Electric field driven evolution of topological domain structure in hexagonal manganites

Abstract

Controlling and manipulating the topological state represents an important topic in condensed matters for both fundamental researches and applications. In this work, we focus on the evolution of a real-space topological domain structure in hexagonal manganites driven by electric field, using the analytical and numerical calculations based on the Ginzburg-Landau theory. It is revealed that the electric field drives a transition of the topological domain structure from the type-I pattern to the type-II one. In particular, it is identified that a high electric field can enforce the two antiphase-plus-ferroelectric ($\mathrm{AP}+\mathrm{FE}$) domain walls with $\mathrm{\ensuremath{\Delta}}\mathrm{\ensuremath{\Phi}}=\ensuremath{\pi}/3$ to approach each other and to merge into one domain wall with $\mathrm{\ensuremath{\Delta}}\mathrm{\ensuremath{\Phi}}=2\ensuremath{\pi}/3$ eventually if the electric field is sufficiently high, where $\mathrm{\ensuremath{\Delta}}\mathrm{\ensuremath{\Phi}}$ is the difference in the trimerization phase between two neighboring domains. Our simulations also reveal that the vortex cores of the topological structure can be disabled at a sufficiently high critical electric field by suppressing the structural trimerization therein, beyond which the vortex core region is replaced by a single ferroelectric domain without structural trimerization ($Q=0$). Our results provide a stimulating reference for understanding the manipulation of real-space topological domain structure in hexagonal manganites.