铁基超导体杂质散射和磁通中心有序态的研究

In the field of Fe-based superconductivity, determination of electron pairing symmetry is of great significance for understanding of electron pairing mechanism, establishment of theoretical microscopic model, as well as understanding of the physical properties of Fe-based superconductors and exploring new superconducting materials. In this project, we plan to use molecular beam epitaxy (MBE) technique to grow high quality Fe-based superconducting films such as FeSe and KFe2Se2 and investigate controllable doping of magnetic atoms such as Co and Ni and nonmagnetic atoms such as Cu in the films. In-situ STM/STS will be used to investigate impurity scattering and vortex core states as well as their spatial distribution in Fe-based superconducting films. The study can help understand the electron pairing symmetry and pairing mechanism, can also provide some new information for the study of impurity scattering in Fe-based superconductors.

在铁基超导研究领域，判定电子配对的对称性对分析和理解电子配对机制并依此建立微观的理论模型、理解铁基超导材料的物理性能和探索新的超导材料都具有重要的意义。在本项目中，我们拟利用分子束外延技术生长高质量的铁基超导体薄膜（如FeSe和KFe2Se2），并控制薄膜中磁性原子（如Co和Ni）和非磁性原子（如Cu）的掺杂，进而利用原位的低温扫描隧道显微镜/谱观察铁基超导薄膜中单杂质散射态和磁通中心的有序态，探索这些态的空间分布。此项研究一方面可以帮助理解铁基超导体电子配对的对称性和配对机制，另一方面也给铁基超导体杂质散射研究提供了新的思路和实验途径。

探索新的超导材料并理解其电子配对机制一直是高温超导研究领域的重要研究课题。本项目实施四年来，主要针对FeSe超导体的薄膜生长、结构以及在不同衬底上的FeSe薄膜的超导性质和配对机制进行了细致的研究，还开展了Ga/GaN异质结构的超导性质研究，取得了一些重要研究进展。