CMP Journal 2025-02-19
Statistics
Nature: 28
Nature Materials: 2
Nature Physics: 2
Nature Reviews Materials: 1
Physical Review Letters: 16
Physical Review X: 1
arXiv: 59
Nature
Mechanism for local attenuation of DNA replication at double-strand breaks
Original Paper | Double-strand DNA breaks | 2025-02-18 19:00 EST
Robin Sebastian, Eric G. Sun, Michael Fedkenheuer, Haiqing Fu, SeolKyoung Jung, Bhushan L. Thakur, Christophe E. Redon, Gianluca Pegoraro, Andy D. Tran, Jacob M. Gross, Sara Mosavarpour, Nana Afua Kusi, Anagh Ray, Anjali Dhall, Lorinc S. Pongor, Rafael Casellas, Mirit I. Aladjem
DNA double-strand breaks (DSBs) disrupt the continuity of the genome, with consequences for malignant transformation. Massive DNA damage can elicit a cellular checkpoint response that prevents cell proliferation1,2. However, how highly aggressive cancer cells, which can tolerate widespread DNA damage, respond to DSBs alongside continuous chromosome duplication is unknown. Here we show that DSBs induce a local genome maintenance mechanism that inhibits replication initiation in DSB-containing topologically associating domains (TADs) without affecting DNA synthesis at other genomic locations. This process is facilitated by mediators of replication and DSBs (MRDs). In normal and cancer cells, MRDs include the TIMELESS-TIPIN complex and the WEE1 kinase, which actively dislodges the TIMELESS-TIPIN complex from replication origins adjacent to DSBs and prevents initiation of DNA synthesis at DSB-containing TADs. Dysregulation of MRDs, or disruption of 3D chromatin architecture by dissolving TADs, results in inadvertent replication in damaged chromatin and increased DNA damage in cancer cells. We propose that the intact MRD cascade precedes DSB repair to prevent genomic instability, which is otherwise observed when replication is forced, or when genome architecture is challenged, in the presence of DSBs3,4,5. These observations reveal a previously unknown vulnerability in the DNA replication machinery that may be exploited to therapeutically target cancer cells.
Double-strand DNA breaks, Origin firing
Clonal driver neoantigen loss under EGFR TKI and immune selection pressures
Original Paper | Adaptive immunity | 2025-02-18 19:00 EST
Maise Al Bakir, James L. Reading, Samuel Gamble, Rachel Rosenthal, Imran Uddin, Andrew Rowan, Joanna Przewrocka, Amber Rogers, Yien Ning Sophia Wong, Amalie K. Bentzen, Selvaraju Veeriah, Sophia Ward, Aaron T. Garnett, Paula Kalavakur, Carlos Martínez-Ruiz, Clare Puttick, Ariana Huebner, Daniel E. Cook, David A. Moore, Chris Abbosh, Crispin T. Hiley, Cristina Naceur-Lombardelli, Thomas B. K. Watkins, Marina Petkovic, Roland F. Schwarz, Felipe Gálvez-Cancino, Kevin Litchfield, Peter Meldgaard, Boe Sandahl Sorensen, Line Bille Madsen, Dirk Jäger, Martin D. Forster, Tobias Arkenau, Clara Domingo-Vila, Timothy I. M. Tree, Mohammad Kadivar, Sine Reker Hadrup, Benny Chain, Sergio A. Quezada, Nicholas McGranahan, Charles Swanton
Neoantigen vaccines are under investigation for various cancers, including epidermal growth factor receptor (EGFR)-driven lung cancers1,2. We tracked the phylogenetic history of an EGFR mutant lung cancer treated with erlotinib, osimertinib, radiotherapy and a personalized neopeptide vaccine (NPV) targeting ten somatic mutations, including EGFR exon 19 deletion (ex19del). The ex19del mutation was clonal, but is likely to have appeared after a whole-genome doubling (WGD) event. Following osimertinib and NPV treatment, loss of the ex19del mutation was identified in a progressing small-cell-transformed liver metastasis. Circulating tumour DNA analyses tracking 467 somatic variants revealed the presence of this EGFR wild-type clone before vaccination and its expansion during osimertinib/NPV therapy. Despite systemic T cell reactivity to the vaccine-targeted ex19del neoantigen, the NPV failed to halt disease progression. The liver metastasis lost vaccine-targeted neoantigens through chromosomal instability and exhibited a hostile microenvironment, characterized by limited immune infiltration, low CXCL9 and elevated M2 macrophage levels. Neoantigens arising post-WGD were more likely to be absent in the progressing liver metastasis than those occurring pre-WGD, suggesting that prioritizing pre-WGD neoantigens may improve vaccine design. Data from the TRACERx 421 cohort3 provide evidence that pre-WGD mutations better represent clonal variants, and owing to their presence at multiple copy numbers, are less likely to be lost in metastatic transition. These data highlight the power of phylogenetic disease tracking and functional T cell profiling to understand mechanisms of immune escape during combination therapies.
Adaptive immunity, Cancer genomics, Non-small-cell lung cancer, Tumour immunology
World and Human Action Models towards gameplay ideation
Original Paper | Computer science | 2025-02-18 19:00 EST
Anssi Kanervisto, Dave Bignell, Linda Yilin Wen, Martin Grayson, Raluca Georgescu, Sergio Valcarcel Macua, Shan Zheng Tan, Tabish Rashid, Tim Pearce, Yuhan Cao, Abdelhak Lemkhenter, Chentian Jiang, Gavin Costello, Gunshi Gupta, Marko Tot, Shu Ishida, Tarun Gupta, Udit Arora, Ryen W. White, Sam Devlin, Cecily Morrison, Katja Hofmann
Generative artificial intelligence (AI) has the potential to transform creative industries through supporting human creative ideation--the generation of new ideas1,2,3,4,5. However, limitations in model capabilities raise key challenges in integrating these technologies more fully into creative practices. Iterative tweaking and divergent thinking remain key to enabling creativity support using technology6,7, yet these practices are insufficiently supported by state-of-the-art generative AI models. Using game development as a lens, we demonstrate that we can make use of an understanding of user needs to drive the development and evaluation of generative AI models in a way that aligns with these creative practices. Concretely, we introduce a state-of-the-art generative model, the World and Human Action Model (WHAM), and show that it can generate consistent and diverse gameplay sequences and persist user modifications--three capabilities that we identify as being critical for this alignment. In contrast to previous approaches to creativity support tools that required manually defining or extracting structure for relatively narrow domains, generative AI models can learn relevant structure from available data, opening the potential for a much broader range of applications.
Computer science, Culture, Interdisciplinary studies
RNA neoantigen vaccines prime long-lived CD8+ T cells in pancreatic cancer
Original Paper | Pancreatic cancer | 2025-02-18 19:00 EST
Zachary Sethna, Pablo Guasp, Charlotte Reiche, Martina Milighetti, Nicholas Ceglia, Erin Patterson, Jayon Lihm, George Payne, Olga Lyudovyk, Luis A. Rojas, Nan Pang, Akihiro Ohmoto, Masataka Amisaki, Abderezak Zebboudj, Zagaa Odgerel, Emmanuel M. Bruno, Siqi Linsey Zhang, Charlotte Cheng, Yuval Elhanati, Evelyna Derhovanessian, Luisa Manning, Felicitas Müller, Ina Rhee, Mahesh Yadav, Taha Merghoub, Jedd D. Wolchok, Olca Basturk, Mithat Gönen, Andrew S. Epstein, Parisa Momtaz, Wungki Park, Ryan Sugarman, Anna M. Varghese, Elizabeth Won, Avni Desai, Alice C. Wei, Michael I. D'Angelica, T. Peter Kingham, Kevin C. Soares, William R. Jarnagin, Jeffrey Drebin, Eileen M. O'Reilly, Ira Mellman, Ugur Sahin, Özlem Türeci, Benjamin D. Greenbaum, Vinod P. Balachandran
A fundamental challenge for cancer vaccines is to generate long-lived functional T cells that are specific for tumour antigens. Here we find that mRNA-lipoplex vaccines against somatic mutation-derived neoantigens may solve this challenge in pancreatic ductal adenocarcinoma (PDAC), a lethal cancer with few mutations. At an extended 3.2-year median follow-up from a phase 1 trial of surgery, atezolizumab (PD-L1 inhibitory antibody), autogene cevumeran1 (individualized neoantigen vaccine with backbone-optimized uridine mRNA-lipoplex nanoparticles) and modified (m) FOLFIRINOX (chemotherapy) in patients with PDAC, we find that responders with vaccine-induced T cells (n = 8) have prolonged recurrence-free survival (RFS; median not reached) compared with non-responders without vaccine-induced T cells (n = 8; median RFS 13.4 months; P = 0.007). In responders, autogene cevumeran induces CD8+ T cell clones with an average estimated lifespan of 7.7 years (range 1.5 to roughly 100 years), with approximately 20% of clones having latent multi-decade lifespans that may outlive hosts. Eighty-six percent of clones per patient persist at substantial frequencies approximately 3 years post-vaccination, including clones with high avidity to PDAC neoepitopes. Using PhenoTrack, a novel computational strategy to trace single T cell phenotypes, we uncover that vaccine-induced clones are undetectable in pre-vaccination tissues, and assume a cytotoxic, tissue-resident memory-like T cell state up to three years post-vaccination with preserved neoantigen-specific effector function. Two responders recurred and evidenced fewer vaccine-induced T cells. Furthermore, recurrent PDACs were pruned of vaccine-targeted cancer clones. Thus, in PDAC, autogene cevumeran induces de novo CD8+ T cells with multiyear longevity, substantial magnitude and durable effector functions that may delay PDAC recurrence. Adjuvant mRNA-lipoplex neoantigen vaccines may thus solve a pivotal obstacle for cancer vaccination.
Pancreatic cancer, RNA vaccines
De novo design of transmembrane fluorescence-activating proteins
Original Paper | Bioinformatics | 2025-02-18 19:00 EST
Jingyi Zhu, Mingfu Liang, Ke Sun, Yu Wei, Ruiying Guo, Lijing Zhang, Junhui Shi, Dan Ma, Qi Hu, Gaoxingyu Huang, Peilong Lu
The recognition of ligands by transmembrane proteins is essential for the exchange of materials, energy and information across biological membranes. Progress has been made in the de novo design of transmembrane proteins1,2,3,4,5,6, as well as in designing water-soluble proteins to bind small molecules7,8,9,10,11,12, but de novo design of transmembrane proteins that tightly and specifically bind to small molecules remains an outstanding challenge13. Here we present the accurate design of ligand-binding transmembrane proteins by integrating deep learning and energy-based methods. We designed pre-organized ligand-binding pockets in high-quality four-helix backbones for a fluorogenic ligand, and generated a transmembrane span using gradient-guided hallucination. The designer transmembrane proteins specifically activated fluorescence of the target fluorophore with mid-nanomolar affinity, exhibiting higher brightness and quantum yield compared to those of enhanced green fluorescent protein. These proteins were highly active in the membrane fraction of live bacterial and eukaryotic cells following expression. The crystal and cryogenic electron microscopy structures of the designer protein-ligand complexes were very close to the structures of the design models. We showed that the interactions between ligands and transmembrane proteins within the membrane can be accurately designed. Our work paves the way for the creation of new functional transmembrane proteins, with a wide range of applications including imaging, ligand sensing and membrane transport.
Bioinformatics, Membrane proteins, Protein design, Structural biology, Synthetic biology
GABAergic neuron-to-glioma synapses in diffuse midline gliomas
Original Paper | Cancer in the nervous system | 2025-02-18 19:00 EST
Tara Barron, Belgin Yalçın, Minhui Su, Youkyeong Gloria Byun, Avishai Gavish, Kiarash Shamardani, Haojun Xu, Lijun Ni, Neeraj Soni, Vilina Mehta, Samin Maleki Jahan, Yoon Seok Kim, Kathryn R. Taylor, Michael B. Keough, Michael A. Quezada, Anna C. Geraghty, Rebecca Mancusi, Linh Thuy Vo, Enrique Herrera Castañeda, Pamelyn J. Woo, Claudia K. Petritsch, Hannes Vogel, Kai Kaila, Michelle Monje
High-grade gliomas (HGGs) are the leading cause of brain cancer-related death. HGGs include clinically, anatomically and molecularly distinct subtypes that stratify into diffuse midline gliomas (DMGs), such as H3K27M-altered diffuse intrinsic pontine glioma, and hemispheric HGGs, such as IDH wild-type glioblastoma. Neuronal activity drives glioma progression through paracrine signalling1,2 and neuron-to-glioma synapses3,4,5,6. Glutamatergic AMPA receptor-dependent synapses between neurons and glioma cells have been demonstrated in paediatric3 and adult4 high-grade gliomas, and early work has suggested heterogeneous glioma GABAergic responses7. However, neuron-to-glioma synapses mediated by neurotransmitters other than glutamate remain understudied. Using whole-cell patch-clamp electrophysiology, in vivo optogenetics and patient-derived orthotopic xenograft models, we identified functional, tumour-promoting GABAergic neuron-to-glioma synapses mediated by GABAA receptors in DMGs. GABAergic input has a depolarizing effect on DMG cells due to NKCC1 chloride transporter function and consequently elevated intracellular chloride concentration in DMG malignant cells. As membrane depolarization increases glioma proliferation3,6, we found that the activity of GABAergic interneurons promotes DMG proliferation in vivo. The benzodiazepine lorazepam enhances GABA-mediated signalling, increases glioma proliferation and growth, and shortens survival in DMG patient-derived orthotopic xenograft models. By contrast, only minimal depolarizing GABAergic currents were found in hemispheric HGGs and lorazepam did not influence the growth rate of hemispheric glioblastoma xenografts. Together, these findings uncover growth-promoting GABAergic synaptic communication between GABAergic neurons and H3K27M-altered DMG cells, underscoring a tumour subtype-specific mechanism of brain cancer neurophysiology.
Cancer in the nervous system, CNS cancer
Nociceptive neurons promote gastric tumour progression via a CGRP-RAMP1 axis
Original Paper | Cancer | 2025-02-18 19:00 EST
Xiaofei Zhi, Feijing Wu, Jin Qian, Yosuke Ochiai, Guodong Lian, Ermanno Malagola, Biyun Zheng, Ruhong Tu, Yi Zeng, Hiroki Kobayashi, Zhangchuan Xia, Ruizhi Wang, Yueqing Peng, Qiongyu Shi, Duan Chen, Sandra W. Ryeom, Timothy C. Wang
Cancer cells have been shown to exploit neurons to modulate their survival and growth, including through the establishment of neural circuits within the central nervous system1,2,3. Here we report a distinct pattern of cancer-nerve interactions between the peripheral nervous system and gastric cancer. In multiple mouse models of gastric cancer, nociceptive nerves demonstrated the greatest degree of nerve expansion in an NGF-dependent manner. Neural tracing identified CGRP+ peptidergic neurons as the primary gastric sensory neurons. Three-dimensional co-culture models showed that sensory neurons directly connect with gastric cancer spheroids. Chemogenetic activation of sensory neurons induced the release of calcium into the cytoplasm of cancer cells, promoting tumour growth and metastasis. Pharmacological ablation of sensory neurons or treatment with CGRP inhibitors suppressed tumour growth and extended survival. Depolarization of gastric tumour membranes through in vivo optogenetic activation led to enhanced calcium flux in jugular nucleus complex and CGRP release, defining a cancer cell-peptidergic neuronal circuit. Together, these findings establish the functional connectivity between cancer and sensory neurons, identifying this pathway as a potential therapeutic target.
Cancer, Gastric cancer
Thermal Ca2+/Mg2+ exchange reactions to synthesize CO2 removal materials
Original Paper | Carbon capture and storage | 2025-02-18 19:00 EST
Yuxuan Chen, Matthew W. Kanan
Most current strategies for carbon management require CO2 removal (CDR) from the atmosphere on the multi-hundred gigatonne (Gt) scale by 2100 (refs. 1,2,3,4,5). Mg-rich silicate minerals can remove >105 Gt CO2 and sequester it as stable and innocuous carbonate minerals or dissolved bicarbonate ions3,6,7. However, the reaction rates of these minerals under ambient conditions are far too slow for practical use. Here we show that CaCO3 and CaSO4 react quantitatively with diverse Mg-rich silicates (for example, olivine, serpentine and augite) under thermochemical conditions to form Ca2SiO4 and MgO. On exposure to ambient air under wet conditions, Ca2SiO4 is converted to CaCO3 and silicic acid, and MgO is partially converted into a Mg carbonate within weeks, whereas the input Mg silicate shows no reactivity over 6 months. Alternatively, Ca2SiO4 and MgO can be completely carbonated to CaCO3 and Mg(HCO3)2 under 1 atm CO2 at ambient temperature within hours. Using CaCO3 as the Ca source, this chemistry enables a CDR process in which the output Ca2SiO4/MgO material is used to remove CO2 from air or soil and the CO2 process emissions are sequestered. Analysis of the energy requirements indicates that this process could require less than 1 MWh per tonne CO2 removed, approximately half the energy of CO2 capture with leading direct air capture technologies. The chemistry described here could unlock Mg-rich silicates as a vast resource for safe and permanent CDR.
Carbon capture and storage, Chemistry
Modulated ringdown comb interferometry for sensing of highly complex gases
Original Paper | Frequency combs | 2025-02-18 19:00 EST
Qizhong Liang, Apoorva Bisht, Andrew Scheck, Peter G. Schunemann, Jun Ye
Gas samples relevant to health1,2,3 and the environment4,5,6 typically contain many molecular species that span a huge concentration dynamic range. Mid-infrared frequency comb spectroscopy with high-finesse cavity enhancement has allowed the most sensitive multispecies trace-gas detections so far2,7,8,9,10,11,12,13. However, the robust performance of this technique depends critically on ensuring absorption-path-length enhancement over a broad spectral coverage, which is severely limited by comb-cavity frequency mismatch if strongly absorbing compounds are present. Here we introduce modulated ringdown comb interferometry, a technique that resolves the vulnerability of comb-cavity enhancement to strong intracavity absorption or dispersion. This technique works by measuring ringdown dynamics carried by massively parallel comb lines transmitted through a length-modulated cavity, making use of both the periodicity of the field dynamics and the Doppler frequency shifts introduced from a Michelson interferometer. As a demonstration, we measure highly dispersive exhaled human breath samples and ambient air in the mid-infrared with finesse improved to 23,000 and coverage to 1,010 cm-1. Such a product of finesse and spectral coverage is orders of magnitude better than all previous demonstrations2,7,8,9,10,11,12,13,14,15,16,17,18,19,20, enabling us to simultaneously quantify 20 distinct molecular species at above 1-part-per-trillion sensitivity varying in concentrations by seven orders of magnitude. This technique unlocks next-generation sensing performance for complex and dynamic molecular compositions, with scalable improvement to both finesse and spectral coverage.
Frequency combs, Infrared spectroscopy
Perovskite heteroepitaxy for high-efficiency and stable pure-red LEDs
Original Paper | Lasers, LEDs and light sources | 2025-02-18 19:00 EST
Keyu Wei, Tong Zhou, Yuanzhi Jiang, Changjiu Sun, Yulong Liu, Saisai Li, Siyu Liu, Xinliang Fu, Cejun Hu, Shun Tian, Yingguo Yang, Xuewen Fu, Najla AlMasoud, Saif M. H. Qaid, Mohammad Khaja Nazeeruddin, Hsien-Yi Hsu, Wen-Di Li, Ji Tae Kim, Run Long, Wei Zhang, Jun Chen, Mingjian Yuan
Ultrasmall CsPbI3 perovskite quantum dots (QDs) are the most promising candidates for realizing efficient and stable pure-red perovskite light-emitting diodes (PeLEDs)1,2,3,4,5. However, it is challenging for ultrasmall CsPbI3 QDs to retain their solution-phase properties when they assemble into conductive films, greatly hindering their device application3,6. Here we report an approach for in situ deposit stabilized ultrasmall CsPbI3 QD conductive solids, by constructing CsPbI3 QD/quasi-two-dimensional (quasi-2D) perovskite heteroepitaxy. The well-aligned periodic array of edge-oriented ligands at heterointerface triggers a substantial octahedral tilting in a critical layer thickness of CsPbI3 QDs, which heightens the Gibbs free energy difference between the tilted-CsPbI3 and δ-CsPbI3 leading to thermodynamic stabilization of CsPbI3 QDs. The approach allows us to fabricate stabilized CsPbI3 QD conductive films with tunable emission covering the entire red spectral region from 600 nm to 710 nm. Here we report the pure-red PeLEDs with narrow electroluminescence peak centred at 630 nm, matching the Rec. 2100 standard for ultrahigh-definition display. The champion device exhibits a certified external quantum efficiency of 24.6% and a half-lifetime of 6,330 min, ranking as one of the most efficient and stable pure-red PeLED reported to date. The approach is also compatible with large-area manufacturing, enabling 1 cm2 PeLED to exhibit the best external quantum efficiency of 20.5% at 630 nm.
