Ultra-low lattice thermal conductivity and high thermoelectric efficiency of K_3AuO

摘要

Based on the combination of first-principles calculations and Boltzmann transport equation, we investigated the thermal transport properties of K_3AuO 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 K_3AuO can be maintained at around 2 in a relatively wide carrier concentration of 5.5 × 10~(20)-1.2 ×10~(21) cm~(-3), which demonstrates the stable thermoelectric properties of K_3AuO.