Electron vs. hole doping in infinite-layer nickelates: electronic structure, magnetism and correlations

The observation of superconductivity in undoped infinite-layer nickelates $R$NiO$_2$ ($R$ = rare earth) challenges our current understanding and calls for a re-examination of the underlying electronic structure of this family of materials. In this context, it is particularly important to extend the investigation of $R$NiO$_2$ compounds from the intensively studied hole-doped regime to the almost unexplored electron-doped one. Here, we use a combination of density-functional theory and dynamical mean-field theory to study the evolution of the electronic structure of infinite-layer nickelates in these two doping regimes. We find a striking asymmetry in the self-doping of the Ni-$d_{x^2-y^2}$ band due to the $R(5d)$ states: while this effect is strongly suppressed upon hole doping, electron doping instead leads to an increase in the size of the $R(5d)$ electron pockets, but without effectively hole-doping the Ni-$d_{x^2-y^2}$ band. This asymmetry has an important impact on the magnetic response as antiferromagnetism is rapidly suppressed upon hole doping, whereas it remains the ground state upon electron doping. Despite these differences, electronic correlations on both sides of the phase diagram are dominated by the Ni $d_{x^2-y^2}$ orbital, suggesting that a single-band description may be appropriate for infinite-layer nickelates in both the electron- and hole-doped regimes.