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Metal-insulator Transition in a Pyrochlore-type Ruthenium oxide, Hg2Ru2O7

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

A new pyrochlore ruthenium oxide, Hg2Ru2O7 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_2g_3 electron configuration. Hg2Ru2O7 exhibits a first order metal-insulator transition at 107 K, accompanied by a structural transition from cubic to lower symmetry. The behavior of the magnetic susceptibility suggests the possible formation of a spin singlet in the insulating low temperature state.

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Ayako Yamamoto, Peter A. Sharma, Yoshihiko Okamoto, Aiko Nakao, Hiroko Aruga Katori, Seiji Niitaka, Daisuke Hashizume, Hidenori Takagi. 2007-02-17. Metal-insulator Transition in a Pyrochlore-type Ruthenium oxide, Hg2Ru2O7. https://doi.org/10.1143/jpsj.76.043703

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