Suppression of superconductivity in the three-band Hubbard model for cuprate ladders*

We present Density Matrix Renormalization Group calculations of the spin gap and pairing correlations in the Hubbard ladder model on a copper oxide lattice with multiband topology. The large spin gaps for the undoped ladder are in close agreement with the previous DMRG studies of the single-band ladder model. Dopants equally reside both on the rung and leg oxygen sites, and the extrapolated spin gap considerably decreases with increasing doping concentration. The extrapolated pair-pair correlations decrease more sharply than their single-band counterparts. Our quantitative results on the realistic sets of parameters for the cuprates show that the power-law decay of the correlation function is nearly indistinguishable from that of free fermions. Our DMRG studies suggest that the weakly-doped single-band Hubbard model is not adequate for both ladder and layered superconducting materials. These results also raise disturbing questions about the applicability of many of the existing theories of superconductivity in cuprates, which assume gapped spin liquid states proximate to superconductivity.

Reference: arXiv:2010.10609