Optically controlled switching of the charge state of a single nitrogen-vacancy center in diamond at cryogenic temperatures

P. Siyushev, H. Pinto, M. Vörös, A. Gali, F. Jelezko, and J. Wrachtrup

Accepted Tuesday Mar 26, 2013

In this paper, the photoinduced switching of the single nitrogen-vacancy (NV) center between two different charge states - negative (NV-) and neutral (NV0) is studied under resonant excitation at liquid helium temperature. We show that resonant conversion of NV0 to NV- significantly improves spectral stability of NV- defect and allows high fidelity initialization of the spin qubit. Based on DFT calculations a novel mechanism involving an Auger ionization of NV- and charge transfer of an electron from the valence band to NV0 is discussed. This study provides further insight into the charge dynamics of the NV center, which is relevant for quantum information processing based on NV defect in diamond.