Slave-Boson Three-Band Model with O-O Hopping for High-Tc Superconductors

TL;DR

This paper develops an analytical slave boson mean-field model for weakly doped CuO2 planes, revealing how O-O hopping influences the stability of conducting and insulating states, and matches ARPES spectra of high-Tc superconductors.

Contribution

It introduces a novel analytical approach incorporating O-O hopping in the three-band model, explaining doping effects and spectral features in high-Tc cuprates.

Findings

Finite O-O hopping expands the stability of the conducting state.

Charge transfer energy saturates at 4|t'| for large _{pd}.

Model matches ARPES spectra of Bi2212 and LSCO.

Abstract

Slave boson mean-field approximation is carried out analytically for weakly doped CuO_2 conduction planes, characterized by Cu-O charge transfer energy \Delta_{pd}, Cu-O hopping t_0, O-O hopping t' and repulsion U_d between holes on Cu site taken as infinite. At zero doping \delta, finite negative t',|t'|<t_0/2, expands the range of stability of the covalent, conducting state on the expense of the insulating state which, however, remains stable at larger \Delta_{pd}. For sufficiently large \Delta_{pd} the renormalized charge transfer energy saturates at 4|t'| instead of decreasing to zero, as at t'=0 case. In contrast to t', finite \delta suppresses the insulating state nearly symmetrically with respect to the sign of \delta. The regime with charge transfer energy renormalized close to 4|t'| fits remarkably well the ARPES spectra of Bi2212 and LSCO, and, in the latter case, explains the observed strong doping dependence of the Cu-O hopping.