Spin relaxation in semiconductor quantum dots

We have studied spin-flip processes in GaAs electron quantum dots that acco mpany transitions between different discrete energy levels. Several differe nt mechanisms that originate from spin-orbit coupling are shown to be respo nsible for such processes. We have evaluated the rates for all mechanisms w ith and without. a magnetic field. We have shown that the spin relaxation o f the electrons localized in the dots differs strikingly from that of the d elocalized electrons. The most effective spin-flip mechanisms related to th e absence of the inversion symmetry appear to be strongly suppressed for lo calized electrons. This results in unusually low spin-hip rates.