Unusual vortex structure in ultrathin Pb(Zr$_{0.5}$Ti$_{0.5}$)O$_3$ films

TL;DR

This study uses first-principles methods to reveal vortex stripe structures in ultrathin PbZr$_{0.5}$Ti$_{0.5}$O$_3$ films, showing how external fields can manipulate nanodomains for potential applications.

Contribution

It uncovers vortex stripe formations in ultrathin ferroelectric films and demonstrates how external fields can transform these into vortex loops, enabling domain control.

Findings

Vortex stripes are responsible for 180° domains.

External fields can convert vortex stripes into vortex loops.

Vortex manipulation enables nanodomain control.

Abstract

Using a first-principles-based approach, we determine the ferroelectric pattern in PbZr$_{0.5}$Ti$_{0.5}$O$_3$ ultrathin film. It is found that vortex stripes are formed in the system and they are responsible for the 180$^\circ$ domains observed. When a local external field is exerted, the vortex stripe transforms into the vortex loop structure, which leads to the formation of a smaller domain with the polarization antiparallel to the field in the center of the field region. This may provide a convenient way to manipulate nanodomains in thin films.