s-s*-d-wave superconductor on a square lattice and its BCs phase diagram

TL;DR

This paper investigates an extended Hubbard model on a square lattice to understand the phase diagram and superconducting properties relevant to doped cuprates, considering effects of temperature and orthorhombicity.

Contribution

It provides a detailed phase diagram for an extended Hubbard model, including effects of temperature and orthorhombicity, and maps it onto a simplified Hamiltonian.

Findings

Identified the parameter region relevant for cuprates.

Analyzed the impact of temperature on gap symmetry.

Mapped the complex model onto a simpler linearized Hamiltonian.

Abstract

We study an extended Hubbard model with on-site repulsion and nearest neighbors attraction which tries to mimic some of the experimental features of doped cuprates in the superconducting state. We draw and discuss the phase diagram as a function of the effective interactions among electrons for a wide range of doping concentrations. We locate the region which is relevant for the cuprates setting some constraints on the parameters which may be used in this kind of effective models. We also study the effects of temperature and orthorrombicity on the symmetry and magnitude of the gap function, and map the model onto a simpler linearized hamiltonian, which produces similar phase diagrams.