CMP Journal 2025-07-31
Statistics
Nature Materials: 3
Nature Nanotechnology: 2
Science: 16
Physical Review Letters: 17
Physical Review X: 2
arXiv: 87
Nature Materials
Flatland wakes based on leaky hyperbolic polaritons
Original Paper | Nanophotonics and plasmonics | 2025-07-30 20:00 EDT
Na Chen, Hanchao Teng, Hai Hu, Min Liu, Chengyu Jiang, Zhuoxin Xue, Hualong Zhu, Jiayi Gui, Peining Li, Andrea Alù, Qing Dai
Hyperbolic polaritons facilitate nanoscale light manipulation, but strong field confinement limits their transmission across interfaces. Conversely, leaky waves can convert radiation from confined sources towards the far field. Here we combine hyperbolic polaritons and leaky wave radiation to demonstrate flatland leaky polaritonic wakes. We employ a mixed-dimensional van der Waals heterostructure consisting of a nanoscale waveguide strip on a van der Waals film. The waveguide mode, confined inside the hyperbolic light cone of the background film, enables efficient directional in-plane emission of fast phonon polaritons. The constructive interference of these leaky polaritons generates highly directional polaritonic wakes. Their spatial symmetry can be tailored through the orientation of the heterostructure with respect to the hyperbolic film dispersion. Leveraging van der Waals stacking, we also demonstrate effective acceleration and deceleration of polaritonic wakes by locally tailoring the leaky nano-waveguide dispersion through gradient thickness design. Our findings demonstrate that polaritonic wakes hold promise for integrated nanophotonic circuits.
Nanophotonics and plasmonics, Optical materials and structures
Bond-centric modular design of protein assemblies
Original Paper | Biomaterials - proteins | 2025-07-30 20:00 EDT
Shunzhi Wang, Andrew Favor, Ryan D. Kibler, Joshua M. Lubner, Andrew J. Borst, Nicolas Coudray, Rachel L. Redler, Huat Thart Chiang, William Sheffler, Yang Hsia, Neville P. Bethel, Zhe Li, Damian C. Ekiert, Gira Bhabha, Lilo D. Pozzo, David Baker
Directional interactions that generate regular coordination geometries are a powerful means of guiding molecular and colloidal self-assembly, but implementing such high-level interactions with proteins remains challenging due to their complex shapes and intricate interface properties. Here we describe a modular approach to protein nanomaterial design inspired by the rich chemical diversity that can be generated from the small number of atomic valencies. We design protein building blocks using deep learning-based generative tools, incorporating regular coordination geometries and tailorable bonding interactions that enable the assembly of diverse closed and open architectures guided by simple geometric principles. Experimental characterization confirms the successful formation of more than 20 multicomponent polyhedral protein cages, two-dimensional arrays and three-dimensional protein lattices, with a high (10%-50%) success rate and electron microscopy data closely matching the corresponding design models. Due to modularity, individual building blocks can assemble with different partners to generate distinct regular assemblies, resulting in an economy of parts and enabling the construction of reconfigurable networks for designer nanomaterials.
Biomaterials - proteins, Protein design
Computational design of bifaceted protein nanomaterials
Original Paper | Electron microscopy | 2025-07-30 20:00 EDT
Sanela Rankovic, Kenneth D. Carr, Justin Decarreau, Rebecca Skotheim, Ryan D. Kibler, Sebastian Ols, Sangmin Lee, Jung-Ho Chun, Marti R. Tooley, Justas Dauparas, Helen E. Eisenach, Matthias Glögl, Connor Weidle, Andrew J. Borst, David Baker, Neil P. King
Advances in computational methods have led to considerable progress in the design of protein nanomaterials. However, nearly all nanoparticles designed so far exhibit strict point group symmetry, which limits structural diversity and precludes anisotropic functionalization. Here we describe a computational strategy for designing multicomponent bifaceted protein nanomaterials with two distinctly addressable sides. The method centres on docking pseudosymmetric hetero-oligomeric building blocks in architectures with dihedral symmetry and designing an asymmetric protein-protein interface between them. We obtain an initial 30-subunit assembly with pseudo-D5 symmetry and generate variants in which we alter the size and morphology of the bifaceted nanoparticles by designing extensions to one of the subunits. Functionalization of the two nanoparticle faces with protein minibinders enables the specific colocalization of two populations of polystyrene microparticles coated with the target protein receptors. The ability to accurately design anisotropic protein nanoparticles could be broadly useful in applications requiring the colocalization of distinct target moieties.
Electron microscopy, Nanoparticles, Nanostructures, Protein design, Proteins
Nature Nanotechnology
Ultrawide-bandwidth boron nitride photonic memristors
Original Paper | Electronic devices | 2025-07-30 20:00 EDT
Maolin Chen, Yinchang Ma, Nabeel Aslam, Chen Liu, Yiqiang Chen, Linqu Luo, Xiaowen Zhang, Kairan Mai, Han Xiao, Kaichen Zhu, Osamah Alharbi, Dongxing Zheng, Xiangming Xu, Hanguang Liao, Yiming Yang, Heng Wang, Zhican Zhou, Hanwen Wang, Bo Tian, Junzhu Li, Xin He, Kai Chang, Yating Wan, Atif Shamim, Husam N. Alshareef, Mario Lanza, Thomas D. Anthopoulos, Zheng Han, Fei Xue, Xixiang Zhang
Photonic memristors based on two-dimensional materials are emerging as critical components for ultrascalable, energy-efficient artificial vision systems, integrating opto-sensing, data storage and processing capabilities. However, existing devices typically exhibit narrow spectral response ranges and operate in a single mode (for example, non-volatility), limiting their applications in complex computing scenarios. Here we introduce photonic memristor arrays based on a wafer-scale hexagonal boron nitride (hBN)/silicon (Si) heterostructure. These memristors are developed via in situ, low-temperature (250 °C), large-area growth of highly homogeneous hBN films on Si-based substrates. The devices exhibit opto-reconfigurability across a broad spectral range from ultraviolet to near infrared. By adjusting the incident laser power, the device can be reconfigured between non-resistive-switching, volatile and non-volatile modes. This light-induced reconfigurability is attributed to the formation of conductive filaments through interactions between hydrogen ions and photogenerated electrons within the engineered hBN/Si heterostructures. Furthermore, the photonic memristor features a switching ratio exceeding 109, retention time surpassing 40,000 s, endurance over 106 cycles and thermal stability up to 300 °C. These findings provide a scalable solution for developing integrated sensing-storage-computation artificial vision systems, fully compatible with sophisticated Si-based semiconductor technologies.
Electronic devices, Information storage
On-chip direct synthesis of boron nitride memristors
Original Paper | Electronic devices | 2025-07-30 20:00 EDT
Jing Xie, Ali Ebadi Yekta, Fahad Al Mamun, Kaichen Zhu, Maolin Chen, Sebastian Pazos, Wenwen Zheng, Xixiang Zhang, Seth Ariel Tongay, Xinyi Li, Huaqiang Wu, Robert Nemanich, Deji Akinwande, Mario Lanza, Ivan Sanchez Esqueda
Two-dimensional materials hold promise for advanced complementary metal-oxide-semiconductor (CMOS) and beyond-CMOS electronics, including neuromorphic and in-memory computing. Hexagonal boron nitride (hBN) is particularly attractive for non-volatile resistive-switching devices (that is, memristors) due to its outstanding electronic, mechanical and chemical stability. However, integrating hBN memristors with Si-CMOS electronics faces challenges as it requires either high-temperature synthesis (exceeding thermal budgets) or transfer methods that introduce defects, impacting device performance and reliability. Here we introduce the synthesis of hBN films at CMOS-compatible temperatures (<380 °C) using electron cyclotron resonance plasma-enhanced chemical vapour deposition to realize transfer-free, CMOS-compatible hBN memristors with outstanding electrical characteristics. Our studies indicate a polycrystalline structure with turbostratic features in as-deposited hBN films and good wafer-level uniformity in morphology (size, shape and orientation). We demonstrate a large array of hBN memristors achieving high yield (~90%), stability (endurance, retention and repeatability), programming precision for multistate operation (>16 states) and low-frequency noise performance with minimal random telegraph noise. Furthermore, we directly integrate memristive devices on industrial CMOS test vehicles to demonstrate excellent endurance, achieving millions of programming cycles with a high technology readiness level. This represents an important step towards the wafer-scale CMOS integration of hBN-memristor-based electronics.
Electronic devices
Science
Altered translation elongation contributes to key hallmarks of aging in the killifish brain
Research Article | Aging | 2025-07-31 03:00 EDT
Domenico Di Fraia, Antonio Marino, Jae Ho Lee, Erika Kelmer Sacramento, Mario Baumgart, Sara Bagnoli, Till Balla, Felix Schalk, Stephan Kamrad, Rui Guan, Cinzia Caterino, Chiara Giannuzzi, Pedro Tomaz da Silva, Amit Kumar Sahu, Hanna Gut, Giacomo Siano, Max Tiessen, Eva Terzibasi-Tozzini, Eugenio F. Fornasiero, Julien Gagneur, Christoph Englert, Kiran R. Patil, Clara Correia-Melo, Danny D. Nedialkova, Judith Frydman, Alessandro Cellerino, Alessandro Ori
Aging is a major risk factor for neurodegeneration and is characterized by diverse cellular and molecular hallmarks. To understand the origin of these hallmarks, we studied the effects of aging on the transcriptome, translatome, and proteome in the brain of short-lived killifish. We identified a cascade of events in which aberrant translation pausing led to altered abundance of proteins independently of transcriptional regulation. In particular, aging caused increased ribosome stalling and widespread depletion of proteins enriched in basic amino acids. These findings uncover a potential vulnerable point in the aging brain’s biology–the biogenesis of basic DNA and RNA binding proteins. This vulnerability may represent a unifying principle that connects various aging hallmarks, encompassing genome integrity, proteostasis, and the biosynthesis of macromolecules.
High-field superconducting halo in UTe2
Research Article | Superconductivity | 2025-07-31 03:00 EDT
Sylvia K. Lewin, Peter Czajka, Corey E. Frank, Gicela Saucedo Salas, G. Timothy Noe II, Hyeok Yoon, Yun Suk Eo, Johnpierre Paglione, Andriy H. Nevidomskyy, John Singleton, Nicholas P. Butch
The heavy fermion material UTe2 is a candidate topological superconductor that exhibits multiple magnetic field-induced superconducting phases. One such phase exists only at fields greater than 40 tesla, a considerable scale given its critical temperature of only 2 K. Here, we extend measurements of this state with fields outside of the bc crystallographic plane and reveal its core structure: The superconducting phase wraps around the b axis in a halo-like fashion and appears to be stabilized by a field component perpendicular to the magnetic easy axis. This angle dependence points to a multicomponent spin-triplet order parameter with a finite angular momentum of the Cooper pairs. The pairing mechanism remains enigmatic, and UTe2‘s specific magnetophilic superconducting tendencies seem incompatible with existing models for field-enhanced superconductivity.
Behavior drives morphological change during human evolution
Research Article | Paleoanthropology | 2025-07-31 03:00 EDT
Luke D. Fannin, Chalachew M. Seyoum, Vivek V. Venkataraman, Justin D. Yeakel, Christine M. Janis, Thure E. Cerling, Nathaniel J. Dominy
Dietary shifts and corresponding morphological changes can sometimes evolve in succession, not concurrently–an evolutionary process called behavioral drive. Detecting behavioral drive in the fossil record is challenging because it is difficult to measure behaviors independently from corresponding morphologies. To solve this problem, we focused on a puzzling behavior in the fossil record of some primates: eating graminoid plants. We report carbon and oxygen isotope ratios from fossil cercopithecid monkeys and integrate the data into a view of hominin dietary evolution, finding that changes in graminivorous behavior preceded corresponding changes in dental morphology by ~700,000 years. Decoupling diets and morphologies in time was conducive to determining when and to exploring why dietary changes helped to propel human evolution.
Genomic convergence in hibernating mammals elucidates the genetics of metabolic regulation in the hypothalamus
Research Article | Genetics | 2025-07-31 03:00 EDT
Elliott Ferris, Josue D. Gonzalez Murcia, Adriana Cristina Rodriguez, Susan Steinwand, Cornelia Stacher Hörndli, Dimitri Traenkner, Pablo J. Maldonado-Catala, Christopher Gregg
Extreme metabolic adaptations can elucidate genetic programs that govern mammalian metabolism. Here, we used convergent evolutionary changes in hibernating lineages to define conserved cis-regulatory elements (CREs) and metabolic programs. We characterized mouse hypothalamus gene expression and chromatin dynamics across fed, fasted, and refed states and then used comparative genomics of hibernating versus nonhibernating lineages to identify cis elements with convergent changes in hibernators. Multi-omics approaches pinpointed CREs, hub genes, regulatory programs, and cell types underlying lineage divergence. Hibernators accumulated loss-of-function effects for CREs regulating hypothalamic responses, and the refeeding period after fasting served as a key phase for molecular processes with convergent evolutionary changes. This work provides a genetic framework for harnessing hibernator adaptations to understand human metabolic control.
Conserved noncoding cis elements associated with hibernation modulate metabolic and behavioral adaptations in mice
Research Article | Genetics | 2025-07-31 03:00 EDT
Susan Steinwand, Cornelia Stacher Hörndli, Elliott Ferris, Jared Emery, Josue D. Gonzalez Murcia, Adriana Cristina Rodriguez, Riley J. Spotswood, Amandine Chaix, Alun Thomas, Crystal Davey, Christopher Gregg
Cis-regulatory elements (CREs) drive phenotypic diversity, yet how CREs are causally linked to function remains largely unclear. Our study elucidates functions for conserved cis elements associated with the evolution of mammalian hibernation and metabolic flexibility. Genomic analyses revealed topologically associated domains (TADs) enriched for convergent changes in hibernators, including the Fat Mass & Obesity (Fto) locus. In this TAD, we uncovered genetic circuits for metabolic responses and hibernation-linked cis elements forming regulatory contacts with neighboring genes. Deletions of individual cis elements in mice differentially altered Fto, Irx3, and Irx5 expression, reshaping downstream gene expression programs and affecting metabolism, torpor, obesogenesis, and foraging in distinct ways. Our findings show how convergent evolution in hibernators pinpoints functional genetic mechanisms of metabolic control, with multiple effects encoded in single CREs.
Pantropical tree rings show small effects of drought on stem growth
Research Article | Dendrochronology | 2025-07-31 03:00 EDT
Pieter A. Zuidema, Peter Groenendijk, Mizanur Rahman, Valerie Trouet, Abrham Abiyu, Rodolfo Acuña-Soto, Eduardo Adenesky-Filho, Raquel Alfaro-Sánchez, Claudio Roberto Anholetto, José Roberto Vieira Aragão, Gabriel Assis-Pereira, Claudia C. Astudillo-Sánchez, Ana Carolina Barbosa, Giovanna Battipaglia, Hans Beeckman, Paulo Cesar Botosso, Nils Bourland, Achim Bräuning, Roel Brienen, Matthew Brookhouse, Supaporn Buajan, Brendan M. Buckley, J. Julio Camarero, Artemio Carrillo-Parra, Gregório Ceccantini, Librado R. Centeno-Erguera, Julián Cerano-Paredes, Rosalinda Cervantes-Martínez, Wirong Chanthorn, Ya-Jun Chen, Bruno Barçante Ladvocat Cintra, Eladio Heriberto Cornejo-Oviedo, Otoniel Cortés-Cortés, Clayane Matos Costa, Camille Couralet, Doris Bianca Crispín-De-La-Cruz, Rosanne D’arrigo, Diego A. David, Maaike De Ridder, Jorge Ignacio Del Valle, Mário Dobner, Jean-Louis Doucet, Oliver Dünisch, Brian J. Enquist, Karin Esemann-Quadros, Gerardo Esquivel-Arriaga, Ze-Xin Fan, Adeline Fayolle, Tatiele Anete Bergamo Fenilli, M. Eugenia Ferrero, Esther Fichtler, Patrick M. Finnegan, Claudia Fontana, Kainana S. Francisco, Pei-Li Fu, Franklin Galvão, Aster Gebrekirstos, Jorge A. Giraldo, Emanuel Gloor, Milena Godoy-Veiga, Daniela Granato-Souza, Anthony Guerra, Kristof Haneca, Grant Logan Harley, Ingo Heinrich, Gerhard Helle, Bruna Hornink, Wannes Hubau, Janet G. Inga, Mahmuda Islam, Yu-Mei Jiang, Mark Kaib, Zakia Hassan Khamisi, Marcin Koprowski, Eva Layme, A. Joshua Leffler, Gauthier Ligot, Claudio Sergio Lisi, Neil J. Loader, Francisco De Almeida Lobo, Giuliano Maselli Locosselli, Tomaz Longhi-Santos, Lidio Lopez, María I. López-Hernández, José Luís Penetra Cerveira Lousada, Rubén D. Manzanedo, Amanda K. Marcon, Justin T. Maxwell, Omar N. Mendoza-Villa, Ítallo Romany Nunes Menezes, Mulugeta Mokria, Valdinez Ribeiro Montóia, Eddy Moors, Miyer Moreno, Miguel Angel Muñiz-Castro, Cristina Nabais, Anuttara Nathalang, Justine Ngoma, Francisco De Carvalho Nogueira, Juliano Morales Oliveira, Gabriela Morais Olmedo, Daigard Ricardo Ortega-Rodriguez, Carmen Eugenia Rodríguez Ortíz, Mariana Alves Pagotto, Shankar Panthi, Kathelyn Paredes-Villanueva, Gonzalo Pérez-de-Lis, Laura Patricia Ponce Calderón, Leif Armando Portal-Cahuana, Darwin Alexander Pucha-Cofrep, Nathsuda Pumijumnong, Paulo Quadri, Jorge Andrés Ramírez, Edilson Jimmy Requena-Rojas, Judith Reyes-Flores, Adauto de Souza Ribeiro, Iain Robertson, Fidel Alejandro Roig, José Guilherme Roquette, Ernesto Alonso Rubio-Camacho, Raúl Sánchez-Salguero, Ute Sass-Klaassen, Jochen Schöngart, Marcelo Callegari Scipioni, Paul R. Sheppard, Lucas C.R. Silva, Franziska Slotta, Leroy Soria-Díaz, Luciana K.V.S. Sousa, James H. Speer, Matthew D. Therrell, Ginette Ticse-Otarola, Mario Tomazello-Filho, Max C.A. Torbenson, Pantana Tor-Ngern, Ramzi Touchan, Jan Van den Bulcke, Lorenzo Vázquez-Selem, Adín H. Velázquez-Pérez, Alejandro Venegas-González, Ricardo Villalba, Jose Villanueva-Diaz, Mart Vlam, George Vourlitis, Christian Wehenkel, Tommy Wils, Erika S. Zavaleta, Eshetu Asfaw Zewdu, Yong-Jiang Zhang, Zhe-Kun Zhou, Flurin Babst
Increasing drought pressure under anthropogenic climate change may jeopardize the potential of tropical forests to capture carbon in woody biomass and act as a long-term carbon dioxide sink. To evaluate this risk, we assessed drought impacts in 483 tree-ring chronologies from across the tropics and found an overall modest stem growth decline (2.5% with a 95% confidence interval of 2.2 to 2.7%) during the 10% driest years since 1930. Stem growth declines exceeded 10% in 25% of cases and were larger at hotter and drier sites and for gymnosperms compared with angiosperms. Growth declines generally did not outlast drought years and were partially mitigated by growth stimulation in wet years. Thus, pantropical forest carbon sequestration through stem growth has hitherto shown drought resilience that may, however, diminish under future climate change.
Silencing mitochondrial gene expression in living cells
Research Article | Cell biology | 2025-07-31 03:00 EDT
Luis Daniel Cruz-Zaragoza, Drishan Dahal, Mats Koschel, Angela Boshnakovska, Aiturgan Zheenbekova, Mehmet Yilmaz, Marcel Morgenstern, Jan-Niklas Dohrke, Julian Bender, Anusha Valpadashi, Kristine A. Henningfeld, Silke Oeljeklaus, Laura Sophie Kremer, Mirjam Breuer, Oliver Urbach, Sven Dennerlein, Michael Lidschreiber, Stefan Jakobs, Bettina Warscheid, Peter Rehling
Mitochondria fulfill central functions in metabolism and energy supply. They express their own genome, which encodes key subunits of the oxidative phosphorylation system. However, the central mechanisms underlying mitochondrial gene expression remain enigmatic, and a lack of suitable technologies to target mitochondrial protein synthesis in cells has limited experimental access. We silenced the translation of specific mitochondrial mRNAs in living human cells by delivering synthetic peptide-morpholino chimeras. This approach allowed us to perform a comprehensive temporal monitoring of cellular responses. Our study provides insights into mitochondrial translation, its integration into cellular physiology, and provides a strategy to address mitochondrial gene expression in living cells. The approach can potentially be used to analyze mechanisms and pathophysiology of mitochondrial gene expression in a range of cellular model systems.
