Observation of the nu =1 quantum Hall effect in a strongly localized two-dimensional system.

Abstract

We observe a magnetic-field-driven transition in the two-dimensional electron system in GaAs/${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$As, from a strongly localized insulating phase at B=0 to the integer quantum Hall phase that includes a fully developed \ensuremath{\nu}=1 state. The quantum Hall phase terminates with an additional transition from the \ensuremath{\nu}=1 state to an insulating phase.