Cation antisite defects and antisite-interstitial complexes in gallium arsenide.

The atomic geometries of Ga and B antisites in GaAs are proposed to be strongly bistable. As the Fermi level is lowered towards the valence-band maximum, a structural change from fourfold to threefold coordination is predicted to occur. The Ga antisite is found to be metastable with respect to atomic exchange in the presence of an As interstitial. The antisite-interstitial complex has a large 2.9-eV binding energy but a small 0.3-eV barrier to Ga-As exchange.