Density functional theory calculations of electronic structure and thermoelectric properties of K-based double perovskite materials

Structural parameters, elastic constants, electronic band structures, and thermoelectric properties of K(2)ABF(6) (A = Ag, Na, B = Rh, Pd, Ni, Nb, Ru, Ti) materials at zero pressure and elevated temperatures have been studied. The computations have been presented within the density functional theory using the Cambridge Serial Total Energy Package code. Special attention has been given to the thermoelectric properties of the studied materials for K-based double perovskite materials. 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. All materials of interest are classified as ductile ones. An inspection of the band structure indicated that all materials under load are indirect bandgap semiconductors. The high Seebeck coefficient is shown by the semiconductors, while metals have the least Seebeck coefficient. The alloys possess high figure of merit (ZT) values, suggesting their applications in thermoelectric power generation.