-mat.mtrl-sci), Quantum Physics (quant-ph)
Molecular anyons in fractional quantum Hall effect
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-30 20:00 EDT
One of the profound consequences of the fractional quantum Hall (FQH) effect is the notion of fractionally charged anyons. In spite of extensive experimental study, puzzles remain, however. For example, both shot-noise and Aharonov-Bohm interference measurements sometimes report a charge that is a multiple of the elementary charge. We report here high-precision microscopic calculations that reveal the surprising result that the FQH anyons often bind together into stable clusters, which we term molecular anyons. This is counterintuitive, given that the elementary anyons carry the same charge and are therefore expected to repel one another. The number of anyons in a cluster, its binding energy and its size depend sensitively on the parent FQH state and the interaction between electrons (which is experimentally tunable, e.g., by varying the quantum well width). Our calculations further suggest that the charge-$ 1/4$ non-Abelian anyons of the $ 5/2$ FQH state may also bind to form charge-$ 1/2$ Abelian clusters. The existence of molecular anyons not only can provide a natural explanation for the observed charges, but also leads to a host of new predictions for future experiments and invites a re-analysis of many past ones.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
PdNeuRAM: Forming-Free, Multi-Bit Pd/HfO2 ReRAM for Energy-Efficient Computing
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-30 20:00 EDT
Erbing Hua, Theofilos Spyrou, Majid Ahmadi, Abdul Momin Syed, Hanzhi Xun, Laurentiu Braic, Ewout van der Veer, Nazek Elatab, Anteneh Gebregiorgis, Georgi Gaydadjiev, Beatriz Noheda, Said Hamdioui, Ryoichi Ishihara, Heba Abunahla
Memristor technology shows great promise for energy-efficient computing, yet it grapples with challenges like resistance drift and inherent variability. For filamentary Resistive RAM (ReRAM), one of the most investigated types of memristive devices, the expensive electroforming step required to create conductive pathways results in increased power and area overheads and reduced endurance. In this study, we present novel HfO2-based forming-free ReRAM devices, PdNeuRAM, that operate at low voltages, support multi-bit functionality, and display reduced variability. Through a deep understanding and comprehensive material characterization, we discover the key process that allows this unique behavior: a Pd-O-Hf configuration that capitalizes on Pd innate affinity for integrating into HfO2. This structure actively facilitates charge redistribution at room temperature, effectively eliminating the need for electroforming. Moreover, the fabricated ReRAM device provides tunable resistance states for dense memory and reduces programming and reading energy by 43% and 73%, respectively, using spiking neural networks (SNN). This study reveals novel mechanistic insights and delineates a strategic roadmap for the realization of power-efficient and cost-effective ReRAM devices.
Materials Science (cond-mat.mtrl-sci), Image and Video Processing (eess.IV)
32 pages, 6 figures in main text and 7 figures in supporting information
Symmetry tuning topological states of an axion insulator with noncollinear magnetic order
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-30 20:00 EDT
S. X. M. Riberolles, A. M. Nedić, B. Kuthanazhi, F. Ye, S. L. Bud’ko, P. C. Canfield, R. J. McQueeney, Junyeong Ahn, V. L. Quito, T. V. Trevisan, L. L. Wang, P. P. Orth, B. G. Ueland
Topological properties of quantum materials are intimately related to symmetry. Here, we tune the magnetic order of the axion insulator candidate EuIn$ _2$ As$ _2$ from its broken-helix ground state to the field-polarized phase by applying an in-plane magnetic field. Using results from neutron diffraction and magnetization measurements with ab inito theory and symmetry analysis, we determine how the field tunes the magnetic symmetry within individual magnetic domains and examine the resulting changes to the topological surface states and hinge states existing on edges shared by certain surfaces hosting gapped Dirac states. We predict field-tunable complex and domain-specific hinge-state patterns, with some crystal surfaces undergoing a field-induced topological phase transition. We further find that domain walls have pinned hinge states when intersecting certain crystal surfaces, providing another channel for tuning the chiral-charge-transport pathways.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Selenization of V2O5/WO3 Bilayers for Tuned Optoelectronic Response of WSe2 Films
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-30 20:00 EDT
Abhishek Bajgain, Santu Prasad Jana, Alexander Samokhvalov, Thomas Parker, John Derek Demaree, Ramesh C. Budhani
Scalable and controlled doping of two-dimensional transition metal dichalcogenides is essential for tuning their electronic and optoelectronic properties. In this work, we demonstrate a robust approach for substitution of vanadium in tungsten diselenide (WSe$ _2$ ) via the selenization of pre-deposited V$ _2$ O$ _5$ /WO$ _3$ thin films. By adjusting the thickness of the vanadium oxide layer, the V concentration in W$ _{1-x}$ V$ _x$ Se$ _2$ is systematically varied. Electrical measurements on field-effect transistors reveal a substantial enhancement in hole conduction, with drain current increasing by nearly three orders of magnitude compared to undoped WSe$ _2$ . Temperature-dependent electrical resistivity indicates a clear insulator-to-metal transition with increasing V content, likely due to band structure modifications. Concurrently, the photoconductive gain decreases, suggesting enhanced recombination and charge screening effects. These results establish vanadium doping via selenization of V$ _2$ O$ _5$ /WO$ _3$ films as a scalable strategy for modulating the transport and photoresponse of WSe$ _2$ , offering promising implications for wafer-scale optoelectronic device integration.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
7 pages,5 figures
Enhanced Stability and Linearly Polarized Emission from CsPbI3 Perovskite Nanoplatelets through A-site Cation Engineering
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-30 20:00 EDT
Woo Hyeon Jeong, Junzhi Ye, Jongbeom Kim, Rui Xu, Xinyu Shen, Chia-Yu Chang, Eilidh L. Quinn, Myoung Hoon Song, Peter Nellist, Henry J. Snaith, Yunwei Zhang, Bo Ram Lee, Robert L. Z. Hoye
The anisotropy of perovskite nanoplatelets (PeNPLs) opens up many opportunities in optoelectronics, including enabling the emission of linearly polarized light. But the limited stability of PeNPLs is a pressing challenge, especially for red-emitting CsPbI3. Herein, we address this limitation by alloying FA into the perovskite cuboctahedral site. Unlike Cs/FA alloying in bulk thin films or nonconfined nanocubes, FA incorporation in nanoplatelets requires meticulous control over the reaction conditions, given that nanoplatelets are obtained in kinetically-driven growth regimes instead of thermodynamically-driven conditions. Through in-situ photoluminescence (PL) measurements, we find that excess FA leads to uncontrolled growth, where phase-impurities and nanoplatelets of multiple thicknesses co-exist. Restricting the FA content to up to 25% Cs substitution enables monodisperse PeNPLs, and increases the PL quantum yield (from 53% to 61%), exciton lifetime (from 18 ns to 27 ns), and stability in ambient air (from ~2 days to >7 days) compared to CsPbI3. This arises due to hydrogen bonding between FA and the oleate and oleylammonium ligands, anchoring them to the surface to improve optoelectronic properties and stability. The reduction in non-radiative recombination, improvement in the nanoplatelet aspect ratio, and higher ligand density lead to FA-containing PeNPLs more effectively forming edge-up superlattices, enhancing the PL degree of linear polarization from 5.1% (CsPbI3) to 9.4% (Cs0.75FA0.25PbI3). These fundamental insights show how the stability limitations of PeNPLs could be addressed, and these materials grown more precisely to improve their performance as polarized light emitters, critical for utilizing them in next-generation display, bioimaging and communications applications.
