Aspects of dynamic force microscopy on NaCl/Cu(111): resolution, tip-sample interactions and cantilever oscillation characteristics

Ultrathin films of NaCl on Cu(111) have been studied using a dynamic force microscope. We present images with atomic resolution at step sites on the NaCl films. Force spectroscopy measurements of the tip–sample interaction on NaCl-covered areas and the Cu substrate are analysed with respect to electrostatic, van der Waals and short-range contributions. The interaction contrast between NaCl and Cu is shown to be reflected in the oscillation characteristics of the cantilever. First results of a resonance analysis with the help of a novel digital oscillation control system are presented.