ELECTRON-STATES OF AN Sb-ORDERED OVERLAYER ON GaAs(110)

The electronic properties of an Sb overlayer deposited onto a GaAs(110) surface have been calculated using a self-consistent-pseudopotential approach and assuming the ordered-overlayer geometry proposed in recent low-energy electron diffraction studies. The results show that Sb adatoms are bound by strong covalent bonds to the substrate and that various overlayer or chemisorption-induced states appear throughout the valence band. Comparison with photoemission data allows us to assign a major Sb-induced structure appearing in the energy distribution curves.