Tuning the electronic and optical properties of Co2TiGe Heuslerene by selecting Ge- or Ti- termination structure

In this work, the Ge- and Ti-termination monolayers of Co2TiGe were investigated by density functional theory. The phonon dispersion curves of these monolayers revealed their dynamical stability. The calculated spinresolved density of states and band structure of the monolayers confirmed the asymmetrical pattern of spinup and spin-down showing the magnetic as well as the half-metallic characters of these monolayers. The calculated optical properties of the Ge- and Ti-termination monolayers of Co2TiGe by the Bethe-Salpeter equation showed the absorption of Ge-termination in the visible region of the electromagnetic spectrum which was extended to the UV region in the Ti-termination monolayer.