Exciton interaction and spin dynamics in semiconductor heterostructures

A consistent theory of exciton interaction which affects the coherent excit on spin dynamics and its dephasing is constructed. For the low-density exci ton regime, the nonlinear equation for the exciton polarization adds to the Gross-Pitaevskii equation spin-dependent correlation terms, permitting an examination of the correlation effects on the optically excited spin dynami cs. We apply the theory to investigate the collective spin oscillations und er optical excitation. (C) 2000 Elsevier Science B.V. All rights reserved.