Benchmarking exchange-correlation functionals in the spin-polarized inhomogeneous electron gas under warm dense conditions
Zhandos A. Moldabekov, Tobias Dornheim, Jan Vorberger, Attila Cangi
Abstract
Warm dense matter is a highly active research area both at the frontier and interface of material science and plasma physics. We assess the performance of the commonly used exchange-correlation (XC) approximation (LDA, PBE, PBEsol, and AM05) in the spin-polarized inhomogeneous electron gas under warm dense conditions based on exact path-integral quantum Monte Carlo calculations. This extends our recent analysis on the relevance of inhomogeneities in the spin-unpolarized warm dense electron gas [Moldabekov et al., J. Chem. Phys. 155, 124116 (2021)]. We demonstrate that the predictive accuracy of these XC functionals deteriorates with (1) a decrease in density (corresponding to an increase in the interelectronic correlation strength) and (2) an increase of the characteristic wave number of the density perturbation. We provide recommendations for the applicability of the considered XC functionals at conditions typical for warm dense matter. Furthermore, we hint at future possibilities for constructing more accurate XC functionals under these conditions.