Relativistic spin-polarized single-site scattering theory

Relativistic spin-polarized scattering theory is discussed and the relevant radial Dirac equations for an electron in a potential with a magnetic field component are derived. The full solution to the coupled Dirac equations treating spin-orbit coupling and spin polarization on an equal footing is found and, by matching these wavefunctions at the muffin-tin radius, the scattering amplitudes and phase shifts are calculated. The interpretation of these results gives a pictorial view of the interplay between spin-orbit coupling and spin polarization. New coupling between states is observed due to the removal of previously used approximations. The magnitude of this coupling throws doubt on some earlier calculations of magnetocrystalline anisotropy energies. A scattering analogue to the generalized Zeeman effect is also described.