Superconductivity in the vicinity of charge ordered state in organic conductor beta-(meso-DMBEDT-TTF)_2PF_6

TL;DR

This paper theoretically investigates the competition between charge ordering and superconductivity in an organic conductor, revealing reentrant charge order and coexistence of triplet and singlet superconductivity driven by charge and spin fluctuations.

Contribution

It introduces a detailed analysis of the phase diagram of beta-(meso-DMBEDT-TTF)_2PF_6 using the extended Hubbard model, highlighting the emergence of reentrant charge order and multiple superconducting states.

Findings

Reentrant checkerboard charge order phase identified.

Triplet superconductivity driven by charge fluctuations.

Singlet superconductivity appears at low temperatures due to spin fluctuations.

Abstract

We study theoretically competition between the charge ordering and the superconductivity in two-dimensional organic conductor beta-(meso-DMBEDT-TTF)_2PF_6. We analyze the extended Hubbard model on a weakly-dimerized lattice based on the random phase approximation and Eliashberg equations. We found 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 the low temperature and high pressure region, the singlet superconductivity also appears due to the enhancement of the spin fluctuation.