Doping dependence of electronic structure of infinite-layer NdNiO2

TL;DR

This study uses advanced theoretical methods to explore how hole doping affects the electronic structure of NdNiO2, revealing complex orbital interactions and Fermi surface changes relevant to understanding its superconductivity.

Contribution

It provides a detailed theoretical analysis of doping effects on NdNiO2's electronic structure, highlighting orbital hybridization, Hund's rule influence, and Fermi surface evolution, which are novel insights.

Findings

Strong hybridization between Ni-3dx2-y2 and itinerant electrons

Non-monotonic electron occupation with doping

Fermi surface topology varies with doping level

Abstract

We investigate the electronic structure of nickelate superconductor NdNiO2 upon hole doping, by means of density-functional theory and dynamical mean-field theory. We demonstrate the strong intrinsic hybridization between strongly correlated states formed by Ni-3dx2-y2 orbital and itinerant electrons due to Nd-5d and Ni-3dz2 orbitals, producing a valence-fluctuating correlated metal as the normal state of hole-doped NdNiO2. The Hund's rule appears to play a dominating role on multi-orbital physics in the lightly doped compound, while its effect is gradually reduced by increasing the doping level. Crucially, the hole-doping leads to intricate effects on Ni-3d orbitals, such as a non-monotonic change of electron occupation in lightly doped level, and a flipping orbital configuration in the overdoped regime. Additionaly, we also map out the topology of Fermi surface at different doping levels. These findings render a preferred window to peek into electron pairing and superconductivity.