Low-Threshold Pure-Circular Polarization Electro-Luminescence From Spin-Light-Emitting Diodes Consisting Of Oxidized Al/Alas Tunnel Barriers

We report lateral-type, GaAs/AlGaAs double hetero-structure (DH) spin-LEDs with stripe Fe spin injectors that exhibit nearly pure circular polarization (CP) electroluminescence (EL) with current densities of J similar to 10 A/cm(2) or less. Experiments with such spin-LEDs have made it possible to obtain experimental data that were not accessible in the first report [1,2]: namely, clear experimental proof for the presence of a threshold J value at which the annihilation of minority-helicity CP-EL component takes place.