Nonlinear dynamics of microcantilevers in tapping mode atomic force microscopy: A comparison between theory and experiment

The nonlinear dynamic response of atomic force microscopy cantilevers tapping on a sample is discussed through theoretical, computational, and experimental analysis. Experimental measurements are presented for the frequency response of a specific microcantilever-sample system to demonstrate the nonlinear features, including multiple jump phenomena leading to reproducible hysteresis. We show that a comprehensive analysis using modern continuation tools for computational nonlinear dynamics and bifurcation problems reproduces all essential features of the data. A close connection is established between the features of the interaction potential well and the nonlinear forced tip response. In particular, the effects of the nonlinear van der Waals forces, the nanoscale contact nonlinearities, and microcantilever damping, as well as the effects of forced and parametric excitation on the bifurcations and instabilities of forced periodic motions of the microcantilever system, are discussed in detail. The results indicate that nonlinear system identification methods could be used as effective tools to extract detailed information about the tip-surface interaction potential.