Doesm*g*Diverge at a Finite Electron Density in Silicon Inversion Layers?

For the two-dimensional electron system in silicon MOSFET's, the scaledmagnetoconductivity has been shown to exhibit critical behavior at finitedensity $n_0$. Analysis of these magnetotransport experiments yields a product$g^*m^*$ that diverges at this density (here $g^*$ is the interaction-enhancedLand\'e $g$-factor and $m^*$ is the effective mass). This claim has beendisputed based on direct determinations of the $g^*m^*$ obtained fromShubnikov-de Haas measurements. We briefly review these experiments, andpossible sources of the discrepancies.