Lasers, LEDs and light sources, Materials for devices
Global modules robustly emerge from local interactions and smooth gradients
Original Paper | Biological physics | 2025-02-18 19:00 EST
Mikail Khona, Sarthak Chandra, Ila Fiete
Modular structure and function are ubiquitous in biology, from the organization of animal brains and bodies to the scale of ecosystems. However, the mechanisms of modularity emergence from non-modular precursors remain unclear. Here we introduce the principle of peak selection, a process by which purely local interactions and smooth gradients can drive the self-organization of discrete global modules. The process combines strengths of the positional and Turing pattern-formation mechanisms into a model for morphogenesis. Applied to the grid-cell system of the brain, peak selection results in the self-organization of functionally distinct modules with discretely spaced spatial periods. Applied to ecological systems, it results in discrete multispecies niches and synchronous spawning across geographically distributed coral colonies. The process exhibits self-scaling with system size and ‘topological robustness'1, which renders module emergence and module properties insensitive to most parameters. Peak selection ameliorates the fine-tuning requirement for continuous attractor dynamics in single grid-cell modules and it makes a detail-independent prediction that grid module period ratios should approximate adjacent integer ratios, providing a highly accurate match to the available data. Predictions for grid cells at the transcriptional, connectomic and physiological levels promise to elucidate the interplay of molecules, connectivity and function emergence in brains.
Biological physics, Network models, Neural circuits, Theoretical ecology
SPO11 dimers are sufficient to catalyse DNA double-strand breaks in vitro
Original Paper | Double-strand DNA breaks | 2025-02-18 19:00 EST
Cédric Oger, Corentin Claeys Bouuaert
SPO11 initiates meiotic recombination through the induction of programmed DNA double-strand breaks (DSBs)1,2, but this catalytic activity has never been reconstituted in vitro3,4. Here, using Mus musculus SPO11, we report a biochemical system that recapitulates all the hallmarks of meiotic DSB formation. We show that SPO11 catalyses break formation in the absence of any partners and remains covalently attached to the 5' broken strands. We find that target site selection by SPO11 is influenced by the sequence, bendability and topology of the DNA substrate, and provide evidence that SPO11 can reseal single-strand DNA breaks. In addition, we show that SPO11 is monomeric in solution and that cleavage requires dimerization for the reconstitution of two hybrid active sites. SPO11 and its partner TOP6BL form a 1:1 complex that catalyses DNA cleavage with an activity similar to that of SPO11 alone. However, this complex binds DNA ends with higher affinity, suggesting a potential role after cleavage. We propose a model in which additional partners of SPO11 required for DSB formation in vivo assemble biomolecular condensates that recruit SPO11-TOP6BL, enabling dimerization and cleavage. Our work establishes SPO11 dimerization as the fundamental mechanism that controls the induction of meiotic DSBs.
Double-strand DNA breaks, Enzyme mechanisms, Meiosis
Interferometric single-shot parity measurement in InAs-Al hybrid devices
Original Paper | Qubits | 2025-02-18 19:00 EST
Morteza Aghaee, Alejandro Alcaraz Ramirez, Zulfi Alam, Rizwan Ali, Mariusz Andrzejczuk, Andrey Antipov, Mikhail Astafev, Amin Barzegar, Bela Bauer, Jonathan Becker, Umesh Kumar Bhaskar, Alex Bocharov, Srini Boddapati, David Bohn, Jouri Bommer, Leo Bourdet, Arnaud Bousquet, Samuel Boutin, Lucas Casparis, Benjamin J. Chapman, Sohail Chatoor, Anna Wulff Christensen, Cassandra Chua, Patrick Codd, William Cole, Paul Cooper, Fabiano Corsetti, Ajuan Cui, Paolo Dalpasso, Juan Pablo Dehollain, Gijs de Lange, Michiel de Moor, Andreas Ekefjärd, Tareq El Dandachi, Juan Carlos Estrada Saldaña, Saeed Fallahi, Luca Galletti, Geoff Gardner, Deshan Govender, Flavio Griggio, Ruben Grigoryan, Sebastian Grijalva, Sergei Gronin, Jan Gukelberger, Marzie Hamdast, Firas Hamze, Esben Bork Hansen, Sebastian Heedt, Zahra Heidarnia, Jesús Herranz Zamorano, Samantha Ho, Laurens Holgaard, John Hornibrook, Jinnapat Indrapiromkul, Henrik Ingerslev, Lovro Ivancevic, Thomas Jensen, Jaspreet Jhoja, Jeffrey Jones, Konstantin V. Kalashnikov, Ray Kallaher, Rachpon Kalra, Farhad Karimi, Torsten Karzig, Evelyn King, Maren Elisabeth Kloster, Christina Knapp, Dariusz Kocon, Jonne V. Koski, Pasi Kostamo, Mahesh Kumar, Tom Laeven, Thorvald Larsen, Jason Lee, Kyunghoon Lee, Grant Leum, Kongyi Li, Tyler Lindemann, Matthew Looij, Julie Love, Marijn Lucas, Roman Lutchyn, Morten Hannibal Madsen, Nash Madulid, Albert Malmros, Michael Manfra, Devashish Mantri, Signe Brynold Markussen, Esteban Martinez, Marco Mattila, Robert McNeil, Antonio B. Mei, Ryan V. Mishmash, Gopakumar Mohandas, Christian Mollgaard, Trevor Morgan, George Moussa, Chetan Nayak, Jens Hedegaard Nielsen, Jens Munk Nielsen, William Hvidtfelt Padkar Nielsen, Bas Nijholt, Mike Nystrom, Eoin O'Farrell, Thomas Ohki, Keita Otani, Brian Paquelet Wütz, Sebastian Pauka, Karl Petersson, Luca Petit, Dima Pikulin, Guen Prawiroatmodjo, Frank Preiss, Eduardo Puchol Morejon, Mohana Rajpalke, Craig Ranta, Katrine Rasmussen, David Razmadze, Outi Reentila, David J. Reilly, Yuan Ren, Ken Reneris, Richard Rouse, Ivan Sadovskyy, Lauri Sainiemi, Irene Sanlorenzo, Emma Schmidgall, Cristina Sfiligoj, Mustafeez Bashir Shah, Kevin Simoes, Shilpi Singh, Sarat Sinha, Thomas Soerensen, Patrick Sohr, Tomas Stankevic, Lieuwe Stek, Eric Stuppard, Henri Suominen, Judith Suter, Sam Teicher, Nivetha Thiyagarajah, Raj Tholapi, Mason Thomas, Emily Toomey, Josh Tracy, Michelle Turley, Shivendra Upadhyay, Ivan Urban, Kevin Van Hoogdalem, David J. Van Woerkom, Dmitrii V. Viazmitinov, Dominik Vogel, John Watson, Alex Webster, Joseph Weston, Georg W. Winkler, Di Xu, Chung Kai Yang, Emrah Yucelen, Roland Zeisel, Guoji Zheng, Justin Zilke
The fusion of non-Abelian anyons is a fundamental operation in measurement-only topological quantum computation1. In one-dimensional topological superconductors (1DTSs)2,3,4, fusion amounts to a determination of the shared fermion parity of Majorana zero modes (MZMs). Here we introduce a device architecture5 that is compatible with future tests of fusion rules. We implement a single-shot interferometric measurement of fermion parity6,7,8,9,10,11 in indium arsenide-aluminium heterostructures with a gate-defined superconducting nanowire12,13,14. The interferometer is formed by tunnel-coupling the proximitized nanowire to quantum dots. The nanowire causes a state-dependent shift of the quantum capacitance of these quantum dots of up to 1 fF. Our quantum-capacitance measurements show flux h/2e-periodic bimodality with a signal-to-noise ratio (SNR) of 1 in 3.6 μs at optimal flux values. From the time traces of the quantum-capacitance measurements, we extract a dwell time in the two associated states that is longer than 1 ms at in-plane magnetic fields of approximately 2 T. We discuss the interpretation of our measurements in terms of both topologically trivial and non-trivial origins. The large capacitance shift and long poisoning time enable a parity measurement with an assignment error probability of 1%.
Qubits, Topological matter
In vitro reconstitution of meiotic DNA double-strand-break formation
Original Paper | Double-strand DNA breaks | 2025-02-18 19:00 EST
Xinzhe Tang, Zetao Hu, Jian Ding, Meixia Wu, Pin Guan, Yawei Song, Yue Yin, Wei Wu, Jinbiao Ma, Ying Huang, Ming-Han Tong
The Spo11 complex catalyses the formation of DNA double-strand breaks (DSBs), initiating meiotic recombination--a process that is essential for fertility and genetic diversity1,2. Although the function of Spo11 has been known for 27 years, previous efforts to reconstitute DSB formation in vitro have been unsuccessful. Here we biochemically characterize the mouse SPO11-TOP6BL protein complex, and show that this complex cleaves DNA and covalently attaches to the 5' terminus of DNA breaks in vitro. Using a point-mutation strategy, we reveal that Mg2+ is essential for the DNA-cleavage activity of this complex in vitro, as confirmed by knock-in mice carrying a point mutation in SPO11 that disrupts its binding to Mg2+, thereby abolishing DSB formation. However, the activity of the SPO11 complex is ATP-independent. We also present evidence that the mouse SPO11 complex is biochemically distinct from the ancestral topoisomerase VI. Our findings establish a mechanistic framework for understanding the first steps of meiotic recombination.
Double-strand DNA breaks, Enzyme mechanisms, Meiosis
Reconstitution of SPO11-dependent double-strand break formation
Original Paper | DNA recombination | 2025-02-18 19:00 EST
Zhi Zheng, Lyuqin Zheng, Meret Arter, Kaixian Liu, Shintaro Yamada, David Ontoso, Soonjoung Kim, Scott Keeney
Meiotic recombination starts with SPO11 generation of DNA double-strand breaks (DSBs)1. SPO11 is critical for meiosis in most species, but it generates dangerous DSBs with mutagenic2 and gametocidal3 potential. Cells must therefore utilize the beneficial functions of SPO11 while minimizing its risks4--how they do so remains poorly understood. Here we report reconstitution of DNA cleavage in vitro with purified recombinant mouse SPO11 bound to TOP6BL. SPO11-TOP6BL complexes are monomeric (1:1) in solution and bind tightly to DNA, but dimeric (2:2) assemblies cleave DNA to form covalent 5' attachments that require SPO11 active-site residues, divalent metal ions and SPO11 dimerization. SPO11 can also reseal DNA that it has nicked. Structure modelling with AlphaFold 3 suggests that DNA is bent prior to cleavage5. In vitro cleavage displays a sequence bias that partially explains DSB site preferences in vivo. Cleavage is inefficient on complex DNA substrates, partly because SPO11 is readily trapped in DSB-incompetent (presumably monomeric) binding states that exchange slowly. However, cleavage is improved with substrates that favour dimer assembly or by artificially dimerizing SPO11. Our results inform a model in which intrinsically weak dimerization restrains SPO11 activity in vivo, making it exquisitely dependent on accessory proteins that focus and control DSB formation.
DNA recombination, Double-strand DNA breaks, Enzyme mechanisms, Meiosis
Scale dichotomization reduces customer racial discrimination and income inequality
Original Paper | Human behaviour | 2025-02-18 19:00 EST
Tristan L. Botelho, Sora Jun, Demetrius Humes, Katherine A. DeCelles
Online platforms are rife with racial discrimination1, but current interventions focus on employers2,3 rather than customers. We propose a customer-facing solution: changing to a two-point rating scale (dichotomization). Compared with the ubiquitous five-star scale, we argue that dichotomization reduces modern racial discrimination by focusing evaluators on the distinction between ‘good' and ‘bad' performance, thereby reducing how personal beliefs shape customer assessments. Study 1 is a quasi-natural experiment on a home-services labour platform (n = 69,971) in which the company exogenously changed from a five-star scale to a dichotomous scale (thumbs up or thumbs down). Dichotomization eliminated customers' racial discrimination whereby non-white workers received lower ratings and earned 91 cents for each US dollar paid to white workers for the same work. A pre-registered experiment (study 2, n = 652) found that the equalizing effect of dichotomization is most prevalent among evaluators holding modern racist beliefs. Further experiments (study 3, n = 1,435; study 4, n = 528) provide evidence of the proposed mechanism, and eight supplementary studies support measurement and design choices. Our research offers a promising intervention for reducing customers' subtle racial discrimination in a large section of the economy and contributes to the interdisciplinary literature on evaluation processes and racial inequality.
Human behaviour, Sociology
Hypotaxy of wafer-scale single-crystal transition metal dichalcogenides
Original Paper | Materials science | 2025-02-18 19:00 EST
Donghoon Moon, Wonsik Lee, Chaesung Lim, Jinwoo Kim, Jiwoo Kim, Yeonjoon Jung, Hyun-Young Choi, Won Seok Choi, Hangyel Kim, Ji-Hwan Baek, Changheon Kim, Jaewoong Joo, Hyun-Geun Oh, Hajung Jang, Kenji Watanabe, Takashi Taniguchi, Sukang Bae, Jangyup Son, Huije Ryu, Junyoung Kwon, Hyeonsik Cheong, Jeong Woo Han, Hyejin Jang, Gwan-Hyoung Lee
Two-dimensional (2D) semiconductors, particularly transition metal dichalcogenides (TMDs), are promising for advanced electronics beyond silicon1,2,3. Traditionally, TMDs are epitaxially grown on crystalline substrates by chemical vapour deposition. However, this approach requires post-growth transfer to target substrates, which makes controlling thickness and scalability difficult. Here we introduce a method called hypotaxy (‘hypo' meaning downward and ‘taxy' meaning arrangement), which enables wafer-scale single-crystal TMD growth directly on various substrates, including amorphous and lattice-mismatched substrates, while preserving crystalline alignment with an overlying 2D template. By sulfurizing or selenizing a pre-deposited metal film under graphene, aligned TMD nuclei form, coalescing into a single-crystal film as graphene is removed. This method achieves precise MoS2 thickness control from monolayer to hundreds of layers on diverse substrates, producing 4-inch single-crystal MoS2 with high thermal conductivity (about 120 W m-1 K-1) and mobility (around 87 cm2 V-1 s-1). Furthermore, nanopores created in graphene using oxygen plasma treatment allow MoS2 growth at a lower temperature of 400 °C, compatible with back-end-of-line processes. This hypotaxy approach extends to other TMDs, such as MoSe2, WS2 and WSe2, offering a solution to substrate limitations in conventional epitaxy and enabling wafer-scale TMDs for monolithic three-dimensional integration.
Materials science, Nanoscale materials, Synthesis and processing, Two-dimensional materials
An opponent striatal circuit for distributional reinforcement learning
Original Paper | Computational neuroscience | 2025-02-18 19:00 EST
Adam S. Lowet, Qiao Zheng, Melissa Meng, Sara Matias, Jan Drugowitsch, Naoshige Uchida
Machine learning research has achieved large performance gains on a wide range of tasks by expanding the learning target from mean rewards to entire probability distributions of rewards--an approach known as distributional reinforcement learning (RL)1. The mesolimbic dopamine system is thought to underlie RL in the mammalian brain by updating a representation of mean value in the striatum2, but little is known about whether, where and how neurons in this circuit encode information about higher-order moments of reward distributions3. Here, to fill this gap, we used high-density probes (Neuropixels) to record striatal activity from mice performing a classical conditioning task in which reward mean, reward variance and stimulus identity were independently manipulated. In contrast to traditional RL accounts, we found robust evidence for abstract encoding of variance in the striatum. Chronic ablation of dopamine inputs disorganized these distributional representations in the striatum without interfering with mean value coding. Two-photon calcium imaging and optogenetics revealed that the two major classes of striatal medium spiny neurons--D1 and D2--contributed to this code by preferentially encoding the right and left tails of the reward distribution, respectively. We synthesize these findings into a new model of the striatum and mesolimbic dopamine that harnesses the opponency between D1 and D2 medium spiny neurons4,5,6,7,8,9 to reap the computational benefits of distributional RL.
Computational neuroscience, Motivation, Reward
Human-correlated genetic models identify precision therapy for liver cancer
Original Paper | Genetic engineering | 2025-02-18 19:00 EST
Miryam Müller, Stephanie May, Holly Hall, Timothy J. Kendall, Lynn McGarry, Lauriane Blukacz, Sandro Nuciforo, Anastasia Georgakopoulou, Thomas Jamieson, Narisa Phinichkusolchit, Sandeep Dhayade, Toshiyasu Suzuki, Júlia Huguet-Pradell, Ian R. Powley, Leah Officer-Jones, Rachel L. Pennie, Roger Esteban-Fabró, Albert Gris-Oliver, Roser Pinyol, George L. Skalka, Jack Leslie, Matthew Hoare, Joep Sprangers, Gaurav Malviya, Agata Mackintosh, Emma Johnson, Misti McCain, John Halpin, Christos Kiourtis, Colin Nixon, Graeme Clark, William Clark, Robin Shaw, Ann Hedley, Thomas M. Drake, Ee Hong Tan, Matt Neilson, Daniel J. Murphy, David Y. Lewis, Helen L. Reeves, John Le Quesne, Derek A. Mann, Leo M. Carlin, Karen Blyth, Josep M. Llovet, Markus H. Heim, Owen J. Sansom, Crispin J. Miller, Thomas G. Bird
Hepatocellular carcinoma (HCC), the most common form of primary liver cancer, is a leading cause of cancer-related mortality worldwide1,2. HCC occurs typically from a background of chronic liver disease, caused by a spectrum of predisposing conditions. Tumour development is driven by the expansion of clones that accumulate progressive driver mutations3, with hepatocytes the most likely cell of origin2. However, the landscape of driver mutations in HCC is broadly independent of the underlying aetiologies4. Despite an increasing range of systemic treatment options for advanced HCC, outcomes remain heterogeneous and typically poor. Emerging data suggest that drug efficacies depend on disease aetiology and genetic alterations5,6. Exploring subtypes in preclinical models with human relevance will therefore be essential to advance precision medicine in HCC7. Here we generated a suite of genetically driven immunocompetent in vivo and matched in vitro HCC models. Our models represent multiple features of human HCC, including clonal origin, histopathological appearance and metastasis. We integrated transcriptomic data from the mouse models with human HCC data and identified four common human-mouse subtype clusters. The subtype clusters had distinct transcriptomic characteristics that aligned with the human histopathology. In a proof-of-principle analysis, we verified response to standard-of-care treatment and used a linked in vitro-in vivo pipeline to identify a promising therapeutic candidate, cladribine, that has not previously been linked to HCC treatment. Cladribine acts in a highly effective subtype-specific manner in combination with standard-of-care therapy.
