First-principles calculations were performed for 3d transition metal point defects and for defect pairs in group-III nitrides. Particular emphasis was placed on charge transfer energies, hyperfine interactions and internal optical transition energies. Linear muffin-tin orbital atomic sphere approximation Green’s function total energy calculations showed that VacN-TM pairs were tightly bound in semiconducting and in n-type material; with pair-formation energies above 1eV. It was shown that, within the framework of density functional theory, reliable total energies were obtained for excited states if the levels were represented by a single determinantal state within a 3dN basis. The derived optical transition energies agreed quite well with experimental observations.

Transition Metal Defects in Group-III Nitrides: an ab initio Calculation of Hyperfine Interactions and Optical Transitions. U.Gerstmann, A.T.Blumenau, H.Overhof: Physical Review B, 2001, 63[7], 075204 (9pp)