Novel Properties of The Apparent Metal-Insulator Transition in Two-Dimensional Systems

TL;DR

This paper investigates the metal-insulator transition in two-dimensional GaAs hole systems, revealing a well-defined critical density and a linear dependence of conductivity on hole density, with implications for understanding electronic phase transitions.

Contribution

It provides new experimental evidence of a well-defined critical density and linear conductivity behavior near the metal-insulator transition in 2D systems.

Findings

Identification of a well-defined critical density p_0c.

Linear dependence of conductivity on hole density.

Extrapolation of high-density conductivity to zero near p_0c.

Abstract

The low-temperature conductivity of low-density, high-mobility, two-dimensional hole systems in GaAs was studied. We explicitly show that the metal-insulator transition, observed in these systems, is characterized by a well-defined critical density, p_0c. 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 conductivity extrapolates to zero at a density close to the critical density.