First-principles calculation of the migration energy of a Ga adatom on an As-stabilized GaAs(001) surface

We investigated the microscopic processes of a Ga adatom migration on an As-stabilized GaAs(001) surface. The adiabatic potential surface of a Ga adatom migration was calculated by the first-principles pseudopotential method on the basis of local density functional formalism. We found that the most stable Ga adsorption site is on the missing As dimer row and that the most favorable migration pass is in the [1¯10] direction through the missing As dimer row. The calculated activation barriers of a Ga adatom migration were 0.2 and 0.6 eV in the [1¯10] and [110] directions, respectively.