Effects of the Hybridization on the Fermi Surface of an Extended $d-p$ Hubbard Model

TL;DR

This study examines how $d-p$ hybridization influences the Fermi surface topology in an extended Hubbard model, revealing significant effects in hole doping and consistency with experimental ARPES data.

Contribution

It provides a detailed analysis of the hybridization effects on Fermi surface crossover and superconductivity in a $d-p$ Hubbard model, incorporating doping asymmetries.

Findings

Hybridization significantly affects the hole-doped Fermi surface crossover.

The Fermi surface topology aligns with recent ARPES experimental results.

Hybridization impacts the superconducting order parameter near saddle points.

Abstract

The Fermi surface (FS) of an extended $d-p$ Hubbard model is investigated by a two-pole approximation in both situations with hole and electron doping. Using the factorization procedure proposed by Beenen and Edwards, superconductivity with singlet $d_{x^2-y^2}$-wave pairing is considered. The effects of the $d-p$ hybridization on the FS are the main focus in the present work. Nevertheless, the asymmetries between the hole- and electron-doped regimes and the effects of doping and Coulomb interaction on FS are also investigated. Particularly, it is shown that the crossover from hole-like to electron-like FS is deeply affected by the $d-p$ hybridization in the hole-doped case. It has been verified that the effect of the hybridization is very pronounced around the saddle points $(0,\pm\pi)$ and $(\pm\pi,0)$, where the intensity of the superconducting order parameter is maximum in the particular case of $d_{x^2-y^2}$-wave symmetry. In the electron-doped case, the crossover in the FS is not verified. The doping dependence of the FS topology in the hole- and electron-doped regimes is in agreement with recent experimental ARPES results for La$_{2-x}$Sr$_{x}$CuO$_4$ (hole doping) and Nd$_{2-x}$Ce$_x$CuO$_4$ (electron doping).