Genetic engineering, Immunotherapy, Liver cancer, Predictive markers
Spontaneous ordering of identical materials into a triboelectric series
Original Paper | Physics | 2025-02-18 19:00 EST
Juan Carlos Sobarzo, Felix Pertl, Daniel M. Balazs, Tommaso Costanzo, Markus Sauer, Annette Foelske, Markus Ostermann, Christian M. Pichler, Yongkang Wang, Yuki Nagata, Mischa Bonn, Scott Waitukaitis
When two insulating, neutral materials are contacted and separated, they exchange electrical charge1. Experiments have long suggested that this ‘contact electrification' is transitive, with different materials ordering into ‘triboelectric series' based on the sign of charge acquired2. At the same time, the effect is plagued by unpredictability, preventing consensus on the mechanism and casting doubt on the rhyme and reason that series imply3. Here we expose an unanticipated connection between the unpredictability and order in contact electrification: nominally identical materials initially exchange charge randomly and intransitively, but--over repeated experiments--order into triboelectric series. We find that this evolution is driven by the act of contact itself--samples with more contacts in their history charge negatively to ones with fewer contacts. Capturing this ‘contact bias' in a minimal model, we recreate both the initial randomness and ultimate order in numerical simulations and use it experimentally to force the appearance of a triboelectric series of our choosing. With a set of surface-sensitive techniques to search for the underlying alterations contact creates, we only find evidence of nanoscale morphological changes, pointing to a mechanism strongly coupled with mechanics. Our results highlight the centrality of contact history in contact electrification and suggest that focusing on the unpredictability that has long plagued the effect may hold the key to understanding it.
Physics, Soft materials
Cooperative nutrient scavenging is an evolutionary advantage in cancer
Original Paper | Cancer metabolism | 2025-02-18 19:00 EST
Gizem Guzelsoy, Setiembre D. Elorza, Manon Ros, Logan T. Schachtner, Makiko Hayashi, Spencer Hobson-Gutierrez, Parker Rundstrom, Julia S. Brunner, Ray Pillai, William E. Walkowicz, Lydia W. S. Finley, Maxime Deforet, Thales Papagiannakopoulos, Carlos Carmona-Fontaine
The survival of malignant cells within tumours is often seen as depending on ruthless competition for nutrients and other resources1,2. Although competition is certainly critical for tumour evolution and cancer progression, cooperative interactions within tumours are also important, albeit poorly understood3,4. Cooperative populations at all levels of biological organization risk extinction if their population size falls below a critical tipping point5,6. Here we examined whether cooperation among tumour cells may be a potential therapeutic target. We identified a cooperative mechanism that enables tumour cells to proliferate under the amino acid-deprived conditions found in the tumour microenvironment. Disruption of this mechanism drove cultured tumour populations to the critical extinction point and resulted in a marked reduction in tumour growth in vivo. Mechanistically, we show that tumour cells collectively digest extracellular oligopeptides through the secretion of aminopeptidases. The resulting free amino acids benefit both aminopeptidase-secreting cells and neighbouring cells. We identified CNDP2 as the key enzyme that hydrolyses these peptides extracellularly, and loss of this aminopeptidase prevents tumour growth in vitro and in vivo. These data show that cooperative scavenging of nutrients is key to survival in the tumour microenvironment and reveal a targetable cancer vulnerability.
Cancer metabolism, Cancer microenvironment
Dual regulation of mitochondrial fusion by Parkin-PINK1 and OMA1
Original Paper | Genetic interaction | 2025-02-18 19:00 EST
Tatsuya Yamada, Arisa Ikeda, Daisuke Murata, Hu Wang, Cissy Zhang, Pratik Khare, Yoshihiro Adachi, Fumiya Ito, Pedro M. Quirós, Seth Blackshaw, Carlos López-Otín, Thomas Langer, David C. Chan, Anne Le, Valina L. Dawson, Ted M. Dawson, Miho Iijima, Hiromi Sesaki
Mitochondrial stress pathways protect mitochondrial health from cellular insults1,2,3,4,5,6,7,8. However, their role under physiological conditions is largely unknown. Here, using 18 single, double and triple whole-body and tissue-specific knockout and mutant mice, along with systematic mitochondrial morphology analysis, untargeted metabolomics and RNA sequencing, we discovered that the synergy between two stress-responsive systems--the ubiquitin E3 ligase Parkin and the metalloprotease OMA1--safeguards mitochondrial structure and genome by mitochondrial fusion, mediated by the outer membrane GTPase MFN1 and the inner membrane GTPase OPA1. Whereas the individual loss of Parkin or OMA1 does not affect mitochondrial integrity, their combined loss results in small body size, low locomotor activity, premature death, mitochondrial abnormalities and innate immune responses. Thus, our data show that Parkin and OMA1 maintain a dual regulatory mechanism that controls mitochondrial fusion at the two membranes, even in the absence of extrinsic stress.
Genetic interaction, Mechanisms of disease, Mitochondria, Mitophagy
Tumour-wide RNA splicing aberrations generate actionable public neoantigens
Original Paper | Cancer immunotherapy | 2025-02-18 19:00 EST
Darwin W. Kwok, Nicholas O. Stevers, Iñaki Etxeberria, Takahide Nejo, Maggie Colton Cove, Lee H. Chen, Jangham Jung, Kaori Okada, Senthilnath Lakshmanachetty, Marco Gallus, Abhilash Barpanda, Chibo Hong, Gary K. L. Chan, Jerry Liu, Samuel H. Wu, Emilio Ramos, Akane Yamamichi, Payal B. Watchmaker, Hirokazu Ogino, Atsuro Saijo, Aidan Du, Nadia R. Grishanina, James Woo, Aaron Diaz, Shawn L. Hervey-Jumper, Susan M. Chang, Joanna J. Phillips, Arun P. Wiita, Christopher A. Klebanoff, Joseph F. Costello, Hideho Okada
T cell-based immunotherapies hold promise in treating cancer by leveraging the immune system's recognition of cancer-specific antigens1. However, their efficacy is limited in tumours with few somatic mutations and substantial intratumoural heterogeneity2,3,4. Here we introduce a previously uncharacterized class of tumour-wide public neoantigens originating from RNA splicing aberrations in diverse cancer types. We identified T cell receptor clones capable of recognizing and targeting neoantigens derived from aberrant splicing in GNAS and RPL22. In cases with multi-site biopsies, we detected the tumour-wide expression of the GNAS neojunction in glioma, mesothelioma, prostate cancer and liver cancer. These neoantigens are endogenously generated and presented by tumour cells under physiologic conditions and are sufficient to trigger cancer cell eradication by neoantigen-specific CD8+ T cells. Moreover, our study highlights a role for dysregulated splicing factor expression in specific cancer types, leading to recurrent patterns of neojunction upregulation. These findings establish a molecular basis for T cell-based immunotherapies addressing the challenges of intratumoural heterogeneity.
Cancer immunotherapy, CNS cancer, MHC class I, Translational immunology, Tumour heterogeneity
A dual-pathway architecture for stress to disrupt agency and promote habit
Original Paper | Neural circuits | 2025-02-18 19:00 EST
Jacqueline R. Giovanniello, Natalie Paredes, Anna Wiener, Kathia Ramírez-Armenta, Chukwuebuka Oragwam, Hanniel O. Uwadia, Abigail L. Yu, Kayla Lim, Jenna S. Pimenta, Gabriela E. Vilchez, Gift Nnamdi, Alicia Wang, Megha Sehgal, Fernando MCV Reis, Ana C. Sias, Alcino J. Silva, Avishek Adhikari, Melissa Malvaez, Kate M. Wassum
Chronic stress can change how we learn and, thus, how we make decisions1,2,3,4,5. Here we investigated the neuronal circuit mechanisms that enable this. Using a multifaceted systems neuroscience approach in male and female mice, we reveal a dual-pathway, amygdala-striatal neuronal circuit architecture by which a recent history of chronic stress disrupts the action-outcome learning underlying adaptive agency and promotes the formation of inflexible habits. We found that the projection from the basolateral amygdala to the dorsomedial striatum is activated by rewarding events to support the action-outcome learning needed for flexible, goal-directed decision-making. Chronic stress attenuates this to disrupt action-outcome learning and, therefore, agency. Conversely, the projection from the central amygdala to the dorsomedial striatum mediates habit formation. Following stress, this pathway is progressively recruited to learning to promote the premature formation of inflexible habits. Thus, stress exerts opposing effects on two amygdala-striatal pathways to disrupt agency and promote habit. These data provide neuronal circuit insights into how chronic stress shapes learning and decision-making, and help understanding of how stress can lead to the disrupted decision-making and pathological habits that characterize substance use disorders and mental health conditions.
Neural circuits, Operant learning, Stress and resilience
Plasmodium blood stage development requires the chromatin remodeller Snf2L
Original Paper | Chromatin remodelling | 2025-02-18 19:00 EST
Maria Theresia Watzlowik, Elisabeth Silberhorn, Sujaan Das, Ritwik Singhal, Kannan Venugopal, Simon Holzinger, Barbara Stokes, Ella Schadt, Lauriane Sollelis, Victoria A. Bonnell, Matthew Gow, Andreas Klingl, Matthias Marti, Manuel Llinás, Markus Meissner, Gernot Längst
The complex life cycle of the malaria parasite Plasmodium falciparum involves several major differentiation stages, each requiring strict control of gene expression. Fundamental changes in chromatin structure and epigenetic modifications during life cycle progression suggest a central role for these mechanisms in regulating the transcriptional program of malaria parasite development1,2,3,4,5,6. P. falciparum chromatin is distinct from other eukaryotes, with an extraordinarily high AT content (>80%)7 and highly divergent histones resulting in atypical DNA packaging properties8. Moreover, the chromatin remodellers that are critical for shaping chromatin structure are not conserved and are unexplored in P. falciparum. Here we identify P. falciparum Snf2L (PfSnf2L, encoded by PF3D7_1104200) as an ISWI-related ATPase that actively repositions P. falciparum nucleosomes in vitro. Our results demonstrate that PfSnf2L is essential, regulating both asexual development and sexual differentiation. PfSnf2L globally controls just-in-time transcription by spatiotemporally determining nucleosome positioning at the promoters of stage-specific genes. The unique sequence and functional properties of PfSnf2L led to the identification of an inhibitor that specifically kills P. falciparum and phenocopies the loss of correct gene expression timing. The inhibitor represents a new class of antimalarial transmission-blocking drugs, inhibiting gametocyte formation.
Chromatin remodelling, Parasite biology, Target identification, Target validation, Transcriptomics
Continuous-variable multipartite entanglement in an integrated microcomb
Original Paper | Quantum information | 2025-02-18 19:00 EST
Xinyu Jia, Chonghao Zhai, Xuezhi Zhu, Chang You, Yunyun Cao, Xuguang Zhang, Yun Zheng, Zhaorong Fu, Jun Mao, Tianxiang Dai, Lin Chang, Xiaolong Su, Qihuang Gong, Jianwei Wang
The generation of large-scale entangled states is crucial for quantum technologies, such as quantum computation1, communication2 and metrology3. Integrated quantum photonics that enables on-chip encoding, processing and detection of quantum light states offers a promising platform for the generation and manipulation of large-scale entangled states4,5. Generating entanglement between qubits encoded in discrete variables within single photons is challenging, owing to the difficulty of making single photons interact on photonic chips6,7,8,9,10,11. Devices that operate with continuous variables are more promising, as they enable the deterministic generation and entanglement of qumodes, in which information is encoded in light quadratures. Demonstrations so far have been limited to entanglement between two qumodes12,13,14,15,16,17,18,19,20. Here we report the deterministic generation of a continuous-variable eight-mode entanglement on an integrated optical chip. The chip delivers a quantum microcomb that produces multimode squeezed-vacuum optical frequency combs below the threshold. We verify the inseparability of our eight-mode state and demonstrate supermode multipartite entanglement over hundreds of megahertz sideband frequencies through violation of the van Loock-Furusawa criteria. By measuring the full matrices of nullifier correlations with sufficiently low off-diagonal noises, we characterize multipartite entanglement structures, which are approximate to the expected cluster-type structures for finite squeezing. This work shows the potential of continuous-variable integrated photonic quantum devices for facilitating quantum computing, networking and sensing.
Quantum information, Quantum optics
Community estimate of global glacier mass changes from 2000 to 2023
Original Paper | Climate-change impacts | 2025-02-18 19:00 EST
Michael Zemp, Livia Jakob, Inés Dussaillant, Samuel U. Nussbaumer, Noel Gourmelen, Sophie Dubber, Geruo A, Sahra Abdullahi, Liss Marie Andreassen, Etienne Berthier, Atanu Bhattacharya, Alejandro Blazquez, Laura F. Boehm Vock, Tobias Bolch, Jason Box, Matthias H. Braun, Fanny Brun, Eric Cicero, William Colgan, Nicolas Eckert, Daniel Farinotti, Caitlyn Florentine, Dana Floricioiu, Alex Gardner, Christopher Harig, Javed Hassan, Romain Hugonnet, Matthias Huss, Tómas Jóhannesson, Chia-Chun Angela Liang, Chang-Qing Ke, Shfaqat Abbas Khan, Owen King, Marin Kneib, Lukas Krieger, Fabien Maussion, Enrico Mattea, Robert McNabb, Brian Menounos, Evan Miles, Geir Moholdt, Johan Nilsson, Finnur Pálsson, Julia Pfeffer, Livia Piermattei, Stephen Plummer, Andreas Richter, Ingo Sasgen, Lilian Schuster, Thorsten Seehaus, Xiaoyi Shen, Christian Sommer, Tyler Sutterley, Désirée Treichler, Isabella Velicogna, Bert Wouters, Harry Zekollari, Whyjay Zheng
Glaciers are indicators of ongoing anthropogenic climate change1. Their melting leads to increased local geohazards2, and impacts marine3 and terrestrial4,5 ecosystems, regional freshwater resources6, and both global water and energy cycles7,8. Together with the Greenland and Antarctic ice sheets, glaciers are essential drivers of present9,10 and future11,12,13 sea-level rise. Previous assessments of global glacier mass changes have been hampered by spatial and temporal limitations and the heterogeneity of existing data series14,15,16. Here we show in an intercomparison exercise that glaciers worldwide lost 273 ± 16 gigatonnes in mass annually from 2000 to 2023, with an increase of 36 ± 10% from the first (2000-2011) to the second (2012-2023) half of the period. Since 2000, glaciers have lost between 2% and 39% of their ice regionally and about 5% globally. Glacier mass loss is about 18% larger than the loss from the Greenland Ice Sheet and more than twice that from the Antarctic Ice Sheet17. Our results arise from a scientific community effort to collect, homogenize, combine and analyse glacier mass changes from in situ and remote-sensing observations. Although our estimates are in agreement with findings from previous assessments14,15,16 at a global scale, we found some large regional deviations owing to systematic differences among observation methods. Our results provide a refined baseline for better understanding observational differences and for calibrating model ensembles12,16,18, which will help to narrow projection uncertainty for the twenty-first century11,12,18.
Climate-change impacts, Cryospheric science, Hydrology
Artificial intelligence for modelling infectious disease epidemics
Review Paper | Applied mathematics | 2025-02-18 19:00 EST
Moritz U. G. Kraemer, Joseph L.-H. Tsui, Serina Y. Chang, Spyros Lytras, Mark P. Khurana, Samantha Vanderslott, Sumali Bajaj, Neil Scheidwasser, Jacob Liam Curran-Sebastian, Elizaveta Semenova, Mengyan Zhang, H. Juliette T. Unwin, Oliver J. Watson, Cathal Mills, Abhishek Dasgupta, Luca Ferretti, Samuel V. Scarpino, Etien Koua, Oliver Morgan, Houriiyah Tegally, Ulrich Paquet, Loukas Moutsianas, Christophe Fraser, Neil M. Ferguson, Eric J. Topol, David A. Duchêne, Tanja Stadler, Patricia Kingori, Michael J. Parker, Francesca Dominici, Nigel Shadbolt, Marc A. Suchard, Oliver Ratmann, Seth Flaxman, Edward C. Holmes, Manuel Gomez-Rodriguez, Bernhard Schölkopf, Christl A. Donnelly, Oliver G. Pybus, Simon Cauchemez, Samir Bhatt
Infectious disease threats to individual and public health are numerous, varied and frequently unexpected. Artificial intelligence (AI) and related technologies, which are already supporting human decision making in economics, medicine and social science, have the potential to transform the scope and power of infectious disease epidemiology. Here we consider the application to infectious disease modelling of AI systems that combine machine learning, computational statistics, information retrieval and data science. We first outline how recent advances in AI can accelerate breakthroughs in answering key epidemiological questions and we discuss specific AI methods that can be applied to routinely collected infectious disease surveillance data. Second, we elaborate on the social context of AI for infectious disease epidemiology, including issues such as explainability, safety, accountability and ethics. Finally, we summarize some limitations of AI applications in this field and provide recommendations for how infectious disease epidemiology can harness most effectively current and future developments in AI.
Applied mathematics, Computational science, Viral infection
Nature Materials
Magnetically confined surface and bulk excitons in a layered antiferromagnet
Original Paper | Magnetic properties and materials | 2025-02-18 19:00 EST
Yinming Shao, Florian Dirnberger, Siyuan Qiu, Swagata Acharya, Sophia Terres, Evan J. Telford, Dimitar Pashov, Brian S. Y. Kim, Francesco L. Ruta, Daniel G. Chica, Avalon H. Dismukes, Michael E. Ziebel, Yiping Wang, Jeongheon Choe, Youn Jue Bae, Andrew J. Millis, Mikhail I. Katsnelson, Kseniia Mosina, Zdenek Sofer, Rupert Huber, Xiaoyang Zhu, Xavier Roy, Mark van Schilfgaarde, Alexey Chernikov, D. N. Basov
The discovery of two-dimensional van der Waals magnets has greatly expanded our ability to create and control nanoscale quantum phases. A unique capability emerges when a two-dimensional magnet is also a semiconductor that features tightly bound excitons with large oscillator strengths that fundamentally determine the optical response and are tunable with magnetic fields. Here we report a previously unidentified type of optical excitation--a magnetic surface exciton--enabled by the antiferromagnetic spin correlations that confine excitons to the surface of CrSBr. Magnetic surface excitons exhibit stronger Coulomb attraction, leading to a higher binding energy than excitons confined in bulk layers, and profoundly alter the optical response of few-layer crystals. Distinct magnetic confinement of surface and bulk excitons is established by layer- and temperature-dependent exciton reflection spectroscopy and corroborated by ab initio many-body perturbation theory calculations. By quenching interlayer excitonic interactions, the antiferromagnetic order of CrSBr strictly confines the bound electron-hole pairs within the same layer, regardless of the total number of layers. Our work unveils unique confined excitons in a layered antiferromagnet, highlighting magnetic interactions as a vital approach for nanoscale quantum confinement, from few layers to the bulk limit.
Magnetic properties and materials, Optical physics, Two-dimensional materials
Controlling Coulomb correlations and fine structure of quasi-one-dimensional excitons by magnetic order
Original Paper | Magnetic properties and materials | 2025-02-18 19:00 EST
M. Liebich, M. Florian, N. Nilforoushan, F. Mooshammer, A. D. Koulouklidis, L. Wittmann, K. Mosina, Z. Sofer, F. Dirnberger, M. Kira, R. Huber
Many surprising properties of quantum materials result from Coulomb correlations defining electronic quasiparticles and their interaction chains. In van der Waals layered crystals, enhanced correlations have been tailored in reduced dimensions, enabling excitons with giant binding energies and emergent phases including ferroelectric, ferromagnetic and multiferroic orders. Yet, correlation design has primarily relied on structural engineering. Here we present quantitative experiment-theory proof that excitonic correlations can be switched through magnetic order. By probing internal Rydberg-like transitions of excitons in the magnetic semiconductor CrSBr, we reveal their binding energy and a dramatic anisotropy of their quasi-one-dimensional orbitals manifesting in strong fine-structure splitting. We switch the internal structure from strongly bound, monolayer-localized states to weakly bound, interlayer-delocalized states by pushing the system from antiferromagnetic to paramagnetic phases. Our analysis connects this transition to the exciton's spin-controlled effective quantum confinement, supported by the exciton's dynamics. In future applications, excitons or even condensates may be interfaced with spintronics; extrinsically switchable Coulomb correlations could shape phase transitions on demand.
