Anharmonicity in multifrequency atomic force microscopy

TL;DR

This paper investigates how anharmonicity in multifrequency atomic force microscopy influences experimental observables and theoretical expressions, highlighting the importance of cantilever behavior when multiple frequencies are externally excited.

Contribution

It provides a detailed analysis of cantilever anharmonicity effects on observables and fundamental expressions in multifrequency AFM, emphasizing the control and implications of anharmonicity.

Findings

Cantilever anharmonicity affects monitored amplitudes and phases.

Anharmonicity influences virial and energy transfer expressions.

External excitation of multiple frequencies introduces subharmonic and superharmonic components.

Abstract

In multifrequency atomic force microscopy higher eigenmodes are externally excited to enhance resolution and contrast while simultaneously increasing the number of experimental observables with the use of gentle forces. Here, the implications of externally exciting multiple frequencies are discussed in terms of cantilever anharmonicity, fundamental period and the onset of subharmonic and superharmonic components. Cantilever anharmonicity is shown to affect and control both the observables, that is, the monitored amplitudes and phases, and the main expressions quantified via these observables, that is, the virial and energy transfer expressions which form the basis of the theory.