Spin injection through an Fe/InAs interface

The spin dependence of the interface resistance between ferromagnetic Fe and InAs is calculated from first principles for specular and disordered (001) interfaces. Because of the symmetry mismatch in the minority-spin channel, the specular interface acts as an efficient spin filter with a transmitted current polarization between 98% and 89%. The resistance of a specular interface in the diffusive regime is comparable to the resistance of a few microns of bulk InAs. Symmetry breaking arising from interface disorder reduces the spin asymmetry substantially, and we conclude that efficient spin injection from Fe into InAs can only be realized using high-quality epitaxial interfaces.