Superconducting state properties of Cu-substituted Fe0.99Te0.66Se0.34 exhibiting superconductivity recovered under hydrostatic pressure

Superconducting state properties of Cu-substituted Fe0.99Te0.66Se0.34 exhibiting superconductivity recovered under hydrostatic pressure | 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 Superconducting state properties of Cu-substituted Fe 0.99 Te 0.66 Se 0.34 exhibiting superconductivity recovered under hydrostatic pressure Jaroslaw Pietosa, Roman Puzniak, Damian Paliwoda, Andrzej Katrusiak, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7534484/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 20 Nov, 2025 Read the published version in Scientific Reports → Version 1 posted 12 You are reading this latest preprint version Abstract Magnetic measurements under hydrostatic pressure ( P ) up to 10 kbar and x-ray diffraction measurements up to 10.7 kbar were performed for a single crystal of Fe 0.975 Cu 0.025 Te 0.66 Se 0.34 , which is non-superconducting at ambient pressure. In this compound, we have found pressureinduced recovery of the superconducting state at T c equal to 13.0 K for P = 10 kbar. We determined the parameters characterizing the superconducting state, including the lower and the upper critical fields, coherence length, and penetration depth, and compared them with those for Fe 0.99 Te 0.66 Se 0.34 . We found that the lower critical field for Fe 0.975 Cu 0.025 Te 0.66 Se 0.34 at 0 K and 10 kbar is comparable to the lower critical field for Fe 0.99 Te 0.66 Se 0.34 at ambient pressure, while the upper critical field is significantly higher than that for Fe 0.99 Te 0.66 Se 0.34 at ambient pressure. The estimated increase in superconducting carrier density and effective mass under pressure can be explained if one assumes that applied pressure leads to an increase in structural disorder in the studied material. At 10 kbar, the zero-field critical current density for Fe 0.975 Cu 0.025 Te 0.66 Se 0.34 is four times larger than that for Fe 0.99 Te 0.66 Se 0.34 at ambient pressure. The x-ray diffraction results indicate that under pressure crystal quality apparently degrades. Comprehensive studies of the impact of pressure on the crystal structure indicate an increasing mosaicity evolution with pressure, suggesting that the pressure-induced superconductivity of Fe 0.975 Cu 0.025 Te 0.66 Se 0.34 originates from inhomogeneities, associated also with the superconductivity in other sulpho-iron selenotellurides and antiPbO-type structures. Obviously, the pressure effect on the crystallographic structure can lead to changes in the electronic structure, which is not excluded. Physical sciences/Materials science Physical sciences/Physics superconductors Fe-Te-Se system single crystal x-ray diffraction thermodynamic properties hydrostatic pressure Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 20 Nov, 2025 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Revision requested 22 Sep, 2025 Reviews received at journal 19 Sep, 2025 Reviews received at journal 19 Sep, 2025 Reviews received at journal 10 Sep, 2025 Reviewers agreed at journal 10 Sep, 2025 Reviewers agreed at journal 09 Sep, 2025 Reviewers agreed at journal 09 Sep, 2025 Reviewers invited by journal 09 Sep, 2025 Editor invited by journal 09 Sep, 2025 Editor assigned by journal 08 Sep, 2025 Submission checks completed at journal 05 Sep, 2025 First submitted to journal 04 Sep, 2025 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. 