Progress in the Development of Advanced Temperature-Dependent Free-Energy Density Functionals Beyond the Generalized Gradient Approximation

Recently, it has been shown that explicit dependence on temperature in the exchange-correlation (XC) free-energy density functional is important in density functional theory studies of warm dense matter [1]. As a first approximation, in the attempt to include thermal effects into XC, the finite-T KSDT local spin-density approximation functional was constructed by the analytical parametrization of the XC free energy of the homogeneous electron gas. Consequently, the non-empirical KDT16 [2] generalized gradient approximation (GGA) functional, which captures nonhomogeneity effects and shows better agreement with experiments, has been constructed. Here, we present recent progress in going beyond the GGA by developing finite-T extensions to the PBE0 and SCAN-L (the de-orbitalized version of SCAN) XC functionals. We present preliminary results for optical reflectivity of shocked CH and warm dense He.

1 V. V. Karasiev, L. Calderín, and S. B. Trickey, Phys. Rev. E 93, 063207 (2016).
2 V. V. Karasiev, J. W. Dufty, and S. B. Trickey, Phys. Rev. Lett. 120, 076401 (2018).