Materials Science (cond-mat.mtrl-sci)
19 pages, 5 figures
Nanoscale quantum imaging of field-free deterministic switching of a chiral antiferromagnet
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-30 20:00 EDT
Jingcheng Zhou, Senlei Li, Chuangtang Wang, Hanshang Jin, Stelo Xu, Zelong Xiong, Carson Jacobsen, Kenji Watanabe, Takashi Taniguchi, Valentin Taufour, Liuyan Zhao, Hua Chen, Chunhui Rita Du, Hailong Wang
Recently, unconventional spin-orbit torques (SOTs) with tunable spin generation open new pathways for designing novel magnetization control for cutting-edge spintronics innovations. A leading research thrust is to develop field-free deterministic magnetization switching for implementing scalable and energy favorable magnetic recording and storage applications, which have been demonstrated in conventional ferromagnetic and antiferromagnetic material systems. Here we extend this advanced magnetization control strategy to chiral antiferromagnet Mn3Sn using spin currents with out-of-plane canted polarization generated from low-symmetry van der Waals (vdW) material WTe2. Numerical calculations suggest that damping-like SOT of spins injected perpendicular to the kagome plane of Mn3Sn serves as a driving force to rotate the chiral magnetic order, while the field-like SOT of spin currents with polarization parallel to the kagome plane provides the bipolar deterministicity to the magnetic switching. We further introduce scanning quantum microscopy to visualize nanoscale evolutions of Mn3Sn magnetic domains during the field-free switching process, corroborating the exceptionally large magnetic switching ratio up to 90%. Our results highlight the opportunities provided by hybrid SOT material platforms consisting of noncollinear antiferromagnets and low-symmetry vdW spin source materials for developing next-generation, transformative spintronic logic devices.
Materials Science (cond-mat.mtrl-sci)
Emergence of Transverse Dielectric Response in Ferroelectric Dielectric Heterostructures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-30 20:00 EDT
Fernando Gómez-Ortiz, Ramamoorthy Ramesh, Javier Junquera
We report the emergence of a transverse dielectric response in PbTiO$ _{3}$ /SrTiO$ _{3}$ superlattices hosting polar vortex structures. Using second-principles simulations, we find that an electric field applied along one direction induces significant local polarization responses along orthogonal directions, with magnitudes approaching half that of the diagonal susceptibility components. These off-diagonal responses are strongly dependent on the topology of the vortex structure and can be deterministically tuned or even reversed via homogeneous electric fields or epitaxial strain. Notably, the transverse susceptibilities become comparable to the diagonal components during a field- or strain-induced transition to a polarization wave state. This discovery opens avenues for engineering reconfigurable nanoscale dielectric responses in topologically textured ferroelectric systems.
Materials Science (cond-mat.mtrl-sci)
Spectrum Selective Interfaces and Materials towards Non-photothermal Saltwater Evaporation: Demonstration with a White Ceramic Wick
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-30 20:00 EDT
Navindra D. Singh, James Leung, Ji Feng, Alma K. González-Alcalde, Arial Tolentino, David Tuft, Juchen Guo, Luat T. Vuong
Most solar desalination efforts are photothermal: they evaporate water with black'' materials that absorb as much sunlight as possible. Such brine-boiling’’ methods are severely limited by the high thermal mass of water, i.e., its capacity to store and release heat. Here, we study the light-enhanced evaporation by a hard, white, aluminum nitride wick, which reveals a route to selectively target salt-water bonds instead of bulk heating. Evaporation rates dramatically increase with short-wavelength illumination. Violet-light illumination achieves 4-10x higher evaporation enhancement compared to orange and IR light. Our results identify a light-driven, spectrum-selective path to non-photothermal saltwater evaporation and opportunities to employ ceramic wicks for salt harvesting. Such low-cost, low-energy desalination systems would reduce the heat island effects of traditional solar technologies and contribute to new cooling technologies where drought is also a concern.
Materials Science (cond-mat.mtrl-sci), Optics (physics.optics)
15 pages, 5 figures, submitted to ACS ES&T, 68 references
Telecom quantum dots on GaAs substrates as integration-ready high performance single-photon sources
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-30 20:00 EDT
Beatrice Costa, Bianca Scaparra, Xiao Wei, Hubert Riedl, Gregor Koblmüller, Eugenio Zallo, Jonathan Finley, Lukas Hanschke, Kai Müller
The development of deterministic single photon sources emitting in the telecommunication bands is a key challenge for quantum communication and photonic quantum computing. Here, we investigate the optical properties and single-photon emission of molecular beam epitaxy grown semiconductor quantum dots emitting in the telecom O- and C- bands. The quantum dots are embedded in a InGaAs matrix with fixed indium content grown on top of a compositionally graded InGaAs buffer. This structure allows for the future implementation of electrically contacted nanocavities to enable high-quality and bright QD emission. In detailed optical characterizations we observe linewidths as low as $ 50 \mu$ eV, close to the spectrometer resolution limit, low fine structure splittings close to $ 10 \mu$ eV, and $ g^{(2)} (0)$ values as low as $ 0.08$ . These results advance the current performance metrics for MBE-grown quantum dots on GaAs substrates emitting in the telecom bands and showcase the potential of the presented heterostructures for further integration into photonic devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
8 pages, 4 figures
Understanding and Embracing Imperfection in Physical Learning Networks
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-05-30 20:00 EDT
Sam Dillavou, Marcelo Guzman, Andrea J. Liu, Douglas J. Durian
Performing machine learning (ML) with analog instead of digital signals offers advantages in speed and energy efficiency, but component and measurement imperfections can make nonlinear analog networks difficult to train. As a result, most schemes involve a precise digital model, either to train alone or in tandem with experiments. Here we take a different perspective: working in the analog domain, we characterize the consequences of the inherent imperfection of a physical learning system and, ultimately, overcome them. We train an analog network of self-adjusting resistors – a contrastive local learning network (CLLN) – for multiple tasks, and observe limit cycles and characteristic scaling behaviors absent in `perfect’ systems. We develop an analytical model that captures these phenomena by incorporating an uncontrolled but deterministic bias into the learning process. Our results suggest that imperfections limit precision and erase memory of previous tasks by continuously modifying the underlying representation of all learned tasks, akin to representational drift in the brain. Finally, we introduce and demonstrate a system-agnostic training method that greatly suppresses these effects. Our work points to a new, scalable approach in analog learning, one that eschews precise modeling and instead thrives in the mess of real systems.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Soft Condensed Matter (cond-mat.soft)
Spontaneous vortex lattice due to orbital magnetization in valley polarized superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-30 20:00 EDT
In this work, we study the spontaneous formation of a vortex lattice in two-dimensional valley polarized superconductors due to orbital magnetization. The screening of magnetic field is weak for two-dimension superconductors, allowing for the magnetic flux associated with vortices to penetrate deep into the superconducting region. The Zeeman coupling between orbital magnetization and magnetic fields associated with vortices leads to the formation of a vortex lattice, once the vortex self-energy is lower than the Zeeman energy. We study the phase diagram and the vortex lattice configuration, and discuss the consequences of the vortex lattice formation in various experimental setups.
Superconductivity (cond-mat.supr-con)
Emergent universal long-range structure in random-organizing systems
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-30 20:00 EDT
Satyam Anand, Guanming Zhang, Stefano Martiniani
Self-organization through noisy interactions is ubiquitous across physics, mathematics, and machine learning, yet how long-range structure emerges from local noisy dynamics remains poorly understood. Here, we investigate three paradigmatic random-organizing particle systems drawn from distinct domains: models from soft matter physics (random organization, biased random organization) and machine learning (stochastic gradient descent), each characterized by distinct sources of noise. We discover universal long-range behavior across all systems, namely the suppression of long-range density fluctuations, governed solely by the noise correlation between particles. Furthermore, we establish a connection between the emergence of long-range order and the tendency of stochastic gradient descent to favor flat minima – a phenomenon widely observed in machine learning. To rationalize these findings, we develop a fluctuating hydrodynamic theory that quantitatively captures all observations. Our study resolves long-standing questions about the microscopic origin of noise-induced hyperuniformity, uncovers striking parallels between stochastic gradient descent dynamics on particle system energy landscapes and neural network loss landscapes, and should have wide-ranging applications – from the self-assembly of hyperuniform materials to ecological population dynamics and the design of generalizable learning algorithms.
Soft Condensed Matter (cond-mat.soft), Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech)
27 pages, 8 figures
Non Markovian electron Brownian motion with radiation reaction force
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-30 20:00 EDT
Juan Francisco García-Camacho, Oliver Contreras-Vergara, Norma Sánchez-Salas, Gonzalo Ares de Parga, José Inés Jiménez-Aquino
In this work, we study non-Markovian electronic plasma diffusion from a classical point of view, taking into account the effects of the radiation reaction force. The electron Brownian motion is described by a Generalized Langevin Equation (GLE) characterized by an Ornstein-Uhlenbeck-type friction memory kernel. To take into account the effects of the radiation reaction force, an effective memory time which accounts for the thermal interaction of the Brownian particle with its surroundings is proposed. This effective memory time is defined as tauef equal tau minus tau0 less than 0, where the memory time tau accounts for the collision time between electrons in a Brownian motion-like manner, and tau0 is due to the interaction with the radiation reaction force. Under these conditions, the GLE can be transformed into a stochastic Abraham-Lorentz-like equation, which is analytically solved without violation of causality. The theoretical results will be compared with the numerical simulation.
