铋基拓扑绝缘体中线性磁阻的机制与调控研究

项目名称： 铋基拓扑绝缘体中线性磁阻的机制与调控研究

项目编号： No.11204337

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 物理学I

项目作者： 高波

作者单位： 中国科学院上海微系统与信息技术研究所

项目金额： 30万元

中文摘要： 铋基拓扑绝缘体作为一类全新的电子材料，在未来的自旋电子学以及量子计算领域有着巨大的应用潜力，近年来在基础与应用研究领域都激起了广泛的兴趣。磁阻研究作为拓扑绝缘体输运研究的重要组成部分，一直以来都是研究人员关注的焦点。近两年来，人们相继在一系列铋基拓扑绝缘体材料中发现了线性磁阻，然而其成因尚不清楚。尽管现有的结果均暗示线性磁阻可以成为强无序条件下材料表面拓扑电子态的指标性输运信号，但是至今尚无明确的证据支持这一点。我们计划采用固相-气相反应,水热法等方法制备高质量的铋基拓扑绝缘体材料，并结合多种电荷输运测量手段，明确线性磁阻与材料表面电子态之间的关联，并研究其背后的物理机制。在此基础上，我们将采用载流子浓度调控，在材料中引入非均匀性（表面纳米颗粒/有机分子修饰，表面图形化）等技术手段来增强磁阻，以此探索铋基拓扑绝缘体在磁阻器件方向上的可能应用。

中文关键词： 拓扑绝缘体；超导体；材料合成；电解质胶体；

英文摘要： Bismuth based topological insulator is a whole new class of electric material. It has stimulated extensive research interest due to its potential applications in spintronics and quantum computation. Magnetoresistance measurements play always an important role in the charge transport research in topological insulators. In the last two years, a phenomenon named linear magnetoresistance (LMR) was found in a wide range of bismuth based topological materials, while its origin is still elusive. Though current results suggest that it may originate from the topological protected surface state (TSS) with the presence of strong disorder, no definitive experimental proof is available yet. We aim to synthesize high quality bismuth based topological insulators using Vapour-Solid reaction and Polyol method. We will combine multiple transport measurement techniques to clarify the link between TSS and LMR, and investigate the physical mechanism behind the LMR in these materials. As the step further, we plan to enhance the magnetoresistance by tuning the carrier density, or through the introduction of inhomogeneity in the material by surface decoration techniques, such as the absorption of magnetic nano-particles/molecules on the surface. Our work may help to develop new magnetoresistive devices based on topological insulators.

英文关键词： topological insulator；superconductor；material synthesis；polymer electrolyte；