Quantum-beat spectroscopy of the Zeeman splitting of heavy- and light-hole excitons in GaAs/${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As quantum wells

Quantum-beat spectroscopy is used to determine the exciton Zeeman splitting and Landé factor in narrow (30 Å) and wide (120 Å) GaAs quantum wells. We find that while the heavy-hole splitting decreases with well width, the light hole exhibits an opposite trend. Measurements of higher magneto-excitons of the wide well show significant increase in the Zeeman splitting with respect to the lowest heavy-hole excition.