The electronic structure of NaIrO$_3$, Mott insulator or band insulator?

TL;DR

This paper investigates the electronic structure of NaIrO$_3$ and finds that its insulating behavior can be explained either as a renormalized band insulator or a Mott insulator, with the former being more likely for realistic parameters.

Contribution

The study applies a combined local density approximation and Gutzwiller method to analyze the phase diagram of NaIrO$_3$, revealing the dominant insulator mechanism under realistic conditions.

Findings

NaIrO$_3$ can be a band insulator or Mott insulator depending on parameters.

Realistic parameters favor the renormalized band insulator scenario.

The phase diagram shows a transition driven by Coulomb interaction and spin-orbit coupling.

Abstract

Motivated by the unveiled complexity of nonmagnetic insulating behavior in pentavalent post-perovskite NaIrO$_3$, we have studied its electronic structure and phase diagram in the plane of Coulomb repulsive interaction and spin-orbit coupling (SOC) by using the newly developed local density approximation plus Gutzwiller method. Our theoretical study proposes the metal-insulator transition can be generated by two different physical pictures: renormalized band insulator or Mott insulator regime. For the realistic material parameters in NaIrO$_3$, Coulomb interaction $U=2.0 (J=U/4)$ eV and SOC strength $\eta=0.33$ eV, it tends to favor the renormalized band insulator picture as revealed by our study.