Enhanced Thermoelectric Properties of Dirac Semimetal Cd3As2

TL;DR

This study uses Boltzmann transport theory to analyze how doping affects the thermoelectric properties of topological semimetal Cd3As2, revealing significant improvements in ZT with optimized electron and hole doping levels.

Contribution

It provides a theoretical analysis of doping effects on thermoelectric performance of Cd3As2, highlighting optimal doping levels for enhanced ZT.

Findings

Electron doping increases ZT to about 0.5 at 700 K.

Hole doping shifts the Seebeck coefficient and improves ZT at 500 K.

Pristine Cd3As2 has a maximum ZT of around 0.15.

Abstract

We report an investigation of temperature- and doping-dependent thermoelectric behaviors of topological semimetal Cd3As2. The electrical conductivity, thermal conductivity, Seebeck coefficient, and figure of merit (ZT) are calculated by using Boltzmann transport theory. The calculated thermoelectric properties of the pristine Cd3As2 match well the experimental results. The electron or hole doping, especially the latter, is found improving much the thermoelectric behaviors of the material. The optimum merit ZT of Cd3As2 with electron doping is found to be about 0.5 at T=700 K with n=1x1020 cm-3, much larger than the maximum experimental value obtained for the pristine Cd3As2 (~0.15). For the p-type Cd3As2, the maximal value of the Seebeck coefficient as a function of temperature increases apparently with the increase of the hole doping concentration and its position shifts drastically towards the lower temperature region compared to that of the n-type Cd3As2, leading to the optimum merit ZT of about 0.5 obtained at low temperature of 500K (p=1x1020 cm-3) in the p-type Cd3As2.