项目名称: 拓扑绝缘体Bi2Se3的表面修饰改性及界面相互作用机制的理论研究
项目编号: No.61306114
项目类型: 青年科学基金项目
立项/批准年度: 2014
项目学科: 无线电电子学、电信技术
项目作者: 孙家涛
作者单位: 中国科学院物理研究所
项目金额: 25万元
中文摘要: 利用电子的自旋自由度,拓扑绝缘体是一类可以被用作信息存储、能量转换的材料,其性质依赖于费米面附近受体相拓扑保护的无质量狄拉克费米子电子态。近期研究表明狄拉克电子态在表面原子吸附、界面相互作用情况下会发生变化,从而影响基于拓扑绝缘体的自旋器件的输运性能,对拓扑绝缘体的应用前景提出很大的挑战。本项目拟采用密度泛函理论研究拓扑绝缘体Bi2Se3的表面修饰改性和界面相互作用对其本征电子结构的影响,重点研究Ag和Fe金属原子在Bi2Se3拓扑绝缘体材料表面自组装及扩散机制、有机拓扑绝缘体界面对Bi2Se3拓扑绝缘体能带结构的影响,探索表面修饰及界面相互作用对发生拓扑相变的可能性。研究成果将对理解原子在拓扑绝缘体表面的自组装生长过程,实现对自组装过程的调控,从而制备具有特定功能的自组装纳米体系,利用界面工程构造基于拓扑绝缘体的器件等方面都具有重要意义。
中文关键词: 表面和界面;拓扑量子态;拓扑绝缘体;表面态;狄拉克费米子
英文摘要: Topological Insulator (TI) is a class of materials that can be used for information storage and energy conversion by utilizing the spin degree of freedoms. This is characterized by the massless Dirac fermion electron state in the vicinity of the Fermi level that is protected by the bulk topology. Nevertheless, it is recently shown that this unique linear dispersion will be susceptible to surface adsorption of external atoms, and interface contact. The transport properties of spin electronic devices based on TI will not be immune from this influence, which challenge the future application of TI. By adopting density function theory calculations, we will study how the intrinsic surface state of Bi2Se3 are affected under the surface decoration and interface interactions. Research interest will focus especially on the surface assembly and diffusion mechanism of external atoms on Bi2Se3 TI, the possibility of topological phase transition due to the application of surface decoration and interface interaction. The studies of this project will be helpful to the understanding of the assembly mechanism and growth process of atomic adsorption on TI surface, to the controllable assembly and further fabrication of nanostructures with designed functions based on TI, and to the practical realization of TI based spintronic devic
英文关键词: surface and interface;topological quantum state;topological insulator;surface state;Dirac fermion