Interedge phase coherence in quantum Hall line junctions

Abstract

Kang et al. have recently observed a remarkable zero-bias anomaly in the spectrum for electron tunneling between two two-dimensional electron gases separated laterally by a narrow but high barrier in the presence of a perpendicular quantizing magnetic field. We argue that this is a result of interedge phase coherence analogous to the interlayer phase coherence seen in quantum Hall effect (QHE) bilayer systems. The disruption of the QHE by the barrier is ``healed'' by strong Coulomb exchange enhancement of the weak tunneling through the barrier.