压致等结构相变的电输运特性研究

Novel physical phenomena usually appear during pressure induced isostructural phase transition, which provides a new way for understanding the mechanics and driving forces of high pressure transitions. Most previous studies on isostructural phase transition have focused on field of spectroscopy and structure analysis. In this research project, isostructural phase transition will be studied from the view of electrical transport. Electrical conductivity, carrier concentration, mobility, magnetoresistivity, and activation energy will be measured using in-situ electrical transport parameters measurement in a diamond anvil cell under high pressure. When pressure induced isostructural phase transition occurs, the information about electronic structure, electronic motion, and electronic interaction would be obtained by pressure dependences of the electrical transport parameters and the relationship between these parameters. We will also adopt in-situ X-ray diffraction measurement and first-principles calculation to reveal the physical essence of new effect of isostructural phase transition. The productions of this research project will provide a valuable chance to understand the basic rule of charge transfer and electronic tracks evolution under high pressure.

压致等结构相变伴随很多奇异的物理现象，它为人们理解高压相变的机制和驱动力提供新途径。以往对于等结构相变的研究多集中在光谱学和结构分析领域。本项从电输运的角度来研究等结构相变。利用基于金刚石对顶砧的多电学量联合测量方法，对电阻率、载流子浓度、迁移率、磁阻率、激活能等物理量进行原位测量。通过各物理量随压力变化关系和物理量之间的制约关系，获得等结构相变发生时电子的结构、运动、相互作用等微观信息。结合高压原位X射线衍射测量和第一性原理计算等研究手段，揭示伴随等结构相变发生时材料的高压新效应的物理本质。期望本项目的成果能帮助人们认识在压力作用下电荷转移、电子轨变迁的基本规律。

压致等结构相变为人们理解高压相变的机制和驱动力提供新途径。以往对于等结构相变的研究多集中在光谱学和结构分析领域。本项从电输运的角度出发,利用基于金刚石对顶砧的多电学量联合测量方法来研究等结构相变。通过各物理量随压力变化关系和物理量之间的制约关系，获得等结构相变发生时电子的结构和相互作用等微观信息。通过项目的实施建立了基于DAC的高压原位多电学量原位测量可靠的实验方法。通过测量过渡金属硫族化合物的高压原位测量高压下材料电阻率、载流子浓度、迁移率、激活能等电输运参量，对此类材料传导特性给出清晰的物理图像。第一性原理计算结合电输运参量随压力的变化关系总结出过渡金属硫族化合物在高压的作用下金属化传导的物理模型和等结构相变的机制。通过高原位同步辐射X射线衍射研究，我们分析了不同静水压环境对等结构相变压力的影响。本项目的成果能帮助人们认识在压力作用下电荷转移和电子轨变迁的基本规律。