Diluted effect on the structural, magnetic, electronic, thermodynamic, optical and thermoelectric properties of the Heusler alloys Co2Fe1−xTixGa: GGA and GGA + U approaches

The structural, magnetic, electronic, thermodynamic, optical and thermoelectric properties of the Heusler Co2Fe1−xTixGa are investigated using the full potential linearized augmented plane-wave method within density functional theory. For exchange correlation potential, we have used GGA and GGA + U approximations. Our investigation on the influence of transition metals elements doping on lattice constant, bulk modulus and band gap for quaternary alloys shows a linear dependence on alloy composition with a small deviation. The calculated lattice parameter showed in good agreement with the experimental data, the spin magnetic moments is found to be in good agreement with Slater-Pauling rule and in their equilibrium L21 structure, all concentrations are half-metallic using GGA + U scheme. Moreover, the thermodynamic effects have been investigated such as the pressure and temperature effects on the structural parameters. The optical parameters as well as the thermoelectric properties of the Co2Fe1−xTixGa in the temperature range of 300–900 K have been studied.