Vorticity induced negative nonlocal resistance in viscous two-dimensional electron system

TL;DR

This paper demonstrates negative nonlocal resistance in a 2D electron gas due to viscous flow and whirlpool formation, highlighting hydrodynamic effects in mesoscopic electronic systems.

Contribution

It provides experimental evidence of viscous electron flow and whirlpool formation in a 2D electron system, supported by theoretical comparison.

Findings

Negative nonlocal resistance observed

Whirlpool formation confirmed as cause

Hydrodynamic regime dominates electron transport

Abstract

We report non-local electrical measurements in a mesoscopic size two-dimensional (2D) electron gas in a GaAs quantum well in a hydrodynamic regime. Viscous electric flow is expected to be dominant when electron-electron collisions occur more often than the impurity or phonon scattering events. We observe a negative nonlocal resistance and attribute it to the formation of whirlpools in the electron flow. We use the different nonlocal transport geometries and compare the results with a theory demonstrating the significance of hydrodynamics in mesoscopic samples.