超导/拓扑绝缘体系统的输运问题

项目名称： 超导/拓扑绝缘体系统的输运问题

项目编号： No.11274129

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 数理科学和化学

项目作者： 高锦华

作者单位： 华中科技大学

项目金额： 70万元

中文摘要： 拓扑绝缘体是当前凝聚态物理的研究热点。超导/拓扑绝缘体系统由于其自身的独特性质最近受到广泛关注。实验上已经成功制备出了超导/拓扑绝缘体结，并测到了超导Josephson流。但是，当前这一系统的超导输运理论都是基于简化表面态模型，只关注了拓扑绝缘体表面态的超导输运，与实验情况差别较大。实验中，拓扑绝缘体体内电子态对输运有不可忽略的贡献。通过调整掺杂或门电压控制，可以调节费米面，进而调整体内和表面载流子的相对比例。本项目计划发展一套能够统一描述拓扑绝缘体体内电子态和表面态超导输运的计算方法。基本思想是从拓扑绝缘体k.p模型哈密顿量出发，用解析和数值的方法求解相关物理问题。然后基于此方法，研究这一系统中几个和实验紧密相关的物理问题。本项目的研究能够帮助我们深入全面的理解超导/拓扑绝缘体系统超导输运的规律和特点，不仅具有基础科学研究价值，还可指导未来量子器件的发展。

中文关键词： 金属表面态；人工两维晶格；平带；多层石墨烯；关联基态

英文摘要： Recently, superconductor/topological insulator (S/TI) junction system has drawn a lot of attention since people hope to realize the long-sought yet elusive Majorana fermion in such system. The S/TI junction has been fabricated in experiment, and the direct evidence for Josephson supercurrent in S/TI/S junction has been observed. However, nearly all the transport theories for S/TI junction nowadays are based on the simplified model of surface state, in which only the transport of surface state has been considered. Experiments indicate that the bulk states in TI will play an important role in the transport and could be adjusted by doping or gate voltage. The purpose of this proposal is to develop a transport theory for S/TI system which could describe the contributions of the surface state and bulk state in an uniform way. The basic idea is to use the entire k.p model Hamiltonian of TI instead of the model Hamiltonian of surface state. We plan to use both analytical and numerical methods to treat this system. Then, with our theory, we want to study several concrete transport problems about the S/TI junctions. We believe that the research of this proposal will offer us a complete physical picture for the transport in S/TI junction. It is not only of fundamental interest, but also of a great benefit to future devi

英文关键词： metal surface state；artificial 2D lattice；flat band；multilayer graphene；correlated ground state