Signatures of lateral coupling of double quantum dots in the exciton photoluminescence spectrum

We study an electron-hole pair in laterally coupled self-assembled quantum dots with an electric field applied in the plane of confinement. The interparticle correlations and the carrier distribution are calculated using a configuration interaction approach for dots with circular and square symmetry. We extract universal features of the photoluminescence spectra specific to the lateral coupling configuration and point out the differences with vertically coupled dots. These specific features include additional avoided crossings of the lowest bright exciton level as function of the external field. In the case of strong coupling, the avoided crossing related to exciton dissociation is anomalous and involves an interaction of three or four energy levels. The latter is a consequence of the hole state mixing appearing at the electron transfer between the dots.