Electronic structure of a stepped semiconductor surface: Density functional theory of Si(114)-(2x1)

Ab initio density functional theory calculations, based on pseudopotentials and the plane-wave formalism, have been performed to investigate the equilibrium geometry, bonding, and electronic structure of the Si(114)-(2x1) surface, characterized by three prominent surface features (dimers, tetramers, and rebonded atoms). Several surface states are found in and around the bulk band gap. Mixing of the orbitals of the rebonded atoms with those of the dimers leads to a small band-gap surface.