最近发现的拓扑绝缘体已经成为凝聚态物理和材料学领域中的研究热点。为实现其在自旋电子学器件和拓扑量子计算等多个方面的应用，找到性能优良的真实宿主材料是首要条件。然而，目前已有的拓扑绝缘体材料还不能满足实际需求。下一个阶段的研究应该重点关注拓扑绝缘体新材料，同时考虑与材料表面相关的实际物理问题。结合当前的研究状况和已有的工作基础，本项目将基于第一性原理计算研究下面几个问题：（1）探索光致拓扑相变的可能性，通过光学手段寻找新型拓扑材料；（2）结合外场调控，在量子阱和异质结中寻找二维拓扑绝缘体；（3）研究拓扑绝缘体表面重构与拓扑表面态之间的内在联系；（4）研究闪锌矿和类闪锌矿结构下的三维强、弱拓扑绝缘体和二维拓扑绝缘体之间的关系。本项目满足当前的研究需求，有望为拓扑绝缘体领域的进一步发展提供材料和理论基础。

The newly discovered topological insulators, as novel states of quantum matter, have become a hot topic in the fields of condensed matter physics and material science. In order to eventually achieve their applications on the spintronics and topological quantum computations, the realistic host materials with excellently physical properties are prerequisite. However, the current materials can not meet these needs. The study of topological insulators in next stage should pay more attention to the host materials and also surface related physical problems. In this proposal, based on the current research progress and our previous works, the following issues will be systematically studied using the first-principles calculation. (1) We will explore the X-ray photoelectron induced topological phase transition and search new topological insulators by using this optical approach. (2) We will search two-dimensional topological insulators in the quantum wells and heterostructures by applying various external fields. (3) We will investigate the interplay between the surface reconstructions and nontrivial surface states of topological insulators. (4) We will study the relationship between the three-dimensional strong (weak) topological insulators and two-dimensional topological insulators with zinc-blende and zinc-blende-like crystal structures. Our proposal with these four issues is close to currently experimental progress and actual demands, and will provide good material and theoretical foundations for further development of topological insulators.