Electronic structure of the two-dimensional Heisenberg antiferromagnet VOCl: a multi-orbital Mott insulator

TL;DR

This study investigates the electronic structure of VOCl, revealing its reduced one-dimensionality and confirming it as a multi-orbital Mott insulator through combined experimental and theoretical analysis.

Contribution

It provides the first comprehensive analysis of VOCl's electronic structure, highlighting its multi-orbital Mott insulating nature and contrasting its properties with related compounds.

Findings

VOCl has reduced one-dimensionality compared to TiOCl and TiOBr.

VOCl is classified as a multi-orbital Mott insulator.

Density functional theory describes VOCl's electronic structure better than in titanium compounds.

Abstract

We have studied the electronic structure of the two-dimensional Heisenberg antiferromagnet VOCl using photoemission spectroscopy and density functional theory including local Coulomb repulsion. From calculated exchange integrals and the observed energy dispersions we argue that the degree of one-dimensionality regarding both the magnetic and electronic properties is noticeably reduced compared to the isostructural compounds TiOCl and TiOBr. Also, our analysis provides conclusive justification to classify VOCl as a multi-orbital Mott insulator. In contrast to the titanium based compounds density functional theory here gives a better description of the electronic structure. However, a quantitative account of the low-energy features and detailed line shapes calls for further investigations including dynamical and spatial correlations.