Polar Bobbers in Oxide Superlattice

The creation and manipulation of polar topological states in ferroelectric heterostructures have attracted significant attention due to their exotic properties, rich physical insights, and great potential applications in next-generation nanoelectronic devices. A variety of thermodynamically stable polar topologies in ferroelectric superlattice films have been achieved through the precise regulation of strain and electrostatic boundary conditions. Here, we present a novel way for generating a unique metastable phase, termed polar bobbers, through the dynamic application of an external electric field using in situ spherical aberration-corrected transmission electron microscopy. The electric-dipole distribution and stabilization mechanism of these polar bobbers were elucidated at an atomic scale through a combination of electron energy loss spectroscopy and phase-field simulations. It is hoped that a detailed understanding of polar bobbers and their phase-transition behavior will inspire further research into binary data storage devices.