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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-7534484","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":514990159,"identity":"de9aba7f-6d34-481a-99a0-7bcfe3069548","order_by":0,"name":"Jaroslaw Pietosa","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA5ElEQVRIiWNgGAWjYDACZgglx8Z8AMxgbADiAwS0gBQxGLOxJcC1MODXAlWU2EC0FnN25uMPPvyxS+9j4z34uYDBRnbDAd4DeLVYNrMlNs5sS85tY+NLlp7BkGa84QBfAl4tBod5DJt5G5hz2+R7DKR5GA4nbjjAY0BAC//HZp4/9elsbDzGv3kY/hOjhYexmYftcAJQixnQlgOEtQD9YjhzZttxQ6Bf0qx5DJKNZx4m4Bdz/sMPPnz4Uy0v38Z7+DZPhZ1s3/Hegw/wOgzB5IFymXnwacDQgsoYBaNgFIyCUQAGAGKkR7qCk0KRAAAAAElFTkSuQmCC","orcid":"","institution":"Institute of Physics, Polish Academy of Sciences","correspondingAuthor":true,"prefix":"","firstName":"Jaroslaw","middleName":"","lastName":"Pietosa","suffix":""},{"id":514990162,"identity":"cffdeb24-c588-47c5-8773-aa8029a77b0b","order_by":1,"name":"Roman Puzniak","email":"","orcid":"","institution":"Institute of Physics, Polish Academy of Sciences","correspondingAuthor":false,"prefix":"","firstName":"Roman","middleName":"","lastName":"Puzniak","suffix":""},{"id":514990164,"identity":"beee836a-925a-4552-8582-2eec5cf57d12","order_by":2,"name":"Damian Paliwoda","email":"","orcid":"","institution":"European Spallation Source ERIC","correspondingAuthor":false,"prefix":"","firstName":"Damian","middleName":"","lastName":"Paliwoda","suffix":""},{"id":514990165,"identity":"f2d42786-aa26-4b2b-b31b-7f681c79af82","order_by":3,"name":"Andrzej Katrusiak","email":"","orcid":"","institution":"Adam Mickiewicz University","correspondingAuthor":false,"prefix":"","firstName":"Andrzej","middleName":"","lastName":"Katrusiak","suffix":""},{"id":514990166,"identity":"eb04d735-f8bc-44c8-916b-d1fc15f06d9e","order_by":4,"name":"Dariusz J. Gawryluk","email":"","orcid":"","institution":"Paul Scherrer Institute","correspondingAuthor":false,"prefix":"","firstName":"Dariusz","middleName":"J.","lastName":"Gawryluk","suffix":""},{"id":514990169,"identity":"9788c15a-9b12-4701-81e6-0d9698b1477f","order_by":5,"name":"Andrzej Wisniewski","email":"","orcid":"","institution":"Institute of Physics, Polish Academy of Sciences","correspondingAuthor":false,"prefix":"","firstName":"Andrzej","middleName":"","lastName":"Wisniewski","suffix":""}],"badges":[],"createdAt":"2025-09-04 09:23:34","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7534484/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7534484/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41598-025-24806-x","type":"published","date":"2025-11-20T15:58:55+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":96650966,"identity":"277a374b-8a3c-4a20-aa76-13474329d076","added_by":"auto","created_at":"2025-11-24 16:13:08","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1047228,"visible":true,"origin":"","legend":"","description":"","filename":"PietosaFeCuTeSe065SR.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7534484/v1_covered_4c7d4709-fea8-4bc4-9804-74eea838f114.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eSuperconducting state properties of Cu-substituted Fe\u003csub\u003e0.99\u003c/sub\u003eTe\u003csub\u003e0.66\u003c/sub\u003eSe\u003csub\u003e0.34\u003c/sub\u003e exhibiting superconductivity recovered under hydrostatic pressure\u003c/p\u003e","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"superconductors, Fe-Te-Se system, single crystal x-ray diffraction, thermodynamic properties, hydrostatic pressure","lastPublishedDoi":"10.21203/rs.3.rs-7534484/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7534484/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eMagnetic measurements under hydrostatic pressure (\u003cem\u003eP\u003c/em\u003e) up to 10 kbar and x-ray diffraction measurements up to 10.7 kbar were performed for a single crystal of Fe\u003csub\u003e0.975\u003c/sub\u003eCu\u003csub\u003e0.025\u003c/sub\u003eTe\u003csub\u003e0.66\u003c/sub\u003eSe\u003csub\u003e0.34\u003c/sub\u003e, which is non-superconducting at ambient pressure. In this compound, we have found pressureinduced recovery of the superconducting state at \u003cem\u003eT\u003c/em\u003e\u003csub\u003ec\u003c/sub\u003e equal to 13.0 K for \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;10 kbar. We determined the parameters characterizing the superconducting state, including the lower and the upper critical fields, coherence length, and penetration depth, and compared them with those for Fe\u003csub\u003e0.99\u003c/sub\u003eTe\u003csub\u003e0.66\u003c/sub\u003eSe\u003csub\u003e0.34\u003c/sub\u003e. We found that the lower