In order to investigate the lattice distortion caused by point defects in As-rich material, a self-consistent charge density-functional based tight-binding method was used. Both relevant defects, the As antisite and the As interstitial, caused significant lattice distortion. Unlike As interstitials, isolated As antisites led to lattice strains as well as to displacements of nearest-neighbor As lattice atoms into <110> channels; in excellent agreement with experiment. It was therefore concluded that the present results furnished strong evidence for As antisites being the predominant defects in as-grown As-rich GaAs.

Do Arsenic Interstitials Really Exist in As-Rich GaAs? T.E.M.Staab, R.M.Nieminen, J.Gebauer R.Krause-Rehberg, M.Luysberg, M.Haugk, T.Frauenheim: Physical Review Letters, 2001, 87[4], 045504 (4pp)