Symmetry aspects in spin-polarized relativistic electronic structure calculations based on the Green function method

The consideration of spin-orbit coupling in spin-polarized electronic structure calculations leads to magnetic anisotropies and reduces the symmetry of the problem. The theory of magnetic groups is required to make full use of the remaining symmetry. A systematic method is presented to treat this problem in the framework of the Green function method. An application to the magnetocrystalline anisotropy energy of Fe fails to converge numerically but reveals where this effect originates as a function of reciprocal space vector and energy.