Thermoelectric materials, which can transform heat energy into electrical one and vice-versa, have attracted broad attention over the past decades. Good thermoelectric materials should exhibit a high dimensionless figure of merit, $ZT$, defined as $ZT = S^2 T / \rho ( \kappa_e + \kappa_L )$, where $S$ is the Seebeck coefficient, $T$ is the absolute temperature, $\rho$ is the electronic resistivity, and $\kappa_e$ and $\kappa_L$ are the electronic and lattice thermal conductivity, respectively.

Lead chalcogenides and tin chalcogenides tend to be dominant thermoelectric materials in the medium-temperature (500-900K) range.

Because of a high-mixing entropy, the high-entropy alloys (HEAs), which contain multiple principal elements at equimolar or near equimolar ratios, often form random solid solutions with a simple body-centered cubic (BCC) or face-centered cubic (FCC) crystal structure. Due to chemical complexity and high configurational entropy, they usually exhibit severe lattice-distortion and high-temperature phase stability which could effectively reduce its lattice thermal conductivity. Therefore, one can suppose that HEAs possess intrinsically low lattice thermal conductivity and may be a class of promising thermoelectric materials.

In the present work, we have investigated HEA compounds comprising Pb, Sn, Te and Se elements. First we have used the ATAT suite of programs to build the possible structures then we have optimized these structures using ab initio DFT approach and calculated the electronic band structure with VASP. Finally, we have calculated the thermoelectric transport properties of these alloys using the Boltzmann transport theory as implemented in the BoltzTraP code.

We will present in this paper the details of the strategies adopted in our approach as well as the most prominent results.