Ultra-low lattice thermal conductivity and high thermoelectric efficiency of K3AuO

Abstract

Based on the combination of first-principles calculations and Boltzmann transport equation, we investigated the thermal transport properties of K3AuO and predicted a figure of merit ZT=2.01 at 700 K with p-type doping. Such a high thermoelectric efficiency can be attributed to the ultra-low lattice thermal conductivity with a value of 0.48 Wm−1 K−1 at 300 K, and detailed research shows that the low lattice thermal conductivity arises from the small phonon group velocity and high scattering rates; moreover, the figure of merit ZT of p-type doped K3AuO can be maintained at around 2 in a relatively wide carrier concentration of 5.5×1020–1.2×1021 cm−3, which demonstrates the stable thermoelectric properties of K3AuO.