Regensburg 2019 – wissenschaftliches Programm
O 3.2: Vortrag
Montag, 1. April 2019, 10:45–11:00, H5
Lateral manipulation of single iron adatoms by combined atomic force and scanning tunneling microscopy using CO-terminated tips — •Julian Berwanger, Ferdinand Huber, Fabian Stilp, and Franz J. Giessibl — University of Regensburg, 93040 Regensburg, Germany
The functionalization of scanning probe microscope (SPM) tips with a CO molecule is widely used due to their outstanding resolution capability on molecules, metal clusters and other sample systems [1-3]. However, the feasibility of CO tips for an extension of imaging by SPM to controlled atomic manipulation  has not been demonstrated. Here, we perform lateral manipulation of single atoms with metal and CO tips. We first study the manipulation characteristics of single atom metal tips and find that asymmetric tips, i.e. tips with a front atom that sits on a tilted atomic tip plane, yield an asymmetry in the lateral force field. When attaching a CO molecule to these tips, their asymmetric force field appears inverted with respect to the underlying tilted metal tips. By applying an analytical model, we propose that the electrostatic interaction is responsible for this inversion of the asymmetry of the lateral force field . Finally we also demonstrate that CO tips can be used to reliably build up large iron clusters atom by atom starting from individual iron atoms.
 L. Gross et al. Science 325, 110 (2009);  M. Emmrich et al. Science 348, 6232 (2015);  M. Ellner et al. Nano Lett. 16, 3 (2016);  D. M. Eigler et al., Nature 344, 524 (1990);  J. Berwanger et al. PRB 98, 195409 (2018)