Electric field control of Jahn-Teller distortions in bulk perovskites

TL;DR

This study demonstrates a novel method to control Jahn-Teller distortions in bulk perovskites using electric fields, via anharmonic lattice mode coupling, potentially enabling new electronic functionalities.

Contribution

It introduces a first-principles approach showing electric field control of Jahn-Teller distortions through anharmonic coupling in perovskites, a mechanism previously not exploited.

Findings

Electric field influences Jahn-Teller distortions via anharmonic coupling.

Coupling exists within the P b2 1 m space group under tensile strain.

Mechanism applies broadly, not limited to Jahn-Teller active systems.

Abstract

The Jahn-Teller distortion, by its very nature, is often at the heart of the various electronic properties displayed by perovskites and related materials. Despite the Jahn-Teller mode being non- polar in nature, we devise and demonstrate in the present letter an electric field control of Jahn-Teller distortions in bulk perovskites. The electric field control is enabled through an anharmonic lattice mode coupling between the Jahn-Teller distortion and a polar mode. We confirm this coupling, and explicitly an electric field effect, through first principles calculations. The coupling will always exist within the P b2 1 m space group, which is found to be the favoured ground state for various perovskites under sufficient tensile epitaxial strain. Intriguingly, the calculations reveal that this mechanism is not only restricted to Jahn-Teller active systems, promising a general route to tune or induce novel electronic functionality in perovskites as a whole.