Topological Vortex Domains in Quantum Materials

Abstract:

Engineering of domains and domain boundaries is quintessential for technological exploitation of numerous functional materials. However, it has only recently realized that the configuration of these domains/⁠domain boundaries can have non-⁠trivial topology. We will discuss a new topological classification scheme of domain/⁠domain boundary configurations with Ising-⁠type or two-⁠dimensional order parameters: Zm×Zn domains (m directional variants and n translational antiphases) and Zl vortices (where l number of domains and that of domain boundaries merge). This classification, with the concept of topological protection and topological charge conservation, has been applied to a wide range of materials such as improper ferroelectric R(Mn,Fe)O3, antipolar In(Mn,Ga)O3, hybrid improper ferroelectric (Ca,Sr)3Ti2O7, chiral (and ferromagnetic) Fe1/⁠3TaS2, and magnetic-⁠superconducting Sr2VO3FeAs. We will also discuss the emergent physical properties of domain boundaries, distinct from those of domains. The presented topological consideration provides a basis in understanding the formation, kinetics, manipulation and property optimization of domains/⁠domain boundaries in quantum materials.