Structure and thermoelectric properties of the quaternary compound Cs2[PdCl4]I2 with ultralow lattice thermal conductivity

Abstract

We study the electronic structure and thermoelectric properties of Cs2[PdCl4]I2 with ultralow lattice thermal conductivity using first-principles calculations and the semi-classical Boltzmann transport theory. The coexistence of several ionic and covalent bonds in Cs2[PdCl4]I2 indicates a similar Zintl phase crystal structure. Cs2[PdCl4]I2 is an indirect-band semiconductor with high density of states near the valence band maximum, which leads to high Seebeck coefficients even at high carrier concentrations. The calculated transport properties of p-type Cs2[PdCl4]I2 are higher than that of the known high-performance thermoelectric material CuGaTe2. The combination of good transport properties and ultralow lattice thermal conductivity suggests that Cs2[PdCl4]I2 can be a promising p-type thermoelectric material.