Control of the structural and magnetic properties of perovskite oxide ultrathin films through the substrate symmetry effect

TL;DR

This study demonstrates how substrate symmetry mismatch influences the structural and magnetic properties of ultrathin perovskite oxide films by inducing unique interfacial distortions.

Contribution

It reveals that substrate symmetry mismatch creates novel interface properties through induced distortions, independent of chemical effects.

Findings

Interfacial layer with unique distortion modes due to symmetry mismatch

Interface layer size varies with octahedral resistance

Symmetry effects can tailor electronic and magnetic properties

Abstract

Perovskite transition-metal oxides are networks of corner-sharing octahedra whose tilts and distortions are known to affect their electronic and magnetic properties. We report calculations on a model interfacial structure to avoid chemical influences and show that the symmetry mismatch imposes an interfacial layer with distortion modes that do not exist in either bulk material, creating new interface properties driven by symmetry alone. Depending on the resistance of the octahedra to deformation, the interface layer can be as small as one unit cell or extend deep into the thin film.