Improving the applicability of the Pauli kinetic energy density based semilocal functional for solids

TL;DR

This paper introduces a revised MGGAC exchange-correlation functional, named rMGGAC, which improves the accuracy and robustness of solid-state property predictions by refining the correlation energy component based on the Pauli kinetic energy density.

Contribution

The paper proposes a new correlation energy functional for MGGAC, enhancing its performance for solids, especially in high and low-density regimes, and demonstrates its improved predictive capabilities.

Findings

Significant improvement in structural properties of solids.

Enhanced energetic property predictions.

Better performance in high and low-density limits.

Abstract

The Pauli kinetic energy enhancement factor $\alpha=(\tau-\tau^W)/\tau^{unif}$ is an important density ingredient, used to construct many meta-generalized gradient approximations (meta-GGA) exchange-correlation (XC) energy functionals, including the very successful strongly constrained and appropriately normed (SCAN) semilocal functional. Another meta-GGA functional, known as MGGAC [Phys. Rev. B 100, 155140 (2019)], is also proposed in recent time depending only on the $\alpha$ ingredient and based on the generalization of the Becke-Roussel approach with the cuspless hydrogen exchange hole density. The MGGAC functional is proved to be a very useful and competitive meta-GGA semilocal functional for electronic structure properties of solids and molecules. Based on the successful implication of the ingredient $\alpha$, which is also useful to construct the one-electron self-interaction free correlation energy functional, here we propose revised correlation energy for MGGAC exchange functional which is more accurate and robust, especially for the high and low-density limits of the uniform density scaling. The present XC functional, named as revised MGGAC (rMGGAC), shows an impressive improvement for the structural and energetic properties of solids compared to its previous version. Moreover, the assessment of the present constructed functional shows to be quite useful in solid-state physics in terms of addressing several current challenging solid-state problems.