Electronic Structure across the Rare-Earth Series in Superconducting Infinite Layer Nickelates*

The exciting discovery of superconductivity in oxygen-reduced monovalent nickelates has raised a new platform for the study of unconventional superconductivity, with similarities and differences to the cuprate high temperature superconductors. General trends appear in the infinite nickelates RNiO2 with rare-earths R spanning across the Lanthanides. The role of oxygen charge transfer diminishes in comparison to the cuprates, with an increased and prominent role played by rare-earth 5d electrons near the Fermi level when traversing from La to Lu. A decrease in lattice volume indicates that the magnetic exchange additionally grows, which may be favorable for superconductivity. However, compensation effects from the itinerant 5d electrons presents a close analogy to Kondo or Anderson lattices, indicating a more complex interplay between charge transfer, bandwidth renormalization, compensation, and magnetic exchange.