Frictional Drag Between Coupled 2D Hole Gases in GaAs/AlGaAs Heterostructures

TL;DR

This paper presents the first experimental measurements of frictional drag between coupled two-dimensional hole gases in GaAs/AlGaAs heterostructures, analyzing how various parameters influence phonon-mediated coupling.

Contribution

It introduces the first measurements of drag effects in coupled 2D-hole gases and distinguishes phonon from plasmon coupling mechanisms using tunable parameters.

Findings

Drag effect observed between coupled 2D-hole gases.

Phonon coupling identified as the dominant mechanism.

Fermi wavevector and velocity tuning differentiate coupling types.

Abstract

We report on the first measurements of the drag effect between coupled 2D-hole gases. We investigate the coupling by changing the carrier densities in the quantum wells, the widths of the barriers between the gases and the perpendicular magnetic field. From the data we are able to attribute the frictional drag to phonon coupling, because the non-parabolicity allows to tune the Fermi wavevector and the Fermi velocity separately and, thereby, to distinguish between phonon- and plasmon-dominated coupling.