Sb、Te掺杂Bi2Se3拓扑绝缘体纳米片的制备及表面态输运性质研究

项目名称： Sb、Te掺杂Bi2Se3拓扑绝缘体纳米片的制备及表面态输运性质研究

项目编号： No.11304092

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 数理科学和化学

项目作者： 周远明

作者单位： 湖北工业大学

项目金额： 30万元

中文摘要： 因有望应用于自旋电子器件和容错量子计算，强拓扑绝缘体Bi2Se3近来引起了人们的极大关注。但是，未掺杂的Bi2Se3中因Se空位的存在总是表现出良好的n型导电性，从而在输运测试中引入很大的体电导背景，给表面态输运性质研究带来极大的困难。针对这一问题，本项目拟采用热蒸发方法制备Sb、Te掺杂的Bi2Se3纳米片，以期望降低体电子浓度，抑制体电导对输运过程的影响。在此基础之上，采用低温磁输运测试手段研究表面态的输运性质。主要研究内容包括：探索体电阻率大、表面电子迁移率高的Sb、Te掺杂Bi2Se3纳米片的制备工艺；通过分析Shubnikov-de Haas振荡，获得表面电子浓度、电子有效质量、量子迁移率，研究栅压对表面态的调控规律；通过拟合反弱局域曲线，有望获得自旋-轨道耦合系数和电子退相干率，从而深入研究该材料中的自旋-轨道耦合机制和电子退相机制。这些结果将为新型量子器件的的研发提供基础。

中文关键词： 拓扑绝缘体；表面态；磁输运；自旋-轨道耦合；电子退相干

英文摘要： The strong topological insulator Bi2Se3 has attracted great interest recently for its potential application in spintronic devices and fault tolerant computations. However, undoped Bi2Se3 is always n type owing to a large amount of Se vacancies. A large background can be induced by bulk electron conduction in transport measurements, and affects the investigation of surface state transport properties seriously. In order to reduce the bulk electron density and suppress the bulk electron conduction, we propose to synthesize Sb- and Te-doped Bi2Se3 nanoplates by means of thermal evaporation. Low-temperature magnetotransport measurements are performed to study the transport properties of surface electrons. The first topic in this project is the preparation of Sb- and Te-doped Bi2Se3 nanoplates with large bulk resistivity and high surface electron mobility. Secondly, physical parameters, including surface electron density, electron effective mass and quantum mobility, will be determined by analyzing Shubnikov-de Haas oscillations, and correspondingly one can study the gate-voltage control of the surface states. Thirdly, by fitting weak anti-localization curve, spin-orbit coupling parameter and electron dephasing rate can be obtained, and then both the spin-orbit coupling mechanism and the electron dephasing mechanism w

英文关键词： Topological Insulator；Surface States；Magnetotransport；Spin-orbit Coupling；Electron Dephasing