Vaccination with mRNA-encoded nanoparticles drives early maturation of HIV bnAb precursors in humans
Research Article | Clinical trials | 2025-07-31 03:00 EDT
Jordan R. Willis, Madhu Prabhakaran, Michelle Muthui, Ansuya Naidoo, Troy Sincomb, Weiwei Wu, Christopher A. Cottrell, Elise Landais, Allan C. deCamp, Nahid R. Keshavarzi, Oleksandr Kalyuzhniy, Jeong Hyun Lee, Linda M. Murungi, Wilfrida A. Ogonda, Nicole L. Yates, Martin M. Corcoran, Swastik Phulera, Joel Musando, Amanda Tsai, Gabrielle Lemire, Yiakon Sein, Michael Muteti, Praveen Alamuri, Jennifer A. Bohl, Drienna Holman, Sunny Himansu, Brett Leav, Caroline Reuter, Li-An Lin, Baoyu Ding, Chunla He, Walter L. Straus, Kellie J. MacPhee, Isabel Regadas, Diana V. Nyabundi, Ruth Chirchir, Omu Anzala, John N. Kimotho, Caleb Kibet, Kelli Greene, Hongmei Gao, Erica Beatman, Kiara Benson, Dominick Laddy, David M. Brown, Rhianna Bronson, Jalen Jean-Baptiste, Suprabhath Gajjala, Zahra Rikhtegaran-Tehrani, Alison Benner, Mukundhan Ramaswami, Danny Lu, Nushin Alavi, Sonya Amirzehni, Michael Kubitz, Ryan Tingle, Erik Georgeson, Nicole Phelps, Yumiko Adachi, Alessia Liguori, Claudia Flynn, Katherine McKenney, Xiaoya Zhou, D. Collins Owuor, Sharon A. Owuor, Soo-Young Kim, Michael Duff, Ju Yeong Kim, Grace Gibson, Sabyasachi Baboo, Jolene Diedrich, Torben Schiffner, Marisa Shields, Mabela Matsoso, Jennifer Santos, Kristen Syvertsen, Allison Kennedy, Melissa Schroeter, Johan Vekemans, John R. Yates, James C. Paulson, Ollivier Hyrien, Adrian B. McDermott, Pholo Maenetje, Julien Nyombayire, Etienne Karita, Rosine Ingabire, Vinodh Edward, Vincent Muturi-Kioi, Janine Maenza, Adrienne E. Shapiro, M. Juliana McElrath, Srilatha Edupuganti, Barbara S. Taylor, David Diemert, Gabriel Ozorowski, Richard A. Koup, David Montefiori, Andrew B. Ward, Gunilla B. Karlsson Hedestam, Georgia Tomaras, Devin J. Hunt, Daniel Muema, Devin Sok, Dagna S. Laufer, Sarah F. Andrews, Eunice W. Nduati, William R. Schief
A leading HIV vaccine strategy requires a priming immunogen to induce broadly neutralizing antibody (bnAb) precursors, followed by a series of heterologous boosters to elicit somatic hypermutation (SHM) and produce bnAbs. In two randomized, open-label phase 1 human clinical trials, IAVI G002 in the United States and IAVI G003 in Rwanda and South Africa (IAVI, International Aids Vaccine Initiative), we evaluated the safety and immunogenicity of mRNA-encoded nanoparticles as priming immunogens (both trials) and first-boosting immunogens (IAVI G002). The vaccines were generally safe and well tolerated, except that 18% of IAVI G002 participants experienced skin reactions. Priming induced bnAb precursors with substantial frequencies and SHM; heterologous boosting elicited increased SHM, affinity, and neutralization activity toward bnAb development; and elicited antibodies exhibited precise bnAb structural mimicry. The results establish clinical proof of concept that heterologous boosting can advance bnAb precursor maturation and demonstrate bnAb priming in Africa, where the HIV burden is highest.
Dust-driven droplet freezing explains cloud-top phase in the northern extratropics
Research Article | Clouds | 2025-07-31 03:00 EDT
D. Villanueva, M. Stengel, C. Hoose, O. Bruno, K. Jeggle, A. Ansmann, U. Lohmann
Clouds between -39° and 0°C can be topped by a liquid or ice layer, which affects their radiative forcing and precipitation. The cloud-top ice-to-total frequency (ITF) quantifies the occurrence of clouds with an ice top relative to total cloud occurrence, but the factors controlling ITF are poorly understood. Using 35 years of satellite data, we show that in the Northern Hemisphere, between -15° and -30°C, dust aerosol is strongly correlated with ITF in both time and space. Furthermore, we found that the sensitivities of ITF to temperature and dust are in a ratio that agrees with laboratory measurements of droplet freezing, showing that ITF can be attributed to dust aerosol.
Acoustic wave modulation of gap plasmon cavities
Research Article | Plasmonics | 2025-07-31 03:00 EDT
Skyler P. Selvin, Majid Esfandyarpour, Anqi Ji, Yan Joe Lee, Colin Yule, Jung-Hwan Song, Mohammad Taghinejad, Mark L. Brongersma
The important role of metallic nanostructures in nanophotonics will expand if ways to electrically manipulate their optical resonances at high speed can be identified. We capitalized on electrically driven surface acoustic waves and the extreme light concentration afforded by gap plasmons to achieve this goal. We placed gold nanoparticles in a particle-on-mirror configuration with a few-nanometer-thick, compressible polymer spacer. Surface acoustic waves were then used to tune light scattering at speeds approaching the gigahertz regime. We observed evidence that the surface acoustic waves produced mechanical deformations in the polymer and that ensuing nonlinear mechanical dynamics led to unexpectedly large levels of strain and spectral tuning. Our approach provides a design strategy for electrically driven dynamic metasurfaces and fundamental explorations of high-frequency, polymer dynamics in ultraconfined geometries.
Precise targeting of HIV broadly neutralizing antibody precursors in humans
Research Article | Clinical trials | 2025-07-31 03:00 EDT
Tom G. Caniels, Madhu Prabhakaran, Gabriel Ozorowski, Kellie J. MacPhee, Weiwei Wu, Karlijn van der Straten, Sashank Agrawal, Ronald Derking, Emma I. M. M. Reiss, Katrina Millard, Martina Turroja, Aimee Desrosiers, Jeffrey Bethony, Elissa Malkin, Marinus H. Liesdek, Annelou van der Veen, Michelle Klouwens, Jonne L. Snitselaar, Joey H. Bouhuijs, Rhianna Bronson, Jalen Jean-Baptiste, Suprabhath Gajjala, Zahra Rikhtegaran Tehrani, Alison Benner, Mukundhan Ramaswami, Michael O. Duff, Yung-Wen Liu, Alicia H. Sato, Ju Yeong Kim, Isabel J. L. Baken, Catarina Mendes Silva, Tom P. L. Bijl, Jacqueline van Rijswijk, Judith A. Burger, Albert Cupo, Anila Yasmeen, Swastik Phulera, Wen-Hsin Lee, Kipchoge N. Randall, Shiyu Zhang, Martin M. Corcoran, Isabel Regadas, Alex C. Sullivan, David M. Brown, Jennifer A. Bohl, Kelli M. Greene, Hongmei Gao, Nicole L. Yates, Sheetal Sawant, Jan M. Prins, Neeltje A. Kootstra, Stephen M. Kaminsky, Burc Barin, Farhad Rahaman, Margaret Meller, Vince Philiponis, Dagna S. Laufer, Angela Lombardo, Lindsey Mwoga, Solmaz Shotorbani, Drienna Holman, Richard A. Koup, Per Johan Klasse, Gunilla B. Karlsson Hedestam, Georgia D. Tomaras, Marit J. van Gils, David C. Montefiori, Adrian B. McDermott, Ollivier Hyrien, John P. Moore, Ian A. Wilson, Andrew B. Ward, David J. Diemert, Godelieve J. de Bree, Sarah F. Andrews, Marina Caskey, Rogier W. Sanders
A protective HIV vaccine will need to induce broadly neutralizing antibodies (bnAbs) in humans, but priming rare bnAb precursor B cells has been challenging. In a double-blinded, placebo-controlled phase 1 human clinical trial, the recombinant, germline-targeting envelope glycoprotein (Env) trimer BG505 SOSIP.v4.1-GT1.1, adjuvanted with AS01B, induced bnAb precursors of the VRC01-class at a high frequency in the majority of vaccine recipients. These bnAb precursors, which target the CD4 receptor binding site, had undergone somatic hypermutation characteristic of the VRC01-class. A subset of isolated VRC01-class monoclonal antibodies neutralized wild-type pseudoviruses and was structurally extremely similar to bnAb VRC01. These results further support germline-targeting approaches for human HIV vaccine design and demonstrate atomic-level manipulation of B cell responses with rational vaccine design.
Comparative connectomics of two distantly related nematode species reveals patterns of nervous system evolution
Research Article | Neuroscience | 2025-07-31 03:00 EDT
Steven J. Cook, Cristine A. Kalinski, Curtis M. Loer, Nadin Memar, Maryam Majeed, Sarah Rebecca Stephen, Daniel J. Bumbarger, Metta Riebesell, Barbara Conradt, Ralf Schnabel, Ralf J. Sommer, Oliver Hobert
Understanding the evolution of the bilaterian brain requires a detailed exploration of the precise nature of cellular and subcellular differences between related species. We undertook an electron micrographic reconstruction of the brain of the predatory nematode Pristionchus pacificus and compared the results with the brain of Caenorhabditis elegans, which diverged at least 100 million years ago. We revealed changes in neuronal cell death, neuronal cell position, axodendritic projection patterns, and synaptic connectivity of homologous neurons that display no obvious changes in overall neurite morphology and projection patterns. These multiscale patterns of evolutionary changes show no bias to specific brain regions or neuron types.
Diversity-oriented photobiocatalytic synthesis via stereoselective three-component radical coupling
Research Article | 2025-07-31 03:00 EDT
Chen Zhang, Jun Zhou, Pei-Pei Xie, Silvia M. Rivera, Turki M. Alturaifi, James Finnigan, Simon Charnock, Peng Liu, Yang Yang
Enzymatic multicomponent C-C bond forming reactions for diversity-oriented synthesis remain rare. Using cooperative photobiocatalysis, we developed a stereoselective three-component radical-mediated C-C coupling unknown in both organic chemistry and biochemistry. Directed evolution of repurposed pyridoxal decarboxylases enabled full fragment variability in this three-component coupling, giving rise to six classes of valuable products, many of which were inaccessible by other methods, even in a racemic fashion. This enzymatic platform integrates a range of asymmetric catalysis principles, including remote stereocenter construction, stereodivergent catalysis, kinetic resolution and parallel kinetic resolution, achieving excellent diastereo- and enantiocontrol over radical intermediates. The broad substrate scope and complementary specificities of evolved enzyme variants enabled combinatorial library synthesis, affording structurally and stereochemically diverse scaffolds for medicinal chemistry.
A molecular machine directs the synthesis of a catenane
Research Article | Molecular machines | 2025-07-31 03:00 EDT
Tommy Wachsmuth, Robert Kluifhooft, Mira Müller, Leon Zeiß, Michael Kathan
Precise mechanical manipulation of molecules is inherently difficult owing to random thermal motion. Although directed movement on the molecular scale has been achieved, using it to impose specific–especially energetically disfavored–shapes on molecules and construct mechanically interlocked structures remains a fundamental challenge. In this study, we report the synthesis of a catenane enabled by a molecular motor that winds molecular strands into discrete entangled structures, each defined by a specific number of mechanical crossings. Light energy drives unidirectional motor rotation, enabling path-dependent control over a sequence of thermodynamically disfavored yet mechanically distinct and kinetically stable winding states, which are covalently captured and subsequently released to yield a catenane. This machine-directed approach offers a general proof-of-concept strategy for the template-free construction of mechanically interlocked molecules.
Cryo-EM structure of endogenous Plasmodium falciparum Pfs230 and Pfs48/45 fertilization complex
Research Article | 2025-07-31 03:00 EDT
Melanie H. Dietrich, Jill Chmielewski, Li-Jin Chan, Li Lynn Tan, Amy Adair, Frankie M. T. Lyons, Mikha Gabriela, Sash Lopaticki, Toby A Dite, Laura F Dagley, Lucia Pazzagli, Priya Gupta, Mohd Kamil, Ashley M. Vaughan, Rattanaporn Rojrung, Anju Abraham, Ramin Mazhari, Rhea J. Longley, Kathleen Zeglinski, Quentin Gouil, Ivo Mueller, Stewart A. Fabb, Rekha Shandre-Mugan, Colin W. Pouton, Alisa Glukhova, Shabih Shakeel, Wai-Hong Tham
Malaria parasite fertilization occurs in the midgut of a female Anopheles mosquito. Blocking fertilization within the mosquito can prevent malaria transmission. Plasmodium falciparum Pfs230 and Pfs48/45 are critical for male fertility and transmission of the malaria parasite. They form a core fertilization complex, but it is unknown how they interact. We determined a cryo-electron microscopy structure of endogenous Pfs230-Pfs48/45 complex showing that Pfs48/45 interacts with Pfs230 domains 13 and 14. Transgenic parasite lines with these domains removed were defective in Pfs230 gamete localization and showed reduced oocyst formation. Nanobodies against domains 13 and 14 inhibited Pfs230-Pfs48/45 complex formation, reduced transmission and structural analyses revealed their epitopes. These Pfs230 domains were targets of naturally acquired immunity and immune sera from mRNA-lipid nanoparticle immunizations blocked parasite transmission.
Escherichia coli with a 57-codon genetic code
Research Article | 2025-07-31 03:00 EDT
Wesley E. Robertson, Fabian B. H. Rehm, Martin Spinck, Raffael L. Schumann, Rongzhen Tian, Wei Liu, Yangqi Gu, Askar A. Kleefeldt, Cicely F. Day, Kim C. Liu, Yonka Christova, Jérôme F. Zürcher, Franz L. Böge, Jakob Birnbaum, Linda van Bijsterveldt, Jason W. Chin
The near-universal genetic code uses 64 codons to encode the 20 canonical amino acids and protein synthesis. Here we designed and generated Escherichia coli with a 4 Mb synthetic genome in which we replaced known occurrences of six sense codons and a stop codon with synonymous codons. The resulting organism, Syn57, uses 55 codons to encode the 20 canonical amino acids.
Physical Review Letters
Unveiling a Hidden Percolation Transition in Monitored Clifford Circuits: Inroads from ZX Calculus
Research article | Entanglement entropy | 2025-07-30 06:00 EDT
Einat Buznach Ahituv, Jonathan Ruhman, and Debanjan Chowdhury
We revisit the measurement-induced phase transition (MPT) in Clifford circuits, which are both classically simulable and exhibit critical behavior widely believed to be distinct from classical percolation theory, using ZX calculus. We analyze the MPT in a dynamical model composed of controlled not (cnot) gates, SWAP gates, identity gates, and Bell-pair measurements, respectively, arranged randomly in a brickwork pattern. Our circuits exhibit a transition that is seemingly distinct from classical percolation based on standard arguments, that is in line with the prevailing understanding in the field. In contrast, by employing ZX-calculus based simplification techniques, we unveil a hidden percolation transition within the circuit structure. We demonstrate that the classical percolation transition in the ZX-simplified network coincides with the MPT observed through mutual information. Our findings suggest that the MPT in Clifford circuits is, in fact, controlled by a classical percolation transition in disguise.
Phys. Rev. Lett. 135, 050402 (2025)
Entanglement entropy, Percolation, Phase transitions, Quantum circuits, Quantum measurements
Realization of High-Fidelity Perfect Entanglers between Remote Superconducting Quantum Processors
Research article | Quantum circuits | 2025-07-30 06:00 EDT
Juan Song, Shuang Yang, Pei Liu, Hui-Li Zhang, Guang-Ming Xue, Zhen-Yu Mi, Wen-Gang Zhang, Fei Yan, Yi-Rong Jin, and Hai-Feng Yu
Superconducting qubit systems, one of the leading candidates for universal quantum computing, face scalability challenges such as frequency crowding, wiring complexity, and packaging problems. Distributed quantum computing offers a viable strategy for constructing larger quantum information processing systems. Yet, direct universal quantum gates between remote qubits—critical to distributed architectures—remain unrealized. Here, we demonstrate direct high-fidelity entangling gates between two remote superconducting quantum processors separated by a 30 cm distance, utilizing standing-wave modes in their connecting coaxial cable. We achieve cross-entropy benchmarking fidelities of $(99.15\pm{}0.02)%$ and $(98.03\pm{}0.04)%$ for the controlled-not and controlled-z gates, respectively, outperforming state transfer and feedback-based protocols in fidelity and efficiency. This advancement significantly enhances the prospect of universal distributed quantum information processing, which is the critical step toward future large-scale quantum systems.
Phys. Rev. Lett. 135, 050603 (2025)
Quantum circuits, Quantum computation, Quantum control, Quantum engineering, Quantum information processing
Deviations from the Porter-Thomas Distribution due to Nonstatistical $\gamma $ Decay below the $^{150}\mathrm{Nd}$ Neutron Separation Threshold
Research article | Electromagnetic transitions | 2025-07-30 06:00 EDT
O. Papst, J. Isaak, V. Werner, D. Savran, N. Pietralla, G. Battaglia, T. Beck, M. Beuschlein, S. W. Finch, U. Friman-Gayer, K. E. Ide, R. V. F. Janssens, M. D. Jones, J. Kleemann, B. Löher, M. Scheck, M. Spieker, W. Tornow, R. Zidarova, and A. Zilges
We introduce a new method for the study of fluctuations of partial transition widths based on nuclear resonance fluorescence experiments with quasimonochromatic linearly polarized photon beams below particle separation thresholds. It is based on the average branching of decays of $J=1$ states of an even-even nucleus to the ${2}_{1}^{+}$ state in comparison to the ground state. Between 5 and 7 MeV, a constant average branching ratio for $\gamma $ decays from ${1}^{- }$ states of 0.490(16) is observed for the nuclide $^{150}\mathrm{Nd}$. Assuming ${\chi }^{2}$-distributed partial transition widths, this average branching ratio is related to a degree of freedom of $\nu =1.93(12)$, rejecting the validity of the Porter-Thomas distribution, requiring $\nu =1$. The observed deviation can be explained by nonstatistical effects in the $\gamma $-decay behavior with contributions in the range of 9.4(10)% up to 94(10)%.
Phys. Rev. Lett. 135, 052501 (2025)
Electromagnetic transitions, Gamma-ray strength functions, Photonuclear reactions, 150 ≤ A ≤ 189, Lifetimes & widths, Nuclear data analysis & compilation, Random matrix theory, Spectrometers & spectroscopic techniques, Thermal & statistical models
Neutralization of Multiply Charged Ground-State Ions by Collective Electron Transfer from an Environment
Research article | Atomic & molecular clusters | 2025-07-30 06:00 EDT
Lutz Marder, Catmarna Küstner-Wetekam, Nils Kiefer, Johannes Viehmann, Niklas Golchert, Emilia Heikura, Florian Trinter, Denis Cubaynes, Jérôme Palaudoux, Francis Penent, Arno Ehresmann, Lorenz S. Cederbaum, Přemysl Kolorenč, and Andreas Hans
Highly charged cations are omnipresent species after the interaction of high-energy or high-intensity light with matter. When embedded in environments, the mechanism and outcome of the redistribution of the cation’s charge are crucial for the further fate of the whole system. Generally, ground-state cations can decay by charge transfer, proceeding radiatively, through nuclear dynamics, or by electron-transfer-mediated decay (ETMD). ETMD causes electron emission from a remote neighbor and appears ubiquitous in loosely bound systems. It remained unclear how multiply charged ions decay if conventional ETMD channels are closed. Here, we show that a yet undiscovered variant of ETMD is possible, where multiple electrons are collectively transferred. Explicitly, we observe ETMD in which two electrons from two distinct neighbors (partially) neutralize a multiply charged ion, and an electron from a fourth site is emitted. According to the established nomenclature, we suggest naming the process ETMD(4).
Phys. Rev. Lett. 135, 053201 (2025)
Atomic & molecular clusters, Chemical charge transfer, Collective effects in clusters, Clusters
Collective Nuclear Excitation and Pulse Propagation in Single-Mode X-Ray Waveguides
Research article | Collective effects in quantum optics | 2025-07-30 06:00 EDT
Leon M. Lohse, Petar Andrejić, Sven Velten, Malte Vassholz, Charlotte Neuhaus, Ankita Negi, Anjali Panchwanee, Ilya Sergeev, Adriana Pálffy, Tim Salditt, and Ralf Röhlsberger
Waveguides offer a means to controllably couple atomic ensembles to the electromagnetic field therein. Here, we demonstrate x-ray propagation in planar thin-film waveguides coupled to M"ossbauer nuclei under collective resonant excitation by short pulses of synchrotron radiation. We record x-ray photons that have been emitted into resonant modes of the waveguide. Depending on the geometry and mode of excitation, two fundamentally different signatures of the collective emission are observed, for which we present a unifying theoretical model. Our results form a new platform for waveguide quantum electrodynamics in the hard x-ray regime with the potential to provide a coherent narrow band source of x-rays on the nanometer scale.
