Comparison of superconducting pairing in doped cuprates and nickelates within an extended Hubbard model

TL;DR

This study compares the superconducting pairing mechanisms in doped cuprates and nickelates using an extended Hubbard model and quantum Monte Carlo simulations, revealing dominant $d_{x^2-y^2}$ pairing and how doping and interaction strength influence it.

Contribution

It provides a comparative analysis of pairing symmetries and their dependencies in doped cuprates and nickelates within an extended Hubbard framework, highlighting key differences and similarities.

Findings

$d_{x^2-y^2}$ pairing is dominant at low temperatures in both materials.

Effective pairing interaction is slightly lower in nickelates than in cuprates.

Doping reduces the $d_{x^2-y^2}$ pairing interaction, while increasing Coulomb interaction enhances it.

Abstract

Within a Hubbard model, we investigate the superconducting pairing behavior of infinite-layer nickelate $\mathrm{NdNiO_2}$ and cuprate superconductors by using the determinant quantum Monte Carlo method. Our focus is on comparing their dominant pairing symmetries. The results indicate that the $d_{x^2-y^2}$ pairing interaction is significantly enhanced at low temperatures in both doped nickelates and cuprates, whereas other typical pairing symmetries are effectively suppressed, highlighting the dominance of the $d_{x^2-y^2}$ pairing form. Additionally, we find that the effective pairing interaction for $d_{x^2-y^2}$ pairing in doped nickelates is slightly lower than that in doped cuprates, which may be attributed to the different degrees of Fermi surface warping caused by the third-nearest hopping $t''$. Further studies show that the hole doping and interaction strength have significant effects on the $d_{x^2-y^2}$ pairing interaction within the selected parameter range. The $d_{x^2-y^2}$ pairing interaction is notably weakened when the hole doping increases, whereas it is significantly enhanced with increasing Coulomb interaction strength $U$. This comparative analysis reveals the similarities and differences in the pairing behaviors of doped nickelates and cuprates, which may provide further insights into understanding the superconducting properties of these two classes of materials.