PROPERTIES OF THE APPARENT METAL-INSULATOR-TRANSITION IN 2-DIMENSIONAL SYSTEMS

The low-temperature conductivity of low-density, high-mobility, two-di mensional hole systems in GaAs was studied. We explicitly show that th e metal-insulator transition, observed in these systems, is characteri zed by a well-defined critical density, p(0)(c). We also observe that the low-temperature conductivity of these systems depends linearly on the hole density, over a wide density range. The high-density linear c onductivity extrapolates to zero at a density close to the critical de nsity. [S0163-1829(98)50536-X].