gFactor of the Two-Dimensional Interacting Electron Gas

The g factor of quasiparticle states near the Fermi energy in a two-dimensional electron gas with Coulomb interactions is calculated in a static approximation. It is argued that this quadiparticle g factor, different from the free-electron g=2. 0023, is the relevant quantity for spin splittings in experiments such as those on de Haas-van Alphen or magnetoconductivity oscillations, and, in particular, in experiments on electrons in silicon surface inversion layers. The g factor observed in conduction-electron spin resonance, on the other hand, should be the bulk value of 1. 99.