Thermoelectric properties of A2BCl6: A first principles study

Abstract

Structural parameters, electronic band structures and thermoelectric properties of A2BCl6(A = Cs, K and B= Se, Sn, Ta, Te, Ti, W, Zr, Mn, Mo, Os, Pd, Pt, Re, Ru, Tc, W) materials at zero pressure and elevated temperatures have been studied. The computations have been presented within the density-functional theory using the CASTEP code. The obtained results are generally found to be in good agreement with the available data in the literature. Other case, our results are predictions. The calculated lattice parameters are found to be less than 3% with those of experiments. The Cs2BCl6(BSe, Sn, Te, Ti, Zr) and K2BCl6(B= Pd, Pt, Sn) materials are found to be semiconductors with a band gap energy varying from 3.14 to 5.00 eV. A metallic character is observed in Cs2BCl6(BTa, W) and K2BCl6(BTa, W, Mn, Mo, Os, Re, Ru, Ta, Tc) compounds indicating the presence of conductivity features. The thermoelectric (TE) properties like thermal conductivity (k), electrical conductivity (σ) and Seebeck coefficient (S) are also computed by using BoltzTrap code. The results indicate that given materials would be suitable candidates for thermoelectric (TE) and optoelectronic applications.