critical field for Fe\u003csub\u003e0.975\u003c/sub\u003eCu\u003csub\u003e0.025\u003c/sub\u003eTe\u003csub\u003e0.66\u003c/sub\u003eSe\u003csub\u003e0.34\u003c/sub\u003e at 0 K and 10 kbar is comparable to the lower critical field for Fe\u003csub\u003e0.99\u003c/sub\u003eTe\u003csub\u003e0.66\u003c/sub\u003eSe\u003csub\u003e0.34\u003c/sub\u003e at ambient pressure, while the upper critical field is significantly higher than that for Fe\u003csub\u003e0.99\u003c/sub\u003eTe\u003csub\u003e0.66\u003c/sub\u003eSe\u003csub\u003e0.34\u003c/sub\u003e at ambient pressure. The estimated increase in superconducting carrier density and effective mass under pressure can be explained if one assumes that applied pressure leads to an increase in structural disorder in the studied material. At 10 kbar, the zero-field critical current density for Fe\u003csub\u003e0.975\u003c/sub\u003eCu\u003csub\u003e0.025\u003c/sub\u003eTe\u003csub\u003e0.66\u003c/sub\u003eSe\u003csub\u003e0.34\u003c/sub\u003e is four times larger than that for Fe\u003csub\u003e0.99\u003c/sub\u003eTe\u003csub\u003e0.66\u003c/sub\u003eSe\u003csub\u003e0.34\u003c/sub\u003e at ambient pressure. The x-ray diffraction results indicate that under pressure crystal quality apparently degrades. Comprehensive studies of the impact of pressure on the crystal structure indicate an increasing mosaicity evolution with pressure, suggesting that the pressure-induced superconductivity of Fe\u003csub\u003e0.975\u003c/sub\u003eCu\u003csub\u003e0.025\u003c/sub\u003eTe\u003csub\u003e0.66\u003c/sub\u003eSe\u003csub\u003e0.34\u003c/sub\u003e originates from inhomogeneities, associated also with the superconductivity in other sulpho-iron selenotellurides and antiPbO-type structures. Obviously, the pressure effect on the crystallographic structure can lead to changes in the electronic structure, which is not excluded.\u003c/p\u003e","manuscriptTitle":"Superconducting state properties of Cu-substituted Fe0.99Te0.66Se0.34 exhibiting superconductivity recovered under hydrostatic pressure","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-17 13:45:43","doi":"10.21203/rs.3.rs-7534484/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-09-22T10:04:41+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-09-19T13:43:03+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-09-19T08:39:07+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-09-10T09:30:58+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"126430256146352439820812203235402937487","date":"2025-09-10T07:20:09+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"191659308793538290742791318998171446234","date":"2025-09-10T02:38:04+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"71521105866510401257269808774183720835","date":"2025-09-10T02:22:41+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-09-10T02:20:39+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-09-09T14:14:03+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-09-08T09:23:03+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-09-06T01:12:50+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2025-09-04T09:13:02+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"04a88a0d-22fc-4e57-ae47-d94704536f78","owner":[],"postedDate":"September 17th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":54885059,"name":"Physical sciences/Materials science"},{"id":54885060,"name":"Physical sciences/Physics"}],"tags":[],"updatedAt":"2025-11-24T16:10:16+00:00","versionOfRecord":{"articleIdentity":"rs-7534484","link":"https://doi.org/10.1038/s41598-025-24806-x","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2025-11-20 15:58:55","publishedOnDateReadable":"November 20th, 2025"},"versionCreatedAt":"2025-09-17 13:45:43","video":"","vorDoi":"10.1038/s41598-025-24806-x","vorDoiUrl":"https://doi.org/10.1038/s41598-025-24806-x","workflowStages":[]},"version":"v1","identity":"rs-7534484","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7534484","identity":"rs-7534484","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}