拓扑绝缘体Bi2Se3和Bi2Te3薄膜中巨Rashba效应的第一性原理研究

项目名称： 拓扑绝缘体Bi2Se3和Bi2Te3薄膜中巨Rashba效应的第一性原理研究

项目编号： No.11274265

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 数理科学和化学

项目作者： 彭向阳

作者单位： 湘潭大学

项目金额： 78万元

中文摘要： 利用Rashba效应操控电子自旋是自旋电子器件得以应用的关键。但在基于普通半导体的自旋场效应管中，Rashba效应一般很微弱，这给器件的室温运行和小型化带来很大困难。硒化铋和碲化铋是第二代三维强拓扑绝缘体，是目前研究的焦点。最近一系列实验发现，硒化铋吸附了Rb 、CO等原子或分子后，会产生比普通半导体大一到两个数量级的巨Rashba效应，这为自旋电子器件的室温运行和小型化带来巨大希望。但是现在仍有很多重要问题有待研究。本项目将基于第一性原理计算研究硒化铋和碲化铋薄膜的巨Rashba效应，发现不同拓扑相对巨Rashba效应的影响，分析面内势梯度与巨Rashba效应之间的关系。在此基础之上，我们提出在拓扑绝缘体薄膜上吸附Pb或Bi原子以及在薄膜双面吸附不同原子的方案来提高Rashba效应，探索用电场对Rashba效应进行调控的方法，为拓扑绝缘体巨Rashba效应的应用打下基础。

中文关键词： 拓扑绝缘体；Rashba效应；自旋电子学；第一性原理计算；

英文摘要： Manipulation of electron spin by Rashba effect is crucial to the application of spintronic devices. However, spin field effect transistors based on conventional semiconductors generally have rather weak Rashba effect, making it very hard for them to operate at room temperatures and to be miniaturized. Bi2Se3 and Bi2Te3, which are the second generation strong 3D topological insulators, are the focus of the current research. Recently, a series of experiments have revealed that adsorption of atoms or molecules such as Rb or CO can induce giant Rashba effect in Bi2Se3，which is one or two orders larger than that of conventional semiconductors. This brings great promise for room temerature operation and miniaturization of the spintronic devices. However, there are still a lot of fundamental issues to be solved. In this project, we will stuy the giant Rashba effect of the the thin films of Bi2Se3 and Bi2Te3 by using first-principles calculations. We will find in what way the different topological phases can affect the giant Rashba effect and analyze how giant Rashba effect is related to the in-plane potential gradients. Based on these findings, we will propose and investigate two schemes to furhter enhance the Rashba effect, namely, adsorption of Pb or Bi atoms on the film and adsorption of different atoms on the two o

英文关键词： topological insulators；Rashba effect；spintronics；first-principles calculations；