OSCILLATORY TUNNELING BETWEEN QUANTUM HALL SYSTEMS

Electron tunneling between quantum Hall systems on the same two-dimens ional plane separated by a narrow barrier is studied. We show that in the limit where the inelastic scattering time is much longer than the tunneling time, which can be achieved in practice, electrons can tunne l back and forth through the barrier continuously, leading to an oscil lating current in the absence of external drives. The oscillatory beha vior is dictated by a tunneling gap in the energy spectrum. We shall d iscuss ways to generate oscillating currents and the phenomenon of nat ural dephasing between the tunneling currents of edge states. The nois e spectra of these junctions are also studied. They contain singularit ies reflecting the existence of tunneling gaps as well as the inherent oscillation in the system.