Probing the plateau-insulator quantum phase transition in the quantum Hall regime

TL;DR

This study investigates the quantum Hall plateau-insulator transition in a low mobility heterostructure, revealing a critical exponent slightly different from previous values and suggesting a shared universality class for different transitions.

Contribution

It provides new experimental data on the critical behavior of the plateau-insulator transition, including a refined critical exponent and insights into universality classes.

Findings

Critical exponent =0.55 b1 0.05 for the transition

Plateau-insulator and plateau-plateau transitions share the same universality class

Inhomogeneity effects influence the temperature dependence of critical conductance

Abstract

We report quantum Hall experiments on the plateau-insulator transition in a low mobility In_{.53} Ga_{.47} As/InP heterostructure. The data for the longitudinal resistance \rho_{xx} follow an exponential law and we extract a critical exponent \kappa= .55 \pm .05 which is slightly different from the established value \kappa = .42 \pm .04 for the plateau transitions. Upon correction for inhomogeneity effects, which cause the critical conductance \sigma_{xx}^* to depend marginally on temperature, our data indicate that the plateau-plateau and plateau- insulator transitions are in the same universality class.