CMP Journal 2026-04-27
Statistics
Nature: 1
Nature Materials: 1
Nature Nanotechnology: 2
Nature Reviews Materials: 1
arXiv: 50
Nature
Telomere-to-Telomere Assembly Using HERRO-Corrected Simplex Nanopore Reads
Original Paper | Genome assembly algorithms | 2026-04-26 20:00 EDT
Dominik Stanojević, Dehui Lin, Sergey Nurk, Paola Florez de Sessions, Mile Šikić
Telomere-to-telomere (T2T) phased assemblies are emerging as a benchmark for reference-quality genomes1,17, though they remain technically and financially demanding, particularly at scale. Generating such assemblies for diploid and polyploid genomes typically involves combining high-accuracy long reads, such as PacBio HiFi16 or the now-deprecated ONT Duplex2 reads, with ultra-long ONT Simplex reads. Using multiple platforms or methods increases the cost and the required amount of genomic DNA. Here, we show that comparable results are possible using error correction of ultra-long ONT Simplex reads and then assembling them using state-of-the-art de novo assembly methods. To achieve this, we have developed the deep learning-based HERRO (Haplotype-aware ERRor cOrrection) framework, which corrects ONT Simplex reads while carefully preserving differences in related genomic sequences. Taking into account informative positions that differentiate the haplotypes or genomic repeat copies, HERRO achieves an increase of read accuracy of up to 100-fold for diploid human genomes. By combining HERRO with the Verkko17 assembler, we reconstruct up to 32 chromosomes telomere-to-telomere, including chromosomes X and Y, and consistently achieve NGA50 values of 100 Mb or higher across several human genomes. HERRO supports both R9.4.1 and R10.4.1 ONT Simplex reads and generalizes well to other species. These results show that error-corrected ONT reads can lower sequencing costs and improve the quality of genomic analyses.
Genome assembly algorithms, Genome informatics, Genomics, Machine learning, Software
Nature Materials
Optical nanoscopy of spatiotemporal metal stripping cooperativity at single-ion and subparticle resolution
Original Paper | Batteries | 2026-04-26 20:00 EDT
Weidong Zhang, Yilu Song, Jie Zhao, Paulo C. D. Mendes, Jorge Ontaneda, Lei Fan, Xiaozhi Xu, Liguang Wang, Yingying Lu, Ctirad Červinka, Kai S. Exner, Sergey M. Kozlov, Ju Li, Xianwen Mao
Coupled ion-electron interfacial reactivities on electroactive particles are complex and crucial to various battery chemistries and dynamics, yet direct visualization of these reactions remains elusive despite advances in operando imaging. Here we report ion-localization optical nanoscopy (ION) with single-ion, subparticle resolution that distinguishes microscopic static and dynamic disorder in ion-generation interfacial reactivity, offering nondestructive, real-time, non-equilibrium insights. We uncover diverse stripping dynamics of zinc anodes, revealing unexpected subparticle-level heterogeneity and challenging conventional views of uniform stripping on (002)-textured zinc. Mesoscale functional descriptors–intraparticle diffusive and electronic coupling strengths–that govern overall stripping uniformity are identified by ION, supported by computational methods and validated by in situ single-particle manipulation. Imaging-derived insights are further translated into ensemble-level strategies enabling exceptional anode reversibility. ION is cost-effective, high-throughput and broadly applicable to myriad ion-participated interfacial processes, including cathode (de)intercalation, solid-electrolyte interphase evolution, ion exchange and catalyst restructuring.
Batteries, Imaging techniques, Single-molecule fluorescence
Nature Nanotechnology
Chemical hardness engineering synchronizes crystallization in perovskite tandems
Original Paper | Devices for energy harvesting | 2026-04-26 20:00 EDT
Ruijia Tian, Kexuan Sun, Yuanyuan Meng, Jiahan Xie, Yaohua Wang, Xiaoyi Lu, Jingnan Wang, Shujing Zhou, Ming Yang, Haibin Pan, Yang Bai, Zhenhua Song, Yingguo Yang, Quan Liu, Bin Han, Bencan Tang, Darren A. Walsh, Hainam Do, Chang Liu, Ziyi Ge
All-perovskite tandem solar cells are constrained by asynchronous crystallization in multicomponent perovskites, which produces vertical compositional gradients, structural inhomogeneity and excessive non-radiative recombination. These effects arise from mismatched coordination and crystallization kinetics among mixed halides and Pb2+/Sn2+ cations. Here we establish a generalizable additive design strategy guided by hard-soft acid-base principles to synchronize nucleation and crystal growth in both wide- and narrow-bandgap perovskites. Borderline-base difluoro(oxalato)borate and hard-base tetrafluoroborate selectively coordinate wide- and narrow-bandgap perovskite precursors, respectively, balancing the crystallization kinetics of PbI2/PbBr2 and PbI2/SnI2 and producing vertically uniform perovskite films with reduced defect densities and suppressed ion migration. In situ optical and structural characterization reveals homogeneous nucleation and direct crystal growth without intermediate halide redistribution. Monolithic two-terminal tandems achieve an efficiency of 30.3% (certified, 30.3%) with improved open-circuit voltage (2.16 V) and fill factor (85.2%), retaining 92% efficiency after 1,000 h of maximum power point tracking. Flexible tandems reach an efficiency of 28.2% (certified, 28.0%). These results establish chemical hardness matching as a universal principle for controlling crystallization in different perovskite systems.
Devices for energy harvesting, Solar cells
A quantum-coherent photon-emitter interface in the original telecom band
Original Paper | Nanophotonics and plasmonics | 2026-04-26 20:00 EDT
Marcus Albrechtsen, Severin Krüger, Juan C. Loredo, Lucio Stefan, Zhe Liu, Yu Meng, Lukas L. Niekamp, Bianca F. Seyschab, Nikolai Spitzer, Richard J. Warburton, Peter Lodahl, Arne Ludwig, Leonardo Midolo
Quantum dots have set benchmarks that far surpass other quantum emitters owing to their ability to deliver high-quality, high-rate and pure photons. However, achieving these exceptional capabilities at telecom wavelengths, bridging the gap to fibre-optic infrastructure and scalable silicon photonics, remains a challenge. Overcoming this difficulty demands high-quality quantum materials and devices that, despite extensive efforts, have not yet been realized. Here we demonstrate waveguide-integrated InAs quantum dots and realize a fully quantum-coherent photon-emitter interface operating in the original telecommunication band (or O-band, 1,260-1,360 nm). We record transform-limited linewidths only 8% broader than the inverse lifetime and bright 41.7-MHz emission rate under 80-MHz π-pulse excitation. These findings showcase the potential of quantum dots for scalable quantum networks.
Nanophotonics and plasmonics, Quantum dots, Quantum information, Single photons and quantum effects
Nature Reviews Materials
Large-scale, mechanically robust bioinspired confined MXene nanocomposites
Review Paper | Two-dimensional materials | 2026-04-26 20:00 EDT
Yuchen Li, Xinrui Zhang, Qunfeng Cheng
Transition metal carbides, nitrides and carbonitrides (MXenes) have attracted considerable attention since they were first reported in 2011. With their metallic-level electrical conductivity, outstanding mechanical properties and abundant surface terminal groups, MXenes have broad application potential in aerospace, energy storage and biomedicine. However, translating the superior intrinsic properties of monolayer MXene nanosheets into macroscopic nanocomposites remains challenging. This Review systematically elucidates the development of high-performance MXene nanocomposites through bioinspired confined assembly strategies. We discuss the advanced characterization of voids formed during the wet chemical assembly of MXene nanosheets and clarify the mechanisms underlying their formation. On this basis, we introduce bioinspired confined assembly strategies to reduce porosity and enhance the efficiency of interlayer load transfer, which markedly improve the macroscopic mechanical and electrical properties of MXene nanocomposites. We further outline large-scale fabrication methods for bioinspired confined MXene nanocomposites. We discuss the properties and some representative applications of MXene nanocomposites, including electromagnetic interference shielding, bone regeneration and artificial muscles. Finally, we provide our perspectives for future research directions for bioinspired confined MXene nanocomposites.
Two-dimensional materials
arXiv
Field-driven phases in a three-dimensional twisted Kitaev model for CoNb$_2$O$_6$: Interplay of frustration and spin-orbit coupling
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-04-27 20:00 EDT
The Ising chain in a transverse field stands out as a paradigmatic example for a quantum phase transition. CoNb$ _2$ O$ _6$ has been discussed as a material realization of this physics, but it was later realized that its magnetic exchange couplings are more complicated, taking the form of twisted Kitaev chains. Here we study a three-dimensional model for CoNb$ _2$ O$ _6$ , taking into account both Kitaev physics and frustrated inter-chain coupling, in applied magnetic field. Using semiclassical techniques at zero temperature, we map out the sequence of field-driven phases for arbitrary field direction; these include phases with commensurate and incommensurate inter-chain order. As a result of spin-orbit coupling, the phase diagram is extremely sensitive to small changes in the field angle. We compute static observables as well as magnetic excitation spectra in the various phases and connect our results to existing experimental data.
