Intersublevel magnetoabsorption in the valence band of p-type InAs/GaAs and Ge/Si self-assembled quantum dots -: art. no. 125342

The linear intraband (intersublevel) optical magnetoabsorption between the valence-band states in thin disk-shaped self-assembled quantum dots is studied. Strain is modeled with the continuum mechanical approach, while band mixing and the magnetic field are taken into account through the axially symmetric k.p model. The absorption spectra in InAs/GaAs and Ge/Si quantum dots are computed for the case when a magnetic field perpendicular to the dot's base is present for both p-polarization in the Voigt configuration and s-polarization in the Faraday configuration. Due to the selection rules, the transitions between the states which differ by +/- 1 in the total angular momentum (F-z) dominate for s-polarized light, while the transitions between the states of different F, are strictly forbidden for p-polarization. In InAs/GaAs quantum dots, the magnetic field brings about a red shift of the absorption peak for s-polarized light, while the absorption peak for p-polarization is blue-shifted with respect to the zero field case, and also the absorption curves widen. In Ge/Si, much smaller shifts of the absorption curves due to the magnetic field are found and almost no widening occurs, which is attributed to the larger number of energy levels in Ge/Si dots. The obtained results compare favorably with the spectroscopic measurements at zero magnetic field, especially with regard to the relative energies of the absorption peaks for s- and p-polarized light.