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 κl 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 κl ∼ 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.