Aharonov-Bohm effect of quantum Hall edge channels

We fabricated quantum rings by means of local anodic oxidation with an atomic force microscope on GaAs/AlGaAs-heterostructures. In low magnetic fields we observe the Aharonov-Bohm effect of I D channels in the ring with a period of 60-80 mT, for different devices. By careful tuning the in-plane gate voltages of the ring we also observe Aharonov-Bohm type of oscillations in the quantum Hall regime, with a surprisingly large period when compared to the low field Aharonov-Bohm oscillations. (c) 2007 Elsevier B.V. All rights reserved.