Magnetotransport along a barrier: Multiple quantum interference of edge states

Transport in a two-dimensional (2D) electron gas subject to an external magnetic field is analyzed in the presence of a longitudinal barrier. We show that quantum interference of the edge states bound by the longitudinal barrier results in a drastic change of the electron motion: the degenerate discrete Landau levels are transformed into an alternating sequence of energy bands and energy gaps. These features of the electron spectrum should result in a high sensitivity of thermodynamic and transport properties of the 2D electron gas to external fields. In particular, we predict giant oscillations of the ballistic conductance and discuss nonlinear current-voltage characteristics, coherent Bloch oscillations, and effects of impurities.