Polar topological structures in ferroelectric materials

Abstract

Spin topologies, including flow-closure, vortex, meron, skyrmion and other spin configurations, are usually found in magnetic materials. The emergence of the topological structures will trigger a number of intriguing functionalities and physical properties. Recent studies have shown that the trival domain structures can be transformed into polar topological domain structures under certain boundary conditions, such as size-confining, interfacial coupling, and epitaxial strain. In this paper, we review the observations of polar topologies and their formation mechanism in ferroelectric nanoparticles, thin films, and superlattice films, and focus on the intriguing properties, including ferroelectric, piezoelectric, dielectric, and photoelectric performances, which arise from the formation of polar topologies. We also review the highlights of recent studies of the manipulations and evolutions of polar topologies under the external field loading in ferroelectric materials. Finally, the future research directions of polar topological structure and potential application directions are proposed.