With an atomic force microscope a ring geometry with self-aligned in-plane gates was directly written into a GaAs/AlGaAs-heterostructure. Transport measurements in the open regime show only one transmitting mode and Aharonov-Bohm oscillations with more than 50% modulation are observed in the conductance. The tuning via in-plane gates allows to study the Aharonov-Bohm effect in the whole range from the open ring to the Coulomb-blockade regime.
@article{arxiv.cond-mat/0202403,
title = {Aharonov-Bohm oscillations of a tunable quantum ring},
author = {U. F. Keyser and S. Borck and R. J. Haug and W. Wegscheider and M. Bichler and G. Abstreiter},
journal= {arXiv preprint arXiv:cond-mat/0202403},
year = {2009}
}