Disordered polyhalide anion effect on the Fermi surface of the incommensurate organic superconductor (MDT-TSF)I0.77Br0.52

Tadashi Kawamoto, Takehiko Mori, Kengo Enomoto, Takako Konoike, Taichi Terashima, Shinya Uji, Hiroshi Kitagawa, Kazuo Takimiya, Tetsuo Otsubo

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Abstract

The effect of disorder in polyhalide anions is investigated in terms of the degree of charge transfer and the Fermi surface in the incommensurate organic superconductor (MDT-TSF)I0.77Br0.52, where MDT-TSF is methylenedithio-tetraselenafulvalene. The Raman spectra suggest that the infinite polyhalide chains include the asymmetric trihalide anion I 2Br- and that the degree of charge transfer from the donor molecule to the anion is 0.429, estimated from the lattice constants. The Shubnikov-de Haas (SdH) oscillation is in good agreement with this charge transfer degree. The beating behavior of the SdH oscillation gives a large interlayer transfer integral, which is consistent with a corrugated conducting sheet structure. The randomness of the disordered anions reduces the periodicity of the incommensurate anion potential; this destroys the Fermi surface reconstruction by the incommensurate anion potential. The factor dominating the superconducting transition temperature is not the randomness of the polyhalide anions but the effective cyclotron mass enhancement, i.e., the many-body effect.

Original languageEnglish
Article number094518
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume84
Issue number9
DOIs
Publication statusPublished - 2011 Sep 19
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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