Raman scattering study of hexaboride crystals

N. Ogita, S. Nagai, N. Okamoto, F. Iga, S. Kunii, J. Akimitsu, M. Udagawa

Research output: Contribution to journalConference articlepeer-review

18 Citations (Scopus)


The valence-dependent Raman scattering spectra has been found for the RB6 crystals (R = Ca2+, Yb2+, Ce3+, Pr3+, Gd3+, and Dy3+). In the divalent crystals of CaB6 and YbB6, Eg phonon shows doublet, while the line shape is a broad single peak for the trivalent case. Since both doublet peaks satisfy the selection rule due to the cubic symmetry, the doublet spectra is not explained by the structural phase transition, but by the anisotropic charge distribution on B6. In the trivalent crystals, the two kind of the extra peaks have been commonly observed at around 200 cm-1 and at around 1400 cm-1. The peak intensities of the former decrease with decreasing temperature, and their peak energies increase with increasing lattice constant. These anomalous features are well explained by the vibration of R ion in the oversized cage space formed octahedral B6 molecule. Thus, this new excitation can be attributed to a local vibration of the R ion, which can be regarded as "rattler."

Original languageEnglish
Pages (from-to)131-134
Number of pages4
JournalPhysica B: Condensed Matter
Issue number1-2
Publication statusPublished - Apr 2003
Externally publishedYes
EventT2PAM - Higashi-Hiroshima, Japan
Duration: Aug 16 2002Aug 19 2002


  • Hexaborides
  • Local vibration mode
  • Raman scattering

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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