Suppression of Octahedral Tilts and Associated Changes of Electronic Properties at Epitaxial Oxide Heterostructure Interfaces

TL;DR

This study uses advanced microscopy techniques to map lattice and octahedral tilt changes at oxide interfaces, revealing a phase transition and electronic property modifications crucial for designing novel oxide heterostructures.

Contribution

It provides the first quantitative, unit-cell-level mapping of lattice parameters and octahedral rotations across oxide interfaces, linking structural changes to electronic properties.

Findings

Identification of a mesoscopic antiferrodistortive phase transition.

Observation of changes in electronic properties near the interface.

Quantitative mapping of lattice and octahedral tilt variations.

Abstract

Epitaxial oxide interfaces with broken translational symmetry have emerged as a central paradigm behind the novel behaviors of oxide superlattices. Here, we use scanning transmission electron microscopy to demonstrate a direct, quantitative unit-cell-by-unit-cell mapping of lattice parameters and oxygen octahedral rotations across the BiFeO3-La0.7Sr0.3MnO3 interface to elucidate how the change of crystal symmetry is accommodated. Combined with low-loss electron energy loss spectroscopy imaging, we demonstrate a mesoscopic antiferrodistortive phase transition and elucidate associated changes in electronic properties in a thin layer directly adjacent to the interface.