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 2×109 to View the MathML source. 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.