Jahn-Teller distortion and electronic correlation effects in undoped manganese perovskites

TL;DR

This paper investigates how Jahn-Teller distortions and electronic correlations influence the insulating behavior of undoped manganites, highlighting the dominance of electronic repulsion over electron-phonon interactions.

Contribution

It provides a theoretical analysis using dynamical mean-field theory to explain experimental observations in undoped manganites, emphasizing the role of electronic correlations.

Findings

Insulating behavior above Jahn-Teller transition explained by strong electronic repulsion.

Bond-length changes below transition linked to Jahn-Teller distortion.

Weak electron-phonon coupling suffices to account for observed phenomena.

Abstract

The formation of a long-range Jahn-Teller distortion in undoped manganites is studied within the dynamical mean-field theory taking both electron-phonon and electron-electron interactions into account. We find that the observed insulating behavior at temperatures above the Jahn-Teller transition and the bond-length changes below it can most naturally by explained by assuming a strong electronic repulsion and a rather weak electron-phonon coupling.