Fermi-level pinning and surface-state band structure of the Si(111)-(√3×√3)<i>R</i>30°-Ag surface

Abstract

The surface-state band structure and symmetry properties of the Si(111)-(\ensuremath{\surd}3 \ifmmode\times\else\texttimes\fi{} \ensuremath{\surd}3) R30\ifmmode^\circ\else\textdegree\fi{}-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 (${E}_{V}$), and the observed partial occupation of the band determines the Fermi-level position (0.2 eV above ${E}_{V}$) on this surface.