Electronic structure of nickelates: From two-dimensional heterostructures to three-dimensional bulk materials

TL;DR

This paper investigates the electronic structure of nickelates, modeling the transition from two-dimensional heterostructures to three-dimensional bulk materials, highlighting the effects of electronic correlations and magnetic tendencies.

Contribution

It introduces a simple two-band model for nickelate heterostructures and extends it to three dimensions, analyzing correlation effects with dynamical mean-field theory.

Findings

Electronic correlations are similar in 2D and 3D, but stronger in 3D for Mott insulating behavior.

Quantitative differences in interaction strength needed for insulating states.

Strong antiferromagnetic tendencies in the derived spin-orbital model.

Abstract

Reduced dimensionality and strong electronic correlations, which are among the most important ingredients for cupratelike high-Tc superconductivity, characterize also the physics of nickelate-based heterostructures. Starting from the local-density approximation we arrive at a simple two-band model for quasi-two-dimensional 2D LaNiO3 /LaAlO3 heterostructures and extend it by introducing an appropriate hopping in the z direction to describe the dimensional crossover to three dimensions 3D. Using dynamical mean-field theory, we study the effects of electronic correlations with increasing interaction strength along the crossover from 2D to 3D. Qualitatively, the effects of electronic correlations are surprisingly similar, albeit quantitatively larger interaction strengths are required in three dimensions for getting a Mott-Hubbard insulating state. The exchange parameters of an effective Kugel-Khomskii-type spin-orbital model are also derived and reveal strong antiferromagnetic tendencies.