Fermi-L\"owdin orbital self-interaction correction using the strongly constrained and appropriately normed meta-GGA functional

TL;DR

This paper applies the Fermi-Lowdin Orbital Self-Interaction Correction to the SCAN meta-GGA functional, improving the accuracy of electronic property predictions by reducing self-interaction errors in density functional theory calculations.

Contribution

It introduces a size-extensive implementation of FLOSIC for SCAN, demonstrating improved results over uncorrected SCAN and other functionals for properties affected by self-interaction errors.

Findings

FLOSIC-SCAN outperforms FLOSIC-LDA and FLOSIC-PBE in most cases.

FLOSIC-SCAN yields better orbital energies and dissociation energies.

Using the FLOSIC-corrected density in SCAN improves total and atomization energies.

Abstract

Despite the success of density functional approximations (DFAs) in describing the electronic properties of many-electron systems, the most widely used approximations suffer from self-interaction errors (SIE) that limit their predictive power. Here we describe the effects of removing SIE from the strongly constrained and appropriately normed (SCAN) meta-generalized gradient approximation (GGA) using the Fermi-Lowdin Orbital Self-Interaction Correction (FLOSIC) method. FLOSIC is a size-extensive implementation of the Perdew-Zunger self-interaction correction (PZ-SIC) formalism. We find that FLOSIC-SCAN calculations require careful treatment of numerical details and describe an integration grid that yields reliable accuracy with this approach. We investigate the performance of FLOSIC-SCAN for predicting a wide array of properties and find that it provides better results than FLOSIC-LDA and FLOSIC-PBE in nearly all cases. It also gives better predictions than SCAN for orbital energies and dissociation energies where self-interaction effects are known to be important, but total energies and atomization energies are made worse. For these properties, we also investigate the use of the self-consistent FLOSIC-SCAN density in the SCAN functional and find that this DFA@FLOSIC-DFA approach yields improved results compared to pure, self-consistent SCAN calculations. Thus FLOSIC-SCAN provides improved results over the parent SCAN functional in cases where SIEs are dominant, and even when they are not, if the SCAN@FLOSIC-SCAN method is used.