Theoretical Evidence for an Optically Inducible Structural Transition of the Isolated As Antisite in GaAs: Identification and Explanation ofEL2?

We performed parameter-free, self-consistent calculations of the electronic structures, total energies, and forces of the As antisite, of an As-interstitial-Ga-vacancy defect pair, and of various configurations between these limits. The total-energy surface exhibits an interesting metastability. The theoretical results can explain all established properties of the so-called $\mathrm{EL}2\mathrm{}$ defect.