  Quantum transport measurements are performed in gate-defined, high-quality,
two-dimensional hole and electron systems in an undoped InSb quantum well. For
both polarities, the carrier systems show tunable spin-orbit interaction as
extracted from weak anti-localization measurements. The effective mass of InSb
holes strongly increases with carrier density as determined from the
temperature dependence of Shubnikov-de Haas oscillations. Coincidence
measurements in a tilted magnetic field are performed to estimate the spin
susceptibility of the InSb two-dimensional hole system. The g-factor of the
two-dimensional hole system decreases rapidly with increasing carrier density.
