CMP Journal 2025-02-06
Statistics
Nature: 1
Science: 13
Physical Review Letters: 18
Physical Review X: 1
arXiv: 71
Nature
Granzyme K activates the entire complement cascade
Original Paper | Autoimmunity | 2025-02-05 19:00 EST
Carlos A. Donado, Erin Theisen, Fan Zhang, Aparna Nathan, Madison L. Fairfield, Karishma Vijay Rupani, Dominique Jones, Kellsey P. Johannes, Jennifer Albrecht, Jennifer H. Anolik, William Apruzzese, Jennifer L. Barnas, Joan M. Bathon, Ami Ben-Artzi, Brendan F. Boyce, David L. Boyle, S. Louis Bridges Jr., Vivian P. Bykerk, Debbie Campbell, Arnold Ceponis, Adam Chicoine, Michelle Curtis, Kevin D. Deane, Edward DiCarlo, Laura T. Donlin, Patrick Dunn, Andrew Filer, Hayley Carr, Gary S. Firestein, Lindsy Forbess, Laura Geraldino-Pardilla, Susan M. Goodman, Ellen M. Gravallese, Deepak Rao, Peter K. Gregersen, Joel M. Guthridge, Maria Gutierrez-Arcelus, V. Michael Holers, Diane Horowitz, Laura B. Hughes, Lionel B. Ivashkiv, Kazuyoshi Ishigaki, Judith A. James, Joyce B. Kang, Gregory Keras, Amit Lakhanpal, James A. Lederer, Miles J. Lewis, Yuhong Li, Katherine Liao, Arthur M. Mandelin II, Ian Mantel, Kathryne E. Marks, Mark Maybury, Andrew McDavid, Mandy J. McGeachy, Joseph R. Mears, Nida Meednu, Nghia Millard, Larry Moreland, Saba Nayar, Alessandra Nerviani, Dana E. Orange, Harris Perlman, Costantino Pitzalis, Javier Rangel-Moreno, Karim Raza, Yakir Reshef, Christopher Ritchlin, Felice Rivellese, William H. Robinson, Laurie Rumker, Ilfita Sahbudin, Saori Sakaue, Jennifer A. Seifert, Dagmar Scheel-Toellner, Anvita Singaraju, Kamil Slowikowski, Melanie Smith, Darren Tabechian, Paul J. Utz, Kathryn Weinand, Dana Weisenfeld, Michael H. Weisman, Qian Xiao, Zhu Zhu, Zhihan J. Li, Andrew Cordle, Aaron Wyse, Soumya Raychaudhuri, Daniel F. Dwyer, A. Helena Jonsson, Michael B. Brenner
Granzymes are a family of serine proteases mainly expressed by CD8+ T cells, natural killer cells, and innate-like lymphocytes1. Although their primary function is thought to be the induction of cell death in virally infected and tumor cells, accumulating evidence indicates certain granzymes can elicit inflammation by acting on extracellular substrates1. Recently, we found that the majority of tissue CD8+ T cells in rheumatoid arthritis (RA) synovium and in inflamed organs across other diseases express granzyme K (GZMK)2, a tryptase-like protease with poorly defined function. Here, we show that GZMK can activate the complement cascade by cleaving C2 and C4. The nascent C4b and C2b fragments form a C3 convertase that cleaves C3, enabling assembly of a C5 convertase that cleaves C5. The resulting convertases generate all the effector molecules of the complement cascade: the anaphylatoxins C3a and C5a, the opsonins C4b and C3b, and the membrane attack complex. In RA synovium, GZMK is enriched in regions with abundant complement activation, and fibroblasts are the major producers of complement proteins that serve as substrates for GZMK-mediated complement activation. Further, Gzmk-deficient mice have less severe arthritis and dermatitis with concomitant decreases in complement activation. Our findings describe the discovery of a previously unidentified mechanism of complement activation that is entirely driven by lymphocyte-derived GZMK. Given the widespread abundance of GZMK-expressing T cells in tissues in chronic inflammatory diseases, GZMK-mediated complement activation is likely to be an important contributor to tissue inflammation in multiple disease contexts.
Autoimmunity, CD8-positive T cells, Chronic inflammation, Complement cascade, Immunology
Science
The Silene latifolia genome and its giant Y chromosome
Research Article | Evolution | 2025-02-06 01:58 EST
Carol Moraga, Catarina Branco, Quentin Rougemont, Pavel Jedlička, Eddy Mendoza-Galindo, Paris Veltsos, Melissa Hanique, Ricardo C. Rodríguez de la Vega, Eric Tannier, Xiaodong Liu, Claire Lemaitre, Peter D. Fields, Corinne Cruaud, Karine Labadie, Caroline Belser, Jerome Briolay, Sylvain Santoni, Radim Cegan, Raquel Linheiro, Gabriele Adam, Adil El Filali, Vinciane Mossion, Adnane Boualem, Raquel Tavares, Amine Chebbi, Richard Cordaux, Cécile Fruchard, Djivan Prentout, Amandine Velt, Bruno Spataro, Stephane Delmotte, Laura Weingartner, Helena Toegelová, Zuzana Tulpová, Petr Cápal, Hana Šimková, Helena Štorchová, Manuela Krüger, Oushadee A. J. Abeyawardana, Douglas R. Taylor, Matthew S. Olson, Daniel B. Sloan, Sophie Karrenberg, Lynda F. Delph, Deborah Charlesworth, Aline Muyle, Tatiana Giraud, Abdelhafid Bendahmane, Alex Di Genova, Mohammed-Amin Madoui, Roman Hobza, Gabriel A. B. Marais
In many species with sex chromosomes, the Y is a tiny chromosome. However, the dioecious plant Silene latifolia has a giant ~550-megabase Y chromosome, which has remained unsequenced so far. We used a long- and short-read hybrid approach to obtain a high-quality male genome. Comparative analysis of the sex chromosomes with their homologs in outgroups showed that the Y is highly rearranged and degenerated. Recombination suppression between X and Y extended in several steps and triggered a massive accumulation of repeats on the Y as well as in the nonrecombining pericentromeric region of the X, leading to giant sex chromosomes. Using sex phenotype mutants, we identified candidate sex-determining genes on the Y in locations consistent with their favoring recombination suppression events 11 and 5 million years ago.
Rapid and dynamic evolution of a giant Y chromosome in Silene latifolia
Research Article | Evolution | 2025-02-06 01:58 EST
Takashi Akagi, Naoko Fujita, Kenta Shirasawa, Hiroyuki Tanaka, Kiyotaka Nagaki, Kanae Masuda, Ayano Horiuchi, Eriko Kuwada, Kanta Kawai, Riko Kunou, Koki Nakamura, Yoko Ikeda, Atsushi Toyoda, Takehiko Itoh, Koichiro Ushijima, Deborah Charlesworth
Some plants have massive sex-linked regions. To test hypotheses about their evolution, we sequenced the genome of Silene latifolia, in which giant heteromorphic sex chromosomes were first discovered in 1923. It has long been known that the Y chromosome consists mainly of a male-specific region that does not recombine with the X chromosome and carries the sex-determining genes and genes with other male functions. However, only with a whole Y chromosome assembly can candidate genes be validated experimentally and their locations determined and related to the suppression of recombination. We describe the genomic changes as the ancestral chromosome evolved into the current XY pair, testing ideas about the evolution of large nonrecombining regions and the mechanisms that created the present recombination pattern.
Sequence-dependent activity and compartmentalization of foreign DNA in a eukaryotic nucleus
Research Article | Epigenetics | 2025-02-07 03:00 EST
Léa Meneu, Christophe Chapard, Jacques Serizay†, Alex Westbrook, Etienne Routhier, Myriam Ruault, Manon Perrot, Alexandros Minakakis, Fabien Girard, Amaury Bignaud, Antoine Even, Géraldine Gourgues, Domenico Libri, Carole Lartigue, Aurèle Piazza, Agnès Thierry, Angela Taddei, Frédéric Beckouët, Julien Mozziconacci, Romain Koszul
In eukaryotes, DNA-associated protein complexes coevolve with genomic sequences to orchestrate chromatin folding. We investigate the relationship between DNA sequence and the spontaneous loading and activity of chromatin components in the absence of coevolution. Using bacterial genomes integrated into Saccharomyces cerevisiae, which diverged from yeast more than 2 billion years ago, we show that nucleosomes, cohesins, and associated transcriptional machinery can lead to the formation of two different chromatin archetypes, one transcribed and the other silent, independently of heterochromatin formation. These two archetypes also form on eukaryotic exogenous sequences, depend on sequence composition, and can be predicted using neural networks trained on the native genome. They do not mix in the nucleus, leading to a bipartite nuclear compartmentalization, reminiscent of the organization of vertebrate nuclei.
The essential genome of Plasmodium knowlesi reveals determinants of antimalarial susceptibility
Research Article | Malaria | 2025-02-07 03:00 EST
Brendan Elsworth, Sida Ye, Sheena Dass, Jacob A. Tennessen, Qudseen Sultana, Basil T. Thommen, Aditya S. Paul, Usheer Kanjee, Christof Grüring, Marcelo U. Ferreira, Marc-Jan Gubbels, Kourosh Zarringhalam, Manoj T. Duraisingh
Measures to combat the parasites that cause malaria have become compromised because of reliance on a small arsenal of drugs and emerging drug resistance. We conducted a transposon mutagenesis screen in the primate malaria parasite Plasmodium knowlesi, producing the most complete classification of gene essentiality in any Plasmodium spp. to date, with the resolution to define truncatable genes. We found conservation in the druggable genome between Plasmodium spp. and divergences in mitochondrial metabolism. Perturbation analyses with the frontline antimalarial artemisinin revealed modulators that both increase and decrease drug susceptibility. Our findings aid prioritization of drug and vaccine targets for the Plasmodium vivax clade and reveal mechanisms of resistance that can inform therapeutic development.
Whale song shows language-like statistical structure
Research Article | Animal communication | 2025-02-06 01:58 EST
Inbal Arnon, Simon Kirby, Jenny A. Allen, Claire Garrigue, Emma L. Carroll, Ellen C. Garland
Humpback whale song is a culturally transmitted behavior. Human language, which is also culturally transmitted, has statistically coherent parts whose frequency distribution follows a power law. These properties facilitate learning and may therefore arise because of their contribution to the faithful transmission of language over multiple cultural generations. If so, we would expect to find them in other culturally transmitted systems. In this study, we applied methods based on infant speech segmentation to 8 years of humpback recordings, uncovering in whale song the same statistical structure that is a hallmark of human language. This commonality, in two evolutionarily distant species, points to the role of learning and cultural transmission in the emergence of properties thought to be unique to human language.
Does the mantis shrimp pack a phononic shield?
Research Article | Biomaterials | 2025-02-06 01:58 EST
N. A. Alderete, S. Sandeep, S. Raetz, M. Asgari, M. Abi Ghanem, H. D. Espinosa
The powerful strikes generated by the smasher mantis shrimp require it to possess a robust protection mechanism to withstand the resultant forces. Although recent studies have suggested that phononic bandgaps complement the mantis shrimp's defensive suite, direct experimental evidence for this mechanism has remained elusive. In this work, we explored the phononic properties of the mantis shrimp's dactyl club using laser ultrasonic techniques and numerical simulations. Our results demonstrate that the dactyl club's periodic region functions as a dispersive, high-quality graded system, exhibiting Bloch harmonics, flat dispersion branches, ultraslow wave modes, and wide Bragg bandgaps in the lower megahertz range. These features effectively shield the shrimp from harmful high-frequency stress waves generated by cavitation bubble collapse events during impact.
Supersaturation mutagenesis reveals adaptive rewiring of essential genes among malaria parasites
Research Article | Malaria | 2025-02-07 03:00 EST
Jenna Oberstaller, Shulin Xu, Deboki Naskar, Min Zhang, Chengqi Wang, Justin Gibbons, Camilla Valente Pires, Matthew Mayho, Thomas D. Otto, Julian C. Rayner, John H. Adams
Malaria parasites are highly divergent from model eukaryotes. Large-scale genome engineering methods effective in model organisms are frequently inapplicable, and systematic studies of gene function are few. We generated more than 175,000 transposon insertions in the Plasmodium knowlesi genome, averaging an insertion every 138 base pairs, and used this "supersaturation" mutagenesis to score essentiality for 98% of genes. The density of mutations allowed mapping of putative essential domains within genes, providing a completely new level of genome annotation for any Plasmodium species. Although gene essentiality was largely conserved across P. knowlesi, Plasmodium falciparum, and rodent malaria model Plasmodium berghei, a large number of shared genes are differentially essential, revealing species-specific adaptations. Our results indicated that Plasmodium essential gene evolution was conditionally linked to adaptive rewiring of metabolic networks for different hosts.
Overwriting an instinct: Visual cortex instructs learning to suppress fear responses
Research Article | Neuroscience | 2025-02-06 01:58 EST
Sara Mederos, Patty Blakely, Nicole Vissers, Claudia Clopath, Sonja B. Hofer
Fast instinctive responses to environmental stimuli can be crucial for survival but are not always optimal. Animals can adapt their behavior and suppress instinctive reactions, but the neural pathways mediating such ethologically relevant forms of learning remain unclear. We found that posterolateral higher visual areas (plHVAs) are crucial for learning to suppress escapes from innate visual threats through a top-down pathway to the ventrolateral geniculate nucleus (vLGN). plHVAs are no longer necessary after learning; instead, the learned behavior relies on plasticity within vLGN populations that exert inhibitory control over escape responses. vLGN neurons receiving input from plHVAs enhance their responses to visual threat stimuli during learning through endocannabinoid-mediated long-term suppression of their inhibitory inputs. We thus reveal the detailed circuit, cellular, and synaptic mechanisms underlying experience-dependent suppression of fear responses.
Endothelial insulin resistance induced by adrenomedullin mediates obesity-associated diabetes
Research Article | Metabolism | 2025-02-06 01:58 EST
Haaglim Cho, Chien-Cheng Lai, Rémy Bonnavion, Mohamad Wessam Alnouri, ShengPeng Wang, Kenneth Anthony Roquid, Haruya Kawase, Diana Campos, Min Chen, Lee S. Weinstein, Alfredo Martínez, Mario Looso, Miloslav Sanda, Stefan Offermanns
Insulin resistance is a hallmark of obesity-associated type 2 diabetes. Insulin's actions go beyond metabolic cells and also involve blood vessels, where insulin increases capillary blood flow and delivery of insulin and nutrients. We show that adrenomedullin, whose plasma levels are increased in obese humans and mice, inhibited insulin signaling in human endothelial cells through protein-tyrosine phosphatase 1B-mediated dephosphorylation of the insulin receptor. In obese mice lacking the endothelial adrenomedullin receptor, insulin-induced endothelial nitric oxide-synthase activation and skeletal muscle perfusion were increased. Treating mice with adrenomedullin mimicked the effect of obesity and induced endothelial and systemic insulin resistance. Endothelial loss or blockade of the adrenomedullin receptor improved obesity-induced insulin resistance. These findings identify a mechanism underlying obesity-induced systemic insulin resistance and suggest approaches to treat obesity-associated type 2 diabetes.
Moisture-responsive root-branching pathways identified in diverse maize breeding germplasm
Research Article | Plant science | 2025-02-06 01:58 EST
Johannes D. Scharwies, Taylor Clarke, Zihao Zheng, Andrea Dinneny, Siri Birkeland, Margaretha A. Veltman, Craig J. Sturrock, Jason Banda, Héctor H. Torres-Martínez, Willian G. Viana, Ria Khare, Joseph Kieber, Bipin K. Pandey, Malcolm Bennett, Patrick S. Schnable, José R. Dinneny
Plants grow complex root systems to extract unevenly distributed resources from soils. Spatial differences in soil moisture are perceived by root tips, leading to the patterning of new root branches toward available water in a process called hydropatterning. Little is known about hydropatterning behavior and its genetic basis in crop plants. Here, we developed an assay to measure hydropatterning in maize and revealed substantial differences between tropical/subtropical and temperate maize breeding germplasm that likely resulted from divergent selection. Genetic analysis of hydropatterning confirmed the regulatory role of auxin and revealed that the gaseous hormone ethylene locally inhibits root branching from air-exposed tissues. Our results demonstrate how distinct signaling pathways translate spatial patterns of water availability to developmental programs that determine root architecture.
Four-dimensional conserved topological charge vectors in plasmonic quasicrystals
Research Article | Topological optics | 2025-02-06 01:58 EST
Shai Tsesses, Pascal Dreher, David Janoschka, Alexander Neuhaus, Kobi Cohen, Tim C. Meiler, Tomer Bucher, Shay Sapir, Bettina Frank, Timothy J. Davis, Frank Meyer zu Heringdorf, Harald Giessen, Guy Bartal
According to Noether's theorem, symmetries in a physical system are intertwined with conserved quantities. These symmetries often determine the system topology, which is made ever more complex with increased dimensionality. Quasicrystals have neither translational nor global rotational symmetry, yet they intrinsically inhabit a higher-dimensional space in which symmetry resurfaces. Here, we discovered topological charge vectors in four dimensions (4D) that govern the real-space topology of 2D quasicrystals and reveal their inherent conservation laws. We demonstrate control over the topology in pentagonal plasmonic quasilattices, mapped by both phase-resolved and time-domain near-field microscopy, showing that their temporal evolution continuously tunes the 2D projections of their distinct 4D topologies. Our work provides a route to experimentally probe the thermodynamic properties of quasicrystals and topological physics in 4D and above.
