Nonexponential relaxations in a two-dimensional electron system in silicon

The relaxations of conductivity have been studied in a strongly disordered two-dimensional (2D) electron system in Si after excitation far from equilibrium by a rapid change of carrier density n(s) at low temperatures T. The dramatic and precise dependence of the relaxations on n(s) and T strongly suggests (a) the transition to a glassy phase as T -> 0, and (b) the Coulomb interactions between 2D electrons play a dominant role in the observed out-of-equilibrium dynamics.