Pure circular polarization electroluminescence at room temperature with spin-polarized light-emitting diodes.
We report the room-temperature electroluminescence (EL) with nearly pure circular polarization (CP) from GaAs-based spin-polarized light-emitting diodes (spin-LEDs). External magnetic fields are not used during device operation. There are two small schemes in the tested spin-LEDs: first, the stripe-laser-like structure that helps intensify the EL light at the cleaved side walls below the spin injector Fe slab, and second, the crystalline AlOxspin-tunnel barrier that ensures electrically stable device operation. The purity of CP is depressively low in the low current density (J) region, whereas it increases steeply and reaches close to the pure CP whenJ> 100 A/cm2There, either right- or left-handed CP component is significantly suppressed depending on the direction of magnetization of the spin injector. Spin-dependent reabsorption, spin-induced birefringence, and optical spin-axis conversion are suggested to account for the observed experimental results.
Laboratory for Future Interdisciplinary Research of Science and Technology, Tokyo Institute of Technology, 4259-J3-15 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.
Nozomi
0000-0002-7292-0282
N
Nishizawa
Laboratory for Future Interdisciplinary Research of Science and Technology, Tokyo Institute of Technology, 4259-J3-15 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.
Kazuhiro
K
Nishibayashi
Laboratory for Future Interdisciplinary Research of Science and Technology, Tokyo Institute of Technology, 4259-J3-15 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan munekata.h.aa@m.titech.ac.jp.
Hiro
0000-0003-1757-058X
H
Munekata
circular polarization; nonlinear effect; semiconductors; spin injection; spintronics