Mean field analysis of a model for superconductivity in an antiferromagnetic background

TL;DR

This paper analyzes a lattice fermion model with antiferromagnetic background to understand superconductivity, showing that antiferromagnetic order enhances the critical temperature and favors a d-wave gap symmetry.

Contribution

It introduces a mean field analysis of a fermion lattice model incorporating antiferromagnetic order, linking it to high-temperature superconductivity and heavy fermion systems.

Findings

Superconducting critical temperature is strongly enhanced by antiferromagnetic order.

The most stable superconducting channel exhibits a d_{x^2-y^2}-wave gap.

The model provides insights into coexistence of antiferromagnetism and superconductivity.

Abstract

We study a lattice fermion model for superconductivity in the presence of an antiferromagnetic background, described as a fixed external staggered magnetic field. We discuss the possibility that our model provides an effective description of coexistence of antiferromagnetic correlations and superconductivity, and its possible application to high temperature superconductivity. We also argue that, under certain conditions, this model describes a variant of the periodic Anderson model for heavy fermions. Using a path integral formulation we construct mean field equations, which we study in some detail. We evaluate the superconducting critical temperature and show that it is strongly enhanced by antiferromagnetic order. We also evaluate the superconducting gap, the superconducting density of states, and the tunneling conductivity, and show that the most stable channel usually has a $d_{x^2-y^2}$-wave gap.