Diamagnetic shift and oscillator strength of two-dimensional excitons under a magnetic field in ${\mathrm{In}}_{0.53}$${\mathrm{Ga}}_{0.47}$As/InP quantum wells

We studied magneto-optical absorption spectra of the ground-state electron-heavy-hole exciton resonance in ${\mathrm{In}}_{0.53}$${\mathrm{Ga}}_{0.47}$As/InP quantum wells. As the magnetic field perpendicular to the quantum-well layers was increased, the exciton resonance showed diamagnetic shifts and its integrated intensity increased. Magneto-optical data were analyzed using effective-mass equations which include conduction- and valence-subband nonparabolic dispersion and the wave-vector-dependent transition-matrix element with the second-order k⋅p terms. We found that the exciton wave function for the relative in-plane motion shrinks in real space and expands in k space due to the in-plane parabolic confinement potential by the magnetic fields. This enhanced the integrated intensity and thus, the oscillator strength. We evaluated the exciton reduced effective mass, Luttinger-Kohn valence-band effective-mass parameters, conduction-band effective mass, and a momentum matrix element between s- and p-state band-edge basis functions.