Arsenic interstitials and interstitial complexes in low-temperature grown GaAs

First-principles molecular-dynamics calculations have been used to calculate the formation energy of the lowest-energy As interstitial configuration relative to the formation energies of As antisites and Ga vacancies in As-rich GaAs, and to identify and study the properties of energetically favorable complexes containing one As antisite and one As interstitial. It is suggested that the electronic and optical properties of the antisite-interstitial complexes match the properties of the defects responsible for the dominant donor band in some samples grown around 350 degrees C.