There is a long standing interest to relate the optical properties of nanostructures to its atomistic configuration. Recently, we have shown that the magnetic field can be used to extract detailed information about the underlying structure [1,2]: The exciton energy increases with applied magnetic field (diamagnetic shift). We have shown that the diamagnetic shift scales with the localization length of the exciton wave function, and is therefore related to the disorder properties of the underlying potential. We have studied this problem using the full exciton solution (four coordinates) and a simpler factorization approach.

Fig. 1 The distribution of the diamagnetic shifts at B = 5 T calculated with the full solution (full symbols) and factorization (open symbols) for different strengths of disorder. (T=1.8K)

Aharonov-Bohm effect:

The Aharonov - Bohm effect is one of the most exciting fundamental effects connected with the magnetic field and special and has gained a lot of interest since its discovery in 1959. Originally studied for charged particles in a ring-like topology, we have predicted this effect to be observable even for (neutral) excitons [3,4]. Our calculations have shown that the exciton Aharonov - Bohm effect can only be observed if the exciton wave function connects around the origin, which requires small ring radii and a weak Coulomb attraction between electron and hole. To reach this goal we have proposed a new type of nanostructure, namely type II nanorings, where electron and hole are spatially separated.

Fig. 2 Projected hole density at B = 0 T. Electron position is fixed and indicated by black rectangle. The ring boundaries are shown as dashed circles.

Literature