Regensburg 2000 – wissenschaftliches Programm
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O: Oberflächenphysik
O 11: Postersession (Eröffnung)
O 11.51: Poster
Montag, 27. März 2000, 19:00–22:00, Bereich C
Geometrical properties and electronic structure of chlorinated C60 films — •Sebastian Woedtke, Alexander Meeder, Rainer Adelung, Lutz Kipp, and Michael Skibowski — Institut für Experimentelle und Angewandte Physik, Universität Kiel, D-24118 Kiel, Germany
The n-type doping of fullerene films by alkali metals and the formation of superconducting fulleride phases have been widely studied. In view of a possible acceptor p-type doping only halogens exhibit suitable electronegativities which theoretically allow the depletion of the fivefold degenerate highest occupied molecular orbital (HOMO) of C60 whereby chlorine offers the most promising electron affinity. Analogous to alkali doping ultrathin C60 films were exposed to chlorine gas under UHV conditions in order to study their surface properties with STM, photoelectron spectroscopy (UPS/XPS) and x-ray absorption spectroscopy (XANES). The STM measurements reveal a strong halogen-induced influence on the fullerene cluster edges. Photoemission results are evaluated in the framework of a possible covalent or van der Waals-like halogen-fullerene bonding connected with an eventual chlorine intercalation into the interstitial sites of the C60 fcc lattice. Furthermore, charge transfer and screening effects are taken into account in view of possible similarities to the classical alkali doping.