Magnetic properties and materials, Two-dimensional materials, Ultrafast photonics
Nature Physics
Topology shapes dynamics of higher-order networks
Review Paper | Applied mathematics | 2025-02-18 19:00 EST
Ana P. Millán, Hanlin Sun, Lorenzo Giambagli, Riccardo Muolo, Timoteo Carletti, Joaquín J. Torres, Filippo Radicchi, Jürgen Kurths, Ginestra Bianconi
Higher-order networks capture the many-body interactions present in complex systems, shedding light on the interplay between topology and dynamics. The theory of higher-order topological dynamics, which combines higher-order interactions with discrete topology and nonlinear dynamics, has the potential to enhance our understanding of complex systems, such as the brain and the climate, and to advance the development of next-generation AI algorithms. This theoretical framework, which goes beyond traditional node-centric descriptions, encodes the dynamics of a network through topological signals--variables assigned not only to nodes but also to edges, triangles and other higher-order cells. Recent findings show that topological signals lead to the emergence of distinct types of dynamical state and collective phenomena, including topological and Dirac synchronization, pattern formation and triadic percolation. These results offer insights into how topology shapes dynamics, how dynamics learns topology and how topology evolves dynamically. This Perspective primarily aims to guide physicists, mathematicians, computer scientists and network scientists through the emerging field of higher-order topological dynamics, while also outlining future research challenges.
Applied mathematics, Complex networks, Phase transitions and critical phenomena, Statistical physics, thermodynamics and nonlinear dynamics
Universal dissipative dynamics in strongly correlated quantum gases
Original Paper | Quantum simulation | 2025-02-18 19:00 EST
Yajuan Zhao, Ye Tian, Jilai Ye, Yue Wu, Zihan Zhao, Zhihao Chi, Tian Tian, Hepeng Yao, Jiazhong Hu, Yu Chen, Wenlan Chen
Dissipation is an unavoidable feature of quantum systems, typically associated with decoherence and the modification of quantum correlations. In the study of strongly correlated quantum matter, we often have to overcome or suppress dissipation to uncover the underlying quantum phenomena. However, here we demonstrate that dissipation can serve as a probe for intrinsic correlations in quantum many-body systems. Applying tunable dissipation in ultracold atomic systems, we observe universal dissipative dynamics in strongly correlated one-dimensional quantum gases. Specifically, we find a universal stretched-exponential decay of the total particle number, where the stretched exponent measures the anomalous dimension of the spectral function--a parameter for characterizing strong quantum fluctuations. This approach offers a versatile framework for probing features of strongly correlated systems, including spin-charge separation and Fermi arcs in quantum materials.
Quantum simulation, Ultracold gases
Nature Reviews Materials
Resilience pathways for halide perovskite photovoltaics under temperature cycling
Review Paper | Electronic devices | 2025-02-18 19:00 EST
Luyan Wu, Shuaifeng Hu, Feng Yang, Guixiang Li, Junke Wang, Weiwei Zuo, José J. Jerónimo-Rendon, Silver-Hamill Turren-Cruz, Michele Saba, Michael Saliba, Mohammad Khaja Nazeeruddin, Jorge Pascual, Meng Li, Antonio Abate
Metal-halide perovskite solar cells have achieved power conversion efficiencies comparable to those of silicon photovoltaic (PV) devices, approaching 27% for single-junction devices. The durability of the devices, however, lags far behind their performance. Their practical implementation implies the subjection of the material and devices to temperature cycles of varying intensity, driven by diurnal cycles or geographical characteristics. Thus, it is vital to develop devices that are resilient to temperature cycling. This Perspective analyses the behaviour of perovskite devices under temperature cycling. We discuss the crystallographic structural evolution of the perovskite layer, reactions and/or interactions among stacked layers, PV properties and photocatalysed thermal reactions. We highlight effective strategies for improving stability under temperature cycling, such as enhancing material crystallinity or relieving interlayer thermal stress using buffer layers. Additionally, we outline existing standards and protocols for temperature cycling testing and we propose a unified approach that could facilitate valuable cross-study comparisons among scientific and industrial research laboratories. Finally, we share our outlook on strategies to develop perovskite PV devices with exceptional real-world operating stability.
Electronic devices, Solar cells
Physical Review Letters
Long-Range Interacting Systems Are Locally Noninteracting
Research article | Nonequilibrium statistical mechanics | 2025-02-19 05:00 EST
Robert Mattes, Igor Lesanovsky, and Federico Carollo
Enhanced experimental capabilities to control nonlocal and power-law decaying interactions are currently fueling intense research in the domain of quantum many-body physics. Compared to their counterparts with short-ranged interactions, long-range interacting systems display novel physics, such as nonlinear light cones for the propagation of information or inequivalent thermodynamic ensembles. In this work, we consider generic long-range open quantum systems in arbitrary dimensions and focus on the so-called strong long-range regime. We prove that in the thermodynamic limit local properties, captured by reduced quantum states, are described by an emergent noninteracting theory. Here, the dynamics factorizes and the individual constituents of the system evolve independently such that no correlations are generated over time. In this sense, long-range interacting systems are locally noninteracting. This has significant implications for their relaxation behavior, for instance, in relation to the emergence of long-lived quasistationary states or to the absence of thermalization.
Phys. Rev. Lett. 134, 070402 (2025)
Nonequilibrium statistical mechanics, Open quantum systems, Nonequilibrium lattice models, Quantum spin models, Exact solutions for many-body systems, Lindblad equation, Mean field theory
Synthetic Multidimensional Aharonov-Bohm Cages in Fock State Lattices
Research article | Quantum simulation | 2025-02-19 05:00 EST
Jiajian Zhang, Wenhui Huang, Ji Chu, Jiawei Qiu, Xuandong Sun, Ziyu Tao, Jiawei Zhang, Libo Zhang, Yuxuan Zhou, Yuanzhen Chen, Yang Liu, Song Liu, Youpeng Zhong, Jian-Jian Miao, Jingjing Niu, and Dapeng Yu
Fock-state lattices, composed of photon number states with infinite Hilbert space, have emerged as a promising platform for simulating high-dimensional physics due to their potential to extend into arbitrarily high dimensions. Here, we demonstrate the construction of multidimensional Fock-state lattices using superconducting quantum circuits. By controlling artificial gauge fields within their internal structures, we investigate flux-induced extreme localization dynamics, such as Aharonov-Bohm caging, extending from 2D to 3D. We also explore the coherent interference of quantum superposition states, achieving extreme localization within specific subspaces assisted by quantum entanglement. Our findings pave the way for manipulating the behavior of a broad class of quantum states in higher-dimensional systems.
Phys. Rev. Lett. 134, 070601 (2025)
Quantum simulation, Superconducting qubits
Time-Efficient Logical Operations on Quantum Low-Density Parity Check Codes
Research article | Quantum algorithms & computation | 2025-02-19 05:00 EST
Guo Zhang and Ying Li
We propose schemes capable of measuring an arbitrary set of commutative logical Pauli operators in time independent of the number of operators. The only condition is commutativity, a fundamental requirement for simultaneous measurements in quantum mechanics. Quantum low-density parity check (qLDPC) codes show great promise for realizing fault-tolerant quantum computing. They are particularly significant for early fault-tolerant technologies as they can encode many logical qubits using relatively few physical qubits. By achieving simultaneous measurements of logical operators, our approaches enable fully parallelized quantum computing, thus minimizing computation time. Our schemes are applicable to any qLDPC codes and maintain the low density of parity checks while measuring multiple logical operators simultaneously. These results enhance the feasibility of applying early fault-tolerant technologies to practical problems.
Phys. Rev. Lett. 134, 070602 (2025)
Quantum algorithms & computation, Quantum error correction
Realization of a Crosstalk-Free Two-Ion Node for Long-Distance Quantum Networking
Research article | Quantum communication | 2025-02-19 05:00 EST
P.-C. Lai, Y. Wang, J.-X. Shi, Z.-B. Cui, Z.-Q. Wang, S. Zhang, P.-Y. Liu, Z.-C. Tian, Y.-D. Sun, X.-Y. Chang, B.-X. Qi, Y.-Y. Huang, Z.-C. Zhou, Y.-K. Wu, Y. Xu, Y.-F. Pu, and L.-M. Duan
Trapped atomic ions constitute one of the leading physical platforms for building the quantum repeater nodes to realize large-scale quantum networks. In a long-distance trapped-ion quantum network, it is essential to have crosstalk-free dual-type qubits: one type, called the communication qubit, to establish an entangling interface with telecom photons; and the other type, called the memory qubit, to store quantum information immune from photon scattering under entangling attempts. Here, we report the first experimental implementation of a telecom-compatible and crosstalk-free quantum network node based on two trapped \(^{40}{\mathrm{Ca}}^{+}\) ions. The memory qubit is encoded on a long-lived metastable level to avoid crosstalk with the communication qubit encoded in another subspace of the same ion species, and a quantum wavelength conversion module is employed to generate heralded ion-photon entanglement over a 12 km fiber. Our work therefore constitutes an important step toward the realization of quantum repeaters and long-distance quantum networks.
Phys. Rev. Lett. 134, 070801 (2025)
Quantum communication, Quantum communication, protocols & technology, Quantum information processing, Quantum information with trapped ions, Quantum networks, Quantum state transfer
Search for Reactor-Produced Millicharged Particles with Skipper-CCDs at the CONNIE and Atucha-II Experiments
Research article | Particle dark matter | 2025-02-19 05:00 EST
Alexis A. Aguilar-Arevalo et al. (CONNIE and Atucha-II Collaborations)
Millicharged particles, proposed by various extensions of the standard model, can be created in pairs by high-energy photons within nuclear reactors and can interact electromagnetically with electrons in matter. Recently, the existence of a plasmon peak in the interaction cross section with silicon in the eV range was highlighted as a promising approach to enhance low-energy sensitivities. The CONNIE and Atucha-II reactor neutrino experiments utilize Skipper-CCD sensors, which enable the detection of interactions in the eV range. We present world-leading limits on the charge of millicharged particles within a mass range spanning 6 orders of magnitude, derived through a comprehensive analysis and the combination of data from both experiments.
Phys. Rev. Lett. 134, 071801 (2025)
Particle dark matter, Particle interactions, Neutrino detection, Particle production, Solid-state detectors
Diffractive Imaging of Transient Electronic Coherences in Molecules with Electron Vortices
Research article | Chemical Physics & Physical Chemistry | 2025-02-19 05:00 EST
Haowei Wu and Haiwang Yong
Direct imaging of transient electronic coherences in molecules has been challenging, with the potential to control electron motions and influence reaction outcomes. We propose a novel time-resolved vortex electron diffraction technique to spatially resolve transient electronic coherences in isolated molecules. By analyzing helical dichroism diffraction signals, the contribution of electronic populations cancels out, isolating the purely electronic coherence signals. This allows direct monitoring of the time evolution and decoherence of transient electronic coherences in molecules.
Phys. Rev. Lett. 134, 073001 (2025)
Chemical Physics & Physical Chemistry, Chemical reactions, Light-matter interaction, Quantum coherence & coherence measures, Scattering of atoms, molecules, clusters & ions, Ultrafast phenomena, Electron diffraction
Attosecond Clocking and Control of Strong Field Quantum Trajectories
Research article | Multiphoton or tunneling ionization & excitation | 2025-02-19 05:00 EST
Andrew J. Piper, Qiaoyi Liu, Abraham Camacho Garibay, Dietrich Kiesewetter, Vyacheslav Leshchenko, Jens E. Bækhøj, Pierre Agostini, Kenneth J. Schafer, Louis F. DiMauro, and Yaguo Tang
We introduce a quantum trajectory selector method capable of resolving individual quantum trajectories responsible for strong-field phenomena in real time, revealing the dependence of the electron dynamics on the ionization time. Using an attosecond extreme ultraviolet pulse train, we select the moment of ionization and measure the rates of rescattered electron emission and double ionization driven by a phase locked near IR (1.77 or \(2.4\text{ }\text{ }\mathrm{\mu }\mathrm{m}\)) field. We show that there is an intensity-dependent shift in the ionization time associated with double ionization, and we clock this shift as it varies by 250 as. The quantum trajectory selector provides a new attosecond paradigm for expanding our understanding of recollision-driven physics.
Phys. Rev. Lett. 134, 073201 (2025)
Multiphoton or tunneling ionization & excitation, Strong field ionization & excitation, Ultrafast phenomena, Attosecond laser irradiation
Ultrafast Spin Rotation of Relativistic Lepton Beams via Terahertz Wave in a Dielectric-Lined Waveguide
Research article | Beam optics transport | 2025-02-19 05:00 EST
Zhong-Peng Li, Yu Wang, Ting Sun, Feng Wan, Yousef I. Salamin, Mamutjan Ababekri, Qian Zhao, Kun Xue, Ye Tian, Wen-Qing Wei, and Jian-Xing Li
Spin rotation is central for the spin manipulation of lepton beams which, in turn, plays an important role in investigation of the properties of spin-polarized lepton beams and the examination of spin-dependent interactions. However, realization of compact and ultrafast spin rotation of lepton beams, between longitudinal and transverse polarizations, still faces significant challenges. Here, we put forward a novel method for ultrafast (picosecond timescale) spin rotation of a relativistic lepton beam via employing a moderate-intensity terahertz (THz) wave in a dielectric-lined waveguide (DLW). The lepton beam undergoes spin precession induced by the THz magnetic field. We find that optimizing the lepton velocity and THz phase velocity in the DLW can mitigate the impact of transverse Lorentz forces on the lepton beam and increase the precession frequency, thereby maintaining the beam quality and enhancing the efficiency of transverse-to-longitudinal spin rotation. The final polarization degree of the lepton beam exceeds 98%, and the energy spread can be improved significantly. Flexibility in adjusting the electromagnetic modes within the DLW adds further potential for spin manipulation and holds promise for advancing the development of spin-polarized particle beams, which has broad applications in materials science and atomic, nuclear, and high-energy physics.
Phys. Rev. Lett. 134, 075001 (2025)
Beam optics transport, Beam polarization, Dielectric properties, Electron beams & optics, Geometrical & wave optics, Light propagation, transmission & absorption, Polarization of light, Spin dynamics, Ultrafast optics, Waveguides, Terahertz sources, Terahertz techniques
Switching Two-Dimensional Sliding Ferroelectrics by Mechanical Bending
Research article | Ferroelectricity | 2025-02-19 05:00 EST
Ri He, Hua Wang, Fenglin Deng, Yuxiang Gao, Bingwen Zhang, Yubai Shi, Run-Wei Li, and Zhicheng Zhong
Two-dimensional van der Waals materials, possessing a unique stacking degree of freedom, offer an alternative strategy for modulating their properties through interlayer sliding. Controlling the stacking order is crucial for tuning material properties and developing slidetronics-based devices. Here, using machine-learning potentials, we propose a mechanical bending approach to manipulate stacking orders and related properties in sliding ferroelectric h-BN, 3R-\({\mathrm{MoS}}_{2}\), and nonferroelectric bilayer graphene. Our simulations predict the formation of irreversible kinks in bent bilayers, deviating from the expected arclike deformation. This kink formation arises from the interplay between bending energy and interlayer stacking energy. Notably, the bending-induced kink contains a ferroelectric topological domain wall that reverses the polarization of sliding ferroelectrics, a mechanism distinct from the conventional flexoelectric effect. This work proposes an exciting mechanical bending approach to dynamically manipulate the stacking order and associated optical, topological, ferroelectric, and magnetic properties in van der Waals layered materials.
Phys. Rev. Lett. 134, 076101 (2025)
Ferroelectricity, Flexoelectricity, Bilayer films, Hexagonal boron nitride, Density functional theory, Machine learning
Spontaneous Localization at a Potential Saddle Point from Edge State Reconstruction in a Quantum Hall Point Contact
Research article | Fractional quantum Hall effect | 2025-02-19 05:00 EST
Liam A. Cohen, Noah L. Samuelson, Taige Wang, Kai Klocke, Cian C. Reeves, Takashi Taniguchi, Kenji Watanabe, Sagar Vijay, Michael P. Zaletel, and Andrea F. Young
Quantum point contacts (QPCs) are an essential component in mesoscopic devices. Here, we study the transmission of quantum Hall edge modes through a gate-defined QPC in monolayer graphene. We observe resonant tunneling peaks and a nonlinear conductance pattern characteristic of Coulomb-blockaded localized states. The in-plane electric polarizability reveals the states are localized at a classically unstable electrostatic saddle point. We explain this unexpected finding within a self-consistent Thomas-Fermi model, finding that localization of a zero-dimensional state at the saddle point is favored whenever the applied confinement potential is sufficiently soft compared to the Coulomb energy. Our results provide a direct demonstration of Coulomb-driven reconstruction at the boundary of a quantum Hall system.
Phys. Rev. Lett. 134, 076302 (2025)
Fractional quantum Hall effect, Mesoscopics, Quantum Hall effect, Graphene, Point contacts
Anomalies in the Electronic Stopping of Slow Antiprotons in LiF
Research article | Atomic & molecular collisions | 2025-02-19 05:00 EST
Guerda Massillon-JL, Alfredo A. Correa, Xavier Andrade, and Emilio Artacho
We present first-principles theoretical calculations for the electronic stopping power (SP) of both protons and antiprotons in LiF. Our results show the presence of the Barkas effect: a higher stopping for positively charged particles than their negatively charged antiparticles. In contrast, a previous study has predicted an anti-Barkas effect (higher stopping for negative charges) at low velocity [Qi, Bruneval and Maliyov, Phys. Rev. Lett. 128, 043401 (2022)]. We explain this discrepancy by showing that this anti-Barkas effect appears for highly symmetric trajectories and disappears when considering trajectories that better reproduce the experimental setup. Our low-velocity results show that the SP of both protons and antiproton vanish for velocities under 0.1 a.u.
Phys. Rev. Lett. 134, 076401 (2025)
Atomic & molecular collisions, Electronic excitation & ionization, First-principles calculations, 3-dimensional systems, Irradiation
General Method to Construct Flat Bands in Two-Dimensional Lattices
Research article | Crystal symmetry | 2025-02-19 05:00 EST
H. T. Li, T. Z. Ji, R. G. Yan, W. L. Fan, Z. X. Zhang, L. Sun, B. F. Miao, G. Chen, X. G. Wan, and H. F. Ding
Searching for new materials hosting flat bands is pivotal for exploring strongly correlated effects and designing sensitive quantum devices, but remains challenging. We present a general method for realizing flat bands based on mathematical optimization and symmetry analysis. The method enables the discovery of \(\sim 1000\) types of two-dimensional lattices that can host flat bands, in sharp contrast with \(\sim 10\) flat-band lattices predicted previously besides the well-known ones. We further verify the method using first-principles calculations. Our approach provides new insights for the design of flat-band lattices, particularly when aiming to create experimentally feasible configurations.
Phys. Rev. Lett. 134, 076402 (2025)
Crystal symmetry, Density of states, Electronic structure, Flat bands, Local density of states, First-principles calculations
Extracting the Luttinger Parameter from a Single Wave Function
Research article | Conformal field theory | 2025-02-19 05:00 EST
Bi-Yang Tan, Yueshui Zhang, Hua-Chen Zhang, Wei Tang, Lei Wang, Hong-Hao Tu, and Ying-Hai Wu
The low-energy physics of Tomonaga-Luttinger liquids (TLLs) is controlled by the Luttinger parameter. We demonstrate that this parameter can be extracted from a single wave function for one-component TLLs with periodic boundary condition. This method relies on the fact that TLLs are described by conformal field theory in which crosscap states can be constructed. The overlaps between the crosscap states and the ground state as well as some excited states are proved to be universal numbers that directly reveal the Luttinger parameter. In microscopic lattice models, crosscap states are formed by putting each pair of antipodal sites into a maximally entangled state. Analytical and numerical calculations are performed in a few representative models to substantiate the conformal field theory prediction. The extracted Luttinger parameters are generally quite accurate in finite-size systems with moderate lengths, so there is no need to perform data fitting and/or finite-size scaling.
Phys. Rev. Lett. 134, 076501 (2025)
Conformal field theory, 1-dimensional spin chains, Luttinger liquid model, Matrix product states
Ground State of the \(S=1\) Antiferromagnetic Heisenberg Chain Is Topologically Nontrivial if Gapped
Magnetism | 2025-02-19 05:00 EST
Hal Tasaki
Theoretical work indicates that a realistic model of a one-dimensional quantum magnet has a topologically nontrivial ground state.
