Raman signatures of charge ordering in K0.3WO3

D. M. Sagar*, D. Fausti, S. van Smaalen, P. H. M. van Loosdrecht

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

We present polarization- and temperature-dependent Raman spectroscopic study of hexagonal tungsten bronze, K0.3WO3. The observed asymmetry in phonon line shapes indicate the presence of strong lattice anharmonicity arising due to the nonstoichiometry of the material. We observed a broad multipeak Raman feature at low frequency due to the local modes of K atoms known as local structural excitations. The observed vibrational features indicate a second-order phase transition around T=200 K accompanied by a frequency softening of low-frequency phonon modes. The observed phonon anomalies hint a physical picture involving a continuous symmetry change toward a charge-ordered state below 200 K. These observations indicate that K0.3WO3 may exhibit a weak charge-density-wave ground state at low temperatures.

Original languageEnglish
Article number045124
Pages (from-to)045124-1-045124-7
Number of pages7
JournalPhysical Review. B: Condensed Matter and Materials Physics
Volume81
Issue number4
DOIs
Publication statusPublished - Jan-2010

Keywords

  • HEXAGONAL TUNGSTEN BRONZES
  • SUPERCONDUCTING PROPERTIES
  • EXCITATION SPECTRUM
  • DENSITY WAVES
  • TRANSITION
  • PHONONS
  • SYSTEM
  • KXWO3

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