Ab initio total-energy calculations have been performed for the energetics and diffusion of surface vacancies on GaAs(110). The energies required to evaporate a Ga atom, an As atom, and a GaAs dimer are 4.9, 5.4, and 6.5 eV, respectively, in the neutral state. After evaporations, relaxations of the surface are substantial. The vacancies favor negatively charged states. The diffusion of the vacancies was examined by calculating the potential-barrier heights.

• Received 1 February 1995

DOI:https://doi.org/10.1103/PhysRevB.51.11198