Statistical Mechanics (cond-mat.stat-mech)
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Diverse edge states of nanoribbons and excitonic insulator states of the monolayer Ta2Ni3Te5
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-30 20:00 EDT
Hong Tang, Jiang Wei, Gabor I. Csonka, Adrienn Ruzsinszky
Ta2Ni3Te5, a layered transition metal chalcogenide with quasi-one-dimensional electronic states, exhibits rich topological and correlated phenomena. Using first-principles calculations, we explore Ta2Ni3Te5 nanoribbons, demonstrating tunable electronic and magnetic properties-ranging from metallic to semimetallic and semiconducting (band gaps of 29.7-60.8 meV), and from ferromagnetic to antiferromagnetic-controlled by edge (Ni or Ta), ribbon width, and H/F saturation. Additionally, GW and Bethe-Salpeter equation (BSE) calculations, complemented by metaGGA-based modified BSE, reveal that the Ta2Ni3Te5 monolayer is an excitonic insulator, with an exciton binding energy exceeding its band gap. These diverse properties position Ta2Ni3Te5 nanoribbons and monolayers as promising candidates for nanoelectronics, spintronics, and optoelectronics, motivating further experimental exploration.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
10 Figures
Probing disorder-induced Fisher information matrix and Cramér-Rao bound by STM
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-30 20:00 EDT
The electronic local density of states of solids, if normalized correctly, represents the probability density that the electron at a specific position has a particular energy. Because this probability density can vary in space in disordered systems, we propose that one can either treat the energy as a random variable and position as an external parameter to construct a real space Fisher information matrix, or treat the position as a random variable and energy as an external parameter to construct an energy space Fisher information, both quantify the variation of local density of states caused by the disorder. The corresponding Cramér-Rao bounds in these two scenarios set a limit on the energy variance and the position variance of electrons, respectively, pointing to new interpretations of STM measurements. Our formalism thus bring the notion of information geometry into STM measurements, as demonstrated explicitly by lattice models of metals and topological insulators.
Strongly Correlated Electrons (cond-mat.str-el), Disordered Systems and Neural Networks (cond-mat.dis-nn)
8 pages, 3 figures
Parametric Instability in Discrete Models of Spatiotemporally Modulated Materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-30 20:00 EDT
We investigate the phenomenon of parametric instability in discrete models of spatiotemporally modulated materials. These materials are celebrated in part because they exhibit nonreciprocal transmission characteristics. However, parametric instability may occur for strong modulations, or occasionally even at very small modulation amplitudes, and prevent the safe operation of spatiotemporally modulated devices due to an exponential growth in the response amplitude. We use Floquet theory to conduct a detailed computational investigation of parametric instability. We explore the roles of modulation parameters (frequency, amplitude, wavenumber), the number of modulated units, and damping on the stability of the system. We highlight the pivotal role of spatial modulation in parametric instability, a feature that is predominantly overlooked in this context. We use the perturbation method to obtain analytical expressions for modulation frequencies at which the response becomes unstable. We hope that our findings enable and inspire new applications of spatiotemporally modulated materials that operate at higher amplitudes.
Materials Science (cond-mat.mtrl-sci), Dynamical Systems (math.DS), Applied Physics (physics.app-ph)
Machine Learning Framework for Characterizing Processing-Structure Relationship in Block Copolymer Thin Films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-30 20:00 EDT
Bradley Lamb, Saroj Upreti, Yunfei Wang, Daniel Struble, Chenhui Zhu, Guillaume Freychet, Xiaodan Gu, Boran Ma
The morphology of block copolymers (BCPs) critically influences material properties and applications. This work introduces a machine learning (ML)-enabled, high-throughput framework for analyzing grazing incidence small-angle X-ray scattering (GISAXS) data and atomic force microscopy (AFM) images to characterize BCP thin film morphology. A convolutional neural network was trained to classify AFM images by morphology type, achieving 97% testing accuracy. Classified images were then analyzed to extract 2D grain size measurements from the samples in a high-throughput manner. ML models were developed to predict morphological features based on processing parameters such as solvent ratio, additive type, and additive ratio. GISAXS-based properties were predicted with strong performances ($ R^2$ > 0.75), while AFM-based property predictions were less accurate ($ R^2$ < 0.60), likely due to the localized nature of AFM measurements compared to the bulk information captured by GISAXS. Beyond model performance, interpretability was addressed using Shapley Additive exPlanations (SHAP). SHAP analysis revealed that the additive ratio had the largest impact on morphological predictions, where additive provides the BCP chains with increased volume to rearrange into thermodynamically favorable morphologies. This interpretability helps validate model predictions and offers insight into parameter importance. Altogether, the presented framework combining high-throughput characterization and interpretable ML offers an approach to exploring and optimizing BCP thin film morphology across a broad processing landscape.
Materials Science (cond-mat.mtrl-sci)
Burgers rings as topological signatures of Eshelby-like plastic events in glasses
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-05-30 20:00 EDT
Arabinda Bera, Ido Regev, Alessio Zaccone, Matteo Baggioli
Eshelby-like quadrupolar structures serve as the fundamental microscopic units for characterizing plastic instabilities in amorphous solids and play a crucial role in explaining their mechanical failure, including the formation of shear bands. However, identifying Eshelby-like plastic events in glasses remains challenging due to their inherent structural and dynamical complexity. In this work, we show that Eshelby-like structures can be precisely identified and localized using a topological invariant known as the continuous Burgers vector. By combining analytical and simulation techniques, we reveal the emergence of a topological Burgers ring around Eshelby plastic events, enabling the precise identification of their center of mass and capturing their orientation as well. This proposed method offers a clear and unambiguous framework to locate and characterize the plastic rearrangements that govern plasticity in glasses.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Materials Science (cond-mat.mtrl-sci), Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
v1: comments welcome
Theory of chiral-phonon-activated spin Seebeck effect
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-30 20:00 EDT
Naoki Nishimura, Takumi Funato, Mamoru Matsuo, Takeo Kato
We theoretically explore the generation of spin current driven by a temperature gradient in a junction between a chiral insulator and a normal metal. Based on the gyromagnetic effect caused by microscopic rotation due to phonons, we derive a formula for a spin current when a finite temperature difference is imposed at two ends of the sample. We clarify how the spin current depends on the sample geometry, the thermal conductivity, the heat conductance at the interface, and the average temperature. Our formulation provides a microscopic foundation for the chiral-phonon-activated spin Seebeck effect without relying on magnetism and spin-orbit interactions.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
17 pages, 2 figures
Thermodynamic Constraints in DRAM cells: Experimental Verification of Energy Efficiency Limits in Information Erasure
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-30 20:00 EDT
Takase Shimizu, Kensaku Chida, Gento Yamahata, Katsuhiko Nishiguchi
We measured the energy efficiency of information erasure using silicon DRAM cells capable of counting charges on capacitors at the single-electron level. Our measurements revealed that the efficiency decreased as the erasure error rate decreased, and notably, the Landauer limit was not achieved even under effectively infinite-time operation. By comparing the measured efficiency with the Landauer limit, we identified a thermodynamic constraint that prevents DRAM from reaching this limit: the inability to prepare the initial state in thermal equilibrium, which in turn prohibits quasi-static operations. This finding has broad implications for DRAM cells and for many electronic circuits sharing similar structures. Furthermore, it validates our experimental approach to discovering thermodynamic constraints that impose tighter, practically relevant limits, opening a new research direction in information thermodynamics.
