Atomic and electronic structures of Si(1 1 3)1×1-Sb surface: core-level shifts and surface states

Atomic and electronic structures of a Si(1 1 3)1×1-Sb surface are investigated by synchrotron-radiation photoelectron spectroscopy. The Si 2p and Sb 4d core levels as well as the valence band dispersions are measured. All the components of the Si 2p core level spectrum related to the clean surface have been disappeared and one Sb-induced component could be identified at a higher binding energy of about +0.17 eV with respect to the bulk component. The Sb 4d core level spectrum is well represented by one doublet component, characteristic of Sb atoms adsorbed in an unique environment. For the electronic structure of the 1×1-Sb surface, single surface state positioned at 1.1 eV below the Fermi level at Γ, is recognized by angle-resolved photoemission spectroscopy and the dispersions has been mapped along the main symmetric directions in the surface Brillouin zone. The state shows a strong parabolic dispersion of about 0.95 eV along the [1 −1 0] direction while, in the [3 3 −1] direction, the state showed only small dispersion of about 0.35 eV. The 1×1-Sb surface shows a strong chemical passivation, which is due to the absence of the surface dangling bonds. In order to explain the results of the core level shifts, the band dispersions, and the surface inertness, simple structure model is suggested.