Spatially resolved spin-injection probability for gallium arsenide

We report a Large spin-polarized current injection from a ferromagnetic met al into a nonferromagnetic semiconductor, at a temperature of 100 Kelvin. T he modification of the spin-injection process by a nanoscale step edge was observed. On flat gallium arsenide [GaAs(110)] terraces, the injection effi ciency was 92%, whereas in a 10-nanometer-wide region around a [(1) over ba r 11]-oriented step the injection efficiency is reduced by a factor of 6. A lternatively, the spin-relaxation Lifetime was reduced by a factor of 12. T his reduction is associated with the metallic nature of the step edge. This study advances the realization of using both the charge and spin of the el ectron in future semiconductor devices.