Phys. Rev. Lett. 135, 053601 (2025)
Collective effects in quantum optics, Light-matter interaction, Nanophotonics, Nuclear & electron resonance, Spontaneous emission, Superradiance & subradiance, X-ray beams & optics, Atomic ensemble, Waveguides, Mössbauer spectroscopy, Photon counting, X-ray scattering
Transport Measurements of Majorization Order for Wave Coherence
Research article | Light propagation, transmission & absorption | 2025-07-30 06:00 EDT
Cheng Guo, David A. B. Miller, and Shanhui Fan
We investigate the majorization order for comparing wave coherence and reveal its fundamental consequences in transport measurements, including power distribution, absorption, transmission, and reflection. We prove that all these measurements preserve the majorization order under unitary control, enabling direct experimental characterization of the majorization order. Specifically, waves with lower coherence in the majorization order exhibit more restricted ranges of achievable measurement values. Our results deepen the understanding of coherence in transport phenomena.
Phys. Rev. Lett. 135, 053801 (2025)
Light propagation, transmission & absorption, Optical coherence, Quantum coherence & coherence measures, Transport phenomena, Wave scattering, Complex media, Density matrix methods, S-matrix method in transport
Polarization Inversion with Parity–Time-Reversal–Duality Symmetric Scatterers
Research article | Metasurfaces | 2025-07-30 06:00 EDT
Roee Geva, Mário G. Silveirinha, and Raphael Kastner
We demonstrate, both theoretically and experimentally, that arbitrary scatterers preserving parity–time-reversal–duality ($\mathcal{P}\cdot{}\mathcal{T}\cdot{}\mathcal{D}$) symmetry inherently produce a backscattered wave whose electric field is the mirror-symmetric counterpart of the incident electric field, up to an amplitude factor, with respect to the system’s characteristic mirror plane. Specifically, we establish that a general elliptically polarized wave, when reflected from such structures, exhibits a polarization state related to the polarization ellipse of the incident wave by a parity transformation. Notably, a circularly polarized wave reflects with spin angular momentum opposite to that of the incident field, in stark contrast to reflection from conventional conducting objects. These findings enable several applications such as reflective polarizers and spin-selective devices.
Phys. Rev. Lett. 135, 053802 (2025)
Metasurfaces, PT-symmetry, Polarization, Symmetries
Shape Asymmetry and Flexibility in Active Cross-Stream Migration in Nonuniform Shear
Research article | Biological fluid dynamics | 2025-07-30 06:00 EDT
Derek C. Gomes and Tapan C. Adhyapak
We show that activity and broken fore-aft shape symmetry enable microswimmers to cross streamlines in nonuniform shear, a key yet overlooked factor in active cross-stream migration. Using a model of flagellated microswimmers in microchannel flow, we find that hydrodynamic coupling and flagellar flexibility significantly impact migration. A simplified theory identifies key factors driving the underlying rich nonlinear dynamics. Our findings apply to dynamics and control of both living and artificial microswimmers, while the hydrodynamic framework extends to diverse shear flow scenarios.
Phys. Rev. Lett. 135, 054001 (2025)
Biological fluid dynamics, Channel flow, Living matter & active matter, Slender body theory, Stokesian dynamics, Bacteria, Flagella, Low Reynolds number swimmers, Microswimmers, Self-propelled particles
Magnetic Double Helix
Research article | Plasma stability | 2025-07-30 06:00 EDT
Yang Zhang and Paul M. Bellan
Magnetic flux ropes, fundamental magnetohydrodynamic structures, often form braided helical configurations with net axial current, as observed in astrophysical and laboratory plasmas. However, an equilibrium model for such structures has remained elusive. We present a first-principles derivation of the braided flux ropes equilibrium by capturing the force balance of current-carrying plasma strands. This equilibrium reproduces the observed structure of the double helix nebula and provides a powerful tool for studying magnetic self-organization, plasma confinement, and astrophysical dynamics.
Phys. Rev. Lett. 135, 055201 (2025)
Plasma stability, Astrophysical jets, Magnetized plasma, Solar plasma, Magnetohydrodynamic techniques
Spatially Resolved Dynamics of the Amplitude Schmid-Higgs Mode in Disordered Superconductors
Research article | Impurities in superconductors | 2025-07-30 06:00 EDT
P. A. Nosov, E. S. Andriyakhina, and I. S. Burmistrov
We investigate the spatially resolved dynamics of the collective amplitude Schmid-Higgs (SH) mode in disordered $s$-wave superconductors and fermionic superfluids. By analyzing the analytic structure of the zero-temperature SH susceptibility in the complex frequency plane, we find that, when the coherence length greatly exceeds the mean free path, (i) the SH response at fixed wave vectors exhibits late-time oscillations decaying as $1/{t}^{2}$ with frequency $2\mathrm{\Delta }$, where $\mathrm{\Delta }$ is the superconducting gap; (ii) subdiffusive oscillations with a dynamical exponent $z=4$ emerge at late times and large distances; and (iii) spatial oscillations at a fixed frequency decay exponentially, with a period that diverges as the frequency approaches $2\mathrm{\Delta }$ from above. When the coherence length is comparable to the mean free path, additional exponentially decaying oscillations at fixed wave vectors appear with a frequency above $2\mathrm{\Delta }$. Furthermore, we show that the SH mode induces an extra peak in the third-harmonic generation current at finite wave vectors. The frequency of this peak is shifted from the conventional resonance at $\mathrm{\Delta }$, thereby providing an unambiguous signature of order parameter amplitude dynamics.
Phys. Rev. Lett. 135, 056001 (2025)
Impurities in superconductors, Quasiparticles & collective excitations, Superconducting fluctuations, Superconductivity, Superfluids
Flux-Controlled Two-Site Kitaev Chain
Research article | Majorana bound states | 2025-07-30 06:00 EDT
Ivan Kulesh, Sebastiaan L. D. ten Haaf, Qingzhen Wang, Vincent P. M. Sietses, Yining Zhang, Sebastiaan R. Roelofs, Christian G. Prosko, Di Xiao, Candice Thomas, Michael J. Manfra, and Srijit Goswami
Tunable long-range superconducting coupling makes it possible to engineer Majorana bound states in Kitaev chains.
Phys. Rev. Lett. 135, 056301 (2025)
Majorana bound states, Superconductors, Topological phases of matter, Transport phenomena, Josephson junctions, Superconductivity, Kitaev model
Efficient First-Principles Framework for Overdamped Phonon Dynamics and Anharmonic Electron-Phonon Coupling in Superionic Materials
Research article | Anharmonic lattice dynamics | 2025-07-30 06:00 EDT
Yuxuan Wang, Marios Zacharias, Xiao Zhang, Nick Pant, Jacky Even, Pierre F. P. Poudeu, and Emmanouil Kioupakis
Relying on the anharmonic special displacement method, we introduce an ab initio quasistatic polymorphous framework to describe local disorder, anharmonicity, and electron-phonon coupling in superionic conductors. Using cubic ${\mathrm{Cu}}_{2}\mathrm{Se}$, we show that positional polymorphism yields the breakdown of the phonon quasiparticle picture, leading to extremely overdamped anharmonic vibrations while preserving transverse acoustic phonons, consistent with experiments. We also demonstrate highly broadened electronic spectral functions with band gap openings of 1.0 eV due to polymorphism, and that anharmonic electron-phonon coupling leads to a band gap narrowing with increasing temperature. Our approach, relying on generating a handful of configurations, opens the way for efficient calculations in superionic crystals to elucidate their compelling high figure of merit.
Phys. Rev. Lett. 135, 056402 (2025)
Anharmonic lattice dynamics, Electron-phonon coupling, Electronic structure, Thermoelectrics, Density functional theory, First-principles calculations
Impact of Tiny Fermi Pockets with Extremely High Mobility on the Hall Anomaly in the Kagome Metal ${\mathrm{CsV}}{3}{\mathrm{Sb}}{5}$
Research article | Charge density waves | 2025-07-30 06:00 EDT
S. Liu, M. Roppongi, M. Kimata, K. Ishihara, R. Grasset, M. Konczykowski, B. R. Ortiz, S. D. Wilson, K. Yoshimi, T. Shibauchi, and K. Hashimoto
The Hall anomaly in the AV₃Sb₅ family of kagome metals originates from high-mobility tiny Fermi pockets formed by Fermi surface reconstruction at the charge-density-wave transition, rather than anomalous Hall mechanisms.
Phys. Rev. Lett. 135, 056502 (2025)
Charge density waves, Transport phenomena, Kagome metal, Topological materials, Shubnikov-de Haas effect
Observation of Antihelical Edge States in Acoustic Metamaterials
Research article | Edge states | 2025-07-30 06:00 EDT
Tianzhi Xia, Qicheng Zhang, and Chunyin Qiu
As a hallmark of the quantum Hall effect, chiral edge modes (CEMs) counterpropagate along the two parallel edges of a ribbon structure. However, recent studies demonstrate counterintuitive anti-CEMs that copropagate along the parallel edges. Analogous to the established extension of the CEMs to helical edge modes (HEMs) in the quantum spin Hall effect, it is natural to extend the anti-CEMs to anti-HEMs, which comprise a pair of time-reversal-related anti-CEMs. In this Letter, we report the first observation of the anti-HEMs based on a bilayer model that features staggered positive and negative interlayer hoppings. Experimentally, we implement this antihelical model on an acoustic platform and provide compelling evidence for the anti-HEMs by selectively exciting different spin subspaces, along with identifying the energy-biased Dirac points in bulk spectra. Our findings may offer new insights into topological phases of matter and potentially pave the way for designing novel devices with unique edge transport properties.
Phys. Rev. Lett. 135, 056601 (2025)
Edge states, Mechanical & acoustical properties, Topological phases of matter
Terahertz-Induced Second-Harmonic Generation in Quantum Paraelectrics: Hot-Phonon Effect
Research article | Critical phenomena | 2025-07-30 06:00 EDT
F. Yang, X. J. Li, D. Talbayev, and L. Q. Chen
Recent THz-pump second-harmonic-generation (SHG) probe measurements of quantum paraelectrics observed a significant long-lived nonoscillatory SHG component following an ultrafast resonant excitation of the soft mode, which was interpreted as a signature of THz-induced transient ferroelectric order. We propose that the THz-induced modulation of the SHG signal can be attributed solely to the dynamic variation of the dielectric environment associated with the lattice background, which reflects the coherent response of soft mode under THz pumping. We develop a temperature-dependent dynamic model incorporating the hot-phonon effect to simulate the soft-mode behaviors under ultrafast THz excitation. Its application to paraelectric ${\mathrm{KTaO}}_{3}$ produces quantitatively most of the features exhibited in our time-resolved SHG measurements and those in existing literature, including a long-lived nonoscillatory SHG response, SHG oscillations at twice the soft-mode frequency, SHG dampings, and temperature and field-strength dependencies. We conclude that the observed THz-induced nonoscillatory SHG response in quantum paraelectrics is a consequence of the nonequilibrium hot-phonon effect, offering an alternative to its existing interpretation as a signature of transient ferroelectric order.
Phys. Rev. Lett. 135, 056901 (2025)
Critical phenomena, Ferroelectricity, Light-matter interaction, Optical second-harmonic generation
Adaptive Node Positioning in Biological Transport Networks
Research article | Cellular organization, physiology & dynamics | 2025-07-30 06:00 EDT
Albert Alonso, Lars Erik J. Skjegstad, and Julius B. Kirkegaard
Biological transport networks are highly optimized structures that ensure power-efficient distribution of fluids across various domains, including animal vasculature and plant venation. Theoretically, these networks can be described as space-embedded graphs, and rich structures that align well with observations emerge from optimizing their hydrodynamic energy dissipation. Studies on these models typically use regular grids and focus solely on edge width optimization. Here, we present a generalization of the hydrodynamic graph model that permits additional optimization of node positioning. We achieve this by defining sink regions, accounting for the energy dissipation of delivery within these areas, and optimizing by means of differentiable physics. In the context of leaf venation patterns, our method results in organic networks that adapt to irregularities of boundaries and node misalignment, as well as overall improved efficiency. We study the dependency of the emergent network structures on the capillary delivery conductivity and identify a transition in which the network collapses above a critical threshold. Our findings provide insights into the early formation of biological systems and the efficient construction of transport networks.
Phys. Rev. Lett. 135, 058401 (2025)
Cellular organization, physiology & dynamics, Fitness, Network flow optimization, Network formation & growth, Network phase transitions, Transport in networks, Biological networks, Plants, Scaling methods
Erratum: Landau-Zener-St"uckelberg-Majorana Interferometry of a Single Hole [Phys. Rev. Lett. 120, 207701 (2018)]
Correction | | 2025-07-30 06:00 EDT
Alex Bogan, Sergei Studenikin, Marek Korkusinski, Louis Gaudreau, Piotr Zawadzki, Andy S. Sachrajda, Lisa Tracy, John Reno, and Terry Hargett
Phys. Rev. Lett. 135, 059901 (2025)
Physical Review X
Speed-Accuracy Relations for Diffusion Models: Wisdom from Nonequilibrium Thermodynamics and Optimal Transport
Research article | Diffusion | 2025-07-30 06:00 EDT
Kotaro Ikeda, Tomoya Uda, Daisuke Okanohara, and Sosuke Ito
An analysis that draws on nonequilibrium thermodynamics shows that thermodynamic dissipation limits data quality in diffusion models and that optimal transport dynamics yields more accurate generation than typical empirical methods.
Phys. Rev. X 15, 031031 (2025)
Diffusion, Fluctuation theorems, Stochastic thermodynamics, Machine learning
Spin Dynamics of Triple-$\mathbf{Q}$ Magnetic Orderings in a Triangular Lattice: Implications for Multi-$\mathbf{Q}$ Orderings in General Two-Dimensional Lattices
Research article | Antiferromagnetism | 2025-07-30 06:00 EDT
Pyeongjae Park, Woonghee Cho, Chaebin Kim, Yeochan An, Kazuki Iida, Ryoichi Kajimoto, Sakib Matin, Shang-Shun Zhang, Cristian D. Batista, and Je-Geun Park
Unlike conventional magnetic orders, topological spin textures in two-dimensional magnets show isotropic spin-wave speeds, offering a clear, general feature to identify topological order, aiding spintronics and magnetic materials discovery.
Phys. Rev. X 15, 031032 (2025)
Antiferromagnetism, Frustrated magnetism, Magnons, Skyrmions, Spin dynamics, Antiferromagnets, Noncollinear magnets, Holstein-Primakoff method, Landau-Lifshitz model, Langevin algorithm, Spin wave theory, Time-of-flight neutron spectroscopy
arXiv
Local texture of three-stage CVD SiC fibre by precession electron diffraction (PED) and XRD
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
B. Huang, Y. Q. Yang, M. H. Li, Y. X. Chen, X. Luo, M. S. Fu, Y. Chen, Xierong Zeng
SiC fibre with the transverse isotropic properties is very important to it reinforced metal matrix composites. In this paper, local texture of the CVD SiC fibre was investigated by means of X-ray diffraction (XRD) and precession electron diffraction (PED) on transmission electron microscopy(TEM). The result from XRD is in agreement with the result obtained from PED. And the result shown that at the first stage of deposition, the preferred direction of SiC grains is almost random and the distribution of grain size is scattered. At the second and third stages of deposition, there are two kinds of texture in SiC fibre, that is, (110),111. and (110),115.. Furthermore, the grain size at the second and third stages is about 200 nm and it is lower at the third stage than at the second stage because of the lower temperature at the third stage. The [110] preferred direction along axial direction for SiC fibre is beneficial to the axial tensile strength.
Materials Science (cond-mat.mtrl-sci)
Materials Science and Technology, 2014 VOL 30 NO 14 1751
Exploiting solute segregation and partitioning to the deformation-induced planar defects and nano-martensite in designing ultra-strong Co-Ni base alloys
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
Akshat Godha, Mayank Pratap Singh, Karthick Sundar, Shashwat Kumar Mishra, Praveen Kumar, Govind B, Surendra Kumar Makineni
Single-phase, multi-elements (three or more) with high concentrations show exceptional tensile strength up to ~ 0.8-1.2 GPa. However, they possess a very low 0.2% yield strength (YS), i.e., they can be permanently deformed at very low-stress levels of 300 to 600 MPa. Here, we reveal by exploiting atomic-scale solute interactions with the deformation-induced structures to design ultra-strong single-phase alloys with YS > 2 GPa. This was achieved by controlled thermomechanical processing that introduces stacking-faults (SFs), nano-twins (NTs), and nano-martensite {\epsilon}-laths (NMLs) during cold deformation followed by facilitating solute segregation/partitioning to them by tempering at intermediate temperature. We demonstrate the phenomena in a low stacking faulty energy multi-component (face-centered-cubic, fcc structured) Co-33Ni-24Cr alloy (all in at.%) containing 5at.% Mo as a solute. It is also shown that the degree of strengthening after tempering scales up with the fraction of these structures (before tempering) in the alloy microstructure that can be tuned by the amount and temperature of cold deformation. Cold-rolling with 45% and 65% thickness reduction, followed by tempering at 600°C for 4 hours, led to an YS of 1.5 GPa and 2 GPa with elongation to fracture (%El) 14% and 7%, respectively. The YS is further enhanced to ~ 2.2 GPa without reduction in %El upon cryo-rolling followed by tempering. The alloy microstructure is stable at 600°C up to 100 hours and also retains an YS of ~ 1.5 GPa with %El of 18% during tensile test at 600°C. The derived high YS and high-temperature stability are critically a consequence of solute partitioning to the NMLs that we termed as Solute-Partitioned NMLs (SP-NMLs) in the microstructure.
Materials Science (cond-mat.mtrl-sci)
Modelling hydrogen storage in metal hydrides
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
Francesc Font, Attila Husar, Tim Myers, Maria Aguareles, Esther Barrabés
We develop a one-dimensional mathematical model for the loading process of hydrogen in a metal hydride tank. The model describes the evolution of the density and pressure of the hydrogen gas, the temperature of the tank, the averaged velocity of the gas through the porous metal structure, and the transformed fraction of metal into a metal hydride. The non-dimensionalisation of the model indicates a possible reduction of the system of equations and also shows that the density and the transformed metal fraction may be decoupled from the temperature equation. The reduced model is solved numerically. Introducing a spatial dependence into the kinetic reaction constant allows to explain unexpected temperature gradients observed in experiments.
Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
Phases of Interacting Fibonacci Anyons on a Ladder at Half-Filling
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-31 20:00 EDT
Nico Kirchner, Roderich Moessner, Frank Pollmann, Adam Gammon-Smith
Two-dimensional many-body quantum systems can exhibit topological order and support collective excitations with anyonic statistics different from the usual fermionic or bosonic ones. With the emergence of these exotic point-like particles, it is natural to ask what phases can arise in interacting many-anyon systems. To study this topic, we consider the particular case of Fibonacci anyons subject to an anyonic tight-binding model with nearest-neighbor repulsion on a two-leg ladder. Focusing on the case of half-filling, for low interaction strengths an ‘’anyonic’’ metal is found, whereas for strong repulsion, the anyons form an insulating charge-density wave. Within the latter regime, we introduce an effective one-dimensional model up to sixth order in perturbation theory arising from anyonic superexchange processes. We numerically identify four distinct phases of the effective model, which we characterize using matrix product state methods. These include both the ferro- and antiferromagnetic golden chain, a $ \mathbb{Z}_2$ phase, and an incommensurate phase.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
14 pages, 8 figures
Probing Tensor Monopoles and Gerbe Invariants in Three-Dimensional Topological Matter
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-31 20:00 EDT
Wojciech J. Jankowski, Robert-Jan Slager, Giandomenico Palumbo
We show that momentum-space tensor monopoles corresponding to nontrivial vector bundle generalizations, known as bundle gerbes, can be realized in bands of three-dimensional topological matter with nontrivial Hopf invariants. We provide a universal construction of tensor Berry connections in these topological phases, demonstrating how obstructions therein lead to $ \mathbb{Z}$ -quantized bulk magnetoelectric and nonlinear optical phenomena. We then pinpoint that these quantum effects are supported by intraband and interband torsion leading to nontrivial Dixmier-Douady classes in most known Hopf phases and in more general topological insulators realizing gerbe invariants falling beyond the tenfold classification of topological phases of matter. We furthermore provide an interacting generalization upon introducing many-body gerbe invariants by employing twisted boundary conditions. This opens an avenue to study gerbe invariants realized through higher-dimensional charge fractionalizations that can be electromagnetically probed.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics), Quantum Physics (quant-ph)
8+6 pages, 3 figures
What is the topological dual of the XXZ spin Chain?
