Regensburg 2013 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 66: Oxide Surfaces II
O 66.5: Vortrag
Donnerstag, 14. März 2013, 11:30–11:45, H42
Co-Salen on NaCl(001) and NiO(001): Substrate influence on adsorption geometry and growth — •Josef Grenz1, Alexander Schwarz1, David Gao2, Matthew Watkins2, Alexander Shluger2, and Roland Wiesendanger1 — 1Inst. of Ap. Phy., University of Hamburg, Germany — 2University College London, UK
By depositing the same molecule, i.e., Co-Salen, on two chemically different substrates, i.e., NaCl(001) and NiO(001), with the same surface structure disparities as well as equalities regarding adsorption geometry and growth were investigated.
Since these materials are bulk insulaters, atomic force microscopy in the non-contact mode operated was applied to simulataneously resolve the atomic structure of the surface and to image individual molecules. On both ionic substrates the molecule adsorbs on top of the anions, i.e., chlorine and oxygen. However, on NaCl(001) 16 stable orienations are observed [1], while only 8 are present on NiO(001). Moreover, tip-induced translational motion of individual Co-Salen molecules occur along preferred crystallographic directions and coincide with stable orientations of the molecule on the respective substrate. Tip-induced motions are more frequent on NaCl(001) than on NiO(001), indicating a larger binding energy on the latter. This presumption is supported by the initial layer-by-layer growth observed on NiO(001), while island growth is observed on NaCl(001) [2]. All these experimental findings are in agreement with density functional theory (DFT) calculations.
[1] K. Lämmle, et al., Nano Lett. 10, 2965-2971 (2010).
[2] S. Fremy, et al., Nanotechnology 20, 405608 (2009).