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

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 (2019 Phys. Rev. B 100 155140), 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.

Automated summary

The importance of the Pauli kinetic energy enhancement factor alpha in constructing meta-GGA exchange-correlation energy functionals is discussed, along with the proposal of the MGGAC functional and its revised correlation energy. The successful implication of the alpha ingredient leads to significant improvements in solid structural and energetic properties, demonstrating usefulness in addressing current challenging solid-state problems.