The effects of transition element doping on the thermoelectric properties of β-Zn4Sb3

Abstract

The effects of transition elements Fe, Co, and Ni on the electronic structure and thermoelectric properties of β-Zn4Sb3 were investigated by performing self-consistent ab initio electronic structure calculations within density functional theory and solving the Boltzmann transport equations within the relaxation time approximation. The results demonstrate that these transition elements with 3d orbitals could introduce giant sharp resonant peaks in the electronic density of states (DOS) near the host valence band maximum or conduction band minimum in energy. And these deliberately engineered DOS peaks result in a sharp increase of the room-temperature Seebeck coefficient of β-Zn4Sb3 by a factor of nearly 60, 80 and 130, respectively. Additionally, with the simultaneous decline of carrier thermal conductivity upon Co/Ni doping, potentially, at least, 1.21/1.13-fold increase in thermoelectric figure of merit of β-Zn4Sb3 at room temperature are achieved, indicating that the substitution of Co and Ni for Zn can effectively elevate thermoelectric performance of β-Zn4Sb3.