Electronic entanglement in late transition metal oxides

TL;DR

This paper investigates electronic entanglement in late transition metal monoxides using advanced computational methods, revealing complex entanglement patterns influenced by crystal field effects and Coulomb interactions.

Contribution

It introduces a combined LDA+DMFT approach with Exact Diagonalization to quantitatively analyze electronic entanglement in transition metal oxides, providing new insights into their many-body states.

Findings

Entanglement varies significantly across MnO, FeO, CoO, NiO.

Crystal field and Coulomb interactions jointly influence entanglement complexity.

Electronic excitation spectra match experimental photoemission data.

Abstract

Here we present a study of the entanglement in the electronic structure of the late transition metal monoxides - MnO, FeO, CoO, and NiO - obtained by means of density-functional theory in the local density approximation combined with dynamical mean-field theory (LDA+DMFT). The impurity problem is solved through Exact Diagonalization (ED), which grants full access to the thermally mixed many-body ground state density operator. The quality of the electronic structure is affirmed through a direct comparison between the calculated electronic excitation spectrum and photoemission experiments. Our treatment allows for a quantitative investigation of the entanglement in the electronic structure. Two main sources of entanglement are explicitly resolved through the use of a fidelity based geometrical entanglement measure, and additional information is gained from a complementary entropic entanglement measure. We show that the interplay of crystal field effects and Coulomb interaction causes the entanglement in CoO to take a particularly intricate form.