椭偏法测量拓扑绝缘体的复折射率  

Measuring the complex refractive index of topological insulators based on spectroscopic ellipsometry

作　　者：陆华 李扬武 岳增记 曾为 LU Hua;LI Yang-wu;YUE Zeng-ji;ZENG Wei(School of Physical Science and Technology,Northwestern Polytechnical University,Xi’an 710129,China;School of Physical Science and Technology School of Materials Science and Engineering,Northwestern Polytechnical University,Xi’an 710072,China;Institute for Superconducting&Electronic Materials,University of Wollongong,Wollongong 2500,Australia)

机构地区：[1]西北工业大学物理科学与技术学院,陕西西安710129 [2]西北工业大学材料学院,陕西西安710072 [3]伍伦贡大学超导和电子材料研究所,澳大利亚伍伦贡2500

出　　处：《物理实验》2021年第1期22-26,共5页Physics Experimentation

基　　金：国家自然科学基金项目(No.11974283,11774290,61705186);陕西省自然科学基础研究计划项目(No.2020JM-130)。

摘　　要：采用椭偏法测量了拓扑绝缘体Bi 2Te 3单晶的复折射率.运用经典的德鲁德和托克-洛伦兹模型分别对拓扑绝缘体的表面态和体态进行拟合,获得了其折射率和消光系数,并且分析了色散曲线的变化规律.实验结果表明:Bi 2Te 3拓扑绝缘体的体态具有类半导体特性(含带隙),折射率在近红外波段可达7以上;表面态具有类金属特性,厚度约为2.52 nm.The spectroscopic ellipsometer was used to measure the complex refractive index of topological insulators(e.g.Bi 2Te 3 single crystal).The surface and bulk states of Bi 2Te 3 were fitted with the Drude and the Tauc-Lorentz models.The refractive indices and extinction coefficients of surface and bulk states of Bi 2Te 3 topological insulator were achieved.The properties of the dispersion curves for surface and bulk were analyzed.The results demonstrated that the bulk state possessed semiconductor-like properties with a band gap,whose refractive index could exceed 7 at near-infrared wavelengths.The surface state presented metal-like properties with a thickness of 2.52 nm.

关 键 词：椭偏法 拓扑绝缘体 Bi 2Te 3 复折射率 消光系数 

分 类 号：O482.3[理学—固体物理]