Strongly Correlated Electrons (cond-mat.str-el)
16 pages, 11 figures
Beyond Variational Bias: Resolving Intertwined Orders in the Hubbard Model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-04-27 20:00 EDT
Luciano Loris Viteritti, Riccardo Rende, Christopher Roth, Anirvan Sengupta, Giuseppe Carleo, Antoine Georges
The two-dimensional Hubbard model at finite doping hosts competing or intertwined orders, resulting in conflicting conclusions from different computational approaches regarding its ground state. We show that a key source of such discrepancies is the bias encoded in the variational ansatz. We consider three different Transformer backflow fermionic wave functions based on a Slater determinant, its particle-hole counterpart, and a Pfaffian, initialized without any mean-field pretraining. We show that, despite achieving nearly degenerate, state-of-the-art variational energies, each ansatz converges to a state with qualitatively different spin, charge, and pairing correlations. Upon improving accuracy via symmetry restoration and variance reduction, however, all three converge to the same physical picture: coexisting superconducting and stripe orders. These results demonstrate that variational energy alone is insufficient to identify the ground state in the presence of competing phases, and highlight the importance of tracking how correlation functions evolve as the wave function is systematically improved before drawing physical conclusions.
Strongly Correlated Electrons (cond-mat.str-el), Disordered Systems and Neural Networks (cond-mat.dis-nn), Superconductivity (cond-mat.supr-con)
10 pages, 9 figures and 3 tables
Anisotropy of spin waves in the field-polarized phase of Fe-doped MnSi
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-04-27 20:00 EDT
I. N. Khoroshiy, A. Podlesnyak, D. Menzel, M. C. Rahn, D. S. Inosov, A. S. Sukhanov, S. E. Nikitin
Chiral magnetic textures, such as skyrmions, are of great interest to the condensed matter community due to their novel transport properties. The stabilization of topologically non-trivial magnetic phases, like the skyrmion lattice in MnSi, is governed by underlying magnetic interactions which can be probed via measurements of spin-wave excitations. Here, we report high-resolution inelastic neutron scattering (INS) measurements of the spin waves in Fe-doped Mn$ _{0.9}$ Fe$ _{0.1}$ Si deep within its field-polarized ferromagnetic state. We observe non-reciprocal spin waves with a parabolic dispersion that shifts linearly with magnetic field. Crucially, the spin-wave stiffness is highly anisotropic, with values of 14.7 meV $ \rm{\mathring{A}}$ ^2$ parallel to the applied field and 7.6 meV $ \rm{\mathring{A}}$ ^2$ perpendicular to it. This pronounced anisotropy in a cubic material is inconsistent with standard theoretical models for MnSi and indicates a necessity to revise our theoretical understanding.
Strongly Correlated Electrons (cond-mat.str-el)
7 pages, 6 figures
Floquet mobility edges and transport in a periodically driven generalized Aubry-André model
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-04-27 20:00 EDT
Jayashis Das, Vatsana Tiwari, Manish Kumar, Auditya Sharma
We investigate the effect of a periodic electric field drive on the generalized Aubry-André model, also known as the Ganeshan-Pixley-Das Sarma (GPD) model, which is well known as a host of mobility edges. Our study of the Floquet spectrum of the driven GPD model uncovers the emergence of two distinct Floquet mobility edges, a delocalized–localized (DL) edge in the bounded regime, and a multifractal–localized (ML) edge in the unbounded regime. Using analytical results derived from Avila’s global theory applied to the high frequency effective Hamiltonian, together with numerical diagnostics such as the fractal dimension and inverse participation ratio, we demonstrate that these mobility edges can be effectively controlled by the amplitude and frequency of the electric field drive. We also identify drive-induced localization at specific values of the driving parameters, corresponding to dynamical localization points in the absence of quasiperiodic potential. Furthermore, the dynamical study of the periodically driven GPD model demonstrates superdiffusive to almost ballistic transport in the bounded regime corresponding to the DL edges, whereas subdiffusive transport is observed in the unbounded regime associated with the ML edges. We also analyze deviations from the high-frequency effective description by explicitly examining the low-frequency driving regime, where significant and counterintuitive deviations in both spectral properties and transport behavior are observed. Our study highlights the interplay of a quasiperiodic potential and a periodically varying electric field drive as a powerful mechanism to engineer mobility edges and control transport in systems with rich spectral features.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
20 Pages, 12 Figures
How Electrons Become Mobile in a Colossal Dielectric – Fe$_2$TiO$_5$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-27 20:00 EDT
M. L. McLanahan, A. P. Ramirez
We measure the colossal permittivity in single crystal Fe$ _2$ TiO$ _5$ using broadband spectroscopy in the frequency range 20 Hz - 1 MHz. The relaxation response is analyzed using a Debye-like model with Arrhenius activation in two different ways and yields an energy barrier of 286.1 $ \pm$ 2.8 meV. DC transport yields an activation energy of 288.8 $ \pm$ 2.8 meV. These results strongly imply that the energy barrier for localized dipole motion and itinerant charge transport originate from the same atom-level forces. A further implication is that colossal dielectric behavior is a microscopic bulk phenomenon arising from a system on brink of metallicity.
Materials Science (cond-mat.mtrl-sci)
Manuscript: 15 pages, 4 figures, 1 table. Supplemental: 11 pages, 8 figures
Apparent Planckian scattering from local polaron formation
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-04-27 20:00 EDT
Brian Yong-Ho Lee, Chaitanya Murthy
We propose a simple mechanism for apparent Planckian scattering based on local polaron formation, in which $ \Gamma_\text{tr} = \Gamma_0 + \alpha k_BT / \hbar$ with $ \alpha \sim O(1)$ emerges from quasielastic scattering without fine tuning. We provide evidence for our proposal in Monte Carlo simulations of the Holstein model with disordered electron-phonon coupling in the adiabatic limit. Our mechanism generates a finite interval of couplings in which the slope $ \alpha$ is approximately constant, coinciding with the onset of local polaron formation. In this regime, Matthiessen’s rule is dramatically violated (or obeyed, depending on one’s point of view) in that changes to the couplings, which in perturbation theory would alter the slope $ \alpha$ , instead change the intercept $ \Gamma_0$ . We conjecture that a version of our mechanism applies to any system with a dominant disordered interaction that can drive polaron formation. This potentially includes regimes of the recently introduced disordered-Yukawa-coupling strange metal models where polaron formation is not suppressed.
Strongly Correlated Electrons (cond-mat.str-el), Disordered Systems and Neural Networks (cond-mat.dis-nn)
6 pages, 2 figures (+Appendices: 5 pages, 5 figures). Comments welcome
Carrier scattering considerations and thermoelectric power factors of half-Heuslers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-27 20:00 EDT
Rajeev Dutt, Bhawna Sahni, Yao Zhao, Yuji Go, Saff E Awal Akhtar, Ankit Kumar, Sumit Kukreti, Patrizio Graziosi, Zhen Li, Neophytos Neophytou
The electronic and thermoelectric (TE) transport properties of 13 n-type and p-type half-Heusler alloys are computationally examined using Boltzmann transport. The electronic scattering times resulting from all relevant phonon interactions and ionized impurity scattering (IIS) are fully accounted for using ab initio extracted parameters. We find that at room temperature the average peak TE power factors (PF) of all materials we examine reside between 5 and 10 mW/mK$ ^2$ . We also find that IIS in combination with the long range polar optical phonon (POP) scattering are more influential in determining the electronic transport and PF over all other non-polar phonon interactions (acoustic and optical phonon transport). In fact, the combination of POP and IIS determines the thermoelectric power factor of the half-Heuslers examined on average by about 65%. The results highlight the crucial impact of Coulombic scattering process (POP and IIS) on the TE properties of half-Heusler alloys and provide profound insight for understanding transport, which can be applied widely in other complex bandstructure materials. In terms of computation expense, the computationally cheaper POP and IIS provide an acceptable first-order estimate of the power factor of these materials, while the non-polar contributions, which require more expensive ab initio calculations, could be of secondary importance.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
14 pages, 22 figures
J. Mater. Chem. A, 2026, 14, 10332
Spin-polarized Energy Density Method from Spin-Density Functional Theory
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-27 20:00 EDT
Yang Dan, Dallas R. Trinkle (Department of Materials Science and Engineering, University of Illinois, Urbana-Champaign, Urbana, Illinois, USA)
The energy density method is generalized to include spin polarization with the full formalism derived based on spin-density functional theory, which aims at decomposing the total energy into well-defined atomic energies. The method involves two steps: (1) decomposing the total energy into spin-polarized energy density functions in real space, and (2) integrating these energy densities over chosen gauge-invariant volumes for uniquely defined atomic energies, whose summation over all the atoms restores the DFT total energy up to a constant difference. This method is numerically implemented into the Vienna ab initio simulation package for the projector augmented-wave method, and is showcased with two applications. In the first application, we model the paramagnetic face-centered cubic Fe using spin special quasirandom structures; the spin energies are fit to spin cluster expansions and a deep neural network. In the second application, we calculate the atomic energy distributions of dilute magnetic semiconductor Ni-doped GaN with different dopant distances and spin configurations. This method extracts additional useful information for the study of magnetic systems with density functional theory.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
32 pages, 7 figures
Enhanced Tantalum Superconducting Resonator Performance via All-Surface Organic Monolayer Passivation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-27 20:00 EDT
Harsh Gupta, Moritz Singer, Benedikt Schoof, Anna Cattani-Scholz, Shreya Sharma, Luca Rommeis, Marc Tornow
Tantalum is a promising platform for superconducting quantum circuits, yet coherence times remain limited by dielectric losses from interfacial two-level systems (TLS), exacerbated by native oxide regrowth. Here, we implement molecular surface passivation using self-assembled organic monolayers on freshly etched tantalum and silicon in coplanar waveguide resonators. Surface characterization by contact angle, XPS, FTIR and TEM confirm the formation of ordered, nanometer-thick films that suppress oxide formation. Microwave measurements in the ~5-9 GHz range reveal internal quality factors up to 1.8x10^6 in the single-photon regime at 100 mK, representing a ~140% improvement over untreated devices with native oxide. Power and temperature dependent measurements attribute this enhancement to reduced TLS-induced losses. These results demonstrate that molecular passivation effectively engineers low-loss interfaces and provides a scalable route toward high-coherence superconducting quantum devices.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph), Quantum Physics (quant-ph)
Extended Haldane Model in The Dice Lattice: Multiple Flat-Band-Induced topological Transitions Revealed
New Submission | Other Condensed Matter (cond-mat.other) | 2026-04-27 20:00 EDT
Othmane Benhaida, Lalla Btissam Drissi, El Hassan Saidi
In this study, we examine the introduction of the Haldane model into the dice lattice by altering the flow between the next-nearest-neighbour sites. This breaks the lattice’s inversion and time-reversal symmetries. We demonstrate the presence of point-charge particle symmetries at $ \phi^c=\pi/6$ and $ 5\pi/6$ and derive the analytical expression for quasi-energies. We demonstrate that a gap closure occurs at these critical points, inducing a topological transition. This is confirmed by calculating the Berry curvature and orbital magnetic moment. A topological analysis shows that the Chern numbers of the valence band $ (\nu=0)$ , the flat band $ (\nu=1)$ and the conduction band $ (\nu=2)$ depend strongly on the relationship between the fluxes $ \phi^a $ and $ \phi^c$ . When $ \phi^c = \phi^a$ , the Chern numbers are $ (C_0, C_1, C_2) = (2, -2, 0)$ in the region $ \phi^c \in [0, \pi/6[$ , and (0, 2, -2) in the region $ \phi^c\in ]5\pi/6, \pi]$ . Conversely, when $ \phi^c \neq \phi^a$ , the topological invariants become $ (C_1, C_2) = (-1, -1)$ for $ \phi^c \in [0, \pi/6[$ , and $ (C_0, C_1, )= (1, 1)$ for $ \phi^c\in ]5\pi/6, \pi]$ . These variations reflect topological phase transitions at the critical points $ \phi^c=\pi/6$ and $ 5\pi/6$ , affecting all of the system’s bands. Furthermore, the anomalous Hall conductivity exhibits a quantized plateau of 2$ \sigma_{0}$ , as well as an unquantized tilted plateau evolving from 1.50$ \sigma_{0}$ to 1.25$ \sigma_{0}$ at the same transition points. Controlling the flux allows topological transitions to be engineered and quantum transport in the dice lattice to be optimised, offering promising prospects for reconfigurable topological devices with low dissipation and robust quantum transport.
