Rashba型热电材料中自旋劈裂效应与电热输运性质的研究

The key approach to achieve high thermoelectric performance is decoupling and optimizing the electrical and thermal transport properties. Recently, spin quantum effects bring about new freedom to the design of thermoelectric materials. In this project, the influences of Rashba spin-split effect on electrical/thermal transport and thermoelectric performance are studied. We explore new relativistic transport phenomena in the Rashba spin-split systems by combining material synthesis, transport characterizations, and theoretical calculations. The contribution of spin effects to the thermoelectric transport will be distinguished through controlling the strength of Rashba effect via lattice distortion and phase transition. Meanwhile, the impact of hidden Rashba effect on thermoelectric properties will be studied, which may achieve both band convergence and low-dimensional transport. This work will provide guidance for manipulating spin-related electrical/thermal transports and exploring new high-performance thermoelectric materials with relativistic quantum effects.

热电材料设计和性能优化的核心是实现电子和声子输运的协同调控。近年来，将电子内禀的自旋特性作为新的自由度引入电热输运调控备受关注。本项目研究Rashba自旋劈裂效应对电热输运与热电性能的影响规律和机制。结合Rashba型热电材料的制备、电热输运表征与理论计算，探索具有新奇量子特征的电热输运新效应；利用晶格畸变和相变分析自旋劈裂效应对电热输运的实质贡献，实现自旋效应与热电性能的协同调控；并关注具有晶格高对称性和局域对称性破缺的隐性Rashba体系，实现高能谷简并度和低维化输运的耦合。本项目有望为具有自旋效应的电热输运调控提供借鉴，推动具有新奇量子效应的高性能热电材料探索，具有重要的科学意义和实用价值。

自旋量子效应为热电材料的电热输运研究提供了新的自由度，为热电能量转换材料的开发提供新思路。其中，Rashba自旋劈裂效应来源于对称性破缺和自旋轨道耦合，对热电材料性能的影响是一个尚待进一步研究的课题。本项目研究基于具有Rashba效应的块体材料，如GeTe和BiTeI，结合第一性原理计算、材料制备和输运表征，阐明Rashba自旋效应对材料塞贝克系数、功率因子和热电性能的影响；利用选择性掺杂、相变调控Rashba材料的电子结构，实现电热输运和热电性能的协同优化；并初步尝试利用场效应调控Rashba材料的费米能级。本项目为对称性破缺材料的电热输运研究提供借鉴，推动具有新奇效应的高性能热电材料探索。