Statistical Mechanics (cond-mat.stat-mech), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
8 pages, 5 figures
Multiple-Nanowire Superconducting Quantum Interference Devices: Critical Currents, Symmetries, and Vorticity Stability Regions
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-30 20:00 EDT
An ordinary superconducting quantum interference device (SQUID) contains two weak links connected in parallel. We model a multiple-wire SQUID (MW-SQUID), generalized in two ways. First, the number of weak links, which are provided by parallel superconducting nanowires, is larger than two. Second, the current-phase relationship of each nanowire is assumed linear, which is typical for a homogeneous superconducting thin wire. For such MW-SQUIDs, our model predicts that the critical current ($ I_c$ ) is a multi-valued function of the magnetic field. We also calculate vorticity stability regions (VSR), i.e., regions in the current-magnetic field plane in which, for a given distribution of vortices, the currents in all wires are below their critical values, so the vortices do not move between the cells. The VSRs have rhombic shapes in the case of two-wire SQUIDS and have more complicated shapes in the case of many nanowires. We present a classification of such VSRs and determine conditions under which VSR is disjoint, leading to 100% supercurrent modulation and quantum phase transitions. According to the model, the maximum critical current curves obey $ IB$ symmetry, while each VSR obeys $ IBV$ symmetry. The model predicts conditions at which MW-SQUID exhibits a perfect diode effect in which the critical current of one polarity is zero while it is not zero for the opposite polarity of the bias current. We also provide a classification of the stability regions produced by (1) completely symmetric, (2) phase disordered, (3) position disordered, (4) critical current disordered, and (5) completely disordered multi-wire SQUIDs.
Superconductivity (cond-mat.supr-con)
24 pages, 20 figures
Integrated phononic waveguide on thin-film lithium niobate on diamond
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-30 20:00 EDT
Sultan Malik, Felix M. Mayor, Wentao Jiang, Hyunseok Oh, Carl Padgett, Viraj Dharod, Jayameenakshi Venkatraman, Ania C. Bleszynski Jayich, Amir H. Safavi-Naeini
We demonstrate wavelength-scale phononic waveguides formed by transfer-printed thin-film lithium niobate (LN) on bulk diamond (LNOD), a material stack that combines the strong piezoelectricity of LN with the high acoustic velocity and color-center compatibility of diamond. We characterize a delay line based on a 100 micron long phononic waveguide at room and cryogenic temperatures. The total insertion loss through the device at 4 kelvin is -5.8 dB, corresponding to a >50% transducer efficiency, at a frequency of 2.8 gigahertz. Our work represents a step towards phonon-mediated hybrid quantum systems consisting of strain-sensitive color centers in diamond.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph)
6 pages, 4 figures
Breakdown of the quantum anomalous Hall effect under microwave drives
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-30 20:00 EDT
Torsten Röper, Daniel Rosenbach, Achim Rosch, Alexey A. Taskin, Yoichi Ando, Erwann Bocquillon
Quantum anomalous Hall (QAH) insulators exhibit chiral dissipationless edge states without an external magnetic field, making them a promising material for quantum metrology and microwave applications. However, the breakdown of the zero-resistance state at low currents hinders progress. We investigate and characterize this breakdown under microwave fields (1-25 GHz) by measuring the increase of longitudinal resistance in RF Hall bars and RF Corbino devices made from V-doped (Bi,Sb)$ _2$ Te$ _3$ films. Our results point to the role of heating of electron-hole puddles under microwave irradiation, thereby fostering hopping transport. Our work offers insights critical for GHz-range QAH applications.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Magnetostrictive Phononic Frequency Combs
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-30 20:00 EDT
Guanqi Ye, Ruitong Sun, Junning Zhao, Fusheng Ma
Magnetostriction, mechanical-to-magnetic or magnetic-to-mechanical response, plays a pivotal role in magneto-mechanical systems. Here, we propose and experimentally demonstrate a magneto-mechanical frequency comb via the three-wave mixing mechanism, which solely requires the involvement of the fundamental mode f0 of a magnetostrictive macroresonator. Two types of combs, i.e., the integer-harmonic combs and the half-integer-harmonic combs, are observed in kHz regime with Hz resolution by magnetically pumping the mm-scale resonator with near-resonant f0. The integer-harmonic combs are centered at lfp, while the half-integer-harmonic combs are centered at (2n - 1) fp/2 resulting from the period-doubling bifurcation of fp. The tooth spacing of both types of combs is determined and can be continuously tuned by changing fs from Hz to kHz. Moreover, the half-integer-harmonic combs can be purposely switched with frequency shifting half a tooth spacing via suppressing period-doubling bifurcation. The experimentally observed formation, evolution, and switching of combs can be well understood by introducing the bias magnetical force and modulated linear stiffness into the Duffing equation. Our findings on magnetically manipulated phononic frequency comb could provide a magneto-mechanical platform for potential non-invasive and contactless sensing and even antenna for wireless operation.
Strongly Correlated Electrons (cond-mat.str-el)
Magnonic chaotic comb
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-30 20:00 EDT
Ruitong Sun, Guanqi Ye, Fusheng Ma
Optical chaotic comb, possessing the key metrics of intrinsic random amplitude, phase, and frequency modulation of comb lines, emerges as a novel chaotic source in information systems for coherence tomography, parallel ranging, and secure communications. Considering the analogies between magnons and photons, the magnonic analog of optical chaotic combs is expected but not yet explored. Here, we propose a scenario of generating magnonic chaotic combs based on mode coupling mechanism in magnonic systems. Especially, we theoretically demonstrate the realization of magnonic frequency combs through three-wave mixing between ultra-strongly coupled magnons in silicon based synthetic antiferromagnet platform. It is found that the realized magnonic frequency combs can transition to chaos via various routes, i.e., subcritical Hopf bifurcation, torus-doubling bifurcation, and torus breakdown. The robustness of magnonic chaotic combs is verified by characterizing the Poincare map, the bifurcation diagrams, and the largest Lyapunov exponents. Furthermore, the unique characters of chaotic combs, perturbation hypersensitivity and noise immunity, are conceptually validated by identifying latent magnetic signal contaminated by inherent noise. Our findings provide a magnonic paradigm of chaotic dynamics in complex systems for potential applications in CMOS-integrated metrology, sensing, and communication.
Strongly Correlated Electrons (cond-mat.str-el)
V. J. Emery and P. W. Anderson’s views and related issues regarding the basics of cuprates: a re-look
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-30 20:00 EDT
In 1991, V. J. Emery in his important review article entitled “Some aspects of the theory of high temperature superconductors”\cite{emery1} argued against the Zhang-Rice reduction of three-band to an effective one-band model. In his words “…therefore it seems that the simple $ t-J$ model does not account for the properties of high temperature superconductors”. Over approximately 35 years after the initial debates\cite{debates} much has happened in the field pertaining to this topic. Even though it is one of the most discussed issue, a comprehensive account and the required resolution are lacking. Connected to the debate over one-band versus three-band models is another discussion: the one-component versus two-component model for cuprates. The two-component model is most strongly advocated by Barzykin and Pines\cite{bp}. In this article the author attempts a perspective and a re-look on some of these issues. After an analysis of a large body of literature, author finds that V. J. Emery’s criticism of the Zhang-Rice reduction was correct. Many central experimental features of cuprates cannot be rationalized within the one-band model, and Johnston-Nakano scaling is one such example. Other examples are also discussed. Author introduces a simple-minded toy model to illustrate the core issues involved.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
12 pages, and 7 figures
Emergent Quasiparticles & Field-Tuned RIXS Spectra in a Trimerized Spin-1/2 Chain
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-30 20:00 EDT
Subhajyoti Pal, Pradeep Thakur, Ashis Kumar Nandy, Anamitra Mukherjee
We investigate spin-flip excitations in the spin-1/2 trimer chain $ \rm{Cu_3(P_2O_6OH)_2}$ , featuring an antiferromagnetic exchange motif $ J_1$ -$ J_1$ -$ J_2$ with $ J_1 < J_2$ . Using density matrix renormalization group (DMRG) simulations, we demonstrate that single-spin-flip processes induced by resonant inelastic X-ray scattering (RIXS) generate emergent gapless modes governed by the underlying trimer periodicity alongside distinct high-energy excitations. By combining exact diagonalization and real-space renormalization group (RG) techniques, we attribute these features to fractionalized spinons and composite quasiparticles arising from one- and two-trimer excitations. Furthermore, we show that multi-spin RIXS excitations yield experimentally distinguishable spectral signatures of composite modes absent in single-spin-flip spectra. At the field-induced 1/3 magnetization plateau, single-spin-flip RIXS spectra evolves with the magnetic field to favor spin-polarized composite quasiparticles. This trend culminates in a gapless spectrum of spin-1 excitations beyond the plateau, paving the way for field-tuned Bose condensation of composite modes.
