单层薄膜界面超导增强效应

Interfacial superconductor is a new member of superconductor family. The research on the interficial superconductivity enhancement mechanism has became a hot topic in condensed matter physics. Monolayer FeSe thin film has been proved to be the only one material with nontrival interfacial superconductivity enhancement. By now electron phonon coupling was recognized as one of the main reasons that responsible for the Tc enhancement. However, we need more evidences to prove this claim. In this project, we provide two methods in searching the new interfacial superconductivity materials. The first one is growing two dimensional NbSe2 thin films on the surface of SrTiO3, we have observed the strong coupling between the electron of surface NbSe2 and the phonon of the substrate in the formal experiments of the project, and we will continue to study their connection. The second is growing FeSe thin film on the surface of InSb, we have observed the superconductivity enhancement in the metal covered InSb nanowire surfaces. In this project, we will continue working on the possibility of the enhancement of FeSe superconductivity. The two methods mentioned in this project are both based on the very successful preparation work and with high feasibility. If we achieved all the targets in this project, it should provide a huge experimental support to the understanding of the interfacial superconductivity enhancement.

界面超导是超导家族的一个新成员。研究界面超导增加机理也是最近凝聚态物理界的热点问题。单层FeSe薄膜超导是目前唯一一种具有不寻常界面超导增强的材料，声子-电子耦合被认为是其超导增强的主要原因之一，然而要证明这一点需要更多的证据。本项目提供了两条技术路线寻找新的界面超导材料，一种是在SrTiO3表面生长二维材料NbSe2，本项目前期实验中已经观察到了NbSe2的电子与衬底的声子的强耦合效应和超导增强，将继续研究他们的对应关系。另一种是在InSb衬底材料上生长FeSe薄膜，目前已经观察到了InSb纳米线会使表面的金属超导增强，本项目将继续观察其是否也会让FeSe的超导得到增强。本项目的两条路线都基于前期成功的准备工作，可行性较高。如果本项目成功实施，将对解释界面超导增强机理提供非常重要的实验支持。

本项目主要开展薄膜界面超导增强效应的研究，开展了NbSe2/STO, GdTe3/SiC, UTe2/SiO2等薄膜样品的生长。NbSe2/STO观察到了很强的界面耦合现象。GdTe3/SiC在高温区发现了未被报道的新的物相，六重对称的新材料。UTe2薄膜样品致力于研究其薄层下的拓扑超导特性，为未来UTe2在器件中的应用提供物理支撑。在项目研究的过程中，课题组发明了多款拥于自主知识产权的实验仪器，包括小光斑真空紫外激光光源、大角度远场显微镜、真空长焦距高放大倍数显微镜等。这些新设备已经得到了多个高校和研究机构的采购，并得到应用且产生了数百万的产值，在材料的研究方面已经发挥了重要作用，利用新仪器与国内同行合作，在MnBixTey等材料的研究中取得了非常好的数据和结果。同时本项目已经生长了10余种高质量的单晶样品，也提供给了多家国内研究单位开展研究。