Observation of charge-density-wave excitations in manganites

TL;DR

This study observes charge-density-wave excitations in manganites through optical conductivity measurements, revealing peaks linked to pinned phasons and supporting a CDW-based understanding of charge order in these materials.

Contribution

It provides experimental evidence of CDW excitations in manganites and quantifies electron-phonon coupling, effective mass, and dielectric contributions, advancing the understanding of charge order mechanisms.

Findings

Peaks in optical conductivity indicate CDW excitations.

Quantitative analysis of electron-phonon coupling and effective mass.

Supports CDW theory as a model for charge order in manganites.

Abstract

In the optical conductivity of four different manganites with commensurate charge order (CO), strong peaks appear in the meV range below the ordering temperature T_{CO}. They are similar to those reported for one-dimensional charge density waves (CDW) and are assigned to pinned phasons. The peaks and their overtones allow one to obtain, for La{1-n/8}Ca{n/8}$MnO{3} with n = 5, 6, the electron-phonon coupling, the effective mass of the CO system, and its contribution to the dielectric constant. These results support a description of the CO in La-Ca manganites in terms of moderately weak-coupling and of the CDW theory.