Mode Coupling in Dynamic Atomic Force Microscopy

Journal article (2021)

Authors

A. Chandrashekar Dynamics of Micro and Nano Systems - Mechanical, Maritime and Materials Engineering
P. Belardinelli Università Politecnica delle Marche
Stefano Lenci Università Politecnica delle Marche
U. Staufer Micro and Nano Engineering - Mechanical, Maritime and Materials Engineering
F. Alijani Dynamics of Micro and Nano Systems - Mechanical, Maritime and Materials Engineering
Research Group
Dynamics of Micro and Nano Systems (Mechanical, Maritime and Materials Engineering) (TU Delft)
Copyright: © 2021 A. Chandrashekar, P. Belardinelli, Stefano Lenci, U. Staufer, F. Alijani
DOI
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https://doi.org/10.1103/PhysRevApplied.15.024013
More Info
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Published Date

2021

Language

English

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Faculty

Mechanical, Maritime and Materials Engineering

Department

Precision and Microsystems Engineering

Research Group

Dynamics of Micro and Nano Systems

Abstract

Increasing the signal-to-noise ratio in dynamic atomic force microscopy plays a key role in nanomechanical mapping of materials with atomic resolution. In this work, we develop an experimental procedure for increasing the sensitivity of higher harmonics of an atomic-force-microscope cantilever without modifying the cantilever geometry but instead by utilizing dynamical mode coupling between its flexural modes of vibration. We perform experiments on different cantilevers and samples and observe that via nonlinear resonance frequency tuning we can obtain a frequency range where strong modal interactions lead to 7-fold and 16-fold increases in the sensitivity of the 6th and 17th harmonics while reducing sample indentation. We derive a numerical model that captures the observed physics and confirms that nonlinear mode coupling is the reason for the increase of the amplitude of higher harmonics during tip-sample interactions.