Thermodynamic and thermoelectric properties of FeCrTiZ (Z = Si, Ge) quaternary Heusler compounds

Abstract

The objective of this work is to find the possible applications of the compounds as thermoelectric materials or alternate energy materials. In this regard, FeCrTiZ (Z = Si, Ge) quaternary Heusler compounds have been analyzed via investigating their stable structure and other physical properties by using comprehensive density functional theory executed in the WIEN2k package. The optimized lattice constants and other ground state parameters are found to be concurrent with the existing data. The spin-embraced electronic properties lead to the half-metallic character of the compounds on account of different behavior of the two spins. The obtained total magnetic moment ideally follows the Pauling-Slater rule and is also congruent to the available data. Furthermore, to study the lattice vibrational properties, the dependence of unit cell volume, bulk modulus, Debye temperature, and Gruneisen constant has been estimated within a certain temperature and pressure range by employing a Debye model of quasi-harmonic approximation. The thermoelectric parameters have also been estimated by employing the BoltzTrap code which gives significant values of the figure of merit for both compounds.