Surface states of ordered Au, Ag, and Cu overlayers on Si(111) studied by inverse photoemission

The {}3×{}{}3-Au, {}3×{}{}3-Ag, "5×{}5"-Cu, and 6×{}6-Au overlayer interfaces on Si(111) are studied with k-resolved inverse photoemission. Strong surface-state emission is observed at {}2.0 eV above the Fermi level for all these surfaces, which is attributed to the local bonding between the metal atoms and the Si(111) substrate. The long-range order of the larger unit cells manifests itself as weak surface states at the Fermi level.