Spin-LED enable almost purely circularly polarized emission

Researchers from the Tokyo Institute of Technology managed to achieve an almost purely circularly polarized (CP) electroluminescence (EL) in spin-polarized LEDs at room temperature without an external magnetic field.

Spin-LED design and images (Tokyo Institute of Technology)

The researchers used LEDs and a polycrystalline Fe in-plane spin injector. During the experiment the researchers injected spins of a given type, which were dispersed due to spin relaxation. Radiative recombination subsequently occurred, which was observed in the form of a linearly polarized emission. Almost pure circularly polarized emission was achieved when the current density was high enough.