Full potential ab initio calculations of spiral spin density waves in fcc Fe

All ab initio calculations of spiral spin density waves heretofore have used the atomic sphere approximation (ASA) in which not only is the potential assumed spherical but also the direction of magnetization is taken constant within each Wigner-Seitz sphere. We have performed full potential local density approximation calculations for gamma-Fe spiral spin density waves with wave vector q=(2 pi/a)(0,0,alpha) and q=(2 pi/a)(gamma,0,1), finding the ground state at alpha approximate to 0.55. The results differ quantitatively but not qualitatively from those of ASA calculations. However, interesting results are obtained for the azimuthal angle of the magnetization phi(r)= 9.r+<(phi)over cap> (r), where e(+<(phi)over cap>(r)) is a function with the lattice periodicity which is calculated self-consistently. [S0163-1829(98)04738-9].