Interlayer Exchange Coupling in (MnTe)_m (ZnTe)_n Superlattices

The interlayer exchange coupling mediated by the valence band electrons in $\textrm{(MnTe)}_{\textrm{m}} \textrm{(ZnTe)}_{\textrm{n}}$ superlattices has been examined theoretically. The calculations have been performed within the framework of three dimensional tight binding model. Both types of magnetic configurations in the superlattice, resulting from zinc-blende MnTe real magnetic structure, have been considered. The total energy calculations have revealed much faster decrease of the coupling strength with nonmagnetic spacer thickness than that observed in NaCl structures. In addition a new feature -- nonmonotonic character of that decrease -- has been found.