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-31 20:00 EDT
Yicheng Tang, Pradip Kattel, Natan Andrei
We construct a dual symmetry-protected topological (SPT) Hamiltonian for the $ U(1)$ symmetric anisotropic spin-$ \frac{1}{2}$ Heisenberg chain-a model that has traditionally been used to study spontaneous symmetry breaking (SSB) in both ferromagnetic and antiferromagnetic phases, with an intervening extended Luttinger liquid phase. By performing a non-local unitary transformation, we explicitly construct a local fermionic Hamiltonian that exhibits two nontrivial topological phases separated by an extended Luttinger liquid regime. We demonstrate the topological nature of these phases by analyzing the entanglement structure, deriving a non-local string order parameter, and constructing an exact zero mode operator that connects states in different fermionic parity sectors.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech), Mathematical Physics (math-ph), Quantum Physics (quant-ph)
4 pages, 4 figures
Chiral Wigner crystal phases induced by Berry curvature
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-31 20:00 EDT
Sandeep Joy, Leonid Levitov, Brian Skinner
We consider the impact of Berry phase on the Wigner crystal (WC) state of a two-dimensional electron system. We consider first a model of Bernal bilayer graphene with a perpendicular displacement field, and we show that Berry curvature leads to a new kind of WC state in which the electrons acquire a spontaneous orbital angular momentum when the displacement field exceeds a critical value. We determine the phase boundary of the WC state in terms of electron density and displacement field at low temperature. We then derive the general effective Hamiltonian that governs the ordering of the physical electron spin. We show that this Hamiltonian includes a chiral term that can drive the system into chiral spin-density wave or spin liquid phases. The phenomena we discuss are relevant for the valley-polarized Wigner crystal phases observed in multilayer graphene.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
7+9 pages, 3+1 figures. arXiv admin note: substantial text overlap with arXiv:2310.07751
How transparent is graphene? A surface science perspective on remote epitaxy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
Zach LaDuca, Anshu Sirohi, Quinn Campbell, Jason K Kawasaki
Remote epitaxy is the synthesis of a single crystalline film on a graphene-covered substrate, where the film adopts epitaxial registry to the substrate as if the graphene is transparent. Despite many exciting applications for flexible electronics, strain engineering, and heterogeneous integration, an understanding of the fundamental synthesis mechanisms remains elusive. Here we offer a perspective on the synthesis mechanisms, focusing on the foundational assumption of graphene transparency. We highlight challenges for quantifying the strength of the remote substrate potential that permeates through graphene, and propose Fourier and beating analysis as a bias-free method for decomposing the lattice potential contributions from the substrate, from graphene, and from surface reconstructions, each at different frequencies. We highlight the importance of graphene-induced reconstructions on epitaxial templating, drawing comparison to moiré epitaxy. Finally, we highlight the role of the remote potential in tuning surface diffusion and adatom kinetics on graphene. Tuning the surface diffusion length is crucial in navigating the competition between remote epitaxy and defect-seeded mechanisms like pinhole epitaxy.
Materials Science (cond-mat.mtrl-sci)
Continuous transition from Fermi liquid to A fractional Chern insulator
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-31 20:00 EDT
Recent experiments in moiré materials have observed fractional Chern insulators (FCI) at zero magnetic field, providing an opportunity to study the transition from FCI to the more conventional phases such as Fermi liquid (FL) and superconductor (SC) by tuning the interaction strength or bandwidth. In this work, we formulate a critical theory for a continuous transition at the filling $ \nu=\frac{2}{3}$ between the FL and a FCI\ast phase that hosts an additional neutral sector, but has the same transport signatures as the usual FCI. In our framework, this corresponds to a transition from a composite Fermi liquid (CFL) to a superfluid\ast phase of the composite bosons. The Fermi liquid close to the transition has an additional factor $ |z_i-z_j|^6$ in its wavefunction. Also, the transport behavior at high temperature on the FL side is actually like an `anyon gas’ phase on top of the FCI, with $ \rho_{xy}$ close to $ \frac{3}{2}\frac{h}{e^2}$ . FL behavior with $ \rho_{xy} \approx 0$ is recovered only at very low temperature. We also briefly discuss the possibility of a chiral superconductor as the descendant of this strongly correlated FL and the potential relevance to the twisted MoTe$ _2$ system.
Strongly Correlated Electrons (cond-mat.str-el)
6+4 pages; 1+1 figures
calcQPI: A versatile tool to simulate quasiparticle interference
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-31 20:00 EDT
Peter Wahl, Luke C. Rhodes, Carolina A. Marques
Quasiparticle interference imaging (QPI) provides a route to characterize electronic structure from real space images acquired using scanning tunneling microscopy. It emerges due to scattering of electrons at defects in the material. The QPI patterns encode details of the $ k$ -space electronic structure and its spin and orbital texture. Recovering this information from a measurement of QPI is non-trivial, requiring modelling not only of the dominant scattering vectors, but also the overlap of the wave functions with the tip of the microscope. While, in principle, it is possible to model QPI from density functional theory (DFT) calculations, for many quantum materials it is more desirable to model the QPI from a tight-binding model, where inaccuracies of the DFT calculation can be corrected. Here, we introduce an efficient code to simulate quasiparticle interference from tight-binding models using the continuum Green’s function method.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
32 pages including appendix, 12 figures, accompanies public release of calcQPI code at this https URL
Persistent spin currents in superconducting altermagnets
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-31 20:00 EDT
Kyle Monkman, Joan Weng, Niclas Heinsdorf, Alberto Nocera, Marcel Franz
Superconductors are famously capable of supporting persistent electrical currents, that is, currents that flow without any measurable decay as long as the material is kept in the superconducting state. We introduce here a class of materials – superconducting altermagnets – that can both generate and carry persistent {\em spin} currents. This includes spin-polarized electrical supercurrent as well as pure spin supercurrent that facilitates spin transport in the absence of any charge transport. A key to this remarkable property is the realization that the leading superconducting instability of altermagnetic metals consists of two independent condensates formed of spin-up and spin-down electrons. In the non-relativistic limit the two condensates are decoupled and can thus naturally support persistent currents with any spin polarization, including pure spin supercurrents realized in the charge counterflow regime. We describe a novel ``spin-current dynamo effect’’ that can be used to generate pure spin supercurrent in such systems by driving a charge current along certain crystallographic directions. Away from the non-relativistic limit, when spin-orbit interactions and magnetic disorder are present, we find that the spin current generically develops spatial oscillations but, importantly, no dissipation or decay. This is in stark contrast to spin currents in normal diffusive metals which tend to decay on relatively short lengthscales. We illustrate the above properties by performing model calculations relevant to two distinct classes of altermagnets and various device geometries.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
13 pages + appendices, 8 figures
Rheological modeling with GENERIC and with the Onsager principle
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-31 20:00 EDT
In this paper we compare three frameworks for modeling flows of complex fluids: (i) local conservations of mass, momentum and energy, (ii) GENERIC, and (iii) Onsager principle. The first is based on the mass, momentum, and energy conservation implied by mechanics, the second on the observed approach of externally unforced fluids to equilibrium states at which their behavior is well described by equilibrium thermodynamics, and the third on the minimal resistance to external influences. The comparison is illustrated on isothermal and incompressible polymeric fluids.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
10 pages, no figures
Emergent interactions lead to collective frustration in robotic matter
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-31 20:00 EDT
Onurcan Bektas, Adolfo Alsina, Steffen Rulands
Current artificial intelligence systems show near-human-level capabilities when deployed in isolation. Systems of a few collaborating intelligent agents are being engineered to perform tasks collectively. This raises the question of whether robotic matter, where many learning and intelligent agents interact, shows emergence of collective behaviour. And if so, which kind of phenomena would such systems exhibit? Here, we study a paradigmatic model for robotic matter: a stochastic many-particle system in which each particle is endowed with a deep neural network that predicts its transitions based on the particles’ environments. For a one-dimensional model, we show that robotic matter exhibits complex emergent phenomena, including transitions between long-lived learning regimes, the emergence of particle species, and frustration. We also find a density-dependent phase transition with signatures of criticality. Using active matter theory, we show that this phase transition is a consequence of self-organisation mediated by emergent inter-particle interactions. Our simple model captures key features of more complex forms of robotic systems.
Soft Condensed Matter (cond-mat.soft), Robotics (cs.RO)
Spatially-periodic states in a strongly dipolar $^{164}$Dy-$^{162}$Dy mixture
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-07-31 20:00 EDT
We demonstrate the formation of a novel eigenstate in a strongly dipolar binary $ ^{164}$ Dy-$ ^{162}$ Dy mixture, where the inter- and intraspecies dipolar lengths are larger than the corresponding scattering lengths. When this mixture is confined by a quasi-two-dimensional harmonic trap, the total density exhibits the formation of droplets on a spatially-symmetric triangular or square lattice, where each droplet is formed of a single species of atoms; two types of atoms never exist on the same lattice site. The density of any of the species shows a partially-filled incomplete lattice, only the total density exhibits a completely full lattice structure. In this theoretical investigation we employ the numerical solution of an improved mean-field model including a Lee-Huang-Yang-type interaction in the intraspecies components alone, meant to stop a collapse of the atoms at high atom density.
Quantum Gases (cond-mat.quant-gas)
Large magnon dichroism and other optical properties of hexagonal ferrite h-Lu0.6Sc0.4FeO3 with altermagnetic A2 spin ordering
New Submission | Other Condensed Matter (cond-mat.other) | 2025-07-31 20:00 EDT
V. A. Martinez (1), A. A. Sirenko (1), L. Bugnon (2), P. Marsik (2), C. Bernhard (2), Qing Zhang (3), G. L. Pascut (4), F. Lyzwa (1 and 5), Z. Liu (6), K. Du (7), S.-W. Cheong (7) ((1) Department of Physics, New Jersey Institute of Technology, (2) Department of Physics, University of Fribourg, (3) School of Physics, Shandong University, (4) MANSiD Research Center and Faculty of Forestry, Stefan Cel Mare University (USV), (5) NSLS-II, Brookhaven National Laboratory, (6) Department of Physics, University of Illinois at Chicago, (7) Keck Center for Quantum Magnetism and Department of Physics and Astronomy)
Multiferroic hexagonal h-Lu0.6Sc0.4FeO3 single crystals with non-collinear spins were studied using the THz and Raman scattering spectroscopies and ellipsometry. Antiferromagnetic resonances, or magnons, were found at about 0.85 THz and 1.2 THz. These magnons harden as temperature increases and disappear above 130 K. This behavior is consistent with the magnetic susceptibility and a phase transition to a previously reported weak ferromagnetic state. A strong dichroism at the resonance with the AFM doublet has been observed at zero external magnetic field using both conventional circular polarization and THz vector vortex beams. This observation is attributed to the strong altermagnetic properties of h-Lu0.6Sc0.4FeO3 with a broken PT symmetry. The splitting of the magnon doublet in an external magnetic field applied long the c axis yields a g-factor of 3.0 for the Fe3+ ions. Raman spectra of the optical phonons revealed a Fano-type asymmetry due to their interaction with a continuum of polar excitations. Electronic transitions were studied with ellipsometry and the results were compared with the modelled using DFT+eDMFT.
Other Condensed Matter (cond-mat.other), Optics (physics.optics)
Self-propulsion symmetries determine entropy production of active particles with hidden states
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-31 20:00 EDT
Jacob Knight, Farid Kaveh, Gunnar Pruessner
Entropy production distinguishes equilibrium from non-equilibrium. Calculating the entropy production rate (EPR) is challenging in systems where some degrees of freedom cannot be observed. Here we introduce a perturbative framework to calculate the ``partial EPR’’ of a canonical hidden-state system, a generic self-propelled active particle with hidden self-propulsion. We find that the parity symmetry, P, and (time-)reversibility, T, of the hidden variable determine partial entropy production. Non-trivial entropy production appears at least at sixth order in the self-propulsion velocity. We apply our framework to two processes which break P- and T-symmetries respectively: an asymmetric telegraph process and diffusion with stochastic resetting.
Statistical Mechanics (cond-mat.stat-mech)
6 pages main text, 1 figure, 10 pages supplement,
Better Together: Cross and Joint Covariances Enhance Signal Detectability in Undersampled Data
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-07-31 20:00 EDT
Arabind Swain, Sean Alexander Ridout, Ilya Nemenman
Many data-science applications involve detecting a shared signal between two high-dimensional variables. Using random matrix theory methods, we determine when such signal can be detected and reconstructed from sample correlations, despite the background of sampling noise induced correlations. We consider three different covariance matrices constructed from two high-dimensional variables: their individual self covariance, their cross covariance, and the self covariance of the concatenated (joint) variable, which incorporates the self and the cross correlation blocks. We observe the expected Baik, Ben Arous, and Péché detectability phase transition in all these covariance matrices, and we show that joint and cross covariance matrices always reconstruct the shared signal earlier than the self covariances. Whether the joint or the cross approach is better depends on the mismatch of dimensionalities between the variables. We discuss what these observations mean for choosing the right method for detecting linear correlations in data and how these findings may generalize to nonlinear statistical dependencies.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Machine Learning (cs.LG), Data Analysis, Statistics and Probability (physics.data-an), Machine Learning (stat.ML)
Understanding the fill-factor limit of organic solar cells
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
Huotian Zhang, Jun Yuan, Tong Wang, Nurlan Tokmoldin, Rokas Jasiunas, Yiting Liu, Manasi Pranav, Yuxuan Li, Xiaolei Zhang, Vidmantas Gulbinas, Safa Shoaee, Yingping Zou, Veaceslav Coropceanu, Artem A. Bakulin, Dieter Neher, Thomas Kirchartz, Feng Gao
Although the power conversion efficiencies of organic solar cells (OSCs) have surpassed 20%, they still lag behind commercial inorganic solar cells and emerging perovskite solar cells. To bridge this efficiency gap, improving the fill factor (FF) is critical, provided other photovoltaic parameters are not compromised. However, the fundamental understanding of the FF in OSCs remains incomplete. In this work, we systematically investigate a wide range of OSCs with the FF values spanning 0.27 to 0.80, and analyse the effect of free charge generation and recombination on the FF in OSCs. To explain our observations, we developed an analytical model that quantitatively correlates the applied electric field with the energetics of excited states in donor-acceptor blends. By combining device characterisation, spectroscopy, and theoretical modelling, we reveal that the Stark effect and the field-dependent charge transfer significantly impact the FF in state-of-the-art OSCs with low voltage losses. Our findings highlight that suppressing geminate decay by increasing exciton lifetime is a promising strategy for boosting the FF and achieving future efficiency gains in OSCs.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Steinberg-Guinan strength model for rhenium
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
Rhenium, Re, is used as an x-ray shield in laser-driven material property experiments, where its strength at high pressures can be a consideration in the design, modeling, and interpretation. We present a Steinberg-Guinan (SG) strength model for Re, tailored for use in high-pressure dynamic loading simulations. Parameters for the SG model were derived from recent atom-in-jellium predictions of the shear modulus under compression and experimental data on work-hardening from rolled-bar studies. The ambient shear modulus was fixed to the measured value, and the pressure-hardening parameter was fitted to the atom-in-jellium predictions up to 1 TPa. The shear modulus model was still a reasonable fit beyond 25 TPa. Thermal softening was estimated from the thermal expansivity and bulk modulus. Work-hardening parameters were extracted by fitting the model to Knoop microhardness measurements under known plastic strains. The resulting model captures the observed hardening behavior but predicts significantly lower flow stresses at high pressures than diamond anvil cell observations suggest, implying that Re may exhibit enhanced strength at megabar pressures. These results provide a basis for improved modeling of strength in Re under extreme conditions and suggest directions for further theoretical and experimental investigation.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
Ultrafast Faraday Rotation Probe of Chiral Phonon-Polaritons in LiNbO3
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-31 20:00 EDT
Megan F. Biggs, Sin-hang (Enoch)Ho, Aldair Alejandro, Matthew Lutz, Clayton D. Moss, Jeremy A. Johnson
Time reversal symmetry breaking motion of chiral phonon-polaritons in LiNbO3 is probed via the ultrafast Faraday effect. By combining a pair of perpendicularly polarized THz pulses with the right relative delay, we create a chiral THz driving field to excite chiral phonon-polaritons. The chiral atomic motion combines with the inverse Faraday effect from the circularly polarized THz pump to induce a magnetic moment field in the nonmagnetic material, LiNbO3. We attempt to quantify the strength of the magnetic field with Faraday rotation probe measurements. The direction of the Faraday signal flips when the input THz pulse is changed from left- to right-circular polarization, and we estimate a strong induced magnetic field strength of ~11 Tesla based on the Faraday rotation.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph)
15 pages, 11 figures
Fabrication of microstructured devices of the unconventional superconductor CeCoIn5 for investigations of isolated grain boundaries
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-31 20:00 EDT
Sanu Mishra, Sean M. Thomas, Rod Mccabe, Eric D. Bauer, Filip Ronning
Grain boundaries are critical for determining the functionality of polycrystalline materials. Here we present on the structural $ &$ transport properties of grain boundaries in the unconventional superconductor CeCoIn$ _5$ . We provide a detailed recipe for the fabrication of isolated grain boundary devices from of as-grown polycrystalline samples of CeCoIn$ _5$ . Electron backscattered diffraction imaging of polycrystalline CeCoIn$ _5$ samples reveals an abundance of $ 90^\circ$ misorientation grain boundaries suggesting a preferential nucleation of CeCoIn$ _5$ grains with 90$ ^\circ$ misorientation over a random distribution of grain orientations. Transport measurements across grain boundary devices establish coherence of superconductivity and allows us to establish a lower bound on the critical current density for the grain boundaries. Our work opens new possibilities for fabrication of quantum devices such as Josephson-junctions out of bulk unconventional superconducting materials.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
12 pages, 12 figures
Magnetic Excitations of a Half-Filled Tl-based Cuprate
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-31 20:00 EDT
I. Biało, Q. Wang, J. Küspert, X. Hong, L. Martinelli, O. Gerguri, Y. Chan, K. von Arx, O. K. Forslund, W. R. Pudełko, C. Lin, N. C. Plumb, Y. Sassa, D. Betto, N. B. Brookes, M. Rosmus, N. Olszowska, M. D. Watson, T. K. Kim, C. Cacho, M. Horio, M. Ishikado, H. M. Rønnow, J. Chang
Strong electron correlations drive Mott insulator transitions. Yet, there exists no framework to classify Mott insulators by their degree of correlation. Cuprate superconductors, with their tunable doping and rich phase diagrams, offer a unique platform to investigate the evolution of those interactions. However, spectroscopic access to a clean half-filled Mott-insulating state is lacking in compounds with the highest superconducting onset temperature. To fill this gap, we introduce a pristine, half-filled thallium-based cuprate system, Tl$ _2$ Ba$ _5$ Cu$ _4$ O$ _{10+x}$ (Tl2504). Using high-resolution resonant inelastic x-ray scattering (RIXS), we probe long-lived magnon excitations and uncover a pronounced kink in the magnon dispersion, marked by a simultaneous change in group velocity and lifetime broadening. Modeling the dispersion within a Hubbard-Heisenberg approach, we extract the interaction strength and compare it with other cuprate systems. Our results establish a cuprate universal relation between electron-electron interaction and magnon zone-boundary dispersion. Superconductivity seems to be optimal at intermediate correlation strength, suggesting an optimal balance between localization and itinerancy.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
10 pages, 5 figures, 2 tables
Magnetism of kagome metals $\left(\text{Fe}{1-x} \text{Co}{x}\right) \text{Sn}$ studied by $μ$SR
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-31 20:00 EDT
Yipeng Cai, Sungwon Yoon, Qi Sheng, Guoqiang Zhao, Eric Francis Seewald, Sanat Ghosh, Julian Ingham, Abhay Narayan Pasupathy, Raquel Queiroz, Hechang Lei, Yaofeng Xie, Pengcheng Dai, Takashi Ito, Ruyi Ke, Robert J. Cava, Sudarshan Sharma, Mathew Pula, Graeme M. Luke, Kenji M. Kojima, Yasutomo J. Uemura
We study the magnetic properties of the metallic kagome system $ \left(\mathrm{Fe}{1-x} \mathrm{Co}{x}\right) \mathrm{Sn}$ by a combination of Muon Spin Relaxation ($ \mu \mathrm{SR}$ ), magnetic susceptibility and Scanning Tunneling Microscopy (STM) measurements, in single crystal specimens with Co concentrations $ \mathrm{x}=0,0.11,0.8$ . In the undoped antiferromagnetic compound FeSn, we find possible signatures for a previously unidentified phase that sets in at $ T^\ast\sim 50$ K, well beneath the Neel temperature $ T_N \sim 376$ K, as indicated by a peak in the relaxation rate $ 1/T_1$ observed in zero field (ZF) and longitudinal field (LF) $ \mu \mathrm{SR}$ measurements, with a corresponding anomaly in the ac and dc-susceptibility, and an increase in the static width $ 1/T_2$ in ZF measurements. No signatures of spatial symmetry breaking are found in STM down to $ 7$ K. In $ \mathrm{Fe}{0.2} \mathrm{Co}{0.8} \mathrm{Sn}$ , we find canonical spin glass behavior with freezing temperature $ T_{g} \sim 3.5 \mathrm{~K}$ ; the ZF and LF time spectra exhibit results similar to those observed in dilute alloy spin glasses CuMn and AuFe, with a critical behavior of $ 1 / T_{1}$ at $ T_{g}$ and $ 1 / \mathrm{T}_{1}\rightarrow 0$ as $ T \rightarrow 0$ . The absence of spin dynamics at low temperatures makes a clear contrast to the spin dynamics observed by $ \mu \mathrm{SR}$ in many geometrically frustrated spin systems on insulating kagome, pyrochlore, and triangular lattices. The spin glass behavior of CoSn doped with dilute Fe moments is shown to originate primarily from the randomness of doped Fe moments rather than due to geometrical frustration of the underlying lattice.
