Magnetism and pressure-induced superconductivity of checkerboard-type charge-ordered molecular conductor β-(meso-DMBEDT-TTF)2X (X = PF6 and AsF6)

Takahisa Shikama, Tatsuya Shimokawa, Sanguchul Lee, Takayuki Isono, Akira Ueda, Kazuyuki Takahashi, Akiko Nakao, Reiji Kumai, Hironori Nakao, Kensuke Kobayashi, Youichi Murakami, Motoi Kimata, Hiroyuki Tajima, Kazuyuki Matsubayashi, Yoshiya Uwatoko, Yutaka Nishio, Koji Kajita, Hatsumi Mori

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


The metallic state of the molecular conductor β-(meso-DMBEDT-TTF)2X (DMBEDT-TTF = 2-(5,6-dihydro-1,3-dithiolo[4,5-b][1,4]dithiin-2-ylidene)-5,6-dihydro- 5,6-dimethyl-1,3-dithiolo[4,5-b][1,4]dithiin, X = PF6, AsF6) is transformed into the checkerboard-type charge-ordered state at around 75-80 K with accompanying metalinsulator (MI) transition on the anisotropic triangular lattice. With lowering temperatures, the magnetic susceptibility decreases gradually and reveals a sudden drop at the MI transition. By applying pressure, the charge-ordered state is suppressed and superconductivity appears in β-(meso-DMBEDT-TTF)2AsF6 as well as in the reported β-(meso-DMBEDT-TTF)2PF6. The charge-ordered spin-gapped state and the pressure-induced superconducting state are discussed through the paired-electron crystal (PEC) model, where the spin-bonded electron pairs stay and become mobile in the crystal, namely the valence-bond solid (VBS) and the resonant valence bonded (RVB) state in the quarter-filled band structure.

Original languageEnglish
Pages (from-to)1502-1513
Number of pages12
Issue number4
Publication statusPublished - 2012 Nov 29


  • Checkerboard-type charge ordering
  • Dimer state
  • Paired-electron crystal
  • Singlet state
  • Superconductor
  • Valence bond solid

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Inorganic Chemistry

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