Antiferromagnetism and Superconductivity in a model of Quasi 1D Organic Conductors

TL;DR

This paper uses a two-step renormalization group approach to analyze the competition between antiferromagnetism and superconductivity in a 2D Hubbard model, revealing phase behaviors relevant to quasi 1D organic conductors.

Contribution

It demonstrates that a simple anisotropic 2D Hubbard model can effectively capture the ground-state phase diagram of quasi 1D organic conductors, highlighting the dominance of AFM and SDW phases.

Findings

Ground-state phase diagram is mostly AFM, matching experiments.

AFM is localized in the strong-coupling limit with electrons confined in chains.

A small weak-coupling region shows transverse two-particle hopping dominating over magnetism.

Abstract

I apply a two-step renormalization group method to the study of the competition between antiferromagnetism (AFM) and superconductivity in an anisotropic 2D Hubbard model. I show that this simple model captures the essentials of the ground-state phases of the quasi 1D organic conductors. As found experimentally, the ground-state phase diagram is mostly AFM. The AFM is localized in the strong-coupling limit where the electrons are confined in the chains. It is an SDW in the weak-coupling limit where interchain hopping is present. There is a tiny region in the weak-coupling regime where transverse two-particle hopping is dominant over magnetism.