Strongly Correlated Electrons (cond-mat.str-el)
Polymer-modulated evaporation flow enables scalable self-assembly of highly aligned nanowires
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-30 20:00 EDT
Liyiming Tao, Zechao Jiang, Shiyuan Hu, Lin Du, Qiuting Zhang, Jiajia Zhou, Masao Doi, Xiaojun Wu, Xingkun Man, Ye Xu
Highly aligned nanowire networks are essential for enabling anisotropic optical, electrical, and sensing functionalities in next-generation devices. However, achieving such alignment typically requires complex fabrication methods or high-energy processing. Here, we present a simple and scalable self-assembly strategy that uses a viscosity-enhancing polymer additive to modulate fluid flows during solvent evaporation. The addition of carboxymethylcellulose sodium (CMC-Na) reshapes the evaporation-driven flow field and generates a compressional flow region near the drying edge. Within this region, rotation-inducing velocity gradients progressively align silver nanowires (AgNWs) into highly ordered arrays. This unique mechanism yields uniform AgNW coatings with a high degree of nanowire alignment and tunable areal density across centimeter-scale areas. The resulting films exhibit strong broadband anisotropy, including polarization-dependent transmission in both visible and terahertz (THz) regimes and angle-dependent electrical conductivity. The approach also integrates naturally with dip-coating-based shear alignment, enabling programmable control over alignment direction and spatial patterning. This work establishes a robust, polymer-enabled mechanism for bottom-up nanowire alignment and offers a passive, energy-efficient route for fabricating anisotropic nanostructured coatings.
Soft Condensed Matter (cond-mat.soft)
Optical Controllable Spin-Polarization in Two Dimensional Altermagnets via Robust Spin-Momentum Locking Excitons
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-30 20:00 EDT
Jiuyu Sun, Jinzhe Han, Yongping Du, Erjun Kan
Spin-momentum locking (SML) excitons in two-dimensional semiconductors are appealing to programmable optical control of spin-polarized carriers in ultrafast spintronics. To address the current thirsty for long-lived excitons with zero-external-field stability and room-temperature spin-polarization, we hereby predict the existence of intrinsically SML excitons in altermagnetic V$ _2 X_2$ O ($ X=$ S, Se) driven by giant non-relativistic spin-splittings ($ >$ 1.2 eV). First-principles calculations reveal SML excitons with binding energies exceeding 1400 meV in monolayers and 430 meV in their van der Waals heterobilayers, along with stacking-dependent optical selection rules for tunable interlayer excitons. These remarkable physical properties, combined with their long radiative lifetimes, strongly suggest the feasibility of SML excitons with robust spin-polarization at room temperature. Our work provides a new paradigm for SML exciton physics via the novel altermagnetism, opening up new possibilities for all-optical manipulation in advanced opto-spintronics.
Materials Science (cond-mat.mtrl-sci)
Hierarchy of localized many-body bound states in an interacting open lattice
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-05-30 20:00 EDT
We unveil the mechanism for the formation of puzzled boundary-localized bound states in a spinless fermionic open lattice with nearest-neighbor interactions. By solving the Bethe-ansatz equation analytically, we uncover asymmetrical string solutions corresponding to the boundary-localized bound states, which emerge in systems with at least three particles. The localized bound states can become bound states in continuum in a suitable parameter region. When the number of particles increases to five or more, additional bound states away from the edge are also observed. Through rigorous analysis, we derive recurrence relations of the quasi-momentum of the localized states as a function of the number of particles, predicting the presence of hierarchy of localized many-body bound states in interacting open lattices.
Quantum Gases (cond-mat.quant-gas)
6 pages, 3 figures
Unconventional Hall Effect in Gapless Superconductors: Transverse Supercurrent Converted from Normal Current
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-30 20:00 EDT
Miaomiao Wei, Longjun Xiang, Fuming Xu, Bin Wang, Jian Wang
A normal metallic system proximitized by a superconductor can exhibit a gapless superconducting state characterized by segmented Fermi surfaces, as confirmed experimentally. In such a state, quasiparticle states remain gapless along one direction, while a superconducting gap opens in the perpendicular direction. This anisotropy enables a novel Hall effect in gapless superconductors, termed the superconducting Hall effect (ScHE), where a longitudinal normal current carried by quasiparticles is converted into a dissipationless transverse supercurrent. Employing both the thermodynamic approach for bulk systems and quantum transport theory for a four-probe setup, we demonstrate the existence of this effect and reveal its intrinsic origin as the quasiparticle Berry curvature. The predicted ScHE can be experimentally verified via the standard angular-dependent Hall measurements performed on gapless superconductors.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
6 pages, 3 figures
Tuning the Chern number of Kitaev quantum spin liquid
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-30 20:00 EDT
Seong Jun Kwon, Kyusung Hwang, Suk Bum Chung
It is now well understood that non-Kitaev spin interactions can be added to the Kitaev quantum spin liquid by applying external fields. Recent years have seen intensive discussion on the possible phase transitions that these spin interactions induce. In this paper, we will show through the perturbation theory the possibility of accessing a gapped spin liquid phase with a higher Chern number through, in contrast to the cases studied in literature, a continuous phase transition. Such a transition may be induced by external tuning parameters such as electric field and hydrostatic pressure.
Strongly Correlated Electrons (cond-mat.str-el)
22 pages, 12 figures
Higher-order thermal transport theory for phonon thermal transport in semiconductors using lattice dynamics calculations and the Boltzmann transport equation
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-30 20:00 EDT
Ankit Jain, Yagyank Srivastava, Amey G. Gokhale, Nidheesh Virakante, Hardik L. Kagdada
The phonon thermal conductivity of semiconducting periodic solids can be obtained using the lattice dynamics calculations along with the Boltzmann transport equation and with input from density functional theory calculations. These calculations have resulted in an excellent agreement with experiments without requiring any fitting parameters. However, over the last decade, many material systems have been identified where the lowest level lattice dynamics theory, which is based on the relaxation time approximation solution of the Boltzmann transport equation and considers potential energy surface sampling around the static equilibrium positions of atoms with only three-phonon scatterings, is proved insufficient in describing the thermal transport physics. In this article, we review these higher-order developments in the lattice dynamics theory to describe thermal transport in periodic semiconducting solids. We start with a brief discussion of the lowest-order theory and discuss its limitations along with proposed developments to address these limitations. We discuss prominent success cases of these higher-order developments and present our recommendations on their use for various material systems. Considering that many of these higher-order developments are computationally more demanding compared to the lowest-order theory, we also discussed data-driven approaches to accelerate these calculations. This review article is intended to serve as a reference for both novice and experienced researchers in this field.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Dynamic signature of the thermodynamic transition in a novel mean field system
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-30 20:00 EDT
Ehtesham Anwar, Ujjwal Kumar Nandi, Palak Patel, Sanket Kumawat, Sarika Maitra Bhattacharyya
Understanding the connection between thermodynamics and dynamics in glass-forming liquids remains a central challenge in condensed matter physics. In this study, we investigate a novel model system that enables a continuous crossover from a standard three dimensional liquid to a fully connected mean field like system by introducing pseudo neighbours. These pseudo neighbours enhance the effective connectivity of the system without altering its local structure. While their presence slows down the dynamics, they influence thermodynamic properties even more significantly. In particular, the configurational entropy obtained via thermodynamic integration vanishes at a temperature much higher than the temperature where the dynamics begin to slow down, leading to a clear breakdown of the Adam Gibbs relation. To uncover a possible dynamical signature of this thermodynamic transition, we analyse bond breakage dynamics. Unlike real-real bonds, which decay similarly in both the parent Kob Andersen model and its mean field variant, real-pseudo bonds exhibit long lived, persistent behaviour with strong temperature dependence. These bonds do not fully decay over time, leading to a finite saturation value of the bond breakage correlation function. Remarkably, we show that the number of surviving pseudo bonds can be analytically estimated and correlates directly with the thermodynamic transition temperature T_K. We propose a phenomenological relation between T_K and the number of surviving pseudo-bonds, establishing a novel link between thermodynamic and dynamic observables. Our results suggest that these persistent pseudo bonds serve as a robust dynamical signature of the thermodynamic transition, and the system might have properties analogous to those of randomly bonded ultrastable glasses.
