Observations of electron-hole asymmetry in transport through graphene devices at high magnetic field challenge prevalent models of the graphene quantum Hall effect. Here, we study this asymmetry both in conventional magnetotransport and in scanning gate microscopy maps measured in an encapsulated graphene constriction. We reveal that the presence of upstream modes and local doping in the vicinity of electrical contacts leads to a totally different picture of topological breakdown for electrons and holes, explaining the observed asymmetry.
@article{arxiv.2103.10331,
title = {Contacts and upstream modes explain the electron-hole asymmetry in the graphene quantum Hall regime},
author = {Nicolas Moreau and Boris Brun and Sowmya Somanchi and Kenji Watanabe and Takashi Taniguchi and Christoph Stampfer and Benoît Hackens},
journal= {arXiv preprint arXiv:2103.10331},
year = {2021}
}