First-principles calculations of Mn incorporation into GaAs(110)

Mn substitution reaction on the GaAs(110), observed in experiments, has been verified by first-principles pseudopotential calculation based on the spin density functional theory. Adsorption energy, substitution energy, desorption energy, and migration energies have been evaluated, and energy changes in each process were investigated in detail. We have found that the adsorption and substitution processes proceed with decreasing the total energy. However, it is considered that the Ga released by the substitution reaction migrate on the surface because the desorption energy of Ga atom is large. Furthermore, it has been found that spin densities of adsorbed Ga on the GaAs(110) surface distribute in the direction parallel to the surface, and the most stable position of adsorption Ga is slightly away from Mn site due to the magnetic interaction with the topmost surface Mn.