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

TL;DR

This study investigates the quantum critical behavior of the plateau-insulator transition in a low-mobility InGaAs/GaAs quantum well, revealing critical exponents consistent with non-Fermi liquid behavior and confirming quantized Hall resistance during the transition.

Contribution

The paper provides new experimental measurements of critical exponents in the plateau-insulator transition, supporting the non-Fermi liquid nature of the quantum critical point.

Findings

Critical exponents kappa = 0.54 and 0.58 consistent with previous results.

Hall resistance remains quantized at h/e^2 during the transition.

Deviations from quantization reveal corrections to scaling.

Abstract

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.