Tuning of the Landé g-factor in AlxGa1−xAs/AlAs single and double quantum wells

We report on the spin dynamics of a high mobility two-dimensional electron gas in a AlxGa1−xAs/AlAs double quantum well structure. For high electron density samples, the gfactor was measured using time-resolved Kerr rotation technique. The g-factor tuning capability was observed by changing the aluminum content x independently in each well. Experiments demonstrated an unusual spin dephasing time robustness for high excitation power. The effect of the interaction between wells was analyzed in samples with different tunneling barriers. Results were compared with experiments on single well systems demonstrating higher spin polarization generation, longer spin dephasing time, and coupling for the double structures.