Kidney multiome-based genetic scorecard reveals convergent coding and regulatory variants
Research Article | Nephrology | 2025-02-07 03:00 EST
Penn Medicine BioBank Daniel J. Rader, Marylyn D. Ritchie, JoEllen Weaver, Nawar Naseer, Giorgio Sirugo, Afiya Poindexter, Yi-An Ko, Kyle P. Nerz, Meghan Livingstone, Fred Vadivieso, Stephanie DerOhannessian, Teo Tran, Julia Stephanowski, Salma Santos, Ned Haubein, Joseph Dunn, Anurag Verma, Colleen Morse Kripke, Marjorie Risman, Renae Judy, Colin Wollack, Shefali S. Verma, Scott M. Damrauer, Yuki Bradford, Scott M. Dudek, Theodore G. Drivas
Kidney dysfunction is a major cause of mortality, but its genetic architecture remains elusive. In this study, we conducted a multiancestry genome-wide association study in 2.2 million individuals and identified 1026 (97 previously unknown) independent loci. Ancestry-specific analysis indicated an attenuation of newly identified signals on common variants in European ancestry populations and the power of population diversity for further discoveries. We defined genotype effects on allele-specific gene expression and regulatory circuitries in more than 700 human kidneys and 237,000 cells. We found 1363 coding variants disrupting 782 genes, with 601 genes also targeted by regulatory variants and convergence in 161 genes. Integrating 32 types of genetic information, we present the "Kidney Disease Genetic Scorecard" for prioritizing potentially causal genes, cell types, and druggable targets for kidney disease.
Nutrient-driven histone code determines exhausted CD8+ T cell fates
Research Article | Immunometabolism | 2025-02-07 03:00 EST
Shixin Ma, Michael S. Dahabieh, Thomas H. Mann, Steven Zhao, Bryan McDonald, Won-Suk Song, H. Kay Chung, Yagmur Farsakoglu, Lizmarie Garcia-Rivera, Filipe Araujo Hoffmann, Shihao Xu, Victor Y. Du, Dan Chen, Jesse Furgiuele, Michael A. LaPorta, Emily Jacobs, Lisa M. DeCamp, Brandon M. Oswald, Ryan D. Sheldon, Abigail E. Ellis, Longwei Liu, Peixiang He, Yingxiao Wang, Cholsoon Jang, Russell G. Jones, Susan M. Kaech
Exhausted T cells (TEX) in cancer and chronic viral infections undergo metabolic and epigenetic remodeling, impairing their protective capabilities. However, the impact of nutrient metabolism on epigenetic modifications that control TEX differentiation remains unclear. We showed that TEX cells shifted from acetate to citrate metabolism by down-regulating acetyl-CoA synthetase 2 (ACSS2) while maintaining ATP-citrate lyase (ACLY) activity. This metabolic switch increased citrate-dependent histone acetylation, mediated by histone acetyltransferase KAT2A-ACLY interactions, at TEX signature genes while reducing acetate-dependent histone acetylation, dependent on p300-ACSS2 complexes, at effector and memory T cell genes. Nuclear ACSS2 overexpression or ACLY inhibition prevented TEX differentiation and enhanced tumor-specific T cell responses. These findings unveiled a nutrient-instructed histone code governing CD8+ T cell differentiation, with implications for metabolic- and epigenetic-based T cell therapies.
Physical Review Letters
Entanglement Detection Length of Multipartite Quantum States
Research article | Quantum correlations, foundations & formalism | 2025-02-06 05:00 EST
Fei Shi, Lin Chen, Giulio Chiribella, and Qi Zhao
Multipartite entanglement is a valuable resource for quantum technologies. However, detecting this resource can be challenging: for genuine multipartite entanglement, the detection may require global measurements that are hard to implement experimentally. Here we introduce the concept of entanglement detection length, defined as the minimum number of particles that have to be jointly measured in order to detect genuine multipartite entanglement. For symmetric states, we show that the entanglement detection length can be determined by testing separability of the marginal states. For general states, we provide an upper bound on the entanglement detection length based on semidefinite programming. We show that the entanglement detection length is generally smaller than the minimum observable length needed to uniquely determine a multipartite state, and we provide examples achieving the maximum gap between these two quantities.
Phys. Rev. Lett. 134, 050201 (2025)
Quantum correlations, foundations & formalism, Quantum entanglement
Magic Resource Can Enhance the Quantum Capacity of Channels
Quantum channels | 2025-02-06 05:00 EST
Kaifeng Bu and Arthur Jaffe
We investigate the role of magic resource in the quantum capacity of channels. We consider the quantum channel of the recently proposed discrete beam splitter with the fixed environmental state. We find that if the fixed environmental state is a stabilizer state, then the quantum capacity is zero. Moreover, we find that the quantum capacity is nonzero for some magic states, and the quantum capacity increases linearly with respect to the number of single-qudit magic states in the environment. We also bound the maximal quantum capacity of the discrete beam splitter in terms of the amount of magic resource in the environmental states. These results suggest that magic resource can increase the quantum capacity of channels; it sheds new insight into the role of stabilizer and magic states in quantum communication.
Phys. Rev. Lett. 134, 050202 (2025)
Quantum channels, Quantum information theory, Resource theories
Fock-Space Delocalization and the Emergence of the Porter-Thomas Distribution from Dual-Unitary Dynamics
Research article | Chaos | 2025-02-06 05:00 EST
Pieter W. Claeys and Giuseppe De Tomasi
The chaotic dynamics of quantum many-body systems are expected to quickly randomize any structured initial state, delocalizing it in the Fock space. In this Letter, we study the spreading of an initial product state in Hilbert space under dual-unitary dynamics, captured by the inverse participation ratios and the distribution of overlaps (bit-string probabilities). We consider the self-dual kicked Ising model, a minimal model of many-body quantum chaos that can be seen as either a periodically driven Floquet model or a dual-unitary quantum circuit. Both analytically and numerically, we show that the inverse participation ratios rapidly approach their ergodic values, corresponding to those of Haar random states, and establish the emergence of the Porter-Thomas distribution for the overlap distribution. Importantly, this convergence happens exponentially fast in time, with a timescale that is independent of system size. We inspect the effect of local perturbations that break dual unitarity and show a slowdown of the spreading in Fock space, indicating that dual-unitary circuits are maximally efficient at preparing random states. Our Letter establishes bridges between the dynamics of many-body systems and random matrix theory through the time evolution of structured initial states and finds natural applications in demonstrating a quantum advantage in random sampling and in benchmarking quantum devices.
Phys. Rev. Lett. 134, 050405 (2025)
Chaos, Eigenstate thermalization, Quantum chaos, Quantum circuits, Quantum information processing, Quantum statistical mechanics, Ergodic theory, Random matrix theory
Quantum Detailed Fluctuation Theorem in Curved Spacetimes: The Observer Dependent Nature of Entropy Production
Research article | Fluctuation theorems | 2025-02-06 05:00 EST
Marcos L. W. Basso, Jonas Maziero, and Lucas C. Céleri
The interplay between thermodynamics, general relativity, and quantum mechanics has long intrigued researchers. Recently, important advances have been obtained in thermodynamics, mainly regarding its application to the quantum domain through fluctuation theorems. In this Letter, we apply Fermi normal coordinates to report a fully general relativistic detailed quantum fluctuation theorem based on the two point measurement scheme. We demonstrate how the spacetime curvature can produce entropy in a localized quantum system moving in a general spacetime. The example of a quantum harmonic oscillator living in an expanding universe is presented. This result implies that entropy production is strongly observer dependent and deeply connects the arrow of time with the causal structure of the spacetime.
Phys. Rev. Lett. 134, 050406 (2025)
Fluctuation theorems, General relativity, Quantum statistical mechanics, Stochastic processes
Accelerating Dissipative State Preparation with Adaptive Open Quantum Dynamics
Research article | Open quantum systems & decoherence | 2025-02-06 05:00 EST
Andrew Pocklington and Aashish A. Clerk
A wide variety of dissipative state preparation schemes suffer from a basic time-entanglement tradeoff: the more entangled the steady state, the slower the relaxation to the steady state. Here, we show how a minimal kind of adaptive dynamics can be used to completely circumvent this tradeoff, and allow the dissipative stabilization of maximally entangled states with a finite timescale. Our approach takes inspiration from simple fermionic stabilization schemes, which surprisingly are immune to entanglement-induced slowdown. We describe schemes for accelerated stabilization of many-body entangled qubit states (including spin squeezed states), both in the form of discretized Floquet circuits, as well as continuous time dissipative dynamics. Our ideas are compatible with a number of experimental platforms.
Phys. Rev. Lett. 134, 050603 (2025)
Open quantum systems & decoherence, Quantum circuits, Quantum entanglement, Lindblad equation
Boosting Supermassive Black Hole Growth in the Early Universe by Fuzzy Dark Matter Solitons
Research article | Dark matter | 2025-02-06 05:00 EST
H.-H. Sandy Chiu (邱懷萱), Hsi-Yu Schive (薛熙于), Hsiang-Yi Karen Yang (楊湘怡), Hsinhao Huang (黃新豪), and Massimo Gaspari
Observations of massive supermassive black holes (SMBHs) in the early Universe challenge existing black hole formation models. We propose that soliton cores in fuzzy dark matter (FDM) offer a potential solution to this timing problem. Our FDM cosmological zoom-in simulations confirm that, for a particle mass \({m}_{\mathrm{FDM}}\sim {10}^{- 22}\text{ }\text{ }\mathrm{eV}\), solitons are well developed at redshift \(z\sim 7\) with masses of \(\sim {10}^{9}{M}_{\bigodot }\), comparable to the observed SMBHs. We then demonstrate using hydrodynamic simulations that, compared to cold dark matter, these high-\(z\) massive FDM solitons with mass \({M}_{s}\) can provide additional gravitational potential to accrete gas and boost the Bondi accretion rate of a growing black hole seed with mass \({M}_{\mathrm{BH}}\) by up to 2--4 orders of magnitude, in the regime of efficient cooling and negligible radiation pressure. This accretion boosting mechanism is effective for \({10}^{- 22}\lesssim {m}_{\mathrm{FDM}}\lesssim {10}^{- 20}\text{ }\text{ }\mathrm{eV}\) and potentially beyond as long as \({M}_{s}>{M}_{\mathrm{BH}}\).
Phys. Rev. Lett. 134, 051402 (2025)
Dark matter, Primordial black holes
Monopole-Fermion Scattering and the Solution to the Semiton--Unitarity Puzzle
Quantum field theory | 2025-02-06 05:00 EST
Vazha Loladze and Takemichi Okui
The scattering of a charged particle off a magnetic monopole does not imply the existence of fractional particle numbers, theorists say.
Phys. Rev. Lett. 134, 051602 (2025)
Quantum field theory, Hypothetical particles, Magnetic monopoles
Many-Body Adiabatic Passage: Instability, Chaos, and Quantum Classical Correspondence
Research article | Cold atoms & matter waves | 2025-02-06 05:00 EST
Anant Vijay Varma, Amichay Vardi, and Doron Cohen
Adiabatic passage in systems of interacting bosons is substantially affected by interactions and interparticle entanglement. We consider stimulated raman-adiabatic-passage-like schemes in Bose-Hubbard chains that exhibit low-dimensional chaos (a three-site chain) and high-dimensional chaos (more than three sites). The dynamics that is generated by a transfer protocol exhibits striking classical and quantum chaos fingerprints that are manifested in the mean-field classical treatment, in the truncated Wigner semiclassical treatment, and in the full many-body quantum simulations.
Phys. Rev. Lett. 134, 053201 (2025)
Cold atoms & matter waves, Quantum chaos, Stimulated Raman adiabatic passage, Bose-Einstein condensates
Optical Superlattice for Engineering Hubbard Couplings in Quantum Simulation
Research article | Cold gases in optical lattices | 2025-02-06 05:00 EST
Thomas Chalopin, Petar Bojović, Dominik Bourgund, Si Wang, Titus Franz, Immanuel Bloch, and Timon Hilker
Quantum simulations of Hubbard models with ultracold atoms rely on the exceptional control of coherent motion provided by optical lattices. Here we demonstrate enhanced tunability using an optical superlattice in a fermionic quantum gas microscope, evidenced by long-lived coherent double-well oscillations, next-nearest-neighbor quantum walks in a staggered configuration, and correlated quantum walks of two particles initiated through a resonant pair-breaking mechanism. We furthermore demonstrate tunable spin couplings through local offsets and engineer a spin ladder with ferromagnetic and antiferromagnetic couplings along the rungs and legs, respectively. Our Letter underscores the high potential of optical superlattices for engineering, simulating, and detecting strongly correlated many-body quantum states, with direct applications ranging from the study of mixed-dimensional systems to fermionic quantum computing.
Phys. Rev. Lett. 134, 053402 (2025)
Cold gases in optical lattices, Optical lattices & traps, Quantum simulation, Quantum walks, Hubbard model
Autonomous Feedback Stabilization of a Cavity-Coupled Spin Oscillator
Research article | Atoms, ions, & molecules in cavities | 2025-02-06 05:00 EST
Julian Wolf, Olive H. Eilbott, Joshua A. Isaacs, Kevin P. Mours, Jonathan Kohler, and Dan M. Stamper-Kurn
We report out-of-equilibrium stabilization of the collective spin of an atomic ensemble through autonomous feedback by a driven optical cavity. For a magnetic field applied at an angle to the cavity axis, dispersive coupling to the cavity provides sensitivity to a combination of the longitudinal and transverse spin. Coherent backaction by cavity light onto the atoms, conditioned by the cavity susceptibility, stabilizes the spin state at an arbitrary energy. The setpoint tracking and closed-loop gain spectrum of the feedback system are characterized and found to agree closely with analytic predictions.
Phys. Rev. Lett. 134, 053603 (2025)
Atoms, ions, & molecules in cavities, Cavity quantum electrodynamics, Coherent control, Quantum feedback, Atomic ensemble, Quantum cavities, Trapped atoms, Ultracold gases, Homodyne & heterodyne detection
Suppression of Motional Dephasing Using State Mapping
Research article | Coherent control | 2025-02-06 05:00 EST
Yuechun Jiao, Changcheng Li, Xiao-Feng Shi, Jiabei Fan, Jingxu Bai, Suotang Jia, Jianming Zhao, and C. Stuart Adams
Rydberg-mediated quantum optics is a useful route toward deterministic quantum information processing based on single photons and quantum networks but is bottlenecked by the fast motional dephasing of Rydberg atoms. Here, we propose and experimentally demonstrate suppressing the motional dephasing by creating an a priori unknown but correct phase to each Rydberg atom in an atomic ensemble. The phase created is exactly proportional to the unknown velocity of the thermal motion, resulting in a condition as if no thermal motion occurs to the Rydberg atom upon the retrieval of the signal photon. Our experiments, though hampered by the noise of lasers and the environment, demonstrate more than one order of magnitude enhancement of the coherence time. The feasibility of realizing long-lived storage of single photons in strongly interacting Rydberg media sheds new light on Rydberg-mediated quantum nonlinear optics.
Phys. Rev. Lett. 134, 053604 (2025)
Coherent control, Collective effects in quantum optics, Rydberg gases
Postselection-Free Cavity-Enhanced Narrow-Band Orbital Angular Momentum Entangled Photon Source
Research article | Quantum communication | 2025-02-06 05:00 EST
Pei Wan (万佩), Wen-Zheng Zhu (朱文正), Yan-Chao Lou (娄严超), Zi-Mo Cheng (程子默), Zhi-Cheng Ren (任志成), Han Zhang (张涵), Xi-Lin Wang (汪喜林), and Hui-Tian Wang (王慧田)
Cavity-enhanced spontaneous parametric down-conversion (SPDC) provides a significant way to produce \(\sim 10\text{ }\text{ }\mathrm{MHz}\) narrow-band photon pairs, which matches the bandwidth of photon for quantum memory. However, the output photon pairs from the cavity are not entangled, and postselection is required to create the entanglement so far, so the direct output of cavity-enhanced narrow-band entangled photon pairs is still an open challenge. Here, we propose a solution that realizes the first postselection-free cavity-enhanced narrow-band entangled photon pairs. The entanglement is achieved in degree of freedom of orbital angular momentum (OAM) by an OAM-conservation SPDC process in an actively and precisely controlled cavity supporting degenerate high-order OAM modes. The measured linewidth and fidelity are 13.8 MHz and 0.969(3), respectively, for the directly generated OAM entangled two photons. We deterministically transfer the OAM entanglement to polarization one with almost no loss and obtain polarization entangled two photons with a fidelity of 0.948(2). Moreover, we produce narrow-band OAM-polarization hyperentangled photon pairs with a fidelity of 0.850(2), which is realized by interfering the two photons on a polarizing beam splitter (PBS) and postselecting the events of one and only one photon on each PBS port. Novel cavity may find applications in cavity-based light-matter interaction. Our results provide an efficient and promising approach to create narrow-band entangled photon sources for memory-based long-distance quantum communication and network.
