Metal-insulator transition at B=0 in a dilute two dimensional GaAs-AlGaAs hole gas

Abstract

We report the observation of a metal insulator transition at B=0 in a high mobility two dimensional hole gas in a GaAs-AlGaAs heterostructure. A clear critical point separates the insulating phase from the metallic phase, demonstrating the existence of a well defined minimum metallic conductivity sigma(min)=2e/h. The sigma(T) data either side of the transition can be `scaled' on to one curve with a single parameter (To). The application of a parallel magnetic field increases sigma(min) and broadens the transition. We argue that strong electron-electron interactions (rs = 10) destroy phase coherence, removing quantum intereference corrections to the conductivity.

4 pages RevTex + 4 figures. Submitted to PRL. Originally posted 22 September 1997. Revised 12 October 1997 - minor changes to referencing, figure cations and figures