Hybridization and correlation effects in the electronic structure of infinite-layer nickelates

We combine density functional theory and dynamical mean field theory to study the electronic structure of infinite-layer nickelate NdNiO₂. Without considering correlation effects on Ni, we find adjacent NiO₂ planes are coupled by a metallic Nd spacer layer. However, the largest hybridization between Ni-d_x2-y2 state and itinerant electrons origins from an interstitial-s orbital instead of Nd-d orbitals. Correlation effects on Ni reduces the hybridization between Ni-d_x2-y2 state and itinerant electrons and when sufficiently strong, they can open a Mott gap, which is separated by the lower Hubbard band of Ni-d_x2-y2 state and hybridization states (interstitial-s and Nd-d orbitals). With correlation strength increasing, antiferromagnetic ordering occurs before the metal-insulator transition. Experimentally long-range magnetic order has not been observed in NdNiO₂. This places NdNiO₂ in a paramagnetic metallic phase in which the hybridization between Ni-d_x2-y2 and itinerant electrons is non-negligible and Ni correlation strength is moderate.