Breathing-mode relaxation associated with electron emission and capture processes ofEL2 in GaAs

Analysis of the effects of hydrostatic pressure on the electronic emission and capture properties of the (0/+) and (+/++) deep levels of the EL2 defect in GaAs leads to the following conclusions: (1) Both levels move higher in the band gap with pressure; (2) relatively large inward (outward) lattice relaxations accompany electron emission (capture) from (by) these levels; and (3) the magnitudes of the relaxations agree quantitatively with theoretical results which identify EL2 as the As antisite defect. These results which emphasize the antibonding character of the orbitals which describe EL2 are consistent with this identification.