外力应变对Bi2Se3拓扑绝缘体能带调控的第一性原理研究  

Band-structure Enngineering of Topological Insulator Bi_2Se_3 Under Mechanical Strain: a First-principles Study

作　　者：连如乾 吴丽铃 黄雨馨 阮毓荣 黄志高[1] 张健敏[1] LIAN Ru-qian WU Li-ling HUANG Yu-xin RUAN Yu-rong HUANG Zhi-gao ZHANG Jian-min(College of Physics and Energy, Fujian Normal University, Fujian Provincial Key Laboratory of Quantum Manipulation and New Energy Materials, Fuzhou 350117, China)

机构地区：[1]福建师范大学物理与能源学院,福建省量子调控与新能源材料重点实验室,福建福州350117

出　　处：《福建师范大学学报（自然科学版）》2017年第4期21-26,共6页Journal of Fujian Normal University：Natural Science Edition

基　　金：国家自然科学基金资助项目(11404058、61574037);福建省自然科学基金资助项目(2017J06001、2015J05005);福建师范大学大学生创新创业训练计划资助项目(cxxl-2016088)

摘　　要：采用密度泛函理论(DFT)的第一性原理方法,研究了拓扑绝缘体Bi_2Se_3在外力应变作用下的电子结构变化.首先对Bi_2Se_3块体结构在不同外力应变下进行了充分的原子弛豫,得到稳定的构型.主要通过改变初始结构的晶格常数的方法来构建沿层内施加外力应变的模型.接着通过能带、态密度(DOS)等分析手段研究不同外力应变下Bi_2Se_3的电子结构演化.研究结果表明:施加应变会使Bi_2Se_3的体能带发生偏移,偏移的幅度与应变大小相关,在压力应变逐渐加大的过程中Γ点附近的能带上移,并能够观察到M形的反转能带,而在拉应变增大的过程中Γ点附近的能带下移,且没有明显的能带反转现象,这些变化导致了Bi_2Se_3经历从半导体到导体的转变.The electronic structure of topological insulator Bi_2Se_3 under strain wasinverstigated by the first-principles method based on density functional theory（ DFT）. First,it fully optimize the Bi_2Se_3 bulk structure was optimized under different strains to obtain the stable structures. The model of strain applied along the layer is constructed by changing the lattice parameters. Then,it study the evolution of electronic structure in Bi_2Se_3 under different strains was studied by analyzing the band structure and density of states（ DOS）. Our results indicate that strain results in the movement of the band structure with the strain increases. Under the compressive strain,the energy band near the Γ point rises up with an inverted band structure of M shape during the process of pressure strain.While,under the tensile strain,the energy band near the Γ point moves down without obvious band inversion. These effects can make Bi_2Se_3 change from semiconductors to conductors.

关 键 词：拓扑绝缘体 Bi2Se3 能带结构 外力应变 

分 类 号：O469[理学—凝聚态物理]