Phase Diagram of Superconductivity on the Anisotropic Triangular Lattice Hubbard Model

TL;DR

This paper investigates the phase diagram of the anisotropic triangular lattice Hubbard model at half filling, revealing the prevalence of d-wave superconductivity near antiferromagnetic states, and aligns well with experimental observations.

Contribution

It provides a detailed phase diagram for the model using the FLEX method, highlighting the conditions for d-wave superconductivity in organic compounds.

Findings

d-wave superconductivity appears in a wide parameter region

phase diagram matches experimental results

superconductivity is adjacent to antiferromagnetic states

Abstract

We study the electronic states of the anisotropic triangular lattice Hubbard model at half filling, which is a simple effective model for the organic superconducting $\kappa$-BEDT-TTF compounds. We treat the effect of the Coulomb interaction by the fluctuation exchange (FLEX) method, and obtain the phase diagram of this model for various sets of parameters. It is shown that the d-wave superconductivity is realized in the wide region of the phase diagram, next to the antiferromagnetic states. The obtained phase diagram explains the characters of the experimental results very well.