# Improved electronic structure and magnetic exchange interactions in transition metal oxides

## TL;DR

This paper demonstrates that the ACBN0 pseudo-hybrid Hubbard density functional provides accurate electronic structure and magnetic exchange interaction calculations for transition metal oxides at a computational cost comparable to standard DFT methods.

## Contribution

The study introduces and validates the ACBN0 functional as a fast, accurate, and parameter-free alternative to traditional DFT+U and hybrid methods for transition metal oxides.

## Key findings

- ACBN0 accurately predicts electronic properties of transition metal oxides.
- Results are in excellent agreement with hybrid functionals, GW, and experiments.
- ACBN0 is computationally efficient, comparable to standard DFT calculations.

## Abstract

We discuss the application of the Agapito Curtarolo and Buongiorno Nardelli (ACBN0) pseudo-hybrid Hubbard density functional to several transition metal oxides. ACBN0 is a fast, accurate and parameter-free alternative to traditional DFT+$U$ and hybrid exact exchange methods. In ACBN0, the Hubbard energy of DFT+$U$ is calculated via the direct evaluation of the local Coulomb and exchange integrals in which the screening of the bare Coulomb potential is accounted for by a renormalization of the density matrix. We demonstrate the success of the ACBN0 approach for the electronic properties of a series technologically relevant mono-oxides (MnO, CoO, NiO, FeO, both at equilibrium and under pressure). We also present results on two mixed valence compounds, Co$_3$O$_4$ and Mn$_3$O$_4$. Our results, obtained at the computational cost of a standard LDA/PBE calculation, are in excellent agreement with hybrid functionals, the GW approximation and experimental measurements.