Revision of model parameters for kappa-type charge transfer salts: an ab initio study

TL;DR

This study uses ab initio density functional theory calculations to update the model parameters for kappa-(BEDT-TTF)2X charge transfer salts, refining the understanding of their complex phase diagram.

Contribution

The paper provides revised hopping parameters for the Hubbard model of kappa-(BEDT-TTF)2X salts based on ab initio calculations, improving the accuracy of theoretical descriptions.

Findings

Revised parameters suggest less frustration and more anisotropic lattices.

Updated parameters better align theoretical models with experimental observations.

Implications for the phase diagram and physical properties are discussed.

Abstract

Intense experimental and theoretical studies have demonstrated that the anisotropic triangular lattice as realized in the kappa-(BEDT-TTF)2X family of organic charge transfer (CT) salts yields a complex phase diagram with magnetic, superconducting, Mott insulating and even spin liquid phases. With extensive density functional theory (DFT) calculations we refresh the link between manybody theory and experiment by determining hopping parameters of the underlying Hubbard model. This leads us to revise the widely used semiempirical parameters in the direction of less frustrated, more anisotropic triangular lattices. The implications of these results on the systems' description are discussed.