Viscous magnetotransport and Gurzhi effect in bilayer electron system

TL;DR

This study demonstrates the Gurzhi effect and large negative magnetoresistance in a bilayer GaAs quantum well, showing enhanced hydrodynamic behavior and shorter slip length compared to single-layer systems.

Contribution

It provides experimental evidence and a hydrodynamic model describing electron transport in bilayer systems, highlighting differences from single-layer wells.

Findings

Bilayer system exhibits stronger electron-electron scattering than single well.

Slip length in bilayer is shorter, indicating deeper hydrodynamic regime.

Hydrodynamic model successfully explains magnetoresistance and resistivity behavior.

Abstract

We observe a large negative magnetoresistance and a decrease of resistivity with increasing temperature, known as the Gurzhi effect, in a bilayer electron (BL) system formed by a wide GaAs quantum well. A hydrodynamic model for the single fluid transport parameters in narrow channels is employed and successfully describes our experimental findings. We find that the electron-electron scattering in the bilayer is more intensive in comparison with a single-band well (SW). The hydrodynamic assumption implies a strong dependence on boundary conditions, which can be characterized by slip length, describing the behavior of a liquid near the edge. Our results reveal that slip length in a BL is shorter than in a SW, and that the BL system goes deeper into the hydrodynamic regime. This is in agreement with the model proposed where the slip length is of the order of the electron-electron mean free path.