Fu Chenguang, Guin Satya N, Scaffidi Thomas, Sun Yan, Saha Rana, Watzman Sarah J, Srivastava Abhay K, Li Guowei, Schnelle Walter, Parkin Stuart S P, Felser Claudia, Gooth Johannes
Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany.
Department of Physics, University of California, Berkeley, CA 94720, USA.
Research (Wash D C). 2020 Apr 7;2020:4643507. doi: 10.34133/2020/4643507. eCollection 2020.
Highly conductive topological semimetals with exotic electronic structures offer fertile ground for the investigation of the electrical and thermal transport behavior of quasiparticles. Here, we find that the layer-structured Dirac semimetal PtSn exhibits a largely suppressed thermal conductivity under a magnetic field. At low temperatures, a dramatic decrease in the thermal conductivity of PtSn by more than two orders of magnitude is obtained at 9 T. Moreover, PtSn shows both strong longitudinal and transverse thermoelectric responses under a magnetic field. Large power factor and Nernst power factor of approximately 80-100 W·cm·K are obtained around 15 K in various magnetic fields. As a result, the thermoelectric figure of merit is strongly enhanced by more than 30 times, compared to that without a magnetic field. This work provides a paradigm for the decoupling of the electron and hole transport behavior of highly conductive topological semimetals and is helpful for developing topological semimetals for thermoelectric energy conversion.
具有奇异电子结构的高导电拓扑半金属为准粒子的电输运和热输运行为研究提供了丰富的研究素材。在此，我们发现层状结构的狄拉克半金属PtSn在磁场下热导率大幅降低。在低温下，9 T磁场中PtSn的热导率急剧下降超过两个数量级。此外，PtSn在磁场下表现出强烈的纵向和横向热电响应。在不同磁场中，15 K左右可获得约80 - 100 W·cm·K的大功率因子和能斯特功率因子。结果，与无磁场时相比，热电优值大幅提高了30倍以上。这项工作为高导电拓扑半金属的电子和空穴输运行为解耦提供了一个范例，有助于开发用于热电能量转换的拓扑半金属。
