Study of Antiferroelectric Domain Structures and Switching Behaviors of Epitaxial PbZrO₃ films

Antiferroelectrics (AFE) possess high charge storage density and working efficiency, which show great potential for energy-storage applications. The functional characteristics of antiferroelectrics can be revealed from the tri-stable polarization states under the electrical switching process. Despite its importance in determining AFE orderings at nanoscale, nondestructive detections of AFE domains are rarely discussed due to their zero remnant polarization. In this study, we investigate the local polarization switching and antiferroelectric-ferroelectric transition of PbZrO3 (PZO) epitaxial thin film grown on SrTiO3 through switching spectroscopy piezoresponse force microscopy (SS-PFM). Mechanisms other than antiferroelectricity, such as charge injection, migration of oxygen vacancies, etc., are easily induced at high electric fields and cover the contribution of antiferroelectricity in electromechanical signals. To solve this, we use unsupervised machine-learning techniques to analyze the data and separate the characteristics of different mechanisms. The models of contributed mechanisms are also discussed. This approach enables the visualization of AFE domain structures and can be used to realize the polarization transition process in antiferroelectrics.