The migration of Ga adatoms on a (111)A surface was investigated by calculating the total energy, at various absorption sites, using first-principles pseudopotential methods. The Ga-vacancy structure which had been experimentally observed was assumed to be the reconstructed surface structure. It had been expected that the Ga-vacancy sites would be the most stable ones for Ga adatoms, but the calculations showed that they were not. Mechanisms which stabilized the Ga-vacancy site were suggested to play an important role in epitaxial growth. On the basis of the predicted energy potential surface, the migration barrier height was estimated to be about 0.4eV. This was much lower than that for GaAs(001) surfaces, and was consistent with the observation of a long diffusion length for Ga adatoms on (111)A surfaces.

First-Principles Investigation of Ga Adatom Migration on a GaAs(111)A Surface A.Taguchi, K.Shiraishi, T.Ito: Journal of Crystal Growth, 1999, 201-202, 73-6