Tailoring exciton-exciton Coulomb coupling in semiconductor macroatoms using an external electric field

We present a novel approach for the control of exciton–exciton Coulomb coupling in semiconductor macroatoms/molecules. We exploit electron–hole charge separations induced by the presence of a static external electric field: in this way excitonic dipoles are significantly reinforced. This, in turn, allows us to control and magnify intra- as well as interdot few-exciton effects connected to dipole–dipole coupling. This 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 allows to control and tune exciton–exciton Coulomb coupling, a key quantity for the design and realization of novel single-electron/exciton devices.