Vortex-to-Polarization Phase Transformation Path in Pb(ZrTi)O$_3$ Nanoparticles

TL;DR

This study uses first-principles simulations to reveal a unique vortex-to-polarization phase transformation in Pb(ZrTi)O$_3$ nanoparticles, highlighting a novel macroscopic path and microscopic annihilation process under electric fields.

Contribution

It uncovers a previously unknown bridging phase and details the microscopic mechanism of vortex annihilation in ferroelectric nanoparticles.

Findings

Discovery of a new bridging phase during transformation

Identification of a symmetry non-conforming transformation path

Microscopic insight into vortex annihilation process

Abstract

Phase transformation in finite-size ferroelectrics is of fundamental relevance for understanding collective behaviors and balance of competing interactions in low-dimensional systems. We report a first-principles effective Hamiltonian study of vortex-to-polarization transformation in Pb(Zr$_{0.5}$Ti$_{0.5}$)O$_3$ nanoparticles, caused by homogeneous electric fields normal to the vortex plane. The transformation is shown to (1) follow an unusual {\it macroscopic} path that is symmetry non-conforming and characterized by the occurrence of a previously unknown structure as the bridging phase; (2) lead to the discovery of a striking collective phenomenon, revealing how ferroelectric vortex is annihilated {\it microscopically}. Interactions underlying these behaviors are discussed.