Long exciton spin relaxation in coupled quantum wells

Kowalik-Seidl, K.; Vögele, X. P.; Rimpfl, B. N.; Manus, S.; Kotthaus, J. P.; Schuh, D.; Wegscheider, W.; Holleitner, A. W.
July 2010
Applied Physics Letters;7/5/2010, Vol. 97 Issue 1, p011104
Academic Journal
Spatially indirect excitons in a coupled quantum well structure were studied by means of polarization and time-resolved photoluminescence. A strong degree of circular polarization (>50%) in emission was achieved when the excitation energy was tuned into resonance with the direct exciton state. The indirect transition remained polarized several tens of nanoseconds after the pumping laser pulse, demonstrating directly a very long relaxation time of exciton spin. The observed spin relaxation time exceeds the radiative lifetime of the indirect excitons.


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