拓扑绝缘体表面态有限尺寸效应研究

项目名称： 拓扑绝缘体表面态有限尺寸效应研究

项目编号： No.11204058

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 物理学I

项目作者： 李源

作者单位： 杭州电子科技大学

项目金额： 25万元

中文摘要： 三维拓扑绝缘体具有类似于绝缘体的能隙但存在无能隙的表面态，这种新奇量子物态及其性质近年来受到广泛关注。本项目拟在能带理论框架内研究拓扑绝缘体表面态的有限尺寸效应，即拓扑绝缘体薄膜厚度、宽度及外磁场对薄膜上下表面、侧表面能带结构、输运性质的影响。具体研究内容包括：拓扑绝缘体一维波导表面态能隙、电导与波导宽度、外磁场强度之间的定量关系；拓扑绝缘体薄膜厚度、宽度对薄膜上下表面、侧表面能带结构、输运性质的影响，以及该薄膜在外磁场下的能带结构及输运特性；圆柱形纳米线表面态能隙与纳米线半径和长度间的定量关系，建立纳米线表面态低能有效哈密顿量模型，区分其与长方体状薄膜表面态性质的异同点。探索拓扑绝缘体表面态的有限尺寸效应，将展现一些与常规半导体异质结二维电子气不同的新量子现象和效应，并可能为从原理上设计一些功能可调的新型自旋电子学器件提供物理基础。

中文关键词： 拓扑绝缘体；边缘态；磁阻；Klein 隧穿；

英文摘要： Three-dimensional topological insulators are a new class of materials that have a bulk band gap and gapless Dirac surface states.Recently, research on the topological insulators, such as Bi2Se3, has attracted much interest because the robust, nontrivial surface states are topologically protected against back scattering from time-reversal invariant defects and impurities. The goal of this project is to investigate the finite-size effect of surface states in the topologicanl insulators according to the low-energy effective Hamiltonian. We plan to study the effect of the thickness,width of the thin film, and the external magnetic field on the dispersion relation and the transport properties of the top, bottom and side surface states in the topological insulator. The content of the research project includes the effect of the width and the magnetic field on the band gap and the conductance for a waveguide on the surface of the topological insulator; the effect of the thickness, width of the topological insulator thin film, and the external magnetic field on the dispersion relation and the transport properties of the top, bottom and side surface states; the quantitative relation between the band gap and the radius, length of the cylindrical nanowire; developing a low-energy effective Hamitonian to describe the surface

英文关键词： Topological insulator；Edge states；Magnetoresistance；Klein tunneling；