Evaluation of thermoelectric CdSnAs2 with intrinsically low effective mass

Abstract

The effective mass of band structure has been proven as a key parameter determining the electrical transport properties of thermoelectrics. Concretely, low effective mass along the transport direction always accompanies with a high carrier mobility, as well as an excellent electronic performance. This work focuses on n-type CdSnAs2, possessing an intrinsically low effective mass, for its potential as a thermoelectric material. A single Kane band model with acoustic phonon scattering not only enables an assessment of the electrical transport properties, but also provides a well understanding of its underlying physics. Benefited by the low effective mass, an extremely high Hall mobility of ∼4500 cm2/V-s is obtained in polycrystalline CdSnAs2, experimentally leading to a high power factor of ∼12 μW/cm-K2 at 600 K. Based on the model, an excellent peak zT is expectable through minimizing lattice thermal conductivity and optimizing carrier concentration, which demonstrates it as a promising thermoelectric material.