Regensburg 2007 – scientific programme
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O: Fachverband Oberflächenphysik
O 58: Metal Substrates: Adsorption IV
O 58.5: Talk
Thursday, March 29, 2007, 16:45–17:00, H39
Interface characterization of TTF-TCNQ on metal surfaces — •Isabel Fernandez-Torrente1, Sergio Monturet2, Katharina Jennifer Franke1, Nils Henningsen1, Nicolás Lorente2, Jordi Fraxedas3, and José Pascual1 — 1Institut für Experimentalphysik, Freie Universität Berlin, Germany — 2Université Paul Sabatier, Toulouse, France — 3ICMAB, Campus UAB, Bellatera, Spain
Molecular charge transfer (CT) complexes are defined as the association of donor and acceptor molecules. The self-assembling properties of molecules open the possibility of building different donor-acceptor stacking structures which rule the electronic funcionality of the compound. Tetrathiafulvalene 7,7,8,8-tetracyanoquinodimethane (TTF-TCNQ) is an example of a CT complex which shows a metal conducting behaviour. The stacking of TTF and TCNQ forms in bulk one-dimensional partially occupied energy bands that gives rise to the metalicity. By means of Low Temperature Scanning Tunneling Microscopy/Spectroscopy we have characterised for the first time the mixed growth of TTF and TCNQ on a metallic surface in submonolayer and monolayer regimes. The self-assembled growth is governed by donor-acceptor recognition. In particular a one dimensional phase with alternating lines of TTF and TCNQ is formed and can be considered as the precursor stage for the bulk structure. By Scanning Tunneling Spectroscopy we associate electronic resonances with the Highest Occupied Molecular Orbital (HOMO) and the Lowest Unoccupied Molecular Orbital (LUMO) of TTF and TCNQ and the self-assembled TTF-TCNQ.