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

We report quantum Hall experiments on the plateau-insulator transition in a low mobility In_0.53Ga_0.47As/InP heterostructure. The data for the longitudinal resistance ρ_xx follow an exponential law and we extract a critical exponent κ = 0.55 ± 0.05 which is slightly different from the established value κ = .0.42 ± 0.04 for the plateau transitions. Upon correction for inhomogeneity effects, which cause the critical conductance σ*_xx to depend marginally on temperature, our data indicate that the plateau-plateau and plateau-insulator transitions are in the same universality class.