Phys. Rev. Lett. 134, 053801 (2025)
Quantum communication, Quantum control
Bounds on Heavy Axions with an X-Ray Free Electron Laser
Research article | Axion-like particles | 2025-02-06 05:00 EST
Jack W. D. Halliday, Giacomo Marocco, Konstantin A. Beyer, Charles Heaton, Motoaki Nakatsutsumi, Thomas R. Preston, Charles D. Arrowsmith, Carsten Baehtz, Sebastian Goede, Oliver Humphries, Alejandro Laso Garcia, Richard Plackett, Pontus Svensson, Georgios Vacalis, Justin Wark, Daniel Wood, Ulf Zastrau, Robert Bingham, Ian Shipsey, Subir Sarkar, and Gianluca Gregori
We present new exclusion bounds obtained at the European X-Ray Free Electron Laser facility (EuXFEL) on axionlike particles in the mass range \({10}^{- 3}\text{ }\text{ }\mathrm{eV}\lesssim {m}_{a}\lesssim {10}^{4}\text{ }\text{ }\mathrm{eV}\). Our experiment exploits the Primakoff effect via which photons can, in the presence of a strong external electric field, decay into axions, which then convert back into photons after passing through an opaque wall. While similar searches have been performed previously at a third-generation synchrotron [Yamaji et al., Phys. Lett. B 782, 523 (2018)], our work demonstrates improved sensitivity, exploiting the higher brightness of x-rays at EuXFEL.
Phys. Rev. Lett. 134, 055001 (2025)
Axion-like particles, Axions, Free-electron lasers, Dynamical diffraction
Laboratory Demonstration of Collisionless Blob Formation via Laser-Produced Plasma Self-Focusing
Research article | High-energy-density plasmas | 2025-02-06 05:00 EST
R. S. Dorst, A. Le, C. G. Constantin, D. J. Larson, J. J. Pilgram, S. Vincena, S. K. P. Tripathi, M. M. Cowee, D. Winske, D. B. Schaeffer, and C. Niemann
Strongly localized, propagating plasma density structures that are capable of crossing magnetic field lines are known as ''blobs.'' Here we demonstrate a novel mechanism for the formation and propagation of an ion gyroradius-scale blob-cavity structure at the interface between a super-Alfv'enic laser-produced plasma (LPP) and an ambient magnetized plasma. The LPP self-focuses along the edge of the diamagnetic cavity which results in a dense, jetlike structure as compared to ballistic motion. This collimated flow couples momentum to the ambient plasma through a collisionless process known as Larmor coupling. The Larmor electric fields locally displace the ambient ions forming a blob above the LPP flow. In the region between a gyrating blob and collimated LPP flow, a secondary cavity of expelled magnetic field forms. These findings are supported by particle-in-cell simulations that replicate the blob formation mechanism and provide insight to similar processes in space, astrophysical, and laboratory settings characterized by ion kinetic scales.
Phys. Rev. Lett. 134, 055101 (2025)
High-energy-density plasmas, Laboratory studies of space & astrophysical plasmas, Magnetized plasma, Fluorescence spectroscopy, Imaging & optical processing, Laser ablation, Laser techniques, Optical plasma measurements, Optical pumping, Particle-in-cell methods
Hall Response in Interacting Bosonic and Fermionic Ladders
Research article | Hall effect | 2025-02-06 05:00 EST
R. Citro, T. Giamarchi, and E. Orignac
We use bosonization, retaining band curvature terms, to analyze the Hall response of interacting bosonic and fermionic two-leg ladders threaded by a flux. We derive an explicit expression of the Hall imbalance in a perturbative expansion in the band curvature, retaining fully the interactions. We show that the flux dependence of the Hall imbalance allows to distinguish the two phases (Meissner and vortex) that are present for a bosonic ladder. For small magnetic field we relate the Hall resistance, both for bosonic and fermionic ladders, to the density dependence of the charge stiffness of the system in absence of flux. Our expression unveils a universal interaction-independent behavior in the Galilean invariant case.
Phys. Rev. Lett. 134, 056501 (2025)
Hall effect, Synthetic gauge fields, Josephson junctions, Nanoribbon, Sine-Gordon equation, Ultracold gases, Bosonization, Luttinger liquid model
Transient Dynamical Phase Diagram of the Spin-Boson Model
Research article | Dissipative dynamics | 2025-02-06 05:00 EST
Olga Goulko, Hsing-Ta Chen, Moshe Goldstein, and Guy Cohen
We investigate the real-time dynamics of the sub-Ohmic spin-boson model across a broad range of coupling strengths, using the numerically exact inchworm quantum Monte Carlo algorithm. From short- and intermediate-time dynamics starting from an initially decoupled state, we extract signatures of the zero-temperature quantum phase transition between localized and delocalized states. We show that the dynamical phase diagram thus obtained differs from the equilibrium phase diagram in both the values of critical couplings and the associated values of the critical exponent. We also identify and quantitatively analyze two competing mechanisms for the crossover between coherent oscillations and incoherent decay. Deep in the sub-Ohmic regime, the crossover is driven by the damping of the oscillation amplitude, while closer to the Ohmic regime the oscillation frequency itself drops sharply to zero at large coupling.
Phys. Rev. Lett. 134, 056502 (2025)
Dissipative dynamics, Quantum phase transitions, Strongly correlated systems, Quantum Monte Carlo, Spin-boson model
Observation of Coherent Gapless Magnons in an Antiferromagnet
Research article | Domain walls | 2025-02-06 05:00 EST
Jilei Chen, Zhejunyu Jin, Rundong Yuan, Hanchen Wang, Hao Jia, Weiwei Wei, Lutong Sheng, Jinlong Wang, Yuelin Zhang, Song Liu, Dapeng Yu, Jean-Philippe Ansermet, Peng Yan, and Haiming Yu
Antiferromagnetic magnons possess high speed and are immune to external disturbance, making them promising for future magnonic circuits. In this Letter, we report the observation of gapless magnons in an easy-axis antiferromagnet \(\alpha \text{- }{\mathrm{Fe}}_{2}{\mathrm{O}}_{3}\) at low temperatures. These antiferromagnetic magnons are detected at nearly zero frequency by all-electrical spin-wave spectroscopy and propagate along antiferromagnetic domain walls as revealed by our theoretical model and simulations. Moreover, we demonstrate high coherency of these gapless magnons by showing their strong coupling with microwave photons. Our results open the pathway for antiferromagnetic texture based magnonic devices operating at microwave frequencies.
Phys. Rev. Lett. 134, 056701 (2025)
Domain walls, Magnons, Spintronics, Antiferromagnets, Microwave techniques
Direct and Retrograde Wave Propagation in Unidirectionally Coupled Wilson-Cowan Oscillators
Research article | Bifurcations | 2025-02-06 05:00 EST
Guy Elisha, Richard Gast, Sourav Halder, Sara A. Solla, Peter J. Kahrilas, John E. Pandolfino, and Neelesh A. Patankar
Some biological systems exhibit both direct and retrograde propagating signal waves despite unidirectional coupling. To explain this phenomenon, we study a chain of unidirectionally coupled Wilson-Cowan oscillators. Surprisingly, we find that changes in the homogeneous global input to the chain suffice to reverse the wave propagation direction. To obtain insights, we analyze the frequencies and bifurcations of the limit cycle solutions of the chain as a function of the global input. Specifically, we determine that the directionality of wave propagation is controlled by differences in the intrinsic frequencies of oscillators caused by the differential proximity of the oscillators to a homoclinic bifurcation.
Phys. Rev. Lett. 134, 058401 (2025)
Bifurcations, Coupled oscillators, Dynamics of networks, Synchronization, Synchronization transition, Neuronal network models
Physical Review X
Quantum Spin Ice in Three-Dimensional Rydberg Atom Arrays
Research article | Fractionalization | 2025-02-06 05:00 EST
Jeet Shah, Gautam Nambiar, Alexey V. Gorshkov, and Victor Galitski
A novel proposal for realizing a type of quantum spin liquid uses 3D Rydberg atom arrays, paving the way to probe a phase of matter that has largely eluded physicists for decades.
Phys. Rev. X 15, 011025 (2025)
Fractionalization, Lattice gauge theory, Quantum simulation, Quantum spin liquid, Rydberg atoms & molecules
arXiv
On the Convergence of Strong Cylindrical and Spherical Shock Waves in Solid Materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-06 20:00 EST
In this article, we present a description of the behaviour of shock-compressed solid materials following the Geometrical Shock Dynamics (GSD) theory. GSD has been successfully applied to various gas dynamics problems, and here we have employed it to investigate the propagation of cylindrically and spherically symmetric converging shock waves in solid materials. The analytical solution of shock dynamics equations has been obtained in strong-shock limit, assuming the solid material to be homogeneous and isotropic and obeying the Mie-Gruneisen equation of state. The non-dimensional expressions are obtained for the velocity of shock, the pressure, the mass density, the particle velocity, the temperature, the speed of sound, the adiabatic bulk modulus, and the change-in-entropy behind the strong converging shock front. The influences as a result of changes in (i) the propagation distance r from the axis or centre (r=0) of convergence, (ii) the Gruneisen parameter, and (iii) the material parameter are explored on the shock velocity and the domain behind the converging shock front. The results show that as the shock focuses at the axis or origin, the shock velocity, the pressure, the temperature, and the change-in-entropy increase in the shock-compressed titanium Ti6Al4V, stainless steel 304, aluminum 6061-T6, etc.
Materials Science (cond-mat.mtrl-sci), High Energy Astrophysical Phenomena (astro-ph.HE), Applied Physics (physics.app-ph)
14pages, 2figures
Proc. Natl. Acad. Sci., India, Sect. A Phys. Sci. (2025)
The study of the energy spectrum of a system of quantum micro-vortices in a bounded spatial domain
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-02-06 20:00 EST
This study focuses on microscopic-sized quantum vortex filaments that are shaped like a circle. The model we considered examines loops with different radii and a small but non-zero core diameter. These loops are located in a bounded domain \(D\). The quantization scheme of the classical vortices is based on the new approach proposed by the author . For these loops, we calculate both the quantized circulation and the energy spectrum, which are perfectly non-trivial. To understand how the results we have obtained can be used to describe the initial stage of turbulence in a quantum fluid, we study a system of \(K\) random, non-interacting vortices. We explain how specific energy and circulation spectra lead to the occurrence of turbulence in the context of the developed approach.
Quantum Gases (cond-mat.quant-gas), Mathematical Physics (math-ph)
21 pages 2 figures
Dynamics and lifetime of geometric excitations in moir'e systems
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-06 20:00 EST
Yuzhu Wang, Joe Huxford, Dung Xuan Nguyen, Guangyue Ji, Yong Baek Kim, Bo Yang
We show that spin-2 geometric excitations, known as graviton modes, generally exhibit vanishing lifetimes in lattice Chern bands, including in moiré systems. In contrast to the Landau levels, we first numerically demonstrate that the prominent graviton peaks in spectral functions diminish rapidly with increasing system sizes. We explore how the choice of interaction affects the strength of these peaks, with short-ranged interactions pushing the graviton mode far into the continuum of excitations, where it can be significantly scattered due to the increased density of states. We also analytically investigate the short lifetime of the graviton mode. In lattice systems, continuous rotational symmetry is broken, leading to highly anisotropic gapped excitations that mix different angular momentum or "spins''. This is despite the surprising emergence of a "guiding center" continuous rotational symmetry in the ground state, which is shared by the graviton mode. Consequently, the graviton mode in Chern bands can be strongly scattered by the anisotropic gapped excitations. However, the emergent rotational symmetry implies that gravitons can be robust in principle, and we propose experimental tuning strategies to lower the graviton mode energy below the continuum. We argue this is a necessary condition enabling the observation of graviton modes and geometric excitations in realistic moiré systems.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
9 pages, 4 figures, comments very welcome
Monitored interacting Dirac fermions
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-02-06 20:00 EST
Thomas Martin Müller, Michael Buchhold, Sebastian Diehl
We analytically study interacting Dirac fermions, described by the Thirring model, under weak local particle number measurements with monitoring rate \(\gamma\). This system maps to a bosonic replica field theory, analyzed via the renormalization group. For a nonzero attractive interaction, a phase transition occurs at a critical measurement strength \(\gamma_c\). When \(\gamma>\gamma_c\), the system enters a localized phase characterized by exponentially decaying density-density correlations beyond a finite correlation length; for \(\gamma<\gamma_c\), the correlations decay algebraically. The transition is of BKT-type, reflected by a characteristic scaling of the correlation length. In the non-interacting limit, \(\gamma_c\to0\) shifts to zero, reducing the algebraic phase to a single point in parameter space. This identifies weak measurements in the free case as an implicit double fine-tuning to the critical endpoint of the BKT phase transition. Along the non-interacting line, we compute the entanglement entropy from density-density correlation functions and find no entanglement transition at nonzero measurement strength in the thermodynamic limit.
Statistical Mechanics (cond-mat.stat-mech), Disordered Systems and Neural Networks (cond-mat.dis-nn), Quantum Physics (quant-ph)
Spectral form factor and energy correlations in banded random matrices
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-02-06 20:00 EST
Adway Kumar Das, Anandamohan Ghosh, Lea F. Santos
Banded random matrices were introduced as a more realistic alternative to full random matrices for describing the spectral statistics of heavy nuclei. Initially considered by Wigner, they have since become a paradigmatic model for investigating level statistics and the localization-delocalization transition in disordered quantum systems. In this work, we demonstrate that, despite the absence of short-range energy correlations, weak long-range energy correlations persist in the nonergodic phase of banded random matrices. This result is supported by our numerical and analytical studies of quantities that probe both short- and long-range energy correlations, namely, the spectral form factor, level number variance, and power spectrum. We derive the timescales for the onset of spectral correlations (ramp) and for the saturation (plateau) of the spectral form factor. Unexpectedly, we find that in the nonergodic phase, these timescales decrease as the bandwidth of the matrices is reduced. We also show that the high-frequency behavior of the power spectrum of energy fluctuations can distinguish between the nonergodic and ergodic phases of the banded random matrices.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Quantum Physics (quant-ph)
14 pages, 7 figures
Phase space fractons
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-02-06 20:00 EST
Ylias Sadki, Abhishodh Prakash, S. L. Sondhi, Daniel P. Arovas
Perhaps the simplest approach to constructing models with sub-dimensional particles or fractons is to require the conservation of dipole or higher multipole moments. We generalize this approach to allow for moments in phase space and classify all possible classical fracton models with phase-space multipole conservation laws. We focus on a new self-dual model that conserves both dipole and quadrupole moments in position and momentum; we analyze its dynamics and find quasi-periodic orbits in phase space that evade ergodic exploration of the full phase space.
Statistical Mechanics (cond-mat.stat-mech), Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Phenomenology (hep-ph), Classical Physics (physics.class-ph)
5 pages, 1 figure
Enhancing the hyperpolarizability of crystals with quantum geometry
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-06 20:00 EST
Wojciech J. Jankowski, Robert-Jan Slager, Michele Pizzochero
We demonstrate that higher-order electric susceptibilities in crystals can be enhanced and understood through nontrivial topological invariants and quantum geometry, using one-dimensional \(\pi\)-conjugated chains as representative model systems. First, we show that the crystalline-symmetry-protected topology of these chains imposes a lower bound on their quantum metric and hyperpolarizabilities. Second, we employ numerical simulations to reveal the tunability of non-linear, quantum geometry-driven optical responses in various one-dimensional crystals in which band topology can be externally controlled. Third, we develop a semiclassical picture to deliver an intuitive understanding of these effects. Our findings offer a firm interpretation of otherwise elusive experimental observations of colossal hyperpolarizabilities and establish guidelines for designing topological materials of any dimensionality with enhanced non-linear optical properties.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Optics (physics.optics), Quantum Physics (quant-ph)
5+12 pages, 3+1 figures
Enhanced Cooper pairing in nano-patterned metals
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-06 20:00 EST
Masoud Mohammadi-Arzanagh, Andrey Grankin, Victor Galitski, Mohammad Hafezi
Nano-patterning has been shown to be a powerful tool for manipulating the vibrational modes of elastic structures, with applications such as optical-mechanical mode coupling. Inspired by these recent developments in phononic band engineering, we propose a nano-patterning scheme to enhance the superconducting transition temperature \(T_c\) in phonon-mediated nano-film superconductors, such as aluminum. Using the finite element method, we simulate the lattice vibrational modes of nano-patterned films within the Debye model. Our results show that periodic nano-patterning softens the lattice vibrational modes compared to bulk films. It also increases the density of states at high energies, resulting in a couple of percent enhancement in \(T_c\). Moreover, we investigate connections to random matrix theory and provide an experimental design prescription to optimize nano-patterning for further enhancement of the superconducting transition temperature.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
7 pages, 4 figures
Dispersion of neutral collective modes in partonic fractional quantum Hall states and its applications to paired states of composite fermions
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-06 20:00 EST
The Moore-Read Pfaffian (Pf) state exhibits two distinct neutral excitation modes, the bosonic magnetoroton mode, and the neutral fermion mode. These two modes have been conjectured to be supersymmetric (SUSY) partners in the long-wavelength limit. Previous studies on these neutral excitations of the Pf state have shown evidence in favor of SUSY in the vicinity of the second Landau level (SLL) Coulomb interaction. Inspired by that, using the framework of parton theory, we test the SUSY conjecture for a state that lies in the same universality class as the particle-hole conjugate of the Pf, namely the anti-Pf (aPf) state, by constructing explicit wave functions for its magnetoroton and neutral fermion excitations and evaluating them for very large system sizes. As with the previous studies on the Pf state, we find that the long-wavelength gaps of the neutral modes of the parton state belonging to the same topological class as the aPf are close to each other for the SLL Coulomb interaction. Furthermore, using the parton wave functions, we compute the dispersion of various neutral collective excitations, including the magnetoroton, neutral fermion, and parton-excitons, for several notable non-Abelian and Abelian states. Finally, we propose a parton-exciton ansatz for the gapped neutral excitation of the composite fermion Fermi liquid at quarter filling and compute its dispersion for the Coulomb interaction in the lowest Landau level.
