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O: Oberflächenphysik

O 27: Scanning probe techniques II

O 27.6: Vortrag

Dienstag, 28. März 2006, 17:00–17:15, WIL B321

Site-Specific Dynamic Force Spectroscopy on NaCl — •Andre Schirmeisen, Domenique Weiner, and Harald Fuchs — Institute of Physics and CeNTech, University of Münster, Wilhelm-Klemm-Str.10, 48149 Münster, Germany

Dynamic force microscopy under ultrahigh vacuum conditions is an established tool to obtain atomically resolved images of flat surfaces. Recent advances in the technique as well as the interpretation of the underlying physical mechanisms has led to the method of dynamic force spectroscopy, which enabled researchers to determine the forces acting between tip and sample. We have measured the frequency shift and the damping curves using non-contact atomic force spectroscopy of an atomically resolved NaCl surface in ultrahigh vacuum at room temperature. Unfortunately, room temperature measurements usually suffer from considerable temperature drift effects, thus making reliable site-specific force spectroscopy a difficult task. Combining fast data acquisition with a site-averaging technique we obtained reproducible spectroscopy curves. From these spectroscopy curves we calculate the force and the energy dissipation and find that both channels depend strongly on the specific lattice sites. Furthermore, we have investigated the influence of atomic surface defects on the spectroscopy curves.