Study of adsorption of Al atom on Si(1 1 1)7 × 7 surface

We investigated adsorption of an Al atom on the Si(1 1 1)7 × 7 surface by using a scanning tunneling microscope. The evaporated Al atom displaced a Si center adatom of the surface; the expelled Si atom diffused inside a half unit cell of the Si(1 1 1)7 × 7 surface. The adsorbed single Al atom, which shows bias voltage dependency, hopped among three center adatom sites inside the half unit cell. Ab initio molecular orbital method was used to investigate the adsorption of Al atom on the surface.