最近几年，人们发现在部分高温超导材料中，电荷密度波和超导电性存在竞争、共存等复杂关联性。因此，理解电荷密度波动力学效应及其与超导电性的关联对高温超导机理的深入认识具有重要的帮助。2H-TaS2等层状过渡金属二硫化物具备和铜氧超导体中类似的超导和电荷密度波效应，并且具有结构简单、层数可控等优势，迅速成为研究热点之一。本项目拟通过金刚石对顶砧高压技术，对2H-TaS2的晶体结构进行连续调控，这会改变其费米面结构和电声子耦合，进而增强或抑制其电荷密度波序。同时结合高压电输运技术、拉曼散射光谱技术和超快光泵浦-光探测光谱技术，研究高压低温下材料的电输运、声子振动和超快动力学。在此基础上，分析和理解2H-TaS2材料中电荷密度波、超导态、相干声子等集体激发模式的物理性质，并建立一定理论计算模型分析材料中电声耦合效应影响，进而帮助解决过渡金属二硫化物及类似结构性质材料中的电荷密度波和超导转变形成机制。

Recently, complex competition and coexistence relationships between charge density wave and superconductivity have been found in some high temperature superconductors. Thus, understanding the dynamics of the charge density wave and its correlation with superconductivity is of great help to further explore the high-temperature superconducting mechanism. Layered transition metal dichalcogenides (TMDs) such as 2H-TaS2 always exhibit similar physical properties, especially the charge density wave and superconductivity, to cuprates with high superconducting transition temperatures. Since the TMDs exhibit plenty of advantages, such as the relatively simple structure, the controllable layer number, etc., they gradually become one of the research hotspots. This project intends to continuously regulate the crystal structure of 2H-TaS2 by using the high-pressure technology. Compression of the crystalline structure will change the Fermi surface and the electron-phonon coupling of this material, and then enhance or inhibit the charge density wave order and superconductivity. The electrical transport properties, vibrational properties, and ultrafast dynamics of this material at high pressures and low temperatures are expected to be studied in this project by combining the high-pressure electronic transport technique, Raman spectroscopy, and ultrafast optical pump-probe spectroscopy. On this basis, analyzing and understanding the physical properties of the collective excitations in 2H-TaS2, such as the charge-density-wave, superconductivity, coherent phonon, etc., and establishing a theoretical model to understand the electron-phonon coupling effect in TMDs. This project will provide certain supports for the understanding of the charge density wave and superconducting mechanism in TMDs and those high-temperature superconductors with similar structures.