Spin-orbit coupling with ultrasoft pseudopotentials: Application to Au and Pt

We show how to include the spin-orbit coupling in electronic structure calculations of crystalline solids based on plane waves and ultrasoft pseudopotentials. The spin-orbit split electronic band structures of fcc-Au and of fcc-Pt are calculated by fully relativistic pseudopotentials derived from an atomic Dirac-like equation. The results are compared with accurate all-electron calculations available in the literature.