Strongly Correlated Electrons (cond-mat.str-el)
Effects of rotation on the thermodynamic properties of a quantum dot
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-06 20:00 EST
Luís Fernando C. Pereira, Edilberto O. Silva
In this work, we investigate the effects of rotation on the physical properties of a quantum dot described by a radial potential and subjected to a rotating reference frame. The interplay between rotation and confinement is analyzed by solving the Schrödinger equation for the system, yielding energy levels and wavefunctions as functions of angular velocity. We compute key thermodynamic properties, including the density of states, magnetization, entropy, and heat capacity, in the absence of an external magnetic field. Our results demonstrate that rotation induces significant modifications to the energy spectrum, removing degeneracies and generating oscillatory behaviors in magnetization akin to de Haas-van Alphen and Aharonov-Bohm-type oscillations. Furthermore, we observe an effect analogous to the magnetocaloric effect, where an increase in angular velocity leads to a decrease in temperature during adiabatic processes. These results reveal the potential of rotational effects to influence quantum systems and provide insights for future studies in mesoscopic physics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
6 pages, 5 figures
Critical Current, Lengthwise Fluctuations, and Flux Jumps in REBCO CC: A Torque Magnetometry Study up to 45 T
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-06 20:00 EST
J. Jaroszynski, A-M Constantinescu, D. Kolb-Bond, A. Francis, A. Xu, R. Ries, G. Bradford, J. Bang, J. Lee, D. Larbalestier (National High Magnetic Field Laboratory, Tallahassee FL)
REBCO (Rare Earth Barium Copper Oxide) coated conductors (CCs) have emerged for future high field magnets in fields and temperatures inaccesible for Nb based superconductors. However, their exceptionally high current densities pose challenges for characterization at low temperatures. This paper presents the design and implementation of a simple torque magnetometer especially suitable for characterizing REBCO CC. It details the construction and underlying physics, with particular emphasis on its capability to assess angular critical currents Ic in high magnetic fields and low temperatures. The study includes characterizations of multiple REBCO samples from different manufacturers, performed under magnetic fields up to 45 T, demonstrating the exceptional capabilities of REBCO CCs in extreme fields. The results reveal significant lengthwise Ic variations, especially in tapes cut from the edges of 12 mm-wide production tapes compared to those cut from the center. These variations are most pronounced when the field is in the vicinity of the ab-plane. Importantly, flux jumps are observed in samples with thick REBCO layers and thin stabilizers, underscoring potential thermal instabilities. These findings provide valuable insights into REBCO tape performance under extreme magnetic fields, highlighting their relevance for high-field magnet and nuclear fusion applications.
Superconductivity (cond-mat.supr-con)
22 pages, 10 figures
High performance vacuum annealed beta-(AlxGa1-x)2O3/Ga2O3 HFET with f_T/f_MAX of 32/65 GHz
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-06 20:00 EST
Chinmoy Nath Saha, Noor Jahan Nipu, Uttam Singisetti
This letter reports high performance beta-(AlxGa1-x)2O3/Ga2O3 Heterostructure FET (HFET) with improved regrowth process. Highly scaled I shaped gate have been fabricated with degenerately doped (N++) source/drain contact regrown by ozone molecular beam epitaxy (MBE). Aiming to address the limitations observed in previous generation devices, this work incorporates a low-power BCl3/Ar and SF6/Ar plasma etching process to remove the AlGaO barrier layer and Ga2O3 layer respectively before regrowth. Additionally, the surface was cleaned and vacuum annealing was carried out before MBE regrowth to reduce any interface resistance between highly doped regrowth N++ and 2DEG layer. These meticulously designed fabrication steps enabled us to achieve the high DC current 0.5 A/mm at 5V drain bias with 6.1 \(\mathrm{\Omega}\).mm on resistance (R) at V_GS=3V, peak transconductance (g_m) of 110 mS/mm at room temperature (V_DS=15V) and around 0.8 A/mm (V_DS=5V) peak I_ON} at low temperature (100K). Current gain cut-off frequency (f_T) of 32 GHz and peak power gain cut-off frequency (f_MAX) of 65 GHz were extracted from RF measurements. f_T.L_G product was estimated to be 6.1 GHz-\(\mu\)m for 191 nm L_G and 32 GHz f_T, which is one of the highest reported among Ga2O3 devices. With thicker Al2O3, device shows no current collapse demonstrating first time successful traps passivation with Al2O3 for Ga2O3 devices.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph)
Pore network models for the evaporation of complex fluids in porous media
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-06 20:00 EST
Romane Le Dizès Castell, Marc Prat, Noushine Shahidzadeh, Sara Jabbari-Farouji
Drying of fluids undergoing sol-gel transition in porous media, a process crucial for the consolidation of damaged porous structures in cultural heritage, often leads to skin formation at the surface. This phenomenon significantly hinders evaporation, yet its precise impact on drying kinetics remains poorly understood. To uncover the governing mechanisms, we develop a novel pore network model that closely replicates quasi-2D experimental porous media, incorporating spatial gradients in pore size distribution, with smaller pores near the evaporation side. We demonstrate that this pore distribution dictates the air invasion path and extends the constant-rate period of drying in Newtonian liquids, reproducing the experimental drying curves for water. We further extend our model to capture the interplay of capillary-driven liquid flows, space-dependent viscosity increases, and localized skin formation. To incorporate skin formation, we implement a viscosity-dependent evaporation pressure rule derived from experimental data on evaporation-induced sol-gel transition within a capillary tube. We identify a simple relationship: vapor pressure decreases once the meniscus fluid viscosity exceeds a critical threshold. By accounting for localized skin formation through reduced evaporation pressure at high-viscosity throats, our model successfully captures the slowdown of drying kinetics, achieving remarkable agreement with experimental drying curve.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
15 pages, 14 figures including the appendix
Variational Scarring in Open Two-Dimensional Quantum Dots
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-06 20:00 EST
Fartash Chalangari, Joonas Keski-Rahkonen, Simo Selinummi, Esa Räsänen
Quantum scars have recently been directly visualized in graphene quantum dots (Nature 635, 841 (2024)), revealing their resilience and influence on electron dynamics in mesoscopic systems. Here, we examine variational scarring in two-dimensional quantum dots and demonstrate that these states remain robust even in an open system. We show that controlled perturbations enable modulation of electronic transmission via scarred states, presenting a viable approach to tuning quantum transport. These findings provide insights into the role of scarring in mesoscopic transport and open pathways for experimental realization in quantum devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
Electronic origin of stability of 2D 1H-phase Janus transition metal dichalcogenides and beyond
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-06 20:00 EST
Lei Li, Ji-Chun Lian, Zi-Xuan Yang, Tao Huang, Jun-Qi Xu, Jianhang Nie, Hui Wan, X. S. Wang, Gui-Fang Huang, Wangyu Hu, Wei-Qing Huang
Janus transition metal dichalcogenides (JTMDs) monolayers have emerged as a new paradigm to broaden the family of two-dimensional (2D) materials. Despite numerous theoretical predictions of JTMDs, their experimental realization remains scarce, most probably due to intrinsic structural fragility. We identify a dependence of the structural stability of 1H-phase JTMDs on the transition metal group, with Group-VIB-based monolayers exhibiting robust stability, as evidenced by the successful synthesized MoSSe and WSSe. The group-dependent stability arises from the competition between metal-ligand ionic bonding and ligand-ligand covalent bonding, as well as the high-energy d-electron orbital splitting. We propose an electron configuration that describes the interactions of electrons near the Fermi level to correlate the stability, and introduce an electron compensation strategy to stabilize certain unstable JTMDs systems. Guided by the electronic origin of stability, we predict a family of stable 2D Janus transition metal halides with intrinsic ferromagnetic valley properties. This work bridges the gap between electronic structure and stability predictions, and extends the design rules for synthesizing 2D Janus materials.
Materials Science (cond-mat.mtrl-sci)
17 pages,6 figures
Discrete chiral ballistic polariton laser
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-06 20:00 EST
Zuzanna Werner, Andrzej Frączak, Valtýr Kári Daníelsson, Jacek Szczytko, Barbara Piętka, Helgi Sigurðsson
Orbital angular momentum (OAM) of light appears when the phase of an electromagnetic wavefront winds around its direction of propagation, also known as optical vorticity. Contrary to the binary-valued photon spin, the integer-valued optical vortex charge is unbounded with many advantages in optical communication and trapping and enhancing the capacity of data encoding and multiplexing. Singular optoelectronic and chiroptic quantum technologies rely on the development of coherent and compact light sources of well-defined and reconfigurable OAM. We propose an optically tunable discrete chiral exciton-polariton microlaser that leverages strong spin-dependent polariton interactions, structured pumping, and inherent cavity photon spin-to-angular momentum conversion to emit coherent nonlinear light of variable OAM. By choosing pumping patterns with broken inversion symmetry in the microcavity plane we invoke geometric frustration between spinor ballistic condensates which spontaneously obtain a high-charge circulating current locked with the pump polarization. Our optically configurable system requires only a planar cavity thus avoiding the need for specialized irreversible cavity patterning or metasurfaces.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics)
Can one hear the shape of a crystal?
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-06 20:00 EST
Haina Wang, Salvatore Torquato
Isospectrality is a general fundamental concept often involving whether various operators can have identical spectra, i.e., the same set of eigenvalues. In the context of the Laplacian operator, the famous question ``Can one hear the shape of a drum?'' concerns whether different shaped drums can have the same vibrational modes. The isospectrality of a lattice in \(d\)-dimensional Euclidean space \(\mathbb{R}^d\) is a tantamount to whether it is uniquely determined by its theta series, i.e., the radial distribution function \(g_2(r)\). While much is known about the isospectrality of Bravais lattices across dimensions, little is known about this question of more general crystal (periodic) structures with an \(n\)-particle basis (\(n \ge 2\)). Here, we ask, What is \(n_{\text{min}}(d)\), the minimum value of \(n\) for inequivalent (i.e., unrelated by isometric symmetries) crystals with the same theta function in space dimension \(d\)? To answer these questions, we use rigorous methods as well as a precise numerical algorithm that enables us to determine the minimum multi-particle basis of inequivalent isospectral crystals. Our algorithm identifies isospectral 4-, 3- and 2-particle bases in one, two and three spatial dimensions, respectively. For many of these isospectral crystals, we rigorously show that they indeed possess identical \(g_2(r)\) up to infinite \(r\). Based on our analyses, we conjecture that \(n_{\text{min}}(d) = 4, 3, 2\) for \(d = 1, 2, 3\), respectively. The identification of isospectral crystals enables one to study the degeneracy of the ground-state under the action of isotropic pair potentials.
Soft Condensed Matter (cond-mat.soft), Mathematical Physics (math-ph)
Phys. Rev. Research 6, 043124, 2024
A chain stretch-based gradient-enhanced model for damage and fracture in elastomers
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-06 20:00 EST
S. Mohammad Mousavi, Jason Mulderrig, Brandon Talamini, Nikolaos Bouklas
In this study, we introduce a novel stretch-based gradient-enhanced damage (GED) model that allows the fracture to localize and also captures the development of a physically diffuse damage zone. This capability contrasts with the paradigm of the phase field method for fracture, where a sharp crack is numerically approximated in a diffuse manner. Capturing fracture localization and diffuse damage in our approach is achieved by considering nonlocal effects that encompass network topology, heterogeneity, and imperfections. These considerations motivate the use of a statistical damage function dependent upon the nonlocal deformation state. From this model, fracture toughness is realized as an output. While GED models have been classically utilized for damage modeling of structural engineering materials, they face challenges when trying to capture the cascade from damage to fracture, often leading to damage zone broadening. This deficiency contributed to the popularity of the phase-field method over the GED model for elastomers and other quasi-brittle materials. Other groups have proceeded with damage-based GED formulations that prove identical to the phase-field method (Lorentz et al., 2012), but these inherit the aforementioned limitations. To address this issue in a thermodynamically consistent framework, we implement two modeling features (a nonlocal driving force bound and a simple relaxation function) specifically designed to capture the evolution of a physically meaningful damage field and the simultaneous localization of fracture, thereby overcoming a longstanding obstacle in the development of these nonlocal strain- or stretch-based approaches. We discuss several numerical examples to understand the features of the approach at the limit of incompressibility, and compare them to the phase-field method as a benchmark for the macroscopic response and fracture energy predictions.
Soft Condensed Matter (cond-mat.soft)
Supercooled Liquid Water Diffusivity at Temperatures near the Glass Transition Temperature
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-06 20:00 EST
R. Scott Smith, Wyatt A. Thornley, Greg A. Kimmel, Bruce D. Kay
Isotopically layered amorphous solid water films were used to measure the diffusivity of deeply supercooled liquid water near the glass transition. The films, composed of separate layers of oxygen 16 and oxygen 18 labeled water, were grown by vapor deposition at low temperature and then heated to observe the intermixing of the isotopic layers. Very slow heating rates (as low as 0.0001 K/s) were used to decouple the diffusion and crystallization processes to ensure that the observed intermixing occurred at temperatures that were well-separated from the onset of crystallization. Numerical simulations of the desorption spectra were used to extract the translational diffusivities. The diffusivities obtained in this paper are consistent with translational liquid-like motion at temperatures near and above the proposed Tg of 136 K. These findings support the idea that the melt of amorphous water, above its glass transition temperature is thermodynamically continuous with normal supercooled liquid.
Soft Condensed Matter (cond-mat.soft), Chemical Physics (physics.chem-ph)
Nudged elastic band calculations of stacking and dislocation pathways in diamond
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-06 20:00 EST
Chunxia Chi, Hairui Ding, Xiang-Feng Zhou, Xiao Dong
Diamond, the hardest natural crystal, has attracted significant attention for its plasticity, which is reported to be determined by its stacking faults. Studies mainly focused on one-dimensional linear pathways in stacking transitions, neglecting its transverse freedom on the main slip plane. However, in an actual stacking procedure, stacking faults can follow curve line along the slip plane rather than constrained to straight lines. In this study, using ab initio calculations, we mapped the {}-surface, defined as the landscape of generalized stacking fault energies, along the weakest direction of the {111} orientation in diamond. We then applied the Nudged Elastic Band (NEB) method to determine the minimum energy paths, finding significantly reduced stacking energy barriers compared to previous reports (for the glide-set, our energy barrier is only one-third of that for the traditional direct path). Our calculations reveal that the glide-set can round its high-energy peak, with a lower energy barrier within the entire stacking plane than the shuffle-set. By employing the NEB method, we have constructed the minimum energy path (MEP) for both the stacking and dislocation procedures. Our results provide new insights into the plasticity and stacking faults of diamond, advancing the understanding of superhard carbon material transition, especially the diamond under shear stress.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
AI-driven materials design: a mini-review
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-06 20:00 EST
Mouyang Cheng, Chu-Liang Fu, Ryotaro Okabe, Abhijatmedhi Chotrattanapituk, Artittaya Boonkird, Nguyen Tuan Hung, Mingda Li
Materials design is an important component of modern science and technology, yet traditional approaches rely heavily on trial-and-error and can be inefficient. Computational techniques, enhanced by modern artificial intelligence (AI), have greatly accelerated the design of new materials. Among these approaches, inverse design has shown great promise in designing materials that meet specific property requirements. In this mini-review, we summarize key computational advancements for materials design over the past few decades. We follow the evolution of relevant materials design techniques, from high-throughput forward machine learning (ML) methods and evolutionary algorithms, to advanced AI strategies like reinforcement learning (RL) and deep generative models. We highlight the paradigm shift from conventional screening approaches to inverse generation driven by deep generative models. Finally, we discuss current challenges and future perspectives of materials inverse design. This review may serve as a brief guide to the approaches, progress, and outlook of designing future functional materials with technological relevance.
Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG)
18 pages, 7 figures, 1 table; Review article
Quantitative thermodynamic analyses of nucleation, evolution and stabilization of surface nanobubbles
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-06 20:00 EST
Lili Lan, Yongcai Pan, Liang Zhao, Binghai Wen
Surface nanobubbles are complex micro- and nanoscale fluid systems. While thermodynamics is believed to dominate nanobubble dynamics, the precise mechanism by which nanobubble evolution is driven by thermodynamics remains unclear. It is essential to understand how nanobubble nucleation and growth, nanoscale contact line movement, and gas diffusion across the liquid-bubble interface are simultaneously driven by the change in free energy, leading to the ultimate thermodynamic equilibrium of surface nanobubble systems. In this paper, we first propose a quantitative theoretical model to elucidate the thermodynamic dominance behind the dynamics and stability of the fluid system with surface nanobubbles. The present model demonstrates that thermodynamic non-equilibrium drives the gas diffusion and the contact line motion of surface nanobubbles. Overcoming the nucleation energy barrier is crucial for bubble nucleation and growth. Surface nanobubbles evolve towards the reduction of the system's free energy and stabilize at the state with minimum free energy. The thermodynamic equilibrium is accompanied by the mechanical equilibrium at the contact line and the gas diffusion equilibrium at the liquid-bubble interface, and the theoretical results are in excellent agreement with the nanobubble morphology observed in experiments. The study highlights the significant influence of gas properties and ambient conditions in promoting bubble nucleation and stability.
Soft Condensed Matter (cond-mat.soft), Computational Physics (physics.comp-ph), Fluid Dynamics (physics.flu-dyn)
Revealing the orbital origins of exotic electronic states with Ti substitution in kagome superconductor CsV3Sb5
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-06 20:00 EST
Zihao Huang, Hui Chen, Hengxin Tan, Xianghe Han, Yuhan Ye, Bin Hu, Zhen Zhao, Chengmin Shen, Haitao Yang, Binghai Yan, Ziqiang Wang, Feng Liu, Hong-Jun Gao
The multiband kagome superconductor CsV3Sb5 exhibits complex orbital textures on the Fermi surface, making the orbital origins of its cascade of correlated electronic states and superconductivity a major scientific puzzle. Chemical doping of the kagome plane can simultaneously tune the exotic states and the Fermi-surface orbital texture, and thus offers a unique opportunity to correlate the given states with specific orbitals. In this Letter, by substituting V atoms with Ti in kagome superconductor CsV3Sb5, we reveal the orbital origin of a cascade of its correlated electronic states through the orbital-resolved quasiparticle interference (QPI). We analyze the QPI changes associated with different orbitals, aided by first-principles calculations. We have observed that the in-plane and out-of-plane vanadium 3d orbitals cooperate to form unidirectional coherent states in pristine CsV3Sb5, whereas the out-of-plane component disappears with doping-induced suppression of charge density wave and global electronic nematicity. In addition, the Sb pz orbital plays an important role in both the pseudo-gap and superconducting states in CsV3Sb5. Our findings offer new insights into multiorbital physics in quantum materials which are generally manifested with intriguing correlations between atomic orbitals and symmetry-encoded correlated electronic states.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci)
7 pages, 4 figures
Phys. Rev. Lett. 134, 056001 (2025)
Exclusive Generation of Single-Atom Sulfur for Ultrahigh Quality Monolayer MoS\(_2\) Growth
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-06 20:00 EST
Yunhao Zhang, Jingwei Wang, Yumo Chen, Xian Wu, Junyang Tan, Jiarong Liu, Huiyu Nong, Liqiong He, Qinke Wu, Guangmin Zhou, Xiaolong Zou, Bilu Liu
Preparation of high-quality two-dimensional (2D) transition metal dichalcogenides (TMDCs) is the precondition for realizing their applications. However, the synthesized 2D TMDCs (e.g., MoS\(_2\)) crystals suffer from low quality due to the massive defects formed during the growth. Here, we report the single-atom sulfur (S1) as a highly reactive sulfur species to grow ultrahigh-quality monolayer MoS\(_2\). Derived from battery waste, the sulfurized polyacrylonitrile (SPAN) is found to be exclusive and efficient in releasing S1. The monolayer MoS\(_2\) prepared by SPAN exhibits an ultralow defect density of \(~7\times 10^{12}\) cm\(^{-2}\) and the narrowest photoluminescence (PL) emission peak with full-width at half-maximum of ~47.11 meV at room temperature. Moreover, the statistical resonance Raman and low-temperature PL results further verify the significantly lower defect density and higher optical quality of SPAN-grown MoS\(_2\) than the conventional S-powder-grown samples. This work provides an effective approach for preparing ultrahigh-quality 2D single crystals, facilitating their industrial applications.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
15 pages, 4 figures. Journal of the American Chemical Society, 2024, 146, 49, 33289
JACS, 2024
Superconductivity and magnetic ordering in chalcogen-intercalated graphene bilayers with charge compensation
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-06 20:00 EST
This work introduces a new class of two-dimensional crystals with the structure AC\(_8\)XC\(_8\), consisting of two layers of graphene, a chalcogen (X = O, S, Se, Te) intercalation layer, and an alkaline earth (A = Be, Ca, Mg, Sr, Ba) adlayer. The electronic band structure for the 20 compounds was studied using density functional theory. The chalcogen \(p\) orbitals interact with the carbon \(\pi\) orbitals to form weakly dispersing bands that intersect the Fermi level and give rise to complex Fermi surfaces featuring electron and hole pockets whose densities exactly compensate each other, and van Hove singularities that are very close to, or coincident with, the Fermi level in the majority of compounds studied. The resulting electron-electron interaction effects are studied using both the temperature-flow renormalisation group approach and a spin fluctuation model, which show a ferromagnetic phase with critical temperatures as high as \(\sim 10^3\) K that coexists with \(p\)- or \(f\)-wave spin triplet superconductivity over a range of temperatures.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Superconductivity (cond-mat.supr-con)
8 pages (main text), 10 pages supplemental material
Pervasive symmetry-lowering nanoscale structural fluctuations in the cuprate La\(_{2-x}\)Sr\(_{x}\)CuO\(_{4}\)
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-06 20:00 EST
R. J. Spieker, M. Spaić, I. Khayr, X. He, D. Zhai, Z. W. Anderson, N. Bielinski, F. Ye, Y. Liu, S. Chi, S. Sarker, M. J. Krogstad, R. Osborn, D. Pelc, M. Greven
The cuprate superconductors are among the most widely studied quantum materials, yet there remain fundamental open questions regarding their electronic properties and the role of the structural degrees of freedom. Recent neutron and x-ray scattering measurements uncovered exponential scaling with temperature of the strength of orthorhombic fluctuations in the tetragonal phase of \(La_{2-x}Sr_xCuO_4\) and \(Tl_2Ba_2CuO_{6+y}\), unusual behavior that closely resembles prior results for the emergence of superconducting fluctuations, and that points to a common origin rooted in inherent correlated structural inhomogeneity. Here we extend the measurements of \(La_{2-x}Sr_xCuO_4\) to higher temperatures in the parent compound (x=0) and to optimal doping (x=0.155), and we furthermore investigate the effects of in-situ in-plane uniaxial stress. Our neutron scattering result for undoped \(La_2CuO_4\) complement prior x-ray data and reveal that the structural fluctuations persist to the maximum experimental temperature of nearly 1000K, i.e., to a significant fraction of the melting point. At this temperature, the spatial correlation length extracted from the momentum-space data is still about three lattice constants. The neutron scattering experiment enables quasistatic discrimination and reveals that the response is increasingly dynamic at higher temperatures. We also find that uniaxial stress up to 500 MPa along the tetragonal [110] direction, which corresponds to a strain of about 0.2%, does not significantly alter this robust behavior. Overall, these results support the notion that subtle, underlying inhomogeneity underpins the cuprate phase diagram. Finally, we uncover (for x=0.2) low-energy structural fluctuations at a nominally forbidden reflection. While the origin of these fluctuations is not clear, they might be related to the presence of extended defects such as dislocations or stacking faults.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
20 pages, 6 figures
Dipolar and quadrupolar correlations in the \(5d^2\) Re-based double perovskites Ba\(_2\)YReO\(_6\) and Ba\(_2\)ScReO\(_6\)
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-06 20:00 EST
Otkur Omar, Yang Zhang, Qiang Zhang, Wei Tian, Elbio Dagotto, Gang Chen, Taka-hisa Arima, Matthew B. Stone, Andrew D. Christianson, Daigorou Hirai, Shang Gao
Double perovskites containing heavy transition metal ions are an important family of compounds for the study of the interplay between electron correlation and spin-orbit coupling. Here, by combining magnetic susceptibility, heat capacity, and neutron scattering measurements, we investigate the dipolar and quadrupolar correlations in two prototype rhenium-based double perovskite compounds, Ba\(_2\)YReO\(_6\) and Ba\(_2\)ScReO\(_6\). A type-I dipolar antiferromagnetic ground state with a propagation vector \(\mathbf{q} = (0, 0, 1)\) is observed in both compounds. At temperatures above the magnetic transitions, a quadrupolar ordered phase is identified. Weak spin excitations, which are gapped at low temperatures and softened in the correlated paramagnetic phase, are explained using a minimal model that considers both the dipolar and quadrupolar interactions. At larger wavevectors, we observe dominant phonon excitations that are well described by density functional calculations.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
13 pages, 11 figures
Observation of slow relaxation due to Hilbert space fragmentation in strongly interacting Bose-Hubbard chains
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-02-06 20:00 EST
Kantaro Honda, Yosuke Takasu, Shimpei Goto, Hironori Kazuta, Masaya Kunimi, Ippei Danshita, Yoshiro Takahashi
While isolated quantum systems generally thermalize after long-time evolution, there are several exceptions defying thermalization. A notable mechanism of such nonergodicity is the Hilbert space fragmentation (HSF), where the Hamiltonian matrix splits into an exponentially large number of sectors due to the presence of nontrivial conserved quantities. Using ultracold gases, here we experimentally investigate the one-dimensional Bose-Hubbard system with neither disorder nor tilt potential, which has been predicted to exhibit HSF caused by a strong interatomic interaction. Specifically, we analyze far-from-equilibrium dynamics starting from a charge-density wave of doublons (atoms in doubly occupied sites) in a singlon and doublon-resolved manner to reveal a slowing-down of the relaxation in a strongly interacting regime. We find that the numbers of singlons and doublons are conserved during the dynamics, indicating HSF as a mechanism of the observed slow relaxation. Our results provide the first experimental confirmation of the conserved quantities responsible for HSF.
Quantum Gases (cond-mat.quant-gas), Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
18 pages, 7 figures
Elimination of substrate-induced FMR linewidth broadening in the epitaxial system YIG-GGG by microstructuring
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-06 20:00 EST
David Schmoll, Rostyslav O. Serha, Jaganandha Panda, Andrey A. Voronov, Carsten Dubs, Michal Urbánek, Andrii V. Chumak
Modern quantum technologies and hybrid quantum systems offer the opportunity to utilize magnons on the level of single excitations. Long lifetimes, low decoherence rates, and a strong coupling rate to other subsystems propose the ferrimagnet yttrium iron garnet (YIG), grown on a gadolinium gallium garnet (GGG) substrate, as a suitable platform to host magnonic quantum states. However, the magnetic damping at cryogenic temperatures significantly increases due to the paramagnetic character and the highly inhomogeneous stray field of GGG, as recent experiments and simulations pointed out. Here, we report on temperature dependent ferromagnetic resonance (FMR) spectroscopy studies in YIG-GGG thin-films with different sample geometries. We experimentally demonstrate how to eliminate the asymmetric stray field-induced linewidth broadening via microstructuring of the YIG film. Additionally, our experiments reveal evidence of a non-Gilbert like behavior of the linewidth at cryogenic temperatures, independent of the inhomogeneous GGG stray field.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
8 pages, 3 figures
Robust spin-orbit coupling in semi-metallic SrIrO3 under hydrostatic pressure
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-06 20:00 EST
Dirk Fuchs, Arun Kumar Jaiswal, Fabrice Wilhelm, Di Wang, Andre Rogalev, Matthieu Le Tacon
The semi-metallic behavior of the perovskite iridate SrIrO3 shifts
the end-member of the strongly spin-orbit (SO) coupled Ruddlesden-Popper
series Srn+1IrnO3n+1 away from the Mott insulating regime and the
half-filled pseudospin Jeff=1/2 ground state well-established in the
layered iridates (n = 1 and 2). To investigate the robustness of the SO
coupled ground state of SrIrO3, X-ray absorption spectroscopy was
carried out at the Ir L2,3 edges under hydrostatic pressure up to 50 GPa
at room temperature. The effective SO coupling was deduced from the
branching ratio of the Ir L2 and L3 white lines. With increasing
pressure, the branching ratio decreases, and the Ir L2,3 peak positions
shift to higher energies. The number of 5d holes remains constant
indicating that the spectral weight redistribution and peak shifts arise
from orbital mixing between t2g and eg related states. The expectation
value of the angular part of the SO operator
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
accepeted in Physical Review B
Thermoelastic Damping Across the Phase Transition in van der Waals Magnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-06 20:00 EST
Alvaro Bermejillo-Seco, Xiang Zhang, Maurits J.A. Houmes, Makars Šiškins, Herre S.J. van der Zant, Peter G. Steeneken, Yaroslav M. Blanter
A quantitative understanding of the microscopic mechanisms responsible for damping in van der Waals nanomechanical resonators remains elusive. In this work, we investigate van der Waals magnets, where the thermal expansion coefficient exhibits an anomaly at the magnetic phase transition due to magnetoelastic coupling. Thermal expansion mediates the coupling between mechanical strain and heat flow and determines the strength of thermoelastic damping (TED). Consequently, variations in the thermal expansion coefficient are reflected directly in TED, motivating our focus on this mechanism. We extend existing TED models to incorporate anisotropic thermal conduction, a critical property of van der Waals materials. By combining the thermodynamic properties of the resonator material with the anisotropic TED model, we examine dissipation as a function of temperature. Our findings reveal a pronounced impact of the phase transition on dissipation, along with transitions between distinct dissipation regimes controlled by geometry and the relative contributions of in-plane and out-of-plane thermal conductivity. These regimes are characterized by the resonant interplay between strain and in-plane or through-plane heat propagation. To validate our theory, we compare it to experimental data of the temperature-dependent mechanical resonances of FePS\(_3\) resonators.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
16 pages, 8 figures
Significant Chiral Magnetotransport Magnified by Multiple Weyl Nodes
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-06 20:00 EST
Bo Zhang, Junbo Liao, Zhentao Huang, Yanyan Shangguan, Shufan Cheng, Hao Xu, Zihang Song, Shuai Dong, Song Bao, Rui Wang, Jinsheng Wen
The intertwining of magnetism with topology is known to give rise to exotic quantum phenomena. Here, we explore the magnetotransport properties of NdAlSi, a magnetic Weyl semimetal that spontaneously breaks inversion and time-reversal symmetries and hosts a large number of Weyl nodes. We observe a significant negative magnetoresistance, which we attribute to the chiral anomaly associated with multiple Weyl nodes. Remarkably, the extracted chiral coefficient reaches approximately \(52~\mathrm{m\Omega}^{-1}~\mathrm{m}^{-1}~\mathrm{T}^{-2}\), larger than many other topological materials. Additionally, we observe an exotic anomalous Hall effect with an out-of-sync behavior, where the anomalous Hall resistance does not exactly follow the field dependence of the magnetization, in contrast to that in conventional ferromagnets. These rich quantum transport phenomena, driven by the interplay between magnetism and Weyl nodes, establish NdAlSi as a prime platform for exploring the intricate topological behaviors of magnetic Weyl semimetals.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
10 pages, 8 figures
Phys. Rev. B 111, 045163 (2025)
Spin-valley polarization control in WSe\(_2\) monolayers using photochemical doping
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-06 20:00 EST
E. Katsipoulaki, K. Mourzidis, V. Jindal, D. Lagarde, T. Taniguchi, K. Watanabe, G. Kopidakis, X. Marie, M.M. Glazov, E. Stratakis, G. Kioseoglou, I. Paradisanos
We report on the influence of a photochemical doping method on the spin-valley polarization degree (\(P_{c}\)) of excitons in WSe\(_2\) monolayers. By varying the carrier density and transitioning from an excess of electrons (n-type) to an excess of holes (p-type), we observe a non-monotonic dependence of \(P_{c}\) on the doping level. Using controlled, single-shot photochlorination steps, we unveil this non-monotonic behavior, with \(P_{c}\) reaching a minimum value of less than 10\(\%\) at 78 K near the charge neutrality point, while increasing by a factor of three at a hole density of \(5 \times 10^{11} \,\mathrm{cm^{-2}}\). The impact of the doping on \(P_{c}\) is explained using a phenomenological model that accounts for various mechanisms influencing exciton polarization dynamics, including exciton-carrier scattering processes and exciton-to-trion conversion rates. Among these, exciton-carrier collisions emerge as the dominant mechanism driving the observed variations in \(P_{c}\), while the exciton effective lifetime remains nearly independent of doping. These findings highlight the potential of photochemical methods for investigating valley physics and for effectively tuning the exciton polarization degree in transition metal dichalcogenide monolayers.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
8 pages, 4 figures
Imprinting of skyrmions and bimerons in an antiferromagnet
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-06 20:00 EST
Coline Thevenard, Miina Leiviskä, Richard F. L. Evans, Daria Gusakova, Vincent Baltz
Topologically protected magnetic states in condensed matter physics, particularly antiferromagnetic (AFM) skyrmions (Sks) and bimerons (Bms), offer promising prospects for terahertz dynamics and sustained current-induced motion, thanks to their compensating multiple sub-lattice structure. However, nucleating AFM Sks and Bms is challenging due to the lack of net magnetization. Previous attempts to imprint pre-defined Sks and Bms in a ferromagnet (FM) and transfer them to an AFM using interfacial exchange bias in FM/AFM heterostructures have been hindered by complex multilayers with discontinuities, polycrystallinity, or multipartite chiral AFMs. Employing atomistic spin simulations, we demonstrate the viability of texture imprinting for nucleating Sks and Bms in AFMs, using a prototypical bipartite AFM layer in a multilayer structure free from discontinuities. Such imprinting is a crucial step towards understanding the static and dynamic properties of natural antiferromagnetic textures and their unique properties.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Optical Properties of Aluminium-Doped Zinc Oxide Thin Films Synthesized via AACVD Using Nitrogen as a Carrier Gas
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-06 20:00 EST
Kingsley Imoni-Ogbe, Onyekachukwu Mike Osiele, Vincent Akpoveta, Queen Umudi, Bright Ugbolu, Oscar Enajite
The study uses AACVD technology with nitrogen carrier gas to make AZO thin films through which it determines structural, optical, and morphological changes from 0 to 20 percent aluminum doping. The depositions took place at 400 degrees Celsius on soda-lime glass before the samples received an annealing process at 450 degrees Celsius inside a nitrogen chamber. The X-ray diffraction analysis identified superior crystalline structure in films processed with nitrogen gas through their strong signals at the 220, 311 and 222 peaks. The increasing levels of aluminum doping decreased the crystallite dimensions and elevated grain boundary concentrations because of intensified crystal tension and defective structural formation. The profilometry assessment determined film thickness increased mildly from 102 nanometers in undoped ZnO to 115 nanometers in 20 percent aluminum-doped ZnO. The presence of nitrogen annealing in the films led to increased absorbance while the strongest absorbance peaks occurred when the material contained 5 percent dopants. The bandgap energy expanded through the change from undoped ZnO with 3.21 electron volts to 3.33 electron volts at 20 percent aluminum doping which matched Burstein-Moss effect results. The optoelectronic devices gain enhanced optical characteristics from the doping levels exceeding 15 percent.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
21 pages, 15 figures and 2 tables, experimental research
Operando imaging of crystal structure and orientation in all components of all-solid-state-batteries
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-06 20:00 EST
Quentin Jacquet (1), Jacopo Cele (2,3), Lara Casiez (2), Samuel Tardif (4), Asma Medjaheh (5), Stephanie Pouget (4), Manfred Burghammer (5), Sandrine Lyonnard (1), Sami Oukassi (2) ((1) Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, IRIG, SyMMES, Grenoble, France, (2) Univ. Grenoble Alpes, CEA, Leti Grenoble, France (3) ICMMO (UMR CNRS 8182) Univ. Paris-Sud Univ. Paris-Saclay Orsay, France (4) University Grenoble Alpes, CEA, CNRS, IRIG, MEM, Grenoble, France (5) European Synchrotron Radiation Facility (ESRF), CS 40220, Grenoble, France)
A comprehensive understanding of interactions between cathode, electrolyte, anode, and packaging during battery operation is crucial for advancing performances but remains overlooked due to the lack of characterisation technics capable of measuring these components simultaneously. We perform a holistic investigation of a compact all-solid-state-battery using operando synchrotron X-ray micro-diffraction imaging. We image in real time and simultaneously the lattice parameter and crystal orientation of the dense LiCoO2 cathode, the Ti current collector and the electrodeposited Li metal anode. We reveal that reaction mechanism of LiCoO2 depends on the crystal orientation, and that, in dense electrodes as opposed to porous ones, the delithiation is limited by the formation of a Li-rich insulating interface. Li metal crystal orientation is found to be influenced initially by the Ti texture and to change within minutes during plating and stripping. These results demonstrate the power of X-ray imaging to link reaction mechanism and grain orientation during non-equilibrium processes.
