Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 15: STM/AFM: New Approaches
O 15.3: Vortrag
Montag, 7. März 2016, 15:30–15:45, H24
Atomic force microscopy reveals the structure of its tip and subatomic resolution on single iron adatoms — Matthias Emmrich1, •Ferdinand Huber1, Florian Pielmeier1, Joachim Welker1, Thomas Hofmann1, Maximilian Schneiderbauer1, Daniel Meuer1, Svitlana Poleysa2, Sergiy Mankovsky2, Diemo Ködderitzsch2, Hubert Ebert2, and Franz J. Giessibl1 — 1Institute of Experimental and Applied Physics, Department of Physics, University of Regensburg, 93053 Regensburg, Germany — 2Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstraße 11, 81377 München, Germany
A CO molecule adsorbed on a Cu(111) surface can be used to probe the apex of an atomic force microscopy (AFM) tip [1]. In our recent work [2], we invert our previous experiment [1] and functionalize our tip with a CO molecule [3] to investigate single adatoms and clusters built from individual iron atoms adsorbed on a Cu(111) surface. Our findings correct our previous interpretation [1] and suggest that dual and triple minima in the force signal are caused by dimer and trimer tips, respectively [2]. However, we show subatomic resolution AFM: single iron adatoms do not appear as a single depression or protrusion, but as a toroidal structure. Its shape reflects the bonding symmetry of the adatom to the underlying substrate. Density functional theory (DFT) calculations support the experimental data.
[1] J. Welker and F. J. Giessibl, Science 336, 444 (2012)
[2] M. Emmrich, F. Huber et al., Science 348, 308 (2015)
[3] L. Gross et al., Science 325, 1110 (2009)