铁电材料中的极性拓扑结构

调控磁性材料中的自旋拓扑结构(流量闭合型、涡旋、半子(meron)、斯格明子(skyrmion)等自旋组态)可以改进材料的磁性和电磁性能,因而引起了学术界的广泛关注.最近研究表明,在尺寸效应、界面耦合及其相互作用、外延应变等作用下,铁电材料中也会出现自发的极性拓扑畴结构,同时表现出新的铁电相结构和丰富的物理性能.本文总结了铁电纳米结构、铁电薄膜和铁电超晶格中的极性拓扑畴结构类型及其形成机理,分析了这些极性拓扑结构与铁电、压电、介电、光电性能之间的关联,并分别讨论了铁电材料中极性拓扑结构的整体拓扑相变调控和单个极性拓扑结构的外场调控,最后展望了极性拓扑结构未来的可能研究方向.

Polar topological structures in ferroelectric materials

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.