Type-II InAs/GaAsSb/GaAs quantum dots as artificial quantum dot molecules

摘要

We have studied theoretically the type-II GaAsSb capped InAs quantum dots fortwo structures differing in the composition of the capping layer, being either(i) constant or (ii) with Sb accumulation above the apex of the dot. We havefound that the hole states are segmented and resemble the states in the quantumdot molecules. The two-hole states form singlet and triplet with the splittingenergy of 4{\mu}eV / 325{\mu}eV for the case (i) / (ii). We have also testedthe possibility to tune the splitting by vertically applied magnetic field. Asthe predicted tunability range was limited, we propose an approach for itsenhancement.