Many-body electron correlations in graphene

TL;DR

This paper explores how high-quality graphene structures can exhibit strong many-body electron correlations, potentially leading to novel quantum phenomena like high-temperature electron-hole superfluidity.

Contribution

It investigates the enhancement of electron correlations in graphene nanostructures and multilayers, highlighting the potential for stabilizing superfluidity at high temperatures.

Findings

Electron nanoribbons exhibit quantum size effects that enhance correlations.

Graphene multilayers can support electron-hole superfluidity.

Strong correlations are achievable in engineered graphene systems.

Abstract

The conduction electrons in graphene promise new opportunities to access the region of strong many-body electron-electron correlations. Extremely high quality, atomically flat two-dimensional electron sheets and quasi-one-dimensional electron nanoribbons with tuneable band gaps that can be switched on by gates, should exhibit new many-body phenomena that have long been predicted for the regions of phase space where the average Coulomb repulsions between electrons dominate over their Fermi energies. In electron nanoribbons a few nanometres wide etched in monolayers of graphene, the quantum size effects and the van Hove singularities in their density of states further act to enhance electron correlations. For graphene multilayers or nanoribbons in a double unit electron-hole geometry, it is possible for the many-body electron-hole correlations to be made strong enough to stabilise high-temperature electron-hole superfluidity.