[en] The authors examine theoretically conduction processes near the Fermi energy of thin layers of zincblende structure half metals, using as an example a superlattice consisting of monolayers of GaAs and MnAs, a bilayer of CrAs, and a bilayer of GaAs. By artificially separating bilayers, they show that non-fourfold coordinated Cr states thwart half metallicity. However, capping the metal-As bilayers restores half metallicity and ballistic conduction of electrons around 0.3 eV above the Fermi level will give nearly 100% spin-polarized transmission in the direction of the thin superlattice. Recent developments suggest atomic layer epitaxy can be used to produce such thin layers for spintronics applications