Phys. Rev. Lett. 134, 076602 (2025)
Magnetism, Phase transitions, Quantum phase transitions, Symmetry protected topological states, Topological phases of matter, Spin chains
Ferroelectric Spin-Orbit Valve Effect
Research article | Quantum transport | 2025-02-19 05:00 EST
L. L. Tao, Mingbo Dou, Xianjie Wang, and E. Y. Tsymbal
In ferroelectric (FE) semiconductors with strong spin-orbit coupling, the electron's spin direction is locked to its momentum by an intrinsic spin-orbit field (SOF) switchable by ferroelectric polarization. This provides a promising platform for novel nonvolatile spintronic devices. Here, we propose exploiting the switchable SOF to realize a FE spin-orbit valve (FE-SOV), where two FE semiconductors are separated by a thin barrier layer. Because of the locking between the SOF and polarization direction, the conductance of the FE-SOV strongly depends on the relative orientation of polarization of the two FE semiconductors. Using a tight-binding model and density functional theory calculations for FE-SOVs based on two-dimensional FE SnTe and Bi, we demonstrate a giant FE-SOV effect that is characterized by the conductance change of several orders in magnitude. Our work enriches spin-orbit physics of ferroelectrics and proposes a new type of all-electric control of a nonvolatile spin-orbitronic device, which holds promise for future electronic and memory applications.
Phys. Rev. Lett. 134, 076801 (2025)
Quantum transport, Spin-orbit coupling, Spintronics, Ferroelectrics, Multiferroics, First-principles calculations, Tight-binding model
Large Tunneling Magnetoresistance in Nonvolatile 2D Hybrid Spin Filters
Research article | Spin filtering | 2025-02-19 05:00 EST
Xiaoyu Wang, Lihao Zhang, Miao He, Qi Li, Wenqin Song, Kunlin Yang, Shuxi Wang, Takashi Taniguchi, Kenji Watanabe, Lei Zhang, Wu Shi, Yingchun Cheng, Zhe Qu, Jie Pan, and Zhe Wang
Ferromagnetic semiconductors offer an efficient way to achieve high spin polarization via spin filtering effect. Large tunneling magnetoresistance (TMR) can then be realized when multiple spin filters are put in series, as recently demonstrated in van der Waals 2D A-type antiferromagnets such as \({\mathrm{CrI}}_{3}\) and CrSBr. However, the interlayer antiferromagnetic ground state of these magnets inherently results in a high resistance state at zero field, and this volatile behavior limits potential applications. Here we fabricate hybrid spin filters using 2D ferromagnetic metal \({\mathrm{Fe}}_{3}{\mathrm{GeTe}}_{2}\) and semiconductor \({\mathrm{CrBr}}_{3}\), which are nonvolatile as two magnets are magnetically decoupled. We achieve large TMR of around 100%, with its temperature dependence well fitted by the extended Julli'ere model. Additionally, the devices allow spin injection tuned through bias voltage, and TMR polarity reversals are observed. Our work opens a new route to develop 2D magnetic semiconductor based spintronics.
Phys. Rev. Lett. 134, 077001 (2025)
Spin filtering, Spin polarization, Spintronics, Tunneling magnetoresistance, 2-dimensional systems, Magnetic tunnel junctions, Resistivity measurements
Physical Review X
Phonon Thermal Hall Effect in Mott Insulators via Skew Scattering by the Scalar Spin Chirality
Research article | Phonons | 2025-02-19 05:00 EST
Taekoo Oh and Naoto Nagaosa
Spins have been long thought to be the primary contributor to the thermal Hall effect in insulators. Theoretical work shows that vibrations can contribute just as much.
Phys. Rev. X 15, 011036 (2025)
Phonons, Thermal Hall effect, Noncollinear magnets, Strongly correlated systems
arXiv
Global Ashkin-Teller Phase Diagrams in Two and Three Dimensions: Multicritical Bifurcation versus Double Tricriticality Endpoint
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-02-19 20:00 EST
Ibrahim Kecoglu, A. Nihat Berker
The global phase diagrams of the Askin-Teller model are calculated in d=2 and 3 by renormalization-group theory that is exact on the hierarchical lattice and approximate on the recently improved Migdal-Kadanoff procedure. Three different ordered phases occur in the dimensionally distinct phase diagrams that reflect three-fold order-parameter permutation symmetry, a closed symmetry line, and a quasi-disorder line. First- and second-order phase boundaries are obtained. In d=2, second-order phase transitions meeting at a bifurcation point are seen. In d=3, first- and second-order phase transitions are separated by tricritical and critical endpoints.
Statistical Mechanics (cond-mat.stat-mech)
4 pages, 3 figures, 1 table. arXiv admin note: substantial text overlap with arXiv:2309.05543
Physica A 630, 129248 (2023)
Quantum Critical Dynamics Induced by Topological Zero Modes
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-19 20:00 EST
Ilia Komissarov, Tobias Holder, Raquel Queiroz
We investigate the low-frequency ac transport in the Su-Schrieffer-Heeger (SSH) chain with chiral disorder near the topological delocalization transition. Our key finding is that the formation of hybridized pairs of topological domain wall zero modes leads to the anomalous logarithmic scaling of the ac conductivity \(\sigma(\omega) \sim \log \omega\) at criticality, and \(\sigma(\omega) \sim \omega^{2 \delta} \log ^2 \omega\) away from it. Using the combination of real-space renormalization group analysis and qualitative hybridization arguments, we demonstrate that the form of the scaling of ac conductivity at criticality stems directly from the stretched-exponential (\(\psi(x) \sim e^{-s \sqrt{x}}\)) spatial decay of zero-mode wavefunctions at the critical point.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Disordered Systems and Neural Networks (cond-mat.dis-nn)
11 pages, 4 figures
Canted magnetism and \(\mathbb{Z}_2\) fractionalization in metallic states of the Lieb lattice Hubbard model near quarter filling
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-19 20:00 EST
Alexander Nikolaenko, Pietro M. Bonetti, Anant Kale, Martin Lebrat, Markus Greiner, Subir Sachdev
A recent experiment has examined ultracold, fermionic, spin-1/2 \(^6\)Li atoms in the Lieb lattice at different Hubbard repulsion \(U\) and filling fractions \(\nu\) (Lebrat et al. arXiv:2404.17555). At \(\nu=1/2\) and small \(U\), they observe an enhanced compressibility on the \(p_{x,y}\) sites, pointing to a flat band near the Fermi energy. At \(\nu=1/2\) and large \(U\) they observe an insulating ferrimagnet. Both small and large \(U\) observations at \(\nu=1/2\) are consistent with theoretical expectations. Surprisingly, near \(\nu=1/4\) and large \(U\), they again observe a large \(p_{x,y}\) compressibility, pointing to a flat \(p_{x,y}\) band of fermions across the Fermi energy. Our Hartree-Fock computations near \(\nu=1/4\) find states with canted magnetism (and related spiral states) at large \(U\), which possess nearly flat \(p_{x,y}\) bands near the Fermi level. We employ parton theories to describe quantum fluctuations of the magnetic order found in Hartree-Fock. We find a metallic state with \(\mathbb{Z}_2\) fractionalization possessing gapless, fermionic, spinless `chargons' carrying \(\mathbb{Z}_2\) gauge charges which have a nearly flat \(p_{x,y}\) band near their Fermi level: this fractionalized metal is also consistent with observations. Our DMRG study does not indicate the presence of magnetic order, and so supports a fractionalized ground state. Given the conventional ferrimagnetic insulator at \(\nu=1/2\), the \(\mathbb{Z}_2\) fractionalized metal at \(\nu=1/4\) represents a remarkable realization of doping-induced fractionalization.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Gases (cond-mat.quant-gas)
Non-Abelian phases from the condensation of Abelian anyons
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-19 20:00 EST
Misha Yutushui, Maria Hermanns, David F. Mross
The observed fractional quantum Hall (FQH) plateaus follow a recurring hierarchical structure that allows an understanding of complex states based on simpler ones. Condensing the elementary quasiparticles of an Abelian FQH state results in a new Abelian phase at a different filling factor, and this process can be iterated . We show that condensing clusters of the same quasiparticles into an Abelian state can instead realize non-Abelian FQH states. In particular, condensing quasiparticle pairs in the \(\nu=\frac{2}{3}\) Laughlin state yields the anti-Pfaffian phase at half-filling. We moreover show that the successive condensation of Laughlin quasiparticles produces quantum Hall states whose fillings coincide with the most prominent plateaus in the first excited Landau level of GaAs. More generally, such condensation can realize any non-Abelian FQH state that admits a parton representation. This surprising result is supported by an exact analysis of explicit wavefunctions, field theory arguments, conformal-field theory constructions of trial states, and numerical simulations.
Strongly Correlated Electrons (cond-mat.str-el)
4+7 pages, 2+4 figures, 1+3 tables
Quantum geometric photocurrents of quasiparticles in superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-19 20:00 EST
Daniel Kaplan, Kevin P. Lucht, Pavel A. Volkov, J.H. Pixley
Nonlinear optical response is a sensitive probe of the geometry and symmetry of electronic Bloch states in solids. Here, we extend this notion to the Bogoliubiov-de-Gennes (BdG) quasiparticles in superconductors. We present a theory of photocurrents in superconductors and show that they sensitively depend on the quantum geometry of the BdG excitation spectrum. For all light polarizations, the photocurrent is proportional to the quantum geometric tensor: for linear polarized light it is related to the quantum metric and for circular polarization -- the Berry curvature dipole of the associated BdG bands. We further relate the photocurrent to the ground state symmetries, providing a symmetry dictionary for the allowed photocurrent responses. For light not at normal incidence to the sample, photocurrent probes time-reversal symmetry breaking in systems with chiral point groups (such as twisted bilayers). We demonstrate that photocurrents allow to probe topology and TRS breaking in twisted \(d\)-wave superconductors and test the nature of superconductivity in twisted WSe\(_2\) and multilayer stacks of rhombohedral graphene. Our results pave the way to contactless measurement of the quantum geometric properties and symmetry of superconductivity in materials and heterostructures.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
6 pages + supplement
Transformations induced by hydrostatic pressure on lead metasilicate phases
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-19 20:00 EST
Ariano D. Rodrigues, Thiago R. Cunha, Rafaella B. Pena, Ulisses F. Kaneko, Lucas M. E. Pinho, Benjamim J. A. Moulton, Paulo S. Pizani
For most silicates, controlling the crystallization - through the nucleation, growth, and stabilization of distinct crystalline phase - is critical to achieving the desired physical properties in the final glass-ceramic product. In this context, lead metasilicate PbSiO3 (PS) represents an ideal model system for investigating structural evolution under varying pressure and temperature conditions. This is primarily due to its distinct Raman signatures and the capability of resolving its structure with high precision through diffraction measurements. These attributes enable a comprehensive evaluation of the thermodynamic quantities involved in this complex process, which are essential for the physical description of the crystallization of glasses undergoing heterogeneous nucleation. We report on high-pressure in situ analyses of three crystalline phases of PS: a stable monoclinic structure, a metastable hexagonal structure, and a lower symmetry metastable phase. Combined high-pressure Raman and synchrotron X-ray diffraction indicate that the structures are highly sensitive to the application of hydrostatic pressure and that significant structural rearrangements can be achieved in moderate pressure regimes. Such analyses also enabled determining important thermodynamic variables of those systems, such as compressibility. From an applied perspective, our findings demonstrate that the application of pressure achievable using large-volume presses and capable of altering the energy states of such phases, can be regarded as a promising strategy to influence the stages of the overall crystallization process. This approach opens new avenues for the development of novel structures and properties in the resulting glass-ceramic materials
Materials Science (cond-mat.mtrl-sci)
24 pages, 7 figures
Vibrational properties of photochromic yttrium oxyhydride and oxydeuteride thin films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-19 20:00 EST
Martins Zubkins, Jevgenijs Gabrusenoks, Rihards Aleksis, George Chikvaidze, Edvards Strods, Viktors Vibornijs, Alons Lends, Karlis Kundzins, Juris Purans
A comprehensive study of the vibrational properties of photochromic yttrium oxyhydride (YHO) and oxydeuteride (YDO) thin films is presented. These films are deposited using reactive magnetron sputtering, followed by post-oxidation. Our investigation employs vibrational Fourier-transform infrared (FTIR) spectroscopy, in conjunction with first-principles Density Functional Theory (DFT) calculations. The FTIR spectra of the films reveal broad vibrational bands, primarily attributed to the disordered structure containing small crystallites (<10 nm), as confirmed by solid-state nuclear magnetic resonance and X-ray diffraction measurements. An isotopic shift from approximately 900 to 745 cm-1 is observed in the hydrogen/deuterium-related vibration band, while the lower frequency bands (< 600 cm-1) remain unaffected upon replacement of hydrogen with deuterium. These experimental observations are consistent with the DFT theoretical calculations for various stable YHO lattices reported in the literature. Illumination of the films with ultraviolet light at 3.3 eV leads to additional absorption not only in the visible light range but also up to approximately 2000 cm-1 in the mid-infrared region. However, no phase transformation change or formation of hydroxyl (OH) groups are observed following illumination. Our findings provide valuable insight into the vibrational and photochromic properties of YH(D)O thin films.
Materials Science (cond-mat.mtrl-sci)
25 pages, 5 figures
Journal of Alloys and Compounds 1015 (2025) 178917
Implicit Geometric Descriptor-Enabled ANN Framework for a Unified Structure-Property Relationship in Architected Nanofibrous Materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-19 20:00 EST
Bhanugoban Maheswaran, Komal Chawla, Abhishek Gupta, Ramathasan Thevamaran
Hierarchically architected nanofibrous materials, such as the vertically aligned carbon nanotube (VACNT) foams, draw their exceptional mechanical properties from the interplay of nanoscale size effects and inter-nanotube interactions within and across architectures. However, the distinct effects of these mechanisms, amplified by the architecture, on different mechanical properties remain elusive, limiting their independent tunability for targeted property combinations. Reliance on architecture-specific explicit design parameters further inhibits the development of a unified structure-property relationship rooted in those nanoscale mechanisms. Here, we introduce two implicit geometric descriptors -- multi-component shape invariants (MCSI) -- in an artificial neural network (ANN) framework to establish a unified structure-property relationship that governs diverse architectures. The MCSIs effectively capture the key nanoscale mechanisms that give rise to the bulk mechanical properties such as specific-energy absorption, peak stress, and average modulus. Exploiting their ability to predict mechanical properties for designs that are even outside of the training data, we propose generalized design strategies to achieve desired mechanical property combinations in architected VACNT foams. Such implicit descriptor-enabled ANN frameworks can guide the accelerated and tractable design of complex hierarchical materials for applications ranging from shock-absorbing layers in extreme environments to functional components in soft robotics.
Materials Science (cond-mat.mtrl-sci)
Nature of the ferromagnet-paramagnet transition in Y\(_{1-x}\)Ca\(_{x}\)TiO\(_{3}\)
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-19 20:00 EST
S. Hameed, I. Khayr, J. Joe, G. Q. Zhao, Y. Cai, K. M. Kojima, S. Chi, T. J. Williams, M. Matsuda, Y. J. Uemura, M. Greven
Neutron scattering, magnetometry, and muon spin rotation (\(\mu\)SR) measurements were performed to investigate the magnetic order and spin dynamics across the ferromagnet-to-paramagnet transition in the hole-doped Mott insulator Y\(_{1-x}\)Ca\(_x\)TiO\(_3\). We find that the transition proceeds through a volume-wise phase separation into ferromagnetic and paramagnetic regions. Spin fluctuations with a characteristic timescale of \(\sim\) 0.1 \(\mu\)s, as detected via \(\mu\)SR, are observed to appear at Ca concentrations \(x \geq 0.10\). The magnetic phase separation, accompanied by a modest dynamic response, represents a novel behavior in Mott systems near the loss of magnetic order. It is linked to a previously observed insulator-metal transition and the associated electronic phase separation into hole-poor Mott insulating and hole-rich metallic phases for \(0 < x < 0.50\). In particular, the \(x\)-dependence of the paramagnetic volume fraction strongly correlates with that of the volume fraction of the hole-rich metallic phase. The spin-wave spectra reveal a doping-induced crossover from isotropic to two-dimensional anisotropic exchange interactions, reflecting substantial changes in the orbital state with increasing Ca content.
Strongly Correlated Electrons (cond-mat.str-el)
6 figures; supplement included
Robust Super-Moiré in Large Angle Single-Twist Bilayers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-19 20:00 EST
Yanxing Li, Chuqiao Shi, Fan Zhang, Xiaohui Liu, Yuan Xue, Viet-Anh Ha, Qiang Gao, Chengye Dong, Yu-chuan Lin, Luke N Holtsman, Nicolas Morales-Durán, Hyunsue Kim, Yi Jiang, Madisen Holbrook, James Hone, Katayun Barmak, Joshua Robinson, Xiaoqin Li, Feliciano Giustino, Eslam Khalaf, Yimo Han, Chih-Kang Shih
Forming long wavelength moiré superlattices (MSL) at small-angle twist van der Waals (vdW) bilayers has been a key approach to creating moiré flat bands. The small-angle twist, however, leads to strong lattice reconstruction, causing domain walls and moiré disorders, which pose considerable challenges in engineering such platforms. At large twist angles, the rigid lattices render a more robust, but shorter wavelength MSL, making it difficult to engineer flat bands. Here, we depict a novel approach to tailoring robust super-moiré (SM) structures that combines the advantages of both small-twist and large-twist transition metal dichalcogenides (TMDs) bilayers using only a single twist angle near a commensurate angle. Structurally, we unveil the spontaneous formation of a periodic arrangement of three inequivalent commensurate moiré (CM) stacking, where the angle deviation from the commensurate angle can tune the periodicity. Electronically, we reveal a large set of van Hove singularities (VHSs) that indicate strong band hybridization, leading to flat bands near the valence band maximum. Our study paves the way for a new platform of robust SM bilayers with structural rigidity and controllable wavelength, extending the investigation of the interplay among band topology, quantum geometry, and moiré superconductivity to the large twist angle regime.
Materials Science (cond-mat.mtrl-sci)
Strong coupling of polaritons at room temperature in a GaAs/AlGaAs structure
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-19 20:00 EST
Hassan Alnatah, Shuang Liang, Qiaochu Wan, Jonathan Beaumariage, Ken West, Kirk Baldwin, Loren N. Pfeiffer, Man Chun Alan Tam, Zbigniew R. Wasilewski, David W. Snoke
We report direct measurement of the dispersion relation of polaritons in GaAs/AlGaAs microcavity structures at room temperature, which clearly shows that the polaritons are in the strong coupling limit. The Rabi splitting of the polariton states decreases as the polariton gas increases in density, but even when the polariton gas becomes a coherent, Bose-condensate-like state, the polaritons retain a strong exciton component, as seen in the nonlinear energy shift of the light emission. This opens up the possibility of polaritonic devices at room temperature in a material system which can be grown with very high quality and uniformity.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Gases (cond-mat.quant-gas)
Orbitronics in Two-dimensional Materials
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-19 20:00 EST
Tarik P. Cysne, Luis M. Canonico, Marcio Costa, R. B. Muniz, Tatiana G. Rappoport
Orbitronics explores the control and manipulation of electronic orbital angular momentum in solid-state systems, opening new pathways for information processing and storage. One significant advantage of orbitronics over spintronics is that it does not rely on spin-orbit coupling, thereby broadening the range of non-magnetic materials that can be utilized for these applications. It also introduces new topological features related to electronic orbital angular momentum, and clarifies some long-standing challenges in understanding experiments that rely on the conventional concept of valley transport. This review highlights recent advances in orbitronics, particularly in relation to two-dimensional materials. We examine the fundamental principles underlying the generation, transport, and dynamics of orbital angular momentum to illustrate how the unique properties of two-dimensional materials can promote orbitronic phenomena. We also outline potential future research directions and address some outstanding questions in this field.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
16 pages, 3 figures
Edge non-collinear magnetism in nanoribbons of Fe3GeTe2 and Fe3GaTe2
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-19 20:00 EST
R. Cardias, Anders Bergman, Hugo U. R. Strand, R. B. Muniz, Marcio Costa
Fe3GeTe2 and Fe3GaTe2 are ferromagnetic conducting materials of van der Waals-type with unique magnetic properties that are highly promising for the development of new spintronic, orbitronic and magnonic devices. Even in the form of two-dimensional-like ultrathin films, they exhibit relatively high Curie temperature, magnetic anisotropy perpendicular to the atomic planes and multiple types of Hall effects. We explore nanoribbons made from single layers of these materials and show that they display non-collinear magnetic ordering at their edges. This magnetic inhomogeneity allows angular momentum currents to generate magnetic torques at the sample edges, regardless of their polarization direction, significantly enhancing the effectiveness of magnetization manipulation in these systems. We also demonstrate that it is possible to rapidly reverse the magnetization direction of these nanostructures by means of spin-orbit and spin-transfer torques with rather low current densities, making them quite propitious for non-volatile magnetic memory units.
