Fermi surface and helical spin ordering in Eu metal

The band structure and Fermi surface of the b.c.c. Eu metal have been calculated by the non-relativistic KKR method. The obtained Fermi surface is grossly similar to that of Anderson and Loucks (Phys. Rev., 167:551 (1968)). Essential differences are indicated. The electron surface around H is shaped like a sphere with eight low moulds in eight directions near the HP-axes (called 'bumpy sphere'). The hole surface around P is shaped like a 'rounded-off cube', as was obtained by Andersen and Loucks, but the cross-section perpendicular to the HP-axis for the tetrahedrally located wing (or island) is shaped like a 'truncated-triangle', not like an ellipse. The helical spin ordering at low temperatures can be understood on the basis of the hole Fermi surface. The electron surface around H does not seem to concern the nesting. Some other phenomena are also considered briefly. (author)