低维Bi-Te基纳米材料的制备及其电输运的尺寸效应研究

项目名称： 低维Bi-Te基纳米材料的制备及其电输运的尺寸效应研究

项目编号： No.11504281

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 余念念

作者单位： 武汉理工大学

项目金额： 24万元

中文摘要： 作为三维强拓扑绝缘体材料，Bi2Te3具有表面无质量的狄拉克费米子，其表面态输运性质的研究不仅具有重要的理论价值且对未来自旋器件的应用意义巨大。将Bi2Te3材料低维化以提高比表面积，从而降低体载流子电导的影响，是研究其表面态物理特性的有效途径。目前，对低维Bi2Te3输运特性的研究主要集中在体态和表面态，缺乏对边缘态的认识。本项目拟采用射频磁控溅射和电子束光刻相结合的方法，制备三维方向均在纳米尺度的Bi2Te3层状纳米结构，通过对Bi2Te3层状纳米结构边缘电子结构的探测，结合第一性原理计算边缘的原子排布构型以及能带结构、态密度和电子局域函数等电特性，构建边缘导电模型，通过精确控制其表面原子和边缘原子的比例，研究其表面输运和边缘输运特性，以及表面态-边缘态耦合对材料电输运性质的影响，建立基于边缘导电的低维Bi2Te3纳米结构电输运机制的理论模型，为基于器件功能的输运特性调控提供理论依据。

中文关键词： 铋碲基硫系化合物；低维；边缘电导；电输运；尺寸效应

英文摘要： As the three dimensional Topological Insulator, Bi2Te3 possesses the massless Dirac fermions in its surface state. The research on the transport properties of the surface state is of great importance not only for the theoretical purpose but also for the promising applications of spintronic devices in the future. Fabrication of the low dimensional material to increase the surface-to-volume ratio, for the purpose of minimizing the influence of the bulk conductance is an effective way to study the physical characteristics of the surface state. Currently, research on the transport properties of the low dimensional Bi2Te3 is mainly focused on the bulk and surface state, few concerns the edge state. In this project, the RF magnetron sputtering is employed and in combination with Electron Beam Lithography for the fabrication of Bi2Te3 layers with the size in the three directions are all confined in nanoscale. The edge conductance model will be established based on the experimental detection of the electrical structure of the edge area in combination with the First Principle Calculation of atomic structure and electrical properties of the edge structure model, such as: band structure, density of states, electron localization function and so on. By accurately controlling the ratio of surface to edge atoms, the electrical transport properties of surface state and edge state, as well as the influence of surface-edge state coupling on the transport properties of the material are intended to be thoroughly studied. Consequently, the theoretical model on the electrical transport properties of low dimensional Bi2Te3 materials based on the edge state conductance are planned to be established, which will provide theoretical supports for the manipulation of transport properties of low dimensional Bi2Te3 in order to realize novel device functions.

英文关键词： Bi-Te based chalcogenides;low dimension;edge conductance;electrical transport; size effect