Voltage dependent spin tunneling and spin relaxation in spin-leds

Spin diodes are potential building blocks of spin transistors, themselves units for future spintronics “microchips” for quantum information processing. Ferromagnet-semiconductor Schottky diodes are useful model devices that allow for understanding of basic physical and electronic processes in transport of spin-polarized electrons across the interface between a conventional ferromagnet (itself a natural reservoir of spins) and a spin hospitable semiconductor like galliumarsenide (GaAs), where spin-carrying electrons can be used for quantum information processing. This paper will introduce a model that explains experimentally observed voltage dependence of finite spin transfer efficiency, using Schottky tunneling contact, and drift-diffusion equations. In the same framework we present a rate-equation based explanation for voltage dependent spin relaxation of hot electrons, which has also been experimentally observed in spin light emitting diodes (spin-LEDs). Based on this model, we present device suggestions that are realizable within the modern semiconductor growth and nanoprocessing R&D sector.