拓扑绝缘体中的量子杂质态及杂质输运特性研究

项目名称： 拓扑绝缘体中的量子杂质态及杂质输运特性研究

项目编号： No.61474018

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 无线电电子学、电信技术

项目作者： 吕海峰

作者单位： 电子科技大学

项目金额： 70万元

中文摘要： 拓扑绝缘体是最近发现的一种新的量子物态，是目前备受关注的前沿研究领域，在室温自旋电子学和拓扑量子计算等方面都有重要的应用前景。拓扑绝缘体的体态具有绝缘的性质，而其边界态或表面态则是受时间反演对称性保护的金属态。由于体内存在大量缺陷，目前实验上面临的一个难题是制备的拓扑绝缘体材料具有很高的体电导性。本课题的核心是研究低温下体态的量子杂质对拓扑绝缘体材料体态和表面态电子性质的影响，以及由此反映的输运性质。研究体内单杂质所引起的近藤效应和禁带内杂质束缚态形成；研究有限掺杂诱导的绝缘体到金属相变和拓扑量子相变；同时讨论有限掺杂情况下边界态间的临界逾渗行为。此外，最近的实验在掺有磁性杂质的拓扑绝缘体薄膜中观测到量子反常霍尔效应，本课题拟研究这一体系中的缺陷态和量子杂质态。通过研究，希望能帮助理解拓扑绝缘体高电导态的形成原因，探索制备高品质样品的方法和原理，为新型量子器件的设计和应用提供物理模型。

中文关键词： 量子杂质；拓扑绝缘体；量子输运

英文摘要： Topological insulators are new states of quantum matters and get increased attention in recent years, which have a potential application in room temperature spintronics and topological quantum computation. They are characterized by a full insulating gap in the bulk and gapless edge ot surface states which are protected by time-reversal symmetry. However, all the newly discovered topological insulators are highly metallic in their bulk states. Key point of present project is to study the effect of quantum impurity on the bulk state and surface state of topological insulators and related transport properties. It is expected to study the Kondo effect and ingap bound state formation in the presence of an Anderson impurity coupled to the bulk state of topological insulators. For finite doping concentration, we will investigate the phase transition from insulator to metal and the possilble topological phase transition. The percolation behavior of the connection between the edge states at finite doping will also be discussed. Furthermore, quantum anomalous Hall effect has been observed in magnetic impurity doped topological insulator thin film recently. We will study the property of a vacancy and quantum impurity in this system. It is expected to understand the high bulk conductance in the topological insulators and explore the principles of the preparation of highly quality samples. Through the study, it is expected to present theoretical basis in design and application of new devices.

英文关键词： quantum impurity;topological insulator;quantum transport