Orbital structure of the effective pairing interaction in the high-temperature superconducting cuprates

TL;DR

This study investigates the orbital structure of the pairing interaction in high-temperature cuprate superconductors using a three-band Hubbard model, revealing dominant copper orbital interactions with notable oxygen orbital contributions, and supports the single-band approximation.

Contribution

It provides the first detailed analysis of the orbital structure of the pairing interaction in the three-band Hubbard model, validating the single-band model's applicability.

Findings

Interaction mainly acts between neighboring copper orbitals

Significant weight on surrounding oxygen orbitals

Supports the single-band model for cuprate superconductivity

Abstract

The nature of the effective interaction responsible for pairing in the high-temperature superconducting cuprates remains unsettled. This question has been studied extensively using the simplified single-band Hubbard model, which does not explicitly consider the orbital degrees of freedom of the relevant CuO$_2$ planes. Here, we use a dynamic cluster quantum Monte Carlo approximation to study the orbital structure of the pairing interaction in the three-band Hubbard model, which treats the orbital degrees of freedom explicitly. We find that the interaction predominately acts between neighboring copper orbitals, but with significant additional weight appearing on the surrounding bonding molecular oxygen orbitals. By explicitly comparing these results to those from the simpler single-band Hubbard model, our study provides strong support for the single-band framework for describing superconductivity in the cuprates.