Experimental reconstruction of the contact resonance shape factor for quantification and amplification of bias-induced strain in atomic force microscopy

The contact resonance (CR) of a surface coupled atomic force microscope (AFM) cantilever can act as an amplifier of AC surface motion for piezoresponse force microscopy and related methods. However, the amplifier properties of the CR vary depending on tip-sample boundary conditions, leading to the appearance of displacement amplitude contrast when only stiffness contrast exists. It was recently proposed that the shape of the vibrating cantilever as a function of CR frequency could be analytically modeled and a shape factor calibration could be applied. Here, we demonstrate an experimental reconstruction of the contact resonance shape factor that can be used to quantify surface displacements in AFM measurements, without reliance on analytical models with uncertain input parameters. We demonstrate accurate quantification of surface displacement in periodically poled lithium niobate and pave the way for quantification of extremely small surface strains in the future.The contact resonance (CR) of a surface coupled atomic force microscope (AFM) cantilever can act as an amplifier of AC surface motion for piezoresponse force microscopy and related methods. However, the amplifier properties of the CR vary depending on tip-sample boundary conditions, leading to the appearance of displacement amplitude contrast when only stiffness contrast exists. It was recently proposed that the shape of the vibrating cantilever as a function of CR frequency could be analytically modeled and a shape factor calibration could be applied. Here, we demonstrate an experimental reconstruction of the contact resonance shape factor that can be used to quantify surface displacements in AFM measurements, without reliance on analytical models with uncertain input parameters. We demonstrate accurate quantification of surface displacement in periodically poled lithium niobate and pave the way for quantification of extremely small surface strains in the future.