Abstract: Phys. Rev. Lett. 80 (1998) 4269-4272

W. Widdra, A. Fink, S. Gokhale, P. Trischberger, D. Menzel, U. Birkenheuer, U. Gutdeutsch, and N. Rösch
One-Dimensional Delocalized Adsorbate Bloch States on a Semiconductor Surface: C2H4/Si(001)-(2x1)
Phys. Rev. Lett. 80 (1998) 4269-4272.
[May. 11, 1998]


We report the observation of a 1D molecular adsorbate band structure caused by direct adsorbate-adsorbate interactions on a semiconductor. For ethylene chemisorbed on Si(001)-(2 x 1) two adsorbate-derived electronic states, 1b(3u) and 1b(2g), are found to delocalize along the Si-Si dimer rows. The corresponding bands can be followed in reciprocal space from the <(Gamma)over bar> point into the third surface Brillouin zone. Density functional calculations for ethylene adsorbed on a silicon slab reproduce the experimental 1D band structure and allow us to identify the origin of the lateral interactions.