We have studied the metastability of the antistructure (arsenic-antisite gallium-antisite) pair in GaAs using self-consistent, parameter-free total energy methods. Our calculations predict that this defect complex exhibits metastability similar to that of the isolated arsenic antisite. However, the antistructure pair has ionization levels in the band gap in the metastable configuration, unlike the isolated arsenic antisite. The ionization levels enable absorption of infrared light in the metastable state. The results are used to discuss and interpret the arsenic-antisite-type defects observed experimentally in electron-irradiated GaAs.Peer reviewe
