Two-dimensional hydrodynamic viscous electron flow in annular Corbino rings

TL;DR

This study demonstrates viscous hydrodynamic electron flow in high-mobility GaAs/AlGaAs 2DEGs using nonlocal transport measurements and Navier-Stokes simulations, highlighting the role of electron-electron interactions.

Contribution

First experimental evidence of viscous hydrodynamic electron flow in annular GaAs/AlGaAs 2DEGs supported by simulations and nonlocal measurements.

Findings

Viscous flow occurs far from source-drain regions.

Measurements agree with Navier-Stokes simulations below 1K.

Electron-electron interactions are crucial for hydrodynamic transport.

Abstract

The concept of fluidic viscosity is ubiquitous in our everyday life and for it to arise the fluidic medium must necessarily form a continuum where macroscopic properties can emerge. While a powerful concept for tangible liquids, hydrodynamic manifestation of collective flow in electronic systems such as two-dimensional electron gases (2DEGs) has only been shown recently to occur in graphene and GaAs/AlGaAs. Here, we present nonlocal electronic transport measurements in concentric annular rings formed in high-mobility GaAs/AlGaAs 2DEGs and the resulting data strongly suggest that viscous hydrodynamic flow can occur far away from the source-drain current region. Our conclusion of viscous electronic transport is further corroborated by simulations of the Navier-Stokes equations that are found to be in agreement with our measurements below 1K temperature. Most importantly, our work emphasizes the key role played by viscosity via electron-electron (e-e) interaction when hydrodynamic transport is restricted radially, and for which a priori should not have played a major role.