We present nonlocal resistance measurements in an ultra high mobility two dimensional electron gas. Our experiments show that even at weak magnetic fields classical guiding along edges leads to a strong non local resistance on macroscopic distances.
In this high Landau level regime the transport along edges is dissipative and can be controlled by the amplitude of the voltage drop along the edge. We report resonances in the nonlocal transport as a function of this voltage that are interpreted as escape and formation of edge channels.
The magnetotransport properties of high mobility two dimensional electron gas have recently attracted a significant interest due to the discovery of microwave induced zero resistance states. Here we show experimentally that microwave irradiation with
a photon energy much smaller than the spacing between Landau levels can induce a strong decrease in the four terminal resistance. This effect is not predicted by the bulk transport models introduced to explain zero resistance states, but can be naturally explained by an edge transport model. This highlights the importance of edge channels for zero resistance state physics that was proposed recently.
