Identification of individual 13C isotopes of nitrogen-vacancy center in diamond by combining the polarization studies of nuclear spins and first-principles calculations

We determine the charge- and spin-density distributions of nitrogen-vacancy center in diamond for both the ground and excited states by ab initio supercell calculations yielding very good agreement with the experiment. We correctly determine the polarization of N-15 nuclear spin in the level anticrossing (LAC) mechanism. We show that LAC together with the accurate ab initio data can be used to identify the individual C-13 nuclei around the defect that can also reveal the dominant component of the precession vector responsible for the decoherence of the addressed nuclear-spin qubit.