Frictional drag between spatially separated two-dimensional electron gases mediated by virtual phonon exchange

TL;DR

This paper calculates the frictional drag between two spatially separated 2D electron gases mediated by virtual phonon exchange, highlighting the dominance of piezoelectric coupling and a temperature-dependent peak in drag scattering.

Contribution

It introduces a detailed theoretical calculation of phonon-mediated frictional drag, emphasizing the role of piezoelectric interaction and temperature effects in quantum wells.

Findings

Drag is dominated by piezoelectric coupling.

A peak in drag scattering rate occurs at about 2.1 K.

The peak is due to a transition from small to large angle scattering.

Abstract

We have calculated the frictional drag between spatially separated quantum wells with parallel two-dimensional electron gases due to interlayer electron-electron interaction mediated by virtual exchange of acoustic phonons due to piezoelectric and deformation potential interaction. It is shown that the frictional drag is dominated by the piezoelectric coupling. According to our calculations temperature dependence of the drag scattering rate divided by squared temperature T exhibits a pronounced peak which for the experimental situation and in agreement with the finding of T. J. Gramila, et al., Phys. Rev. B 47, (1993) 12957 is obtained at about T=2.1 K. We ascribe the appearance of this peak to a change from small to large angle scattering in the virtual phonon exchange.