Dynamic atomic force microscopy methods
In this report we review the fundamentals, applications and future tendencies of dynamic atomic force
microscopy (AFM) methods. Our focus is on understanding why the changes observed in the dynamic properties
of a vibrating tip that interacts with a surface make possible to obtain molecular resolution images of membrane
proteins in aqueous solutions or to resolve atomic-scale surface defects in ultra high vacuum (UHV). Our
description of the two major dynamic AFM modes, amplitude modulation atomic force microscopy (AM-AFM)
and frequency modulation atomic force microscopy (FM-AFM) emphasises their common points without
ignoring the differences in experimental set-ups and operating conditions. Those differences are introduced by the
different feedback parameters, oscillation amplitude in AM-AFM and frequency shift and excitation amplitude in
FM-AFM, used to track the topography and composition of a surface.