Antiferromagnetic fluctuations and a dominant $d_{xy}$-wave pairing symmetry in nickelate-based superconductors

TL;DR

This study uses quantum Monte Carlo simulations on a two-band Hubbard model to show that nickelate-based superconductors predominantly exhibit $d_{xy}$-wave pairing driven by strong electron correlations, without long-range antiferromagnetic order.

Contribution

It provides the first detailed numerical evidence that $d_{xy}$-wave pairing dominates in nickelates and clarifies the role of electron correlations and magnetic fluctuations in their superconductivity.

Findings

$d_{xy}$-wave pairing dominates at low temperature

Superconductivity driven by strong electron-electron correlations

No evidence of long-range antiferromagnetic order

Abstract

Motivated by recent experimental studies on superconductivity found in nickelate-based materials, we study the temperature dependence of the spin correlation and the superconducting pairing interaction within an effective two-band Hubbard model by the quantum Monte Carlo method. Based on parameters extracted from first-principles calculations, our intensive numerical results reveal that the pairing with a $d_{xy}$-wave symmetry firmly dominates over other pairings at low temperature, which is mainly determined by the Ni 3$d$ orbital. It is also found that the effective pairing interaction is enhanced as the on-site interaction increases, demonstrating that the superconductivity is driven by strong electron-electron correlation. Even though the $(\pi,\pi)$ antiferromagnetic correlation could be enhanced by electronic interaction, there is no evidence for long-range antiferromagnetic order exhibited in nickelate-based superconductors. Moreover, our results offer possible evidence that the pure electron correlation may not account for the charge density wave state observed in nickelates.