Other Condensed Matter (cond-mat.other)
16 pages, 8 figures. Published in Annalen der Physik
Annalen der Physik 538, e202500615 (2026)
Harnessing Plasmonic Heating For Switching In Antiferromagnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-04-27 20:00 EDT
H. Y. Yuan, Yizheng Wu, Olena Gomonay
Heat waste is a bottleneck in the development of green information technologies and much effort has been devoted to suppress the heating effect in both electronic and spintronic devices. Here we take an alternative approach and show that controllable heating at the nanoscale can actually benefit information processing. In particular, we study a hybrid nanostructure consisting of a metallic square frame and an antiferromagnetic (AFM) thin film and show that the plasmonic heating can reversibly switch two perpendicularly-oriented AFM domains without the assistance of magnetic fields and electric currents. The required switching energy is at the order 1 nJ, three to six orders of magnitude lower than the current-driven AFM switching. The physical mechanism arises from the thermal-induced strain fields inside the frame, which couple to and manipulate the magnetic orientation via magnetoelastic effect. The strain field direction can be well controlled by selectively exciting the longitudinal and transverse plasmon modes by varying the polarization of the waves, which readily allows for a reversible switching of the AFM vector. Our findings provide tremendous opportunities for optically manipulating the magnetism with ultralow energy consumption and may further promote the interdisciplinary study of photonics, acoustics and spintronics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics)
7 pages, 5 figures
Long-Range Order in Coupled $D$-dimensional Kuramoto Oscillators
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-04-27 20:00 EDT
Zhongpu Qiu, Tianyi Wu, Linkai Zhang, Sheng Fang, Jun Meng, Jingfang Fan, Hugues Chaté
We show that the long-range order (LRO) strikingly emerges in systems of locally coupled $ D$ -dimensional vector Kuramoto oscillators on low-dimensional lattices ($ d=1,2$ ), but only for odd $ D$ . This parity-dependent effect is traced to two-oscillator dynamics, where odd-$ D$ units synchronize for any coupling, while even-$ D$ pairs require a finite threshold. This fundamental difference selectively seeds collective order in large-scale systems, a phenomenon demonstrated by our numerical simulations. A renormalization group analysis reveals a RG flow to a weak-coupling fixed point for $ d \le 2$ . In this limit, odd-$ D$ systems effectively map to a ferromagnetic model, developing an ordered ``hemisphere” phase, whereas even-$ D$ systems remain disordered. Our findings further reveal orientational LRO emerges in both $ d=1$ and $ d=2$ , but frequency LRO requires $ d=2$ . We contrast these results with the established behavior of models possessing continuous symmetry, highlighting how quenched disorder provides a fundamentally new route to order.
Statistical Mechanics (cond-mat.stat-mech)
Microscopic Modeling of Surface Roughness Scattering in Inversion Layers of MOSFETs Based on Ando’s Linear Model
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-04-27 20:00 EDT
A microscopic model of surface roughness (SR) scattering in inversion layers of bulk-MOSFETs based on Ando’s linear model is proposed. Taking into account the stochastic nature of roughness position induced by discontinuity of the spatial derivatives of electrostatic potential and wave-function at the semiconductor/dielectric interface, a probability density of roughness position is introduced at each atomic site. The roughness parameters in the proposed model are consistent with those from experiments, and thus, there is no discrepancy between theory and experiment. The SR scattering rate is then derived by using the Green’s function scheme, and we find that the scattering rate is intrinsically nonlocal (nondiagonal) with respect to subband indices and position. In addition, the self-consistent scattering rate greatly deviates from those obtained by Fermi’s golden rule in the regimes of strong effective fields and low electron energies. As a result, the conventional model tends to predict smaller SR-limited mobility.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Non-volatile superconducting tunnelling magnetoresistance memory enabled by exchange-field gap engineering
New Submission | Superconductivity (cond-mat.supr-con) | 2026-04-27 20:00 EDT
Sonam Bhakat, Pushpak Banerjee, Ahmedullah Aziz, Jackson Miller, Avradeep Pal
Scalable, low-dissipation memory operating below 4 K is a critical requirement for superconducting and quantum computing systems. Existing cryogenic memory technologies rely on CMOS derivatives or hybrid architectures that incur leakage, refresh overhead or limited compatibility with superconducting logic. Here we demonstrate a superconducting tunnelling magnetoresistance device that functions as a non-volatile cryogenic memory element across the full superconducting temperature range. By integrating a de Gennes spin valve with a superconducting tunnel junction in a current perpendicular-to-plane geometry, we realise exchange-field control of the superconducting energy gap. This produces two magnetically switchable gap voltages and robust quasiparticle tunnelling magnetoresistance down to 0.25 this http URL device operates at millivolt bias with nanowatt-level read power and zero standby dissipation. Its vertical junction architecture and Nb-based materials platform enable compatibility with superconducting logic and scalable cryogenic memory arrays.
Superconductivity (cond-mat.supr-con), Applied Physics (physics.app-ph)
4 figures
Uncovering long-lived relaxation channel and exciton-phonon coupling in \textrm{Ta\textsubscript{2}NiSe\textsubscript{5}} via non-degenerate pump-probe spectroscopy
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-04-27 20:00 EDT
Poulami Ghosh, Anupama Chauhan, Sidhanta Sahu, Sk Kalimuddin, Mintu Mondal, N. Kamaraju
An excitonic insulator represents a quantum phase in which spontaneous condensation of excitons leads to novel many-body phenomena. Ta$ _2$ NSi$ _5$ (TNSe), a layered narrow-gap semiconductor, has emerged as a model platform to probe these correlated excitonic phases and their underlying dynamics below 327 K. In this work, we investigate the nonequilibrium dynamics of TNSe using temperature-dependent, non-degenerate optical pump-probe spectroscopy with a 3.14 eV pump and a 1.57 eV probe, extending the accessible pump-probe delay window up to 500 ps. In addition to the well-established sub-picosecond relaxation channel ($ \sim$ 0.7- 0.9 ps) associated with carrier cooling and recombination, accompanied by exciton reformation, we uncover a much slower recovery process with a decay time of $ \sim$ 280-600~ps, significantly longer than previously reported. We attribute this unusually prolonged recovery to enhanced scattering between excitons and nonequilibrium phonons, which delays the re-establishment of equilibrium excitonic correlations. On top of this bi-exponential background, we observe two coherent phonon modes at 1.0 and 2.9 THz with distinctly different coupling behaviors. The 1.0 THz mode exhibits an order-parameter-like temperature dependence, consistent with strong coupling to the excitonic condensate in TNSe. In contrast, the 2.9 THz mode does not exhibit any discernible coupling to the excitonic order parameter, and appears to arise from anharmonic lattice dynamics associated with the structural phase transition. Together, these results elucidate the hierarchy of relaxation pathways in TNSe and highlight the importance of extending the temporal detection window in pump-probe measurements to fully capture long-lived exciton-phonon dynamics.
