Metallic behavior in dilute two-dimensional hole systems

We have studied the metallic behavior in low-density two-dimensional p-GaAs systems, close to the apparent metal-insulator transition. Two observations are made concerning the origins of the metallic-like behavior. Within a given sample the strength of the metallic behavior is almost independent of the asymmetry of the confining potential, and is predominantly determined by the low-temperature resistivity (i.e., by k(F)l). In all our samples we find that at low densities, close to the transition from insulating to metallic behavior, the fractional decrease in conductivity with increasing temperature scales as T/T-F.