Experiments on delocalization and universality in the integral Quantum Hall effect.

We report a new result on electronic transport in between two quantum Hall plateaus for an InGaAs/InP heterostructure. We find that both transport coefficients rho sub (xy) and rho sub (xx) show a characteristic power law dependence on T. Specifically, the maximum of drho sub (xy) /dB diverges like ~T sup (-k) in the range 0.1K~T~4.2K. For the three Landau levels N=0, 1 and 1 we obtain the same value for the exponent k=0.42+-0. 04. In addition, we define a half-width DELTAB for the magnetoresistance rho sub (xx). This width vanishes as DELTAB~T sup k with the same exponent k. 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.