近年来，第二类外尔半金属WTe2具有不饱和巨磁阻效应、量子自旋霍尔效应、拓扑超导和外尔费米弧等新奇物性，使其成为凝聚态和材料学领域的研究热点。WTe2的拓扑物质态主要与其结构中的锯齿状W-W原子链有关，通过调控W原子上最外层5d轨道上的电子数，会改变W原子的配位和成键方式，最终产生新的晶体结构。本项目提出在WTe2层间嵌入不同比例的碘原子来使WTe2产生不同程度的结构相变，通过拓扑化学反应脱出层间的碘原子合成新型亚稳相WTe2晶体。本项目还将进行WTe2Ix和亚稳相WTe2的晶体结构解析及拓扑能带结构计算，系统研究碘原子的插层对WTe2的电子输运特性和拓扑表面态所产生的影响。此外，通过高压测试手段可以增强碘原子层与WTe2层之间的耦合作用，诱导出超导等新奇物性。初步探讨新型插层WTe2Ix和亚稳相WTe2的基本物性与晶体结构、电子能带结构、微结构和维度的关系。

In recent years, the type-II Weyl semimetal WTe2 has become a hot spot in the field of condensed matter and materials science due to its novel properties such as unsaturated giant magnetoresistance, quantum spin Hall effect, topological superconductivity and Weyl Fermi arc. The topological state of WTe2 is mainly related to the zigzag W-W atomic chain. By controlling the number of electrons in the outermost 5d orbital of the tungsten atom, the coordination and bonding forms of the tungsten atoms will be changed, resulting in a new crystal structure. In this project, we first propose to intercalate different proportion of iodine atoms between WTe2 layers to make WTe2 produce different degrees of structural phase transition, and then we will synthesize a new metastable phase WTe2 crystals based on topochemical reaction. The crystal structures and topological band structure of WTe2Ix and metastable WTe2 will be determined and calculated. Systematically, the influence of iodine intercalation on the electronic transport properties and topological surface states of WTe2 are investigated. In addition, the coupling between the iodine atom layer and the WTe2 layer can be enhanced by high-pressure measurements, which can induce superconductivity and other novel properties. Then, the correlations between intrinsic physical properties, crystal structure, electronic band structure, microstructure and dimension are preliminarily discussed.