Bai Feng-Xian, Yu Hao, Peng Ya-Kang, Li Shan, Yin Li, Huang Ge, Chen Liu-Cheng, Goncharov Alexander F, Sui Jie-He, Cao Feng, Mao Jun, Zhang Qian, Chen Xiao-Jia
School of Materials Science and Engineering, and Institute of Materials Genome & Big Data, Harbin Institute of Technology, Shenzhen, 518055, China.
Center for High Pressure Science and Technology Advanced Research, Shanghai, 201203, China.
Adv Sci (Weinh). 2022 May;9(14):e2105709. doi: 10.1002/advs.202105709. Epub 2022 Mar 15.
The electronic structure near the Fermi surface determines the electrical properties of the materials, which can be effectively tuned by external pressure. Bi Sb Te is a p-type thermoelectric material which holds the record high figure of merit at room temperature. Here it is examined whether the figure of merit of this model system can be further enhanced through some external parameter. With the application of pressure, it is surprisingly found that the power factor of this material exhibits λ behavior with a high value of 4.8 mW m K at pressure of 1.8 GPa. Such an enhancement is found to be driven by pressure-induced electronic topological transition, which is revealed by multiple techniques. Together with a low thermal conductivity of about 0.89 W m K at the same pressure, a figure of merit of 1.6 is achieved at room temperature. The results and findings highlight the electronic topological transition as a new route for improving the thermoelectric properties.
费米面附近的电子结构决定了材料的电学性质，而这种性质可通过外部压力有效调节。BiSbTe是一种p型热电材料，在室温下保持着创纪录的高品质因数。本文研究了该模型体系的品质因数是否能通过某些外部参数进一步提高。施加压力后，令人惊讶地发现，在1.8 GPa的压力下，这种材料的功率因数呈现出λ行为，其高值为4.8 mW m⁻¹ K⁻²。发现这种增强是由压力诱导的电子拓扑转变驱动的，这一点通过多种技术得以揭示。在相同压力下，该材料的热导率约为0.89 W m⁻¹ K⁻¹，室温下实现了1.6的品质因数。这些结果和发现突出了电子拓扑转变作为改善热电性能的一条新途径。
