Manifestation of vibronic dynamics in infrared spectra of Mott insulating fullerides

TL;DR

This paper develops a first-principles theoretical framework to analyze vibronic dynamics in infrared spectra of Mott-insulating fullerides, revealing how Jahn-Teller effects influence spectral features and their temperature evolution.

Contribution

It introduces the first-principles theory for infrared spectra of dynamical Jahn-Teller systems, applied specifically to Cs$_3$C$_{60}$, elucidating vibronic effects in correlated materials.

Findings

Dynamical Jahn-Teller effect manifests in infrared spectra.

Temperature-dependent spectral line shape explained.

Transition to Fano resonance in metallic fullerides discussed.

Abstract

The fine structure and temperature evolution of infrared spectra have been intensively used to probe the nature of Jahn-Teller dynamics in correlated materials. At the same time, theoretical framework to adequately extract the information on the complicated vibronic dynamics from infrared spectra is still lacking. In this work, the first-principles theory of the infrared spectra of dynamical Jahn-Teller system is developed and applied to the Mott-insulating Cs$_3$C$_{60}$. With the calculated coupling parameters for Jahn-Teller and infrared active vibrational modes, the manifestation of the dynamical Jahn-Teller effect in infrared spectra is elucidated. In particular, the temperature evolution of the infrared line shape is explained. The transformation of the latter into Fano resonance type in metallic fulleride is discussed on the basis of obtained results.