Effect of material stiffness on intermodulation response in dynamic atomic force microscopy

TL;DR

This study investigates how surface stiffness influences the intermodulation response of an atomic force microscope cantilever through simulations and experiments, revealing qualitative similarities but quantitative discrepancies due to modeling limitations.

Contribution

It provides new insights into the effect of material stiffness on intermodulation in AFM, combining simulation and experimental approaches.

Findings

Qualitative agreement between simulations and experiments

Surface stiffness significantly affects intermodulation response

Quantitative differences highlight the need for improved force models

Abstract

We perform simulations and experiments on an oscillating atomic force microscope cantilever approaching a surface, where the intermodulation response of the cantilever driven with two pure harmonic tones is investigated. In the simulations, the tip and surface interact with a conservative nonlinear force, and the parameter space of approach distance and surface stiffness is explored. Approach experiments are carried out on three surfaces with widely varying stiffness. Qualitative similarities between simulations and experiment can be seen, but quantitative comparison is difficult due to the overly idealized tip-surface force model used in the simulation.