Ab initio simulation of atomic-scale imaging in noncontact atomic force microscopy.
In this paper, we summarize some results of our ab initio simulations aimed at investigating the mechanism of the NC-AFM image contrast on semiconductor and metallic surfaces. We start with an introduction into the basic ideas behind the ab initio simulation process of the NC-AFM experimental results. Our simulations reveal that the interaction of a clean silicon tip with a semiconductor surface like InAs(110) might lead to bond-formation and bond-breaking processes during the approach and retraction of the tip. This imaging mechanism is very similar to that observed on a metallic surface like Ag(110). Interestingly, a clean silicon tip can become contaminated with Ag surface atoms. On both types of surface we observe a significant energy dissipation which is caused by a hysteresis in the tip-sample force curves calculated on the approach and retraction path.
Caciuc
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Institut für Festkörperforschung, Theorie I, Foschungszentrum Jülich, Jülich D-52425, Germany. v.caciuc@fz-juelich.de
Hölscher
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