Low lattice thermal conductivity and high figure of merit in p-type doped K₃IO

Based on first-principles calculations, Boltzmann transport equation and semiclassical analysis, we conduct a detailed study on the lattice thermal conductivity \kappa_\rm L, Seebeck coefficient S, electrical conductivity σ, power factor S²σ and dimensionless figure of merit, zT, for K₃IO. It is found that K₃IO exhibits relatively low lattice thermal conductivity of 0.93 Wm^-1K^-1 at 300 K, which is lower than the value 1.26 Wm^-1K^-1 of the classical TE material PbTe. This is due to the smaller phonon group velocity Ν _g and smaller relaxation time τ_Λ. The low lattice thermal conductivity can lead to excellent thermoelectric properties. Thus maximum zT of 2.87 is obtained at 700 K, and the zT=0.41 at 300 K indicate that K₃IO is a potential excellent room temperature TE material. Our research on K₃IO shows that it has excellent thermoelectric properties, and it is a promising candidate for applications in fields in terms of thermoelectricity.