UNOCCUPIED ELECTRONIC STATES IN AU(100) SURFACES

We present a joint experimental and theoretical work on the empty states of Au(100) surfaces. Both the stable 5 x 10 reconstructed and the metastable defect-stabilized 1 x 1 surfaces have been investigated by means of angle-resolved inverse photoemission, and the electronic structure has been theoretically determined for the 1 x 1 surface within the local density approximation. The experimental spectra for the two surfaces are very similar, showing in both cases bulk derived transitions and a surface feature corresponding to the n = 1 image-potential state. In the spectra from the metastable surface, a strong n = 0 surface resonance is also observed. Comparison with theoretical calculations for the 1 x 1 surface gives generally good agreement for the bulk transitions, but suggests that surface defects strongly influence surface states localized near the surface layer.