Electronic structure at the C$_{60}$/metal interface: An angle-resolved photoemission and first-principles study
A. Tamai, A. P. Seitsonen, F. Baumberger, M. Hengsberger, Z.-X. Shen, T. Greber, and J. Osterwalder

High resolution angle--resolved photoemission reveals a complex electronic structure at the interface between a highly ordered C$_{60}${} monolayer and the Cu(111) surface. The Shockley type surface state of the clean substrate is pushed to higher energies by the overlayer and strongly couples to intra-molecular C$_{60}${} phonons. A second interface state with a band width spanning the entire HOMO-LUMO gap disperses with the periodicity of the C$_{60}${} superstructure. Density functional theory calculations indicate that the new state is due to strong hybridization of molecular orbitals and substrate electronic states at the C$_{60}${}/metal interface. This finding sheds new light on the issue of self-doping in molecular layers on metal surfaces.

© 2008 The American Physical Society.