Quasiparticle bands in cuprates by quantum chemical methods: towards an ab initio description of strong electron correlations

TL;DR

This paper introduces an ab initio multiconfiguration approach to accurately model strong electron correlations in cuprates, successfully reproducing experimental band dispersions and Fermi surface evolution.

Contribution

It presents a novel first-principles multiconfiguration method explicitly including Cu 3d and O 2p electrons, advancing the ab initio study of strongly correlated Mott insulators.

Findings

Reproduces photoemission band dispersion with high accuracy

Captures Fermi surface evolution with doping from first principles

Explicitly considers Zhang-Rice band and nonlocal spin effects

Abstract

Realistic electronic-structure calculations for correlated Mott insulators are notoriously hard. Here we present an ab initio multiconfiguration scheme that adequately describes strong correlation effects involving Cu 3d and O 2p electrons in layered cuprates. In particular, the O 2p states giving rise to the Zhang-Rice band are explicitly considered. Renormalization effects due to nonlocal spin interactions are also treated consistently. We show that the dispersion of the lowest band observed in photoemission is reproduced with quantitative accuracy. Additionally, the evolution of the Fermi surface with doping follows directly from our ab initio data. Our results thus open a new avenue for the first-principles investigation of the electronic structure of correlated Mott insulators.