Strongly Correlated Electrons (cond-mat.str-el)
Phys. Rev. B 111, 214412 (2025)
Scan calculation of the density of states: real space cluster perturbation theory applied to inhomogeneous Hubbard model in one dimension
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-31 20:00 EDT
Kaito Matsuki, Chisa Hotta, Kenichi Asano
We present the spectral analysis of a one-dimensional Hubbard model with a parabolic potential, using a real-space cluster perturbation theory (rCPT) designed to study spatially inhomogeneous electron systems with strong correlation. It is a natural extension of the conventional CPT to inhomogeneous cases by computing local Green’s functions while averaging over multiple cluster boundaries. We find that the local density of states of at each site mirrors that of a homogeneous system with the same local filling. This insight offers a perspective on spectral evolution in inhomogeneous systems used to scan the occupancy-dependent features of the homogeneous system, making this setup a practical one-shot spectroscopy tool for ultracold atoms in harmonic traps.
Strongly Correlated Electrons (cond-mat.str-el)
11pages 5figures
Phys. Rev. B, 112, 045146 (2025)
Strain effects on the fluctuation properties in noncollinear antiferromagnets: a first-principles and macrospin-based study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
Mohammad M. Rahman, Farzad Mahfouzi, Matthew W. Daniels, Mark D. Stiles
We present a theoretical investigation of epitaxial strain effects on the magnetic fluctuation properties of Mn$ _3$ Sn noncollinear antiferromagnets. Employing density functional theory (DFT), we uncover significant strain-induced modifications to key magnetic parameters, including magnetic anisotropy and both bilinear and biquadratic exchange interactions. Our findings reveal that the biquadratic exchange, often neglected, plays a crucial role in defining the magnetic energy landscape and its response to strain. These microscopic changes directly impact the energy barriers governing magnetic switching, thereby influencing thermal stability and fluctuation rates. Using macrospin-based simulations based on DFT-derived parameters, we provide a quantitative analysis of the macroscopic magnetic fluctuations influenced by these microscopic interactions. These insights are particularly relevant for applications requiring precisely controlled magnetic behavior, such as hardware for probabilistic computing.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph)
Bulk Nanostructured Zirconia Ceramics with High Hardness and Toughness via Integration of High-Pressure Torsion and Spark Plasma Sintering
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
Kaveh Edalati, Koji Morita, Shivam Dangwal, Zenji Horita
Developing nanostructured bulk ceramics is a major challenge when conventional high-temperature sintering is employed for consolidation. In the current investigation, yttria-stabilized zirconia (YSZ) with a composition of ZrO2 - 3 mol% Y2O3 is first treated using high-pressure torsion (HPT) and further consolidated using spark plasma sintering (SPS) to produce a nanostructured bulk sample. The material demonstrates phase transformations from tetragonal to dislocation-decorated monoclinic by HPT and reversely transforms to the tetragonal phase after the SPS process while maintaining a mean grain size of 80 nm and large numbers of dislocations. The consolidated ceramic exhibits a density of 6.07 g/cm3 (99% relative density) with a high hardness of 1500 Hv, which is reasonably consistent with the prediction of the Hall-Petch relationship. Examination of the indented areas during the hardness test confirms the absence of cracks, indicating good fracture toughness (KIC) because of the presence of dislocations, while the sample processed only by SPS and without HPT processing forms numerous cracks by indentation and exhibits low KIC.
Materials Science (cond-mat.mtrl-sci)
Monopole Traps for Position-Based Information Coding
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-31 20:00 EDT
Prakash Timsina, Andres Chappa, Deema Alyones, Boris Kiefer, Ludi Miao
We propose a spin-ice-based heterostructure capable of encoding magnetic monopole quasiparticle positions for non-volatile information storage applications. Building upon two-dimensional magnetic monopole gases formed at the interface between 2-in-2-out spin ice and all-in-all-out antiferromagnetic pyrochlore iridate, the design introduces a 3-in-1-out/1-in-3-out fragmented barrier layer into the spin-ice matrix, defining two energetically stable monopole traps. The occupancy of these traps can be deterministically controlled by an externally applied magnetic field. Monte Carlo simulations reveal robust bistable switching, thermal stability below 0.22 K, and fully reversible field-driven transitions, demonstrating the system’s potential for reliable, repeatable memory operation. Crucially, the heterostructure exhibits emergent ferromagnetism linked to monopole position, enabling non-destructive readout of the memory state via spatially resolved magnetic imaging. Unlike topological carriers such as skyrmions, monopoles confined at the sub-nanometer scale offer three orders of magnitude higher information density. These results establish these monopole-trap heterostructures as a scalable platform for next-generation ultra-compact memory technologies.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
7 pages, and 3 figures
Magnetoresistance in the Extreme Quantum Limit: Field-Induced Crossover to the Unitarity Limit
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
Shuto Tago, Akiyoshi Yamada, Yuki Fuseya
We theoretically investigate magnetoresistance (MR) in the extreme quantum limit (EQL), where the kinetic energy becomes significantly smaller than the cyclotron energy, using the Kubo formula with Green’s functions and the $ T$ -matrix approximation. We uncover a magnetic-field-induced crossover in the scattering rate: $ 1/\tau \propto B^2$ in the Born regime and $ 1/\tau \propto B^{-2}$ in the unitarity limit. This crossover gives rise to distinct MR behaviors in the EQL, characterized by linear transverse MR ($ \rho_{xx} \propto B$ ) and negative longitudinal MR ($ \rho_{zz} \propto B^{-2}$ ). This dichotomy implies insulating behavior when the magnetic field is perpendicular to the current, and metallic behavior when it is parallel. In the unitarity limit, we further derive a universal relation that enables direct experimental determination of the impurity density from $ \rho_{xx}$ and $ \rho_{xy}$ . Our results establish a quantum–classical correspondence that remains valid even in the EQL, provided that the field dependences of the scattering rate and quantum corrections are properly incorporated.
Materials Science (cond-mat.mtrl-sci)
Anisotropic Magnetism in Gd$_2$B$_5$
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-31 20:00 EDT
Maximilien F. Debbas, Takehito Suzuki, Alex H. Mayo, Mun K. Chan, Joseph G. Checkelsky
We report the synthesis of single crystals of Gd$ _2$ B$ _5$ through a ruthenium-gadolinium flux method. The Gd$ _2$ B$ _5$ system is a member of the monoclinic $ P21/c$ (No. 14) space group and realizes lattices of gadolinium atoms in the $ (1,0,0)$ plane. We characterized the sample through orientation-dependent electrical transport, magnetization, magnetic torque, and heat capacity measurements to probe the magnetic anisotropy of the system and map out its phase diagram. Gd$ _2$ B$ _5$ realizes two zero-field ordered phases M$ _1$ and M$ _2$ , as well as a third field-induced ordered phase M$ _\perp$ arising when the magnetic field is applied in the $ (1,0,0)$ plane.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
12 pages, 18 figures
Universal Magnetic Phases in Twisted Bilayer MoTe$_2$
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-31 20:00 EDT
Weijie Li, Evgeny Redekop, Christiano Wang Beach, Canxun Zhang, Xiaowei Zhang, Xiaoyu Liu, Will Holtzmann, Chaowei Hu, Eric Anderson, Heonjoon Park, Takashi Taniguchi, Kenji Watanabe, Jiun-haw Chu, Liang Fu, Ting Cao, Di Xiao, Andrea F. Young, Xiaodong Xu
Twisted bilayer MoTe$ _2$ (tMoTe$ _2$ ) has emerged as a robust platform for exploring correlated topological phases, notably supporting fractional Chern insulator (FCI) states at zero magnetic field across a wide range of twist angles. The evolution of magnetism and topology with twist angle remains an open question. Here, we systematically map the magnetic phase diagram of tMoTe$ _2$ using local optical spectroscopy and scanning nanoSQUID-on-tip (nSOT) magnetometry. We identify spontaneous ferromagnetism at moiré filling factors $ \nu = -1$ and $ -3$ over a twist angle range from 2.1$ ^\circ$ to 3.7$ ^\circ$ , revealing a universal, twist-angle-insensitive ferromagnetic phase. At 2.1$ ^\circ$ , we further observe robust ferromagnetism at $ \nu = -5$ , absent in the devices with larger twist angle – a signature of the flattening of higher bands in this twist angle range. Temperature-dependent measurements reveal a contrasting twist-angle dependence of the Curie temperatures between $ \nu = -1$ and $ \nu = -3$ , indicating distinct interplay between exchange interaction and bandwidth for the two Chern bands. Despite spontaneous time-reversal symmetry breaking, we find no evidence of a topological gap at $ \nu = -3$ ; however, fragile correlated topological phases could be obscured by the device disorder evident in our spatially resolved measurements. Our results establish a global framework for understanding and controlling magnetic order in tMoTe$ _2$ and highlight its potential for accessing correlated topological phases in higher energy Chern band.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
Quantum Criticality by Interaction Frustration in a Square-Planar Lattice
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-31 20:00 EDT
Yi-Qiang Lin, Chang-Chao Liu, Jia-Xin Li, Bai-Jiang Lv, Kai-Xin Ye, Jia-Wen Zhang, Si-Qi Wu, Ya-Nan Zhang, Ye Chen, Jia-Yi Lu, Jing Li, Hua-Xun Li, Hao Li, Yi Liu, Cao Wang, Yun-Lei Sun, Hao Jiang, Hui-Qiu Yuan, Guang-Han Cao
We report experimental and theoretical investigations on ThCr$ _2$ Ge$ _2$ C, a metallic compound in which Cr$ _2$ C planes form a square-planar lattice. Neutron powder diffraction, magnetization, and specific heat measurements reveal no evidence of long-range magnetic order or short-range spin freezing down to 70~mK. Quantum critical behavior was indicated through logarithmic divergences in both the magnetic susceptibility and the specific heat divided by temperature. Resistivity measurements exhibit non-Fermi-liquid behavior, with a Fermi liquid recovered under magnetic fields or high pressures. First-principles calculations identify competing nearest-neighbor ($ J_1$ ) and next-nearest-neighbor ($ J_2$ ) exchange interactions, with $ J_2/J_1 \sim -0.5$ , pointing to strong magnetic frustration. The interaction frustration is reduced, and magnetically ordered phases are stabilized upon the application of negative or positive pressures. This work offers a rare example of zero-field, ambient pressure quantum criticality mainly driven by interaction frustration in a square lattice.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
17 pages, 13 figures, and 6 tables
Transparency versus Anderson localization in one-dimensional disordered stealthy hyperuniform layered media
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-07-31 20:00 EDT
Michael A. Klatt, Paul J. Steinhardt, Salvatore Torquato
We present numerical simulations of disordered stealthy hyperuniform layered media ranging up to 10,000 thin slabs of high-dielectric constant separated by intervals of low dielectric constant that show no apparent evidence of Anderson localization of electromagnetic waves or deviations from transparency for a continuous band of frequencies ranging from zero up to some value $ \omega_T$ . The results are consistent with the strong-contrast formula including its tight upper bound on $ \omega_T$ and with previous simulations on much smaller systems. We utilize a transfer matrix method to compute the Lyaponov exponents, which we show is a more reliable method for detecting Anderson localization by applying it to a range of systems with common types of disorder known to exhibit localization, such as perturbed periodic lattices. The Lyaponov exponents for these systems with ordinary disorder show clear evidence of localization, in contrast to the cases of perfectly periodically spaced slabs and disordered stealthy hyperuniform layered systems. As with any numerical study, one should be cautious about drawing definitive conclusions. There remains the challenge of determining whether one-dimensional disordered stealthy hyperuniform layered media possess a finite localization length on some scale much larger than our already large system size or, alternatively, are exceptions to the standard Anderson localization theorems.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
18 pages, 5 figures, supplemental with 1 figure
Observation of Superconducting Solitons by Terahertz-Light-Driven Persistent Pseudo-Spin Coherence
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-31 20:00 EDT
M. Mootz, C. Vaswani, C. Huang, K. J. Lee, A. Khatri, P. Mandal, J. H. Kang, L. Luo, I. E. Perakis, C. B. Eom, J. Wang
Overcoming the decoherence bottleneck remains a central challenge for advancing coherent superconducting quantum device and information technologies. Solitons – non-dispersive wave packets stabilized by the collective synchronization of quantum excitations – offer a robust pathway to mitigating dephasing, yet their realization in superconductors has remained experimentally elusive. Here, we report the observation of a driven soliton state in epitaxial thin films of an iron-based superconductor (Co-doped BaFe$ _2$ As$ _2$ ), induced by intense, multi-cycle terahertz (THz) periodic driving. The dynamical transition to this soliton state is marked by the emergence of Floquet-like spectral sidebands that exhibit a strongly nonlinear dependence on THz laser field strength and a resonant enhancement with temperature. Quantum kinetic simulations corroborate these observations, allowing us to underpin the emergence of synchronized Anderson pseudo-spin oscillations – analogous to Dicke superradiance – mediated by persistent order parameter oscillations. In this coherently driven state, the observed sidebands result from difference-frequency mixing between the THz drive and persistent soliton dynamics. These findings establish a robust framework for coherently driving and controlling superconducting soliton time-crystal-like phases using low dissipation, time-periodic THz fields, enabling prospects for THz-speed quantum gate operations, long-lived quantum memory, and robust quantum sensing based on enhanced macroscopic pseudo-spin coherence.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
Sequential Circuit as Generalized Symmetry on Lattice
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-31 20:00 EDT
Nathanan Tantivasadakarn, Xinyu Liu, Xie Chen
Generalized symmetry extends the usual notion of symmetry to ones that are of higher-form, acting on subsystems, non-invertible, etc. The concept was originally defined in the field theory context using the idea of topological defects. On the lattice, an immediate consequence is that a symmetry twist is moved across the system by a sequential quantum circuit. In this paper, we ask how to obtain the full, potentially non-invertible symmetry action from the unitary sequential circuit and how the connection to sequential circuit constrains the properties of the generalized symmetries. We find that for symmetries that contain the trivial symmetry operator as a fusion outcome, which we call annihilable symmetries, the sequential circuit fully determines the symmetry action and puts various constraints on their fusion. In contrast, for unannihilable symmetries, like that whose corresponding twist is the Cheshire string, a further 1D sequential circuit is needed for the full description. Matrix product operator and tensor network operator representations play an important role in our discussion.
Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Theory (hep-th), Quantum Physics (quant-ph)
CLuP practically achieves $\sim 1.77$ positive and $\sim 0.33$ negative Hopfield model ground state free energy
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-07-31 20:00 EDT
We study algorithmic aspects of finding $ n$ -dimensional \emph{positive} and \emph{negative} Hopfield ($ \pm$ Hop) model ground state free energies. This corresponds to classical maximization of random positive/negative semi-definite quadratic forms over binary $ \left {\pm \frac{1}{\sqrt{n}} \right }^n$ vectors. The key algorithmic question is whether these problems can be computationally efficiently approximated within a factor $ \approx 1$ . Following the introduction and success of \emph{Controlled Loosening-up} (CLuP-SK) algorithms in finding near ground state energies of closely related Sherrington-Kirkpatrick (SK) models [82], we here propose a CLuP$ \pm$ Hop counterparts for $ \pm$ Hop models. Fully lifted random duality theory (fl RDT) [78] is utilized to characterize CLuP$ \pm$ Hop \emph{typical} dynamics. An excellent agreement between practical performance and theoretical predictions is observed. In particular, for $ n$ as small as few thousands CLuP$ \pm$ Hop achieve $ \sim 1.77$ and $ \sim 0.33$ as the ground state free energies of the positive and negative Hopfield models. At the same time we obtain on the 6th level of lifting (6-spl RDT) corresponding theoretical thermodynamic ($ n\rightarrow\infty$ ) limits $ \approx 1.7784$ and $ \approx 0.3281$ . This positions determining Hopfield models near ground state energies as \emph{typically} easy problems. Moreover, the very same 6th lifting level evaluations allow to uncover a fundamental intrinsic difference between two models: $ +$ Hop’s near optimal configurations are \emph{typically close} to each other whereas the $ -$ Hop’s are \emph{typically far away}.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Information Theory (cs.IT), Optimization and Control (math.OC), Machine Learning (stat.ML)
In-Plane Magnetic Anisotropy and Large topological Hall Effect in Self-Intercalated Ferromagnet Cr1.61Te2
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
Yalei Huang, Na Zuo, Zheyi Zhang, Xiangzhuo Xing, Xinyu Yao, Anlei Zhang, Haowei Ma, Chunqiang Xu, Wenhe Jiao, Wei Zhou, Raman Sankar, Dong Qian, Xiaofeng Xu
Self-intercalated chromium tellurides Cr1+xTe2 have garnered growing attention due to their high-temperature ferromagnetism, tunable spin structures and air stability, all of which are vital for versatile applications in next-generation memory and information technology. Here, we report strong magnetic anisotropy and a large topological Hall effect (THE) in self-intercalated Cr1.61Te2 single crystals, which are both highly desirable properties for future spintronic applications. Our results demonstrate that Cr1.61Te2 is a soft ferromagnet with strong in-plane magnetic anisotropy. Remarkably, distinct THE behaviors are observed in different temperature regimes, reflecting the intricate spin structures and competing exchange interactions. More interestingly, a large topological Hall resistivity, induced by microscopic non-coplanar spin structures, emerges in the temperature range 70-240 K, reaching a maximum value of 0.93 {\mu}{\Omega} cm at 150 K. Moreover, a sign-reversed and weak THE is observed at low temperatures below ~70 K, indicating the emergence of an additional topological spin structure with opposite topological charges. This work not only offers valuable insights into the correlation between magnetocrystalline anisotropy and topological phenomena in Cr1+xTe2 systems, but also provides a robust platform for engineering the evolution of complex spin textures that can be leveraged in diverse spintronic device applications.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
5 figures, 1 table
Adv. Funct. Mater. 2025, e10351
Phase Competition and Rutile Phase Stabilization of Growing GeO2 Films by MOCVD
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
Imteaz Rahaman, Botong Li, Hunter D. Ellis, Kathy Anderson, Feng Liu, Michael A. Scarpulla, Kai Fu
Rutile germanium dioxide (r-GeO2) is an ultra-wide bandgap semiconductor with potential for ambipolar doping, making it a promising candidate for next-generation power electronics and optoelectronics. Growth of phase-pure r-GeO2 films by vapor phase techniques like metalorganic chemical vapor deposition (MOCVD) is challenging because of polymorphic competition from amorphous and quartz GeO2. Here, we introduce seed-driven stepwise crystallization (SDSC) as a segmented growth strategy for obtaining r-GeO2 films on r-TiO2 (001) substrate. SDSC divides the growth into repeated cycles of film deposition and cooling-heating ramps, which suppress the non-rutile phases. We discuss the underlying mechanisms of phase selection during SDSC growth. We demonstrate continuous, phase-pure, partially epitaxial r-GeO2 (001) films exhibiting x-ray rocking curves with a FWHM of 597 arcsec. SDSC-based growth provides a generalizable pathway for selective vapor-phase growth of metastable or unstable phases, offering new opportunities for phase-selective thin-film engineering.
Materials Science (cond-mat.mtrl-sci)
Thermal Hall effect induced by phonon skew-scattering via orbital magnetization
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-31 20:00 EDT
Thermal transport acts as a powerful tool for studying the excitations and physical properties of insulators, where a charge gap suppresses electronic conduction. Recently, the thermal Hall effect has been observed across various materials, including insulators and semiconductors, but its fundamental origin remains unclear. Here, I propose a promising mechanism to explain the emergence of the thermal Hall effect in these systems: axial chiral phonon skew scattering mediated by orbital magnetization. Starting from basic principles, I derive the form and magnitude of the orbital magnetization-phonon coupling using the well-established Haldane model. Using this coupling, I calculate the thermal Hall conductivity and Hall angle as functions of temperature, achieving semi-quantitative agreement with experimental findings. This work enhances our understanding of the role of electron-phonon coupling in thermal transport and provides a pathway to tailor thermal properties in a broad range of materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
8 pages, 4 figures
Vortex Refraction at Tilted Superconductor-Normal Metal Interfaces
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-31 20:00 EDT
Matéo F. L. Roinard-Chauvet, Axel J. M. Deenen, Dirk Grundler
We derive a refraction law for superconducting vortices at superconductor/normal metal interfaces. Simulations of the proximity effect under tilted geometries confirm this law and reveal vortex trapping for low effective mass. Under transport currents, we find core displacements due to differing vortex viscosities in the superconductor and normal metal. These results clarify vortex dynamics in proximity-coupled systems and offer design principles for high-current coated superconducting devices.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Spray flame synthesis of Y2O3-MgO nanoparticles for mid-infrared transparent nanocomposite ceramics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
Shuting Lei, Yiyang Zhang, Xing Jin, Yanan Li, Zhu Fang, Shuiqing Li
Spray flame synthesis offers a promising method for scalable production of homogeneously mixed Y2O3-MgO nanopowders as next-generation infrared-transparent window material, which has attracted significant attention owing to its excellent optical properties at high temperatures. However, systematic understanding of how flame synthesis parameters influence particle morphology, crystal phase, solid solubility, and subsequent ceramic performance remains insufficiently understood. In this study, we investigated the influence of precursor chemistry on particle crystal phase and examined the solid solubility of MgO in Y2O3 under different flame temperatures, demonstrating that the high-temperature conditions with O2 as dispersion gas allow up to 50 mol% MgO to fully dissolve into Y2O3, far exceeding the equilibrium solubility limit of 7 mol% at the eutectic temperature (2100°C) and near-zero at room temperature. Furthermore, we systematically evaluated how powder characteristics and sintering parameters-including powder deagglomeration methods, vacuum sintering temperature, hot isostatic pressing (HIP) temperature, and initial powder characteristics-affect ceramic microstructures and infrared transmittance. Despite cracking induced by phase transformation and finer particle sizes, ceramics fabricated from oxygen-synthesized monoclinic-dominated powders exhibited superior near-infrared transmittance (56.2% at 1550 nm), attributed to enhanced atomic mixing and effective grain boundary pinning. After optimization, pure cubic phase powders produced intact and crack-free ceramics with outstanding mid-infrared transparency, achieving a maximum transmittance of 84.6% and an average transmittance of 82.3% in 3-5 um range.
