On the spin-flip mechanisms of electrons in semiconductor quantum wells

We have studied the temperature dependence of the spin-flip processes of el ectrons in p-type modulation-doped GaAs quantum wells. We have found that a t low temperature (T less than or equal to 30 K) the exchange interaction b etween electrons and holes is the main mechanism responsible for the spin-n ip of the electrons, whereas at higher temperatures the so-called Dyakonov- Perel mechanism dominates. Furthermore, we have found that the recombinatio n time increases considerably with increasing lattice temperature from a va lue of tau(r) approximate to 200 ps at 5 K to tau(r) approximate to 400 ps at 60 K.