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

¹ College of Physics and Electronic Engineering, Henan Normal University - Xinxiang, Henan 453007, China
² School of Physics Science and Engineering, Tongji University - Shanghai 200092, China
³ College of Physics and Electrical Engineering, Anyang Normal University - Anyang, Henan 455000, China

^(a) l001wf@gmail.com

Received: 25 January 2016
Accepted: 21 March 2016

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.