  An new and accurate scheme to calculate the interatomic Dzyaloshinskii-Moriya
interaction (DMI) parameters is presented, which is based on the fully
relativistic Korringa-Kohn-Rostoker Green function (KKR-GF) technique.
Corresponding numerical results are compared with those obtained using other
schemes reported in the literature.
  The differences found can be attributed primarily to the different reference
states used in the various approaches. In addition an expression for the DMI
parameters formulated for a micromagnetic model Hamiltonian is presented that
provides a connection to the DMI parameters calculated for atomistic
Hamiltonians. This formulation also allows the discussion of the DMI in terms
of specific features of the electronic band structure.