Strongly Correlated Electrons (cond-mat.str-el)
5 Main figures, 9 supplemental figures
QAssemble: A Pure Python Package for Quantum Many-Body Theory
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-04-27 20:00 EDT
Seongjun Mo, Dongming Li, Mancheon Han, Johan Jönsson, Byungkyun Kang, Hoonkyung Lee, Gabriel Kotliar, Sangkook Choi
QAssemble is a pure-Python package for the quantum many-body problem. It implements various functional approaches, such as tight-binding, Hartree-Fock, and GW approximations within a unified object-oriented architecture. Each physical concept–crystal structure, Hamiltonian, Green’s function, self-energy, polarizability, screened Coulomb interaction–is represented as a distinct class. The modular design prioritizes code clarity and extensibility, leveraging NumPy, SciPy, and libdlr for numerical operations. Performance-critical kernels, including the polarizability bubble, Dyson equation inversion, and lattice Fourier transforms, are systematically vectorized and combined with the discrete Lehmann representation to achieve practical efficiency within a pure-Python environment. We validate QAssemble on the electronic structure of graphene with local and non-local interactions. Furthermore, benchmarks on a five-orbital extended Hund-Hubbard model demonstrate that this strategy delivers up to a 60x speedup over traditional loop-based Matsubara implementations. QAssemble supports both batch execution for production calculations and interactive workflows for method development.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
25 pages, 4 figures, 2 tables, 2 extended data figures
Active Jurin’s law
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-04-27 20:00 EDT
Birendra Mandal, Joydip Chaudhuri
Capillary rise is one of the classical problems in fluid mechanics and is traditionally described by Jurin’s law, which balances capillary suction against hydrostatic pressure. Here we extend this classical result to active fluids, materials that generate internal stresses through microscopic energy consumption. Using the continuum theory of active nematics, we show that activity modifies the normal stress balance at the liquid-gas interface through an additional active normal stress contribution. This leads to a generalized active Jurin’s law, which can be written in dimensionless form as (H_{\infty} = 1 - \mathrm{Ja}a \xi_0), where (H{\infty}) is the dimensionless active Jurin height at equilibrium, (\mathrm{Ja}_a) is an active Jurin number comparing active stress to capillary pressure, and (\xi_0) characterizes the alignment of active constituents at the meniscus. The theory predicts that extensile and contractile active fluids can either enhance or suppress capillary rise depending on the magnitude of activity and the interfacial alignment state. From this relation we construct a phase diagram in the ((\mathrm{Ja}_a,\xi_0)) plane that delineates regimes of activity-enhanced rise, activity-suppressed rise, and complete suppression of the classical capillary state. When orientational order depends on confinement and flow, the coupling between activity and capillarity produces nonlinear equilibrium conditions that may admit multiple steady heights; linear stability analysis reveals that the overdamped dynamics selects a single stable state, whereas the inertial extension allows the possibility of activity-induced bistability. These results show that internally generated stresses fundamentally reshape one of the most classical capillary transport problems.
Soft Condensed Matter (cond-mat.soft), Fluid Dynamics (physics.flu-dyn)
A variational formulation of stochastic thermodynamics: Spatially extended systems
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-04-27 20:00 EDT
Héctor Vaquero del Pino, François Gay-Balmaz, Hiroaki Yoshimura, Lock Yue Chew
Stochastic field theories are often constructed phenomenologically, without a systematic assessment of thermodynamic consistency or local detailed balance. This may hinder a physical description of irreversibility at the field-theoretic level beyond the standard statistical formulation of stochastic thermodynamics. Here, we develop a variational formulation for thermodynamically consistent stochastic field theories by extending Hamilton’s principle of classical field theory. Introducing the second law as an axiom yields a consistent local thermodynamic structure in which novel fluctuationdissipation relations emerge naturally, ensuring local detailed balance. Remarkably, the resulting entropy production takes the same form as in standard stochastic thermodynamics, up to a reformulation in an extended phase space incorporating both configurational and thermal variables. This correspondence extends key results, including individual trajectory-level thermodynamics and fluctuation theorems. The construction is formulated within a unified geometric framework based on a generalized Lagrange-d’Alembert principle, providing a top-down connection between phenomenological modeling and thermodynamic consistency. Potential applications include thermodynamically consistent modeling of complex fluids, Lagrangian reduction by symmetry in continuum systems, and structure-preserving numerical schemes for stochastic partial differential equations.
Statistical Mechanics (cond-mat.stat-mech), Mathematical Physics (math-ph)
arXiv admin note: text overlap with arXiv:2510.01787. text overlap with arXiv:2510.01787
Theoretical prediction of strong-coupling superconductivity in a hypothetical NaAlH3 phase at ambient pressure
New Submission | Superconductivity (cond-mat.supr-con) | 2026-04-27 20:00 EDT
Izabela A. Wrona, Yinwei Li, Radoslaw Szczesniak, Artur P. Durajski
We present a comprehensive first-principles investigation of a hypothetical cubic Pm-3m phase of the ternary hydride NaAlH3, focusing on its lattice dynamics, electronic structure, and electron-phonon-mediated superconducting properties at ambient pressure. Using density functional theory and the Migdal-Eliashberg formalism, we find an exceptionally strong electron-phonon coupling ($ \lambda=2.23$ ), resulting in a superconducting critical temperature of up to 73.7 K for a Coulomb pseudopotential $ \mu^\ast = 0.1$ . Phonon dispersion calculations, complemented by ab initio molecular dynamics simulations, indicate dynamic and thermal stability within the adopted theoretical framework. The electronic structure exhibits a metallic character with substantial contributions from Al- and Na-derived states at the Fermi level. The resulting superconducting gap ratio ($ 2\Delta(0)/k_B T_c \approx 4.8$ ) and specific heat jump ($ \Delta C/\gamma T_c \approx 2.2$ ) significantly exceed BCS weak-coupling predictions, highlighting the strong-coupling nature of superconductivity in this hypothetical phase.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci)
Phys. Rev. B 113, 144511 (2026)
The antiferromagnetic Chern insulator phase in the Kane-Mele-Hubbard model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-04-27 20:00 EDT
Bao-Qing Wang, Can Shao, Takami Tohyama, Hong-Gang Luo, Hantao Lu
The emergence of the antiferromagnetic (AFM) Chern insulator (AFCI) phase in the Kane-Mele-Hubbard (KMH) model with a finite sublattice potential is investigated. The AFCI, characterized by AFM correlations coexisting with quantized Hall conductance, has long raised the question of whether it can exist in the KMH model that respects time-reversal symmetry (TRS). Using exact diagonalization, we analyze the excitation gap, anisotropic AFM correlations along the $ z$ axis and in the $ xy$ plane, and the fidelity susceptibility under twisted boundary conditions, all of which provide consistent evidence for the AFCI phase. In particular, our numerical evaluation on the (spin) Chern number reveals a breakdown of adiabatic continuity in the twist-angle space, indicating an instability toward TRS breaking driven by Hubbard-induced AFM perturbations. A modified computational scheme is further proposed, which yields a robust quantized Chern number $ C=1$ within this phase.
Strongly Correlated Electrons (cond-mat.str-el)
14 pages, 11 figures
Physical Review B 113, 165141 (2026)
The quantum harmonic oscillator in a dissipative bath of anyon pairs
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-04-27 20:00 EDT
Nils-Henrik Meyer (1), Michael Thorwart (1), Axel Pelster (2) ((1) Institut für Theoretische Physik Universität Hamburg, (2) Fachbereich Physik und Forschungszentrum OPTIMAS Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau)
We generalize the formalism of open quantum systems to introduce anyon baths. In particular, we work out a dissipative anyon bath composed of independent pairs of one-dimensional Grundberg-Hansson harmonically bound anyons, which are characterized by one statistical parameter. Using a mapping of these anyons to a bosonic bath with rescaled oscillator frequencies, we show that the original bilinear system-bath coupling assumes a particular non-polynomial form. To determine the relaxation properties, we use the imaginary-time path integral formalism together with a generalization of Wick’s theorem in the form of a smearing formula. The latter allows to approximately calculate the anyon bath spectral density, which acquires a nontrivial temperature dependence. The corresponding relaxation dynamics of the dissipative harmonic oscillator in an anyon bath is found. Well defined limits are revealed for both low and high temperatures. Anyonic features turn out to be most pronounced in the regime of intermediate temperatures.
