Is atomic-scale dissipation in NC-AFM real? Investigation using virtual atomic force microscopy

摘要

Using a virtual dynamic atomic force microscope, that explicitly simulates the operation of a non- contact AFM experiment, we have performed calculations to investigate the formation of atomic-scale contrast in dissipation images. A non- conservative tip - surface interaction was implemented using the theory of dynamical response in scanning probe microscopy with energies and barriers derived from realistic atomistic modelling. It is shown how contrast in the damping signal is due to the hysteresis in the tip - surface force and not an artefact of the finite response of the complicated instrumentation. Topography and dissipation images of the CaO( 001) surface are produced which show atomic- scale contrast in the dissipation with a corrugation of approximately 0.1 eV, which is typical of that observed in images of similar binary ionic surfaces. The effect of the fast- direction scanning speed on the image formation is also investigated and discussed.