A Raman study of the charge-density-wave state in A(0.3)MoO(3) (A = K, Rb)

D. M. Sagar, D. Fausti, S. Yue, C. A. Kuntscher, S. van Smaalen, P. H. M. van Loosdrecht*

*Corresponding author for this work

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Abstract

We report a comparative Raman spectroscopic study of the quasi-one-dimensional charge-density-wave (CDW) systems A(0.3)MoO(3) (A = K, Rb). Temperature- and polarization-dependent experiments reveal charge-coupled vibrational Raman features. The strongly temperature-dependent collective amplitudon modes in the two materials differ by about 3 cm(-1), thus revealing the role of the alkali atom. We discuss the observed vibrational features in terms of the CDW ground state accompanied by a change in the crystal symmetry. A frequency-kink in some modes seen in K(0.3)MoO(3) between T = 80 and 100K supports the first-order lock-in transition, unlike the case of Rb(0.3)MoO(3). The unusually sharp Raman lines (limited by the instrumental response) at very low temperatures and their temperature evolution suggests that the decay of the low-energy phonons is strongly influenced by the presence of the temperature-dependent CDW gap.

Original languageEnglish
Article number023043
Number of pages11
JournalNew Journal of Physics
Volume10
Issue number2
DOIs
Publication statusPublished - 26-Feb-2008

Keywords

  • LOW-TEMPERATURES
  • SINGLE-CRYSTALS
  • K0.3MOO3
  • SPECTROSCOPY
  • EXCITATIONS
  • SCATTERING
  • K0.30MOO3
  • RB0.3MOO3
  • SPECTRA
  • BRONZE

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