Many-Exciton Complexes in Self-Assembled Quantum Dots

The system of interacting electrons and holes confined in a lens-shaped InGaAs self-assembled dot is studied using exact diagonalization techniques. The single-particle energy spectrum of self-assembled dot is well approximated by that of a quasi-two-dimensional atom with parabolic lateral confinement. The electronic shell structure of self-assembled dot is responsible for a remarkable dependence of the absorption/emission spectrum on the number of excitons. This is explained in terms of hidden symmetries leading to a formation of coherent many-exciton states of weakly interacting excitons and bi-excitons.