(138b) Stability and Molecular Pathways to the Formation of Spin Defects in Silicon Carbide

Defects in solids with isolated electron spins are physical platforms for quantum technologies. Spin defects have been identified in divacancy complexes in silicon carbide (SiC), merging room-temperature coherent control of spins with large-scale synthesis capabilities of the host material. Little is known, however, of the high temperature conditions and mechanisms by which spin defects form in binary crystals. Here, we uncover the processes to form spin defects from vacancy complexes in SiC, by combining advanced sampling technique with atomistic models and density functional theory calculations. We show divacancy formation is governed by the interplay of thermally-induced monovacancy destabilization and the mobilization of individual defects. The predicted temperature-dependent behavior of vacancy defects agrees well with recent annealing experiments and photoluminescence measurements. We find divacancies can change their crystallographic orientations during thermal annealing without fully dissociating. We also identify new spin defects consisting of antisites and vacancies, and determine their electronic properties. 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.