Symmetry properties and band structure of surface states on the single-domain, hydrogen-chemisorbed Si(100) 2 × 1:H surface

Abstract

The surface electronic band structure and symmetry of surface states on the Si(100)2×1:H (monohydride) surface have been studied with polarization-dependent angle-resolved photoemission. By using Si samples cut 4° off the (100) plane, tilting towards the [011] direction, a single-domain 2×1:H surface was obtained. Three dispersing hydrogen-induced surface-state or resonance bands were observed in the energy range 4.7-6.5 eV below the Fermi level. By using a linearly polarized light source, the symmetry properties of these structures were determined along the main symmetry axes of the surface Brillouin zone. Based on the observed symmetries and theoretical considerations, we attribute two of the H-induced structures to Si-H bond states, derived from the bonding (${\pi }_b$) and antibonding (${\pi }_a$) dangling bonds of the clean surface shifted down in energy ∼4.5 eV by the hydrogen adsorption.