Materials Science (cond-mat.mtrl-sci)
Altermagnetic spin splitting and symmetry-enforced partial spin degeneracy in hexagonal MnTe
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-06 20:00 EST
Besides hosting several intriguing physical properties, the recently discovered time-reversal-asymmetric antiferromagnets, known as altermagnets, hold immense promise for technologies based on spintronics. Understanding the symmetry conditions leading to the spin-splitting becomes the key to further progress in the field. Hexagonal MnTe emerges as an even-parity magnet within the altermagnet family. In this work, using ab initio density functional theory (DFT) within a combination of an appropriate exchange-correlation functional and the relevant corrections, we uncover the spin-splitting features of MnTe. Our calculations reveal the spin degeneracy to be preserved in the \(k_z = 0\) and \(k_y = 0\) planes, while spin-splitting is observed everywhere else in the Brillouin zone, except the nodal lines identified here. To explain these findings, we provide a comprehensive symmetry analysis based on magnetic space group theory and introduce an insightful symmetry-adapted model Hamiltonian that qualitatively describes the spin-splitting behavior in different parts of the Brillouin zone. Our calculations considering spin-orbit interaction reveal no weak ferromagnetism in MnTe. Nevertheless, we discuss plausible explanations for weak ferromagnetism and anomalous Hall effect reported from experiments. Our comprehensive analysis of the magnetic space group symmetry and the DFT results leads to a thorough understanding of altermagnetism in MnTe, paving the way for possible future technology.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
13 pages, 8 figures
Electronic structure property relationship in glassy Ti-Zr-Nb-(Cu,Ni,Co)
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-06 20:00 EST
Marko Kuveždić, Emil Tafra, Emil Babić, Ramir Ristić, Krešo Zadro, Damir Starešinić, Ignacio A. Figueroa, Mario Basletić
In this work we revisit vast amount of existing data on physical properties of Ti-Zr-Nb-(Cu,Ni,Co) glassy alloys over a broad range of concentrations (from the high entropy range to that of conventional Cu-, Ni- or Co-rich alloys). By using our new approach based on total content of late transition metal(s), we derive a number of physical parameters of a hypothetical amorphous TiZrNb alloy: lattice parameter \(a = (3.42 \pm 0.02)\)Å, Sommerfeld coefficient \(\gamma = 6.2\,\)mJ/mol\(\,\)K\(^2\), density of states at \(N(E_F) = 2.6\,(\text{at eV})^{-1}\), magnetic susceptibility \((2.00 \pm 0.05)\,\)mJ/T\(^2\,\)mol, superconducting transition temperature \(T_c = (8 \pm 1)\,\)K, upper critical field \(\mu_0 H_{c2}(0) = (20 \pm 5)\,\)T, and coherence length \(\xi(0) = (40 \pm 3)\,\)Å. We show that our extrapolated results for amorphous TiZrNb alloy would be similar to that of crystalline TiZrNb, except for superconducting properties (most notably the upper critical field \(H_{c2}(0)\)), which might be attributed to the strong topological disorder of the amorphous phase. Also, we offer an explanation of the discrepancy between the variations of \(T_c\) with the average number of valency electrons in neighboring alloys of 4d transition metals and some high entropy alloys. Overall, we find that our novel method of systematic analysis of results is rather general, as it can provide reliable estimates of the properties of any alloy which has not been prepared as yet.
Materials Science (cond-mat.mtrl-sci)
27 pages, 7 figures
Symmetry Preservation in Commensurate Twisted Bilayers
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-06 20:00 EST
Symmetry plays a key role in materials hosting Dirac electrons and underpins our ability to completely flatten the Dirac cone through the tuning of physical parameters such as twisting in van der Waals heterostructures. The emergent moiré patterns in twisted bilayers at small twist angles appear, at first glance, to be independent of the initial stacking order and hence are only shifted when one layer is translated with respect to the other. However, when the twist angle is large, differences can be seen at the level of both the lattice and electronic structure in the case of twisted bilayer graphene. In this work, we first address the problem of twisted Kagome bilayers and show that the rotational and dihedral symmetry of high-symmetry Kagome bilayers is preserved for all commensurate twist angles with a 6-fold symmetric twist centre. Hence, we demonstrate that the exact symmetry of small twist angle systems depends upon the initial stacking of the bilayer. We further apply the principles of our method to twisted bilayer graphene with a 3-fold symmetric twist centre to recover the results of [E. J. Mele, Phys. Rev. B 81, 161405 (2010)].
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
11 pages, 2 figures
Thermal transport of amorphous hafnia across the glass transition
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-06 20:00 EST
Zezhu Zeng, Xia Liang, Zheyong Fan, Yue Chen, Michele Simoncelli, Bingqing Cheng
Heat transport in glasses across a wide range of temperature is vital for applications in gate dielectrics and heat insulator. However, it remains poorly understood due to the challenges of modeling vibrational anharmonicity below glass transition temperature and capturing configurational dynamics across the transition. Interestingly, recent calculations predicted that amorphous hafnia (a-HfO\(_2\)) exhibits an unusual drop in thermal conductivity (\(\kappa\)) with temperature, contrasting with the typical rise or saturation observed in glasses upon heating. Using molecular dynamics simulations with a machine-learning-based neuroevolution potential, we compute the vibrational properties and \(\kappa\) of a-HfO\(_2\) from 50~K to 2000~K. At low temperatures, we employ the Wigner transport equation to incorporate both anharmonicity and Bose-Einstein statistics of atomic vibration in the calculation of \(\kappa\). At above 1200~K, atomic diffusion breaks down the Lorentzian-shaped quasiparticle picture and makes the lattice-dynamics treatment invalid. We thus use molecular dynamics with the Green-Kubo method to capture convective heat transport in a-HfO\(_2\) near the glass transition at around 1500~K. Additionally, by extending the Wigner transport equation to supercooled liquid states, we find the crucial role of low-frequency modes in facilitating heat convection. The computed \(\kappa\) of a-HfO\(_2\), based on both Green-Kubo and Wigner transport theories, reveals a continuous increase with temperature up to 2000~K.
Materials Science (cond-mat.mtrl-sci), Disordered Systems and Neural Networks (cond-mat.dis-nn)
A Robust Machine Learned Interatomic Potential for Nb: Collision Cascade Simulations with accurate Defect Configurations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-06 20:00 EST
Utkarsh Bhardwaj, Vinayak Mishra, Suman Mondal, Manoj Warrier
Niobium (Nb) and its alloys are extensively used in various technological applications owing to their favorable mechanical, thermal and irradiation properties. Accurately modeling Nb under irradiation is essential for predicting microstructural changes, defect evolution, and overall material performance. Traditional interatomic potentials for Nb fail to predict the correct self-interstitial atom (SIA) configuration, a critical factor in radiation damage simulations. We develop a machine learning interatomic potential (MLIP) using the Spectral Neighbor Analysis Potential (SNAP) framework, trained on ab-initio Density Functional Theory (DFT) calculations, which accurately captures the relative stability of different SIA dumbbell configurations. The resulting potential reproduces DFT-level accuracy while maintaining computational efficiency for large-scale Molecular Dynamics (MD) simulations. Through a series of validation tests involving elastic, thermal, and defect properties -- including collision cascade simulations -- we show that our SNAP potential resolves persistent limitations in existing Embedded Atom Method (EAM) and Finnis--Sinclair (FS) potentials and is effective for MD simulations of collision cascades. Notably, it accurately captures the ground-state SIA configuration of Nb in the primary damage of a collision cascade, offering a robust tool for predictive irradiation studies.
Materials Science (cond-mat.mtrl-sci)
Magnetic texture control in ion-implanted metamaterials
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-06 20:00 EST
Christina Vantaraki, Kristina Ignatova, Dmitrii Moldarev, Matías P. Grassi, Michael Foerster, Daniel Primetzhofer, Unnar B. Arnalds, Vassilios Kapaklis
We study experimentally the impact of the additive fabrication method on the magnetic properties of Fe\(^+\)-implanted Pd square artificial spin ice lattices. Our findings show that these lattices undergo magnetic collapse at higher temperatures than their continuous film counterparts. This behavior is attributed to the additive fabrication process, which induces an inhomogeneous Fe concentration within the lattice building blocks. Moreover, the implantation process creates a magnetic depth profile, enabling temperature-dependent tunability of the magnetic thickness. These additional internal degrees of freedom broaden the design possibilities for magnetic metamaterials, allowing precise fine-tuning of their static and dynamic properties to achieve complex and customizable behaviors.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph)
11 pages, 8 figures
Ultra-giant Tunneling Magnetoresistance with Two-dimensional Altermagnetic MBene electrode: from material design to device modeling
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-06 20:00 EST
Weiwei Sun, Mingzhuang Wang, Litao Sun, Baisheng Sa, Shaui Dong, Raghottam M Sattigeri, Carmine Autieri
Altermagnetism is an emerging series of unconventional magnetic materials characterized by time-reversal symmetry breaking and spin-split bands in the momentum space with zero net magnetization. Metallic altermagnets offer unique advantages for exploring applications in spintronics as conductive metals allows for serving as electrode in magnetic tunneling junction (MTJ) and/or manipulation of spincurrent through external field. Through density functional theory calculations, the 2D altermagnet Cr4B3N was predicted to be stable, resulting from a N atom substitution in the FeSe-like CrB bilayer. Both intra- and inter-layered magnetic exchanges between Cr atoms are in antiferromagnetic with the first three neighbours. Leveraging the anisotropic spin-splittings with momentum dependency revealed in band structure, we designed three edge dependent Cr4B3N/square/Cr4B3N in-plane MTJs with the 7 Åvaccume the barrie. We found that the Cr-B vertical edge-assembled electrodes based MTJs exhibited giant tunneling magnetoresistance (TMR) ratios of 91001% , by aligning the conduction channels of the electrodes in parallel and anti-parallel states in the momentum space. Our work deepens and generalizes understanding toward altermagnetic 2D metallic electrode with a newly established metal boride (MBene), and broadens applications of the nanoscale spintronics.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Thermal spin wave noise as a probe for the Dzyaloshinkii-Moriya interaction
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-06 20:00 EST
Aurore Finco, Pawan Kumar, Van Tuong Pham, Joseba Urrestarazu-Larrañaga, Rodrigo Guedas Garcia, Maxime Rollo, Olivier Boulle, Joo-Von Kim, Vincent Jacques
Interfacial Dzyaloshinkii-Moriya interaction (DMI) is a key ingredient in the stabilization of chiral magnetic states in thin films. Its sign and strength often determine crucial properties of magnetic objects, like their topology or how they can be manipulated with currents. A few experimental techniques are currently available to measure DMI quantitatively, based on the study of domain walls, spin waves, or spin-orbit torques. In this work, we propose a qualitative variant of spin wave methods. We rely on magnetic noise from confined thermal spin waves in domain walls and skyrmions in perpendicularly magnetized thin films, which we probe with scanning NV center relaxometry. We show both numerically and experimentally that the sign of the DMI can be inferred from the amplitude of the detected noise, which is affected by the non-reciprocity in the spin wave dispersion. Furthermore, we also demonstrate that the noise distribution around the contour of magnetic skyrmions reveals their Néel/Bloch nature, giving therefore also insight into the strength of DMI involved in their stabilization.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
6 pages, 4 figures, supplemental material available as ancillary file
Cavity engineering of solid-state materials without external driving
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-06 20:00 EST
I-Te Lu, Dongbin Shin, Mark Kamper Svendsen, Simone Latini, Hannes Hübener, Michael Ruggenthaler, Angel Rubio
Confining electromagnetic fields inside an optical cavity can enhance the light-matter coupling between quantum materials embedded inside the cavity and the confined photon fields. When the interaction between the matter and the photon fields is strong enough, even the quantum vacuum field fluctuations of the photons confined in the cavity can alter the properties of the cavity-embedded solid-state materials at equilibrium and room temperature. This approach to engineering materials with light avoids fundamental issues of laser-induced transient matter states. To clearly differentiate this field from phenomena in driven systems, we call this emerging field cavity materials engineering. In this review, we first present theoretical frameworks, especially, ab initio methods, for describing light-matter interactions in solid-state materials embedded inside a realistic optical cavity. Next, we overview a few experimental breakthroughs in this domain, detailing how the ground state properties of materials can be altered within such confined photonic environments. Moreover, we discuss state-of-the-art theoretical proposals for tailoring material properties within cavities. Finally, we outline the key challenges and promising avenues for future research in this exciting field.
