Interplay of D-wave Superconductivity and Antiferromagnetism in the Cuprate Superconductors: Phase Separation and the Pseudogap Phase Diagram

TL;DR

This paper investigates how d-wave superconductivity and antiferromagnetism interact in cuprates using a Hubbard model, revealing phase separation and insights into the pseudogap phase diagram, including the effects of inhomogeneity.

Contribution

It introduces a model showing phase separation driven by intersite attraction, linking it to features of the pseudogap phase and inhomogeneity in cuprates.

Findings

Phase separation occurs in the model, influencing the pseudogap phase.

The phase separation boundary aligns with the upper crossover in the phase diagram.

Inhomogeneity results from incomplete phase separation, affecting transition temperatures.

Abstract

To understand the interplay of d-wave superconductivity and antiferromagnetism in the cuprates, we consider a two-dimensional extended Hubbard model with nearest neighbor attractive interaction. Free energy of the homogeneous (coexisting superconducting and antiferromagnetic) state calculated a s a function of the band filling shows a region of of phase separation. The phase separation caused by the intersite attractive force leads to novel insights into salient features of the pseudogap phase diagram. In particular, the upper crossover curve can be identified with the phase separation boundary. At zero temperature, the boundary constitutes a critical point. The inhomogeneity observed in the underdoped cuprates is a consequence of incomplete phase separation. The disorder (inhomogeneity) brings about the disparity between the high pseudogap temperature and the low bulk superconducting transition temperature.