A possible demonstration of cooperative dynamical Jahn-Teller effect in Raman scattering spectrum of rhombohedral $LaMnO_3$

TL;DR

This paper suggests that a broad Raman scattering line in rhombohedral LaMnO3 can be explained by a cooperative dynamical Jahn-Teller effect, supported by lattice dynamics calculations including electron-phonon interactions.

Contribution

It introduces a novel explanation for Raman spectra features in LaMnO3 based on cooperative dynamical Jahn-Teller effects with an averaging scheme for one mode.

Findings

Broad Raman line at 640 cm^{-1} explained by Jahn-Teller effect

Lattice dynamics calculations support the hypothesis

Proposed averaging scheme for the effect

Abstract

The Raman scattering (RS) spectra of rhombohedral $LaMnO_3$ is considered. It is shown that broad high intensity RS line at 640 $cm^{-1}$ could be explained in the framework of cooperative dynamical Jahn-Teller effect. This hypothesis is illustrated through the lattice dynamics calculations explicitly allowing for the electron-phonon term both in crystal energy and in dynamical matrix. The averaging scheme for the one mode cooperative dynamical effect is proposed