Direct evidence of tunneling between edge states across a gate-induced potential barrier

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Abstract
We have studied tunneling in the plane of a two-dimensional electron gas across the imposed potential barrier beneath a very short gate. In quantizing magnetic fields the tunnel conductance shows sharp peaks as a function of applied bias, which vary nonmonotonically in position and amplitude as the field is increased, showing a clear switching behavior near integer filling factors. Our data show reasonable qualitative agreement with a theoretical single-particle model of tunneling between edge states and we propose that this is the origin of our peak structures.