The metastability of the anti-structure (As-antisite, Ga-antisite) pair was studied by using self-consistent parameter-free total energy methods. The calculations predicted that this defect complex would exhibit a metastability which was similar to that of the isolated As antisite. However, the anti-structure pair had ionization levels in the band gap in the metastable configuration; unlike the isolated As antisite. The ionization levels permitted the absorption of infra-red light in the metastable state. The results aided the interpretation of As antisite-type defects which were observed experimentally in electron-irradiated GaAs.
S.Pöykkö, M.J.Puska, R.M.Nieminen: Physical Review B, 1997, 55, 6914-7