title: High frequency conductivity in the quantum hall regime.
abstract: We have measured the complex conductivity sigma(xx) of a two-dimensional electron system in the quantum Hall regime up to frequencies of 6 GHz at electron temperatures below 100 mK. Using both its imaginary and real part we show that sigma(xx) can be scaled to a single function for different frequencies and several transitions between plateaus in the quantum Hall effect. Additionally, the conductivity in the variable-range hopping regime is used for a direct evaluation of the localization length xi. Even for large filling factor distances deltanu from the critical point we find xi approximately equals deltanu(-gamma) with a scaling exponent gamma = 2.3.
authors.affiliation: Institut für Festkörperphysik, Universität Hannover, Applestrasse 2, 30167 Hannover, Germany. hohls@nano.uni-hannover.de
authors.forename: F
authors.initials: F
authors.lastname: Hohls
authors.forename: U
authors.initials: U
authors.lastname: Zeitler
authors.forename: R J
authors.initials: RJ
authors.lastname: Haug