Effect of Mn doping on the electronic structure of ZnGa2O4 with spinel-type structure

The electronic structures of ZnGa2O4 and ZnGa2O4:Mn are calculated by the d iscrete variational X alpha method on model clusters. For ZnGa2O4, it is fo und that Zn-O and Ga-O bondings are not perfectly ionic but partially coval ent. When a central Zn atom of the cluster is replaced with a Mn atom, the new energy states originating from Mn 3d orbitals appear in the energy gap. The energy levels of t(2) up-spin states and e down-spin states seem to re late to the green emission.