Evidence for a quantum Hall insulator in an InGaAs/InP heterostructure

We study the quantum critical behavior of the plateau–insulator (PI) transition in a low mobility In0.53Ga0.47As/InP heterostructure. By reversing the direction of the magnetic field (B) we find an averaged Hall resistance ρxy which remains quantized at the plateau value h/e2 throughout the PI transition. We extract a critical exponent κ′=0.57±0.02 for the PI transition which is slightly different from the established value 0.42±0.04 as previously obtained from the plateau–plateau transitions.