Intrinsically high thermoelectric figure of merit of half-Heusler ZrRuTe

Abstract

The electronic structure and thermoelectric properties of ZrRuTe-based half-Heusler compounds are studied using density functional theory and Boltzmann transport formalism. Based on rigorous computations of electron relaxation time τ considering electron-phonon interactions and lattice thermal conductivity κ l considering phonon-phonon interactions, we find ZrRuTe to be an intrinsically good thermoelectric material. It has a high power factor of ∼ 2 × 10 −3 W m −1 K −2 and low κ l ∼ 10 W m −1 K −1 at 800 K. The thermoelectric figure of merit ZT ∼ 0.13 at 800 K is higher than similar other compounds. We have also studied the properties of the material as a function of doping and find the thermoelectric properties to be substantially enhanced for p-doped ZrRuTe with the ZT value raised to ∼ 0.2 at this temperature. The electronic, thermodynamic, and transport properties of the material are thoroughly studied and discussed.