Half metallic ferromagnetism in (Mn,Cr) codoped ZnS dilute magnetic semiconductor: First principles calculations

Abstract

We have investigated the half metallic ferromagnetism in (Mn,Cr) codoped ZnS using first principles calculations. While, Cr doped ZnS (ZnS:Cr) exhibits half-metallic ferromagnetic character, Mn doped ZnS (ZnS:Mn) is not found to be half-metallic. When Cr codoped to ZnS:Mn, it is found to transform into a half-metallic ferromagnetic semiconductor. The effect of occupation of Cr and Mn at two different sites of Zn atoms has brought out conspicuous difference in the band structure and density of states. The positional differences of Cr and Mn give rise to different characteristics, while in one case half-metallic nature is shown, in other case, there is no half-metallic nature. The half-metallic (Mn,Cr) codoped ZnS shows 100% spin polarization. Exchange constants clearly illustrates that all the compounds are in ferromagnetic order and the ferromagnetic coupling is mediated through the direct exchange interaction.