元素插层对过渡金属二硫族化合物1T-TaS2中电荷密度波的调控研究

电荷密度波(Charge-density wave, CDW)是凝聚态物理中一个重要的概念，其物理本质至今仍有待澄清。过渡金属二硫族化合物1T-TaS2表现出丰富的CDW态，是研究CDW的理想体系。研究指出1T-TaS2中CDW在层间方向是按一定模式堆垛而成，这种堆垛显著影响其宏观性质，但堆垛的具体模式尚不清楚，层间耦合与CDW的关系有待研究。对该体系进行元素插层能调控层间距离、载流子浓度、轨道有序等性质，从而调控层间耦合，改变CDW的堆垛方式。本项目将制备不同原子半径、价态、磁性的元素(如碱金属、碱土金属、3d过渡金属等)插层的1T-MxTaS2单晶样品，通过结构表征手段观察插层对CDW超结构的影响，通过电、磁、热等测量手段表征材料的CDW及其相关物性，结合理论计算，对CDW与层间耦合的关系进行研究。本项目研究可以为澄清CDW的本质提供参考，也可以为开发1T-TaS2的应用潜力提供帮助。

Charge-density wave (CDW) is an important concept in the field of condensed matter physics. The physical nature of CDW is still an open question so far. The rich set of CDW states in the layered transition metal dichalcogenide 1T-TaS2 makes it a very good platform to study the nature of CDW. Recently, a vertical stacking of CDW with some unknown order is found to exist in the system, which significantly influences the physical properties of 1T-TaS2. The stacking order of CDW and the role of interlayer coupling still need to be figured out. Element intercalation can change the interlayer distance, carrier density, orbital orders etc. to control the interlayer coupling and stacking mode of CDW in the system. In this project, we plan to investigate CDW in intercalated compound 1T-TaS2. We will intercalate elements with different atomic radius, valence, magnetism, such as alkali metal, alkali earth metal, 3d transition metal, etc, to 1T-TaS2 single crystal. We will investigate the intercalation induced influences on CDW superlattice by performing detailed structural characterizations, and the variations of CDW-related physical properties by electrical transport, heat transport, and magnetism measurements. Density functional theory calculations will be performed to explain the experimental observations and the role of interlayer coupling on CDW. The study of this project can help to figure out the nature of CDW and explore possible applications of the novel material 1T-TaS2.