Indication of the Ferromagnetic Instability in a Dilute Two-Dimensional Electron System

The magnetic field $B_c$, in which the electrons become fully spin polarized, is found to be proportional to the deviation of the electron density from the zero-field metal-insulator transition in a two-dimensional electron system in silicon. The tendency of $B_c$ to vanish at a finite electron density suggests a ferromagnetic instability in this strongly correlated electron system.