Gossamer Superconductivity near Antiferromagnetic Mott Insulator in Layered Organic Conductors

TL;DR

This paper investigates the transition from Gossamer superconductivity to antiferromagnetic Mott insulator in layered organic conductors using a Hubbard model with a spin exchange, revealing a first order phase transition.

Contribution

It introduces a Gutzwiller variational approach to model the phase transition in layered organic superconductors, highlighting the coexistence and transition between superconducting and insulating states.

Findings

Gossamer superconductor at low U

Antiferromagnetic Mott insulator at high U

First order phase transition between phases

Abstract

Layered organic superconductors are on the verge of the Mott insulator. We use Gutzwiller variational method to study a Hubbard model including a spin exchange coupling term. The ground state is found to be a Gossamer superconductor at small on-site Coulomb repulsion U and an antiferromagnetic Mott insulator at large U, separated by a first order phase transition. Our theory is qualitatively consistent with major experiments reported in organic superconductors.