Phase sensitivity and thermal dephasing in coherent electron transport in quasi one-dimensional (1D) waveguide rings of an asymmetric four-terminal geometry are studied by magnetotransport measurements. We demonstrate the electrostatic control of the phase in Aharonov-Bohm (AB) resistance oscillations and investigate the impact of the measurement circuitry on decoherence. Phase rigidity is broken due to the ring geometry: Orthogonal waveguide cross-junctions and 1D leads minimize reflections and resonances between leads allowing for a continuous electron transmission phase shift. The measurement circuitry influences dephasing: Thermal averaging dominates in the non-local measurement configuration while additional influence of potential fluctuations becomes relevant in the local configuration.
@article{arxiv.1005.2081,
title = {Control of the transmission phase in an asymmetric four-terminal Aharonov-Bohm interferometer},
author = {Sven S. Buchholz and Saskia F. Fischer and Ulrich Kunze and Matthew Bell and Dirk Reuter and Andreas D. Wieck},
journal= {arXiv preprint arXiv:1005.2081},
year = {2011}
}