The N-vacancy center in diamond was a promising candidate for realizing the spin qubits concept in quantum information. Even though this defect was known for a long time, its electronic structure and other properties have not yet been explored in detail. The properties of the N-vacancy center in diamond were studied via density functional theory within the local spin density approximation by using super-cell calculations. While this theory was strictly applicable for ground state properties, it was possible to give an estimate for the energy sequence of the excited states of this defect. The hyperfine tensors in the ground state were also calculated. The results clearly show that (i) the spin density and the appropriate hyperfine constants were spread along a plane and unevenly distributed around the core of the defect and (ii) the measurable hyperfine constants could be found within about 7Å from the vacancy site. These results have important implications on the decoherence of the electron spin which was crucial in realizing the spin qubits in diamond.

Ab Initio Supercell Calculations on Nitrogen-Vacancy Center in Diamond - Electronic Structure and Hyperfine Tensors. A.Gali, M.Fyta, E.Kaxiras: Physical Review B, 2008, 77[15], 155206 (12pp)