Abstract
We determine the effective g-factor (|g^∗|) of a two-dimensional electron gas (2DEG) using a new method based on capacitance spectroscopy. The capacitance-voltage profile of a 2DEG in an InAs/AlGaSb quantum well measured in an in-plane magnetic field shows a double-step feature that indicates the Zeeman splitting of the subband edge. The method allows for simultaneous and independent determination of |g^∗| and effective mass m^∗. Data suggest that the biaxial tensile strain in the InAs layer has considerable impacts on both m^∗ and g^∗. Our method provides a means to determine |g^∗| that is complementary to the commonly used coincidence technique.