Ferroelectricity in artificial bicolor oxide superlattices

TL;DR

This paper demonstrates that artificial bicolor oxide superlattices exhibit enhanced ferroelectric polarization due to interfacial ionic motions, offering a novel approach to engineer ferroelectric properties beyond bulk materials.

Contribution

It introduces high-quality bicolor oxide superlattices with unique structural and ferroelectric properties, highlighting the role of interfacial ionic motions in polarization enhancement.

Findings

Superlattices show higher polarization than bulk equivalents.

Enhanced ionic motions at hetero-interfaces drive ferroelectricity.

Structural uniqueness not achievable in bulk materials.

Abstract

We report on the growth and properties of high quality bicolor oxide superlattices, composed of two perovskites out of BaTiO3, CaTiO3, and SrTiO3. The artificially grown superlattices are structurally unique and have a macroscopically homogeneous phase, which is not feasible to recreate in bulk form. By artificial structuring, it is found that the polarization of such superlattices can be highly increased as compared to pseudo-binary ceramics with the same overall composition. Such strong enhancement in superlattice is attributed to newly-developed ionic motions of A-site cations at the hetero-interfaces due to the interfacial coupling of electrostatic and elastic interactions, which cannot be found in single phase materials.