While ballistic electrons are a key tool for applications in sensing and flying qubits, sub-nanosecond propagation times and complicated interactions make control of ballistic single electrons challenging. Recent experiments have revealed Coulomb collisions of counterpropagating electrons in a beam splitter, giving time resolved control of interactions between single electrons. Here we use remote Coulomb interactions to demonstrate a scheme for sensing single ballistic electrons. We show that interactions are highly controllable via electron energy and emission timing. We use a weakly-coupled `sensing' regime to characterise the nanoscale potential landscape of the beam splitter and the strength of the Coulomb interaction, and show multi-electron sensing with picosecond resolution.
@article{arxiv.2412.15789,
title = {Coulomb sensing of single ballistic electrons},
author = {J. D. Fletcher and W. Park and P. See and J. P. Griffiths and G. A. C. Jones and I. Farrer and D. A. Ritchie and H. -S. Sim and M. Kataoka},
journal= {arXiv preprint arXiv:2412.15789},
year = {2024}
}