Symmetrised method for the calculation of the band structure of noncollinear magnets

Abstract

The one-electron Schrodinger equation for a noncollinear magnet (NCM) with arbitrary direction of atomic spin in the magnetic unit cell (MUC) is presented. By analogy with the usual KKR method the secular equation for an NCM is deduced. The symmetry of the problem is discussed on the basis of spin space groups. It is shown that the symmetry consideration often leads to the secular equation factorising anywhere in the Brillouin zone. The calculation of the electron spectrum of the spin spiral for BCC Fe has been carried out and the calculated energy of the spin wave is in good agreement with the experimental value.