第二类Dirac半金属AX2（A=Pd、Pt；X=Se、Te）高压物性研究

高压通过压缩晶格进而调节电子结构，是调控材料量子态和发现新物态、新现象的有效手段。过渡金属二硫族化合物表现出异常丰富的物理现象，包括电荷密度波、超导电性、非平庸拓扑量子态及超大磁电阻效应等，是开展高压下相关研究的理想体系。本项目中，申请人在已有的高压研究基础之上，选取最近发现的第二类Dirac半金属材料AX2（A=Pd、Pt；X=Se、Te）为研究对象，以压力为晶格和电子结构的调控参量，通过电阻、霍尔、同步辐射X射线衍射和拉曼等多种物性测量并结合理论计算，研究AX2拓扑量子态的演化行为，揭示PdTe2超导临界参量的变化规律及其内在机理，探索PtX2可能的超导电性。

High pressure, with its ability to adjust the lattice and electronic structures, is a powerful tool to tune materials quantum states and be used to explore novel phenomena that are not available at ambient pressure. Transition metal dichalcogenides (TMDs) are ideal for conducting these studies due to their rich physics manifested, such as charge density wave, superconductivity, nontrivial topological electronic states and large magnetoresistance. Based on our high-pressure research experience with TMDs, in this project we will focus on the newly-discovered type-II Dirac semimetals, AX2 (A=Pd, Pt; X=Se, Te). We will aim at three targets: (i) the pressure evolution of topological quantum states of AX2; (ii) superconducting behaviors of PdTe2 under high pressure and their physics behind; (iii) possible pressure-induced superconductivity of PtX2, through an array of experimental measurements including high-pressure resistance, Hall effect, synchrotron X-ray diffraction and Raman scattering, coupled with high-pressure theoretical calculations.