Structural, electronic and optical properties of Zn0.5Cr0.5S from first-principles

The structural, magnetic, electronic and optical properties of the Zn0.5Cr0.5SZB, Zn0.5Cr0.5SW and Zn0.5Cr0.5SRS are studied by spin-polarized first-principles calculation. After optimization Zn0.5Cr0.5SZB system changes its original cubic structure of ZnSZB to a tetragonal structure, while Zn0.5Cr0.5SW and Zn0.5Cr0.5SRS still remain their original hexagonal structure of ZnSW and tetragonal structure of ZnSRS, respectively. The total moments of these Cr doped ZnS systems are mainly contributed by local magnetic moments of Cr2+ ion. Zn0.5Cr0.5SZB, Zn0.5Cr0.5SW and Zn0.5Cr0.5SRS are all half-metal with 100% spin polarization. The Zn0.5Cr0.5SW has the biggest static dielectric constant ɛ1(0) and refractive index n(0). The Zn0.5Cr0.5SZB, Zn0.5Cr0.5SW and Zn0.5Cr0.5SRS have tow absorption regions in the ranges of 0–27 eV and 41–55 eV, but the absorption width decreases for Zn0.5Cr0.5SW, Zn0.5Cr0.5SZB and Zn0.5Cr0.5SRS successively. The results will give a guide for design and application of the Zn0.5Cr0.5SZB, Zn0.5Cr0.5SW and Zn0.5Cr0.5SRS in spintronic devices and optical detectors.