Statistical Mechanics (cond-mat.stat-mech)
Dynamic Moiré Potentials and Robust Wigner Crystallization in Large-Scale Twisted Transition Metal Dichalcogenides
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-27 20:00 EDT
Yifan Ke, Chuanjing Zeng, Xinming Qin, Wei-Lin Tu, Wei Hu, Jinglong Yang
Understanding the dynamical evolution of large-scale moiré systems is crucial for connecting theoretical predictions with experimental observations. Here we develop a machine-learning-based workflow, integrating DeePMD and DeepH frameworks with first-principles calculations, to efficiently investigate time-dependent structural and electronic responses in twisted bilayer transition metal dichalcogenides (TMDs) with experimentally relevant moiré supercells containing over 3000 atoms. Using $ \mathrm{WS_2}$ as a representative system, we show that low-temperature lattice vibrations and relaxation deepen the moiré potential wells, narrow the lowest conduction band, and facilitate the formation of strongly localized electronic states. Based on DFT-derived moiré potentials that incorporate these dynamical effects, density-matrix-renormalization-group (DMRG) simulations reveal robust Wigner crystallization and a kagomé-patterned three-electron state, consistent with recent experimental observations. Our workflow provides a practical route for exploring large moiré supercells beyond static configurations and offers new insight into the interplay between lattice dynamics, electronic localization, and emergent correlated states in twisted two-dimensional materials.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el), Chemical Physics (physics.chem-ph), Computational Physics (physics.comp-ph)
22 pages with 4 figures in the main text, 11 pages with 15 figures in the supplementary
Electric-Field Control of Quantum Tunneling Regimes in Focused He-Ion-Beam-Irradiated Oxide Interfaces
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-04-27 20:00 EDT
Yu Chen, Maria D’Antuono, Robin Hutt, Cesar Magen, Edward Goldobin, Dieter Koelle, Reinhold Kleiner, Marco Salluzzo, Daniela Stornaiuolo
Helium focused ion beam irradiation enables the fabrication of tunnel field-effect transistors based on two-dimensional electron systems (2DESs) at an oxide this http URL resolution scanning transmission electron microscopy and strain mapping reveal localized lattice deformation confined to the irradiated regions, which act as nanoscale potential barriers. The barrier profile can be continuously tuned by electrostatic backgating at low temperature without degrading the electronic properties of the 2DES electrodes. Transport measurements demonstrate controlled access to thermionic emission, direct tunneling, and Fowler-Nordheim tunneling within a single device architecture. These results establish He FIB irradiation as a powerful tool for nanoscale functional engineering of complex-oxide interfaces and provide a platform for exploring gate-tunable quantum tunneling phenomena.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Manuscript : 10 pages,5 figures (Fig.1 to Fig.5). Supplementary: 5 pages, 5 figures (Fig.S1 to Fig.S5)
Spiral, target, stripe, and disordered waves in active six-state Potts models
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-04-27 20:00 EDT
Wave propagation can be observed in various nonequilibrium systems. In this study, we investigated the properties of several wave modes in active six-state Potts models using Monte Carlo simulations of square and hexagonal lattices. Disordered and spiral (SP) waves of six states are formed under weak and strong repulsions at nonflip contacts, respectively. The target (TG) and stripe (ST) waves were found to emerge under stronger repulsion. These three wave modes (SP, TG, and ST) can temporally coexist in small systems near the transition points but they do not switch in large systems or far from these transition points. During coarsening from randomly mixed states to ST waves, SP waves appear at an intermediate stage. The SP wave modes of three even- or odd-numbered states (states $ s=0,2,4$ or $ s=1,3,5$ ) emerge under two conditions: repulsion at the diagonal contact and attraction at nonflip contacts. Previously thought to be identical for both conditions, the wave types were found to differ, comprising forward and backward waves ($ s=1\to 3\to 5\to 1$ or $ s=1\to 5\to 3\to 1$ ), whose domain boundaries move by the two-step and four-step forward flips, respectively. The transition between the waves of the even- and odd-numbered states is first-order for both the forward and backward waves.
Statistical Mechanics (cond-mat.stat-mech), Pattern Formation and Solitons (nlin.PS)
12 pages, 13 figures
Covariant Onsager and Onsager-Machlup principles for active and inertial dynamics
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-04-27 20:00 EDT
Kento Yasuda, Bin Zheng, Zhongqiang Xiong, Zhanglin Hou, Kenta Ishimoto, Xinpeng Xu, David Andelman, Shigeyuki Komura
The Onsager principle provides a variational route to the phenomenological equations of dissipative dynamics through the minimization of the Rayleighian. We develop a covariant formulation of the Onsager principle for active systems, ensuring geometric consistency under coordinate transformations. To further incorporate thermal fluctuations, we formulate the Onsager-Machlup principle for active systems by considering the Onsager-Machlup functional and the corresponding path probability for stochastic trajectories. Requiring that the path probability obeys the detailed fluctuation theorem, we show that the extended Onsager-Machlup theory is consistent with stochastic thermodynamics. Moreover, we incorporate inertia into the variational framework and show that the proper covariant equations follow when the covariant acceleration is held fixed during the variation.
Soft Condensed Matter (cond-mat.soft)
Nature of point defects in bulk hexagonal diamond
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-27 20:00 EDT
Ling Zhu, Xuanxuan Zhang, Guliqinayi Alimu, Chen-Min Dai, Chunlan Ma, Zenghua Cai
Hexagonal diamond (HD), an exotic carbon allotrope recently synthesized in bulk form, exhibits superior mechanical properties compared to cubic diamond (CD) and holds promise for advanced industrial and quantum applications. Using first-principles calcu-lations, we systematically investigate intrinsic defects, extrinsic dopants, and defect complexes in HD. Our study shows that VC dominates intrinsic conductivity, while Ci is unstable. Among extrinsic dopants, boron acts as a benign acceptor enhancing p-type conductivity, whereas nitrogen and phosphorus serve as effective donors for n-type conductivity. Group II and Group IV dopants, however, introduce high formation energies or neutral charge states with limited impact. Furthermore, VC, MgC and XV defect com-plexes display multiple spin and charge states within the HD band gap, highlighting their potential as color centers for hosting qubits. These results not only clarify the defect physics of HD but also demonstrate its broader implications for conductivity engineering and quantum technologies.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
Surface coating induced lubrication in flowing granular materials
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-04-27 20:00 EDT
Sayali V. Chaudhary, Ashish V. Orpe
We investigate the flow of spherical, bulk granular particles down an inclined plane mixed with small-sized spherical lubricant particles using discrete element method simulations. Predefined cohesive interaction is implemented between lubricant and bulk particles, enabling the coating of the former over the latter. The overall flow rate exhibits non-monotonic dependence on lubricant content. Initially, it increases with lubricant addition, reaches a maximum at an intermediate lubricant content, and decreases for even higher lubricant content. The increase in the flow rate is attributed to a lower inter-particle friction coefficient between lubricant-coated bulk particles. The decrease in the flow rate at higher lubricant content, on the other hand, is attributed to enhanced densification and increased damping between crowded particles. Both these occurrences are examined using various flow level characteristics. The simulation results are found to be in qualitative agreement with previous experimental results. Overall, the outcome integrates novel computational insights and prior experimental results to enhance the understanding of the powder lubrication phenomena.
Soft Condensed Matter (cond-mat.soft)
12 pages, 11 figures, 2 Tables
Phys. Fluids, 38, 043332 (2026)
Accurate Nanoscale Mapping of Electric Fields across Random Grain Boundaries in Polycrystalline Oxides Using Precession-Assisted 4D-STEM
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-27 20:00 EDT
Sangjun Kang (1 and 2), Hyeyoung Cho (1 and 2), Maximilian Töllner (1 and 2), Anna Rose Nelson (2), Ziming Ding (1), Xiaoke Mu (3), Di Wang (1), Wolfgang Rheinheimer (4), Kai Wang (2), Bai-Xiang Xu (2), Jakob Konstantin Laux (2), Mahmoud Serour (2), Karsten Albe (2), Andreas Klein (2), Christian Kübel (1 and 2) ((1) Karlsruhe Institute of Technology, (2) Technical University Darmstadt, (3) Lanzhou University, (4) University of Stuttgart)
Space charge layers (SCLs) at grain boundaries play a crucial role in modulating local electric fields and influencing the functional properties of materials, such as oxygen vacancy migration and ionic conductivity in oxide ceramics. However, the direct experimental analysis of such localized electric fields and the corresponding charge distribution remains challenging. Conventional center-of-mass (CoM) analysis in scanning transmission electron microscopy differential phase contrast (STEM-DPC) is strongly affected by orientation-dependent contrast and dynamical scattering. Here, we demonstrate that combining electron beam precession with advanced post-processing, employing iterative edge detection via a Sobel filter and singular value decomposition (SVD), enables reliable and accurate, unbiased diffraction shift measurements with minimal crystallographic artefacts. The new method accurately refines the central disk position in nanobeam electron diffraction (NBED) patterns and thus significantly improves the extraction of the local electric field and corresponding charge distribution. Comparative analysis with conventional CoM methods shows superior accuracy and robustness for random grain boundaries in BaTiO3 and SrTiO3 as exemplary case studies. The experimental work is complemented by atomistic simulations to separate the electric field of the SCL from the mean inner potential difference of the grain boundary and the elemental segregation around the grain boundary. The in-depth analysis shows that our approach enables high-fidelity mapping of electromagnetic fields and their charge distribution in complex polycrystalline specimens, laying the groundwork for improved quantitative analysis using STEM-DPC.
Materials Science (cond-mat.mtrl-sci)
25 pages, 6 figures and 4 supplementary figures
Odd pathways speed up self-assembly
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-04-27 20:00 EDT
Dawid Dopierała, Luca Cocconi, Robert L. Jack, Anton Souslov
Active self-assembly can bypass equilibrium bottlenecks through external energy injection. However, generic driving typically distorts target structures and requires sustained energy input even after assembly is complete. Here, we investigate a class of non-reciprocal interactions that accelerates assembly while preserving the equilibrium Boltzmann distribution. The probability currents induced by these odd interactions reshape fundamental processes, including activated barrier crossing, soft-mode relaxation, and transitions between metastable states. In particular, these currents enhance Arrhenius rates by driving particles across otherwise inaccessible free-energy barriers. We show that this acceleration arises from an effective increase in the mobility of the reaction coordinate, mediated by non-reciprocal coupling between mechanical modes. In turn, we discover a trade-off between kinetic acceleration and power dissipation when active forces are engaged. Our results suggest a route to energy-efficient, high-fidelity self-assembly via active catalysts that transiently accelerate relaxation toward equilibrium targets and deactivate upon reaching the desired state.
