Dresden 2011 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 36: Poster Session II (Metals; Nanostructures at surfaces; Surface or interface magnetism; Spin-Orbit Interaction at Surfaces; Electron and spin dynamics; Surface dynamics; Methods; Theory and computation of electronic structure)

O 36.6: Poster

Dienstag, 15. März 2011, 18:30–22:00, P4

Comparing CuPc and H₂Pc sub-monolayer films on Ag(111): A NIXSW and SPA-LEED study — •Ingo Kröger¹, Patrick Bayersdorfer², Benjamin Stadtmüller¹, Christoph Kleimann¹, Giuseppe Mercurio¹, Friedrich Reinert², and Christian Kumpf¹ — ¹Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany and JARA-Fundamentals of Future Information Technology — ²Experimentelle Physik 7, Universität Würzburg, 97074 Würzburg

The sub-monolayer growth of metal-phthalocyanines (MePc) on the Ag(111) surface exhibits a rich phase diagram consisting of 2D gas-like phases, commensurate phases and - most interestingly - a continuous series of phases with point-on-line coincidence with the substrate [1,2]. The latter is caused by repulsive intermolecular interaction. In order to clarify the role of the central metal atom for this repulsion, we compare SPA-LEED and NIXSW data of the metal free H₂Pc/Ag(111) with CuPc/Ag(111). The similarity of the phase diagrams leads to the conclusion that in principle the intermolecular repulsion does not depend on the metal atom. For H₂Pc the adsorption heights show a significant bending of the nitrogen atoms toward the surface. This "N-down" configuration leads to a stronger and more localized bonding to the surface, and therefore stabilizes the commensurate phase in a wider coverage regime and at higher temperature compared to CuPc/Ag(111). [1] Kröger et al., New Journal of Physics 12, 083038 (2010) [2] Stadler et al., Nature Physics 5, 153 (2009)