Higher-harmonics generation in tapping-mode atomic-force microscopy: Insights into the tip-sample interaction

We present an experimental analysis of the nonlinear tip-sample interaction in tapping-mode atomic-force microscopy by exploiting anharmonic contributions of the cantilever motion. Two aspects of a concept aiming at a full reconstruction of the tip-sample interaction are demonstrated: higher flexural eigenmode vibrations excited by the impact of the oscillating tip on the sample are used to measure the tip-sample interaction time: by imaging at higher harmonics of the driving frequency material contrast is obtained. (C) 2000 American Institute of Physics. [S0003-6951(00)03823-7].