Wang Honghui, Luo Xigang, Chen Weiwei, Wang Naizhou, Lei Bin, Meng Fanbao, Shang Chao, Ma Likuan, Wu Tao, Dai Xi, Wang Zhengfei, Chen Xianhui
Hefei National Laboratory for Physical Science at Microscale and Department of Physics, University of Science and Technology of China, and Key Laboratory of Strongly-coupled Quantum Matter Physics, Chinese Academy of Sciences, Hefei 230026, China.
Physics Department, Hong Kong University of Science and Technology, Hong Kong, China.
Sci Bull (Beijing). 2018 Apr 15;63(7):411-418. doi: 10.1016/j.scib.2018.03.010. Epub 2018 Mar 21.
Thermoelectric materials can be used to convert heat to electric power through the Seebeck effect. We study magneto-thermoelectric figure of merit (ZT) in three-dimensional Dirac semimetal CdAs crystal. It is found that enhancement of power factor and reduction of thermal conductivity can be realized at the same time through magnetic field although magnetoresistivity is greatly increased. ZT can be highly enhanced from 0.17 to 1.1 by more than six times around 350 K under a perpendicular magnetic field of 7 T. The huge enhancement of ZT by magnetic field arises from the linear Dirac band with large Fermi velocity and the large electric thermal conductivity in CdAs. Our work paves a new way to greatly enhance the thermoelectric performance in the quantum topological materials.
热电材料可通过塞贝克效应将热量转化为电能。我们研究了三维狄拉克半金属CdAs晶体中的磁热电优值（ZT）。研究发现，尽管磁电阻率大幅增加，但通过磁场可同时实现功率因子的增强和热导率的降低。在7 T的垂直磁场下，在350 K左右，ZT可从0.17大幅提高到1.1以上，提高了六倍多。磁场对ZT的巨大增强源于具有大费米速度的线性狄拉克能带以及CdAs中较大的电热导率。我们的工作为大幅提高量子拓扑材料中的热电性能开辟了一条新途径。
