Field-induced Coulomb coupling in semiconductor macroatoms: Application to "single-electron" quantum devices

An original approach for the control of exciton–exciton Coulomb coupling in semiconductor macroatoms/molecules is proposed. We show that by applying properly tailored external fields, we can induce—or significantly reinforce—excitonic dipoles, which in turn allows one to control and magnify intra- as well as interdot few-exciton effects. Such a dipole–dipole interaction mechanism will be accounted for within a simple analytical model, which is found to be in good agreement with fully three-dimensional calculations. The proposed approach may play an important role for the design and realization of fully optical quantum gates as well as ultrafast optical switches.