Mean field solutions to singlet hopping and superconducting pairing within a two-band Hubbard model

TL;DR

This paper derives mean field solutions for a two-band Hubbard model describing singlet hopping and superconducting pairing in high-temperature cuprate superconductors, using polynomial Green functions and Wannier coefficients.

Contribution

It provides a rigorous derivation of higher order correlation functions for singlet hopping and pairing within a two-band Hubbard model.

Findings

Explicit expressions for correlation functions are obtained.

The approach uses invariant classes of polynomial Green functions.

Results contribute to understanding high-$T_c$ superconductivity mechanisms.

Abstract

The mean field Green function solution of the two-band singlet-hole Hubbard model for high-$T\sb{c}$ superconductivity in cuprates (Plakida, N.M. et al., Phys. Rev. B51, 16599 (1995), JETP 97, 331 (2003)) involves expressions of higher order correlation functions describing respectively the singlet hopping and the superconducting pairing. Rigorous derivation of their values is reported based on the finding that specific invariant classes of polynomial Green functions in terms of the Wannier overlap coefficients $\nu\sb{ij}$ exist.