Experiments on Delocalization and University in the Integral Quantum Hall Effect

We find that the transport coefficients ρxy and ρₓₓ of two-dimensional electrons in InGaAs/InP show a characteristic power-law dependence on T. In the range 0.1 K T 4.2 K, the maximum of dρxydB diverges like ~T^-κ with κ=0.42±0.04, for Landau levels N=0↓, 1↑, and 1↓, and the half-width ΔB for ρₓₓ vanishes as ΔB~T^κ. These results confirm the prediction of the scaling theory that the characteristic power-law behavior in the transport coefficients is a universal feature of delocalization in the integral quantum Hall effect.