Ferroelectric Topological Structures: From Discovery to Functional Manipulation

Abstract The introduction of topology has opened up a whole new way of looking at complex ordered states in condensed matter. Ferroelectrics, with their spontaneous polarization as the order parameter, can, under specific boundary conditions, form nontrivial polar textures, especially the polar topological structures (the electric counterparts of the topological spin structures), including flux-closures, vortices, skyrmions, merons, and even hopfions. These polar topological textures come with intriguing functionalities like negative capacitance and chiral optical responses, making them promising building blocks for next generation high density storage and neuromorphic computing. In this review, we trace the evolution of polar topological textures in ferroelectrics from the early experimental breakthroughs to the emergence of diverse material platforms. We examine the design strategies for hosting topological states in different material systems, the stabilization mechanisms behind them, their physical characteristics, and their manipulation by external fields. We then conclude with a perspective on the future trajectory of this rapidly evolving field.