Electronic structure of rare-earth infinite-layer ReNiO2 (Re=La, Nd)

TL;DR

This paper investigates the electronic structures of LaNiO2 and NdNiO2 using first-principles calculations, revealing differences in orbital hybridization and band features that are crucial for understanding their superconducting properties.

Contribution

It provides a detailed comparison of the electronic structures of LaNiO2 and NdNiO2, highlighting the role of Nd-f orbitals in the latter, which was not previously well understood.

Findings

LaNiO2 exhibits a single band feature with weak hybridization.

NdNiO2 shows significant hybridization between Nd-f and Ni-dx2-y2 orbitals.

Band structures suggest new characteristics relevant to superconductivity.

Abstract

The discovery of infinite layer nickelate superconductor marks the new era in the field of superconductivity. In the rare-earth (Re) nickelates ReNiO2, although the Ni is also of d9 electronic configuration, analogous to Cu d9 in cuprates, whether electronic structures in infinite-layer nickelate are the same as cuprate and possess the single band feature as well are still open questions. To illustrate the electronic structure of rare-earth infinite-layer nickelate, we perform first principle calculations of LaNiO2 and NdNiO2 compounds and compare them with that of CaCuO2 using hybrid functional method together with Wannier projection and group symmetry analysis. Our results indicate that the Ni-dx2-y2 in the LaNiO2 has weak hybridization with other orbitals and exhibits characteristic single band feature, whereas in NdNiO2, the Nd-f orbital hybridizes with Ni-dx2-y2 and is a non-negligible ingredient for transport and even high-temperature superconductivity. Given that the Cu-dx2-y2 in cuprate strongly hybridizes with O-2p, the calculated band structures of nickelate imply some new band characters which is worth to gain more attentions.