Higher-eigenmode piezoresponse force microscopy: a path towards increased sensitivity and the elimination of electrostatic artifacts

Piezoresponse forcemicroscopy (PFM) and related bias-induced strain sensing atomic force microscopy techniques provide unique characterization ofmaterial-functionality at the nanoscale. However, these techniques are prone to unwanted artifact signals that influence the vibration amplitude of the detecting cantilever. Here, we show that higher-order contact resonance eigenmodes can be readily excited in PFM.The benefits of using the higher-order eigenmodes include absolute sensitivity enhancement, electrostatic artifact reduction, and lateral versus normal strain decoupling. This approach can significantly increase the proportion of total signal arising fromdesired strain (as opposed to non-strain artifacts) inmeasurements with cantilevers exhibiting typical, fewNm spring constants to cantilevers up to 1000× softer than typically used.