Theory of quasiparticle surface states in semiconductor surfaces.

A first principles theory of the quasiparticle surface state energies on semiconductor surfaces is developed. The surface properties are calculated using a repeated slab geometry. Many- body effects due to the electron-electron interaction are represented by the electron self energy operator including the full surface Green's function and local fields and dynamical screening effects in the Coulomb interaction. Calculated surface state energies for the phototypical Si(111):As and Ge(111):As surfaces are presented. The calculated energies and dispersions for the occupied surface states (resonances) are in excellent agreement with recent angular resolved photoemission data.