Spin dynamics and spin-dependent interactions in semiconductor heterostructures

We present new aspects on the spin dynamics of carriers and excitons in sem iconductor heterostructures. In doped wells, we show that the two spin comp onents of an optically created two-dimensional electron gas are well descri bed by Fermi-Dirac distributions with a common temperature but different ch emical potentials. In intrinsic wells, where excitonic effects dominate the optical properties, we show that exciton-exciton interaction produces a br eaking of the spin degeneracy in two-dimensional semiconductors, which can be tuned by the application of an external electric field. (C) 2001 Elsevie r Science B.V. All rights reserved.