Materials Science (cond-mat.mtrl-sci)
36 pages, 20 figures
Collective Fluorescence of Graphene Quantum Dots on a Halide Perovskite Crystal
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-31 20:00 EDT
Hugo Levy-Falk, Suman Sarkar, Thanh Trung Huynh, Daniel Medina-Lopez, Lauren Hurley, Océane Capelle, Muriel Bouttemy, Gaëlle Trippé-Allard, Stéphane Campidelli, Loïc Rondin, Elsa Cassette, Emmanuelle Deleporte, Jean-Sébastien Lauret
This study explores the dynamical collective fluorescence of $ C_{96}tBu_8$ graphene quantum dots when deposited on the surface of monocrystalline halide perovskite. Despite the tendency of the graphene quantum dots to avoid aggregation in solution and polymer matrices, our findings reveal distinct collective behaviors when deposited on the perovskite surface, here $ CH_3NH_3PbBr_3$ . We observed small clusters of graphene quantum dots rather than isolated single molecules through confocal fluorescence microscopy. Spectral analysis under continuous illumination shows a back-and-forth dynamical transition between an uncoupled, monomer-like state and a coupled state with a redshifted emission. In some cases, this dynamical process is followed by a drastic one-way increase in fluorescence intensity combined with a shortening of the excited state lifetime, which could characterize the emission of ordered graphene quantum dots within aggregates.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Atomic and Molecular Clusters (physics.atm-clus)
Proposal for realizing Heisenberg-type quantum-spin models in Rydberg atom quantum simulators
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-07-31 20:00 EDT
Masaya Kunimi, Takafumi Tomita
We investigate the magnetic-field dependence of the interaction between two Rydberg atoms, $ |nS_{1/2}, m_J\rangle$ and $ |(n+1)S_{1/2}, m_J\rangle$ . In this setting, the effective spin-1/2 Hamiltonian takes the form of an {\it XXZ} model. We show that the anisotropy parameter of the {\it XXZ} model can be tuned by applying a magnetic field, and in particular, that it changes drastically near the Förster resonance points. Based on this result, we propose experimental realizations of spin-1/2 and spin-1 Heisenberg-type quantum spin models in Rydberg atom quantum simulators, without relying on Floquet engineering. Our results provide guidance for future experiments of Rydberg atom quantum simulators and offer insight into quantum many-body phenomena emerging in the Heisenberg model.
Quantum Gases (cond-mat.quant-gas), Statistical Mechanics (cond-mat.stat-mech), Strongly Correlated Electrons (cond-mat.str-el), Atomic Physics (physics.atom-ph), Quantum Physics (quant-ph)
main: 10 mages, 4 figures, supplemental material: 17 pages, 13 figures, 10 tables
Strain-Controlled Topological Phase Transitions and Chern Number Reversal in Two-Dimensional Altermagnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-31 20:00 EDT
Zesen Fu, Mengli Hu, Aolin Li, Haiming Duan, Junwei Liu, Fangping Ouyang
We present a theoretical and first-principles study of a two-dimensional altermagnet exhibiting spin-valley locking and strain-tunable topological phases. By constructing a minimal tight-binding model constrained by altermagnetic symmetry, we show that biaxial strain can drive a transition from a trivial insulator to a type-II quantum spin Hall (QSH) phase. Furthermore, we derive an analytical strain-induced perturbation theory that identifies two critical curves, dividing the phase space into four regions corresponding to a trivial insulator, a type-II QSH phase, and two quantum anomalous Hall phases with opposite Chern numbers. Remarkably, the Chern number can be reversed purely by changing the strain direction –without modifying magnetization or applying magnetic fields. The model reveals a universal phase diagram for materials with the same symmetry and valley structure. First-principles calculations on monolayer CrO confirm the predicted topological transitions, establishing strain engineering as an effective route for topological control in two-dimensional altermagnetic materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
6 pages, 4 figures
Unconventional spin texture driven by higher-order spin-orbit interactions
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
Jiaxuan Wu, Boyun Zeng, Hanghui Chen
Spin splitting and the resulting spin texture are central to emerging spintronic applications. In non-centrosymmetric non-magnetic materials containing heavy elements, spin textures are typically governed by low-order, momentum-dependent spin-orbit interactions, such as Rashba spin-orbit interaction with linear or cubic order in crystal momentum. In this work, we use \textit{ab initio} calculations to reveal a previously unidentified spin texture in the conduction bands of a prototypical ferroelectric nitride LaWN$ 3$ . In addition to the usual $ \Gamma$ -centered vortex, we find six new vortices and anti-vortices located at non-high-symmetry points near the Brillouin zone center. Furthermore, by combining group-theoretical analysis and $ \textbf{k}\cdot\textbf{p}$ perturbation modeling, we show that, constrained by the $ C{3v}$ point group to which ferroelectric LaWN$ _3$ belongs, a 7th-order Weyl spin-orbit interaction is essential to reproduce the unconventional spin structure observed in first-principles calculations. We also find that weak electron doping of LaWN$ _3$ leads to a Fermi surface whose spin-arrow contour exhibits an unusual epicycloid pattern–a distinctive signature that is experimentally accessible. Our work demonstrates that higher-order spin-orbit interactions are more than perturbative corrections. They can play a dominant role in shaping the spin texture of non-centrosymmetric materials. Our results open up new avenues for designing spintronic devices that exploit multi-chiral spin textures beyond the conventional spin-orbit paradigm.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
16 pages, 4 figures
Influence of Built-in Electric Fields on the Optoelectronic and Catalytic Properties of Two-Dimensional Materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
Kai Kong, Qiang Wang, Yixuan Li, Yitong Liang
In the realm of modern materials science and advanced electronics, ferroelectric materials have emerged as a subject of great intrigue and significance, chiefly due to their remarkable property of reversible spontaneous polarization. This unique characteristic is not just an interesting physical phenomenon; it plays a pivotal role in revolutionizing multiple technological applications, especially in the domains of high-density data storage and the pursuit of fast device operation. In the past few decades, there has been a significant increase in the number of investigations and commercial applications proposed for ferroelectric materials. With the continuous miniaturization of electronic devices and the rapid development of two-dimensional (2D) materials, considerable efforts have been made towards exploring ferroelectricity in 2D materials, driven by the potential for revolutionary advancements in energy storage, data processing, and other emerging technologies. This exploration is fueled by the realization that 2D ferroelectric materials could offer unique properties such as high energy density, fast switching speeds, and scalability, which are crucial for the next generation of electronic devices. The out-of-plane (OOP) ferroelectricity exhibited by these 2D materials is generally more advantageous than the in-plane ferroelectricity, primarily because the vertical polarizability aligns more seamlessly with the requirements of most practical technological applications
Materials Science (cond-mat.mtrl-sci)
arXiv admin note: text overlap with arXiv:2306.15921
Enhancing interfacial thermal conductance in Si/Diamond heterostructures by phonon bridge
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
Ershuai Yin, Qiang Li, Wenzhu Luo, Lei Wang
This study investigates the mechanism of enhancing interfacial thermal transport performance in Silicon/Diamond (Si/Diamond) heterostructures using the phonon bridge. A heat transfer model for three-layer heterostructures is developed by combining First-principles calculations with the Monte Carlo method. The temperature distribution, spectral heat conductance, and interfacial thermal conductance are compared for Si/Diamond heterostructures with and without a silicon carbide (SiC) interlayer. The results show that the SiC interlayer effectively bridges low-frequency phonons in Si with mid-to-high-frequency phonons in Diamond, which forms a specific phonon bridge, significantly improving interfacial phonon transport. The influence of SiC interlayer thickness is further studied, revealing a size-dependent phonon bridge enhancement. For thin interlayers, intensified phonon boundary scattering weakens the bridging effect. Conversely, excessively thick interlayers increase the bulk thermal resistance, reducing overall interfacial thermal conductance. Thus, an optimal interlayer thickness exists, identified as 40 nm for SiC. Thirteen candidate interlayer materials, including SiC, AlN, {\alpha}-Si3N4, \b{eta}-Si3N4, and AlxGa1-xN (x ranges from 0.1 to 0.9), are compared at various thicknesses. SiC emerges as the most effective interlayer material, increasing interfacial thermal conductance by 46.6% compared to the bilayer heterostructure. AlN ranks second, improving thermal conductance by 21.9%. These findings provide essential insights into the phonon bridge mechanism at heterogeneous interface thermal transport and offer valuable theoretical guidance for designing heterostructures with enhanced thermal transport performance.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
18 pages, 8 figures
Observation of spin-conserving two-spinon continuum in the $S$=1/2 antiferromagnetic chain system Sr$_2$CuO$_3$ using Cu $K$-edge resonant inelastic x-ray scattering
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-31 20:00 EDT
Kenji Ishii, Kenji Tsutsui, Takayuki Kawamata, Yoji Koike
We report a Cu $ K$ -edge resonant inelastic x-ray scattering (RIXS) study of spin excitations in the $ S$ =1/2 antiferromagnetic chain system Sr$ _2$ CuO$ _3$ . The spectral weight observed below the charge-transfer gap appears in two-spinon continuum, indicating the fractionalization of a spin-conserving ($ \Delta S = 0$ ) magnetic excitation into two-spinon states. The intensity of these excitations reaches a maximum near the midpoint between the center and the boundary of the Brillouin zone, and decreases toward the zone boundary; this behavior contrasts with that of the spin-flip ($ \Delta S = 1$ ) excitations typically observed via inelastic neutron scattering or Cu $ L_3$ -edge RIXS. The momentum dependence of the intensity is described by the spin-exchange dynamical structure factor. A phenomenological analysis of the symmetry between the polarization and the $ d$ orbital explains the resonance condition for the two-spinon excitations.
Strongly Correlated Electrons (cond-mat.str-el)
8 pages, 5 figures
Dynamical signatures and control of time-reversal breaking in twisted nodal superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-31 20:00 EDT
Jefferson Tang, Pavel A. Volkov
Recent observations of time-reversal breaking superconductivity at twisted cuprate interfaces motivate the development of new approaches to better characterize this emergent phenomenon. Here we study the dynamical properties of the order parameters at the twisted unconventional superconductor interfaces. We reveal the emergence of a soft collective mode (Josephson plasmon) at the time-reversal breaking transition, which can be tuned by temperature, twist angle or magnetic field. Furthermore, nonlinear dynamical responses are shown to contain direct signatures of both the transition and the broken symmetry itself. In particular, we show that second harmonic generation is a necessary and sufficient condition for the symmetry breaking. We discuss the signatures of our predictions in AC current-driven experiments and show that strong nonlinear driving allows to induce dynamical phase transitions between phases with and without spontaneous symmetry breaking.
Superconductivity (cond-mat.supr-con)
Vortex Pinning in Niobium covered by a thin polycrystalline Gold
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-31 20:00 EDT
Wenbin Li, Ivan Villani, Ylea Vlamidis, Matteo Carrega, Letizia Ferbel, Leonardo Sabattini, Antonio Rossi, Wen Si, Stefano Veronesi, Camilla Coletti, Sergio Pezzini, Masahiro Haze, Yukio Hasegawa, Stefan Heun
Owing to its superconducting properties, Niobium (Nb) is an excellent candidate material for superconducting electronics and applications in quantum technology. Here we perform scanning tunneling microscopy and spectroscopy experiments on Nb films covered by a thin gold (Au) film. We investigate the minigap structure of the proximitized region and provide evidence for a highly transparent interface between Nb and Au, beneficial for device applications. Imaging of Abrikosov vortices in presence of a perpendicular magnetic field is reported. The data show vortex pinning by the granular structure of the polycrystalline Au film. Our results show robust and homogeneous superconducting properties of thin Nb film in the presence of a gold capping layer. The Au film not only protects the Nb from surface oxidation but also preserves its excellent superconducting properties.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph), Quantum Physics (quant-ph)
Electronic Structure of Bimetallic CoRu Catalysts Modulates SWCNT Nucleation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
Alister J. Page, Dan Villamanca, Placidus B. Amama, Ben McLean
Nucleation of single-walled carbon nanotubes (SWCNTs) via chemical vapour deposition of methane on CoRu bimetallic nanoparticles is simulated using quantum chemical molecular dynamics. By varying the Ru loading in the catalyst, we show that Ru decreases catalytic efficiency; C-H bond activation is impeded, key reactive intermediate species become longer-lived on the catalyst surface, and longer carbon chains are stabilised through the earliest stages of SWCNT nucleation. Analysis of the CoRu nanoparticle structure during the CVD process shows that this influence of Ru is indirect, with the catalyst adopting Ru-Co core-shell or segregated structures throughout nucleation, and Co exclusively driving the catalytic decomposition of the methane precursor. We show that the influence of Ru occurs via the electronic structure of the catalyst itself, by lowering the Fermi level of the catalyst due to lower energy 4d/5s states, in a manner consistent with d-band theory.
Materials Science (cond-mat.mtrl-sci)
Antiferromagnetic Order and Magnetic Frustration in the Honeycomb Heavy-Fermion System Ce(Pt${1-x}$Pd${x}$)$_6$Al$_3$: $^{27}$Al and $^{195}$Pt NMR Studies
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-31 20:00 EDT
Shunsaku Kitagawa, Fumiya Hori, Kenji Ishida, Ryohei Oishi, Yasuyuki Shimura, Takahiro Onimaru, Toshiro Takabatake
Heavy-fermion systems with magnetic frustration offer a rich platform for investigating the interplay among Kondo screening, magnetic frustration, and quantum criticality. We report comprehensive $ ^{27}$ Al and $ ^{195}$ Pt nuclear magnetic resonance measurements on polycrystalline Ce(Pt$ _{1-x}$ Pd$ {x}$ )$ 6$ Al$ 3$ ($ x = 0$ , 0.1, 0.2, and 0.3). For $ x = 0$ , the Knight shift, linewidth, and nuclear spin-lattice relaxation rate reveal a paramagnetic heavy-fermion ground state persisting down to 0.1~K, characterized by a coherence temperature $ T{\mathrm{coh}} \simeq 15$ ~K. Substituting Pd induces antiferromagnetic order at $ T{\mathrm{N}} \simeq 3.5$ ~K, while suppressing $ T{\mathrm{coh}}$ . Comparison between $ x = 0.1$ and $ x = 0.3$ reveals a crossover from itinerant spin-density-wave antiferromagnetism to more localized-moment antiferromagnetism, indicating a shift toward the localized side of the Doniach phase diagram. These findings establish Ce(Pt$ _{1-x}$ Pd$ _{x}$ )$ _6$ Al$ _3$ as a tunable platform to explore the competition between Kondo screening and magnetic frustration.
Strongly Correlated Electrons (cond-mat.str-el)
7 pages, 6 figures
J. Phys. Soc. Jpn. 94, 094702 (2025)
A Microfluidic Platform for Actin-Based Membrane Remodeling Reveals the Stabilizing Role of Branched Actin Networks on Lipid Microdomains
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-31 20:00 EDT
Lixin Huang, Rogério Lopes dos Santos (LAMBE - UMR 8587), Sid Labdi (UEVE, LAMBE - UMR 8587, IUT D’EVRY), Guillaume Lamour (LAMBE - UMR 8587, UEVE), Olek Maciejak (SABNP, LAMBE - UMR 8587), Michel Malo (LAMBE - UMR 8587), John Manzi, Martin Lenz (LPTMS, PMMH), Jacques Fattaccioli (IPGG, PASTEUR), Clément Campillo (LAMBE - UMR 8587)
Cell shape changes, essential for processes such as motility or division, are controlled by the actomyosin cortex that actively remodels biological membranes. Their mechanisms can be deciphered in___vitro using biomimetic reconstituted systems, such as giant unilamellar vesicles (GUVs) with controlled lipid composition coupled to reconstituted actin networks. These assays allow mimicking cell shape changes in controlled biochemical and biophysical environments. However, studying the dynamics of these shape changes on statistically significant populations of GUVs with the possibility to sequentially modify the protein composition of the assay is a major experimental challenge. To address these issues, a microfluidic approach is used to immobilize several dozens of isolated GUVs and monitor membrane and actin network evolution. The loading of the chamber with GUVs and actin is first characterized. Then, the actin-induced remodeling of populations of homogeneous and phase-separated GUVs is monitored and shows that actin networks prevent the coalescence of lipid microdomains and that, in return, the number of domains affects the actin network structure. This microfluidic-based experimental strategy, thus, allows for studying actin-induced membrane deformation in___vitro and can be adapted to other studies on membrane remodeling processes.
Soft Condensed Matter (cond-mat.soft)
Small Science, 2025, pp.2500210
aLLoyM: A large language model for alloy phase diagram prediction
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
Yuna Oikawa, Guillaume Deffrennes, Taichi Abe, Ryo Tamura, Koji Tsuda
Large Language Models (LLMs) are general-purpose tools with wide-ranging applications, including in materials science. In this work, we introduce aLLoyM, a fine-tuned LLM specifically trained on alloy compositions, temperatures, and their corresponding phase information. To develop aLLoyM, we curated question-and-answer (Q&A) pairs for binary and ternary phase diagrams using the open-source Computational Phase Diagram Database (CPDDB) and assessments based on CALPHAD (CALculation of PHAse Diagrams). We fine-tuned Mistral, an open-source pre-trained LLM, for two distinct Q&A formats: multiple-choice and short-answer. Benchmark evaluations demonstrate that fine-tuning substantially enhances performance on multiple-choice phase diagram questions. Moreover, the short-answer model of aLLoyM exhibits the ability to generate novel phase diagrams from its components alone, underscoring its potential to accelerate the discovery of previously unexplored materials systems. To promote further research and adoption, we have publicly released the short-answer fine-tuned version of aLLoyM, along with the complete benchmarking Q&A dataset, on Hugging Face.