Materials Science (cond-mat.mtrl-sci), Optics (physics.optics), Quantum Physics (quant-ph)
75 pages, 8 figures
Epitaxial strain tuning of electronic and spin excitations in La\(_3\)Ni\(_2\)O\(_7\) thin films
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-06 20:00 EST
Hengyang Zhong, Haobo, Yuan Wei, Zhijia Zhang, Ruixian Liu, Xinru Huang, Xiao-Sheng Ni, Marli dos Reis Cantarino, Kun Cao, Yuefeng Nie, Thorsten Schmitt, Xingye Lu
The discovery of ambient-pressure superconductivity with \(T_{c,\text{onset}} > 40\) K in La\(_3\)Ni\(_2\)O\(_7\) (LNO) thin films under in-plane biaxial compressive strain underscores the pivotal role of epitaxial strain in tuning exotic electronic states and provides a unique platform for investigating the superconducting mechanisms in nickelate superconductors. Here, we use resonant inelastic X-ray scattering (RIXS) to probe the strain-dependent electronic and spin excitations in LNO thin films with biaxial strain ranging from \(\epsilon\approx-1.04\%\) to \(1.91\%\). Compared with the bulk crystal, the LNO thin film grown on LaAlO\(_3\) (with \(\epsilon\approx-1.04\%\)) exhibits similar \(dd\) excitations and enhanced spin excitation bandwidth. In contrast, the 0.4 eV and 1.6 eV \(dd\) excitations associated with the Ni 3\(d_{z^2}\) orbital, along with the spin excitations, are significantly suppressed in the film grown on SrTiO\(_3\) (\(\varepsilon\approx1.91\%\)). The \(c\)-axis compression and the reduced out-of-plane Ni-O-Ni bond angle, induced by in-plane tensile strain in LNO/SrTiO\(_3\) broaden the Ni 3\(d_{z^2}\) bandwidth and decrease the Ni 3\(d_{z^2}\)-O 2\(p_{z}\) hybridization, thereby suppressing the \(dd\) excitations. The evolution of spin excitations reflects significant changes in the interlayer exchange coupling \(J_z\), which can be attributed to the strain-tuned Ni-O-Ni bond angle. Since superconductivity is observed only in films with in-plane compressive strain (\(\epsilon\sim-2\%\)), the strain-dependent spin correlations align with the emergence of superconductivity, providing indirect evidence for spin-fluctuation-mediated unconventional superconductivity in LNO.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
7 pages, 4 figures. Supplementary is available upon reasonable request
Separation between long- and short-range part of the Coulomb interaction in low dimensional systems: implications for the macroscopic screening length and the collective charge excitations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-06 20:00 EST
Collective charge excitations directly probed in electron energy loss and inelastic X rays scattering spectroscopies play a key role in different fields of condensed matter physics. Being induced by the long-range part of the Coulomb interaction between particles, in standard bulk systems they appear as well-defined features in the spectra associated to the zero crossing of the real part of the macroscopic dielectric function. However, this simple criterion cannot be used to identify collective excitations in low dimensional systems where the macroscopic dielectric function is not a well defined concept. In this work, we discuss how this problem can be traced back to the definition of the long-range Coulomb interaction and we show how the appropriate separation between long- and short-range Coulomb interaction allows one to correctly express the low dimensional macroscopic dielectric function in terms of microscopic quantities accessible in first-principles calculations. This allows disentangling collective charge excitations in low dimensional materials in analogy with what one does in standard bulk systems. In addition, we show how important macroscopic quantities, such as the screening length scale, can be extracted from full first principle calculations. As an illustrative example we perform a study of the screening effects and the collective excitations in prototypical 2D materials including metals (NbSe2) as well as semiconductors (BN and MoS2).
Materials Science (cond-mat.mtrl-sci)
Perpendicular magnetic anisotropy in Au/FeCo/Au ultrathin films: Combined experimental and first-principles study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-06 20:00 EST
Justyn Snarski-Adamski, Hubert Głowiński, Justyna Rychły-Gruszecka, Piotr Kuświk, Mirosław Werwiński
Magnetic tunnel junctions with a magnetic layer with perpendicular anisotropy are currently used in computer memories that do not require voltage sustaining. An example of layers with perpendicular magnetic anisotropy are ultrathin FeCo films on Au substrate. Here, we present an experimental and computational study of Fe\(_{0.75}\)Co\(_{0.25}\) layers with a thickness up to two nanometers. The investigated FeCo layers are surrounded on both sides by Au layers. In experiment, we found perpendicular magnetic anisotropy in FeCo polycrystalline films with a thickness below 0.74 nm (five atomic monolayers). We also measured a strong surface contribution to effective magnetic anisotropy. From the density functional theory we determined structural, electronic, and magnetic properties of the FeCo films. The calculations showed an irregular dependence of magnetic anisotropy on FeCo layer thickness. We observed perpendicular anisotropy for one- and three-atom FeCo monolayers and in-plane anisotropy for two- and four-atom monolayers. However, the determination of running averages of magnetic anisotropy (of three successive thicknesses of atomic monolayers) leads to a close linear thickness dependence of magnetic anisotropy, similar to the experimental result. The reason why the properties of the several-atom-thick FeCo layers differ so significantly from those of the bulk parent material is the disappearance of the central region of the layer whose properties approximate those of the bulk, and instead the existence of near-interface regions with properties altered by the presence of discontinuities.
Materials Science (cond-mat.mtrl-sci)
From Kernels to Features: A Multi-Scale Adaptive Theory of Feature Learning
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-02-06 20:00 EST
Noa Rubin, Kirsten Fischer, Javed Lindner, David Dahmen, Inbar Seroussi, Zohar Ringel, Michael Krämer, Moritz Helias
Theoretically describing feature learning in neural networks is crucial for understanding their expressive power and inductive biases, motivating various approaches. Some approaches describe network behavior after training through a simple change in kernel scale from initialization, resulting in a generalization power comparable to a Gaussian process. Conversely, in other approaches training results in the adaptation of the kernel to the data, involving complex directional changes to the kernel. While these approaches capture different facets of network behavior, their relationship and respective strengths across scaling regimes remains an open question. This work presents a theoretical framework of multi-scale adaptive feature learning bridging these approaches. Using methods from statistical mechanics, we derive analytical expressions for network output statistics which are valid across scaling regimes and in the continuum between them. A systematic expansion of the network's probability distribution reveals that mean-field scaling requires only a saddle-point approximation, while standard scaling necessitates additional correction terms. Remarkably, we find across regimes that kernel adaptation can be reduced to an effective kernel rescaling when predicting the mean network output of a linear network. However, even in this case, the multi-scale adaptive approach captures directional feature learning effects, providing richer insights than what could be recovered from a rescaling of the kernel alone.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Machine Learning (cs.LG), Machine Learning (stat.ML)
24 pages, 6 figures
Automatic Generation of Maximally Localized Wannier Functions via Optimized Projection Functions and Self-projections
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-06 20:00 EST
Sebastian Tillack, Claudia Draxl
We present an automatized approach towards maximally localized Wannier functions (MLWFs) applicable to both occupied and unoccupied states. We overcome limitations of the standard optimized projection function (OPF) method and its approximations by providing an exact expression for the gradient of the Wannier spread functional with respect to a single semi-unitary OPF matrix. Moreover, we demonstrate that the localization of the resulting Wannier functions (WFs) can be further improved by including projections on reasonably localized WFs, so-called self-projections.
Materials Science (cond-mat.mtrl-sci)
5 pages, 3 figures, 3 tables
Nested Stochastic Resetting: Nonequilibrium Steady-states and Exact Correlations
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-02-06 20:00 EST
Henry Alston, Callum Britton, Thibault Bertrand
Stochastic resetting breaks detailed balance and drives the formation of nonequilibrium steady states . Here, we consider a chain of diffusive processes \(x_i(t)\) that interact unilaterally: at random time intervals, the process \(x_n\) stochastically resets to the instantaneous value of \(x_{n-1}\). We derive analytically the steady-state statistics of these nested stochastic resetting processes including the stationary distribution for each process as well as its moments. We are also able to calculate exactly the steady-state two-point correlations \(\langle x_n x_{n+j}\rangle\) between processes by mapping the problem to one of the ordering statistics of random counting processes. Understanding statistics and correlations in many-particle nonequilibrium systems remains a formidable challenge and our results provide an example of such tractable correlations. We expect this framework will both help build a model-independent framework for random processes with unilateral interactions and find immediate applications, e.g. in the modelling of lossy information propagation.
Statistical Mechanics (cond-mat.stat-mech)
6 pages (3 figures) of main text + 9 pages (4 figures) of supplementary information
Easy-cone state mediating the spin reorientation in topological kagome magnet Fe\(_3\)Sn\(_2\)
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-06 20:00 EST
L. Prodan, D. M. Evans, A. S. Sukhanov, S. E. Nikitin, A. A. Tsirlin, L. Puntingam, M. C. Rahn, L. Chioncel, V. Tsurkan, I. Kezsmarki
We investigated temperature-driven spin reorientation (SR) in the itinerant kagome magnet Fe\(_3\)Sn\(_2\) using high-resolution synchrotron x-ray diffraction, neutron diffraction, magnetometry, and magnetic force microscopy (MFM), further supported by phenomenological analysis. Our study reveals a crossover from the state with easy-plane anisotropy to the high-temperature state with uniaxial easy-axis anisotropy taking place between \(\sim40-130\)~ K through an intermediate easy-cone (or tilted spin) state. This state, induced by the interplay between the anisotropy constants \(K_1\) and \(K_2\), is clearly manifested in the thermal evolution of the magnetic structure factor, which reveals a gradual change of the SR angle \(\mathbf{\theta}\) between \(40-130\)~K. We also found that the SR is accompanied by a magnetoelastic effect. Zero-field MFM images across the SR range show a transformation in surface magnetic patterns from a dendritic structure at 120~K, to domain wall dominated MFM contrast at 40~K.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
24 pages, 5 figures, 75 references
Mie-enhanced micro-focused Brillouin light scattering with wavevector resolution
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-06 20:00 EST
Jakub Krčma, Ondřej Wojewoda, Martin Hrtoň, Jakub Holobrádek, Jon Ander Arregi, Jaganandha Panda, Michal Urbánek
Magnons, the quanta of spin waves, are magnetic excitations of matter spanning through the entire crystal's Brillouin zone and covering a wide range of frequencies ranging from sub-gigahertz to hundreds of terahertz. Magnons play a crucial role in many condensed matter phenomena, such as the reduction of saturation magnetization with increasing temperature or Bose-Einstein condensation. However, current experimental techniques cannot resolve magnons with wavevectors between 30 and 300\(\,\)rad\(\,\mu\)m\(^{-1}\). In this letter, we address this gap by tailoring the light in Brillouin light scattering process with dielectric periodic nanoresonators and thus gaining access to the previously unmeasurable spin waves with full wavevector resolution using table-top optical setup. Filling this gap can stimulate further experimental investigations of the fundamental phenomena associated with magnons but also stimulate the application of magnonics in computational and microwave devices. In addition, the same methodology can be applied to other excitations of matter, such as phonons, opening up new possibilities in e.g. mechanobiological studies.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Structural dependence of quantum transport properties on topological nodal-line semimetal bilayer borophene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-06 20:00 EST
C. J. Páez-González, C. E. Ardila-Gutiérrez, D. A. Bahamon
This work presents the electronic and transport properties of bilayer borophene nanoribbons. In the first part, a four-orbital tight-binding model is derived by fitting the band structure. The transport properties of armchair and zigzag bilayer borophene nanoribbons are then analyzed, both with and without periodic boundary conditions. In both scenarios, the nodal line causes conductance to increase with width and exhibit oscillations in narrow nanoribbons. Additionally, plots of current and charge density reveal that edge states have a more pronounced impact in narrower nanoribbons. Finally, uniaxial tensile strain is introduced as a tool to engineer the number of available transport channels.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Mutual control of critical temperature, RRR, stress, and surface quality for sputtered Nb films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-06 20:00 EST
E.V. Zikiy, I.A. Stepanov, S.V. Bukatin, D.A. Baklykov, M.I. Teleganov, E.A. Krivko, N.S. Smirnov, I.A. Ryzhikov, S.P. Bychkov, S.A. Kotenkov, N.D. Korshakov, J.A. Agafonova, I.A. Rodionov
Superconducting single quantum logic integrated circuits traditionally exploit magnetron sputtered niobium thin films on silicon oxide substrates. The sputtering depends on multiple process parameters, which dramatically affect mechanical, electrical, and cryogenic properties of Nb thin films. In this work, we focus on the comprehensive relationship study between 200-nm Nb film characteristics and their intrinsic stress. It is shown that there is a critical value of the working pressure pcritical at the fixed sputtering power above which stress in the film relaxes whereas the film properties degrade significantly. Below pcritical one can control intrinsic stress in the wide range from -400 MPa to +600 MPa maintaining perfect film surface with a 0.8 nm roughness (Rq), electrical resistivity less than 20 uOhm, critical superconducting transition temperature above 8.9 K and residual resistance ratio over 6.4. We suggest a modified kinetic model to predict Nb films stress with the linear dependence of high-energy parameters on the working pressure replaced with an exponential one, which allowed reduction of the approximation error from 20 to 8%.
Materials Science (cond-mat.mtrl-sci), Superconductivity (cond-mat.supr-con), Applied Physics (physics.app-ph)
First experiments with ultrashort, circularly polarized soft X-ray pulses at FLASH2
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-06 20:00 EST
S. Marotzke, D. Gupta, R.-P. Wang, M. Pavelka, S. Dziarzhytski, C. von Korff Schmising, S. Jana, N. Thielemann-Kühn, T. Amrhein, M. Weinelt, I. Vaskivskyi, R. Knut, D. Engel, M. Braune, M. Ilchen, S. Savio, T. Otto, K. Tiedtke, V. Scheppe, J. Rönsch-Schulenberg, E. Schneidmiller, C. Schüßler-Langeheine, H. A. Dürr, M. Beye, G. Brenner, N. Pontius
Time-resolved absorption spectroscopy as well as magnetic circular dichroism with circularly polarized soft X-rays (XAS and XMCD) are powerful tools to probe electronic and magnetic dynamics in magnetic materials element- and site-selectively. Employing these methods, groundbreaking results have been obtained for instance for magnetic alloys, which helped to fundamentally advance the field of ultrafast magnetization dynamics. At the free electron laser facility FLASH key capabilities for ultrafast XAS and XMCD experiments have recently improved: In an upgrade, an APPLE-III helical afterburner undulator was installed at FLASH2 in September 2023. This installation allows for the generation of circularly polarized soft X-ray pulses with a duration of a few tens of femtoseconds covering the L3,2-edges of the important 3d transition metal elements with pulse energies of several uJ. Here, we present first experimental results with such ultrashort X-ray pulses from the FL23 beamline employing XMCD at the L-edges of the 3d metals, Co, Fe and Ni. We obtain significant dichroic difference signals indicating a degree of circular polarization close to 100%. With the pulse-length preserving monochromator at beamline FL23 and an improved pump laser setup, FLASH can offer important and efficient experimental instrumentation for studies on ultrafast spin dynamics in 3d transition metals, multilayers, and alloys.
Materials Science (cond-mat.mtrl-sci)
Reversible Switching of the Environment-Protected Quantum Spin Hall Insulator Bismuthene at the Graphene/SiC Interface
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-06 20:00 EST
Niclas Tilgner, Susanne Wolff, Serguei Soubatch, Tien-Lin Lee, Andres David Peña Unigarro, Sibylle Gemming, F. Stefan Tautz, Christian Kumpf, Thomas Seyller, Fabian Göhler, Philip Schädlich
Quantum Spin Hall Insulators (QSHI) have been extensively studied both theoretically and experimentally because they exhibit robust helical edge states driven by spin-orbit coupling and offer the potential for applications in spintronics through dissipationless spin transport. However, to realize devices, it is indispensable to gain control over the interaction of the active layer with the substrate, and to protect it from environmental influences. Here we show that a single layer of elemental Bi, formed by intercalation of an epitaxial graphene buffer layer on SiC(0001), is a promising candidate for a QSHI. This layer can be reversibly switched between an electronically inactive precursor state and a ``bismuthene state'', the latter exhibiting the predicted band structure of a true two-dimensional bismuthene layer. Switching is accomplished by hydrogenation (dehydrogenation) of the sample, i.e., a partial passivation (activation) of dangling bonds of the SiC substrate, causing a lateral shift of Bi atoms involving a change of the adsorption site. In the bismuthene state, the Bi honeycomb layer is a prospective QSHI, inherently protected by the graphene sheet above and the H-passivated substrate below. Thus, our results represent an important step towards protected QSHI systems beyond graphene.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
12 pages, 3 figures, supplementary information
Electronic properties and transport in metal/2D material/metal vertical junctions
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-06 20:00 EST
Gaëlle Bigeard, Zineb Kerrami, François Triozon, Alessandro Cresti
We simulate the electronic and transport properties of metal/two-dimensional material/metal vertical heterostructures, with a focus on graphene, hexagonal boron nitride and two phases of molybdenum diselenide. Using density functional theory and non-equilibrium Green's function, we assess how stacking configurations and material thickness impact important properties, such as density of states, potential barriers and conductivity. For monolayers, strong orbital hybridization with the metallic electrodes significantly alters the electronic characteristics, with the formation of states within the gap of the semiconducting 2D materials. Trilayers reveal the critical role of interlayer coupling, where the middle layer retains its intrinsic properties, thus influencing the overall conductivity. Our findings highlight the potential for customized multilayer designs to optimize electronic device performance based on two-dimensional materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
16 pages, 6 figures
Spontaneous Twist of Ferroelectric Smectic Blocks in Polar Fluids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-06 20:00 EST
Hiroya Nishikawa, Yasushi Okumura, Dennis Kwaria, Atsuko Nihonyanagi, Fumito Araoka
In soft matter, the polar orientational order of molecules can facilitate the coexistence of structural chirality and ferroelectricity. The ferroelectric nematic (NF) state, exhibited by achiral calamitic molecules with large dipole moments, serves as an ideal model for the emergence of spontaneous structural chirality. This chiral ground state arises from a left- or right-handed twist of polarization due to depolarization effects. In contrast, the ferroelectric smectic state, characterized by a polar lamellar structure with lower symmetry, experiences significantly higher energy associated with layer-twisting deformations and the formation of domain walls, thus avoiding a continuously twisted layered structure. In this study, we develop two types of achiral molecules (BOE-NO2 and DIOLT) that possess different molecular structure but exhibit a NF-ferroelectric smectic phase sequence. We demonstrate that the chiral ground state of NF is inherited in the ferroelectric smectic phases of BOE-NO2, which features larger dipole moments and a steric hindrance moiety, thereby triggering the formation of the twisted polar smectic blocks.
