Spin imaging of Poiseuille flow of viscous electronic fluid

TL;DR

This paper proposes a spin imaging method to detect and analyze viscous electron flows in conductors, demonstrating how spin density and Hanle curves reveal hydrodynamic behavior.

Contribution

It introduces a novel spin imaging technique to non-invasively identify viscous electron hydrodynamic flows in conductors.

Findings

Injected electron spin density is inhomogeneous in Poiseuille flow.

Hanle curves show phase shifts across the channel due to velocity variations.

Method can be used to evidence viscous electron fluids.

Abstract

Recent progress in fabricating high-quality conductors with small densities of defects has initiated the studies of the viscous electron fluid and has motivated the search for the evidences of the hydrodynamic regime of electron transport. In this work we come up with the spin imaging technique allowing us to attest to the emergence of electron hydrodynamic flows. Based on numerical calculations we demonstrate that the injected electron spin density is inhomogeneous across the channel when the viscous electron fluid forms the Poiseuille flow. We also argue that the Hanle curves at different positions across the channel acquire relative phase shifts resulting from the variation of the electron drift velocity in inhomogeneous hydrodynamic flows. The studied effects can be employed to evidence and study the viscous electron fluid non-invasively.