Long spin memory times and flipping features in GaAs: the hyperfine coupling effect
The flipping of optically generated spins in GaAs was investigated using pump probe photoluminescence polarization measurements in the presence of an external magnetic field (B) applied perpendicularly to the spins. The spin polarization (PS) was found to decay with the time delay. The observed PS decay rates correspond to the spin-flip times. A featurable spin flipping was observed. The spin-flip (spin memory) times are longest at low lattice temperature and high B, and times up to 1.5 s were observed. However, a field higher than 4T saturates the spin-flip times. The results are discussed based on the hyperfine coupling effect.
Optics and Photonics Letters
Photonics, Optoelectronics and Optical Communications