Materials Science (cond-mat.mtrl-sci), Artificial Intelligence (cs.AI)
24 pages, 6 figures
Lattice tuning of charge and spin transport in $β_{12}$-borophene nanoribbons
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-31 20:00 EDT
Masoumeh Davoudiniya, Jonas Fransson, Biplab Sanyal
Lattice vibrations critically shape charge and spin transport by governing carrier scattering, spin-charge interactions and spectral redistribution in nanostructures. In this study, we investigate how electron-phonon coupling (EPC) and structural configurations intertwine in magnetic and nonmagnetic $ \beta_{12}$ -borophene nanoribbons (BNRs). Using a tight-binding framework with site-dependent hopping parameters extracted from ab initio calculations and incorporating phonons within the Holstein model, we compute phonon-renormalized Green’s functions and transport currents via the Landauer-Büttiker formalism. We find that spin-dependent EPC enhances spin-dependent current in magnetic zigzag (ZZ) nanoribbons, driven by phonon-induced inelastic scattering and spin-selective band renormalization. Additionally, we observe an enhancement of charge transport current in the nonmagnetic configurations of $ \beta_{12}$ -BNRs. Structural variations further induce anisotropic EPC effects, significantly reshaping charge and spin transport. These insights establish EPC as a powerful design lever for optimizing borophene-based logic devices through tailored edge engineering.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Computational Physics (physics.comp-ph), Quantum Physics (quant-ph)
16 pages, 9 figures
Quantum siphoning of finely spaced interlayer excitons in reconstructed MoSe2/WSe2 heterostructures
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-31 20:00 EDT
Mainak Mondal, Kenji Watanabe, Takashi Taniguchi, Gaurav Chaudhary, Akshay Singh
Atomic reconstruction in twisted transition metal dichalcogenide heterostructures leads to mesoscopic domains with uniform atomic registry, profoundly altering the local potential landscape. While interlayer excitons in these domains exhibit strong many-body interactions, extent and impact of quantum confinement on their dynamics remains unclear. Here, we reveal that quantum confinement persists in these flat, reconstructed regions. Time-resolved photoluminescence spectroscopy uncovers multiple, finely-spaced interlayer exciton states (~ 1 meV separation), and correlated emission lifetimes spanning sub-nanosecond to over 100 nanoseconds across a 10 meV energy window. Cascade-like transitions confirm that these states originate from a single potential well, further supported by calculations. Remarkably, at high excitation rates, we observe transient suppression of emission followed by gradual recovery, a process we term “quantum siphoning”. Our results demonstrate that quantum confinement and competing nonlinear dynamics persist beyond the ideal moire paradigm, potentially enabling applications in quantum sensing and modifying exciton dynamics via strain engineering.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics)
33 pages, 4 maintext and 10 supplementary information figures
Random matrix theory of charge distribution in disordered quantum impurity models
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-31 20:00 EDT
Maxime Debertolis, Serge Florens
We introduce a bare-bone random matrix quantum impurity model, by hybridizing a localized spinless electronic level with a bath of random fermions in the Gaussian Orthogonal Ensemble (GOE). While stripped out of correlations effects, this model reproduces some salient features of the impurity charge distribution obtained in previous works on interacting disordered impurity models. Computing by numerical sampling the impurity charge distribution in our model, we find a crossover from a Gaussian distribution (centered on half a charge unit) at large hybridization, to a bimodal distribution (centered both on zero and full occupations of the charge) at small hybridization. In the bimodal regime, a universal $ (-3/2)$ power-law is also observed. All these findings are very well accounted for by an analytic surmise computed with a single random electron level in the bath. We also derive an exact functional integral for the general probability distribution function of eigenvalues and eigenstates, that formally captures the statistical behavior of our model for any number $ N$ of fermionic orbitals in the bath. In the Gaussian regime and in the limit $ N\to\infty$ , we are able to solve exactly the random matrix theory (RMT) for the charge distribution, obtaining perfect agreement with the numerics. Our results could be tested experimentally in mesoscopic devices, for instance by coupling a small quantum dot to a chaotic electronic reservoir, and using a quantum point contact as local charge sensor for the quantum dot occupation.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Disordered Systems and Neural Networks (cond-mat.dis-nn), Strongly Correlated Electrons (cond-mat.str-el)
16 pages, 5 figures
The multiconfigurational ground state of a diradicaloid characterized at the atomic scale
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-31 20:00 EDT
Elia Turco, Lara Tejerina, Gonçalo Catarina, Andres Ortega-Guerrero, Nils Krane, Leo Gross, Michal Juríček, Shantanu Mishra
We report the tip-induced generation and scanning probe characterization of a singlet diradicaloid, consisting of two phenalenyl units connected by an sp-hybridized C$ _{4}$ chain, on an ultrathin insulating NaCl surface. The bond-order contrast along the C$ _{4}$ chain measured by atomic force microscopy and mapping of charge-state transitions by scanning tunneling microscopy, in conjunction with multiconfigurational calculations, reveal that the molecule exhibits a many-body ground state. Our study experimentally demonstrates the manifestation of strong electronic correlations in the geometric and electronic structures of a single molecule.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el), Chemical Physics (physics.chem-ph)
Main text: 17 pages and 3 figures. Supporting Information: 36 pages and 21 figures
Broadband ferromagnetic resonance in Ni-Mn-Ga single crystal
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
Luděk Kraus, Denys Musiienko, Martin Kempa, Jaroslav Čapek
We present a broadband ferromagnetic resonance study in single crystalline Ni$ _{50}$ Mn$ _{28.1}$ Ga$ _{21.9}$ in the temperature range from room temperature to 120 °C in which the transformation from martensite to austenite phase takes place. Our measurements demonstrate that a large change (an order of magnitude) in the magnetocrystalline anisotropy at the martensitic phase transformation results in a sharp change of the resonance magnetic field. In a single variant martensite phase, the resonance fields satisfy the Kittel’s resonance condition for a thin film with the gyromagnetic factor g = 2.0. With the magnetic field parallel to the easy c-axis of the single variant martensite, the resonance is observed only for frequencies larger than 22 GHz. For the multivariant martensite case, the magnetic coupling between the twin variants can be taken into account for the satisfactory Kittel’s fit. We observe a weak magnetocrystalline anisotropy in the austenite phase, just above the reverse martensite transformation, comparable to the previous reports based on different magnetic measurements.
Materials Science (cond-mat.mtrl-sci)
Journal of Magnetism and Magnetic Materials 629 (2025) 173330
Configurational density of states of finite classical systems
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-31 20:00 EDT
In this work, using a microcanonical framework, we provide an explicit inversion formula that allows the calculation of the configurational density of states from the total density of states without resorting to the inversion of the Laplace transform. From this formula, several results can be obtained for the thermodynamics of classical systems composed of a few degrees of freedom, while at the same time recovering the well-known behavior in the thermodynamic limit.
Statistical Mechanics (cond-mat.stat-mech)
Configurational density of states of power-law potentials and the virial theorem in steady states
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-31 20:00 EDT
In this brief note, the configurational density of states of a system of particles interacting via power-law pair potentials is computed exactly. The result is consistent with a constant microcanonical heat capacity. The well-known form of the virial theorem for this class of systems is recovered using only the obtained configurational density of states, and shown to be valid beyond the canonical and microcanonical ensembles, in general steady states.
Statistical Mechanics (cond-mat.stat-mech)
Inducing ferromagnetism by structural engineering in a strongly spin-orbit coupled oxide
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
Ji Soo Lim, Carmine Autieri, Merit Spring, Martin Kamp, Amar Fakhredine, Pavel Potapov, Daniel Wolf, Sergii Pylypenko, Axel Lubk, Johannes Schultz, Nicolas Perez, Börge Mehlhorn, Louis Veyrat, Mario Cuoco, Fadi Choueikan, Philippe Ohresser, Bernd Büchner, Giorgio Sangiovanni, Ralph Claessen, Michael Sing
Magnetic materials with strong spin-orbit coupling (SOC) are essential for the advancement of spin-orbitronic devices, as they enable efficient spin-charge conversion, complex magnetic structures, spin-valley physics, topological phases and other exotic phenomena. 5d transition-metal oxides such as SrIrO3 feature large SOC, but usually show paramagnetic behavior due to broad bands and a low density of states at the Fermi level, accompanied by a relatively low Coulomb repulsion. Here, we unveil ferromagnetism in 5d SrIrO3 thin films grown on SrTiO3 (111). Through substrate-induced structural engineering, a zigzag stacking of three-unit-cell thick layers along the [111] direction is achieved, stabilizing a ferromagnetic state at the interfaces. Magnetotransport measurements reveal an anomalous Hall effect below ~30 K and hysteresis in the Hall conductivity below 7 K, indicating ferromagnetic ordering. X-ray magnetic circular dichroism further supports these results. Theoretical analysis suggests that the structural engineering of the IrO6 octahedral network enhances the density of states at the Fermi level and thus stabilizes Stoner ferromagnetism. This work highlights the potential of structurally engineered 5d oxides for spin-orbitronic devices, where efficient control of SOC-induced magnetic phases by electric currents can lead to lower energy consumption and improved performance in next-generation device technologies.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Active spin model for cell assemblies on 1D substrates
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-31 20:00 EDT
Harshal Potdar, Ignacio Pagonabarraga, Sudipto Muhuri
The experimental use of micropatterned quasi-1D substrates has emerged as an useful experimental tool to study the nature of cell-cell interactions and gain insight on collective behaviour of cell colonies. Inspired by these experiments, we propose an active spin model to investigate the emergent properties of the cell assemblies. The lattice gas model incorporates the interplay of self-propulsion, polarity directional switching, intra-cellular attraction, and contact Inhibition Locomotion (CIL). In the absence of vacancies, which corresponds to a confluent cell packing on the substrate, the model reduces to an equilibrium spin model which can be solved exactly. In the presence of vacancies, the clustering is controlled by a dimensionless Peclet Number, Q - the ratio of magnitude of self-propulsion rate and directional switching rate of particles. In the absence of CIL interactions, we invoke a mapping to Katz-Lebowitz-Spohn(KLS) model to determine an exact analytical form of the cluster size distribution in the limit Q << 1. In the limit of Q >> 1, the cluster size distribution exhibits an universal scaling behaviour (in an approximate sense), such that the distribution function can be expressed as a scaled function of Q, particle density and CIL interaction strength. We characterize the phase behaviour of the system in terms of contour plots of average cluster size. The average cluster size exhibit a non-monotonic dependence on CIL interaction strength, attractive interaction strength, and self-propulsion.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech), Biological Physics (physics.bio-ph)
15 pages, 8 figures
Stochastic resonance in disordered charge-density-wave systems
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-31 20:00 EDT
Francesco Valiera, Antonio Picano, Martin Eckstein
Ultrafast disordering observed after photo-excitation challenges the conventional picture of photo-induced transitions where symmetry-breaking takes place along a single collective coordinate. We propose that key spectroscopic signatures of these transient disordered states can be revealed through stochastic resonance, a hallmark of nonlinear stochastic dynamics. Studying the disordered phase of Holstein model we show that, at given frequency, the linear response as a function of temperature has a peak, which indicates enhanced coherent switching between metastable configurations. From this resonance, we extract the intrinsic stochastic transition timescale and energy barrier separating equivalent local minima. This mechanism offers a new perspective to identify and characterize hidden disordered phases in driven many-body systems.
Strongly Correlated Electrons (cond-mat.str-el)
Nonclassical Photon-Assisted Transport in Superconducting Tunnel Junctions
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-31 20:00 EDT
Matthias Hübler, Juan Carlos Cuevas, Wolfgang Belzig
Advances in circuit quantum electrodynamics have enabled the generation of arbitrary nonclassical microwave states and paved the way for addressing novel physics questions. Here, we present a theoretical study of the electrical current in a Josephson tunnel junction interacting with a nonclassical electromagnetic environment. This allows us to generalize classical transport phenomena like photon-assisted tunneling and Shapiro steps to the quantum regime. We predict that the analysis of the supercurrent in such a setup enables the complete reconstruction of quantum states of the electromagnetic environment, something that is not possible with normal tunnel junctions.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Unconventional hybrid-order topological insulators
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-31 20:00 EDT
Wei Jia, Yuping Tian, Huanhuan Yang, Xiangru Kong, Zhi-Hao Huang, Wei-Jiang Gong, Jun-Hong An
Exploring topological matters with exotic quantum states can update the understanding of topological phases and broaden the classification of topological materials. Here, we report a class of unconventional hybrid-order topological insulators (HyOTIs), which simultaneously host various different higher-order topological states in a single $ d$ -dimensional ($ d$ D) system. Such topological states exhibit a unique bulk-boundary correspondence that is different from first-order topological states, higher-order topological states, and the coexistence of both. Remarkably, we develop a generic surface theory to precisely capture them and firstly discover a $ 3$ D unconventional HyOTI protected by inversion symmetry, which renders both second-order (helical) and third-order (corner) topological states in one band gap and exhibits a novel bulk-edge-corner correspondence. By adjusting the parameters of the system, we also observe the nontrivial phase transitions between the inversion-symmetric HyOTI and other conventional phases. We further propose a circuit-based experimental scheme to detect these interesting results. Particularly, we demonstrate that a modified tight-binding model of bismuth can support the unconventional HyOTI, suggesting a possible route for its material realization. This work shall significantly advance the research of hybrid topological states in both theory and experiment.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
7+4 pages, 4+3 figures
Wafer-scale Programmed Assembly of One-atom-thick Crystals
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
Seong-Jun Yang, Ju-Hyun Jung, Eunsook Lee, Edmund Han, Min-Yeong Choi, Daesung Jung, Shinyoung Choi, Jun-Ho Park, Dongseok Oh, Siwoo Noh, Ki-Jeong Kim, Pinshane Y. Huang, Chan-Cuk Hwang, Cheol-Joo Kim
Crystalline films offer various physical properties based on the modulation of their thicknesses and atomic structures. The layer-by-layer assembly of atomically thin crystals provides powerful means to arbitrarily design films at the atomic-level, which are unattainable with existing growth technologies. However, atomically-clean assembly of the materials with high scalability and reproducibility remains challenging. We report programmed crystal assembly (PCA) of graphene and monolayer hexagonal boron nitride (ML hBN), assisted by van der Waals interactions, to form wafer-scale films of pristine interfaces with near-unity yield. The atomic configurations of the films are tailored with layer-resolved compositions and in-plane crystalline orientations. We demonstrate batch-fabricated tunnel device arrays with modulation of the resistance over orders of magnitude by thickness-control of the hBN barrier with single-atom precision, and large-scale, twisted multilayer graphene with programmable electronic band structures and crystal symmetries. Our results constitute an important development in the artificial design of large-scale films.
Materials Science (cond-mat.mtrl-sci)
65 pages, 22 figures
Nano Letters 22 (2022) 1518-1524
Cation Engineering of Cu-Doped CsPbI3: Lead Substitution and Dimensional Reduction for Improved Scintillation Performance
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
David Hadid Sidiq, Somnath Mahato, Tobias Haposan, Michal Makowski, Dominik Kowal, Marcin Eugeniusz Witkowski, Winicjusz Drozdowski, Arramel, Muhammad Danang Birowosuto
To date, inorganic halide perovskite nanocrystals show promising contributions in emerging luminescent materials due to their high tolerance to defects. In particular, the development of cesium lead iodide (CsPbI3) has shown its efficiency for light-harvesting properties. However, further implementation is hindered due to the toxicity of the lead content. Therefore, in this study, we introduced Cu atoms to partially substitute Pb atoms (5% Cu) in the CsPbI3 lattice as a solution to reduce Pb toxicity. A partial lead material is substituted using Cu displays a larger Stokes shift (-67 nm) compared to the pristine, and resulted doped CsPbI3 not undergo the undesired self absorption. An outcome is focused on the champion of fast-component (tau_1) decay time ~0.6 ns. Temperature-dependent radioluminescence outlines an incremental change in the emission intensity is marginally centered at 713 +- 16 nm, which indicates Cu-doped CsPbI3 is not greatly affected by temperature. In addition, we report that the light yield (LY) pristine CsPbI3 after doping is increased to 3.0 +- 0.8 photons/keV. Our work provides physical insights into a tunable scintillation property using transition metal doping toward lead-free based scintillating perovskites.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph), Optics (physics.optics)
22 pages, 6 figures, 3 tables
J. Phys. Chem. C 2024, 128, 47, 20324-20332
Density-functional theory study of the interaction between NV$^{-}$ centers and native defects in diamond
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
Gabriel I. López-Morales, Joanna M. Zajac, Tom Delord, Carlos A. Meriles, Cyrus E. Dreyer
The NV$ ^{-}$ color center in diamond has been demonstrated as a nanoscale sensor for quantum metrology. However, the properties that make it ideal for measuring, e.g., minute electric and magnetic fields also make it sensitive to imperfections in the diamond host. In this work, we quantify the impact of nearby native defects on the many-body states of NV$ ^{-}$ . We combine previous quantum embedding results of strain and electric-field susceptibilities of NV$ ^{-}$ with density-functional theory calculations on native defects. The latter are used to parametrize continuum models in order to extrapolate the effects of native defects up to the micrometer scale. We show that under ideal measuring conditions, the optical properties of NV$ ^{-}$ are measurably affected by the strain caused by single carbon interstitials and vacancies up to 200 nm away; in contrast, the NV$ ^{-}$ is measurably affected by the electric field of such charged (neutral) native defects within a micron (100 nm). Finally, we show how measuring multiple individual NV$ ^{-}$ centers in the vicinity of a native defect can be used to determine the nature of the defect and its charge state.
Materials Science (cond-mat.mtrl-sci)
Thermodynamically driven tilt grain boundaries of monolayer crystals using catalytic liquid alloys
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
Min-Yeong Choi, Chang-Won Choi, Dong-Yeong Kim, Moon-Ho Jo, Yong-Sung Kim, Si-Young Choi, Cheol-Joo Kim
We report a method to precisely control the atomic defects at grain boundaries (GBs) of monolayer MoS2 by vapor-liquid-solid (VLS) growth using sodium molybdate liquid alloys, which serve as growth catalysts to guide the formations of the thermodynamically most stable GB structure. The Mo-rich chemical environment of the alloys results in Mo-polar 5|7 defects with a yield exceeding 95%. The photoluminescence (PL) intensity of VLS-grown polycrystalline MoS2 films markedly exceeds that of the films exhibiting abundant S 5|7 defects, which are kinetically driven by vapor-solid-solid growths. Density functional theory calculations indicate that the enhanced PL intensity is due to the suppression of non-radiative recombination of charged excitons with donor-type defects of adsorbed Na elements on S 5|7 defects. Catalytic liquid alloys can aid in determining a type of atomic defect even in various polycrystalline 2D films, which accordingly provides a technical clue to engineer their properties.
Materials Science (cond-mat.mtrl-sci)
45 pages, 15 figures
Nano Letters 23 (2023) 4516-4523
Decorated Clusters and Geometrical Frustration in Cluster Spin Glass: A Random Graph Approach
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-31 20:00 EDT
S. G. Magalhaes, F. M. Zimmer, R. Erichsen Jr
We develop a theory to investigate how geometrically frustrated clusters that become decorated affect the Cluster Spin Glass phase. The cluster structure is assumed to be a tetrahedron composed of Ising spins with z-anisotropy placed at its vertices that interact antiferromagnetically. We consider the probability $ 1-p_J$ of finding an impurity at a vertex of the tetrahedron that interacts ferromagnetically with the remaining elements inside the tetrahedron. An intercluster disorder is added as a random Gaussian interaction. The order parameters are obtained using the sparse random graph technique, which introduces the connectivity of the network of clusters as a controllable parameter in the theory. We examine changes that occur in the Cluster Spin Glass phase as a function of $ p_J$ and $ c$ , in addition to the antiferromagnetic intracluster couplings $ J_1$ . For intermediate values of $ p_J$ , unexpected results appear. Even when some clusters contain a ferromagnetic impurity, there will still be robust geometric frustration effects in the cluster network. However, the $ p_J$ threshold for this to occur depends on connectivity. Conversely, below this threshold, reduced GF effects favor the reappearance of the CSG phase. Furthermore, the Curie-Weiss temperature $ \Theta_W$ has a gradual change of signal, indicating that the effects of the impurities extend to the paramagnetic phase.
Statistical Mechanics (cond-mat.stat-mech), Disordered Systems and Neural Networks (cond-mat.dis-nn)
26 pages, 10 figures
Transverse Self-Propulsion Enhances the Aggregation of Active Dumbbells
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-31 20:00 EDT
Pasquale Digregorio, Daniela Moretti, Claudio Basilio Caporusso, Lucio Mauro Carenza, Giuseppe Gonnella, Giuseppe Negro, Massimiliano Semeraro, Antonio Suma
We investigate a two-dimensional system of active Brownian dumbbells using molecular dynamics simulations. In this model, each dumbbell is driven by an active force oriented perpendicular to the axis connecting its two constituent beads. We characterize the resulting phase behavior and find that, across all values of activity, the system undergoes phase separation between dilute and dense phases. The dense phase exhibits hexatic order, and for large enough activity, we observe a marked increase in local polarization, with dumbbells predominantly oriented towards the interior of the clusters. Compared to the case of axially self-propelled dumbbells, we find that the binodal region is enlarged towards lower densities at all activities. This shift arises because dumbbells with transverse propulsion can more easily form stable cluster cores, serving as nucleation seeds, and show a highly suppressed escaping rate from the cluster boundary. Finally, we observe that clusters exhibit spontaneous rotation, with the modulus of the angular velocity scaling as $ \omega\sim r_g^{-2}$ , where $ r_g$ is the cluster’s radius of gyration. This contrasts with axially propelled dumbbells, where the scaling follows $ \omega\sim r_g^{-1}$ . We develop a simplified analytical model to rationalize this scaling behavior.
