Electrostatic forces acting on tip and cantilever in atomic force microscopy

Abstract

In this paper we quantitatively compare different electrostatic models, which describe the interaction between the tip of an electrically biased atomic force microscopy cantilever and a conducting flat substrate. The models by Hudlet et al. [Eur. Phys. J. B 2, 5 (1998)] and Colchero et al. [Phys. Rev. B 64, 245403 (2001)] provide excellent descriptions of the experimental force, for tip parameters close to their typical values, although an accurate treatment of the electrostatic force contribution due to the cantilever is still missing. We introduce it here, together with a correction function which accounts for the tilting angle between the cantilever and surface, and confirm it with several experiments. Since the electrostatic force acting between a cantilever and a surface can be accurately tuned, force measurements with a defined voltage are also suitable for calibrating cantilever spring constants.