Soft Condensed Matter (cond-mat.soft), Disordered Systems and Neural Networks (cond-mat.dis-nn), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Statistical Mechanics (cond-mat.stat-mech)
15 pages, 24 figures
Parton Mean-Field Theory of a Rydberg Quantum Spin Liquid induced by Density-Dependent Peierls Phases
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-05-30 20:00 EDT
Benno Bock, Simon Ohler, Michael Fleischhauer
We derive a parton mean-field Hamiltonian for Rydberg excitations on a honeycomb lattice with nearest and density-dependent, complex next-nearest neighbor hopping. Numerical results obtained from exact diagonalization of small systems have given indications for a ground state that is a chiral spin liquid (CSL) [this http URL. 5, 013157 (2023)]. Here we provide further evidence for this. Calculating the ground-state wavefunction self-consistently, we show that the mean-field Hamiltonian fulfills the requirements for a CSL ground state, resulting from a projected symmetry group classification and verify the expected twofold topological degeneracy on a torus. Furthermore we find very good overlap with the ground-state wavefunctions obtained by exact diagonalization of the original Hamiltonian.
Quantum Gases (cond-mat.quant-gas)
7 pages, 7 figures
Two-gap superconductor ZrB12 with dynamic stripes and charge density waves: Crystal structure, physical properties and pairing mechanism
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-30 20:00 EDT
A. N. Azarevicha, N. B. Bolotinab, O. N. Khrykinab, A. V. Bogacha, K. M. Krasikova, A. Yu. Tsvetkovc, S. Yu. Gavrilkinc, V. V. Voronova, S. Gabanid, K. Flachbartd, A. N. Azarevich, N. B. Bolotina, O. N. Khrykina, A. V. Bogach, K. M. Krasikov, A. Yu. Tsvetkov, S. Yu. Gavrilkin, V. V. Voronov, S. Gabani, K. Flachbart, A. V. Kuznetsov, N. E. Sluchanko
A review of long-term studies of ZrB12 and LuB12 superconductors with very similar conduction bands and phonon spectra, but with radically different (by a factor of 15-20) critical temperatures and magnetic fields is presented. A detailed analysis of well-known studies in combination with new results of structural, thermodynamic and charge transport measurements obtained here for these metallic dodecaborides with Jahn-Teller instability of the rigid boron network and with dynamic charge stripes allows us to conclude in favor of the primary role of nanoscale effects of electron phase separation, leading to the formation of one-dimensional dynamic chains with different configurations of fluctuating charges, which in the case of ZrB12 are predominantly 2p-states, and for LuB12- 5d-2p states. We propose a new plasmon-phonon pairing mechanism in ZrB12, which may be common to different classes of high-Tc superconductors.
Superconductivity (cond-mat.supr-con)
27 pages, 18 figures
Importance of pressure-dependent electronic interactions and magnetic order on pressure-driven insulator-metal transitions in MnO and NiO
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-30 20:00 EDT
Bei-Lei Liu, Yue-Chao Wang, Yuan-Ji Xu, Xingyu Gao, Hai-Feng Liu, Hai-Feng Song
The pressure-driven insulator-metal transition is a crucial topic in condensed matter physics. However, even for the prototypical strongly correlated system, NiO, the critical pressure for transition remains debated. In this work, we evaluated the electronic interactions over a wide range of pressures based on our developed doubly-screened Coulomb correction method and investigated the effects of pressure-dependent electronic interactions and their interplay with magnetic order on the transition. As a validation of the method, we also performed calculations on MnO. The results show that the hybrid functional combined with pressure-dependent screening parameters reasonably describes the insulator-metal transition in MnO. The insulating band gap of antiferromagnetic (AFM) NiO also match well with experiments in both trend and value, which is better than the method using fixed parameters. Further calculations considering magnetic order indicate that as the electronic interactions weaken under pressure, the AFM state of NiO will no longer be stable, a phenomenon that was not observed in previous works. In addition, the results show that, compared with DFT+$ U$ within the on-site Coulomb correction framework, the hybrid functional provides a more accurate description of the properties of MnO and NiO at high pressures, highlighting the key role of non-local effects. Our work provides a possible explanation for the long-standing discrepancies in NiO and offers guidance for the development of first-principles methods for correlated electron systems under pressure.
Strongly Correlated Electrons (cond-mat.str-el)
10 pages, 9 figures
Spin and Charge Control of Topological End States in Chiral Graphene Nanoribbons on a 2D Ferromagnet
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-30 20:00 EDT
Leonard Edens, Francisco Romero Lara, Trisha Sai, Kalyan Biswas, Manuel Vilas-Varela, Fabian Schulz, Diego Peña, Jose Ignacio Pascual
Tailor-made graphene nanostructures can exhibit symmetry-protected topological boundary states that host localized spin-$ 1/2$ moments. However, one frequently observes charge transfer on coinage metal substrates, which results in spinless closed-shell configurations. Using low temperature scanning tunneling spectroscopy, we demonstrate here that pristine topologically nontrivial chiral graphene nanoribbons synthesized directly on the ferromagnet $ \textrm{GdAu}_2$ can either maintain a charge-neutral diradical singlet or triplet configuration, or exist in a singly anionic doublet state. As an underlying mechanism, we identify a moiré-modulated work function and exchange field, as corroborated by Kelvin-probe force microscopy and spin-flip spectroscopy. The joint electrostatic and magnetic interactions allow reversibly switching between the three spin multiplicities by atomic manipulation. We introduce an effective Hubbard dimer model that unifies the effects of local electrostatic gating, electron-electron-correlation, hybridization and exchange field to outline the phase diagram of accessible spin states. Our results establish a platform for the local control of $ \pi$ -radicals adsorbed on metallic substrates.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
7 pages, 4 figures
Unconventional magnon transport in antiferromagnet NiPS$_3$ induced by an anisotropic spin-flop transition
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-30 20:00 EDT
Peisen Yuan, Beatriz Martín-García, Evgeny Modin, M. Xochitl Aguilar-Pujol, Fèlix Casanova, Luis E. Hueso
Nonlocal magnon transport can provide valuable insight into the magnetic properties of magnetic insulators (MIs). A spin-flop transition, a typical magnetic reorientation in antiferromagnets, is expected to affect mag non transport, but studies on this topic are still rare and remain challenging, especially for van der Waals materials. Here we demonstrate the unconventional magnon transport driven by an anisotropic spin-flop transition in the van der Waals antiferromagnet NiPS$ _3$ . Examining the nonlocal voltage from thermally driven magnons reveals sharp jumps at certain directions when an inplane magnetic field aligns with the b-axis of NiPS$ _3$ , attributed to an in-plane anisotropic spin-flop transition. Furthermore, thermally driven magnon signal exhibits a 1/d$ ^2$ decay in thin NiPS$ _3$ , evidencing that it is dominated by the intrinsic spin Seebeck effect. Our findings highlight that the electrical detection of magnon currents in a nonlocal device geometry serves as a powerful approach for studying magnetic phase transitions in MIs.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
16 pages, 5 figures, and Supporting Information
Nano Letters 25, 5350-5357 (2025)
Comment on “Long-range crossed Andreev reflection in a topological insulator nanowire proximitized by a superconductor” by Junya Feng et al
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-30 20:00 EDT
We argue that the interpretation of the experiment [Nature Physics 21, 708-715 (2025)] is misleading in two respects. First, the bias voltages impact the non-local differential conductance randomly, rather than systematically, and the bias symmetry of the non-local conductance in Fig. 3 can be explained by a fine tuned self-gating effect. Second, the full knowledge of the conductance matrix is insufficient to conclude on the relative values of the crossed-Andreev and elastic cotunneling probabilities, in particular on the dominance of one of them.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
Comment on arXiv:2407.02383 published in Nature Physics 21, 708-715 (2025)
Dominant Kitaev interaction and field-induced quantum phase transitions in triangular-lattice KCeSe2
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-30 20:00 EDT
Mingtai Xie, Zheng Zhang, Weizhen Zhuo, Wei Xu, Jinfeng Zhu, Jan Embs, Lei Wang, Zikang Li, Huanpeng Bu, Anmin Zhang, Feng Jin, Jianting Ji, Zhongwen Ouyang, Liusuo Wu, Jie Ma, Qingming Zhang
Realizing Kitaev interactions on triangular lattices offers a compelling platform for exploring quantum-spin-liquid physics beyond the conventional honeycomb lattice framework. Here, we investigate the triangular-lattice antiferromagnet KCeSe2, where multiple probes reveal strong magnetic anisotropy suggesting significant Kitaev physics. Through detailed and combined analysis of magnetization, neutron scattering, and thermodynamic experiments, we identify dominant ferromagnetic Kitaev ($ K = -1.82$ K) and antiferromagnetic Heisenberg ($ J = 1.34$ K) interactions that stabilize a stripe-$ yz$ ordered ground state via an order-by-disorder mechanism. Magnetic fields applied along the Kitaev bond direction induce two phase transitions at 1.67 T and 3.8 T, consistent with density matrix renormalization group (DMRG) calculations predictions of a progression from stripe-$ yz$ to stripe-canted and spin-polarized phases. Near the 1.67 T quantum critical point, enhanced quantum fluctuations suggest conditions favorable for exotic excitations. These results establish KCeSe2 as a platform for exploring Kitaev physics on triangular lattices.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
8 Pages, 4 Figures
Phys. Rev. Research 7, 023198 (2025)
Sequential tilting 4D-STEM for improved momentum-resolved STEM field mapping
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-30 20:00 EDT
Christoph Flathmann, Ulrich Ross, Jürgen Belz, Andreas Beyer, Kerstin Volz, Michael Seibt, Tobias Meyer
Momentum-resolved scanning transmission electron microscopy (MRSTEM) is a powerful phase-contrast technique that can map lateral magnetic and electric fields ranging from the micrometer to the subatomic scale. Resolving fields ranging from a few nanometers to a few hundred nanometers, as well as across material junctions, is particularly important since these fields often determine the functional properties of devices. However, it is also challenging since they are orders of magnitude smaller than atomic electric fields. Thus, subtle changes in diffraction conditions lead to significant changes in the measured MRSTEM signal. One established approach to partially overcome this problem is precession electron diffraction, in which the incident electron beam is continuously precessed while precession-averaged diffraction patterns are acquired. Here, we present an alternative approach in which we sequentially tilt the incident electron beam and record a full diffraction pattern for each tilt and spatial position. This approach requires no hardware modification of the instrument and enables the use of arbitrary beam tilt patterns that can be optimized for specific applications. Furthermore, recording diffraction patterns for every beam tilt allows access to additional information. In this work, we use this information to create virtual large-angle convergent beam electron diffraction (vLACBED) patterns to assess MRSTEM data quality and improve field measurements by applying different data analysis methods beyond simple averaging. The presented data acquisition concept can readily be applied to other 4D-STEM applications.
