Dynamic Behavior in Piezoresponse Force Microscopy

TL;DR

This paper analyzes the frequency-dependent dynamic behavior in Piezoresponse Force Microscopy through modeling and experiments, identifying how various forces and parameters influence the signals and proposing conditions for optimal imaging.

Contribution

It introduces a combined modeling and experimental approach to understand dynamic PFM signals, highlighting the roles of electrostatic and electromechanical interactions and their dependence on system parameters.

Findings

Identified contributions of electrostatic and electromechanical forces to PFM signals.

Developed conditions for optimal PFM imaging based on dynamic analysis.

Implemented frequency-bias spectroscopy for probing cantilever dynamics.

Abstract

Frequency dependent dynamic behavior in Piezoresponse Force Microscopy (PFM) implemented on a beam-deflection atomic force microscope (AFM) is analyzed using a combination of modeling and experimental measurements. The PFM signal comprises contributions from local electrostatic forces acting on the tip, distributed forces acting on the cantilever, and three components of the electromechanical response vector. These interactions result in the bending and torsion of the cantilever, detected as vertical and lateral PFM signals. The relative magnitudes of these contributions depend on geometric parameters of the system, the stiffness and frictional forces of tip-surface junction, and operation frequencies. The dynamic signal formation mechanism in PFM is analyzed and conditions for optimal PFM imaging are formulated. The experimental approach for probing cantilever dynamics using frequency-bias spectroscopy and deconvolution of electromechanical and electrostatic contrast is implemented.