We report inelastic light scattering experiments in the spin-chain and ladder system Sr_14-xCa_xCu_24O_41. A depletion of an electronic background is observed for 0 < x < 5 at low temperatures and with light polarization both parallel to the leg and rung directions. This points to the formation of 2D charge density wave in the ladders. Furthermore, the Ca-substitution dependence of the 305- and 249-cm-1 modes, sensitive to the lattice modulations of the respective chain and ladder system, suggests that the charge dynamics in the ladders is strongly influenced by the structural incommensurability.
@article{arxiv.cond-mat/0601203,
title = {Charge density waves in Sr_14-xCa_xCu_24O_41: electron correlations vs. structural effects},
author = {K. -Y. Choi and M. Grove and P. Lemmens and M. Fischer and G. Güntherodt and U. Ammerahl and B. Büchner and G. Dhalenne and A. Revcolevschi and J. Akimitsu},
journal= {arXiv preprint arXiv:cond-mat/0601203},
year = {2009}
}
Comments
5 pages, 4 figures, to be published in Phys. Rev. B