NiO: Correlated Bandstructure of a Charge-Transfer Insulator

TL;DR

This paper combines ab initio methods and dynamical mean-field theory to accurately compute the bandstructure of NiO, a charge-transfer insulator, resolving a longstanding theoretical challenge and revealing detailed low-energy features.

Contribution

It introduces a novel computational approach integrating ab initio and DMFT methods to accurately model NiO's bandstructure, including low-energy Zhang-Rice bands.

Findings

Excellent agreement with ARPES data

Identification of k-dependent orbital character in low-energy bands

Resolution of a long-standing problem in solid state theory

Abstract

The bandstructure of the prototypical charge-transfer insulator NiO is computed by using a combination of an {\it ab initio} bandstructure method and the dynamical mean-field theory with a quantum Monte-Carlo impurity solver. Employing a Hamiltonian which includes both Ni-d and O-p orbitals we find excellent agreement with the energy bands determined from angle-resolved photoemission spectroscopy. This solves a long-standing problem in solid state theory. Most notably we obtain the low-energy Zhang-Rice bands with strongly k-dependent orbital character discussed previously in the context of low-energy model theories.