Phase coherence and tunneling between edge-states in multiple GaAs/Al_xGa_-x-x-xAs rings

In a GaAs/AlGaAs 4-coupled-ring sample, large Aharonov-Bohm (AB) oscillations were studied up to harmonic order n = 8 for magnetic fields 0 < B < 4.5T. The frequencies of all harmonics of the AB oscillations decrease as predicted by a simple model. The results also suggest an increase of the quantum mechanical phase coherence length (lφ) with increased B. © 1994 Plenum Publishing Corporation.