Giant magneto-drag in graphene at charge neutrality

TL;DR

This paper investigates giant magneto-drag effects in graphene near charge neutrality, revealing how electron-hole coexistence and magnetic fields influence Coulomb drag and Hall drag phenomena.

Contribution

It provides experimental data and theoretical insights into magneto-drag behavior in graphene, highlighting the role of charge neutrality and current decoupling.

Findings

Giant increase in drag resistivity near charge neutrality

Observation of non-zero Hall drag away from neutrality

Dependence of magneto-drag sign on energy relaxation and geometry

Abstract

We report experimental data and theoretical analysis of Coulomb drag between two closely positioned graphene monolayers in weak magnetic field. Close enough to the neutrality point, coexistence of electrons and holes in each layer leads to a dramatic increase of the drag resistivity. Away from charge neutrality, we observe non-zero Hall drag. The observed phenomena are explained by decoupling of electric and quasiparticle currents which are orthogonal at charge neutrality. The sign of magneto-drag depends on the energy relaxation rate and geometry of the sample.