Two quantum dots with tunable mutual tunnel coupling have been embedded in a two-terminal Aharonov-Bohm geometry. Aharonov-Bohm oscillations are investigated in the cotunneling regime. Visibilities of more than 0.8 are measured indicating that phase-coherent processes are involved in the elastic and inelastic cotunneling. An oscillation-phase change of pi is detected as a function of bias voltage at the inelastic cotunneling onset.
@article{arxiv.cond-mat/0508757,
title = {Phase coherence in the inelastic cotunneling regime},
author = {M. Sigrist and T. Ihn and K. Ensslin and D. Loss and M. Reinwald and W. Wegscheider},
journal= {arXiv preprint arXiv:cond-mat/0508757},
year = {2009}
}