Effects of interchannel coupling in a two-dimensional electron gas at high magnetic fields

Using a top gate covering one-third of a Hall bar on a GaAs/AlₓGa_1-xAs heterojunction, the effect of the coupling between the innermost bulk channel and the outermost edge channels on the electron transport in the dissipative regime is studied. The longitudinal resistance is found to oscillate on the gated side as the gate voltage diminishes, while on the ungated side a large decrease in the longitudinal resistance is observed when the innermost bulk channel is pressed out from the gated region alone. We analyze the results in terms of the Landauer-B\"uttiker picture and show that in the dissipative regime the innermost bulk channel is important only to facilitate backscattering, but not for the current transport.