Electrical tuning of exciton g factors in quantum dot molecules: Effect of hole localization

We present a theoretical study of electron and hole g factors in stacked self-assembled InAs/GaAs quantum dots. The exciton ground and first excited states in the quantum dot molecules are found to exhibit opposite resonances in their g factors in the presence of a small vertical electric field, which is very different from the monotonic behavior of their counterparts in single quantum dots. While the g factor of the electronic ground state is seen to have little variation as the applied electric field increases, the relocalization of the hole states in coupled quantum dots is found to account for the resonant behavior of the exciton g factors. Our theoretical result agrees well with a recent experiment. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3227653]