Atomic and electronic structures of surface kinks on GaAs(001) surfaces

We investigate the atomic and electronic structures of surface dimer kinks using the ab initio calculations. We investigated the (2 × 4) and the c(2 × 8) dimer kink models. The calculated results show that weak As dimers are formed at (2 × 4) dimer kinks by the de-stabilization of occupied As dangling bond states and that (2 × 4) dimer kinks become favorite Ga adsorption sites during epitaxial growth. On the other hand, no weak As dimers are formed at c(2 × 8) dimer kinks. However, Ga adsorption at the c(2 × 8) dimer kinks induces the weak As dimer formation. Consequantly, c(2 × 8) dimer kinks also act as reactive Ga adsorption sites during epitaxial growth as well as the (2 × 4) dimer kinks.