Weak Localization, Hole-Hole Interactions, and the “Metal”-Insulator Transition in Two Dimensions

Abstract

A detailed investigation of the metallic behavior in high-quality GaAs-AlGaAs two-dimensional hole systems reveals the presence of quantum corrections to the resistivity at low temperatures. Despite the low density ( $r_s>10\mathrm{}$) and high quality of these systems, both weak localization (observed via negative magnetoresistance) and weak hole-hole interactions (giving a correction to the Hall constant) are present in the so-called metallic phase where the resistivity decreases with decreasing temperature. If these quantum corrections persist down to $T=0\mathrm{}$, the results suggest that even at high $r_s$ there is no metallic phase in two dimensions.