Hopping conductivity in the quantum Hall effect: revival of universal scaling.
We have measured the temperature dependence of the conductivity sigma(xx) of a two-dimensional electron system deep into the localized regime of the quantum Hall plateau transition. Using variable-range hopping theory we extract directly the localization length xi from this experiment. We use our results to study the scaling behavior of xi as a function of the filling factor distance /deltanu/ to the critical point of the transition. We find for all samples a power-law behavior xi equivalent to /deltanu/(-gamma) in agreement with the theoretically proposed universal exponent gamma = 2.35.
Hohls
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Institut für Festkörperphysik, Universität Hannover, Appelstrasse 2, 30167 Hannover, Germany. hohls@nano.uni-hannover.de
Zeitler
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Haug
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