Materials Science (cond-mat.mtrl-sci)
X-ray diffraction from smectic multilayers: crossover from kinematical to dynamical regime
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-30 20:00 EDT
V. V. Samsonov, K. V. Nikolaev, B. I. Ostrovskii, S. N. Yakunin
We study X-ray diffraction in smectic liquid crystal multilayers. Such systems are fabricated as freely suspended films and have a unique layered structure. As such, they can be described as organic Bragg mirrors with sub-nanometer roughness. However, an interesting peculiarity arises in the diffraction on these structures: the characteristic shape of diffraction peaks associated with dynamical scattering effects is not observed. Instead, the diffraction can be well described kinematically, which is atypical for Bragg mirrors. In this article we investigate the transition between the kinematical and dynamical regimes of diffraction. For this purpose, we analyze the reflection of synchrotron radiation on a real liquid crystal sample with both kinematical and dynamical theories. Furthermore, based on these theories, we derive a quantitative criterion for the transition from the kinematical to the dynamical regime. This, in turn, allows us to explain the peculiar diffraction behavior in smectic films with thicknesses exceeding thousands of molecular layers.
Soft Condensed Matter (cond-mat.soft)
This is an original manuscript of 14 pages with 6 figures. It is intended for submission to the “Journal of Applied Crystallography”
Unconventional Temperature Dependence of Exciton Diamagnetism in 2D Ruddlesden-Popper Lead Halide Perovskites
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-30 20:00 EDT
William A. Smith, Fumiya Katsutani, Jin Hou, Hao Zhang, Jean-Christophe Blancon, Hiroyuki Nojiri, Aditya D. Mohite, Andrey Baydin, Junichiro Kono, Hanyu Zhu
Layered hybrid perovskites containing larger organic cations have demonstrated superior environmental stability, but the presence of these insulating spacers also strengthens the exciton binding energy, which contributes to reduced carrier separation. The consequences of increased binding energy on device efficiency are still not fully documented, and binding energy measurements are often conducted at cryogenic temperatures where linewidths are decreased and a series of hydrogen-like bound states can be identified, but not under ambient conditions where devices are expected to operate. In contrast to the quenching observed in 3D perovskites such as methylammonium lead iodide, where exciton binding energies are thought to decrease at higher temperatures, we present evidence for a smaller excitonic radius at higher temperatures in the $ n=5$ member of butylammonium-spaced methylammonium lead iodide, (BA)$ _2$ (MA)$ _{n-1}$ Pb$ _n$ I$ _{3n+1}$ . We measured the temperature-dependent diamagnetic shift coefficient in magnetic fields up to 40,T, which is one-third as large at room temperature as those at cryogenic temperatures. In both the ideal 2D and 3D hydrogen models, this trend would indicate that the exciton binding energy more than triples at room temperature.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Si(100)-SiO$_2$ Trap Density Dependence on Sample Processing
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-30 20:00 EDT
Adam J. Czarnecki, Nikola L. Kolev, Patrick See, Nick Sullivan, Wyatt A. Behn, Neil J. Curson, Taylor J.Z. Stock, Peter Grütter
As silicon-based devices continue to shrink to the nanoscale, traps at the Si-SiO$ _2$ interface pose increasing challenges to device performance. These traps reduce channel carrier mobility and shift threshold voltages in integrated circuits, and introduce charge noise in quantum systems, reducing their coherence times. Knowledge of the precise location of such traps aids in understanding their influence on device performance. In this work, we demonstrate that frequency-modulated atomic force microscopy (fm-AFM) allows the detection of individual traps. We use this to study how sample preparation, specifically the introduction of a buried hydrogen termination layer, and post-processing annealing in forming gas (N$ _2$ +H$ _2$ ), affects the density of donor-like traps in Si(100)-SiO$ _2$ systems. We spatially map and quantify traps in both conventionally prepared (“pristine”) silicon samples and those processed under ultra-high vacuum for hydrogen resist lithography (HRL). We confirm previous studies demonstrating hydrogen passivation of traps and find that hydrogen termination further reduces the donor-like trap density. We also observe a significant reduction in two-level donor-like traps in the hydrogen-terminated samples compared to pristine silicon samples. These findings suggest that HRL-prepared silicon may offer advantages for high-performance nanoscale and atomic-scale devices due to reduced trap densities.
Materials Science (cond-mat.mtrl-sci)
Eigenstate Thermalization Hypothesis (ETH) for off-diagonal matrix elements in integrable spin chains
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-30 20:00 EDT
Federico Rottoli, Vincenzo Alba
We investigate off-diagonal matrix elements of local operators in integrable spin chains, focusing on the isotropic spin-$ 1/2$ Heisenberg chain ($ XXX$ chain). We employ state-of-the-art Algebraic Bethe Ansatz results, which allow us to efficiently compute matrix elements of operators with support up to two sites between generic energy eigenstates. We consider both matrix elements between eigenstates that are in the same thermodynamic macrostate, as well as eigenstates that belong to different macrostates. In the former case, focusing on thermal states we numerically show that matrix elements are compatible with the exponential decay as $ \exp(-L |{M}^{\scriptscriptstyle{\mathcal{O}}}{ij}|)$ . The probability distribution functions of $ {M}{ij}^{\scriptscriptstyle{\mathcal{O}}}$ depend on the observable and on the macrostate, and are well described by Gumbel distributions. On the other hand, matrix elements between eigenstates in different macrostates decay faster as $ \exp(-|{M’}{ij}^{\scriptscriptstyle{\mathcal{O}}}|L^2)$ , with $ {M’}{ij}^{\scriptscriptstyle \mathcal{O}}$ , again, compatible with a Gumbel distribution.