Materials Science (cond-mat.mtrl-sci)
5 pages, 4 figures
Bell correlations between momentum-entangled pairs of \(^4\text{He}^*\) atoms
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-02-19 20:00 EST
Y. S. Athreya, S. Kannan, X. T. Yan, R. J. Lewis-Swan, K. V. Kheruntsyan, A. G. Truscott, S. S. Hodgman
Nonlocal entanglement between pair-correlated particles is a highly counter-intuitive aspect of quantum mechanics, where measurement on one particle can instantly affect the other, regardless of distance. While the rigorous Bell's inequality framework has enabled the demonstration of such entanglement in photons and atomic internal states, no experiment has yet involved motional states of massive particles. Here we report the experimental observation of Bell correlations in motional states of momentum-entangled ultracold helium atoms. Momentum-entangled pairs are generated via \(s\)-wave collisions. Using a Rarity-Tapster interferometer and a Bell-test framework, we observe atom-atom correlations required for violation of a Bell inequality. This result shows the potential of ultracold atoms for fundamental tests of quantum mechanics and opens new avenues to studying gravitational effects in quantum states.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
Geometric dependence of critical current magnitude and nonreciprocity in planar Josephson junctions
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-19 20:00 EST
William F. Schiela, Melissa Mikalsen, William M. Strickland, Javad Shabani
Planar Josephson junctions in a magnetic field exhibit the superconducting diode effect, by which the critical current magnitude depends on the polarity of the transport current. A number of different mechanisms for the effect have been this http URL, we study symmetric, T-shaped planar Josephson junctions with semiconducting weak links in an in-plane magnetic field perpendicular to an applied current bias. In particular, we vary the longitudinal width (i.e. parallel to the current) of the superconducting contacts and the voltage of an electrostatic gate. We observe an increase in both critical current and diode efficiency with increasing contact width and relate the critical current behavior to the induced coherence length of the Andreev bound states that mediate the supercurrent flow through the junction. We further observe a linear trend, with respect to inverse contact width, of the field at which the diode efficiency is maximized, which saturates as the contact width becomes large compared to the coherence length. The smaller field at which the critical current is maximized additionally exhibits a strong gate dependence. We interpret these observations in the context of multiple underlying mechanisms, including spin--orbit coupling and orbital effects.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Analytical Diagonalization of Fermi Gas-like Hamiltonians using the Sommerfeld-Watson Transformation
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-19 20:00 EST
G. Diniz, F. D. Picoli, M. P. Lenzarini
The Sommerfeld-Watson transformation is a powerful mathematical technique widely used in physics to simplify summations over discrete quantum numbers by converting them into contour integrals in the complex plane. This method has applications in scattering theory, high-energy physics, quantum field theory, and electrostatics. A lesser-known but significant use is in the analytical diagonalization of specific Hamiltonians in condensed matter physics, such as the Fermi gas Hamiltonian and the single-impurity Anderson model with vanishing Coulomb repulsion. These models are used to describe important phenomena like conductance in metals, x-ray photoemission, and aspects of the Kondo problem. In this work, we provide a comprehensive explanation of the Sommerfeld-Watson transformation and its application in diagonalization procedures for these models, using modern notation to enhance clarity for new students. The analytical results were validated against the numerical diagonalization, showing excellent agreement. Furthermore, we extend the presented method to a more generalized non-interacting single-impurity Anderson model with variable couplings and arbitrary band dispersion. The procedure presented here successfully achieved the analytical diagonalization of this more complex model, providing a unified solution that encompasses simpler cases. To our knowledge, this general solution has not been previously reported.
Strongly Correlated Electrons (cond-mat.str-el), Other Condensed Matter (cond-mat.other)
Abnormal Normal State and Pressure-driven Reentrant Superconductivity in the Heavy \(d\)-electron Superconductor Rh\(_{17}\)S\(_{15}\)
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-19 20:00 EST
Xiaofeng Xu, J. Y. Nie, C. Q. Xu, Z. M. Zhu, Xiangzhuo Xing, Y. L. Huang, C. T. Zhang, N. Zuo, C. C. Zhao, Z. Y. Zhang, W. Zhou, W. H. Jiao, S. Xu, Q. Zhang, Zhu-An Xu, X. B. Liu, Dong Qian, Shiyan Li
Superconductivity beyond the conventional Bardeen-Cooper-Schrieffer (BCS) framework often emerges out of a normal state that is accompanied by exotic magnetism and thereby displays many exceptional transport and thermodynamic properties. Here we report that the normal state of the heavy \(d\)-electron superconductor Rh\(_{17}\)S\(_{15}\) is characterized by a weak that persists up to room temperature. We show that the broad hump in its resistivity likely results from the Kondo interaction of the conduction electrons with this novel magnetism. By applying pressure, superconductivity is fully suppressed first. In the high-pressure regime, however, we observe a second dome of superconductivity with its maximum \(T_c\) greater than the ambient pressure value, highlighting the possible superconductivity in this heavy \(d\)-electron sulfide.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
4 figures
Non-ergodic Phase Transition in the Global Hysteresis of the Frustrated Magnet DyRu2Si2
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-19 20:00 EST
S. Yoshimoto, Y. Tabata, T. Waki, H. Nakamura
Some frustrated magnets exhibit a huge hysteresis called "global hysteresis (GH)", where the magnetic plateaus appearing in the increasing field process are skipped in the decreasing field process from the high magnetic field state. In this paper, we focused on the frustrated magnet DyRu2Si2 and measured magnetization relaxations from two plateau states inside the GH loop, the phases III and IV, and investigated the phase transitions into them. As a result of the relaxation measurements, no relaxation is observed in the phase III, whereas long-time relaxations of more than 105 sec are observed at the phase IV plateau. Moreover, a Mpemba-effect-like relaxation phenomenon where the relaxation from an initial state prepared in the zero-field-cooled condition overtakes that from an initial state prepared in the field-cooled condition is observed. These results indicate that the phase IV is the non-ergodic state with a complex free-energy landscape with multiple local minima, while the phase III has a simple free energy structure. Therefore, the III-IV phase transition is considered to be the ergodic to non-ergodic phase transition. Although this type of phase transition typically occurs in random glassy systems, the phase IV in DyRu2Si2 has a regular long-range ordered magnetic structure and yet exhibits non-ergodic properties, which is highly nontrivial. Our findings open the possibility of observing non-ergodic states in frustrated magnets with regular long-range orders.
Strongly Correlated Electrons (cond-mat.str-el)
15 pages, 15 figures
Disordered ground state in the 3D face-centred frustrated spin-\(\frac{5}{2}\) system MnSn(OH)\(_\text{6}\)
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-19 20:00 EST
Kaushick K. Parui, Anton A. Kulbakov, Ellen Häußler, Nikolai S. Pavlovskii, Aswathi Mannathanath Chakkingal, Maxim Avdeev, Roman Gumeniuk, Sergey Granovsky, Alexander Mistonov, Sergei A. Zvyagin, Thomas Doert, Dmytro S. Inosov, Darren C. Peets
Frustrated magnetism in face-centred cubic (fcc) magnetic sublattices remains underexplored but holds considerable potential for exotic magnetic behaviour. Here we report on the crystal structure, magnetic and thermodynamic properties of the \(A\)-site-vacant double hydroxide perovskite MnSn(OH)\(_6\). Despite dominant antiferromagnetic interactions among Mn\(^{2+}\) moments, evidenced by a negative Curie-Weiss temperature, the lack of a sharp thermodynamic transition down to 350\(\,\)mK implies the absence of long-range magnetic order. However, a broad hump in the specific heat at 1.6\(\,\)K suggests short-range correlations. Neutron diffraction at low temperatures confirms the presence of three-dimensional (3D) antiferromagnetic correlations, manifested as diffuse magnetic scattering with a correlation length \(\xi = 24.66\,\)Å and magnetic propagation vectors \(\mathbf{k}=(\frac{1}{2}\,\frac{1}{2}\,\frac{1}{2})\) and \((0\,0.625\,0)\) at 20\(\,\)mK.
Strongly Correlated Electrons (cond-mat.str-el)
9.5 pages, 5 figures. CIF files included as arXiv ancillary files
Nonmonotonic concentration dependence of the self-diffusion coefficient of surfactants in wormlike micellar solutions
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-19 20:00 EST
Yusuke Koide, Takato Ishida, Takashi Uneyama, Yuichi Masubuchi
We investigate the concentration dependence of surfactant diffusion in wormlike micellar solutions using dissipative particle dynamics simulations. The simulations show that the self-diffusion coefficient of surfactants exhibits a nonmonotonic dependence on the surfactant concentration, as observed in previous experiments. We quantitatively reveal that this nonmonotonic behavior results from the competition between micellar center-of-mass diffusion and surfactant diffusion within micelles by decomposing the mean-square displacement of surfactants into the corresponding contributions. Furthermore, our detailed analyses demonstrate how the competition between the two diffusion mechanisms is governed by the aggregation number distribution, the dynamics of individual surfactants and micelles, and the kinetics of micellar scission and recombination.
Soft Condensed Matter (cond-mat.soft)
Fundamental Origin of Viscosity in 2D Simple Liquids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-19 20:00 EST
Dong Huang, Shaoyu Lu, Chen Liang, Matteo Baggioli, Yan Feng
Shear viscosity plays a fundamental role in liquid dynamics from heavy-ion collisions to biological processes. Still, its physical origin at the individual particle kinetic level remains strongly debated. In this work, we systematically investigate the shear viscosity (\(\eta\)) of two-dimensional (2D) simple liquids using computer simulations of Lennard-Jones, Yukawa, and one-component plasma systems. By combining Frenkel's liquid description, consisting of solid-like quasi-harmonic vibrations interrupted by thermally activated hops, with the concept of lifetime of local atomic connectivity \(\tau_{LC}\), we find a surprisingly simple formula for the kinematic viscosity that is solely determined by \(\tau_{LC}\) and the average kinetic particle speed \(\bar{v}_p\). The derived analytical expression provides a direct link between macroscopic and microscopic dynamics, which shows excellent agreement with the simulation data in all the 2D liquids considered. Moreover, it is discovered that, \(\tau_{LC}\) in 2D liquids is universally determined by the effective potential difference between the first peak and valley of the pair correlation function, implying a direct connection between macroscopic shear transport and microscopic structure. Finally, we demonstrate that the characteristic length scale \(l_p= \bar{v}_p \tau_{LC}\), which governs the macroscopic shear viscosity, aligns with the elastic length-scale that defines the propagation limit of collective shear waves in liquids. These findings establish that shear viscosity in 2D liquids arises from the diffusive transport of average particle momentum across the elastic length scale. Moreover, they highlight that shear dynamics are fundamentally governed by localized configurational excitations within the atomic connectivity network.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci), Statistical Mechanics (cond-mat.stat-mech)
v1: comments welcome
Ultrasound measurement technique for the single-turn-coil magnets
New Submission | Other Condensed Matter (cond-mat.other) | 2025-02-19 20:00 EST
T. Nomura, A. Hauspurg, D. I. Gorbunov, A. Miyata, E. Schulze, S. A. Zvyagin, V. Tsurkan, Y. H. Matsuda, Y. Kohama, S. Zherlitsyn
Ultrasound is a powerful means to study numerous phenomena of condensed-matter physics as acoustic waves couple strongly to structural, magnetic, orbital, and charge degrees of freedom. In this paper, we present such technique combined with single-turn coils (STC) which generate magnetic fields beyond 100 T with the typical pulse duration of 6 us. As a benchmark of this technique, the ultrasound results for MnCr2S4, Cu6[Si6O18]6H2O, and liquid oxygen are shown. The resolution for the relative sound-velocity change in the STC is estimated as Delta v/v~10^-3, which is sufficient to study various field-induced phase transitions and critical phenomena.
Other Condensed Matter (cond-mat.other)
8 pages, 6 figures
Rev. Sci. Instrum. 92, 063902 (2021)
Instability of a fluctuating biomimetic membrane driven by an applied uniform DC electric field
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-19 20:00 EST
Zongxin Yu, Shuozhen Zhao, Michael J. Miksis, Petia M. Vlahovska
The linear stability of a lipid membrane under a DC electric field, applied perpendicularly to the interface, is investigated in the electrokinetic framework, taking account to the dynamics of the Debye layers formed near the membrane. The perturbed charge in the Debye layer redistributes and destabilizes the membrane via electrical surface stress interior and exterior to the membrane. The instability is suppressed as the difference in the electrolyte concentration of the solutions separated by the membrane increases, due to a weakened base state electric field near the membrane. This result contrasts with the destabilizing effect predicted using the leaky dielectric model in cases of asymmetric conductivity. We attribute this difference to the varying assumptions about the perturbation amplitude relative to the Debye length, which result in different regimes of validity for the linear stability analysis within these two frameworks.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
Bacterial swimming and accumulation on endothelial cell surfaces
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-19 20:00 EST
Xin-Xin Xu, Yangguang Tian, Yuhe Pu, Bingchen Che, Hao Luo, Yanan Liu, Yan-Jun Liu, Guangyin Jing
Flagellar-driven locomotion plays a critical role in bacterial attachment and colonization of surfaces, contributing to the risks of contamination and infection. Tremendous attempts to uncover the underlying principles governing bacterial motility near surfaces have relied on idealized assumptions of surrounding inorganic boundaries. However, in the context of living systems, the role of cells from tissues and organs becomes increasingly critical, particularly in bacterial swimming and adhesion, yet it remains poorly understood. Here, we propose using biological surfaces composed of vascular endothelial cells to experimentally investigate bacterial motion and interaction behaviors. Our results reveal that bacterial trapping observed on inorganic surfaces is counteractively manifested with reduced radii of circular motion on cellular surfaces, while with two distinct modes of bacterial adhesion: tight adhesion and loose adhesion. Interestingly, the presence of living cells enhances bacterial surface enrichment, and imposed flow intensifies this accumulation via bias-swimming effect. These results surprisingly indicate that physical effects remain the dominant factor regulating bacterial motility and accumulation at the single-cell layer level in vitro, bridging the gap between simplified hydrodynamic mechanisms and complex biological surfaces, with relevance to biofilm formation and bacterial contamination.
Soft Condensed Matter (cond-mat.soft)
5 figures
Study of amorphous alumina coatings for next-generation nuclear reactors: hightemperature in-situ and post-mortem Raman spectroscopy and X-ray diffraction
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-19 20:00 EST
Magdalena Gaweda, Piotr Jelen, Agata Zaborowska, Ryszard Diduszko, Lukasz Kurpaska
The present work focuses on the investigation of the thermal stability and structural integrity of amorphous alumina coatings intended for use as protective coatings on cladding tubes in Generation IV nuclear reactors, specifically in the Lead-cooled Fast Reactor (LFR) type. Hightemperature Raman spectroscopy and high-temperature X-ray diffraction analyses were carried out up to 1050 C on a 5 um coating deposited by the pulsed laser deposition (PLD) technique on a 316L steel substrate. The experiments involved the in-situ examination of structural changes in the material under increasing temperature, along with ex-situ Raman imaging of the surface and cross-section of the coating after thermal treatments of different lengths. As it was expected, the presence of alpha-alumina was detected with the addition of other polymorphs, gamma- and theta-Al2O3, found in the material after longer high-temperature exposure. The use of two structural analysis methods and two lasers excitation wavelengths with Raman spectroscopy allowed us to detect all the mentioned phases despite different mode activity. Alumina analysis was based on the emission spectra, while substrate oxidation products were identified through the structural bands. The experiments depicted a dependence of the phase composition of oxidation products and alumina's degree of crystallization on the length of the treatment. Nevertheless, the observed structural changes did not occur rapidly, and the coating's integrity remained intact. Moreover, oxidation signs occurred locally at temperatures exceeding the LFR reactor's working temperature, confirming the material's great potential as a protective coating in the operational conditions of LFR nuclear reactors.
Materials Science (cond-mat.mtrl-sci)
Reversibly Strain Engineering and Electric-Field Control of Crystal Symmetry in Multiferroic Oxides
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-19 20:00 EST
Fei Sun, Chao Chen, Deyang Chen, Minghui Qin, Xubing Lu, Xingsen Gao, Christopher T Nelson, Jun-Ming Liu
Multiferroic oxides, such as BiFeO3, have garnered significant attention due to their coupled ferroelectric, magnetic, and elastic properties, offering exciting opportunities for multifunctional device applications. Controlling phase transitions in these materials is critical for tuning their physical properties and achieving desired functionalities. While numerous studies have focused on ferroelectric-ferroelectric transitions at rhombohedral-tetragonal morphotropic phase boundaries, far less attention has been given to the ferroelectric-antiferroelectric phase boundaries. Such systems hold promise for discovering novel physical phenomena, such as reversible phase transitions, enhanced piezoelectricity, and magnetoelectric coupling. In this work, we report a reversible antiferroelectric-to-ferroelectric phase transition in La doped BiFeO3 thin films. By modulating the residual strain via film thickness, an antiferroelectric orthorhombic phase is stabilized within a ferroelectric rhombohedral phase matrix. Under an external electric field, the phase transitions reversibly between these two states. This discovery not only enriches the understanding of orthorhombic-rhombohedral morphotropic phase boundaries but also provides a potential pathway for developing magnetoelectric devices with enhanced functionality.
Materials Science (cond-mat.mtrl-sci)
Roles of Defects and Sb-doping in the Thermoelectric Properties of Full-Heusler Fe2TiSn
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-19 20:00 EST
Ilaria Pallecchi, Daniel I. Bilc, Marcella Pani, Fabio Ricci, Sebastien Lemal, Philippe Ghosez, Daniele Marre'
The potential of Fe2TiSn full-Heusler compounds for thermoelectric applications has been suggested theoretically, but not yet grounded experimentally, due to the difficulty of obtaining reproducible, homogeneous, phase pure and defect free samples. In this work, we study Fe2TiSn1-xSbx polycrystals (x from 0 to 0.6), fabricated by high-frequency melting and long-time high-temperature annealing. We obtain fairly good phase purity, homogeneous microstructure and good matrix stoichiometry. Although intrinsic p-type transport behavior is dominant, n-type charge compensation by Sb doping is demonstrated. Calculations of formation energy of defects and electronic properties carried out in the density functional theory formalism reveal that charged iron vacancies VFe2- are the dominant defects responsible for the intrinsic p-type doping of Fe2TiSn in all types of growing conditions except Fe-rich. Additionally, Sb substitutions at Sn site give rise either to SbSn, SbSn1+ which are responsible for n-type doping and magnetism (SbSn) or to magnetic SbSn1- which act as additional p-type dopants. Our experimental data highlight good thermoelectric properties close to room temperature, with Seebeck coefficients up to 56 microV/K in the x=0.2 sample and power factors up to 4.8x10^-4 W m^-1 K^-2 in the x=0.1 sample. Our calculations indicate the appearance of a pseudogap in Ti-rich conditions and large Sb doping, possibly improving further the thermoelectric properties.
