THE QUANTUM HALL-EFFECT IN FINITE STRUCTURES

Using the Landauer approach to electronic transport, we investigate nu merically conductance and Hall conductance of a disordered and dissipa tive finite quantum wire. Ohmic voltage and current contacts are imple mented by regions with gradually increasing dephasing rates. In this w ay, a self-stabilizing current distribution and well-defined Hall cond uctance plateaus are obtained, the accuracy of the latter depending on the spatial extension of the dephasing contact regions. We obtain the surprising result, that dephasing may improve conductance quantizatio n by suppressing interference effects. (C) 1998 Academic Press Limited .