Electronic structure and optical properties of the new β-CdCr2O4 phase

The electronic and optical properties of beta-CdCr2O4 were studied through a periodic spin-polarized Density Functional Theory scheme using a hybrid PBE-type functional. Energy bands reveal the spin-selective semiconductor nature of this crystalline phase, which presents two different band gaps for the spin-up and spin-down states, 1.87 eV and 3.25 eV respectively. From the analysis of the density of states (DOS), it is found that the main contributions around the Fermi level arise from Cr and O atoms, but particularly from the triple degenerate t(2)g spin-up orbitals associated to Cr-1 atom. Furthermore, the dielectric function reported here shows that the optical absorption properties of this material are anisotropic, in agreement with the behavior shown by band structure data.