Effect of strain on the magnetoexciton ground state in $\mathrm{InP}/{\mathrm{Ga}}_x{\mathrm{In}}_{1-x}\mathrm{P}$ quantum disks

The ground-state properties of an exciton in a self-assembled quantum disk are calculated in the presence of a perpendicular magnetic field. For sufficient wide and thin dots, the strain field leads to a confinement of the heavy hole within the dot and the system is type I, while the light hole is confined outside the dot and the system is type II. However, with increasing disk thickness, the strain induces a transition of the heavy hole from inside the disk towards the radial boundary outside the disk. For the exciton, we predict a heavy-hole to light-hole transition as a function of the disk thickness, i.e., forming a “ringlike” hole wave function. There is a range of parameters (radius and height of the disk) for which a magnetic field can induce such a heavy-to-light hole transition. The diamagnetic shift was compared with results from magnetophotoluminescence experiments, where we found an appreciable discrepancy. The origin of this discrepancy was investigated by varying the disk parameters, the valence-band offset, and the effective masses.