Glass transition in a two-dimensional electron system in silicon

Large fluctuations of conductivity with time are observed in a low-mobility two-dimensional electron system in silicon at low electron densities ns and temperatures. A dramatic increase of the noise power (∝1/fα) as ns is reduced below a certain density ng, and a sharp jump of α at ns≈ng, are attributed to the freezing of the electron glass at ns=ng. The data strongly suggest that glassy dynamics persists in the metallic phase.