Berlin 2024 – scientific programme
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O: Fachverband Oberflächenphysik
O 29: Poster: 2D Materials
O 29.33: Poster
Tuesday, March 19, 2024, 12:30–14:30, Poster A
Intermediate diffusive-ballistic electron conduction around mesoscopic defects in graphene layers — Toni Marković1, Wei Huang1, William S. Huxter2, Pietro Gambardella1, and •Sebastian Stepanow1 — 1Department of Materials, ETH Zurich — 2Department of Physics, ETH Zurich
Non-diffusive effects in charge transport become relevant as device sizes and features become comparable to the electronic mean free path. As a model system, we investigate the spatial transport around mesoscopic defects, which we refer to as pits, in graphene with scanning tunneling potentiometry. Diffusive and ballistic contributions to the transport dipole are investigated by simultaneously resolving the nanoscale topography of the pits and measuring the local electrochemical potential change in the surrounding area. We find evidence of transport in the intermediate regime between diffusive and ballistic limits, as the potential changes around pits are substantially underestimated by diffusive models. We also observe a dependence of the dipole magnitude on the shape of the pits. Our experiments and modelling are supported by lattice Boltzmann simulations, which highlights the importance of the ratio between the pit size and the mean free path in the intermediate transport regime.
Keywords: scanning tunneling potentiometry; graphene; ballistic transport; electrochemical potential