Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 63: Scanning Probe Microscopy and Spin Phenomena
O 63.5: Vortrag
Mittwoch, 9. März 2016, 16:45–17:00, H4
DFT Simulation of AFM-images of Fe, Cu and Si adatoms on Cu(111): different tip models — •Svitlana Polesya1, Sergiy Mankovskyy1, Hubert Ebert1, and Franz Giessibl2 — 1Universität München, Department Chemie, Butenandtstr. 5-13, D-81377 München, Germany — 2Institut für Experimentelle Phzsik, Univ. Regensburg, Germany
Atomic Force Microscopy (AFM) images for Fe, Cu and Si adatoms in there equilibrium positions on Cu(111) surface have been simulated on the basis of Density Functional Theory (DFT). We focus in the present work on the effect of different types of tips on the AFM image. For that reason, the forces experienced by the tip have been calculated for three tip models: single H atom, CO molecule and Cu4 cluster. The calculated forces for the CO molecule tip fully reproduce the experimentally observed distance dependence of the force profile for a Cu adatom. Also the three fold symmetry of the lateral AFM-image for a Fe adatom, in contrast to a Cu adatom, can be explained using the results of the calculations. The nature of the repulsive forces at large lateral distances from the adatom position (∼ 200-250 pm) is discussed on the basis of the electron density redistribution in the tip-adatom region.