New Insights into the Plateau-Insulator Transition in the Quantum Hall Regime

L. A. Ponomarenko, D. T. N. de Lang, A. de Visser, D. Maude, B. N. Zvonkov, R. A. Lunin, A. M. M. Pruisken

Published 2003-08-19Version 1

We have measured the quantum critical behavior of the plateau-insulator (PI) transition in a low-mobility InGaAs/GaAs quantum well. The longitudinal resistivity measured for two different values of the electron density follows an exponential law, from which we extract critical exponents kappa = 0.54 and 0.58, in good agreement with the value (kappa = 0.57) previously obtained for an InGaAs/InP heterostructure. This provides evidence for a non-Fermi liquid critical exponent. By reversing the direction of the magnetic field we find that the averaged Hall resistance remains quantized at the plateau value h/e^2 through the PI transition. From the deviations of the Hall resistance from the quantized value, we obtain the corrections to scaling.