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O: Fachverband Oberflächenphysik

O 53: Scanning Probe Methods II

O 53.10: Vortrag

Mittwoch, 13. März 2013, 18:15–18:30, H31

Probing the probe: tip front atom characterization — •Florian Pielmeier and Franz J. Giessibl — Institut für experimentelle und angewandte Physik, Universität Regensburg

The angular dependence of the chemical bonding forces between a tungsten (W) tip and a carbon monoxide molecule adsorbed on Cu(111) has been demonstrated recently by means of atomic force microscopy [1]. Single , dual or tiple minima in the force profile for W tips have been observed. They originate from the different charge density distributions at the apex of the tungsten tip, resembling the high symmetry directions of the bcc crystal lattice [2]. Furthermore absolute values for the interaction forces can be given by 3D force spectroscopy [3]. Here we present data for different tip materials (iron, copper and tungsten), analyzing the different symmetries and forces allows then the identification of the foremost tip atom. This enables a detailed interpretation of experimental data. As the characterization experiment itself is rather straightforward, this method, called carbon monoxide front atom identification (COFI), can be used in general to characterize the probe prior and/or after any experiment.

[1] J. Welker, F.J. Giessibl, Science, 336, 444 (2012) [2] C. A. Wright, S. D. Solares, Nanoletters, 11, 5026 (2011) [3] H. Hölscher, S.M. Langkat, A. Schwarz, R. Wiesendanger, Applied Physics Letters, 81, 4428 (2002)