Theory of spin polarization of the silicon vacancy center in hexagonal SiC

Silicon carbide-based defects are promising for quantum communications and for the next generation of quantum sensors, as they feature long coherence times, frequencies at the telecom, and optical and microwave transitions. We analyze the symmetry-adapted many-body wave functions of the V_{Si} in hexagonal SiC and calculate the inter system crossing (ISC) mechanism, enabled by spin-orbital coupling and phonon assisted relaxation. Our results provide a fundamental explanation of the initialization and readout of the silicon vacancy, key processes for quantum sensing and quantum information processing based on this system.