Manipulation of the excitonic properties of GaAs quantum dots via strain fields

Epitaxial semiconductor quantum dots like InAs/GaAs or GaAs/AlGaAs are excellent quantum emitters and because of their field-tunable properties they can provide key components of quantum information devices, such as quantum repeaters. A solid understanding of the effect of applied external fields on the exciton states is crucial for the optimized operation of devices. Based on atomistic million-atom empirical pseudopotential calculations we show the effect of biaxial and uniaxial external strain fields on the exciton levels and relate them to the change of the hole states. It turns out, that uniaxial strain can change the natural hole quantization axis, while biaxial strain leads to an interesting heavy-hole light-hole transition. This transition comes along with a non-trivial spin-mixing and optical polarization anisotropies. Both effects may be useful for new technical devices in quantum information networks.