Nodeless d-wave pairing in monolayer FeSe revealed by intra-unit-cell Josephson interferometry
Auteurs : Runxin Li, Yuchen Huo, Jiong Mei, Ming-Qiang Ren, Miaomiao Wang, Quanxing Wei, Fengyu Yao, Maowen Zheng, Qing Qu, Cui Ding, Hongtao Yuan, Zhuoyu Chen, Wei-Qiang Chen, Kun Jiang, Qi-Kun Xue, Yu-Jie Sun
Résumé scientifique
The Josephson effect provides a direct phase-sensitive probe of superconducting order and has played a central role in identifying unconventional pairing symmetries1-6. Conventional Josephson interferometry, however, extracts phase information through engineered junction geometries and crystallographic orientations, rather than by resolving the internal phase structure of the pair state within a single unit cell. Here, we use a superconducting Nb tip to realize atomic-scale Josephson interferometry in monolayer FeSe/SrTiO3. Despite a fully gapped quasiparticle spectrum, the local Josephson response exhibits a striking intra-unit-cell pattern, with maxima centred on Fe-Fe bonds and robust nodal lines along the Fe-Se directions. We show that these nodal lines arise from destructive interference between Josephson tunnelling amplitudes associated with opposite-sign pairing components. Microscopic calculations reproduce the observed spatial pattern and identify it as a fingerprint of nodeless d-wave pairing. Our results establish intra-unit-cell Josephson interferometry as a local phase-sensitive probe of pairing symmetry in unconventional superconductors.
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Résumé scientifique
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Résumé scientifique
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Résumé scientifique
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Résumé scientifique
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Résumé scientifique
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Résumé scientifique
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Résumé scientifique
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Les travaux antérieurs sur lesquels il s’appuie
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Résumé scientifique
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Résumé scientifique
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