HALL RESISTANCE OF A 2-DIMENSIONAL ELECTRON-GAS IN THE PRESENCE OF MAGNETIC-FLUX TUBES

We compute the Hall and diagonal resistivities of a two-dimensional el ectron gas in the presence of randomly placed magnetic-flux tubes. It is found that there is a suppression of the Hall conductance below its expected value for the corresponding uniform magnetic-field case at l ow electron densities, in agreement with recent experiments. At densit ies somewhat lower than achieved thus far experimentally, we find reso nances in the transport coefficients due to Landau-level structure in the flux tubes. A classical calculation of the Hall resistance reprodu ces the broad features of the Hall conductance for integral or half-in tegral numbers of flux quanta in each flux tube.