Coexistence of d_{x^2-y^2}-Wave Superconductivity and Antiferromagnetism Induced by a Staggered Field

TL;DR

This study uses exact diagonalization to show that a staggered magnetic field in the 2D t-J model enhances d_{x^2-y^2}-wave superconductivity and promotes coexistence with antiferromagnetism at low hole densities.

Contribution

It demonstrates that a staggered field can simultaneously strengthen d-wave pairing and antiferromagnetic order in the t-J model, revealing a mechanism for their coexistence.

Findings

Staggered field increases attraction between holes.

d_{x^2-y^2}-wave correlations are enhanced by the field.

Coexistence of superconductivity and antiferromagnetism is observed.

Abstract

The two-dimensional t-J model in a staggered field is studied by exact diagonalization of small clusters. For the low-hole-density region and a realistic value of J/t, it is found that the presence of a staggered field strengthens the attraction between two holes. With increasing field, the d_{x^2-y^2}-wave superconducting correlations are enhanced while the extended-s-wave ones hardly change. This implies that coexistence of the d_{x^2-y^2}-wave superconducting order and the commensurate antiferromagnetic order occurs in a staggered field.