New Models for Metal-Induced Reconstructions on Si(111)

Angle-resolved photoelectron spectroscopy and surface-core-level chemical shifts have been used to study electronic structure and derive structural models of the Al, Ag, and Ni metal-induced reconstructions on Si(111). We show, for the first time, the connection between the Ni-stabilized $\sqrt{19}\times \sqrt{19}$ and clean 7×7 surfaces, and report a new Si(111)-$(\sqrt{7}\times \sqrt{7})\mathrm{Al}$ structure at <0.5 monolayer coverage of Al.