Direct Observation of Nodes and Twofold Symmetry in FeSe Superconductor
Direct Observation of Nodes and Twofold Symmetry in FeSe Superconductor
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FeSe 超导体中节点和双重对称性的直接观察
DOI：
10.1126/science.1202226
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发表时间：
2011-06-17
期刊：
影响因子：
56.9
通讯作者：
Xue, Qi-Kun
中科院分区：
文献类型：
--
作者：
Song, Can-Li;Wang, Yi-Lin;Xue, Qi-Kun
扫描隧道光谱提出了铁基超导体中电子配对的轨道有序机制。我们使用扫描隧道显微镜和光谱学研究了铁基超导体硒化铁 (FeSe) 中的电子配对机制。处于超导状态的化学计量 FeSe 晶体薄膜的隧道电导谱揭示了带节点线的间隙函数的证据。通过对磁涡核、Fe 吸附原子和 Se 空位附近的准粒子激发的直接成像，证明了具有双重对称性的电子配对。在微量硒掺杂样品中观察到的条纹电子纳米结构进一步支持了双重配对对称性。各向异性可以用 FeSe 中电子结构的轨道相关重建来解释。
Scanning tunneling spectroscopy suggests an orbital ordering mechanism for electron pairing in an iron-based superconductor. We investigated the electron-pairing mechanism in an iron-based superconductor, iron selenide (FeSe), using scanning tunneling microscopy and spectroscopy. Tunneling conductance spectra of stoichiometric FeSe crystalline films in their superconducting state revealed evidence for a gap function with nodal lines. Electron pairing with twofold symmetry was demonstrated by direct imaging of quasiparticle excitations in the vicinity of magnetic vortex cores, Fe adatoms, and Se vacancies. The twofold pairing symmetry was further supported by the observation of striped electronic nanostructures in the slightly Se-doped samples. The anisotropy can be explained in terms of the orbital-dependent reconstruction of electronic structure in FeSe.