R. Singer

Construction of basis functions with crystal symmetry for the spin-cluster expansion of the magnetic energy on the atomic scale

For a crystal with symmetry according to a space-group G, a set of linearly independent and orthogonal basis functions for the spin-cluster expansion of the magnetic energy on the atomic scale is constructed, which is invariant under the action of each g∈G. This basis set is found by linear combinations of the basis functions invariant under global rotations of the magnetic moments, as defined in a former paper [R. Singer and M. Fahnle, J. Math. Phys. 47, 113503 (2006)10.1063/1.2364181].