Coulomb Drag of Massless Fermions in Graphene

TL;DR

This paper reports experimental measurements of Coulomb drag in double-layer graphene, revealing Fermi liquid behavior at higher temperatures and giant fluctuations at lower temperatures due to coherent transport and interlayer interactions.

Contribution

It introduces a novel device structure for measuring Coulomb drag in graphene and provides new insights into temperature-dependent fluctuation phenomena.

Findings

Coulomb drag follows Fermi liquid behavior above 50 K

Giant fluctuations emerge at lower temperatures

Interlayer interactions influence coherent transport

Abstract

Using a novel structure, consisting of two, independently contacted graphene single layers separated by an ultra-thin dielectric, we experimentally measure the Coulomb drag of massless fermions in graphene. At temperatures higher than 50 K, the Coulomb drag follows a temperature and carrier density dependence consistent with the Fermi liquid regime. As the temperature is reduced, the Coulomb drag exhibits giant fluctuations with an increasing amplitude, thanks to the interplay between coherent transport in the graphene layer and interaction between the two layers.