ELECTRONIC-STRUCTURES OF THE SI(001)2X3-AG SURFACE

Electronic structures of the double-and single-domain Si(001)2X3-Ag su rfaces were investigated by angle-resolved photoelectron spectroscopy using synchrotron radiation. All the surface states related to Si dime rs are shown to disappear upon forming the 2X3-Ag phase. Instead, five surface-state bands are identified within the bulk band gap with bind ing energies 0.8-2.6 eV, whose dispersions are determined for symmetri c lines of the surface Brillouin zone. The Si(001)2X3-Ag surface is cl early shown to be semiconducting with a band gap larger than 0.8 eV. T his result can be in significant conflict with the presently available structure models of this surface phase. [S0163-1829(98)01907-9].