Frictional magneto-Coulomb drag in graphene double-layer heterostructure

TL;DR

This paper investigates the magneto- and Hall-drag effects in graphene double layers separated by hBN under strong magnetic fields, revealing how Coulomb interactions and Landau level filling influence drag signals.

Contribution

It provides the first quantitative correlation between magneto-drag resistivity and Landau level filling in graphene heterostructures under high magnetic fields.

Findings

Large magneto- and Hall-drag signals observed.

Sign and magnitude of drag relate to Landau level filling.

Weak temperature dependence and quadratic magnetic field dependence explained by Coulomb scattering.

Abstract

Coulomb interaction between two closely spaced parallel layers of electron system can generate the frictional drag effect by interlayer Coulomb scattering. Employing graphene double layers separated by few layer hexagonal boron nitride (hBN), we investigate density tunable magneto- and Hall-drag under strong magnetic fields. The observed large magneto-drag and Hall-drag signals can be related with Laudau level (LL) filling status of the drive and drag layers. We find that the sign and magnitude of the magneto- and Hall-drag resistivity tensor can be quantitatively correlated to the variation of magneto-resistivity tensors in the drive and drag layers, confirming a theoretical formula for magneto-drag in the quantum Hall regime. The observed weak temperature dependence and $\sim B^2$ dependence of the magneto-drag are qualitatively explained by Coulomb scattering phase-space argument.