Soft Condensed Matter (cond-mat.soft)
Main paper: 19 pages (5 figures); Supporting Information: 59 pages (39 figures, 3 Tables)
Revealing inter-band electron pairing in a superconductor with spin-orbit coupling
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-06 20:00 EST
Javier Zaldívar, Jon Ortuzar, Miguel Alvarado, Stefano Trivini, Julie Baumard, Carmen Rubio-Verdú, Edwin Herrera, Hermann Suderow, Alfredo Levy Yeyati, F. Sebastian Bergeret, Jose Ignacio Pascual
Most superconducting mechanisms pair electrons within the same band, forming spin singlets. However, the discovery of multi-band superconductivity has opened new scenarios for pairing, particularly in systems with strong spin-orbit coupling. Here, we reveal inter-band pairing in the superconductor by mapping the amplitude of sub-gap Yu-Shiba-Rusinov (YSR) states around Vanadium adatoms deposited on its surface. The surface of is characterized by spin-helical-like bands near the Fermi level. Scanning tunneling spectroscopy reveals anisotropic YSR amplitude oscillations around the impurity, driven by spin-conserving Bogoliubov quasiparticle interference (BQPI). Analysis of the BQPI patterns at the YSR energy exposes inter-band pairing in this material. Interestingly, only a small subset of all possible inter-band scattering processes observed in the normal state contribute to the BQPI patterns. Combining experimental data and theory, we demonstrate that the observed band selectivity results from the hybridization of the band coupled with the impurity with other bands. Our findings reveal unconventional pairing mechanisms in and highlight the crucial role of spin-orbit interactions in their formation.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
6 pages, 5 figures
Analytical solution for the polydisperse random close packing problem in 2D
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-06 20:00 EST
Mathias Casiulis, Alessio Zaccone
An analytical theory for the random close packing density, \(\phi_\textrm{RCP}\), of polydisperse hard disks is provided using a theoretical approach based on the equilibrium model of crowding [A. Zaccone, Phys. Rev. Lett. 128, 028002 (2022)], which was recently justified based on extensive numerical analysis of the maximally random jammed (MRJ) line in the hard-sphere phase diagram [Anzivino et al., J. Chem. Phys. 158, 044901 (2023)]. The solution relies on the underlying equations of state for the hard disk fluid and provides predictions of \(\phi_\textrm{RCP}\) as a function of the ratio of the standard deviation of the disk diameter distribution to its mean \(s\). For the power-law size distribution evaluated at \(s=0.246\), the theory yields \(\phi_\textrm{RCP} =0.892\), which compares well with the most recent numerical estimate \(\phi_\textrm{RCP} =0.905\) based on the Monte-Carlo swap algorithms [Ghimenti, Berthier, van Wijland, Phys. Rev. Lett. 133, 028202 (2024)].
Soft Condensed Matter (cond-mat.soft), Disordered Systems and Neural Networks (cond-mat.dis-nn), Materials Science (cond-mat.mtrl-sci), Statistical Mechanics (cond-mat.stat-mech), Chemical Physics (physics.chem-ph)
Photoemission electron microscopy of exciton-polaritons in thin WSe\(_2\) waveguides
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-06 20:00 EST
Tobias Eul, Miwan Sabir, Vector DeManuel-Gonzalez, Florian Diekmann, Kai Rossnagel, Michael Bauer
Exciton-polaritons emerging from the interaction of photons and excitons in the strong coupling regime are intriguing quasiparticles for the potential exchange of energy during light-matter interaction processes such as light harvesting. The coupling causes an energy anti-crossing in the photon dispersion centered around the exciton resonance, i.e., a Rabi splitting between a lower and upper energetic branch. The size of this splitting correlates with the coupling strength between the exciton and the photonic modes. In this work, we investigate this coupling between excitons and photonic waveguide modes excited simultaneously in thin-film flakes of the transition-metal dichalcogenide WSe\(_2\). Using a Photoemission electron microscope, we are able to extract the dispersion of the transversal electric and magnetic modes propagating through these flakes as well as extract the energy splitting. Ultimately, our findings precipitate the investigation of the propagation of exciton-polaritons in the time-domain via time-resolved photoemission.
Materials Science (cond-mat.mtrl-sci)
Fluctuation-dissipation and virtual processes in interacting phonon systems
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-06 20:00 EST
Aloïs Castellano, J. P. Alvarinhas Batista, Matthieu J. Verstraete
Phonon-phonon interactions are fundamental to understanding a wide range of material properties, including thermal transport and vibrational spectra. In conventional perturbative approaches, energy conservation during each microscopic phonon interaction is enforced using delta functions. We demonstrate that these delta functions stem from an incomplete treatment, that violates the fluctuation-dissipation theorem governing systems at equilibrium. By replacing delta functions with convolutions and introducing a self-consistency condition for the phonon spectral function, we provide a more accurate and physically consistent framework. For systems where phonon dynamics can be approximated as Markovian, we simplify this approach, reducing the dissipative component to a single parameter tied to phonon lifetimes. Applying this method to boron arsenide, we find that self-consistent linewidths better capture the phonon scattering processes, significantly improving agreement with experimental thermal conductivity values. These results also challenge the conventional view of four-phonon processes as dominant in BAs, demonstrating the adequacy of a three-phonon description, provided it is self-consistent. With this method we address critical limitations of perturbative approaches, offering new insights into dissipation and phonon-mediated processes, and enabling more accurate modeling of anharmonic materials.
Materials Science (cond-mat.mtrl-sci)
Time scale competition in the Active Coagulation Model
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-02-06 20:00 EST
Spreading processes on top of active dynamics provide a novel theoretical framework for capturing emerging collective behavior in living systems. I consider run-and-tumble dynamics coupled with coagulation/decoagulation reactions that lead to an absorbing state phase transition. While the active dynamics does not change the location of the transition point, the relaxation toward the stationary state depends on motility parameters. Because of the competition between spreading dynamics and active motion, the system can support long-living currents whose typical time scale is a nontrivial function of motility and reaction rates. Beyond the mean-field regime, instability at finite length scales regulates a crossover from periodic to diffusive modes. Finally, it is possible to individuate different mechanisms of pattern formation on a large time scale, ranging from Fisher-Kolmogorov to Kardar-Parisi-Zhang equation.
Statistical Mechanics (cond-mat.stat-mech), Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
Demagnetisation effects in single-domain particles
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-06 20:00 EST
Mathias Zambach, Miriam Varón, Mads R. Almind, Matti Knaapila, Ziwei Ouyang, Marco Beleggia, Cathrine Frandsen
According to the classical laws of magnetism, the shape of magnetically soft objects limits the effective susceptibility. For example, spherical soft magnets cannot display an effective susceptibility larger than 3. Although true for macroscopic multi-domain magnetic materials, we show that magnetic nanoparticles in a single-domain state do not suffer from this limitation. We find that the differences between demagnetisation factors along principal axes are relevant and can influence susceptibility for single-domain particles, but do not limit the susceptibility as in the case for multi-domain particles. We validate this result experimentally on spherical nanoparticles with varying diameter (8 to 150 nm) and varying volume fraction (0.1 to 47 vol%). In agreement with our predictions, we measure susceptibilities largely above 3, in fact up to more than 250, for single-domain particles. Moreover, contrary to an existing model, we find that the susceptibility of non-interacting single-domain particles in a non-magnetic matrix scales simply linearly with the volume fraction of particles.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph)
7 pages, 2 figures, 16 numbered equations. arXiv admin note: text overlap with arXiv:2308.13407
Symmetry Analysis of the Non-Hermitian Electro-Optic Effect in Crystals
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-06 20:00 EST
Sylvain Lannebère, Tatiana G. Rappoport, Tiago A. Morgado, Ivo Souza, Mário G. Silveirinha
We investigate how crystal symmetry tailors the non-Hermitian electro-optic effect driven by the Berry curvature dipole. Specifically, we demonstrate the critical influence of the material's point group symmetry and external electric biases in shaping this effect, leading to current-induced optical gain and non-reciprocal optical responses. Through a symmetry-based analysis of the crystallographic point groups, we identify how different symmetries affect the electro-optic response, enabling the engineering of polarization-dependent optical gain without the need for gyrotropic effects. In particular, we demonstrate that the non-Hermitian electro-optic response in a broad class of crystals is characterized by linear dichroic gain. In this type of response, the eigenpolarizations that activate the gain or dissipation are linearly polarized. Depending on the specific symmetry point group, it is possible to achieve gain (or dissipation) for all eigenpolarizations or to observe polarization-dependent gain and dissipation. Weyl semimetals emerge as promising candidates for realizing significant non-Hermitian electro-optic effects and linear dichroic gain. We further examine practical applications by studying the reflectance of biased materials in setups involving mirrors, demonstrating how optical gain and attenuation can be controlled via symmetry and bias configurations.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics)
14 pages, 4 figures
Room Temperature Dy Spin-Flop Switching in Strained DyFeO3 Thin Films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-06 20:00 EST
Banani Biswas, Federico Stramaglia, Ekatarina V. Pomjakushina, Thomas Lippert, Carlos A.F. Vaz, Christof W. Schneider
Epitaxial strain in thin films can yield surprising magnetic and electronic properties not accessible in bulk. One materials system destined to be explored in this direction are orthoferrites with two intertwined spin systems where strain is predicted to have a significant impact on magnetic and polar properties by modifying the strength of the rare earth-Fe interaction. Here we report the impact of epitaxial strain is reported on the linear magneto-electric DyFeO3, a canted bulk antiferromagnet with a high Neel temperature (645 K) exhibiting a Dy-induced spin reorientation transition at approx. 50 K and antiferromagnetic ordering of the Dy spins at 4 K. An increase in the spin transition of > 20 K is found and a strictly linear, abnormal temperature magnetic response under an applied magnetic field between 100 and 400 K for [010]-oriented DyFeO3 thin films with an in-plane compressive strain between 2% and 3.5%. At room temperature and above, we found that application of approx. 0.06 T causes a spin-flop of the Dy spins coupled to the antiferromagnetic Fe spin lattice, whereby the Dy spins change from an antiferromagnetic alignment to ferromagnetic. The spin-flop field gives a lower energy bound on the Dy-Fe exchange interaction of approx. 15 microeV.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
21 pages, 6 figures and supplementary information
Adv. Mater. Interfaces 2025, 2400938
Transport coefficients of a low-temperature normal Fermi gas with contact interactions: an exact perturbative expansion
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-02-06 20:00 EST
Pierre-Louis Taillat, Hadrien Kurkjian
We compute the shear viscosity, thermal conductivity and spin diffusivity of a Fermi gas with short-range interactions in the Fermi liquid regime of the normal phase, that is at temperatures \(T\) much lower than the Fermi temperature \(T_{\rm F}\) and much larger than the superfluid critical temperature \(T_c\). Given recent advances in the precision of cold atom experiments, we provide exact results up to second-order in the interaction strength. We extend the Landau-Salpeter equation to compute the collision amplitude beyond the forward-scattering limit, covering all collisions on the Fermi surface. We treat the collision kernel exactly, leading to significant corrections beyond relaxation time or variational approximations. The transport coefficients, as functions of the \(s\)-wave scattering length \(a\) and Fermi wavenumber \(k_{\rm F}\), follow \((1+\gamma k_{\rm F}a)/a^2\) up to corrections of order \(O(a^0)\), with a positive coefficient \(\gamma\) for the viscosity and negative one for the thermal conductivity and spin diffusivity. The inclusion of the correction linear in \(k_{\rm F}a\) greatly improves the agreement with the recent measurement of the viscosity by the Yale group.
Quantum Gases (cond-mat.quant-gas), Atomic Physics (physics.atom-ph), Quantum Physics (quant-ph)
8 pages, 1 figure, 1 table
Propagation of ultrashort voltage pulses through a small quantum dot
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-06 20:00 EST
The coherent transport of time-resolved ultrafast excitations in nanoelectronic interferometers is expected to exhibit an interesting interplay between the interferences and the time-dependent drive. However, the typical frequencies required to unlock this physics are in the THz range, making its observation challenging. In this work, we consider the propagation of the excitation generated by ultrashort voltage pulses through a small quantum dot, a system which we argue can display similar physics at significantly lower frequencies. We model the system with a single resonant level connected to two infinite electrodes subjected to a time-dependent voltage bias. For short pulses, we predict that the behaviour of the dot contrasts sharply with the long pulse (adiabatic) limit: the current actually oscillates with the amplitude of the voltage pulse. In the ultrafast limit, we predict that the current can even be negative, i.e. flow against the voltage drop. Our results are obtained by a combination of two approaches that are in quantitative agreement: explicit analytical expressions in the ultrafast and ultraslow limits and exact numerical simulations. We discuss the applicability of our findings and conclude that this system should be within reach of existing experimental platforms.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
12 pages, 9 figures
High temperature surface state in Kondo insulator U\(_3\)Bi\(_4\)Ni\(_3\)
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-06 20:00 EST
Christopher Broyles, Xiaohan Wan, Wenting Cheng, Dingsong Wu, Hengxin Tan, Qiaozhi Xu, Shannon L. Gould, Hasan Siddiquee, Leyan Xiao, Ryan Chen, Wanyue Lin, Yuchen Wu, Prakash Regmi, Yun Suk Eo, Jieyi Liu, Yulin Chen, Binghai Yan, Kai Sun, Sheng Ran
The resurgence of interest in Kondo insulators has been driven by two major mysteries: the presence of metallic surface states and the observation of quantum oscillations. To further explore these mysteries, it is crucial to investigate another similar system beyond the two existing ones, SmB\(_6\) and YbB\(_{12}\). Here, we address this by reporting on a Kondo insulator, U\(_3\)Bi\(_4\)Ni\(_3\). Our transport measurements reveal that a surface state emerges below 250 K and dominates transport properties below 150 K, which is well above the temperature scale of SmB\(_6\) and YbB\(_{12}\). At low temperatures, the surface conductivity is about one order of magnitude higher than the bulk. The robustness of the surface state indicates that it is inherently protected. The similarities and differences between U\(_3\)Bi\(_4\)Ni\(_3\) and the other two Kondo insulators will provide valuable insights into the nature of metallic surface states in Kondo insulators and their interplay with strong electron correlations.
Strongly Correlated Electrons (cond-mat.str-el)
Accepted to Science Advances
Unconventional anomalous Hall effect in hexagonal polar magnet Y_3Co_8Sn_4
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-06 20:00 EST
Afsar Ahmed, Jyoti Sharma, Arnab Bhattacharya, Anis Biswas, Tukai Singha, Yaroslav Mudryk, Aftab Alam, I. Das
We report a rare realization of unconventional anomalous Hall effect (UAHE) both below and above the magnetic transition temperature (T_C) in a hexagonal noncentrosymmetric magnet Y_3Co_8Sn_4, using a combined experimental and ab-initio calculations. Occurrence of such UAHE is mainly attributed to the reciprocal (KS) topology (i.e. the presence of topological Weyl points at/near the Fermi level), along with some contribution from the topological magnetic texture, as inferred from the measured field-dependent ac susceptibility. The effect of UAHE on the measured transport behavior however evolves differently with temperature above and below T_C, suggesting different physical mechanism responsible in the two phases. A unique planar ferrimagnetic ordering is found to be the most stable state with ab-plane as the easy plane below TC, as observed experimentally. The simulated net magnetization and the moment per Co atom agrees fairly well with the measured values. A reasonably large AHC is also observed in both the phases (above and below and T_C) of the present compound, which is again not so ubiquitous. Our results underscore the family of R_3Co_8Sn_4 (R= rare earth) polar magnets as a compelling backdrop for exploring the synergy of topological magnetism and non-trivial electronic bands, pivotal for spintronic applications.
Materials Science (cond-mat.mtrl-sci)