Hydrodynamic effects in interacting Fermi electron jets

TL;DR

This paper explores how electron-electron interactions in a two-dimensional Fermi system lead to a quantum pumping effect, where an electron beam can attract carriers from an aperture, differing from classical fluid dynamics.

Contribution

It introduces a novel quantum pumping mechanism caused by hydrodynamic effects in Fermi systems, distinct from classical Bernoulli effects.

Findings

Electron beam induces a positive potential attracting carriers.

The effect results from specific electric potential distribution.

It differs qualitatively from classical Bernoulli pumping.

Abstract

We theoretically study hydrodynamic phenomena originating from electron-electron collisions in a two-dimensional Fermi system. We demonstrate that an electron beam sweeping past an aperture creates a pumping effect, attracting carriers from this aperture. This pumping effect originates from the specific electric potential distribution induced by the injected electrons. In the regions nearby the main stream of injected electrons, a positive potential is induced by the injected electrons. Thus, the normally repulsive Coulomb interaction leads to an attractive force in the Fermi system. This quantum pumping mechanism in a Fermi system differs qualitatively from the Bernoulli pumping effect in classical liquids. We also discuss possible experimental realizations.