Metal-insulator transition in a pyrochlore-type ruthenium oxide, Hg 2Ru2O7

Ayako Yamamoto, Peter A. Sharma, Yoshihiko Okamoto, Aiko Nakao, Hiroko Aruga Katori, Seiji Niitaka, Daisuke Hashizume, Hidenori Takagi

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A new pyrochlore ruthenium oxide, Hg2Ru2O 7, was synthesized under a high pressure of 6 GPa. In contrast to the extensively studied Ru4+ oxides, this compound possesses a novel Ru5+ valence state, corresponding to a half-filled t 2g3 electron configuration. Hg2Ru 2O7 exhibits a first order metal-insulator transition at 107 K, accompanied by a structural transition from a cubic to lower symmetry. The behavior of the magnetic susceptibility suggests the possible formation of a spin singlet in the insulating low temperature state.

Original languageEnglish
Article number043703
JournalJournal of the Physical Society of Japan
Issue number4
Publication statusPublished - 2007 Apr 1



  • Geometrical frustration
  • Metal-insulator transition
  • Pyrochlore-type structure
  • Ruthenium oxide

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Yamamoto, A., Sharma, P. A., Okamoto, Y., Nakao, A., Aruga Katori, H., Niitaka, S., Hashizume, D., & Takagi, H. (2007). Metal-insulator transition in a pyrochlore-type ruthenium oxide, Hg 2Ru2O7. Journal of the Physical Society of Japan, 76(4), [043703].