Superconductivity in the Vicinity of Charge Ordered State in Organic Conductor β-(meso-DMBEDT-TTF)₂PF₆

Abstract

We study theoretically competition between the charge ordering and the superconductivity in the two-dimensional organic conductor β-(meso-DMBEDT-TTF)₂PF₆. We analyze the extended Hubbard model on a weakly-dimerized lattice based on the random phase approximation and Eliashberg equations. We found the reentrant behavior of the checkerbord-type charge-ordered phase in the phase diagram, and the triplet superconductivity due to the charge fluctuation in the neighboring region. In low temperatures, the singlet superconductivity also appears due to the enhancement of the spin fluctuation.