Structural Energies of A1 Deposited on the GaAs(110) Surface

Major controversies over the structure of A1 atoms deposited on the GaAs(110) surface have been resolved by using a first-principles energy-minimization method. The most stable configuration is that of A1 atoms replacing the second layer Ga atoms beneath the surface. At temperatures where this reaction cannot be activated, two important processes are found to exist. In the low-coverage limit, A1 atoms favor twofold sites to form strong bonds with the substrate atoms. At higher coverages, A1 atoms tend to cluster and make new bonds among themselves.