Disorder-tuned transition between a quantum Hall liquid and Hall insulator

Abstract

We report measurements of the disorder-driven phase transition from a quantum Hall liquid to Hall insulator at \ensuremath{\nu}=1/3 and \ensuremath{\nu}=2 observed in a two-dimensional electron gas. The data show good scaling behavior over a wide range of densities and temperatures with an exponent 1/zx\ensuremath{\sim}0.43 for both \ensuremath{\nu}=1/3 and 2, where z is the dynamical exponent and x is the correlation length exponent. The critical conductance at the transition is found to be ${\mathrm{\ensuremath{\sigma}}}_{\mathit{xx}}$=0.09\ifmmode\pm\else\textpm\fi{}0.01${\mathit{e}}^{2}$/h for the \ensuremath{\nu}=1/3 transition and ${\mathrm{\ensuremath{\sigma}}}_{\mathit{xx}}$=0.9\ifmmode\pm\else\textpm\fi{}0.15${\mathit{e}}^{2}$/h for the \ensuremath{\nu}=2 case.