Combined density-functional and dynamical cluster quantum Monte Carlo calculations for three-band Hubbard models for hole-doped cuprate superconductors

TL;DR

This study combines density functional theory and quantum Monte Carlo methods to analyze how parameters affect the superconducting transition temperature in hole-doped cuprate models, revealing sensitivity to model parameters.

Contribution

It introduces a combined LDA-DFT and QMC approach to study parameter dependence of Tc in three-band Hubbard models for cuprates, highlighting the impact of basis set choice.

Findings

Tc depends sensitively on model parameters.

N=1 basis set reproduces d-wave superconductivity.

N=0 basis set does not produce d-wave transition.

Abstract

Using a combined local density functional theory (LDA-DFT) and quantum Monte Carlo (QMC) dynamic cluster approximation approach, the parameter dependence of the superconducting transition temperature Tc of several single-layer hole-doped cuprate superconductors with experimentally very different Tcmax is investigated. The parameters of two different three-band Hubbard models are obtained using the LDA and the downfolding Nth-order muffin-tin orbital technique with N=0 and 1 respectively. QMC calculations on 4-site clusters show that the d-wave transition temperature Tc depends sensitively on the parameters. While the N=1 MTO basis set which reproduces all three $pd\sigma$ bands leads to a d-wave transition, the N=0 set which merely reproduces the LDA Fermi surface and velocities does not.