Coulomb drag in intermediate magnetic fields

TL;DR

This paper provides a theoretical analysis of Coulomb drag in coupled 2D electron gases under intermediate magnetic fields, revealing complex dependencies on temperature and magnetic field, and introduces a new magnetoplasmon-based drag mechanism.

Contribution

It introduces a novel mechanism of Coulomb drag involving magnetoplasmon absorption and derives relations for resonant tunneling of magnetoplasmons, expanding understanding of electron interactions in magnetic fields.

Findings

Quantization leads to rich parametric dependence of drag transresistance.

Small energy scales lower excitation energies below temperature.

Linear temperature dependence of transresistance can occur in weak magnetic fields.

Abstract

We investigated theoretically the Coulomb drag effect in coupled 2D electron gases in a wide interval of magnetic field and temperature $ 1/\tau \ll \omega_c \ll E_F/\hbar$, $T \ll E_F$, $\tau$ being intralayer scattering time, $\omega_c$ being the cyclotron frequency. We show that the quantization of the electron spectrum leads to rich parametric dependences of drag transresistance on temperature and magnetic field. This is in contrast to usual resistance. New small energy scales are found to cut typical excitation energies to values lower than temperature. This may lead to a linear temperature dependence of transresistance even in a relatively weak magnetic field and can explain some recent experimental data. We present a novel mechanism of Coulomb drag when the current in the active layer causes a magnetoplasmon wind and the magnetoplasmons are absorbed by the electrons of the passive layer providing a momentum transfer. We derived general relations that describe the drag as a result of resonant tunneling of magnetoplasmons.