Influence of $f$ Electrons on the Electronic Band Structure of Rare-Earth Nickelates

TL;DR

This paper investigates how $f$ electrons influence the electronic band structure of rare-earth nickelates, highlighting their significant role in the material's electronic properties and implications for superconductivity.

Contribution

It demonstrates that $f$ electrons affect the electronic structure of NdNiO$_{2}$, regardless of their energy position, and discusses the impact of electron correlations on these states.

Findings

Lattice parameters match experimental data across different parameters.

Increasing Coulomb interaction $U$ shifts $f$ states away from the Fermi level.

$f$ states significantly modify the electronic band structure and effective models.

Abstract

Recently, superconductivity was discovered in the infinite layer of hole-doped nickelates NdNiO$_{2}$. Contrary to this, superconductivity in LaNiO$_{2}$ is still under debate. This indicates the crucial role played by the $f$ electrons on the electronic structure and the pairing mechanism of infinite-layer nickelates. Here we discuss the role of the electron correlations on the $f$ electron states and their influence on the electronic structure. We show that the lattice parameters are in good agreement with the experimental values, independent of the chosen parameters within the DFT+$U$ approach. Increasing Coulomb interaction $U$ tends to shift the $f$ states away from the Fermi level. Surprisingly, independently of the position of $f$ states with respect to the Fermi energy, these states play an important role in the electronic band structure, which can be reflected in the modification of the NdNiO$_{2}$ effective models.