Superconductivity in atomically thin films has attracted great attention, but the superconducting transition temperature T _c is generally lower than that of the bulk. In this respect, the FeSe films grown on SrTiO₃ (STO) substrate have attracted much attention because the T _c was reported as high as 40–109K when the thickness was decreased to a monolayer (single unit cell, 1 UC). Since the T _c of the bulk is only 8K, this value is much higher and the mechanism of this high-temperature superconductivity has been under intensive study, but has yet to be clarified. In this review, we present our detailed study on this 1UC FeSe/STO system using two different types of scanning probes. By taking great care of the control of the STO surface, we show that the superconductivity is localized at the interface of FeSe and STO.

超导在原子级薄的膜已引起高度重视，但超导转变温度Ť _Ç通常比块状的下部是。在这方面，在 SrTiO ₃ (STO) 衬底上生长的 FeSe 薄膜引起了很多关注，因为当厚度减小到单层（单晶胞，1 UC）时，据报道T _c高达 40-109K。由于Ť _Ç体积只有8K，这个值要高得多，这种高温超导的机理一直在深入研究中，但尚未阐明。在这篇综述中，我们使用两种不同类型的扫描探针对这个 1UC FeSe/STO 系统进行了详细研究。通过非常注意对 STO 表面的控制，我们表明超导性位于 FeSe 和 STO 的界面处。