Regensburg 2010 – scientific programme
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O: Fachverband Oberflächenphysik
O 25: Metal substrates: Adsorption of organic / bio molecules III
O 25.2: Talk
Tuesday, March 23, 2010, 10:45–11:00, H36
Positioning Co atoms with organic molecular templates — •Wolfgang Krenner1, Dirk Kühne1, Florian Klappenberger1, Svetlana Klyatskaya2, Mario Ruben2, and Johannes V Barth1 — 1Physikdepartment E20, TU München, München, Germany — 2Institute of Nanotechnology, Forschungszentrum Karlsruhe, Karlsruhe, Germany
In this work the adsorption of atomic Cobalt onto organic molecular templates is investigated by means of low-temperature scanning tunneling microscopy under UHV conditions. When evaporated onto a Ag(111) surface held at room temperature, diphenyl oxalic amides can be grown into strings across the surface at submonolayer coverages or as densely packed monolayers. Co is evaporated at low temperatures around 140 K onto submonolayers and monolayers, displaying different behavior depending on the coverage, which will be discussed.
The presence of the molecular layer prevents the formation of Co-clusters and instead leads to an adsorption of atomic Co onto the phenyl rings of the oxalic amides. Annealing the sample leads to a redistribution of the Co atoms on the monolayer. At coverages well below a single monolayer a bending of the molecular strings in the presence of Co is observed, which is no longer the case for coverages just below a monolayer. Through annealing it is found, that diffusion of Co atoms away from the molecular strings takes place. In both cases it is possible to assemble ordered arrays of single Co atoms sitting on top the phenyl rings of the oxalic amides, therefore forming chains of ferromagnetic atoms.