CONDUCTANCE FLUCTUATIONS IN 2-DIMENSIONAL SYSTEMS IN RANDOM MAGNETIC-FIELDS

The conductance of a two-dimensional system subject to a random magnetic field is calculated within the Landauer-Buttiker formalism. Although there is no potential disorder the random fluctuating magnetic field introduces a random vector potential. Electrons in bulk states are found to be strongly scattered by the fluctuating field. In contrast, edge states are found to be quite stable even if the fluctuation of the field is of the order of a uniform background field. In a fully random field, the U(1) model, clear universal conductance fluctuations (UCF) are observed. The magnitude of the fluctuations is compared with that in the time reversal symmetric Z2 model.