Theoretical investigation of charge transfer between the NV− center in diamond and substitutional N and P

Abstract

The nitrogen-vacancy (N$V$ ) lattice defect in diamond, consisting of an N substitutional atom and an adjacent C vacancy, is commonly observed in two charge states, negative (N$V^{-}$ ) and neutral (N$V^0$ ). The N$V^{-}$ defect exhibits spin state-dependent fluorescence and is, therefore, amenable to optical methods for spin-state readout, while the N$V^0$ is not. Hence, the N$V^{-}$ defect is much more useful for quantum sensing and quantum information processing. However, only N$V^0$ electroluminescence has been observed, even from centers showing N$V^{-}$ in photoluminescence. In the present work, we use first-principles electronic structure calculations to determine adiabatic charge transition levels for the conversion of N$V^{-}$ to N$V^0$ in the presence of substitutional N or P impurities, which provide the charge of the N$V^{-}$ center. We find that the adiabatic charge transition levels in the presence of such impurities lie at energies close to or lower than the zero-phonon line of the N$V^{-}$ center and that these energies only decrease as the concentration of N donors increases. This work, therefore, elucidates the absence of observed electroluminescence from the N$V^{-}$ and proposes a path toward observation of the phenomenon.