Materials Science (cond-mat.mtrl-sci)
ACS Appl Mater Interfaces 2022, 14, 22, 25722-25730
Effect of laser field and magnetic flux on scattering in graphene quantum dots
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-19 20:00 EST
Mohammed El Azar, Ahmed Bouhlal, Hocine Bahlouli, Ahmed Jellal
We show how Dirac electrons interact with a graphene quantum dots (GQDs) when exposed to both a magnetic flux and circularly polarized light. After obtaining the solutions of the energy spectrum, we compute the scattering coefficients. These allow us to show how efficiently the electrons diffuse and how their probability density is distributed in space. Our results show that light polarization is key in controlling electron scattering. It affects electron localization near the GQDs and the strength of the scattering coefficients. We also investigate how light intensity and magnetic flux affect the formation of quasi-bound states. In addition, the electrostatic potential reduces the density of scattering states and fine-tunes the interaction between electrons and the quantum dot. This research improves our understanding of electron behavior in graphene nanostructures and suggests new ways to control electronic states at the quantum level.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
13 pages, 8 figures
Stability of Floquet sidebands and quantum coherence in 1D strongly interacting spinless fermions
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-19 20:00 EST
Karun Gadge, Salvatore R. Manmana
For strongly correlated quantum systems, fundamental questions about the formation and stability of Floquet-Bloch sidebands (FBs) upon periodic driving remain unresolved. Here, we investigate the impact of electron-electron interactions and perturbations in the coherence of the driving on the lifetime of FBs by directly addressing these questions in time-dependent single-particle spectral functions. Using exact diagonalization (ED) and matrix product states (MPS), we find for a chain of interacting spinless fermions that high-frequency driving leads to long-lived FBs of the full many-body excitation continuum, accompanied by in-gap modes related to mobile domain walls. Conversely, in the low-frequency regime and in the presence of noise, heating dominates, resulting in a significant loss of quantum coherence. This is further elucidated by the behaviour of real-space single-particle propagators, of the energy gain, and of the momentum distribution function, which is related to a quantum Fisher information that is directly accessible by spectroscopic measurements.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
Main text and supplemental material
Stabilization of magnetic bubbles in [Ni/Co]\(_{n}\) multilayers on an oxygen-reconstructed Nb(110) surface via an ultra-thin Cu interlayer
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-19 20:00 EST
Ahmad Dibajeh, Cameron W. Johnson, Andreas K. Schmid, Roberto Lo Conte
Magnetic thin films hosting topological spin textures, such as magnetic skyrmions, hold high potential for breakthroughs in the field of spintronics, due to good scalability and energy efficiency. Novel computational architectures such as memory-in-logic devices rely on material platforms able to host those topological spin textures. Furthermore, recently proposed designs of novel quantum information technologies are based on heterostructures where topological spin textures are in direct proximity to a superconducting layer. Here, we demonstrate the stabilization of out-of-plane magnetic bubbles in highly ordered [Ni/Co]\(_{n}\) multilayers on a Nb(110) single crystal. This is achieved without the need for removal of the well-known Nb(110)-oxide surface reconstruction, due to the introduction of a one-atom-thick Cu interlayer in between the Nb substrate and the magnetic multilayer. The Cu interlayer generates a well-ordered hexagonal surface, which is key for the epitaxial growth of the [Ni/Co]\(_{n}\) multilayers hosting the desired out-of-plane anisotropy. The magnetic ground state of the prepared material stacks is directly imaged via spin-polarized low energy electron microscopy (SPLEEM), revealing the presence of magnetic bubble domains with lateral sizes as small as 450 nm.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
A thin film source in a solid-state diffusion experiment: CoO on SrTiO3
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-19 20:00 EST
Qian Ma, Jan Erik Rybak, Natalie Jacqueline Ottinger, Timo Kassubek, Jörg Hoffmann, Karl-Michael Weitzel, Cynthia A. Volkert, Christian Jooss
To realize a chemical diffusion experiment for simple quantitative analysis of one-dimensional diffusion profiles requires the fabrication of a planar and chemically sharp interface between two phases, one serving as the diffusion source and the other as the material to be studied. We demonstrate a thin film source on top of single crystals or epitaxial films for the example of cobalt (II) oxide (CoO) grown on top of SrTiO3 (STO) by ion beam sputtering. After deposition at room temperature, a nanocrystalline film with flat and chemically sharp interface is present. Diffusion annealing leads to a partial formation of the Co3O4 phase and recrystallization accompanied by a strong increase of the surface and the interface roughness. We report the conditions, where compact and stable CoO layers with flat interface can be maintained, serving as a constant source for Co diffusion. Exemplarily, the formation of a Co-diffusion profile is demonstrated after annealing of 240 h at 1163 K and comparatively studied by using three different methods: Energy dispersive x-ray spectroscopy (EDX) in a transmission electron microscope (TEM), atom probe tomography (APT) and time of flight secondary ion mass spectroscopy (TOF SIMS). Local and rather macroscopic concentration profiling do well agree within error.
Materials Science (cond-mat.mtrl-sci)
Machine learning exploration of topological polarization pattern in hexagonal boron nitride moiré superlattice
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-19 20:00 EST
Jun-Ding Zheng, Cheng-Shi Yao, Song-Chuan Zhou, Yu-Ke Zhang, Zhi-Qiang Bao, Wen-Yi Tong, Jun-Hao Chu, Chun-Gang Duan
Twisted moiré supercells, which can be approximated as a combination of sliding bilayers and constitute various topologically nontrivial polarization patterns, attract extensive attention recently. However, because of the excessive size of the moiré supercell, most studies are based on effective models and lack the results of first-principles calculation. In this work, we use machine learning to determine the topological structure of the polarization pattern in twisted and strained bilayer of hexagonal boron nitride (h-BN). We further confirm that the topological pattern can be effectively modulated by the vertical electric field and lattice mismatch. Finally, local polarization also exists in the antiparallel stacked h-BN twisted and strained bilayers. Our work provides a detailed study of the polarization pattern in the moiré superlattice, which we believe can facilitate more research in moiré ferroelectricity, topological physics, and related fields.
Materials Science (cond-mat.mtrl-sci)
Probing dielectric breakdown in Mott insulators through current oscillations
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-19 20:00 EST
Joan Triadú-Galí, Artur Garcia-Saez, Bruno Juliá-Díaz, Axel Pérez-Obiol
We investigate the dielectric breakdown of mesoscopic Mott insulators, a phenomenon where a strong electric field destabilizes the insulating state, resulting in a transition to a metallic phase. Using the Landau-Zener formalism, which models the excitation of a two-level system, we derive a theoretical expression for the threshold value of the field. To validate our predictions, we present an efficient protocol for estimating the charge gap and threshold field via non-equilibrium current oscillations, overcoming the computational limitations of exact diagonalization. Our simulations demonstrate the accuracy of our theoretical formula for systems with small gaps. Moreover, our findings are directly testable in ultracold atomic experiments with ring geometries and artificial gauge fields, as our method uses measurable quantities and relies on already available technologies. This work aims to bridge the gap between theoretical models and experimentally realizable protocols, providing tools to explore non-equilibrium mesoscopic phenomena in strongly correlated quantum systems.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Gases (cond-mat.quant-gas)
22 pages, 9 figures
2D Layered Heterojunctions for Photoelectrocatalysis
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-19 20:00 EST
Mengjiao Wang, Michal Langer, Roberto Altieri, Matteo Crisci, Silvio Osella, Teresa Gatti
Two-dimensional (2D) layered nanomaterials heterostructures, arising from the combination of 2D materials with other low-dimensional species, feature large surface area to volume ratio, which provides a high density of active sites for catalytic ap-plications and in particular for (photo)electrocatalysis (PEC). Meanwhile, their unique electronic band structure and high electrical conductivity enable efficient charge transfer (CT) between the active material and the substrate, which is essential for catalytic activity. In recent years, researchers have demonstrated the potential of a range of 2D material interfaces, such as graphene, graphitic carbon nitride (g-C3N4), metal chalcogenides (MCs), and MXenes, for (photo)electrocatalytic applica-tions. For instance, MCs such as MoS2 and WS2 have shown excellent catalytic activity for hydrogen evolution, while gra-phene and MXenes have been used for the reduction of carbon dioxide to higher value chemicals. However, despite their great potential, there are still major challenges that need to be addressed in order to fully realize the potential of 2D materials for PEC. For example, their stability under harsh reaction conditions, as well as their scalability for large-scale production are important factors to be considered. Generating heterojunctions (HJs) by combining 2D layered structures with other na-nomaterials is a promising method to improve the photoelectrocatalytic properties of the former. In this review, we inspect thoroughly the recent literature, to demonstrate the significant potential that arises from utilizing 2D layered heterostructures in PEC processes across a broad spectrum of applications, from energy conversion and storage to environmental remediation. With the ongoing research and development, it is likely that the potential of these materials will be fully expressed in the near future.
Materials Science (cond-mat.mtrl-sci)
ACS Nano 2024 18, 9245-9284
Relaxation dynamics of a quantum spin coupled to a topological edge state
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-19 20:00 EST
Qiyu Liu, Christoph Karrasch, Dante Marvin Kennes, Roman Rausch
A classical impurity spin coupled to the spinful Su-Schrieffer-Heeger (SSH) chain is known to exhibit complex switching dynamics with incomplete spin relaxation. Here, we study the corrections that result from a full quantum treatment of the impurity spin. We find that in the topologically trivial case, the quantum spin behaves similarly to the classical one due to the absence of the Kondo effect for the trivial insulator. In the topological case, the quantum spin is significantly less likely to relax: It can be stuck at a pre-relaxation plateau with a sizable deviation from the expected relaxed value, and there is a large parameter regime where it does not relax at all but features an anomalously large Larmor frequency. Furthermore, we find an additional quantum effect where the pre-relaxation plateau can be hyperpolarized, i.e., the spin is stuck at a polarization value larger than the ground-state expectation value. This is possible due to the (incomplete) Kondo screening of the quantum spin, which is absent in the classical case. Our results are obtained via the ground state density matrix renormalization group algorithm and the time-dependent variational principle, where the charge-SU(2) symmetry of the problem was exploited. Furthermore, we introduce and benchmark a method to predict the dynamics from the given numerical data based on the sparse identification of nonlinear dynamics (SINDy). This allows us to prolong the simulation timescale by a factor of 2.5, up to a maximal time of \(10^3\) inverse hoppings.
Strongly Correlated Electrons (cond-mat.str-el)
No time for surface charge: how bulk conductivity hides charge patterns from KPFM in contact-electrified surfaces
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-19 20:00 EST
Felix Pertl, Isaac C.D. Lenton, Tobias Cramer, Scott Waitukaitis
Kelvin probe force microscopy (KPFM) is a powerful tool for studying contact electrification, using an tiny tip to image voltages caused by transferred charge. It has been used in stationary studies focused on finding patterns (e.g. heterogeneity) in transferred charge, but also in dynamic studies aimed at understanding how charge escapes. Here, we show that the charge dynamics in all but the very best insulators are too fast for patterns found in stationary studies to be meaningful. Using a custom-built system, we are able to quickly (~30 s) transfer samples from our contact-charging apparatus to the atomic force microscopy (AFM). For materials at the lower end of `good insulators', we see potential decay that is shorter than the timescale of a typical KPFM scan (~10 minutes). We develop a minimal model to explain this decay based on bulk conductivity, and show that the measured timescale increases with the prediction from this model. To rule out surface conductivity, we perform additional experiments with the macroscopic method of scanning Kelvin probe microscopy. Our results highlight an important but widely overlooked consideration for dynamic vs. stationary studies in contact-electrified surfaces, and suggest that some patterns observed in the latter, e.g. charge heterogeneity, are not as widespread as previously thought.
Soft Condensed Matter (cond-mat.soft)
Realization of strain induced multiple topological phases in Cu\(_2\)SnS\(_3\): An \(ab\)-\(initio\) study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-19 20:00 EST
Prakash Pandey, Sudhir K. Pandey
The search of multiple topological phases (TPs) and their transitions by tuning different parameters through chemical substitutions, electric field, magnetic field, strain and Floquet engineering, etc has garnered a widespread attention in recent time. In spite of great effort, the observations of multiple TPs in a single material and multiple TP transitions in the presence of one parameter remain elusive. Here we demonstrate the presence of multiple TPs and their transitions with uniaxial compressive strain (UCS) in orthorhombic Cu\(_2\)SnS\(_3\) by using \(state\)-\(of\)-\(the\)-\(art\) \(ab\)-\(initio\) calculations. In the absence of spin-orbit coupling (SOC), the Cu\(_2\)SnS\(_3\) exhibits a single (type-II) nodal-ring and in the presence of SOC, it hosts Weyl phase with seven Weyl points (three at \(\Gamma\) and four at general positions) along with nodal arcs. On the application of UCS, it remains type-II nodal-ring \(<5.5\)%, which further evolves into type-III nodal-ring for \(5.5\% \leq\) UCS \(<5.6\)%. Interestingly, at 5.6% of UCS, it shows Weyl phase with four Weyl nodes even in the absence of SOC. All the above-mentioned seven Weyl points persist below \(5\)% of UCS. For 5% \(\leq\) UCS \(<5.6\)%, four Weyl points (at general positions) disappear and nodal-arcs remain intact in all the studied range of UCS. The TPs observed in the absence of SOC appears to arise due to the presence of strain driven topological flat band, which is typically reported to be seen in kagome and Lieb lattices.
Materials Science (cond-mat.mtrl-sci)
Form and function in biological filaments: A physicist's review
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-19 20:00 EST
Jan Cammann, Hannah Laeverenz-Schlogelhofer, Kirsty Y. Wan, Marco G. Mazza
Nature uses elongated shapes and filaments to build stable structures, generate motion, and allow complex geometric interactions. In this Review, we examine the role of biological filaments across different length scales. From the molecular scale, where cytoskeletal filaments provides a robust but dynamic cellular scaffolding, over the scale of cellular appendages like cilia and flagella, to the scale of filamentous microorganisms like cyanobacteria which are among the most successful genera on Earth, and even to the scale of elongated animals like worms and snakes, whose motility modes inspire robotic analogues. We highlight the general mechanisms that couple form and function. Physical principles, such as classical elasticity and the non-reciprocity of active matter can be used to trace unifying themes linking these systems spanning about six orders of magnitude in length.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
Antisymmetry rules of response properties in certain chemical spaces
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-19 20:00 EST
Takafumi Shiraogawa, Simon León Krug, Masahiro Ehara, O. Anatole von Lilienfeld
Understanding chemical compound space (CCS), a set of molecules and materials, is crucial for the rational discovery of molecules and materials. Concepts of symmetry have recently been introduced into CCS to account for near degeneracies and differences in electronic energies between iso-electronic materials. In this work, we present approximate relationships of response properties based on a first-principles view of CCS. They have been derived from perturbation theory and antisymmetry considerations involving nuclear charges. These rules allow approximate predictions of relative response properties of pairs of distinct compounds with opposite nuclear charge variations from a highly symmetric reference material, without the need for experiments or quantum chemical calculations of each compound. We numerically and statistically verified these rules for electric and magnetic response properties (electric dipole moment, polarizabilities, hyperpolarizabilities, and magnetizabilities) among charge-neutral and iso-electronic BN-doped polycyclic aromatic hydrocarbon derivatives of naphthalene, anthracene, and pyrene. Our analysis indicates that, despite their simplicity, antisymmetry rule-based predictions are remarkably accurate, enabling dimensionality reduction of CCS. Response properties in alchemical perturbation density functional theory were investigated to clarify the origin of this predictive power. The origin of this predictive power was clarified based on alchemical perturbation density functional theory.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
34 pages, 14 figures
Ultrafast annealing process of MTJ using hybrid microwave annealing
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-19 20:00 EST
Ming-Chun Hsu, Fan-Yun Chiu, Wei-Chi Aeneas Hsu, Chang-Shan Shen, Kun-Ping Huang, Tsun-Hsu Chang
This paper discovers that the magnetic tunnel junction (MTJ) structure is successfully magnetized with hybrid microwave annealing, confirmed by the tunneling magnetoresistance (TMR) and Coercivity (Hc) results. Hybrid microwave annealing can transform CoFeB into a single crystal and form the Fe-O bond at the interface between CoFeB and MgO without adding an extra magnet. The annealing time is significantly reduced from the original 120 minutes to just 1 minute, allowing for rapid low-temperature annealing of the MTJ structure. The TEM results are used to determine the change in the lattice structure of CoFeB from amorphous to a single crystal, and the EELS result indicates the diffusion distribution of atoms in the MTJ structure. This hybrid annealing process can save a significant amount of fabrication time and is an energy-efficient alternative to the current fabrication process of MRAM.
Materials Science (cond-mat.mtrl-sci)
3 pages, 5 figures
Anomalous exchange correlation of quasiparticles with entangled Nambu spinors
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-19 20:00 EST
Entanglement of spin degree of freedom can drastically alter the orbital exchange symmetry of electrons, switching their bunching and antibunching behaviors and the resultant current correlations in the Hanbury-Brown-Twiss interferometry. Here, we investigate the exchange correlation of quasiparticles with entanglement encoded in the Nambu spinors, or the electron-hole degree of freedom. In contrast to the conventional correspondence between spin entanglement and current correlation, we find that singlet (triplet) entanglement of Nambu spinors results in suppressed (enhanced) current correlation. This effect arises because the charge degree of freedom itself encodes the entanglement. We propose implementing this phenomenon in the edge states of a quantum Hall system, where the entangled states of the Nambu spinors can be continuously tuned by gate voltages. Our study reveals a novel relationship between entanglement and charge correlations, offering an effective approach for detecting entanglement of Nambu spinors.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Enhancement of persistent current in a non-Hermitian disordered ring
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-19 20:00 EST
Suparna Sarkar, Soumya Satpathi, Swapan K. Pati
We have studied the Aharonov-Bohm flux-induced magnetic response of a disordered non-Hermitian ring. The disorder is introduced through an on-site quasiperiodic potential described by the Aubry-André-Harper (AAH) model, incorporating a complex phase that renders the model non-Hermitian. Our findings reveal that this form of non-Hermiticity enhances the persistent current, without requiring hopping dimerization. We explore both non-interacting and interacting scenarios. In the former, we examine spinless fermions, while in the latter, we consider fermions with Hubbard interactions. The Non-Hermitian phase induces both the real and imaginary components of the current. We thoroughly analyze the energy eigenspectrum, ground state energy, and persistent current in both real and imaginary spaces for various system parameters. Our primary goal is to investigate the combined effects of non-Hermiticity and disorder strength on persistent currents. We find an enhancement in both the real and imaginary components of the persistent current with increasing disorder strength, as well as the non-Hermiticity, up to a critical value. Furthermore, we observe an enhancement in persistent current in the presence of Hubbard correlation. Our findings may provide a new route to get nontrivial characteristics in persistent current for a special type of non-Hermitian systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Effect of Annealing on Al Diffusion and its Impact on the Properties of Ga\(_2\)O\(_3\) Thin Films Deposited on c-plane Sapphire by RF Sputtering
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-19 20:00 EST
Ana Sofia Sousa, Duarte M. Esteves, Tiago T. Robalo, Mário S. Rodrigues, Luís F. Santos, Katharina Lorenz, Marco Peres
Gallium oxide is a wide-bandgap semiconductor which has been steadily growing in popularity due to its ultra-wide bandgap, suitability for harsh environments and distinctive opto-electrical properties. Notable applications include deep-UV photodetectors, low loss waveguides or even transparent solar cells. RF sputtering stands out among possible techniques for the epitaxial deposition of Ga\(_{2}\)O\(_{3}\) thin films with high quality and at a low cost. By using sapphire substrates, and through thermal annealing, we can form a \(\beta\)-(Al\(_{x}\)Ga\(_{1-x}\))\(_{2}\)O\(_{3}\) alloy by Al diffusion, which has tunable opto-electrical properties such as the bandgap and breakdown electric field. In this work, techniques such as X-ray diffraction, Rutherford backscattering spectrometry, Raman spectroscopy, atomic force microscopy and optical transmission are used to determine the optical properties, morphology and composition of Ga\(_{2}\)O\(_{3}\) deposited and annealed thin films. To explore the formation of the \(\beta\)-(Al\(_{x}\)Ga\(_{1-x}\))\(_{2}\)O\(_{3}\) alloy, annealing was performed at variable temperature, in ambient air. It was determined that the bandgap can indeed be tuned between 4.85 and 5.30 eV by varying the annealing temperature, corresponding to an Al content between 0$-$68.5.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Orientation Dependent Resistivity Scaling in Mesoscopic NbP Crystals
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-19 20:00 EST
Gianluca Mariani, Federico Balduini, Nathan Drucker, Lorenzo Rocchino, Vicky Hasse, Claudia Felser, Heinz Schmid, Cezar Zota, Bernd Gotsmann
The scaling of Si transistor technology has resulted in a remarkable improvement in the performance of integrated circuits over the last decades. However, scaled transistors also require reduced electrical interconnect dimensions, which lead to greater losses and power dissipation at circuit level. This is mainly caused by enhanced surface scattering of charge carriers in copper interconnect wires at dimensions below 30 nm. A promising approach to mitigate this issue is to use directional conductors, i.e. materials with anisotropic Fermi surface, where proper alignment of crystalline orientation and transport direction can minimize surface scattering. In this work, we perform a resistivity scaling study of the anisotropic semimetal NbP as a function of crystalline orientation. We use here focused ion beam to pattern and scale down NbP crystallites to dimensions comparable to the electron scattering length at cryogenic temperatures. The experimental transport properties are correlated with the Fermi surface characteristics through a theoretical model, thus identifying the physical mechanisms that influence the resistivity scaling of anisotropic conductors. Our methodology provides an effective approach for early evaluation of anisotropic materials as future ultra-scalable interconnects, even when they are unavailable as epitaxial films.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
18 pages, 3 figures
Delta-function-potential junctions with quasiparticles occupying tilted bands with quadratic-in-momentum dispersion
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-19 20:00 EST
We continue our explorations of the transport characteristics in junction-configurations comprising semimetals with quadratic band-crossings, observed in the bandstructures of both two- and three-dimensional materials. Here, we consider short potential barriers/wells modelled by delta-function potentials. We also generalize our analysis by incorporating tilts in the dispersion. Due to the parabolic nature of the spectra, caused by quadratic-in-momentum dependence, there exist evanescent waves, which decay exponentially as we move away from the junction represented by the location of the delta-function potential. Investigating the possibility of the appearance of bound states, we find that their energies appear as pairs of \(\pm |E_b |\), reflecting the presence of the imaginary-valued wavevectors at both positive and negative values of energies of the propagating quasiparticles.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
follow-up paper of arXiv:2502.06265
Fabrication and characterization of bimetallic silica-based and 3D-printed active colloidal cubes
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-19 20:00 EST
Silvana A. Caipa Cure, Daniela J. Kraft
Simulations on self-propelling active cubes reveal interesting behaviors at both the individual and the collective level, emphasizing the importance of developing experimental analogs that allow to test these theoretical predictions. The majority of experimental realizations of active colloidal cubes rely on light actuation and or magnetic fields to have a persistent active mechanism, and lack material versatility. Here we propose a system of active bimetallic cubes whose propulsion mechanism is based on a catalytic reaction and study their behavior. We realize such a system from synthetic silica cuboids and 3D printed micro cubes, followed by the deposition of gold and platinum layers on their surface. We characterize the colloids dynamics for different thicknesses of the gold layer at low and high hydrogen peroxide concentrations. We show that the thickness of the base gold layer has only a minor effect on the self propulsion speed and in addition induces a gravitational torque which leads to particles with a velocity director pointing out of the plane thus effectively suppressing propulsion. We find that a higher active force can remedy the effects of torque, resulting in particle orientations that are favorable for in plane propulsion. Finally, we use 3D printing to compare our results to cubes made from a different material, size and roundness, and demonstrate that the speed scaling with increasing particle size originates from the size-dependent drag. Our experiments extend fabrication of active cubes to different materials and propulsion mechanisms and highlight that the design of active particles with anisotropic shapes requires consideration of the interplay between the shape and activity to achieve favorable sedimentation and efficient in plane propulsion.
