Experiments on Delocalization and University in the Integral Quantum Hall Effect

We find that the transport coefficients ${\rho }_{\mathrm{xy}}$ and ${\rho }_{\mathrm{xx}}$ of two-dimensional electrons in InGaAs/InP show a characteristic power-law dependence on $T$. In the range $0.1 \mathrm{K} \lesssim T\lesssim 4.2 \mathrm{K}$, the maximum of $\frac{d{\rho }_{\mathrm{xy}}}{\mathrm{dB}}$ diverges like $\sim T^{-\kappa }$ with $\kappa =0.42\mathrm{}\pm 0.04$, for Landau levels $N=0\mathrm{}\downarrow$, $1\uparrow$, and $1\downarrow$, and the half-width $\Delta B$ for ${\rho }_{\mathrm{xx}}$ vanishes as $\Delta B\sim T^{\kappa }$. 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.