title: Electronic structure of C60 on Au(887).
abstract: We present an analysis of the electronic structure of C60 adsorbed on a vicinal Au(111) surface at different fullerene coverages using photoemission, x-ray absorption, and scanning tunneling microscopy/spectroscopy (STS). STS provides a straightforward determination of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) levels with respect to the Fermi energy. At C60 coverages of 0.5 and 1 ML a 2.7 eV wide HOMO-LUMO gap is found. The near-edge x-ray absorption fine structure (NEXAFS) spectrum for the 0.5 ML C60 nanomesh structure displays a significant intensity at the low energy side of the LUMO exciton peak, which is explained as due to absorption into HOMO-LUMO gap states localized at individual C60 cluster edges. From 0.5 to 1 ML we observe a rigid shift of the HOMO-LUMO peaks in the STS spectra and an almost complete quenching of the gap states feature in NEXAFS.
authors.affiliation: Donostia International Physics Center, Paseo Manuel Lardizabal 4, E-20018 Donostia-San Sebastián, Spain. schiller@sc.ehu.es
authors.forename: F
authors.initials: F
authors.lastname: Schiller
authors.forename: M
authors.initials: M
authors.lastname: Ruiz-Osés
authors.forename: J E
authors.initials: JE
authors.lastname: Ortega
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authors.initials: P
authors.lastname: Segovia
authors.forename: J
authors.initials: J
authors.lastname: Martínez-Blanco
authors.forename: B P
authors.initials: BP
authors.lastname: Doyle
authors.forename: V
authors.initials: V
authors.lastname: Pérez-Dieste
authors.forename: J
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authors.lastname: Lobo
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authors.lastname: Néel
authors.forename: R
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authors.lastname: Berndt
authors.forename: J
authors.initials: J
authors.lastname: Kröger