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Calculation ofthe transitions and migration of nitrogen and vacancy related defects,with implications on the formation of NV centers in bulk diamond

Formation and excitation energies as well charge transition levels, are determined forthe substitutional nitrogen (Ns),the vacancy (V) and related point defects (NV, NVH, N2, N2V and V2) by screened non-local hybrid density functional supercell plane wave calculations in bulk diamond. In additionthe activation energy for V and NV diffusion is calculated.We find good agreement between theory and experiment for the previously well-establisheddata, and predict missing ones. Based on the calculated properties of these defects, the formation of the negatively charged nitrogen-vacancy center is studied, which is a prominent candidate for application in quantum information processing and for nanosensors. We find that the concentration of NV defects are limited in natural diamonds due to the relatively high formation energy of NV. Our results imply that NV defects dominantly form just in the early stage of annealing in N-doped and irradiated diamonds. We find that the amphoteric divacancy defect with multiple acceptor states may significantly influence the charge state and photo-stability of NV in irradiated diamond samples.