We demonstrate an innovative quantum Hall circuit with variable geometry employing the moveable electrostatic potential induced by a biased atomic force microscope tip. We exploit this additional degree of freedom to identify the microscopic mechanisms that allow two co-propagating edge channels to equilibrate their charge imbalance. Experimental results are compared with tight-binding simulations based on a realistic model for the disorder potential. This work provides also an experimental realization of a beam mixer between co-propagating edge channels, a still elusive building block of a recently proposed new class of quantum interferometers.
@article{arxiv.1102.4170,
title = {Spatially-resolved analysis of edge-channel equilibration in quantum Hall circuits},
author = {Nicola Paradiso and Stefan Heun and Stefano Roddaro and Davide Venturelli and Fabio Taddei and Vittorio Giovannetti and Rosario Fazio and Giorgio Biasiol and Lucia Sorba and Fabio Beltram},
journal= {arXiv preprint arXiv:1102.4170},
year = {2012}
}