Regensburg 2022 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 7: Fluctuations, Noise, Magnetotransport, and Related Topics
TT 7.6: Vortrag
Montag, 5. September 2022, 16:30–16:45, H23
Direct observation of vortices in an electron fluid — •Tobias Völkl1, Amit Aharon-Steinberg1, Arkady Kaplan1, Arnab Pariari1, Indranil Roy1, Tobias Holder1, Yotam Wolf1, Alexander Meltzer1, Yuri Myasoedov1, Martin Huber2, Binghai Yan1, Gregory Falkovich3, Leonid Levitov4, Markus Hücker1, and Eli Zeldov1 — 1Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel — 2Departments of Physics and Electrical Engineering, University of Colorado Denver, Denver, USA — 3Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot, Israel — 4Department of Physics, Massachusetts Institute of Technology, Cambridge, USA
Strongly-interacting electrons in ultrapure conductors have been shown to display signatures of hydrodynamic behavior including negative nonlocal resistance and Poiseuille flow in narrow channels. Here we provide the first visualization of current vortices in an electron fluid. By utilizing a nanoscale scanning superconducting quantum interference device on a tip we image the current distribution in a circular chamber connected through a small aperture to a current-carrying strip in the high-purity type-II Weyl semimetal WTe2. We find that vortices are present only for small apertures, whereas the flow is laminar (non-vortical) for larger apertures. Our findings suggest a novel mechanism of hydrodynamic flow in thin pure crystals: the spatial diffusion of electrons’ momenta is enabled by small-angle scattering at the surfaces, instead of the routinely invoked electron-electron scattering.