Optical detection of spin relaxation of 2D electrons during photoexcitation
Zhitomirskii V. E. , Kirpichev V. E., Filin A. I. , Timofeev V. B., Shepel' B. N., von Klitzing K.
Direct optical detection of the relaxation of the spin orientation of 2D electrons in a quantizing magnetic field has been achieved under conditions such that the corrections for the exchange interaction of the spins of an electron spin and a photoexcited hole are reduced to zero. This is the first such detection. The time scale of the relaxation to a spin equilibrium has been found through time-resolved measurements to be on the order of 5 ns in a field of 2.6 T. The spin relaxation slows down as the index of the Landau level decreases and as the magnetic field simultaneously increases. The experimental results point to spin-flip mechanisms involving a spin-orbit interaction.