Statistical Mechanics (cond-mat.stat-mech), Quantum Gases (cond-mat.quant-gas), Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Theory (hep-th), Quantum Physics (quant-ph)
18 pages, 7 figures, 1 appendix
Localized surface plasmons in a Weyl semimetal nanosphere
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-30 20:00 EDT
Francesco M. D. Pellegrino, Francesco Buccheri, G. G. N. Angilella
In this study, we investigate the localized surface plasmon modes of a sub-wavelength spherical nanoparticle composed of a Weyl semimetal, taking into account the axion modification of electrodynamics. We derive analytical solutions for dipole and quadrupole normal modes by employing the quasistatic approximation. The axion term leads to modified Fröhlich conditions, resulting in multiple non-degenerate plasmonic resonances with distinct polarization dependencies. In contrast to isotropic conventional metals, the magnetoelectric properties of Weyl semimetals enable an incident electromagnetic field, with the electric field transverse to the surface of the sphere, to excite a localized surface plasmon.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph), Optics (physics.optics)
13 pages, 2 figures
Measuring topological invariants of even-dimensional non-Hermitian systems through quench dynamics
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-05-30 20:00 EDT
The accurate determination of non-Hermitian (NH) topological invariants plays a central role in the study of NH topological phases. In this work, we propose a general framework for directly measuring NH topological invariants in even-dimensional systems through quench dynamics. Our approach hinges on constructing an auxiliary Hermitian matrix topologically equivalent to the original NH Hamiltonian, enabling topological characterization via reduced-dimensional momentum subspaces called band inversion surfaces (BISs). A key insight lies in the emergence of chiral symmetry in the NH Hamiltonian specifically on BISs – a critical property that allows extension of the dynamical characterization scheme previously developed for odd-dimensional NH systems with chiral or sublattice symmetry [Lin et al., Phys. Rev. Res. 7, L012060 (2025)]. We show that NH topological invariants can be extracted from the winding patterns of a dynamical field constructed from post-quench spin textures on BISs. We demonstrate our approach through a detailed analysis of NH Chern insulators and then extend the framework to higher even-dimensional systems by introducing second-order BISs for characterization. This work establishes an experimentally accessible protocol for detecting NH topological invariants in quantum platforms.
Quantum Gases (cond-mat.quant-gas), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
10 pages, 4 figures; complementary to arXiv: 2410.13241
Higher-order Tuning of Interface Physics in Multiphase Lattice Boltzmann
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-30 20:00 EDT
Matteo Lulli, Emily S. C. Ching
Tuning the interface properties of multiphase models is of paramount importance to the final goal of achieving a one-to-one matching with nucleation and cavitation experiments. The surface tension, at the leading order, and the Tolman length, at higher order, play a crucial role in the estimation of the free-energy barrier determining the experimentally observed nucleation rates. The lattice Boltzmann method allows for a computationally efficient modelling approach of multiphase flows, however, tuning results are concerned with the surface tension and neglect the Tolman length. We present a novel perspective that leverages all the degrees of freedom hidden in the forcing stencil of the Shan-Chen multiphase model. By means of the lattice pressure tensor we determine and tune the coefficients of higher-order derivative terms related to surface tension and Tolman length at constant interface width and density ratio. We test the method by means of both hydrostatic and dynamic simulations and demonstrate the dependence of homogeneous nucleation rates on the value of the Tolman length. This work provides a new tool that can be integrated with previously existing strategies thus marking a step forwards to a high-fidelity modelling of phase-changing fluid dynamics.
Statistical Mechanics (cond-mat.stat-mech), Cellular Automata and Lattice Gases (nlin.CG), Fluid Dynamics (physics.flu-dyn)
27 pages, 10 figures
Shot noise from which-path detection in a chiral Majorana interferometer
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-30 20:00 EDT
We calculate the full counting statistics of charge transfer in a chiral Majorana interferometer - a setup where a Dirac mode (an electron-hole mode) is split into two Majorana modes that encircle a number of h/2e vortices in a topological superconductor. Without any coupling to the environment it is known that the low-energy charge transfer is deterministic: An electron is transferred either as an electron or as a hole, dependent on the parity of the vortex number. We show that a stochastic contribution appears if which-path information leaks into the environment, producing the shot noise of random 2e charge transfers with binomial statistics. The Fano factor (dimensionless ratio of shot noise power and conductance) increases without bound as the which-path detection probability tends to unity.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
5 pages, 3 figures
Diffusive noise controls early stages of genetic demixing
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-30 20:00 EDT
Rashmiranjan Bhutia, Stephy Jose, Prasad Perlekar, Kabir Ramola
Theoretical descriptions of the stepping-stone model, a cornerstone of spatial population genetics, have long overlooked diffusive noise arising from migration dynamics. We derive an exact fluctuating hydrodynamic description of this model from microscopic rules, which we then use to demonstrate that diffusive noise significantly alters early-time genetic demixing, which we characterize through heterozygosity, a key measure of diversity. Combining macroscopic fluctuation theory and microscopic simulations, we demonstrate that the scaling of density fluctuations in a spatial domain displays an early-time behaviour dominated by diffusive noise. Our exact results underscore the need for additional terms in existing continuum theories and highlight the necessity of including diffusive noise in models of spatially structured populations.
Statistical Mechanics (cond-mat.stat-mech), Soft Condensed Matter (cond-mat.soft)
6 pages, 3 figures, +Supplemental Material
Dyn-HTE: High-temperature expansion of the dynamic Matsubara spin correlator
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-30 20:00 EDT
Ruben Burkard, Benedikt Schneider, Björn Sbierski
The high-temperature series expansion for quantum spin models is a well-established tool to compute thermodynamic quantities and equal-time spin correlations, in particular for frustrated interactions. We extend the scope of this expansion to the dynamic Matsubara spin-spin correlator and develop a fully analytic algorithm to compute its expansion coefficients. We focus on Heisenberg models with a single coupling constant J and spin lengths S=1/2,1. The expansion coefficients up to 12th order in J/T are precomputed on all possible ~10^6 graphs embeddable in arbitrary lattices and are provided under this https URL. This enables calculation of static momentum-resolved susceptibilities for arbitrary site-pairs or wavevectors. We test our results for the S=1/2 Heisenberg chain and on the triangular lattice model. Moreover, the analytic frequency dependence in the expansion allows for stable analytic continuation to the real-frequency dynamic structure factor. This important application is discussed in a companion letter.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
Code: this https URL Companion letter: arXiv:2505.14571
Group Convolutional Neural Network Ground State of the Quantum Dimer Model
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-05-30 20:00 EDT
Ojasvi Sharma, Sandipan Manna, Prashant Shekhar Rao, G J Sreejith
We estimate the ground state of the square lattice Quantum Dimer Model in a $ \rm{p4m}$ -symmetric Group Convolutional Neural Network (GCNN) representation and show that results in agreement with exact diagonalization (ED) and quantum Monte Carlo (QMC) can be obtained with a $ \mathcal{L}=2$ layer network. In systems of linear size $ L=8$ with Hilbert space dimension $ 3.1\times 10^8$ , GCNN shows fidelity as high as $ 0.99999$ with ED. For $ 12\leq L\leq 32$ , we find excellent agreement with QMC estimates of energy, order parameters and correlation functions. The network is optimized by minimizing the energy estimated from a Metropolis algorithm assisted by a directed loop sampler. We analyze the quantum geometric tensor at the minima for $ \mathcal{L}=1,2$ and $ 3$ and show that the empirical quantum dimension saturates with increasing network complexity due to Metropolis sampling constraints.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech), Strongly Correlated Electrons (cond-mat.str-el)
Fermion parity and quantum capacitance oscillation with partially separated Majorana and quasi-Majorana modes
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-30 20:00 EDT
Tudor D. Stanescu, Sumanta Tewari
In a recent experiment, flux dependent oscillations of the quantum capacitance were observed in a one dimensional spin-orbit coupled semiconductor superconductor heterostructure connected end to end via a quantum dot and threaded by a magnetic flux. In the topological superconducting phase of the heterostructure, the oscillations corresponding to different fermion parity sectors are shifted by half a period and can serve as a mechanism for fermion parity readout or fusion operations involving a pair of localized, well separated Majorana modes. In this work, we demonstrate that flux induced fermion parity dependent oscillations of the quantum capacitance in a disordered semiconductor superconductor quantum dot system can originate not only from topologically protected, spatially well separated Majorana zero modes (MZMs) localized at the wire ends, but also, generically, from partially separated Majorana modes with significant overlap, as well as from quasi-Majorana modes in the topologically trivial phase, which can be viewed as Andreev bound states whose constituent Majorana wave functions are slightly shifted relative to each other and have nonzero amplitude at opposite ends of the wire. Therefore, while the detection of flux dependent oscillations of quantum capacitance marks an important experimental advance, such observations alone do not constitute evidence of the presence of topological Majorana zero modes.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
10 pages, 8 figures