Continuous phase shift in the forced interference of edge states in the quantum Hall regime

The edge states in the quantum Hall regime are forced to interfere on one side of an Aharonov–Bohm ring by a potential barrier. The net effect of the interference caused by the potential barrier is found to change the electronʹs phase by Δ in the final transmittance, and the phase shift Δ is continuous as the barrier potential is continuously changed. This result is in sharp contrast with the earlier study that Δ=2nπ, where n is an integer, regardless of the barrier potential.