Energy-driven Drag at Charge Neutrality in Graphene

TL;DR

This paper predicts a new energy-driven Coulomb drag mechanism in graphene heterostructures that dominates near zero doping, with distinctive features like a zero-doping peak and sign reversals, offering new experimental diagnostics.

Contribution

It introduces an energy-driven Coulomb drag mechanism in graphene, highlighting its dominance near zero doping and proposing experimental signatures to distinguish it from momentum drag.

Findings

Energy transfer significantly affects charge transport in graphene layers.

Distinct features like a zero-doping peak and sign reversals are predicted.

The mechanism can be experimentally separated from conventional drag effects.

Abstract

Coulomb coupling between proximal layers in graphene heterostructures results in efficient energy transfer between the layers. We predict that, in the presence of correlated density inhomogeneities in the layers, vertical energy transfer has a strong impact on lateral charge transport. In particular, for Coulomb drag it dominates over the conventional momentum drag near zero doping. The dependence on doping and temperature, which is different for the two drag mechanisms, can be used to separate these mechanisms in experiment. We predict distinct features such as a peak at zero doping and a multiple sign reversal, which provide diagnostics for this new drag mechanism.