Doping asymmetry in the three-band Hamiltonian for cuprate ladders: failure of the standard model of superconductivity in cuprates

The relevance of the single-band two-dimensional Hubbard model to superconductivity in the doped cuprates has recently been questioned, based on Density matrix Renormalization Group (DMRG) computations on extended t-J models that found superconductivity over unrealistically broad doping region upon electron-doping, yet complete absence of superconductivity for hole-doping. We report very similar results from DMRG calculations on Cu${}_2$O${}_3$ two-leg ladder within the parent three-band correlated-electron Hamiltonian. The strong asymmetry found in our calculations are in contradiction to the deep and profound symmetry between electron- and hole-doped cuprate superconductors, apart from their critical temperatures, that has been found from recent experiments.