{"paper":{"title":"Observation of flat-bottom U-shaped energy gap in high-Tc nickelate (La,Pr)3Ni2O7 thin films","license":"http://creativecommons.org/licenses/by/4.0/","headline":"An energy-symmetric flat-bottom U-shaped gap consistent with nodeless superconductivity is observed in high-Tc nickelate thin films at ambient pressure.","cross_cats":["cond-mat.mes-hall","cond-mat.mtrl-sci","cond-mat.str-el"],"primary_cat":"cond-mat.supr-con","authors_text":"Haoran Ji, Jian Wang, Tianheng Wei, Wei Ren, Yanzhao Liu, Zhen Liang, Zheyuan Xie, Ziqiang Wang","submitted_at":"2026-05-15T07:48:59Z","abstract_excerpt":"The discovery of high transition temperature (high-Tc) superconductivity in Ruddlesden-Popper (R-P) bilayer nickelates under high pressure has stimulated extensive work to understand the underlying mechanism and search for superconductors with higher Tc. The recent realization of superconductivity in R-P bilayer nickelate thin films with onset Tc above 40 K at ambient-pressure enables the use of a wide array of powerful experimental tools to investigate the unconventional high-Tc superconductivity in bilayer nickelates. Here, using ultra-low temperature scanning tunneling microscopy/spectrosco"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"The energy-symmetric, flat-bottom U-shaped gap with zero residual density of states, taken together with its dependence on magnetic field and temperature, is consistent with the behavior of a superconducting gap, suggesting a nodeless gap function at ultra-low temperatures.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"That the tunneling spectra measured by STM/S directly represent the intrinsic bulk superconducting density of states of the film without dominant contributions from surface reconstruction, disorder, or non-superconducting phases. This premise enters when the abstract interprets the U-shaped gap and its field/temperature dependence as evidence for superconductivity.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Observation of an energy-symmetric flat-bottom U-shaped gap with zero residual DOS in (La,Pr)3Ni2O7 thin films, showing unconventional temperature evolution and magnetic field suppression consistent with a nodeless superconducting gap.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"An energy-symmetric flat-bottom U-shaped gap consistent with nodeless superconductivity is observed in high-Tc nickelate thin films at ambient pressure.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"3112cc779e24f50fc65e7983394f774e8de871e537f0ae49c22a8f6a595a7267"},"source":{"id":"2605.15703","kind":"arxiv","version":1},"verdict":{"id":"73118550-3400-4e12-bd25-48bec69cb0a2","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-19T19:36:09.718993Z","strongest_claim":"The energy-symmetric, flat-bottom U-shaped gap with zero residual density of states, taken together with its dependence on magnetic field and temperature, is consistent with the behavior of a superconducting gap, suggesting a nodeless gap function at ultra-low temperatures.","one_line_summary":"Observation of an energy-symmetric flat-bottom U-shaped gap with zero residual DOS in (La,Pr)3Ni2O7 thin films, showing unconventional temperature evolution and magnetic field suppression consistent with a nodeless superconducting gap.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"That the tunneling spectra measured by STM/S directly represent the intrinsic bulk superconducting density of states of the film without dominant contributions from surface reconstruction, disorder, or non-superconducting phases. This premise enters when the abstract interprets the U-shaped gap and its field/temperature dependence as evidence for superconductivity.","pith_extraction_headline":"An energy-symmetric flat-bottom U-shaped gap consistent with nodeless superconductivity is observed in high-Tc nickelate thin films at ambient pressure."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2605.15703/integrity.json","findings":[],"available":true,"detectors_run":[{"name":"doi_title_agreement","ran_at":"2026-05-19T20:01:19.219182Z","status":"completed","version":"1.0.0","findings_count":0},{"name":"doi_compliance","ran_at":"2026-05-19T19:41:02.875330Z","status":"completed","version":"1.0.0","findings_count":0},{"name":"ai_meta_artifact","ran_at":"2026-05-19T19:33:27.253782Z","status":"skipped","version":"1.0.0","findings_count":0},{"name":"claim_evidence","ran_at":"2026-05-19T17:21:56.029638Z","status":"completed","version":"1.0.0","findings_count":0}],"snapshot_sha256":"b830c9dd33bf587c6117d50e3bad0e35b153d3a78e5165afe5f7351203099bed"},"references":{"count":61,"sample":[{"doi":"","year":2023,"title":"Sun, H. et al. Signatures of superconductivity near 80 K in a nickelate under high pressure. Nature 621, 493–498 (2023)","work_id":"ca66c0e2-d412-4e65-9e3f-9cc0649d088d","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2024,"title":"Zhang, Y . et al. High-temperature superconductivity with zero resistance and strange-metal behaviour in La3Ni2O7−δ. Nature Physics 20, 1269–1273 (2024)","work_id":"81b986d7-7cea-4e07-b3b1-65c8d2b26934","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2024,"title":"Wang, N. et al. Bulk high-temperature superconductivity in pressurized tetragonal La2PrNi2O7. Nature 634, 579–584 (2024)","work_id":"b334401f-9559-4109-8111-c01fa89f2357","ref_index":3,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2024,"title":"Yang, J. et al. Orbital-dependent electron correlation in double-layer nickelate La3Ni2O7. Nature Communications 15, 4373 (2024)","work_id":"e6475322-df82-4b02-baf3-abcb30bcac83","ref_index":4,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2023,"title":"Luo, Z., Hu, X., Wang, M., Wú, W. & Yao, D.-X. Bilayer Two-Orbital Model of La3Ni2O7 under Pressure. Physical Review Letters 131, 126001 (2023)","work_id":"71281e35-25c9-4dfe-a4cd-9c466e523df2","ref_index":5,"cited_arxiv_id":"","is_internal_anchor":false}],"resolved_work":61,"snapshot_sha256":"6304912d01c1838df703bf4ca605f38e6d0e07c160ee3068a98f3ae1419940be","internal_anchors":1},"formal_canon":{"evidence_count":2,"snapshot_sha256":"da719713963e14daec3317d17e3e4d1e41484808767e72aeedf12814fa89df1c"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}