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.
@article{arxiv.0807.2541,
title = {Observation of charge-density-wave excitations in manganites},
author = {A. Nucara and P. Maselli and P. Calvani and R. Sopracase and M. Ortolani and U. Schade and G. Gruener and M. Cestelli Guidi and J. Garcia},
journal= {arXiv preprint arXiv:0807.2541},
year = {2009}
}