Magnetic-field enhanced high-thermoelectric performance in topological Dirac semimetal Cd$_3$As$_2$ crystal

TL;DR

This study demonstrates that applying a magnetic field significantly enhances the thermoelectric efficiency of the topological Dirac semimetal Cd$_3$As$_2$, achieving over sixfold increase in the figure of merit at 350 K.

Contribution

It reveals that magnetic fields can simultaneously improve power factor and reduce thermal conductivity in topological Dirac semimetals, leading to high thermoelectric performance.

Findings

ZT increased from 0.17 to 1.1 at 350 K under 7 Tesla magnetic field

Magnetic field enhances power factor and reduces thermal conductivity

Large Fermi velocity and electric thermal conductivity contribute to ZT enhancement

Abstract

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 Cd$_3$As$_2$ 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 Tesla. 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 Cd$_3$As$_2$. Our work paves a new way to greatly enhance the thermoelectric performance in the quantum topological materials.