Charge ordered metal and pressure-induced superconductivity in the two-dimensional organic conductor β′′-(DODHT) 2PF6

Akito Kobayashi, Yoshikazu Suzumura, Momoka Higa, Ryusuke Kondo, Seiichi Kagoshima, Hiroyuki Nishikawa

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

The superconductivity in a quasi-two-dimensional organic conductor, β′′-(DODHT)2PF6 salt, which is expected to appear after the melting of a charge ordering (CO) state, has been examined using an extended Hubbard model with anisotropy for both the transfer energies and the nearest-neighbor repulsive interactions between the DODHT molecules. The fluctuation is treated by the random phase approximation based on mean-field calculation of the CO. When pressure is applied, an insulating state with CO (COI) changes into a metallic state with weakened CO (COM) at an intermediate pressure, and a normal state without CO emerges at higher pressures. For the COM state at intermediate pressure, the COI state and the normal state also exist as metastable states, and their free energies are nearly the same within a narrow energy range of 10-3eV. Thus these three states may coexist with each other by forming a phase separation at finite temperature. We find that the spin fluctuation around such a mean-field COM state gives rise to a superconducting state with a full gap. Further, we suggest that d-wave superconductivity mediated by the charge fluctuation occurs in the normal state with a quasi-one-dimensional Fermi surface when the nearest-neighbor interaction becomes as large as the on-site interaction.

Original languageEnglish
Article number125205
JournalJournal of Physics Condensed Matter
Volume20
Issue number12
DOIs
Publication statusPublished - Mar 26 2008
Externally publishedYes

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Organic conductors
Superconductivity
superconductivity
conductors
Metals
metals
interactions
Spin fluctuations
metastable state
Hubbard model
Fermi surfaces
Fermi surface
energy transfer
free energy
melting
Phase separation
Energy transfer
Free energy
salts
anisotropy

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials

Cite this

Charge ordered metal and pressure-induced superconductivity in the two-dimensional organic conductor β′′-(DODHT) 2PF6. / Kobayashi, Akito; Suzumura, Yoshikazu; Higa, Momoka; Kondo, Ryusuke; Kagoshima, Seiichi; Nishikawa, Hiroyuki.

In: Journal of Physics Condensed Matter, Vol. 20, No. 12, 125205, 26.03.2008.

Research output: Contribution to journalArticle

Kobayashi, Akito ; Suzumura, Yoshikazu ; Higa, Momoka ; Kondo, Ryusuke ; Kagoshima, Seiichi ; Nishikawa, Hiroyuki. / Charge ordered metal and pressure-induced superconductivity in the two-dimensional organic conductor β′′-(DODHT) 2PF6. In: Journal of Physics Condensed Matter. 2008 ; Vol. 20, No. 12.
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