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O: Fachverband Oberflächenphysik
O 6: Organic/bio Molecules on Metal Surfaces I
O 6.9: Vortrag
Montag, 11. März 2013, 12:30–12:45, H38
Substrate-mediated band-dispersion of adsorbate molecular states — •Michael Wießner1, Peter Puschnig2, Masashi Arita3, Kenya Shimada3, Achim Schöll1, and Friedrich Reinert1 — 1Universität Würzburg, Experimentelle Physik VII, 97074 Würzburg, Germany — 2Institut für Physik, Karl-Franzens Universität Graz, Austria — 3Hiroshima Synchrotron Radiation Center, Hiroshima University, Hiroshima 739-0046, Japan
Charge carrier mobilities in molecular condensates are usually small, since the coherent transport, which is highly effective in conventional semiconductors, is impeded by disorder and the small intermolecular coupling. A significant band dispersion can usually only be observed in exceptional cases such as for π-stacking of aromatic molecules in organic single crystals. Based on angular resolved photoemission, we demonstrate on the example of planar π-conjugated molecules, that the hybridisation with a metal substrate can substantially increase the delocalization of the molecular states in selective directions along the surface. Supported by ab initio calculations we show how this mechanism couples individual 3,4,9,10-perylenetetracarboxylic-dianhydride (PTCDA) molecules via the Ag(110) substrate within the organic layer resulting in a four times larger in-plane charge carrier mobility.