高压下铜基二元金属硫族化合物的结构及物性研究

The Cu-base binary metal chalcogenides are very important materials for their widely applied in catalyze, photovoltaic solar cells, and energy storage materials. The study of their structural phase transitions and electrical transport properties under high pressure are the cutting edge of scientific issue in condensed matter physics. In this project, the pressure-induced structural phase transitions of Cu2X and CunX (1<n<2，X=S, Se, Te) will be studied by high pressure Raman spectroscopy and high pressure X-ray diffraction experiment. Combined with the high pressure Hall effect measurement, carrier concentration, electrical resistivity, and Hall mobility of the samples can be measured and the variations of carrier transport properties can be obtained during the phase transitions. With the help of the electrical experiment, we can also detect the pressure-induced metallization of the sample. We still investigate the defect density effect on the structural stability and the transport property under high pressure. In addition, the pressure effect on the band structure, density of states, and electronic states of the samples will be calculated. Based on above researches, we can summarize the phase transformation mechanism of Cu2X and CunX (1<n<2，X=S, Se, Te), reveal the relations between the structure and the physical properties. All of these investigations are significant and will provide a novel insight for material design, performance improvement and application in an extreme environment.

铜基二元金属硫族化合物在催化、光伏器件和储能材料等领域有广泛的应用前景，对其高压下的结构相变以及电学性质变化的研究是目前凝聚态物理研究的前沿问题之一。本项目拟采用高压拉曼光谱和高压X射线衍射实验，研究Cu2X及CunX（1<n<2，X=S, Se, Te）的压致结构相变；并结合高压Hall效应测量，对其高压下载流子浓度、电阻率、霍尔迁移率等电学参量进行系统表征，探讨结构相变过程中载流子输运性质的变化，探索压致金属化相变，研究高压下晶体缺陷密度对材料结构稳定性及电输运性质的影响；同时通过理论计算研究材料的能带结构、态密度及电子状态的变化等。综合以上研究，总结此类材料的高压相变规律，揭示其结构和力学、电学等物理性质间联系，为此类材料的设计、性能的提高以及在极端条件下的应用提供新的思路和依据。

铜基二元金属硫族化合物在催化、光伏器件和储能材料等领域有广泛的应用前景，对其高压下的结构相变以及物性变化的研究是目前凝聚态物理研究的前沿问题之一。本项目采用高压同步辐射、高压吸收光谱以及高压原位电输运性质测量实验并结合理论计算，研究了高压下铜基二元金属硫化物的结构稳定性以及物性的压力效应，阐明了高压下样品（Cu1.8S，Cu2Se和Cu2-x Te）的结构相变规律，获得了压力对样品光学带隙以及电输运性质的调控作用，同时也获得了压力导致的Cu2Se由间接带隙半导体相→半金属相→金属相的电子结构相变行为。而在30 GPa内，其它两个样品并没有压致金属化相变发生。此外,项目进行期间还对铜基三元金属硫化物进行了研究，探明了黄铜矿结构CuInSe2的霍尔系数、霍尔迁移率和载流子浓度随压力的变化关系，并给予了合理的理论解释；获得了纤锌矿相亚稳结构CuInS2由无序→无序→有序的奇异相变行为，还探明了压力对其光学带隙、电输运性质以及光电响应的调控作用。项目执行期间共发表科学研究论文3篇，培养研究生3人，达到了项目预期的目标。