ABSTRACT Creation and manipulation of polar nanostructures in ferroelectrics remains a central challenge toward their electronic and non‐linear optical applications. Here, using high‐resolution scanning probe and transmission electron microscopy, the electric field‐induced creation of stable nanoscale bubble domains, confined to the surface of lead magnesium niobate–lead titanate single crystals, is demonstrated. The polarization orientation of the nanoscale bubbles is anti‐aligned to the poling electric field and to the switched polarization in the crystal's bulk. Interestingly, under above‐bandgap illumination, these nanoscale domains show little to no change; however, as soon as the illumination is turned off, these nanodomains rapidly expand to switch the entire crystal's surface, and eventually relax back. Time‐resolved Kelvin probe force microscopy reveals a pronounced surface potential jump of up to ≈ −5 V upon illumination cessation, suggesting a large reservoir of electrons on the crystal surface. These observations support a post‐illumination anomalous switching governed by an interplay of negatively charged tail‐to‐tail bubble domain walls, depolarization fields, and the bulk photovoltaic effect. Our results establish a new pathway for creating and optically controlling bubble domains in relaxor ferroelectrics, opening opportunities for emergent optoferroic functionalities.
Zhang et al. (Mon,) studied this question.