gfactor of electrons in an InAs quantum well

We have studied the spin splitting of Landau levels for a two-dimensional electron gas in an InAs/GaSb single quantum well. The effective g factor, $g^{\mathrm{*}}$, is between 7.8 and 8.7 which is below the bulk value. The reduction in $g^{\mathrm{*}}$ is due to nonparabolicity effects resulting from confinement of free electrons to a narrow quantum well. Under these circumstances $g^{\mathrm{*}}$ enhancement due to many-body effects is smaller than the reduction due to nonparabolicity.