Berlin 2015 – scientific programme
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O: Fachverband Oberflächenphysik
O 89: Inorganic/Organic Interfaces: Molecular Switches
O 89.10: Talk
Thursday, March 19, 2015, 17:15–17:30, MA 043
Switching Orientation of adsorbed Molecules: Reverse Domino on a Metal Surface — •Taner Esat1,2, Carolin R. Braatz3, Christian Wagner1,2, Ruslan Temirov1,2, F. Stefan Tautz1,2, and Peter Jakob3 — 1Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, Germany — 2JARA-Fundamentals of Future Information Technology — 3Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität Marburg, 35032 Marburg, Germany
In a two-pronged approach, using infrared absorption spectroscopy and scanning tunneling microscopy, a thus far unknown monolayer phase of 1,4,5,8-naphthalene-tetracarboxylic dianhydride (NTCDA) on Ag(111), characterized by an all perpendicular orientation of the planar molecules has been identified. This conclusion is based on a quantitative analysis of characteristic vibrational modes with specific polarizations, as well as STM images of the standing NTCDA molecules. Formation of the vertically standing NTCDA phase requires second layer NTCDA to squeeze into empty spaces between relaxed monolayer NTCDA molecules. This process causes initially parallel oriented NTCDA to likewise adopt the inclined adsorption geometry. The new phase shows a pronounced tendency to form 1D rows or narrow islands. We suggest that extra NTCDA preferentially transforms into the upright configuration next to existing islands, i.e. the transformation process proceeds in a directed and recurrent manner (reversed domino effect). We also present revised structure models for the relaxed and the compressed NTCDA/Ag(111) monolayer phases.