拓扑表面自旋态量子散射及超导邻近效应的STM/STS理论模拟研究

项目名称： 拓扑表面自旋态量子散射及超导邻近效应的STM/STS理论模拟研究

项目编号： No.91321103

项目类型： 重大研究计划

立项/批准年度： 2014

项目学科： 物理学I

项目作者： 张平

作者单位： 北京应用物理与计算数学研究所

项目金额： 45万元

中文摘要： 本项目拟在结题的培育项目基础上系统开展拓扑表面自旋态量子散射及超导临近效应的扫描隧道谱理论模拟研究。主要包括：发展拓扑绝缘体表面上磁性及非磁性杂质散射的多重量子散射理论，并有效应用于扫描隧道谱的实空间、谱空间、动量空间分析；在此基础上，研究拓扑绝缘体表面的台阶散射、量子栅栏散射、法布里-珀罗共振散射、克莱因隧穿、近藤共振散射等多种量子散射现象，模拟其扫描隧道谱，获得一系列由于拓扑表面态的自旋手性和狄拉克色散关系导致的量子态散射新效应；研究拓扑表面自旋态的超导临近效应，通过扫描隧道谱模拟阐明Bi2Te3/NbSe2体系中拓扑表面态的超导配对作用机制，理解其配对序参量的自旋-轨道特征与对称性质；研究Bi2Te3/NbSe2体系中磁性及非磁性杂质的量子散射性质，模拟其扫描隧道谱，预测该系统中散射产生的准粒子态干涉、量子相变等量子过程的基本规律，从而为实验研究该类体系中的超导临近效应提供理论基础。

中文关键词： 拓扑绝缘体；拓扑超导体；拓扑表面态；量子散射理论；扫描隧道谱

英文摘要： In this project, we will systematically carry out theoretical and computational STM/STS studies of the quantum scattering and superconductive proximity effects for the topological surface spin states. We will develop a quantum multiple scattering theory for the magnetic and nonmagnetic impurities on the topological insulator surface, and apply this theory to perform the STS analysis in the spatial, spectrum, and momentum space. Using this theory, we will study step scattering, quantum corral, Fabry-Pét interference, Klein tunneling, and Kondo resonance on the topological insulator surface. We will simulate the STS spectra of these phenomena, and obtain a series of novel quantum scattering effects brought about by the spin chirality and Dirac nature of the topological surface states. We will study the superconductive proximity of the topological surface spin states. Through STS mimulations, we will clarify the pairing mechanism of the topological surface states in the Bi2Te3/NbSe2 system. We will try to understand the spin-orbital characters and symmetry property of the order parameters in this system. We will carry out theoretical STM/STS studies of magnetic and nonmagnetic scattering in the Bi2Te3/NbSe2 system, and predict its quasiparticle interference and quantum phase transition under impurity scattering.

英文关键词： Topological insulator；topological superconductor；topological surface state；quantum scattering theory；STS