Dynamic Manipulation of Ferroelectric Structures via Automated Piezoresponse Force Microscopy*

Ferroelectric domain walls and other topological defects underpin a broad range of applications ranging from domain wall electronics to nonlinear optics. Moreover, exploring their functionalities is of interest to a broad spectrum of applications. However, the dynamic nature of these objects severely constrains piezoresponse force microscopy approaches to explore their functionality. Here, to overcome this challenge, we introduce two examples of automated experiments in piezoresponse force microscopy. First, a real-time piezoresponse force microscopy feedback approach is utilized to control the scanning probe bias during imaging allowing for modification of the domain structures triggered by detected states under the tip. Specifically, the complex trigger system (i.e., “FerroBot”) is used study metastable and frustrated domain-wall dynamics in a Pb_xSr_(1-x)TiO₃ system. We have demonstrated that frustrated phases with enhanced electromechanical response can be created using this technique. Further, we have identified a metastable mechanism of the domain-wall dynamics in this system, i.e., domain-wall bending can be separated from irreversible domain reconfiguration regimes. In conjunction, phase-field modeling was used to corroborate the observed mechanisms. Secondly, we introduce computer vision-based automated experiments to explore the ferroelectric switching behavior of elongated domains in BiFeO₃ thin films. These studies highlight a new pathway towards the discovery and control of metastable states in ferroelectrics, and more generally paves way for automated systems for controlled modification of domain walls and defects to improve material properties.