Spin susceptibility of a variable-density two-dimensional electron system

We determine the spin susceptibility in a variable-density two-dimensional electron system in GaAs/AlGaAs. Our measurements extend over a wide range of low densities from 2 x 10(9) to 4 x 10(10) cm(-2). Our data can be well described by an empirical equation which incorporates both the density dependence and the magnetic field dependence of the spin susceptibility. It can explain the anomalous g-factors reported recently in GaAs electron and hole systems. The extrapolated paramagnetic spin susceptibility increases with decreasing density as expected from theoretical calculations. (C) 2003 Elsevier B.V. All rights reserved.