Interaction Effects and Viscous Magneto-Transport in a Strongly Correlated 2D Hole System

TL;DR

This study investigates magneto-transport in a strongly interacting 2D hole system, revealing a transition from negative to positive magneto-resistance with increasing temperature, attributed to viscous hydrodynamic effects.

Contribution

It demonstrates the emergence of positive magneto-resistance at high temperatures due to viscous hydrodynamic transport in a strongly correlated 2D hole system, a novel observation in this regime.

Findings

Negative parabolic magneto-resistance at low T consistent with FL theory

Positive magneto-resistance at high T attributed to viscous hydrodynamics

High interaction parameter $r_s$ indicating strong correlations

Abstract

Fermi liquid theory has been a foundation in understanding the electronic properties of materials. For weakly interacting two-dimensional (2D) electron or hole systems, electron-electron interactions are known to introduce quantum corrections to the Drude conductivity in the FL theory, giving rise to temperature dependent conductivity and magneto-resistance. Here we study the magneto-transport in a strongly interacting 2D hole system over a broad range of temperatures ($T$ = 0.09 to $>$1K) and densities $p=1.98-0.99\times10^{10}$ cm$^{-2}$ where the ratio between Coulomb energy and Fermi energy $r_s$ = 20 - 30. We show that while the system exhibits a negative parabolic magneto-resistance at low temperatures ($\lesssim$ 0.4K) characteristic of an interacting FL, the FL interaction corrections represent an insignificant fraction of the total conductivity. Surprisingly, a positive magneto-resistance emerges at high temperatures and grows with increasing temperature even in the regime $T \sim E_F$, close to the Fermi temperature. This unusual positive magneto-resistance at high temperatures is attributed to the collective viscous transport of 2D hole fluid in the hydrodynamic regime where holes scatter frequently with each other. These findings highlight the collective transport in a strongly interacting 2D system in the $r_s\gg 1$ regime and the hydrodynamic transport induced magneto-resistance opens up possibilities to new routes of magneto-resistance at high temperatures.