Ab Initio Theory of Si-Vacancy Quantum Bits in 4H and 6H-SiC

Point defects in wide band gap semiconductors have outstanding potential for implementing room temperature quantum bits and single photon emitters. Silicon vacancy related color centers in 4H, 6H, and 15R-SiC are among the most studied quantum bits. The microscopic structures of these defects have been recently identified as isolated negatively charged silicon vacancy defects at the symmetrically non-equivalent silicon sites in SiC. In this study, high precision ab initio simulations on negatively charged silicon vacancies in 4H and 6H-SiC were done. The most important magneto-optical data, such as the zero-phonon photoluminescence energies, the zero-field-splitting, and the hyperfine tensors for the nearest and farther nuclear spins were estimated