Spin susceptibility of a two-dimensional electron system in GaAs towards the weak interaction region

We determine the spin susceptibility chi in the weak interaction regime of a tunable, high quality, two-dimensional electron system in a GaAs/AlGaAs heterostructure. The band structure effects, modifying mass and g-factor, are carefully taken into accounts since they become appreciable for the large electron densities of the weak interaction regime. When properly normalized, chi decreases monotonically from 3 to 1.1 with increasing density over our experimental range from 0.1 to 4x10(11) cm(-2). In the high density limit, chi tends correctly towards chi -> 1 and compare well with recent theory.