Fermi-level pinning and surface-state band structure of the Si(111)-(√3×√3)R30°-Ag surface

The surface-state band structure and symmetry properties of the Si(111)-({}3 ×{} {}3) R30^∘{}-Ag surface have been studied with polarization-dependent, angle-resolved photoemission. In contradiction to the prevailing picture of this surface, we find an intrinsic, dispersive surface-state band in the bulk band gap. The minimum of this band is located 0.1 eV above the valence-band maximum (EV), and the observed partial occupation of the band determines the Fermi-level position (0.2 eV above EV) on this surface.