Fully thermal meta-GGA exchange correlation free-energy density functional

Warm dense matter (WDM) is the materials regime that bridges condensed matter and plasmas that occurs in giant-planet centers and the state trajectory of inertial confinement fusion experiments. Predictive density functional theory simulations of WDM must use an explicitly temperature-dependent free-energy exchange-correlation functional. Incorporating thermal effects at the meta-GGA level of refinement, the newly developed fully thermal fTSCAN functional provides high accuracy across the entire temperature and pressure range from ambient to extreme conditions. Tests on model systems highlight the contributions of thermal and density inhomogeneity effects, while molecular dynamics simulations demonstrate accuracy for materials ranging from water under ambient conditions to dense hydrogen at a wide range of temperatures.