Multicomponent fractional quantum Hall effect in graphene

TL;DR

This paper reports the observation of a robust and hierarchically structured fractional quantum Hall effect in high mobility graphene, revealing strong interactions and SU(4) symmetry in the system's quantum states.

Contribution

It presents the first observation of FQHE in graphene with a unique hierarchy and large energy gaps, highlighting the role of SU(4) symmetry and strongly interacting composite fermions.

Findings

FQHE observed in high mobility graphene devices

FQHE gaps up to 10 times larger than in other semiconductors

Unusual hierarchy suggests strongly interacting composite fermions with SU(4) symmetry

Abstract

We report observation of the fractional quantum Hall effect (FQHE) in high mobility multi-terminal graphene devices, fabricated on a single crystal boron nitride substrate. We observe an unexpected hierarchy in the emergent FQHE states that may be explained by strongly interacting composite Fermions with full SU(4) symmetric underlying degrees of freedom. The FQHE gaps are measured from temperature dependent transport to be up 10 times larger than in any other semiconductor system. The remarkable strength and unusual hierarcy of the FQHE described here provides a unique opportunity to probe correlated behavior in the presence of expanded quantum degrees of freedom.