EXCITON, HEAVY-HOLE, AND ELECTRON G-FACTORS IN TYPE-I GAAS/ALXGA1-XAS QUANTUM-WELLS

The magnetic g factor for n = 1 heavy-hole-electron excitons in type-I GaAs/AlxGa1-xAs quantum wells has been determined at 1.8 K as a function of well width (L(z)) from the Zeeman splitting of the luminescence line below 2 T. Combined with previously published g-factor measurements for electrons and heavy holes this gives a complete picture of the variation of the magnitudes and signs of the three g factors. The variation of electron g factor can be understood in terms of the nonparabolicity of the conduction band of GaAs using three-band k.p perturbation theory, but that of the hole and exciton g factors is not reproduced by existing theory, implying a well width dependence of the Luttinger parameters kappa and q.