Comparative many-body study of Pr4Ni3O8 and NdNiO2

We study the many-body electronic structure of the stoichiometric and electron-doped trilayer nickelate Pr4Ni3O8 in comparison to that of the stoichiometric and hole-doped infinite layer nickelate NdNiO2 within the framework of density functional plus dynamical mean field theory, noting that Pr4Ni3O8 has the same nominal carrier concentration as NdNiO2 doped to a level of 1/3 holes/Ni. We find that the correlated Ni-3d shells of both of these low valence nickelates have similar many-body configurations with correlations dominated by the d(x2-y2) orbital. Additionally, when compared at the same nominal carrier concentration, the materials exhibit similar many-body electronic structures, self energies, and correlation strengths, but differ in Fermiology. Compared to cuprates, these materials are closer to the Mott-Hubbard regime due to their larger charge transfer energies. Moreover, doping involves the charge reservoir provided by the rare earth 5d electrons, as opposed to cuprates where it is realized via the oxygen 2p electrons.