Soft Condensed Matter (cond-mat.soft)
25 pages 4 figures
Evidence for topological origin of large spin-shift current in antiferromagnetic Ti\(_{4}\)C\(_{3}\)
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-19 20:00 EST
Ali Sufyan, Hasan M. Abdullah, J. Andreas Larsson, Alexander C. Tyner
The shift current is a non-linear photocurrent generally associated with the underlying quantum geometry. However, a topological origin for the shift photocurrent in non-centrosymmetric systems has recently been proposed. The corresponding topological classification goes beyond the ten-fold paradigm and is associated with the presence of a reverting Thouless pump (RTP). In this work we examine an antiferromagnetic monolayer within the family of MXenes, Ti\(_{4}\)C\(_{3}\). This material is centrosymmetric, however, magnetic ordering violates inversion symmetry. We demonstrate evidence of an RTP in each spin-sector which has been perturbed, destroying quantization of the invariant. Nevertheless, a giant spin-resolved shift current persists. We further investigate the mid-gap edge states and classification of the system as a fragile topological insulator to which trivial bands have been coupled.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
6 pages, 5 figures
Predictive simulations of the dynamical response of mesoscopic devices
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-19 20:00 EST
Samuel Boutin, Torsten Karzig, Tareq El Dandachi, Ryan V. Mishmash, Jan Gukelberger, Roman M. Lutchyn, Bela Bauer
As the complexity of mesoscopic quantum devices increases, simulations are becoming an invaluable tool for understanding their behavior. This is especially true for the superconductor-semiconductor heterostructures used to build Majorana-based topological qubits, where quantitatively understanding the interplay of topological superconductivity, disorder, semiconductor quantum dots, Coulomb blockade and noise has been essential for progress on device design and interpretation of measurements. In this paper, we describe a general framework to simulate the low-energy quantum dynamics of such complex systems. We illustrate our approach by computing the dispersive gate sensing (DGS) response of quantum dots coupled to topological superconductors. We start by formulating the DGS response as an open-system quantum dynamics problem, which allows a consistent treatment of drive backaction as well as quantum and classical noise. For microscopic quantum problems subject to Coulomb-blockade, where a direct solution in the exponentially large many-body Hilbert space would be prohibitive, we introduce a series of controlled approximations that incorporate ideas from tensor network theory and quantum chemistry to reduce this Hilbert space to a few low-energy degrees of freedom that accurately capture the low-energy quantum dynamics. We demonstrate the methods introduced in this paper on the example of a single quantum dot coupled to a topological superconductor and a microscopic realization of the fermion parity readout setup of Aghaee et al. arXiv:2401.09549 (2024).
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
28 pages, 14 figures
Fluorescent molecular rotor-based polymer materials for local microviscosity mapping in microfluidic channels
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-19 20:00 EST
Dharshana Nalatamby, Florence Gibouin, Maxime Zitouni, Julien Renaudeau, Gérald Clisson, Pierre Lidon, Simon Harrisson, Yaocihuatl Medina-Gonzalez
A viscosity-sensitive monomer consisting of a methacrylate-functionalized julolidone-based molecular rotor (MECVJ) was synthesized and used to obtain viscosity-sensitive polymers (poly(DMA--MECVJ)). The qualitative properties of the molecular rotor were preserved after its inclusion in the new polymer, in particular the effect of the viscosity of the surrounding medium on the fluorescence lifetime of the rotor. By grafting these polymers onto glass slides, viscosity-sensitive surfaces were obtained, showing good robustness in time after successive use and washing. As proof of concept, these surfaces were used to assemble a microfluidic chip capable of mapping viscosity of fluids flowing inside the channel.
Soft Condensed Matter (cond-mat.soft), Applied Physics (physics.app-ph), Chemical Physics (physics.chem-ph)
Bipolaron dynamics in the one-dimensional SSH model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-19 20:00 EST
Filip Marijanović, Yi-Fan Qu, Eugene Demler
Characterizing bipolaron binding, and understanding how it depends on electron-phonon interaction, is crucial to unraveling the nature of emergent many-body states in strongly interacting electron-phonon systems. So far, most studies of bipolarons have been limited to the Holstein model, in which the coupling constant is momentum-independent. The paradigmatic example of momentum-dependent electron-phonon interaction comes from the system in which phonon distortions modify electron hopping, the SSH model. Already individual polarons in the SSH model are richer than the Holstein model counterparts, and feature a phase transition into the finite momentum ground state with increasing electron-phonon interaction. In this paper, we use a variational approach to study bipolarons in the one-dimensional SSH model and discuss their ground state, dispersion, and excitation spectra. We explore the full parameter range of the system, including the adiabatic regime of slow phonons, which was inaccessible to previous theoretical studies. In agreement with earlier studies, we find that in the anti-adiabatic strongly interacting regime, bipolarons have low effective mass. By contrast, in the adiabatic case, we find that increasing electron-phonon interactions results in an exponential increase of the bipolaron mass. We establish the existence of multiple branches of bound excited states of SSH bipolaron and discuss the signatures of these bound states in dynamics. We show that in the anti-adiabatic regime, response functions obey a parity selection rule, that imposes symmetry constraints on the excitation spectra and provides a clear signature of SSH bipolarons.
Strongly Correlated Electrons (cond-mat.str-el)
Artificially creating emergent interfacial antiferromagnetism and its manipulation in a magnetic van-der-Waals heterostructure
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-19 20:00 EST
Xiangqi Wang, Cong Wang, Yupeng Wang, Chunhui Ye, Azizur Rahman, Min Zhang, Suhan Son, Jun Tan, Zengming Zhang, Wei Ji, Je-Geun Park, Kai-Xuan Zhang
Van der Waals (vdW) magnets, with their two-dimensional (2D) atomic structures, provide a unique platform for exploring magnetism at the nanoscale. Although there have been numerous reports on their diverse quantum properties, the emergent interfacial magnetism--artificially created at the interface between two layered magnets--remains largely unexplored. This work presents observations of such emergent interfacial magnetism at the ferromagnet/antiferromagnet interface in a vdW heterostructure. We report the discovery of an intermediate Hall resistance plateau in the anomalous Hall loop, indicative of emergent interfacial antiferromagnetism fostered by the heterointerface. This plateau can be stabilized and further manipulated under varying pressures but collapses under high pressures over 10 GPa. Our theoretical calculations reveal that charge transfer at the interface is pivotal in establishing the interlayer antiferromagnetic spin-exchange interaction. This work illuminates the previously unexplored emergent interfacial magnetism at a vdW interface comprised of a ferromagnetic metal and an antiferromagnetic insulator, and highlights its gradual evolution under increasing pressure. These findings enrich the portfolio of emergent interfacial magnetism and support further investigations on vdW magnetic interfaces and the development of next-generation spintronic devices.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph), Quantum Physics (quant-ph)
Accepted by ACS Nano; 42 pages, 5 main figures, 8 supporting figures
Dielectric-Dependent Range-Separated Hybrid Functional Calculations for Metal Oxides
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-19 20:00 EST
Jiawei Zhan, Marco Govoni, Giulia Galli
Recently, we introduced the screened-exchange range-separated hybrid (SE-RSH) functional to account for spatially dependent dielectric screening in complex materials. The SE-RSH functional has shown good performance in predicting the electronic properties of a large variety of semiconductors and insulators, and of heterogeneous systems composed of building blocks with large dielectric mismatch. Here, we assess the performance of SE-RSH for oxide materials, including antiferromagnetic transition-metal oxides. Through a comparison with other dielectric-dependent hybrid functionals, we demonstrate that SE-RSH yields improved predictions of dielectric constants and band gaps, bringing them into a closer agreement with experimental values. The functional also provides accurate values of magnetic moments of several oxides.
Materials Science (cond-mat.mtrl-sci)
Stripe-like correlations in the cuprates from oxygen NMR
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-19 20:00 EST
Daniel Bandur, Abigail Lee, Stefan Tsankov, Andreas Erb, Juergen Haase
Nuclear magnetic resonance (NMR) of planar oxygen, with its family independent phenomenology, is ideally suited to probe the nature of the quantum matter of superconducting cuprates. Here, with new experiments on La\(_{2-x}\)Sr\(_x\)CuO\(_4\), in particular also at high doping levels, we report on short-range stripe-like correlations between local charge and spin. Their amplitudes at room temperature are nearly independent of doping up to at least \(x=0.30\), only their relative phase slips near \(x=1/4\). Comparisons show the correlations to be generic to the cuprates. Despite the atomic scale length, the variations still resemble the average spin and charge relation, which is not expected from the otherwise simple, apparently metallic behavior, even far into the overdoped regime. Perhaps the phase slip is at the heart of a quantum critical point that demands pseudogap behavior towards lower doping levels in an otherwise strange metal.
Strongly Correlated Electrons (cond-mat.str-el)
16 pages, 4 figures
UV photodetectors and field-effect transistors based on \(β\)-Ga\(_2\)O\(_3\) nanomembranes produced by ion-beam-assisted exfoliation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-19 20:00 EST
Miguel Cardoso Pedro, Duarte Magalhães Esteves, Daniela Rodrigues Pereira, Luís Cerqueira Alves, Chamseddine Bouhafs, Katharina Lorenz, Marco Peres
\(\beta\)-Ga\(_{2}\)O\(_{3}\) nanomembranes, obtained by ion-beam-assisted exfoliation, are used in the fabrication of simple metal-semiconductor-metal (MSM) structures, that are tested as photodetectors (PD) and field-effect transistors (FET). Ti/Au contacts to the membrane are found to be rectifying. However, through thermal treatment in a nitrogen atmosphere for one minute at 500 °C, it is possible to modify this junction to have an ohmic behavior. An MSM PD is studied, reaching a high responsivity of 2.6$\(10\)^{4}$ A/W and a detectivity of 2.4$\(10\)^{14}$ Jones, under 245 nm wavelength illumination, and an applied voltage of 40 V. In order to better understand the behavior of the two junctions, in particular the iono/photocurrent mechanisms, an ion microprobe system is used to assess the response of these PD when excitation is localized in the different regions of the device. Finally, a depletion-mode FET is obtained, with an on/off current ratio of 7.7$\(10\)^{7}$ in the linear regime, at a drain-to-source voltage of 5 V, and with a threshold voltage around $-$3 V. The success in obtaining FET, and most notably, MSM photodetectors, while using a simple device structure, indicates a great potential of the nanomembranes produced by ion-beam-assisted exfoliation for the development of high-performance devices.
Materials Science (cond-mat.mtrl-sci)
23 pages, 9 figures, 2 tables
Spiral multiferroics as a natural skyrmion racetrack
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-19 20:00 EST
Luca Maranzana, Maxim Mostovoy, Naoto Nagaosa, Sergey Artyukhin
Magnetic skyrmions are particle-like spin textures with a nontrivial topology, which ensures their stability even at the nanometer scale. This feature establishes skyrmions as promising information carriers for novel magnetic storage and processing devices, e.g., racetrack memories. However, their fate in various magnetic backgrounds is poorly understood. Here, we show that spiral multiferroics, some of the simplest noncollinear magnets, host bimerons -- skyrmionic textures formed by vortex-antivortex pairs. The bimeron carries magnetic and ferroelectric dipole moments that remarkably depend on its position relative to the spiral background. This property enables precise positioning of the bimeron using a slowly rotating magnetic field, as a \(2\pi\) field rotation shifts the bimeron by one spiral period. We also investigate the non-adiabatic regime that occurs when the rotation frequency exceeds a critical threshold. The results establish a new paradigm in which the background endows topological spin textures with unique functionalities, highlighting spiral multiferroics as a natural skyrmion racetrack.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
14 pages, 3 figures
Generalized Polarization and time-resolved fluorescence provide evidence for different populations of Laurdan in lipid vesicles
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-19 20:00 EST
M. Bacalum, M. Radu, S. Osella, S. Knippenberg, M. Ameloot
The solvatochromic dye Laurdan is widely used in sensing the lipid packing of both model and biological membranes. The fluorescence emission maximum shifts from about 440 nm (blue channel) in condensed membranes (So) to about 490 nm (green channel) in the liquid-crystalline phase (L{}). Although the fluorescence intensity based generalized polarization (GP) is widely used to characterize lipid membranes, the fluorescence lifetime of Laurdan, in the blue and the green channel, is less used for that purpose. Here we explore the correlation between GP and fluorescence lifetimes by spectroscopic measurements on the So and L{} phases of large unilamellar vesicles of DMPC and DPPC. A positive correlation between GP and the lifetimes is observed in each of the optical channels for the two lipid phases. Fluorescence intensities, GP and fluorescence lifetimes depend on the angle between the orientation of the linear polarization of the excitation light and the local normal to the membrane of the optical cross-section. This angular variation depends on the lipid phase and the emission channel. GP and fluorescence intensities in the blue and green channel in So and in the blue channel in L{} exhibit a minimum near 90o. Surprisingly, the intensity in the green channel in L{} reaches a maximum near 90o. The fluorescence lifetimes in the two optical channels also reach a pronounced minimum near 90o in So and L{}, apart from the lifetime in the blue channel in L{} where the lifetime is short with minimal angular variation. To our knowledge, these experimental observations are the first to demonstrate the existence of a bent conformation of Laurdan in lipid membranes, as previously suggested by molecular dynamics calculations.
Soft Condensed Matter (cond-mat.soft)
J. Photoch. Photobio. B 2024, 250, 112833
Dynamical pathways for the interaction of O2, H2O, CH4, and CO2 with a-alumina surfaces: Density functional tight-binding calculations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-19 20:00 EST
F. J. Dominguez-Gutierrez, Amil Aligayev, Wenyi Huo, Muralidhar Chourashiya, Qinqin Xu, Stefanos Papanikolaou
In this study, we investigated the physisorption mechanisms of O2, H2O, CH4, and CO2 molecules on alumina and their effect on electronic properties. We employed quantum-classical molecular dynamics simulations and the self-consistent-charge density-functional tight-binding (SCC-DFTB) approach to dynamically model these mechanisms. Our results revealed the binding pathways of O, H, and C atoms in the various molecules to Al and O atoms at the top atomic layers of the alpha-alumina surface. We examined several adsorption sites and molecular orientations relative to Al-terminated and Ox-terminated alumina surfaces and found that the most stable physisorbed state on the Al-terminated surface is located above the Al atom, while the Ox-terminated state is found above the oxygen, resulting in enhanced optical adsorbance. The dissociation of CH4 into CH2+H2 after interaction with the surface resulted in hydrogen production, but with low adsorbate rates. While, O2 molecules primarily bond to the Al atoms, leading to the highest adsorbance rate among the other molecules. Our findings provide important insights into the physisorption mechanisms of molecules on alumina and their impact on electronic properties
Materials Science (cond-mat.mtrl-sci)
Hydrodynamic stability and pattern formation in hexatic epithelial layers
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-19 20:00 EST
Josep-Maria Armengol-Collado, Leonardo Puggioni, Livio N. Carenza, Luca Giomi
We investigate the hydrodynamic stability and the formation of patterns in a continuum model of epithelial layers, able to account for the interplay between mechanical activity, lateral adhesion and the \(6-\)fold orientational order originating from the hexagonal morphology of the cells. Unlike in other models of active liquid crystals, the balance between energy injection and dissipation can here involve multiple length scales, resulting in a large spectrum of dynamical behaviors. When kinetic energy is dissipated by the cells' adhesive interactions at a rate higher that at which is injected by active stresses, the quiescent state of the cellular layer is generically stable: i.e. hydrodynamically stable regardless of its size. On the other hand, as the cellular layer becomes progressively more active, this homeostatic condition is altered by a hierarchy of pattern-forming instabilities, where the system organizes in an increasingly large number of counter-flowing lanes of fixed width. In two-dimensional periodic domains, the latter organization is itself unstable to the proliferation of vortices and the dynamics of the cellular layer becomes eventually chaotic and yet different from the more common active turbulence.
Soft Condensed Matter (cond-mat.soft)
11 pages, 8 figures
Statistical Uncertainties of Limit Cycle Systems in Langevin Bath
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-02-19 20:00 EST
Dipesh K. Singh, P. K. Mohanty
We show that limit cycle systems in Langevin bath exhibit uncertainty in observables that define the limit-cycle plane, and maintain a positive lower bound. The uncertainty-bound depends on the parameters that determine the shape and periodicity of the limit cycle. In one dimension, we use the framework of canonical dissipative systems to construct the limit cycle, whereas in two dimensions, particle in central potentials with radial-dissipation provide us natural examples. We show that, the position-momenta uncertainty of particle in a central potential is larger than half the magnitude of the angular momentum (conserved) of the particle. We also investigate how uncertainties, which are absent in deterministic systems, increase with time when the systems are attached to a bath and eventually cross the lower bound before reaching the steady state.
Statistical Mechanics (cond-mat.stat-mech)
8 pages + 6 figures + supplemental material