Multiorbital Processes Rule the Nd_{1-x}Sr_{x}NiO_{2} Normal State

Abstract

The predominant Ni-multiorbital nature of infinite-layer neodynium nickelate at stoichiometry and with doping is revealed. We investigate the correlated electronic structure of NdNiO_{2} at lower temperatures and show that first-principles many-body theory may account for Kondo(-lattice) features. Yet, those features are not only based on localized Ni-d_{x^{2}-y^{2}} and a Nd-dominated self-doping band, but they heavily build on the participation of Ni-d_{z^{2}} in a Hund-assisted manner. In a tailored three-orbital study, the half-filled regime of the former in-plane Ni orbital remains surprisingly robust even for substantial hole doping δ. Reconstructions of the interacting Fermi surface designate the superconducting region within the experimental phase diagram. Furthermore, they provide clues to recent Hall measurements, as well as to the astounding weakly insulating behavior at larger experimental δ. Finally, a strong asymmetry between electron and hole doping, with a revival of Ni single-orbital features in the former case, is predicted. Unlike cuprates, superconductivity in Nd_{1-x}Sr_{x}NiO_{2} is of distinct multiorbital kind, building up on nearly localized Ni-d_{x^{2}-y^{2}} and itinerant Ni-d_{z^{2}}.