Conductance fluctuations at the quantum Hall plateau transition

We analyze the conductance fluctuations observed in the quantum Hall regime for a bulk two-dimensional electron system in a Corbino geometry. We find that characteristics like the power spectral density and the temperature dependence agree well with simple expectations for universal conductance fluctuations in metals, while the observed amplitude is reduced. In addition, the dephasing length $L_{\Phi }\propto T^{-1/2},$ which governs the temperature dependence of the fluctuations, is surprisingly different from the scaling length $L_{\mathrm{sc}}\propto T^{-1}$ governing the width of the quantum Hall plateau transition.