Parameters dependent superconducting transition temperature in high temperature superconductors

TL;DR

This study uses an improved quantum Monte Carlo method to explore how doping and interaction parameters affect the superconducting transition temperature in a bilayer Hubbard model, shedding light on nickelate superconductors.

Contribution

It introduces a refined determinant quantum Monte Carlo approach to analyze parameter dependence of superconductivity in a bilayer Hubbard model, relevant to nickelate superconductors.

Findings

Interlayer spin-exchange $J$ is crucial for pairing.

On-site interaction $U$ has a doping-dependent effect.

Identifies key parameters influencing $T_c$ in nickelates.

Abstract

Understanding the evolution of the superconducting transition temperature in relation to doping and interaction strengths is one of the most challenging problems in high temperature superconductivity. By refining determinant quantum Monte Carlo algorithm, we characterize the parameter dependence of the superconducting transition temperature within a bilayer Hubbard model, which is sign-problem-free at arbitrary filling. A striking feature of this model is its similarities to the bilayer nickelate-based superconductor $\mathrm{La}_{3}\mathrm{Ni}_{2}\mathrm{O}_{7}$, where superconductivity emerge from the bilayer $\mathrm{Ni}\mathrm{O}_{2}$ planes. We find that interlayer spin-exchange $J$ is critical to interlayer pairing, ant that on-site interaction $U$ contributes negatively to superconductivity at low doping levels but positively to it at high doping levels. Our findings identify the key parameter dependent superconducting transition temperature in nickelate-based superconductors and provide a new understanding of the high temperature superconductivity.