Spin-controlled LEDs and VCSELs

Two different concepts for transferring spin-optoelectronics to practical room temperature operation devices are explained. First, electrical spin injection in the absence of an external magnetic field and up to room temperature is demonstrated for the first time using Fe/Tb-multilayers as Schottky-injectors on common LED-strucrures. Complete switching of the polarization from one orientation to the opposite is feasible within ±0.3 T. Second, the amplification of spin-information in vertical-cavity surface-emitting lasers (VCSELs) is demonstrated by optical test experiments. The output polarization of the VCSEL is unambiguously controlled by the polarized optical excitation. Furthermore, only a spin polarization degree of 30% for the electrons in the active region is required to generate a 100% polarized emission at room temperature for both pulsed and continuous optical excitation. Finally, we suggest a combination of both concepts in an electrically pumped spin-VCSEL.