Substrate coherency-driven octahedral rotations in perovskite oxide films

TL;DR

This study uses first-principles calculations to investigate how substrate-induced octahedral rotations influence the structure of perovskite oxide films, revealing potential for electronic property tuning.

Contribution

It demonstrates that substrate coherency can induce unique octahedral rotation patterns in oxide films, offering a new method for manipulating their electronic structures.

Findings

Substrate rotation patterns often propagate into the film.

Certain elastic boundary conditions induce novel atomic displacements.

Substrate coherency can be used to tune electronic properties.

Abstract

We perform first-principles density functional calculations to explore the role of substrate proximity effects on the octahedral rotation patterns in perovskite oxide superlattices. With cubic perovskite SrFeO$_3$ as our model film and tetragonal SrTiO$_3$ as the substrate, we show that in most cases the substrate octahedral rotation patterns propagate into the film across the heterointerface. We also identify elastic boundary conditions for which the enforced structural coherence induces atomic displacement patterns that are not found in the bulk phase diagram of either individual constituent. We suggest that such substrate coherency-induced octahedral texturing of thin film oxides is a promising approach for tuning the electronic structure of functional oxide thin films.