A theoretical analysis of the lateral force as measured with a scanning force microscope is performed, showing that the lateral force signal contains a topography-induced component which is proportional to the slope of the surface, in addition to the signal arising from the tangential force. Measurements carried out on corrugated samples (gold, indium-tin-oxide, diamond) are analysed within the framework of this theory on the basis of a simple physical model for the forces, taking into account a repulsive normal force, a tangential friction force, and an adhesion force. The correlation between the lateral force and the topography is confirmed quantitatively. Furthermore, friction coefficients are determined and the influence of the adhesion force on the data is discussed.
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