Relation between the one-band and three-band Hubbard models of cuprates via spectroscopy and scattering experiments

The one-band and three-band Hubbard models which describe the electronic structure of cuprate superconductors are known to provide very different values of effective electronic parameters, such as the on-site Coulomb energy and the hybridization strength. In contrast, electronic parameters of several cuprates obtained from the three-band model are quite similar to corresponding values from cluster model calculations used to simulate experimental spectroscopy and scattering results. In this work, the Heisenberg exchange coupling J obtained by a downfolding method in terms of the three band parameters is used to carry out an optimization analysis consistent with J from neutron scattering experiments for a series of cuprates. In addition, the effective one-band parameters U' and t' can be described using the three band parameters, thus revealing the hidden equivalence of the one-band and three-band models. The ground-state singlet weights obtained from an exact diagonalization elucidates the role of Zhang-Rice singlets in the equivalence. The results provide a consistent method to connect electronic parameters obtained from spectroscopy and the three-band model with values of J obtained from scattering experiments, band dispersion measurements and the effective one-band Hubbard model [1].

[1] K. Sheshadri, D. Malterre, A. Fujimori, and A. Chainani, Connecting the one-band and three-band Hubbard models of cuprates via spectroscopy and scattering experiments, Phys. Rev. B 107, 085125 (2023).