Non-piezoelectric effects in piezoresponse force microscopy

TL;DR

This paper reviews non-piezoelectric effects like electrostatic and electrochemical influences that can distort PFM measurements, providing guidelines for accurate interpretation of nanoscale ferroelectric phenomena.

Contribution

It systematically summarizes non-piezoelectric origins of PFM signals and offers strategies to distinguish true piezoelectric responses from artifacts.

Findings

Electrostatic effects can mimic piezoelectric signals.

Electrochemical strain contributes to EM response.

Guidelines for proper PFM data interpretation.

Abstract

Piezoresponse force microscopy (PFM) has been used extensively for exploring nanoscale ferro/piezoelectric phenomena over the past two decades. The imaging mechanism of PFM is based on the detection of the electromechanical (EM) response induced by the inverse piezoelectric effect through the cantilever dynamics of an atomic force microscopy. However, several non-piezoelectric effects can induce additional contributions to the EM response, which often lead to a misinterpretation of the measured PFM response. This review aims to summarize the non-piezoelectric origins of the EM response that impair the interpretation of PFM measurements. We primarily discuss two major non-piezoelectric origins, namely, the electrostatic effect and electrochemical strain. Several approaches for differentiating the ferroelectric contribution from the EM response are also discussed. The review suggests a undamental guideline for the proper utilization of the PFM technique, as well as for achieving a reasonable interpretation of observed PFM responses.