  GdN bulk is studied with the local density approximation, on the Hartree-Fock
level, and on the level of the hybrid functional B3LYP. A local basis set
formalism is used, as implemented in the present CRYSTAL06 release. It is
demonstrated that the code is technically capable of treating this system with
its 4f electrons explicitly, i.e. out of the core. The band structure at the
level of the local density approximation is in good agreement with earlier
calculations and is found to be half-metallic. The Hartree-Fock band structure
is insulating with a large gap. Interestingly, three solutions were found at
the B3LYP level. The lowest of them is insulating for majority spin, and the
Fermi surface for minority spin consists only of points, resulting in a very
low density of states around the Fermi level.

Materials Science