Electronic structures of theSi(001)2×3−Agsurface

Abstract

Electronic structures of the double- and single-domain $\mathrm{Si}\left(001\right)2\times 3-\mathrm{A}\mathrm{g}$ surfaces were investigated by angle-resolved photoelectron spectroscopy using synchrotron radiation. All the surface states related to Si dimers are shown to disappear upon forming the $2\times 3-\mathrm{A}\mathrm{g}$ phase. Instead, five surface-state bands are identified within the bulk band gap with binding energies 0.8–2.6 eV, whose dispersions are determined for symmetric lines of the surface Brillouin zone. The $\mathrm{Si}\left(001\right)2\times 3-\mathrm{A}\mathrm{g}$ surface is clearly shown to be semiconducting with a band gap larger than 0.8 eV. This result can be in significant conflict with the presently available structure models of this surface phase.