High Pressure-Temperature study on thermodynamics, half-metallicity, transport, elastic and structural properties of Co-based Heusler alloys: A first-principles study

Abstract

Employing first-principles based on density functional theory, we have investigated thermodynamics, half-metallicity, transport, elastic and structural properties of Co2ScSb and Co2TiSb full-Heuslers at high temperature and pressure. The existence of perfect band structure and density of states through the modified version of Becke Johnson (mBJ) system delivers more precise and accurate results rather than GGA and GGA ​+ ​U for both these Heuslers. Structural optimizations support the stability in AlCu2Mn-prototype with space symmetry of Fm3−m (#225) space group in both these alloys. The density of states and band occupation describes the semiconducting nature. Co2ScSb and Co2TiSb possess an indirect band-gap of 1.08 ​eV and 1.32 ​eV respectively. The estimation of elastic constants and its other associated mechanical constituents exhibits ductile behavior along with high melting temperature. The thermoelectric coefficients are used to check the applicability of the material for waste heat recovery systems and technological purposes. Thermodynamic potentials which include heat capacity, thermal expansion and Grüneisen parameter have been keenly predicted by employing quasi harmonic Debye model to exhibit its stability at high temperature and pressure varying conditions. Hence, the overall theme of this current study creates an application stand in spintronics, power generation as well as green energy sources for future technologies.