The electronic and structural properties of certain defect complexes, which were created during electron or ion irradiation, were studied using an  ab initio  calculation which was based upon pseudopotential density-functional theory. A super-cell with 128 atoms in a Car-Parinello format was used. In the case of the antistructure pair, AsGa+GaAs, first donor, first acceptor, and second acceptor levels were deduced from the total-energy calculations, and a comparison was made with earlier theoretical and experimental results. Two other possible defect complexes, VAs+AsGa+Gai and VGa+GaAs+Asi, were considered. It was shown that the former was a metastable configuration, while the latter was unstable and exhibited spontaneous recombination.

A.Janotti, A.Fazzio, P.Piquini, R.Mota: Physical Review B, 1997, 56[20], 13073-6