Pressure-induced metal-semiconductor-metal transitions in an MMX-chain complex, Pt2(C2H5CS2)4I

Atsushi Kobayashi, Aya Tokunaga, Ryuichi Ikeda, Hajime Sagayama, Yusuke Wakabayashi, Hiroshi Sawa, Masato Hedo, Yoshiya Uwatoko, Hiroshi Kitagawa

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7 Citations (Scopus)


The electrical conductivity and X-ray diffraction measurements were performed for a highlyconductive halogen-bridged binuclear-metal mixed-valence complex (the so-called MMX chain), Pt2(C2H 5CS2)4I, under high pressure up to 2.5 GPa. The complex exhibited pressure-induced metal-semiconductor-metal transitions at 0.5 and 2.1 GPa. The X-ray diffuse scatterings were observed at k = n+0.5 (n: integer) under ambient pressure, which are derived from the charge-density wave (CDW: ⋯Pt2+-Pt2+⋯I-Pt3+-Pt 3+-I⋯) fluctuation in the MMX chain. Above 0.5 GPa, where the pressure-induced metal-semiconductor transition occurred, these scatterings disappeared. The electronic phases under high pressure (P) were found to be attributable to the metallic averaged-valence state (AV: -Pt2.5+- Pt2.5+-I-Pt2.5+-Pt2.5+-I-) with CDW fluctuation of P < 0.5 GPa, semiconducting charge-polarization state (CP: ⋯Pt2+-Pt3+-I⋯Pt2+-Pt 3+-I⋯) of 0.5 < P < 2.1 GPa, and metallic AV state of P > 2.1 GPa. The electronic state of Pt2(C2H 5CS2)4I is very sensitive to pressure, which implies that the phase competition among the CP, CDW, and AV phases is present in the MMX chain.

Original languageEnglish
Pages (from-to)3567-3570
Number of pages4
JournalEuropean Journal of Inorganic Chemistry
Issue number18
Publication statusPublished - 2006 Sept 18


  • Conducting materials
  • High pressure
  • MMX chain
  • Metal-insulator transition
  • Mixed-valent compounds


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