Pseudopotential and full-electron DFT calculations of thermodynamic properties ofelectrons in metals and semiempirical equations of state

Abstract

In the present work, we compare the thermal contribution of electrons to thermodynamicfunctions of metals in different models at high densities and electron temperatures. One ofthe theoretical approaches, the full-potential linear-muffin-tin-orbital method, treats allelectrons in the framework of density functional theory (DFT). The other approach,VASP, uses projector-augmented-wave pseudopotentials for the core electronsand considers the valent electrons also in the context of DFT. We analyze thelimitations of the pseudopotential approach and compare the DFT results with afinite-temperature Thomas–Fermi model and two semiempirical equations of state.