Reduction Of Spin Injection Efficiency by Interface Spin Scattering

We report the first experimental demonstration that interface microstructure limits diffusive electrical spin injection efficiency across heteroepitaxial interfaces. A theoretical treatment shows that the suppression of spin injection due to interface defects follows directly from the contribution of the defect potential to the spin-orbit interaction, resulting in enhanced spin-flip scattering. An inverse correlation between spin-polarized electron injection efficiency and interface defect density is demonstrated for ZnMnSe/AlGaAs-GaAs spin-LEDs with spin injection efficiencies of 0 to 85%.