界面超导硒化铁/钛酸锶异质结的电声相互作用研究

The applicant focuses on utilizing angle-resolved photoemission spectroscopy to characterize the electronic properties of novel materials such as topological insulators and graphene, including electron-phonon interactions, spin-orbit interactions and consequences of broken symmetry environments. There are 22 publications until now, three of which are published as the first author, and one of them is being cited more than 100 times..Iron-based superconductors are the second-highest-temperature superconducting material family known to date after the cuprates, these materials have opened new directions for the research of high-temperature superconductivity (HTS), which have attracted great interests. The electron-phonon interaction should play an important role in the superconducting mechanism. To better understand the superconductivity in HTS, the study of its electron-phonon interaction and phonon modes is highly desirable. Interface superconductivity FeSe/SrTiO3 heterostructure is an ideal system for studying the superconductivity of iron-based superconductors since the structure is simple and the superconducting transition temperature (Tc) is very high. In this project, monolayer FeSe film is proposed to be grown on SrTiO3 by molecular beam epitaxial, and in situ angle-resolved photoemission spectroscopy and Raman spectroscopy will be used to study the surface electronic properties, electron-phonon interaction, and the contributions of phonon modes. The main aim of this project is to reveal how the interface effects influence their superconductivity, and then help build an interface superconductivity structure with higher Tc for further research. The research of this project will be helpful for understanding the mechanism of iron-based superconductors, and then revealing the mystery of high Tc superconductivity by analyzing the difference and similarity with cuprates. This will help the discovery and design of other superconductors with higher Tc.

申请人在新奇材料的角分辨光电子能谱研究方面有丰富的经验，迄今发表SCI论文22篇，其中第一作者文章3篇，单篇最高引用超过100次。.铁基超导体是继铜氧化合物高温超导体后被发现的又一类新型高温超导材料，它的发现为高温超导电性研究开辟了一个全新的研究方向。高温超导的物理机理是当今物理学的研究热点之一。电-声相互作用被认为与库仑作用一样在铁基超导中起重要作用，而界面超导FeSe/SrTiO3结构简单且超导临界温度极高，是一个理想的研究体系。本项目拟采用分子束外延在SrTiO3上制备单层FeSe薄膜，以原位的角分辨光电子能谱和拉曼光谱来研究超导薄膜的表面态、电-声相互作用以及各声子模式在电声子耦合中的贡献，揭示界面对高温超导电性的影响，从而构建更理想的界面超导结构，为后续工作打下基础。本项目的开展有助于对界面超导物理机制的理解，进而揭示高温超导的物理奥妙，为寻找更高转变温度的超导材料提供科学依据。

铁基超导体是继铜氧化合物高温超导体后被发现的又一类新型高温超导材料，它的发现为高温超导电性研究开辟了一个全新的研究方向。高温超导的物理机理是当今物理学的研究热点之一。而界面超导结构简单且超导临界温度极高，是一个理想的研究体系。本项目利用分子束外延方法制备拓扑超导异质结构并利用扫描隧道显微镜和角分辨光电子能谱实验研究其奇异量子态；利用角分辨光电子能谱研究了类铁基超导结构的高温铁磁半导体的电子结构，为进一步从理论上理解高温铁磁半导体的形成机理提供了重要支持；并对SrTiO3的几种表面重构进行了表面态研究，有助于揭示界面对高温超导电性的影响，从而构建更理想的界面超导结构，为后续工作打下基础。项目综合了对界面超导的制备和电子态研究，取得了一系列预期研究成果。