Abstract
We have studied the zero magnetic field resistivity ρ of unique high-mobility two-dimensional electron systems in silicon. At very low electron density (but higher than some sample-dependent critical value ∼ ), conventional weak localization is overpowered by a sharp drop of ρ by an order of magnitude with decreasing temperature below ∼1–2 K. No further evidence for electron localization is seen down to at least 20 mK. For <, the sample is insulating. The resistance is empirically found to scale with temperature both below and above with a single parameter that approaches zero at = suggesting a metal-insulator phase transition.
- Received 18 April 1994
DOI:https://doi.org/10.1103/PhysRevB.50.8039
©1994 American Physical Society