Novel Charge Order and Superconductivity in Two-Dimensional Frustrated Lattice at Quarter Filling

TL;DR

This paper investigates the extended Hubbard model on a 2D anisotropic triangular lattice at quarter filling, revealing how Coulomb interactions induce charge order and triplet f-wave superconductivity, with implications for related organic materials.

Contribution

It demonstrates that Coulomb interactions promote charge fluctuations leading to charge-ordered metallic states and triplet f-wave superconductivity in a 2D frustrated lattice model.

Findings

Charge-ordered metallic state observed.

Triplet f-wave superconductivity induced.

Enhanced charge fluctuations due to Coulomb interaction.

Abstract

Motivated by the various physical properties observed in $\theta$-(BEDT-TTF)$_2$X, we study the ground state of extended Hubbard model on two-dimensional anisotropic triangular lattice at 1/4-filling with variational Monte Carlo method. It is shown that the nearest-neighbor Coulomb interaction enhances the charge fluctuation and it induces the anomalous state such as charge-ordered metallic state and the triplet next-nearest-neighbor $f$-wave superconductivity. We discuss the relation to the real materials and propose the unified view of the family of $\theta$-(BEDT-TTF)$_2$X.