Soft Condensed Matter (cond-mat.soft)
21 pages, 5 figures. Supplementary videos available at: this https URL
The influence of implantation conditions on dopant activation in Al-implanted 4H-SiC: A MD study applying an Al potential fitted to DFT barriers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-27 20:00 EDT
Sabine Leroch, Robert Stella, Andreas Hössinger, Lado Filipovic
We present molecular dynamics simulations of shallow Al implantation in 4H-SiC to clarify how implantation temperature and dose control defect evolution and dopant activation during early annealing. Using the Gao-Weber potential together with a reparameterized Morse Al-SiC interaction fitted to DFT migration and kick-in/out barriers, we find that higher implantation temperature reduces Frenkel-pair production and suppresses extended amorphous pockets. Yet at high doses (>1e20 cm^-3), annealing shows non-monotonic behavior: samples implanted at 900 K form larger, more stable interstitial clusters than those implanted at 500 K. These clusters trap Al and lower substitutional incorporation. Within MD-accessible times, the fraction of lattice-site Al is therefore higher after 500 K implantation despite better as-implanted crystallinity at 900 K. After annealing, two regimes emerge around the Al solubility limit: a low-dose regime dominated by isolated point defects and small complexes, and a high-dose regime with clustering and planar-defect formation that is strongly temperature dependent. The results explain the experimentally observed activation window (500-900 K) and indicate a kinetic route in which controlled nanoscale amorphization improves activation through regrowth-assisted incorporation while limiting extended defects. We also identify a new Al diffusion path and a carbon-antisite kick-out activation mechanism, both confirmed by DFT-NEB.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
Comparative Silane Surface Functionalization Strategies for Enhanced Bloch Surface Wave Biosensing of Anti-SARS-CoV-2 Antibodies
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-04-27 20:00 EDT
Agostino Occhicone, Alberto Sinibaldi, Paola Di Matteo, Daniele Chiappetta, Riccardo Guadagnoli, Peter Munzert, Francesco Michelotti
Surface functionalization plays a decisive role in the performance of biosensors, as it governs the efficiency and stability of biomolecule immobilization at the sensor interface and, consequently, the overall performance of the biosensing platforms. In this work, we present a comparative study of three organosilane chemistries - APTES, APDMS, and CPTES - applied to a SiO2 terminated 1D photonic crystal able to sustain Bloch surface waves and designed to operate as optical biosensors in both label free and fluorescence enhanced modes. Each chemistry was evaluated through a standardized label-free protocol based on the interaction between immobilized SARS CoV 2 spike protein and its corresponding antibodies, enabling quantitative assessment of binding efficiency, nonspecific adsorption, and signal repeatability. CPTES exhibited the most favorable balance between specific signals, reduced variability, and low nonspecific adsorption. The three chemistries were subsequently tested in fluorescence mode for the detection of anti SARS CoV 2 IgG antibodies in human serum, demonstrating the suitability of BSW enhanced fluorescence for rapid serological analysis. Overall, the study identifies CPTES as the most robust and reproducible functionalization strategy among the three investigated for BSW biosensing and highlights the potential of the platform for fast, sensitive detection of clinically relevant antibodies.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph), Optics (physics.optics)
Main manuscript: 19 pages, 12 figures, 2 tables. Supplementary Information: 4 pages, 3 figures
Long-Range Correlated Random Matrices
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-04-27 20:00 EDT
Abbas Ali Saberi, Roderich Moessner
Motivated by the importance ascribed to correlations in random matrices used to model phenomena in various scientific disciplines, we report how algebraic correlations between matrix elements affect the eigenvalue statistics and spectral density of random matrices. These correlations, introduced through a long-range correlated percolation model, decay as a power law $ \propto r^{-2H}$ , with exponent $ H > 0$ . As $ H$ varies, both the eigenvalue distribution and excess kurtosis undergo qualitative changes. At the threshold $ H_c = 3/4$ , characterized by emergent Gaussian statistics, a sign change in excess kurtosis marks a transition from a fat-tailed generalized $ t$ -distribution to one that gradually approaches the standard semicircle law for $ H \gg H_c$ . Our analytical results, based on scaling analysis and supported by extensive numerical simulations, provide clear predictions and uncover novel spectral regimes in random matrix theory. Our results connect techniques from statistical physics, percolation theory, and random matrix analysis, offering a new perspective on universality in correlated ensembles.
Statistical Mechanics (cond-mat.stat-mech), Other Condensed Matter (cond-mat.other), Mathematical Physics (math-ph), Data Analysis, Statistics and Probability (physics.data-an)
7 pages, 5 figures
Electrostatic-Elastic Softening and Ultraviolet Instability Driven by Non-DLVO Interactions in Charged Colloidal Crystals
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-04-27 20:00 EDT
Colloidal crystals permeated by mobile ions exhibit a coupling between electrostatic and elastic degrees of freedom that renormalizes the effective screening length and induces wave-vector-dependent elastic softening. Building on a recently proposed continuum model [\textit{Commun. Theor. Phys.} \textbf{77}, 055602 (2025)], we perform a rigorous Gaussian fluctuation analysis to elucidate the stability limits of the homogeneous phase. By integrating out the electrostatic fluctuations, we derive the effective elastic modulus $ \Gamma(q)$ as a function of wave vector $ q$ . We show that the long-wavelength modulus $ \Gamma(0)$ remains identically equal to the bare modulus $ \beta K$ , protected by perfect ionic screening. In contrast, the short-wavelength modulus $ \Gamma(q\to\infty) = \beta K(1-\xi)$ softens as the electrostatic-elastic coupling $ \xi \equiv 2\beta n_0 v_0^2 K$ increases, vanishing at a critical value $ \xi=1$ . For $ \xi>1$ , the fluctuation spectrum exhibits a negative eigenvalue for all wave vectors $ q > q_c = \kappa_0/\sqrt{\xi-1}$ , signaling an ultraviolet instability of the uniform phase. In a real colloidal crystal, this divergence is regulated by the discrete lattice cutoff $ q_{\max}\sim\pi/a$ , confining the physical instability to a finite band $ q_c < q < q_{\max}$ . The macroscopic limit $ q\to 0$ remains unconditionally stable for all $ \xi$ . The transition at $ \xi=1$ thus marks the onset of short-wavelength mechanical failure, while macroscopic elastic stiffness remains intact. Our analysis clarifies the proper physical interpretation of the minimal coupling model and provides a consistent picture of how non-DLVO interactions can drive local structural collapse in charged colloidal crystals.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci), Statistical Mechanics (cond-mat.stat-mech)
6 pages, 2 figures
Classifying magnons in itinerant ferromagnets from linear response TDDFT: Fe, Ni and Co revisited
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-27 20:00 EDT
Thorbjørn Skovhus, Thomas Olsen
The magnetic excitation spectrum of itinerant magnets exhibits rich and complex spectral features that often complicate interpretation of the underlying physics. For perturbations in the long wavelength limit, one obtains a well defined pole at zero frequency in the spectral function, the Goldstone magnon. However, for optical modes and finite wavevectors, the magnon spectrum may become damped, exhibit branching, or be completely washed out. In the present work, we show how the physical mechanism of all such features can be understood from careful analysis of the eigenmodes of the many-body spectral function. We perform first principles computations of elemental itinerant ferromagnets using a novel implementation of the linear response time-dependent density functional theory (LR-TDDFT) framework and classify the collective nature of individual spectral features based on the self-enhancement function, the product of the noninteracting Kohn-Sham susceptibility and the exchange-correlation kernel. In particular, we distinguish between coherent and incoherent collective excitations, depending on whether the real part of the self-enhancement function crosses unity at the spectral peak of the magnon, which may or may not be subject to Landau damping as quantified by the imaginary part. Classifying the computed magnon spectra accordingly, we observe coexistence of coherent magnon branches in bcc-Fe, as well as decoherence of the primary magnon branch in fcc-Ni for wave vectors near the BZ boundary where incoherent valley magnons instead carry substantial spectral weight. The analysis also naturally leads to a definition of the many-body Stoner spectrum and allows us to quantify the binding energy of the Stoner pair excitations.
Materials Science (cond-mat.mtrl-sci)
27 pages, 20 figures, 3 tables
Magnetoelastic Waves in Ferromagnetic Thin Films Mediated by Dipolar Interactions
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-27 20:00 EDT
Hiroki Yoshida, Ryohei Kono, Manato Fujimoto, Motoki Asano, Daiki Hatanaka, Kei Yamamoto, Shuichi Murakami
Magnetoelastic coupling mediated by magnetic dipolar interactions is theoretically investigated in ferromagnetic thin films under an in-plane magnetic field. We develop a theoretical description that incorporates dipolar fields derived from Maxwell’s equations in the presence of elastic deformations. The resulting coupled equations of motion predict hybridization between magnetostatic and Lamb waves. Numerical calculations for a yttrium iron garnet (YIG) film reveal anti-crossings in the dispersion relations, with hybridization gaps ranging from $ 0.1$ to several MHz.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
4+4 pages, 2 figures
Mean-Field Theory for the Three-State Active Lattice Gas Model
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-04-27 20:00 EDT
Ana L. N. Dias, Ronald Dickman, Tiago Venzel Rosembach
We develop a mean-field description including spatial structure for a simplified version of the three-state active matter model studied by Venzel et al. (Phys. Rev. E 110, 014109 (2024)). The resulting triangular lattice of coupled nonlinear differential equations are integrated numerically using a fourth-order Runge-Kutta scheme. Starting from various ordered initial configurations, we probe the stability of the corresponding stationary states, revealing the presence of various high-density ordered structures in the density(\r{ho})-noise({\eta}) plane. The results are compared with Monte Carlo simulations of the simplified model, yielding, in certain cases, unexpected transitions between ordered configuration types.
