Relativistic full-potential multiple scattering theory: An ab initio method and its applications

The Green function plays an essential role in the Kohn-Korringa-Rostocker (KKR) multiple scattering method. In practice, it is constructed from the regular and irregular solutions of the local Kohn-Sham equation and robust methods exist for spherical potentials. However, when applied to a non-spherical potential, numerical errors from the irregular solutions give rise to pathological behaviors of the charge density at small radius. Here we present a full-potential implementation of the relativistic KKR method to perform \textit{ab initio} self-consistent calculation by directly solving the Dirac differential equations. The pathology around the origin is completely eliminated with the help of an efficient pole-searching technique. This method is utilized to investigate the crystal structures of polonium and their bulk properties. The noble metals are also calculated, both as a test of our method and to study the relativistic effects.