Charge ordering signatures in the optical properties of beta-Na0.33V2O5

Presura, C.; Popinciuc, M.; van Loosdrecht, P. H. M.; van der Marel, D.; Mostovoy, M.; Yamauchi, T.; Ueda, Y.

Charge ordering signatures in the optical properties of beta-Na0.33V2O5

Authors

Presura, C.

Popinciuc, M.

van Loosdrecht, P. H. M.

Description

Temperature dependent optical spectra are reported for beta-Na0.33V2O5. The sodium ordering transition at T_Na = 240 K, and in particular the charge ordering transition at T_MI = 136 K strongly influence the optical spectra. The metal-insulator transition at \tmi leads to the opening of a psuedogap (\hbarω= 1700 cm-1), and to the appearance of a large number of optical phonons. These observations, and the presence of a mid-infrared band (typical for low dimensional metals) strongly suggests that the charge carriers in beta-Na0.33V2O5 are small polarons.
To be published in PRL