Orbital wave in the Raman scattering cross section of LaMnO3

TL;DR

This paper investigates the polarization-dependent Raman scattering in LaMnO3 below its magnetic transition, revealing two peaks linked to Jahn-Teller phonons and orbital waves, highlighting electron-phonon interactions.

Contribution

It provides the first detailed calculation of polarization-dependent Raman spectra in LaMnO3, identifying specific phonon and orbital wave couplings.

Findings

Two strong Raman peaks around MnO6 stretching phonon frequency.

One peak with Ag symmetry is a Jahn-Teller phonon coupled to an orbital wave.

Another peak with Bg symmetry is an orbital wave coupled to a Q2 phonon mode.

Abstract

We calculated the polarization-dependent Raman scattering cross section spectra of LaMnO3 below the A-type magnetic ordering temperature. Two strong peaks appear around the MnO6 octahedra stretching phonon frequency. One mode shows Ag symmetry, while the other mode shows Bg symmetry. We found that the Ag symmetry peak is a Jahn-Teller phonon coupled to the orbital wave and the Bg symmetry peak is an orbital wave coupled to a Q2 phonon mode via the Jahn-Teller electron phonon coupling.