Kinetic coefficients of two-dimensional electrons with strong Zeeman splitting

TL;DR

This paper develops hydrodynamic equations for a viscous two-component 2D electron system with strong Zeeman splitting, enabling better understanding of magnetotransport phenomena in ultra-pure nanostructures.

Contribution

It introduces a kinetic theory-based hydrodynamic model for two-component 2D electron fluids with Zeeman splitting, accounting for shear viscosity and inter-component friction.

Findings

Derived relaxation rates for distribution function harmonics.

Formulated hydrodynamic equations including shear viscosity and friction.

Applicable to magnetotransport measurements in nanostructures.

Abstract

In nanostructures with two-dimensional (2D) electrons and very low defect densities, a hydrodynamic transport regime has recently been realized. In this regime, 2D electrons form a viscous fluid due to frequent electron-electron collisions. Many unusual and mysterious magnetotransport and high-frequency effects have been observed in these systems. Their understanding is crucial for a general comprehending the formation of hydrodynamic transport. Two-component electronic systems, where there are two types of carriers with different concentrations and relaxation times, are of particularly interest. These systems can be realized by filling two lower subbands in a quantum well with electrons, or by filling one subband and applying a strong magnetic field in the well plane, leading to a Zeeman splitting of the subband. In this work, we construct the hydrodynamic equations for a viscous two-component electronic fluid for a Zeeman-type two-component 2D electronic system. By solving the kinetic equation, we calculate the relaxation rates of the first and second harmonics of the two-component distribution function. The resulting balance hydrodynamic equations take into account the effect of shear viscosity in each component and the effect of the friction between the two components. The lastleads to the alignment of the velocities of the two components of the fluid. The obtained equations can be used to explain magnetotransport measurements in ultra-pure nanostructures in an inclined magnetic field, where two-component electronic fluid is formed.