High-throughput determination of Hubbard U and Hund J values for transition metal oxides via linear response formalism

TL;DR

This paper presents a high-throughput linear response method to accurately determine Hubbard U and Hund J parameters for transition metal oxides, enabling improved DFT+U calculations for over 2000 compounds.

Contribution

It develops an automated workflow for calculating U and J values on supercomputers and applies it to a large set of transition metal oxides, demonstrating its effectiveness.

Findings

U and J values significantly influence magnetic properties.

Including O-p U improves lattice parameter predictions.

Workflow enables rapid, accurate parameter determination for large datasets.

Abstract

DFT+U provides a convenient, cost-effective correction for the self-interaction error (SIE) that arises when describing correlated electronic states using conventional approximate density functional theory (DFT). The success of a DFT+U(+J) calculation hinges on the accurate determination of its Hubbard U and Hund's J parameters, and the linear response (LR) methodology has proven to be computationally effective and accurate for calculating these parameters. This study provides a high-throughput computational analysis of the U and J values for transition metal d-electron states in a representative set of over 2000 magnetic transition metal oxides (TMOs), providing a frame of reference for researchers who use DFT+U to study transition metal oxides. In order to perform this high-throughput study, an atomate workflow is developed for calculating U and J values automatically on massively parallel supercomputing architectures. To demonstrate an application of this workflow, the spin-canting magnetic structure and unit cell parameters of the multiferroic olivine LiNiPO4 are calculated using the computed Hubbard U and Hund J values for Ni-d and O-p states, and are compared with experiment. Both the Ni-d U and J corrections have a strong effect on the Ni-moment canting angle. Additionally, including a O-p U value results in a significantly improved agreement between the computed lattice parameters and experiment.