Evidence for 2k_F Electron-Electron Scattering Processes in Coulomb Drag

TL;DR

This paper presents experimental and theoretical evidence that 2k_F electron-electron scattering processes significantly influence Coulomb drag in low-density, closely spaced 2D electron systems, especially at small layer separations.

Contribution

It demonstrates the importance of q=2k_F scattering processes in Coulomb drag, which were previously overlooked, through combined measurements and calculations.

Findings

Measured drag exceeds RPA calculations significantly.

Drag depends on density difference between layers.

q=2k_F scattering processes are crucial at low densities.

Abstract

Measurements and calculations of Coulomb drag between two low density, closely spaced, two-dimensional electron systems are reported. The experimentally measured drag exceeds that calculated in the random phase approximation by a significant, and density dependent, factor. Studies of the dependence of the measured drag on the difference in density between the two layers clearly demonstrate that previously ignored q=2k_F scattering processes can be very important to the drag at low densities and small layer separations.