Magnetoexcitons in a narrow single GaAs-Ga0.5Al0.5As quantum well grown by molecular-beam epitaxy

We present a series of magnetoreflectance investigations performed at liquid-helium temperature and up to 55 kG in the Faraday configuration for a narrow single GaAs-${\mathrm{Ga}}_{0.5}$ ${\mathrm{Al}}_{0.5}$As quantum well (width around 79 Å). Both right-hand and left-hand circularly polarized magnetoexciton polaritons have been selected for the heavy-hole- and light-hole-related transitions. From the experimental data, taking into account the electron-hole exchange interaction, we could obtain the diamagnetic shifts of both the light-hole and the heavy-hole excitons. We measured an enhancement of the electron Landé factor ($g_c$=-6.8±0.2) and a weak influence of the two-dimensional confinement on the valence-band Luttinger parameter (κ=1.37±0.13).