拓扑绝缘体表面态鲁棒性的同步辐射和第一性原理研究

项目名称： 拓扑绝缘体表面态鲁棒性的同步辐射和第一性原理研究

项目编号： No.11204133

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： 王晓雄

作者单位： 南京理工大学

项目金额： 25万元

中文摘要： 拓扑绝缘体因具有性质奇特的表面态而在自旋电子器件、容错量子计算等领域具有针对性应用。其拓扑序受对称性保护是非常稳定的，但最新的研究显示拓扑表面态的色散、自旋结构等却敏感地依赖于表面条件。 本项目在前期研究基础上利用MBE在超高真空系统中制备Bi2Se3等拓扑绝缘体薄膜并在其表面沉积特定原子或分子为探针、利用同步辐射ARPES结合第一性原理计算研究表面态在各类典型作用下的鲁棒性和性质演变。通过控制实验条件氧化拓扑绝缘体薄膜并利用XRD、ARPES研究薄膜原子结构和电子结构演变；在不同厚度的超薄膜表面沉积碱金属，利用线偏振光和圆偏振光ARPES研究能带结构和表面态自旋结构的变化；在薄膜表面沉积自旋轨道耦合效应显著的金属原子，利用ARPES和第一性原理研究表面SOC作用对表面态的影响。 通过研究可以系统理解拓扑表面态在各种典型作用下的鲁棒性和性质演变，为拓扑绝缘体薄膜器件设计和制作奠定基础。

中文关键词： 拓扑绝缘体；表面态；鲁棒性；第一性原理；角分辨光电子能谱

英文摘要： Topological insulators possess surface states with special properties so they can be employed in spintronic devices and fault-tolerant quantum computation. The topological order is very robust due to the time-reversal symmetry protection; however, the properties of surface states such as dispersion and spin texture are sensitive to the detail conditions of surface. In this project,based on our previous research,we are going to grow topological insulator films in ultrahigh vacuum systems with molecular beam epitaxy and deposit specific molecules or atoms onto the surface as a probe to study the robustness and the evolution of surface states upon some typical actions with synchrotron radiation combined with first-principles calculation. To oxidize the topological insulator films with control and study the evolution of atomic structures and surface electronic structures with XRD and ARPES,respectively; deposit alkali metals onto ultrathin topological insulator films with various thicknesses and study surface band structure and spin texture with linearly polarized and circularly polarized ARPES,respectively; deposit metal atoms with substantial SOC effect onto topological insulator films and explore the effect of surface spin-orbital coupling on the surface state properties. We can systemically understand the ro

英文关键词： Topological insulator；Surface state；Robustness；First-principles；Angle resolved photoemission spectroscopy