弱拓扑绝缘体材料Bi14Rh3I9的制备与电热输运性能研究

项目名称： 弱拓扑绝缘体材料Bi14Rh3I9的制备与电热输运性能研究

项目编号： No.51502228

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 一般工业技术

项目作者： 魏平

作者单位： 武汉理工大学

项目金额： 21万元

中文摘要： 探索非传统的电热输运现象和开发新型高性能热电材料是促进热电转换技术在余热发电和固态制冷领域大规模应用的重要策略。本项目基于拓扑绝缘体新奇的表面态电子结构和弱拓扑绝缘体独特的层状堆垛结构，提出以层状弱拓扑绝缘体Bi14Rh3I9为研究对象，采用垂直布里奇曼法和物理气相沉积工艺制备Bi14Rh3I9单晶和薄膜，利用同步辐射技术研究弱拓扑绝缘体的体态和表面态电子能带结构和晶格动力学特征；开展电子结构和分子动力学计算研究，结合高温和低温电热输运性能测量结果，研究弱拓扑绝缘体的体态和表面态电子的输运规律，阐明层状弱拓扑绝缘体独特的声子传输行为。在此基础上，建立弱拓扑绝缘体电热输运性能独立调控的方法并优化综合热电性能，以此推动弱拓扑绝缘体在热电材料领域的发展。

中文关键词： 热电材料；弱拓扑绝缘体；电子结构；晶格动力学

英文摘要： Exploring unconventional electrical and thermal transport phenomena and developing novel high-performance thermoelectric materials are important strategies to promote the massive applications of thermoelectric conversion technique in the field of waste-heat power generation and solid-state cooling. This project, on the basis of the nontrivial surface state electronic structure of topological insulators (TIs) and the unique layered stack structure of weak TIs, and by taking the layered weak TI system Bi14Rh3I9 as an example, plans to grow Bi14Rh3I9 single crystals and thin films via vertical Bridgman method and physical vapor deposition technique, and to study the electronic band structures of the bulk and surface states and lattice dynamics features by means of synchrotron radiation techniques. By employing electronic structure and molecular dynamics calculations, combining with low- and high-temperature electrical and thermal properties measurements, to investigate the transport mechanisms lying behind the bulk and surface states electrons and to reveal the unique phonon propagation behavior in this layered weak TI. Based on that, developing ways to manipulate the electrical and thermal properties independently and to optimize the overall thermoelectric performance, with a fundamental aim towards facilitating the development of weak TIs in the field of thermoelectric materials.

英文关键词： Thermoelectric materials;Weak topological insulator;Electronic structure;Lattice dynamics