Electronic Band Structure of Cadmium Chromium Chalcogenide Spinels: $CdCr_2$$S_4$ and $CdCr_2$$Se_4$

We report ab initio band structure results for two chromium chalcogenide spinels, $CdCr_2$$S_4$ and $CdCr_2$$Se_4$. Electronic structures have been calculated for both the nonmagnetic and the ferromagnetic states. The calculations correctly predict $CdCr_2$$Se_4$ to be a ferromagnetic insulator. The results for $CdCr2$$S_4$ correspond to a ferromagnetic semimetallic ground state, with very low density of states at the Fermi energy and a nearly gapped structure. Strong exchange splitting in both compounds suggests the possibility of realizing a half-metallic ferromagnetic state in doped Cr chalcogenide spinel