Zeeman Splitting of Excitons in GaAs/AlGaAs Quantum Wells in the Faraday Geometry

The Zeeman splitting in the GaAs/AlGaAs heterostructure is investigated experimentally. Numerical analysis performed for the wavefunctions of exciton states, which takes into account the bands of heavy holes, light holes, and the band split by the spin–orbit interaction, is the quantitative agreement with experimental data both for an exciton with a heavy hole and for that with a light hole. It is shown that for explaining the experimental values of the Zeeman splitting in the quantum well under investigation, it is necessary to take into account both the Coulomb interaction and the contribution from the three bands in the valence band. The effect of screening of exciton states by a 2D gas of electrons with concentration n ≈ 10⁹ cm^–2 is described. Numerical calculations are performed for a large range of quantum well widths and aluminum concentrations in barriers; the chart of the dependence of the effective g factor on these parameters is plotted for magnetic field B = 5 T.