Bulk and shear viscosities in multicomponent 2D electron system

TL;DR

This study measures and analyzes bulk and shear viscosities in a multicomponent 2D electron system within GaAs triple wells, revealing significant differences and temperature-dependent behaviors in magnetotransport properties.

Contribution

It provides the first detailed experimental determination of both bulk and shear viscosities in a multicomponent 2D electron system, highlighting the dominance of bulk viscosity at high temperatures.

Findings

Bulk viscosity is significantly larger than shear viscosity.

Positive magnetoresistance at high temperatures linked to bulk viscosity.

Negative magnetoresistance at low temperatures linked to shear viscosity.

Abstract

We investigated magnetotransport in mesoscopic samples containing electrons from three different subbands in GaAs triple wells. At high temperatures, we observed positive magnetoresistance, which we attribute to the imbalance between different types of particles that are sensitive to bulk viscosities. At low temperatures, we found negative magnetoresistance, attributed to shear viscosity. By analyzing the magnetoresistance data, we were able to determine both viscosities. Remarkably, the electronic bulk viscosity was significantly larger than the shear viscosity. Studying multicomponent electron systems in the hydrodynamic regime presents an intriguing opportunity to further explore the physics in systems with high bulk viscosity.