Direct observation of room-temperature exciton condensation

Direct observation of room-temperature exciton condensation | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Direct observation of room-temperature exciton condensation Fuxing Gu, Jiaxin Yu, Guangyu Dai, Shuai Xing, Weiwei Zhang, Lin Dou, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8407857/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Room-temperature condensation of pure excitons would provide a solid-state analogue of superconducting phase coherence, enabling collective quantum transport under ambient conditions. Yet directly verified phase-coherent pure-exciton condensation at 300 K has remained elusive, owing to a binding–lifetime dilemma—the densities required for degeneracy must still allow thermalisation before recombination. Here we leverage spin-forbidden dark excitons and, using plasmon-enhanced interferometric microscopy, directly image their first-order spatial coherence despite their optical inactivity. Using smooth nanoscale spacing-graded Stark confinement with off-axis injection, we demonstrate a quasi-equilibrium Berezinskii-Kosterlitz-Thouless (BKT)-type condensation of dark excitons in monolayer tungsten diselenide at 300 K and ambient pressure. Above a sharp degeneracy threshold, coherence extends beyond 250 thermal de Broglie wavelengths and exhibits algebraic order with a critical exponent consistent with the universal BKT criterion. This room-temperature phase-coherent exciton condensate establishes an accessible nanophotonic platform for phase-resolved studies of correlated quantum phenomena under ambient conditions. Physical sciences/Physics/Condensed-matter physics/Bose–Einstein condensates Physical sciences/Optics and photonics/Optical physics/Nanophotonics and plasmonics Full Text Additional Declarations There is NO Competing Interest. Supplementary Files Supplementaryinformation.pdf Supplementary information Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8407857","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":574891966,"identity":"3f298526-aa7f-4116-b3a5-ffb43ed26f3f","order_by":0,"name":"Fuxing 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