Stability and molecular pathways to the formation of spin defects in silicon carbide

Spin defects in wide-bandgap semiconductors provide a promising platform to create qubits for quantum technologies. Their synthesis, however, presents considerable challenges, and the mechanisms responsible for their generation or annihilation are poorly understood. Here, we elucidate spin defect formation processes in a binary crystal for a key qubit candidate—the divacancy complex (VV) in silicon carbide (SiC). Using classical and ab initio molecular dynamics with enhanced sampling techniques, we characterize the formation mechanism of VV. We then predict the conditions favoring the formation of divacancies over the competing process of mono-vacancy formation. Moreover, we identify pathways to create new spin defects and determine their electronic properties using hybrid density functional calculations. The detailed view of the mechanisms that underpin the formation and dynamics of spin defects presented here may facilitate the realization of qubits in an industrially relevant material.