d-wave superconductivity in a generalized Hubbard model

TL;DR

This paper investigates a generalized Hubbard model incorporating correlated and next-nearest neighbor hopping, revealing conditions for d-wave superconductivity and matching experimental critical temperatures in cuprates.

Contribution

It introduces an extended Hubbard model with t' and correlated hopping, demonstrating d-wave superconductivity emergence and aligning critical temperatures with experiments.

Findings

D-wave superconductivity appears at high t' and doping levels.

Antiferromagnetism is suppressed under certain conditions.

Calculated critical temperatures match experimental data.

Abstract

We consider an extended Hubbard model with nearest-neighbor correlated hopping and next nearest-neighbor hopping t' obtained as an effective model for cuprate superconductors. Using a generalized Hartree-Fock BCS approximation, we find that for high enough t' and doping, antiferromagnetism is destroyed and the system exhibits d-wave superconductivity. Near optimal doping we consider the effect of antiferromagnetic spin fluctuations on the normal self-energy using a phenomenological susceptibility. The resulting superconducting critical temperature as a function of doping is in good agreement with experiment.