Smallest 90o domains in epitaxial ferroelectric films

TL;DR

This paper reports the creation of the narrowest 90-degree ferroelectric domains in epitaxial films, achieving 7 nm width while maintaining lateral coherence, advancing nanoscale ferroelectric device potential.

Contribution

It demonstrates the growth of self-patterned 90-degree domains as narrow as 7 nm in epitaxial ferroelectric films, a record for maintaining coherence at this scale.

Findings

Achieved 7 nm wide 90-degree domains

Domains maintain lateral coherence independently of substrate

Advances nanoscale ferroelectric domain control

Abstract

Ferroelectrics display spontaneous and switchable electrical polarization. Until recently, ferroelectricity was believed to disappear at the nanoscale; now, nano-ferroelectrics are being considered in numerous applications. This renewed interest was partly fuelled by the observation of ferroelectric domains in films of a few unit cells thickness, promising further size reduction of ferroelectric devices. It turns out that at reduced scales and dimensionalities the material's properties depend crucially on the intricacies of domain formation, that is, the way the crystal splits into regions with polarization oriented along the different energetically equivalent directions, typically at 180o and 90o from each other. Here we present a step forward in the manipulation and control of ferroelectric domains by the growth of thin films with regular self-patterned arrays of 90o domains only 7 nm wide. This is the narrowest width for 90o domains in epitaxial ferroelectrics that preserves the film lateral coherence, independently of the substrate.