  The silicon vacancy is a prominent intrinsic defect of cubic SiC (3C-SiC) to
which much effort has been devoted so far, experimentally and theoretically. We
calculate its properties using the GW approximation that does not suffer from
the band gap problem. The obtained formation and transition energies deviate
significantly from the usual density functional theory evaluations and now
compare favorably with experiment. A new assignment for the main line of
photoluminescence is then proposed. We further perform GW calculations for the
saddle point of reaction paths. The resulting barrier energies explain the
thermal annealing experiments thanks to an original mechanism mediated by a
minority charge configuration.