Soft Condensed Matter (cond-mat.soft)
13 pages, 9 figures
Entropy, Volume 27, Number 7, 27 June 2025
Floquet Theory of lattice electrons coupled to an off-resonant cavity
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-31 20:00 EDT
Jules Sueiro, Gian Marcello Andolina, Marco Schirò
We use Floquet theory and the High-Frequency expansion to derive an effective Hamiltonian for electrons coupled to an off resonant cavity mode, either in its vacuum or driven by classical light. For vacuum fields, we show that long-range hopping and cavity-mediated interactions arise as a direct consequence of quantum fluctuations. As an application, this method is applied to the Su-Schrieffer-Heeger (SSH) model. At high light-matter coupling, our results reveal significant deviations from mean-field predictions, with our framework capturing light-matter entanglement through the Floquet micromotion. Furthermore, the cavity-mediated interactions appearing at first order are shown to be crucial to the description of the system at sufficiently strong light-matter coupling for a fixed cavity frequency. Finally, a drive resonant with the cavity is added with the SSH chain displaying dynamical behavior dependent on the cavity parameters.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
16 pages, 8 figures + appendix
Coherence of dipole-forbidden Rydberg excitons in Cu$_2$O measured by polarization- and time-resolved multi-photon spectroscopy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
A. Farenbruch, N. V. Siverin, G. Uca, D. Fröhlich, D. R. Yakovlev, M. Bayer
Quantum applications of solid state systems base upon generation and control of coherent electronic excitations. Prominent examples are exciton states in semiconductors excitable by photons. The high oscillator strength of electric-dipole (ED) allowed exciton states favors their efficient coherent generation, but limits also their lifetime. ED-forbidden exciton states with long recombination times might maintain long-lived coherence, especially in highly-quality crystals with suppressed exciton scattering. Here, we propose a multi-photon technique combining two-photon excitation with difference frequency generation (2PE-DFG) for time-resolved measurements of exciton coherence. The technique utilizes polarization tomography for state-selective control in both the pump and probe processes. Its potential is demonstrated by measuring the coherent dynamics of the ED-forbidden $ S$ and $ D$ excitons in Cu$ _2$ O crystals. The excited states of the Rydberg excitons with principal quantum number $ n=2$ , $ 3$ , and $ 4$ have short dephasing times of a few picoseconds, limited by their relaxation to lower lying states. The dephasing time reaches 3 ns for the $ 1S$ state. In an external magnetic field up to 10 T, the $ 1S$ exciton splits into a triplet so that quantum beats are observed after coherent excitation, for which three distinct regimes are found depending on the chosen polarization tomography scheme. These results establish the 2PE-DFG technique as a powerful tool to assess the coherent dynamics of ED-forbidden excitons.
Materials Science (cond-mat.mtrl-sci)
Phase-engineered Non-degenerate Sliding Ferroelectricity Enables Tunable Photovoltaics in Monolayer Janus In2S2Se
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
Yixuan Li, Qiang Wang, Keying Han, Yitong Liang, Kai Kong, Yan Liang, Thomas Frauenheimc, Xingshuai Lv, Defeng Guo, Bin Wang
Two-dimensional sliding ferroelectrics, with their enhanced efficiencies of charge separation and tunability, constitute promising platforms for next-generation photovoltaic devices. However, recent systems predominantly exhibit dual degenerate polarization states with weak intensity, hindering the optimal manipulations of photovoltaic effects through sliding ferroelectricity. Here, we address this limitation by introducing two strengthened and distinct non-degenerate sliding ferroelectric phases (WZ’ and ZB’) in Janus In2S2Se, which can be achieved by Se-to-S substitution in monolayer In2Se3. First-principles calculations validate the experimental synthesis of this structure and its capability for reversible phase transitions triggered by atomic layer sliding, and a series of superior photovoltaic performances are demonstrated in such unique Janus In2S2Se, accompanied by a detailed analysis of how non-degenerate sliding ferroelectricity modulates distinct photovoltaic characteristics. The WZ’ to ZB’ transition can increase the carrier mobility and moderate the band gap while inducing an indirect-to-direct transition, yielding a marked red-shift and enhancement of the photocurrent peak in the infrared spectrum. Conversely, the WZ’ phase, benefiting from enhanced polarization, delivers superior photoelectric conversion efficiency in the visible light region. This work establishes a phase-engineered framework of how non-degenerate sliding ferroelectricity orchestrates distinct photovoltaic behaviors, and the intrinsic physical correlations may offer novel perspectives for designing and regulating innovative photovoltaic devices.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
Nanoscale Modulation of Flat Bands via Controllable Charge-Density-Waves Defects in 4Hb-TaS2
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-31 20:00 EDT
Wooin Yang, Siavash Karbasizadeh, Hoyeon Jeon, Saban Hus, Arthur P. Baddorf, Sai Mu, Tom Berlijn, Haidong Zhou, Wonhee Ko, An-Ping Li
Electron correlation is a main driver of exotic quantum phases and their interplay. The 4Hb-TaS2 system, possessing intrinsic heterostructure of 1T- and 1H-TaS2 monolayers, offers a unique opportunity to control electron correlation by distorting the atomic lattice or tuning interlayer coupling. Here, we investigated intrinsically deformed charge-density-waves (CDW) in the 1T layer of 4Hb-TaS2 to elucidate and control their effects on flat bands using scanning tunneling microscopy and spectroscopy (STM/S) combined with first-principles calculations. We identified two types of CDW defects: Type 1 has structural distortion and locally suppressed flat bands, while Type 2 features an increased flat band filling factor of intact CDW structure. Density functional theory calculations indicate that a sulfur vacancy in the 1T layer distorts the CDW structure and gives rise to a Type 1, whereas a sulfur vacancy in the 1H layer reduces the interlayer charge transfer and lead to a Type 2. Furthermore, we demonstrated creating and erasing individual CDW defects via STM manipulation. Our findings provide a pathway to not only tune flat bands but also selectively manipulate the interaction between CDW, the atomic lattice, and interlayer coupling in strongly correlated systems with atomic precision.
Strongly Correlated Electrons (cond-mat.str-el)
12 pages, 4 figures
The Effect of Pattern Quality on Measurements of Stress Heterogeneity and Geometrically Necessary Dislocation Density by High-Angular Resolution Electron Backscatter Diffraction
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
Harison S. Wiesman, David Wallis
We examine the effect of pattern quality on the output of high-angular resolution electron backscatter diffraction (HR-EBSD) analyses. Band contrast, as a proxy for pattern quality, was varied by adjusting the number of frames averaged per electron backscatter pattern during data collection. The same region in a deformed sample of the mineral olivine was mapped six times varying the number of frames averaged between 1 and 30 between each map. Each data set was analyzed with HR-EBSD, producing maps of intragranular stress heterogeneity and geometrically necessary dislocation (GND) density. As the number of frames averaged increased, the noise in stress and GND calculations decreased, revealing more substructure in the mapped region. The worst pixels, with low band contrast, are the most improved by increased frame averaging, whereas those with high band contrast are largely unaffected. Additionally, the probability distribution of stresses narrows as high-stress noise is reduced with increased pattern quality, which also affects estimates of dislocation density from statistical analysis of the stress distributions. As regions with high stress and/or high GND density are typically of interest in HR-EBSD maps and are often associated with low band contrast, frame averaging may be used as a tool to improve the quality of these analyses. Most importantly, however, is that comparisons are made between HR-EBSD datasets with similar mean band contrast to ensure that observed differences are microstructural in origin and not an artefact of data collection.
Materials Science (cond-mat.mtrl-sci), Geophysics (physics.geo-ph)
18 Pages, 5 Figures
Doubling the magnetorheological effect of magnetic elastomers
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-31 20:00 EDT
Lukas Fischer, Andreas M. Menzel
One of the most important properties of soft functionalized magnetic composite materials in view of their technological potential is given by the magnetorheological effect. It describes the change in rheological properties such as the shear modulus by application of external magnetic fields. We demonstrate how computational material design can support in approximately doubling the magnitude of this important phenomenon for magnetic elastomers. Key is to work with two perpendicular magnetic field directions. We expect future practical relevance of our concept.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
7 pages, 5 figures + 1 page, 1 figure (supporting information)
Revisiting the Fermion Sign Problem from the Structure of Lee-Yang Zeros. I. The Form of Partition Function for Indistinguishable Particles and Its Zeros at 0~K
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-31 20:00 EDT
Ran-Chen He, Jia-Xi Zeng, Shu Yang, Cong Wang, Qi-Jun Ye, Xin-Zheng Li
To simulate indistinguishable particles, recent studies of path-integral molecular dynamics formulated their partition function $ Z$ as a recurrence relation involving a variable $ \xi$ , with $ \xi=1$ (-1) for bosons (fermions). Inspired by Lee-Yang phase transition theory, we extend $ \xi$ into the complex plane and reformulate $ Z$ as a polynomial in $ \xi$ . By analyzing the distribution of the partition function zeros, we gain insights into the analytical properties of indistinguishable particles, particularly regarding the fermion sign problem (FSP). We found that at 0~K, the partition function zeros for $ N$ -particles are located at $ \xi=-1$ , $ -1/2$ , $ -1/3$ , $ \cdots$ , $ -1/(N-1)$ . This distribution disrupts the analytic continuation of thermodynamic quantities, expressed as functions of $ \xi$ and typically performed along $ \xi=1\to-1$ , whenever the paths intersect these zeros. Moreover, we highlight the zero at $ \xi = -1$ , which induces an extra term in the free energy of the fermionic systems compared to ones at other $ \xi=e^{i\theta}$ values. If a path connects this zero to a bosonic system with identical potential energies, it brings a transition resembling a phase transition. These findings provide a fresh perspective on the successes and challenges of emerging FSP studies based on analytic continuation techniques.
Statistical Mechanics (cond-mat.stat-mech)
11 pages, 3 figures
Geometrical entanglement and alignment regulate self-organization in active ring polymer suspensions
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-31 20:00 EDT
Juan Pablo Miranda, Emanuele Locatelli, Cristian Micheletti, Demian Levis, Chantal Valeriani
We study the emerging self-organization in active ring suspensions, focusing on how the rings’ orientational order and geometric entanglement vary with density and spatial confinement. To quantify entanglement, we introduce the wrapping number, a pairwise measure of ring interpenetration, while orientational order is characterized by the alignment of the normal vectors to the rings’ osculating planes. Both wrapping number and alignment distinguish active from passive systems, and their combination aptly identifies the self-organized states that emerge with the onset of activity. Mutual-information analysis reveals a significant correlation between alignment and wrapping number across all considered active conditions. However, self-organization displays a non-monotonic dependence on the activity-induced entanglement. Specifically, moderate wrapping stabilizes contacts of neighboring aligned rings, while excessive entanglement disrupts alignment. We show that this competition arises because increasing entanglement interferes with the planar conformations required to form aligned stacks. Given the simplicity of this microscopic mechanism, analogous effects may occur more generally in polymer systems where the degree of entanglement is regulated by out-of-equilibrium effects.
Soft Condensed Matter (cond-mat.soft)
Amorphous Solid Model of Vectorial Hopfield Neural Networks
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-07-31 20:00 EDT
We present a vectorial extension of the Hopfield associative memory model inspired by the theory of amorphous solids, where binary neural states are replaced by unit vectors $ \mathbf{s}_i \in \mathbb{R}^3$ on the sphere $ S^2$ . The generalized Hebbian learning rule creates a block-structured weight matrix through outer products of stored pattern vectors, analogous to the Hessian matrix structure in amorphous solids. We demonstrate that this model exhibits quantifiable structural properties characteristic of disordered materials: energy landscapes with deep minima for stored patterns versus random configurations (energy gaps $ \sim 7$ units), strongly anisotropic correlations encoded in the weight matrix (anisotropy ratios $ \sim 10^2$ ), and order-disorder transitions controlled by the pattern density $ \gamma = P/(N \cdot d)$ . The enhanced memory capacity ($ \gamma_c \approx 0.55$ for a fully-connected network) compared to binary networks ($ \gamma_c \approx 0.138$ ) and the emergence of orientational correlations establish connections between associative memory mechanisms and amorphous solid physics, particularly in systems with continuous orientational degrees of freedom. We also unveil the scaling with the coordination number $ Z$ of the memory capacity: $ \gamma_c \sim (Z-6)$ from the isostatic point $ Z_c =6$ of the 3D elastic network, which closely mirrors the scaling of the shear modulus $ G \sim (Z-6)$ in 3D central-force spring networks.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech), Machine Learning (cs.LG), Neural and Evolutionary Computing (cs.NE)
Enhanced Biaxial Compressive Strain Tuning of 2D semiconductors via Hot Dry Transfer on Polymer Substrates
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
Alvaro Cortes-Flores, Eudomar Henríquez-Guerra, Lisa Almonte, Hao Li, Andres Castellanos-Gomez, M. Reyes Calvo
Strain engineering is an effective tool for tailoring the properties of two-dimensional (2D) materials, especially for tuning quantum phenomena. Among the limited methods available for strain engineering under cryogenic conditions, thermal mismatch with polymeric substrates provides a simple and affordable strategy to induce biaxial compressive strain upon cooling. In this work, we demonstrate the transfer of unprecedentedly large levels of uniform biaxial compressive strain to single-layer WS$ _2$ by employing a pre-straining approach prior to cryogenic cooling. Using a hot-dry-transfer method, single-layer WS$ _2$ samples were deposited onto thermally expanded polymeric substrates at 100 $ ^\circ$ C. As the substrate cools to room temperature, it contracts, inducing biaxial compressive strain (up to ~0.5%) in the WS$ _2$ layer. This pre-strain results in a measurable blueshift in excitonic energies compared to samples transferred at room temperature, which serve as control (not pre-strained) samples. Subsequent cooling of the pre-strained samples from room temperature down to 5 K leads to a remarkable total blueshift of ~200 meV in the exciton energies of single-layer WS$ _2$ . This energy shift surpasses previously reported values, indicating superior levels of biaxial compressive strain induced by the accumulated substrate contraction of ~1.7%. Moreover, our findings reveal a pronounced temperature dependence in strain transfer efficiency, with gauge factors approaching theoretical limits for ideal strain transfer at 5 K. We attribute this enhanced efficiency to the increased Young’s modulus of the polymeric substrate at cryogenic temperatures.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
High Entropy Engineering of Magnetic Kagome Lattice (Gd,Tb,Dy,Ho,Er)Mn6Sn6
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
Wenhao Liu, Nikhil Uday Dhale, Youzhe Chen, Pramanand Joshi, Zixin Zhai, Xiqu Wang, Ping Liu, Robert J. Birgeneau, Boris Maiorov, Christopher A. Mizzi, Bing Lv
The magnetic kagome lattice compound RMn6Sn6 (R=rare earth) is an emerging platform to exploit the interplay between magnetism and topological electronic states where a variety of exciting findings such as flat bands, Dirac points as well as the dramatic dependence of magnetic order on the rare-earth element have been reported. High entropy through rare earth alloying, on the other hand, provides another knob to control over the physical properties in this system. Here, by the marriage of high entropy and the magnetic kagome lattice, we obtain (Gd,Tb,Dy,Ho,Er)Mn6Sn6 single crystals and systematically investigate their magnetic and transport properties. Different from the parent phases, the high entropy 166 material displays multiple novel magnetic transitions induced by temperature and external magnetic fields. Furthermore, linear magnetoresistance persisting up to 20 T has been revealed at 4 K. The intrinsic nontrivial band topology also survives in the high entropy form, as evidenced by the intrinsic anomalous Hall effect. Our results highlight high entropy as a powerful approach for tuning the interplay of charge, spin and lattice degree of freedom in magnetic topological materials.
Materials Science (cond-mat.mtrl-sci)
Dipolar optimal control of quantum states
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-07-31 20:00 EDT
Héctor Briongos-Merino, Felipe Isaule, Bruno Juliá-Díaz, Montserrat Guilleumas
Quantum state control is a fundamental tool for quantum technologies. In this work, we propose and analyze the use of quantum optimal control that exploits the dipolar interaction of ultracold atoms on a lattice ring, focusing on the generation of selected states with entangled circulation. This scheme requires time-dependent control over the orientation of the magnetic field, a technique that is feasible in ultracold atom laboratories. The system’s evolution is driven by just two independent control functions. We describe the symmetry constraints and other requirements of this approach, and numerically test them using the extended Bose-Hubbard model. We find that the proposed control can engineer entangled current states with perfect fidelity across a wide range of systems, and that in the remaining cases, the theoretical upper bounds for fidelity are reached.
Quantum Gases (cond-mat.quant-gas)
Revealing Nanoscale Ni-Oxidation State Variations in Single-Crystal NMC811 via 2D and 3D Spectro-Ptychography
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-31 20:00 EDT
Ralf F. Ziesche, Michael J. Johnson, Ingo Manke, Joshua H. Cruddos, Alice V. Llewellyn, Chun Tan, Rhodri Jervis, Paul R. Shearing, Christoph Rau, Alexander J. E. Rettie, Silvia Cipiccia, Darren Batey
Enabling lithium (Li)-ion batteries with higher energy densities, longer cycle life, and lower costs will underpin the widespread electrification of the transportation and large-scale energy storage industries. Nickel (Ni)-rich layered oxide cathodes, such as LiNi$ _{x}$ Mn$ _{y}$ Co$ _{z}$ O$ _{2}$ (NMC, x > 0.8), have gained popularity due to their high specific capacities and lower cobalt content. However, the standard polycrystalline morphology suffers from accelerated degradation at voltages above 4.2 V versus graphite, due to its increased mechanical and chemical instability. Single-crystal NMC (SC-NMC) has emerged as a promising morphology for suppressing the mechanical instability by preventing intergranular cracking; however, robust methods of understanding its chemical degradation pathways are required. We demonstrate how a high-throughput data collection strategy unlocks the ability to perform 2D and 3D ptychography in minutes, where it currently requires hours, and combine this with X-ray absorption near edge spectroscopy (XANES) to visualise the local Ni oxidation state behaviour in SC-NMC811, with nanometre-scale spatial resolution, and use this as a proxy for state-of-charge. By employing this technique at various stages during lifetime cycling to high voltages (>4.2 V), direct mapping of chemical degradation along the Li channels, identification of nucleation sites, and observation of Ni oxidation state heterogeneities across both electrode and particle scales can be achieved. We further correlate these heterogeneities with the formation and growth of the rocksalt phase and oxygen-induced planar gliding. This methodology will advance the fundamental understanding of how high-Ni layered oxide materials chemically degrade during high-voltage operation, guiding the design of more durable battery materials.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
Complex topologies in phase separated droplets predicted from universal phase diagram
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-31 20:00 EDT
Amit Kumar, Gary H. Karpen, Samuel A. Safran
Phase separation of two phase separating solutes in a common solvent can result in mesoscale (micron-sized) droplets with complex topologies of the domains of each solute within each droplet. Such topologies have been observed in-vitro in systems of chromatin oligomers, biomolecular condensates, and polymeric mixtures. In these systems the solutes phase separate from the solvent into droplets due to the relatively large free energy gain, which includes the energies and entropies of mixing with the solvent. Within each droplet, further phase separation can occur between the two solutes due to an additional free energy difference that promotes their demixing; in some systems, the extent of demixing can be, in some cases, be modulated by an additional component. The minimal free energy topologies are predicted as universal functions of the interfacial tension ratios and fractions of each solute within a droplet. We compare the predictions with several experimental systems to estimate the ranges of interfacial tensions. Experimental aspects that may depend on the kinetics or molecular weight variations in the system are also discussed.
Soft Condensed Matter (cond-mat.soft)
Non-periodic Boundary Conditions for Euler Class and Dynamical Signatures of Obstruction
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-07-31 20:00 EDT
Osama A. Alsaiari, Adrien Bouhon, Robert-Jan Slager, F. Nur Ünal
While the landscape of free-fermion phases has drastically been expanded in the last decades, recently novel multi-gap topological phases were proposed where groups of bands can acquire new invariants such as Euler class. As in conventional single-gap topologies, obstruction plays an inherent role that so far has only been incidentally addressed. We here systematically investigate the nuances of the relation between the non-Bravais lattice configurations and the Brillouin zone boundary conditions (BZBCs) for any number of dimensions. Clarifying the nomenclature, we provide a general periodictization recipe to obtain a gauge with an almost Brillouin-zone-periodic Bloch Hamiltonian both generally and upon imposing a reality condition on Hamiltonians for Euler class. Focusing on three-band $ \mathcal{C}_2$ symmetric Euler systems in two dimensions as a guiding example, we present a procedure to enumerate the possible lattice configurations, and thus the unique BZBCs possibilities. We establish a comprehensive classification for the identified BZBC patterns according to the parity constraints they impose on the Euler invariant, highlighting how it extends to more bands and higher dimensions. Moreover, by building upon previous work utilizing Hopf maps, we illustrate physical consequences of non-trivial BZBCs in the quench dynamics of non-Bravais lattice Euler systems, reflecting the parity of the Euler invariant. We numerically confirm our results and corresponding observable signatures, and discuss possible experimental implementations. Our work presents a general framework to study the role of non-trivial boundary conditions and obstructions on multi-gap topology that can be employed for arbitrary number bands or in higher dimensions.
Quantum Gases (cond-mat.quant-gas), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Atomic Physics (physics.atom-ph), Quantum Physics (quant-ph)
13+13 pages, 5+0 figures
Floquet Spin Splitting and Spin Generation in Antiferromagnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-31 20:00 EDT
Bo Li, Ding-Fu Shao, Alexey A. Kovalev
In antiferromagnetic spintronics, accessing the spin degree of freedom is essential for generating spin currents and manipulating magnetic order, which generally requires lifting spin degeneracy. This is typically achieved through relativistic spin-orbit coupling or non-relativistic spin splitting in altermagnets. Here, we propose an alternative approach: a dynamical spin splitting induced by an optical field in antiferromagnets. By coupling the driven system to a thermal bath, we demonstrate the emergence of steady-state pure spin currents, as well as linear-response longitudinal and transverse spin currents. Crucially, thermal bath engineering allows the generation of a net spin accumulation without relying on spin-orbit coupling. Our results provide a broadly applicable and experimentally tunable route to control spins in antiferromagnets, offering new opportunities for spin generation and manipulation in antiferromagnetic spintronics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
7+15 pages, 5+4 figures