Abstract:

We consider the spin injection from Fe into ZnSe and GaAs in the ballistic limit. By means of the ab initio screened Korringa-Kohn-Rostoker method we calculate the ground-state properties of epitaxial Fe\textbackslash{}ZnSe(001) and Fe\textbackslash{}GaAs(001) heterostructures. Three injection processes are considered: injection of hot electrons and injection of ``thermal{''} electrons with and without an interface barrier. The calculation of the conductance by the Landauer formula shows that these interfaces act like a nearly ideal spin filter, with spin polarization as high as 99%. This can be traced back to the symmetry of the band structure of Fe for normal incidence.