Hole polaron propagation and pairing in a model for dopedCuO2

Abstract

We consider a two-dimensional one-band Hubbard Hamiltonian on a square lattice as a model for the doped ${\mathrm{CuO}}_2$ layers in the oxide superconductors. In a self-consistent mean-field approximation, doped away from the Néel state at the half-filled band, the elementary charged excitations take the form of spin polarons, i.e., self-localized states produced by a self-consistent polarization of the local staggered magnetization. Spin fluctuations around the equilibrium state mediate a dynamic attractive interaction between these polarons. The resulting pairing potential at the quasihole Fermi surface is found to be most strongly attractive for the d-wave singlet channel. The pairing potential is studied over a range of on-site repulsion U and band fillings, and comparisons are made with several previously reported results in this model.