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 Cd₃As₂ 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 Cd₃As₂. Our work paves a new way to greatly enhance the thermoelectric performance in the quantum topological materials.

热电材料可用于通过塞贝克效应将热能转化为电能。我们研究了三维狄拉克半金属 Cd ₃ As ₂晶体中的磁热电品质因数 ( ZT )。发现虽然磁阻系数大大增加，但通过磁场可以同时实现提高功率因数和降低热导率。在 7 T 的垂直磁场下， ZT可以在 350 K 附近从 0.17 增强到 1.1 超过六倍。磁场对ZT的巨大增强来自具有大费米速度和大电热导率的线性狄拉克带在 Cd ₃ As ₂. 我们的工作为大大提高量子拓扑材料的热电性能开辟了一条新途径。