Sub-Angstrom oscillation amplitude non-contact atomic force microscopy for lateral force gradient measurement

Noncontact Atomic Force Microscopy for Atomic-Scale Characterization of Material Surfaces

“…In contrast, since NC-AFM based force spectroscopy experiments typically probe the attractive interaction regime, direct conclusions regarding processes occurring during actual sliding events between two surfaces in contact (i.e., in the repulsive regime) cannot be made in a straightforward fashion. Still, NC-AFM has been used in the past to either directly probe frequency shifts caused by lateral forces by oscillating the tip parallel to the sample surface [243][244][245] or to perform two-or three-dimensional spectroscopy and then take the derivative of the resulting interaction energy field in the lateral directions x and/or y to obtain the lateral force field [81,82,87,240,246]. Moreover, in a powerful demonstration of the technique, Ternes et al used a similar approach to calculate the magnitude of lateral forces needed for lateral manipulation of atoms and molecules on a metal surface [247].…”