Statistical Mechanics (cond-mat.stat-mech)
34 pages, 20 figures
Micromorphic effects in an octet truss lattice
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-27 20:00 EDT
Elastic wave dispersion is studied in an octet truss lattice and compared with a designed rib lattice known to exhibit strong Cosserat elastic effects. Dispersion entails variation of wave speed with frequency. The phenomenon is experimentally investigated by exciting standing waves in specimens of different length at discrete frequencies. At lower frequencies corresponding to long wavelengths, wave propagation is classically non-dispersive. As wavelength approaches a small multiple of the rib length, dispersion is observed. The material exhibited cut-off frequencies above which no signals were propagated. The physical origin of the dispersion and cut-off is resonance of the ribs. Interpreted as micromorphic continua, cellular solid behavior reveals elastic constants associated with flexibility of the unit cell in comparison with that of the overall material.
Materials Science (cond-mat.mtrl-sci)
Valley enhanced Rabi frequency in n-type planar Silicon-MOS quantum dot
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-04-27 20:00 EDT
Xunyao Luo, Xander Peetroons, Tsung-Yeh Yang, Ruben M. Otxoa, Normann Mertig, Sofie Beyne, Julien Jussot, Yosuke Shimura, Clement Godfrin, Bart Raes, Roy Li, Roger Loo, Sylvain Baudot, Stefan Kubicek, Shuchi Kaushik, Danny Wan, Kristiaan De Greve, Takuma Kuno, Takeru Utsugi, Noriyuki Lee, Itaru Yanagi, Toshiyuki Mine, Satoshi Muraoka, Hideo Arimoto, Shinichi Saito, Digh Hisamoto, Ryuta Tsuchiya, Hiroyuki Mizuno, Charles Smith, Andrew Ramsay
Electron spin resonance spectroscopy (ESR) of a single electron in planar Si-MOS quantum dot is reported in the vicinity of a valley level anti-crossing. A number of one and two-photon resonances are observed due to mixing of magnetic spin-flip and electric valley-flip transitions. This allows the reconstruction of the energy-level diagram of a four state system with two valley and two spin states. Near the anti-crossing, an enhancement of the Rabi frequency is observed. This is attributed to an electric-dipole transition activated by admixing of the upper energy level due to inter-valley spin coupling. The electric-dipole transition may be driven via capacitive coupling between the ESR antenna, and the confinement gate. To characterize spin-valley coupling responsible for the enhancement, we measure the anisotropy of the g-factor difference between the two valley states, the mean g-factor and the inter-valley spin coupling for both in and out-of-plane magnetic fields. The inter-valley spin coupling is strongly modulated by the direction of the B-field, and is strongest for out-of-plane B-field, consistent with an in-plane spin-valley field. In principle, this strong Electric dipole spin resonance (EDSR) effect could be utilized for fast all-electrical spin control in small-scale devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
15 pages, 6 figures
Corner Majorana states in semi-Dirac
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-04-27 20:00 EDT
M. García Olmos, Y. Baba, R. A. Molina, M. Amado
Proximity-induced superconductivity in low-dimensional systems offers a powerful pathway to engineer topological superconducting phases in, otherwise, non-superconducting systems. These exotic phases are of fundamental and technological interest due to the presence of robust zero-energy modes, the Majorana bound states. In this work, we propose a theoretical framework to realize Majorana bound states from the edge states of a two-dimensional semi-Dirac system. This anisotropic system, under specific conditions, can host non-chiral edge states that propagate only along particular edges, effectively forming separated one-dimensional channels. We show that the interplay between Rashba spin-orbit coupling and a Zeeman field on this setup provides the right conditions to get an effective p-wave pairing between the edge states by proximity with a s-wave superconductor. In finite geometries, each edge can independently undergo a topological phase transition into a one-dimensional topological superconductor and give rise to four zero-energy modes localized at the strip corners. At low energies, the edge states subspace admits a description in terms of coupled Kitaev chains, providing a clear picture of the origin, robustness, and tunability of the corner Majorana modes. Our results establish semi-Dirac materials as a natural platform for realizing Majorana modes in two dimensions without relying on engineered nanostructures, vortices, or crystalline higher-order topology.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con), Quantum Physics (quant-ph)
16 pages, 8 figures
Influence of Ni Doping on the Structural, Morphological, Optical, and Electrical Properties of Nanocrystalline Cd1-xMnxS Thin Films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-27 20:00 EDT
Himanshu Sharma Pathok, Padma Pani Shahu, Himanshu Kalita, Prasanta Kumar Saikia
Ni-doped Cd1-xMnxS (x=0.4) thin films were prepared via a cost-effective chemical bath deposition (CBD) method to investigate their suitability for optoelectronic applications. Incorporation of a secondary transition metal such as Ni is expected to influence lattice strain, defect density, and electronic structure through ionic size effects and sp-d exchange interactions, thereby providing an additional degree of freedom for tuning the properties of Cd1-xMnxS-based ternary systems. X-ray diffraction (XRD) analysis confirmed the cubic zinc blende structure of the Cd1-xMnxS crystal, which was further corroborated by high-resolution transmission electron microscopy (HRTEM). Crystallinity increases where as microstrain and dislocation density found to be decreases as the doping concentration of Ni increases. Field emission scanning electron microscopy (FESEM) analysis revealed uniform, dense, and crack-free films with grain size increasing as a function of Ni content, and the FESEM cross-sectional images indicated a nearly constant thickness in the range of 181.2-189.1 nm. The films exhibited high optical transmittance (75-90%) in the visible and near-infrared (NIR) regions. The optical band gap decreases from 2.72 to 2.62 eV as the Ni concentration increases from 1% to 4%. Current-voltage (I-V) measurements revealed enhanced electrical conductivity, which further increased under illumination, confirming the photoconducting nature of the films. These results demonstrate that Ni doping effectively tunes the properties of Cd1-xMnxS thin films, highlighting their potential as efficient window layer materials for thin-film solar cells and related optoelectronic devices.
Materials Science (cond-mat.mtrl-sci)
39 pages, 19 figures
Pulse Shaping to Mitigate the Impact of Device Imperfections in Field-Free Switching Using Combined Spin-Orbit and Spin-Transfer Torques
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-04-27 20:00 EDT
Kuldeep Ray, Jérémie Vigier, Sylvain Martin, Chloé Bouard, Nicolas Lefoulon, Marc Drouard, Gilles Gaudin
Combining spin-orbit (SOT) and spin-transfer torques (STT) provides a practical approach for field-free switching in spin-orbit torque magnetic random-access memory (SOT-MRAM), a prerequisite for industrial deployment, but can compromise reliability through phenomena such as backhopping, especially in top-pinned stacks commonly used for SOT-MRAM. We investigate the write error rate (WER) of combined SOT + STT switching in top-pinned devices that are not optimized for STT switching. Experiments reveal clear indications of STT-induced backhopping and a pronounced field-free SOT switching asymmetry between AP-to-P and P-to-AP transitions. Our macrospin model, using two coupled Landau Lifshitz Gilbert equations for the free and the reference layers, qualitatively reproduces this asymmetry and reveals an intermediate loss-of-determinism regime in addition to the well-known backhopping region. Based on these simulations, we propose mitigation strategies and experimentally demonstrate that STT pulse shaping reduces WER and improves switching robustness in the presence of device imperfections.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph)
Marie Skłodowska-Curie Actions, H2020-MSCA-ITN-2020; Project acronym SPEAR; Grant Agreement No. 955671
Resonance Frequency Shift Measurements of SRF Cavities at DESY
New Submission | Superconductivity (cond-mat.supr-con) | 2026-04-27 20:00 EDT
Rezvan Ghanbari, Thorsten Buettner, Wolfgang Hillert, Karol Kasprzak, Tom Krokotsch, Ricardo Monroy-Villa, Detlef Reschke, Lea Steder, Alexey Sulimov, Hans Weise, Marc Wenskat, Mateusz Wiencek, Jonas Wolff
The variation of the resonance frequency and intrinsic quality factor of superconducting radio-frequency cavities during the transition from the superconducting to the normal-conducting state provides essential insight into the fundamental superconducting properties of the cavity material. Investigating these transition dynamics is crucial for the continued advancement of niobium cavities whose near-surface regions are intentionally modified through the controlled introduction of interstitial atoms, such as oxygen and nitrogen, leading to the emergence of several novel behaviors whose underlying mechanisms are not yet fully understood. This work reports on the development and commissioning of a dedicated frequency-shift measurement setup. In its initial implementation, the system establishes a precise framework for determining the electron mean free path within both the superconducting penetration depth and the normal-conducting skin depth. It further enables investigation of an anomalous dip in the temperature dependence of the frequency shift near the critical temperature in cavities containing interstitial atoms in the near-surface lattice, a novel phenomenon previously reported in the literature. A recent upgrade, currently in the final stage of validation, significantly improves measurement accuracy and reproducibility. The improved setup enables comprehensive studies of the frequency shift and quality factor over the full temperature range above 7 K, contributing to a deeper understanding of the superconducting properties.
