Temperature dependence of the conductivity and minimum quantum mobility of a highly disordered dilute two-dimensional electron gas

We report the first experimental observations of magnetic-field-independent corrections to the conductivity of a weakly interacting 2D electron gas on solid on H₂. These incoherent corrections, which are substantially larger than the weak-localization terms at high helium-gas densities, are estimated via an electron-trapping model. The model has essentially no adjustable parameters and gives a self-consistent extrapolation between the weak- and strong-disorder limits. In the regime in which trapping is dominant we observe a residual electron mobility μᵣₑₛ{~}T^-1 associated with a lower quantum limit of diffusion.