Abstract:

The study of spin dephasing and relaxation processes is at the heart of semiconductor spintronics research. In the talk, I will give a brief introduction into optical orientation of spins in 2D semiconductor heterostructures and the relevant spin dephasing mechanisms. Then I will report on our time-resovled studies of spin dephasing in different types of systems: (a) [110]-grown quantum wells, where the symmetry of the structure strongly influences the spin dephasing, and (b) high-mobility [001]-grown quantum wells. In the [001] QWs, interesting many-body effects were observed by us that had been theoretically predicted by Wu et al. : the spin dephasing strongly depends on the initial spin polarization, and the temperature-dependence for large initial spin polarization is different from that observed for small initial spin polarization. Additionally, a large in-plane spin dephasing anisotropy is present in the [001]-grown quantum wells, which stems from the presence of both Rashba and Dresselhaus spin-orbit fields. The experimental data are in excellent agreement with calculations by Wu et al., and using these calculations, a long in-plane spin lifetime of several nanoseconds is predicted for the [001] QW.
 
 
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