Influence of varying Germanium content on the optical function dispersion of Fe2MnSixGe1−x: An ab initio study

► The optical dielectric functions of Fe2MnSi1−xGex were investigated. ► Fe2MnSixGe1−x is semiconducting for majority spin and is metallic for minority spin. ► The total magnetic moment is found to be 3.0μB for all alloys. ► The edge of optical absorption for ε2(ω) of spin-down varies between 0.507 and 0.547 eV. ► Since the spin-up shows metallic nature, the Drude term was included.