Universal scaling results for the plateau-insulator transition in the quantum Hall regime

The plateau-insulator (PI) transition in the quantum Hall regime, in remarkable contrast to the plateau-plateau (PP) transition, exhibits very special features that enable one for the first time to disentwine the quantum critical aspects of the electron gas (scaling functions, critical indices) from the sample dependent effects of macroscopic inhomogeneities (contact misalignments, density gradients). In this communication we report new experimental data taken from the PI transition of a low-mobility InGaAs/InP heterostructure and propose universal scaling functions for the transport coefficients. Our new findings elucidate fundamental theoretical aspects of quantum criticality that have so far remained inaccessible. (c) 2006 Elsevier Ltd. All rights reserved.