Quantum Monte Carlo evidence for superconductivity in the three-band Hubbard model in two dimensions

TL;DR

This study uses quantum Monte Carlo simulations to provide evidence that the three-band Hubbard model exhibits superconducting correlations, supporting the electronic origin of high-temperature superconductivity in cuprates.

Contribution

It demonstrates that the three-band Hubbard model shows increasing pairing correlations with system size, indicating potential superconductivity in both charge-transfer and Mott-Hubbard regimes.

Findings

Pairing correlations grow with system size

Superconducting correlations increase with Coulomb repulsion and level off-set

Evidence supports electronic origin of high-Tc superconductivity

Abstract

A possibility of the electronic origin of the high-temperature superconductivity in cuprates is probed with the quantum Monte Carlo method by revisiting the three-band Hubbard model comprising Cu$3d_{x^2-y^2}$ and O$2p_\sigma$ orbitals. The $d_{x^2-y^2}$ pairing correlation is found to turn into an increasing function of the repulsion $U_d$ within the $d$ orbitals or the $d$-$p$ level off-set $\Delta \varepsilon$, where the correlation grows with the system size. % and is long-ranged as also seen from a real-space analysis. We have detected this in both the charge-transfer and Mott-Hubbard regimes upon entering the strong-correlation region ($U_d$ or $\Delta \varepsilon >$ bare band width).