Superconductivity (cond-mat.supr-con), Accelerator Physics (physics.acc-ph)
Anomalous Mean-Squared Displacement in Quantum Active Matter from a Wigner Phase-Space Framework
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-04-27 20:00 EDT
Sangyun Lee, Yehor Tuchkov, Alexander P. Antonov, Benno Liebchen, Hartmut Löwen, Giovanna Morigi, Michael te Vrugt
Active matter is driven out of equilibrium by a local influx of energy. While classical active matter has been extensively studied, the extension of active matter concepts to quantum systems has been explored far less. In this work we develop a full quantum description based on the Wigner function. By introducing a hybrid Wigner master equation that incorporates classical active motion and quantum degrees of freedom, we compute the quantum mean-squared displacement (MSD) using established techniques from classical active matter. We analytically derive the time dependence of the MSD and clarify the conditions under which the characteristic scaling with time $ \mathrm{MSD}\sim t^{6}$ emerges. We further show that, for certain parameter and initial conditions, the MSD can exhibit an even steeper scaling regime $ \mathrm{MSD}\sim t^{7}$ , and we examine the robustness of these behaviors against quantum fluctuations of the initial state.
Soft Condensed Matter (cond-mat.soft), Quantum Physics (quant-ph)
24 pages, 9 figures
Accurate calculation of Wannier centers, position matrix, and composite operators using translationally equivariant and higher-order finite differences
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-27 20:00 EDT
Jae-Mo Lihm, Minsu Ghim, Seung-Ju Hong, Cheol-Hwan Park
The momentum-space derivatives of Bloch wavefunctions are essential for studying quantum geometry and the equilibrium and response properties of solids. In practical first-principles calculations, these derivatives are obtained via Wannier interpolation of position and related composite matrices. These matrices are initially evaluated on a coarse k-point grid using finite-difference approximations and then interpolated to a dense grid. The accuracy of the finite-difference approximation directly impacts the convergence and reliability of the result. In this work, we present two key improvements to the finite-difference calculation of position and composite operators for Wannier interpolation. First, we formulate a translationally equivariant scheme that preserves the underlying symmetries of the system and significantly reduces finite-difference errors. Second, we introduce a higher-order finite-difference approach that yields a more accurate approximation of the k-space derivatives by systematically increasing the convergence rate. From a real-space perspective, these improvements correspond to better approximations of the position operator at the locations of the Wannier functions. We also present a generalization of the finite-difference scheme, which may reduce the number of finite-difference points while maintaining accuracy. We demonstrate the effectiveness of our methods by applying them to the calculation of Wannier centers and spreads, electric polarization, off-diagonal position matrix elements, orbital magnetization, and spin Hall conductivity. Our results demonstrate significant reductions in finite-difference errors, elimination of symmetry-violating errors, and improved convergence with respect to k-point sampling. These methods have been implemented in the open-source packages and can be readily adopted in other Wannier-based codes with minimal computational overhead.
Materials Science (cond-mat.mtrl-sci)
Exact relations between the density-density correlators of states in a spin multiplet
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-04-27 20:00 EDT
We present exact identities relating the pair-correlation functions and static structure factors of states in a spin multiplet. This allows us to compute these density-density correlation functions of all members of the multiplet using just these correlation functions of the highest-weight state. We apply these relations to obtain energies for many fractional quantum Hall (FQH) states. In particular, we analytically compute the energies of the Halperin-$ (1,1,1)$ state as a function of density imbalance and layer separation, and numerically evaluate these energies for many other FQH states.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
9 pages, 1 figure
Strain engineering of Andreev spin qubits in Germanium
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-04-27 20:00 EDT
Vittorio Coppini, Patrick Del Vecchio, Antonio L. R. Manesco, Anton Akhmerov, Valla Fatemi, Bernard van Heck, Stefano Bosco
Planar germanium heterostructures are promising hosts for hybrid quantum devices due to their compatibility with superconductors, low material disorder, and relaxed fabrication constraints. Also, the potentially low density of nuclear spins and strong spin-orbit interaction make germanium attractive for coherent spin physics. However, recent microwave spectroscopy experiments were unable to resolve a spin-splitting of bound states in germanium Josephson junctions, the prerequisite for defining and controlling Andreev spin qubits. Here, we argue that compressive strain is the key mechanism suppressing spin splitting in current devices. Furthermore, we propose unstrained and tensile-strained heterostructures, fully compatible with state-of-the-art growth technology, that significantly enhance the relevant spin-orbit effect. By numerically simulating ballistic Josephson junctions, we predict spin splittings comfortably in the GHz range, more than 2 orders of magnitude larger than compressively strained cases, and all-electric quantum gates in a hundred nanoseconds. Our results establish strain engineering as a key design principle for realizing Andreev spin qubits in germanium-based devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
20 pages, 10 figures
Alterations in Conformations of Poly(3-hexylthiophene) on Au(111) Induced by Annealing
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-04-27 20:00 EDT
Anmol Arya, François Vonau, Solomon L. Joseph, Thomas Pfohl, Silvia Siegenführ, Laurent Simon, Günter Reiter
Employing high-vacuum electrospray deposition and scanning tunneling microscopy, we investigated how individual poly(3-hexylthiophene) (P3HT) chains navigated on the periodic energy landscape of a reconstructed Au(111) surface. The resulting polymer conformations were governed by the interplay between the periodically corrugated substrate, in particular the depth and regularity of the modulated surface potential, and thermal energy. On a regularly reconstructed surface, annealing at °C provided sufficient energy for chain segments to overcome energy barriers of the corrugated surface potential landscape, allowing monomers along the chain to experience a strong thermodynamic driving force toward the low-energy valleys on the surface. The adsorbed polymers adopted a state where the polymer conformations were replicating the herringbone pattern. By contrast, on an irregularly reconstructed surface, the correspondingly disordered potential landscape yielded a diverse mix of coiled polymer chains performing a two-dimensional random walk and collapsed chains located in troughs of the energy landscape. Intriguingly, annealing at °C forced polymers to form clusters of many chains. Our results establish that thermal energy and substrate topography represent control parameters for altering polymer conformations, providing a mechanistic framework for rationally designing polymer nanostructures at the molecular level.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
Replica Tensor Train
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-04-27 20:00 EDT
Miha Srdinsek, Gabriel Gouraud, Xavier Waintal
We describe a numerical many-body technique that is based on both tensor networks and quantum Monte Carlo. The variational ansatz is a tensor network that can harvest volume-law entanglement. It is constructed from a tensor train to which one applies a set of non-local operators that force several indices of the tensor train to represent the same physical index, hence its name – replica tensor train (RTT). From the tensor network toolbox, it inherits the possibility to make linear combinations of these states and apply a certain class of operators. We can therefore find the ground-state of a local Hamiltonian in a purely algebraic way as in standard tensor network algorithms – i.e. without using gradient descent methods. On the other hand, the volume-law structure forbids calculating physical observables directly. In much the same way as on a quantum computer where one can prepare a state but can only sample it at the end, here we have to use Markov Chain Monte Carlo to compute the observables. We further show that the approach can be extended to build Krylov-subspace ground-state methods within the variational manifold. We illustrate the different algorithms on a two-dimensional spin model with a transverse magnetic field, which can be solved by this approach at low computational cost.
Strongly Correlated Electrons (cond-mat.str-el), Disordered Systems and Neural Networks (cond-mat.dis-nn), Quantum Physics (quant-ph)
18 pages, 6 figures, 1 table
Mechanical Scaling Laws and Deformation Behavior of Nanoporous Tantalum Microparticles
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-27 20:00 EDT
J.I. Ramallo, N. Vázquez von Bibow, M.A. Monclús, I. McCue, M.C. Fuertes, C.J. Ruestes
The mechanical scaling laws of dealloyed nanoporous metals depart from classical Gibson-Ashby predictions for open-cell foams due to a decreased connectivity in their solid network. However, these scaling relations have been established almost exclusively on nanoporous gold produced by electrochemical dealloying, and it is an outstanding question whether the relations apply to nanoporous networks fabricated by other dealloying methods. Here, we investigate the mechanical response of single-crystalline nanoporous tantalum (np-Ta) produced by liquid metal dealloying (LMD) a TiTa alloy in molten CuBi. Nanoindentation of individual microparticles yields an elastic modulus of 10-30 GPa and a hardness of 0.3-1.1 GPa, both scaling with the solid volume fraction in agreement with Gibson-Ashby predictions. This stiffness-density response of np-Ta departs from previous reports on nanoporous gold and is attributed to enhanced ligament connectivity enabled by the thermodynamics of the CuBi metal bath. Molecular dynamics simulations reveal dislocation-dominated plasticity during indentation of np-Ta, consistent with scanning electron microscopy observations of limited densification beneath the indents, ruling out unusual deformation mechanisms as an origin of the observed scaling. These findings identify solvent chemistry in LMD as a tunable lever for ligament connectivity, and thus for the mechanical response of nanoporous metals.
Materials Science (cond-mat.mtrl-sci)
Thermometry for a Kagome Lattice Dipolar Rydberg Simulator
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-04-27 20:00 EDT
Erik Fitzner, Igor Lesanovsky, Björn Sbierski
We propose an accurate thermometry approach for Rydberg atom tweezer arrays combining data from correlation and local susceptibility measurements with a theoretical high-temperature expansion method for dynamic spin correlations. We apply our approach to a recent quantum simulation experiment [Bornet et al., arXiv 2602.14323] realizing an anti-ferromagnetic dipolar spin-1/2 XY model on the Kagome lattice. We obtain T=0.55J and S/N=0.67 ln2 for temperature and entropy respectively, showing that further experimental efforts are required to reach the putative quantum spin liquid regime.
Quantum Gases (cond-mat.quant-gas), Strongly Correlated Electrons (cond-mat.str-el)
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