The mechanism of high-temperature superconductivity in the iron-based superconductors remains an outstanding issue in condensed matter physics. The electronic structure plays an essential role in dictating superconductivity. Recent revelation of distinct electronic structure and high-temperature superconductivity in the single-layer FeSe/SrTiO3 films provides key information on the role of Fermi surface topology and interface in inducing or enhancing superconductivity. Here we report high-resolution angle-resolved photoemission measurements on the electronic structure and superconducting gap of an FeSe-based superconductor, (Li0.84Fe0.16)OHFe0.98Se, with a Tc at 41 K. We find that this single-phase bulk superconductor shows remarkably similar electronic behaviours to that of the superconducting single-layer FeSe/SrTiO3 films in terms of Fermi surface topology, band structure and the gap symmetry. These observations provide new insights in understanding high-temperature superconductivity in the single-layer FeSe/SrTiO3 films and the mechanism of superconductivity in the bulk iron-based superconductors.

中文翻译：

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（Li，Fe）OHFeSe块状超导体和单层FeSe / SrTiO3薄膜中超导的常见电子起源。

铁基超导体中高温超导的机理仍然是凝聚态物理中的一个突出问题。电子结构在决定超导性方面起着至关重要的作用。单层FeSe / SrTiO3薄膜中独特的电子结构和高温超导性的最新发现为费米表面拓扑结构和界面在诱导或增强超导性中的作用提供了关键信息。在这里，我们报告了基于FeSe的超导体（Li0.84Fe0.16）OHFe0.98Se的电子结构和超导间隙的高分辨率角度分辨光发射测量结果，Tc为41 K. 我们发现，这种单相体超导体在费米表面拓扑，能带结构和间隙对称性方面表现出与超导单层FeSe / SrTiO3薄膜明显相似的电子行为。这些发现为了解单层FeSe / SrTiO3薄膜中的高温超导性以及块状铁基超导体中的超导性机理提供了新的见解。