Ab initio study of the split silicon-vacancy defect in diamond: Electronic structure and related properties

The split silicon-vacancy (SiV) defect in diamond is an electrically and optically active color center. Recently, it has been shown that this color center is bright and can be detected at the single defect level. In addition, the SiV defect shows a nonzero electronic spin ground state that potentially makes this defect an alternative candidate for quantum optics and metrology applications beside the well-known nitrogen-vacancy color center in diamond. However, the electronic structure of the defect, the nature of optical excitations and other related properties are not well understood. Here we present advanced ab initio study on SiV defect in diamond. We determine the formation energies, charge transition levels, and the nature of excitations of the defect. Our study unravels the origin of the dark or shelving state for the negatively charged SiV defect associated with the 1.68-eV photoluminescence center.