Rotational polarization nanotopologies in BaTiO3/SrTiO3 superlattices

TL;DR

This study reports the discovery of rotational polarization topologies at the nanoscale in BaTiO3/SrTiO3 superlattices, revealing new ferroelectric domain configurations with potential technological implications.

Contribution

It demonstrates the formation of rotational nanodomains in ferroelectric superlattices by controlling the superlattice period, a novel observation at the nanoscale.

Findings

Rotational polarization nanodomains observed in BaTiO3/SrTiO3 superlattices.

Transition from homogeneous to rotational domain states by adjusting superlattice period.

Nominal tetragonal BaTiO3 can host rotational polar textures.

Abstract

Ferroelectrics are characterized by domain structures as are other ferroics. At the nanoscale though, ferroelectrics may exhibit non-trivial or exotic polarization configurations under proper electrostatic and elastic conditions. These polar states may possess emerging properties not present in the bulk compounds and are promising for technological applications. Here, the observation of rotational polarization topologies at the nanoscale by means of aberration-corrected scanning transmission electron microscopy is reported in BaTiO3/SrTiO3 superlattices grown on cubic SrTiO3(001). The transition from a highly homogeneous polarization state to the formation of rotational nanodomains has been achieved by controlling the superlattice period while maintaining compressive clamping of the superlattice to the cubic SrTiO3 substrate. The nanodomains revealed in BaTiO3 prove that its nominal tetragonal structure also allows rotational polar textures.