Superconductivity and Mottness in Organic Charge Transfer Materials

TL;DR

This paper investigates the complex phase behavior of organic superconductors using advanced modeling, revealing unconventional superconductivity, pseudogap formation, and Fermi surface destruction consistent with experimental observations.

Contribution

It introduces a minimal Hubbard model analysis with quantum embedding methods that captures key phenomena like superconductivity and Mott transitions in organic materials.

Findings

Unconventional superconductivity confirmed in the model

Pseudogap formation during the Fermi liquid to Mott insulator crossover

Momentum-selective Fermi surface destruction predicted

Abstract

The phase diagrams of quasi two-dimensional organic superconductors display a plethora of fundamental phenomena associated with strong electron correlations, such as unconventional superconductivity, metal-insulator transitions, frustrated magnetism and spin liquid behavior. We analyze a minimal model for these compounds, the Hubbard model on an anisotropic triangular lattice, using cutting-edge quantum embedding methods respecting the lattice symmetry. We demonstrate the existence of unconventional superconductivity by directly entering the symmetry-broken phase. We show that the crossover from the Fermi liquid metal to the Mott insulator is associated with the formation of a pseudogap. The predicted momentum-selective destruction of the Fermi surface into hot and cold regions provides motivation for further spectroscopic studies. Our results are in remarkable agreement with experimental phase diagrams of $\kappa$-BEDT organics.