Apparent Metallic Behavior at B = 0 of a two-dimensional electron system in AlAs

TL;DR

This paper reports the observation of metallic-like behavior at zero magnetic field in a 2D electron system in AlAs, showing a transition from metallic to insulating behavior as electron density decreases, indicating a potentially universal phenomenon.

Contribution

It demonstrates metallic behavior at B=0 in AlAs 2D electrons and explores the density-dependent transition, extending understanding of 2D electron systems.

Findings

Metallic-like behavior observed at low temperatures and zero magnetic field

Resistance decreases with temperature at high densities

Transition to insulating behavior at lower densities

Abstract

We report the observation of metallic-like behavior at low temperatures and zero magnetic field in two dimensional (2D) electrons in an AlAs quantum well. At high densities the resistance of the sample decreases with decreasing temperature, but as the density is reduced the behavior changes to insulating, with the resistance increasing as the temperature is decreased. The effect is similar to that observed in 2D electrons in Si-MOSFETs, and in 2D holes in SiGe and GaAs, and points to the generality of this phenomenon.