铁基超导体的扫描隧道显微镜研究进展

铁基高温超导体自2008年发现以来，对其超导电性的研究一直是一个热门的课题.扫描隧道显微镜能够在原子尺度进行表面形貌和隧道谱测量，从微观角度研究电子态密度的信息，是研究超导的重要谱学手段.近年来，在铁基超导电性方面，扫描隧道显微镜实验已经积累了一些有价值的结果，本文进行了总结介绍.铁基超导体是多带多超导能隙的超导体，不同材料的费米面结构有很大的变化.扫描隧道显微镜证明，同时有电子和空穴费米面最佳掺杂的铁基样品超导能隙结构是无节点并带有能隙符号变化的s^±波.而进一步的实验发现在没有空穴费米面的FeSe基超导体中也存在能隙符号的相反，对统一铁基超导体的配对对称性提供了重要实验证据.此外，扫描隧道显微镜在研究铁基超导体的电子向列相、浅能带特性、可能的拓扑特性方面，提供了重要的实验数据.本文对上述相关内容进行了总结，并做了相应分析和讨论.

Studies of scanning tunneling spectroscopy on iron-based superconductors

Since the discovery of iron-based superconductors in 2008, it has been a hot topic to research the pairing mechanism of superconductivity. Scanning tunneling microscopy (STM) can be used to detect the electronic information in nano-scale, hence, it is an important tool to do research on superconductivity. In recent 10 years, many valuable works have been carried out by STM in iron-based superconductors. In this paper, we try to make a brief introduction of the STM works in iron-based superconductors. Since the iron-based superconductors have multiple bands and superconducting gaps, the Fermi surface topology can change significantly among different materials. There are some evidences to prove a nodeless s^±-wave pairing in the optimally-doped iron-based superconductors with both electron and hole pockets by STM experiments. Furthermore, it has been demonstrated that FeSe-based materials with only electron pockets also have a sign-change order parameter, which provides a robust evidence for the unified picture of the electron pairing in iron-based superconductors. Besides, STM experiments provide fruitful information about the novel electronic properties including the electronic nematicity, shallow band effect, and possible topological superconductivity. Finally, we also give perspectives about the STM studies in iron based superconductors.