Spin susceptibility and effective mass of a 2D electron system in GaAs heterostructures towards the weak interacting regime

We determined the spin susceptibility chi and the effective mass m{*} towards the high density limit. Using a tunable GaAs/AlGaAs heterostructure, we can vary the 2D electron density from n = 1 x 10(10) cm(-2) to 4 x 10(11) cm(-2). From similar to 5 x 10(10) cm(-2) to our highest densities the mass values fall similar to 10% below the band mass of GaAs. The enhancement of chi decreases monotonically from a factor of 3 to 0.88 with increasing density. It continues to follow a previously observed power law, which leads to an unphysical limit for n -> infinity. Band structure effects affecting mass and g-factor become appreciable for large n and, when taken into account, lead to the correct limiting behavior of chi. Numerical calculations are in qualitative agreement with our data but differ in detail. (c) 2006 Elsevier B.V. All rights reserved.