First principles electronic band calculation of (Zn, Cr)Te, (Zn, Cr)Se and (Zn, Cr)S

Electronic band structure of magnetic semiconductors based on II–VI compounds such as Zn1−xCrxX (X=Te, Se, S; x=1, 0.5, 0.25) are calculated for non-magnetic (NM), ferromagnetic (F) and antiferromagnetic (AF) states by using the full-potential linearized augmented-plane-wave method. In the F state, the half-metallic behavior is found in hypothetical zinc-blende type CrTe and CrSe and also in Zn0.5Cr0.5Te and Zn0.75Cr0.25Te. CrS shows metallic behavior. The magnetic polarization antiparallel to the Cr moment is induced at the neighboring Te, Se and S sites, respectively, and a magnitude of the induced moment decreases in the order of CrTe, CrSe and CrS. By calculating the total energy of each state, we have found that in all compounds, the F state is stable compared with the NM state. Furthermore, in the case of x=1, by comparing the total energy of the F state with that of the AF state described by Q=(0,0,2π/a), we have found that the F state is most stable in CrTe and CrSe and the AF state is stable in CrS. The AF band calculations for x=0.5 and 0.25 remain as a future problem.