Graphene on a ferromagnetic substrate: instability of the electronic liquid

TL;DR

This paper demonstrates that electron interactions in graphene on a ferromagnetic substrate significantly amplify a magnetoelectronic instability, leading to observable spectral gaps and magnetization distortions.

Contribution

It provides theoretical evidence that electron interactions enhance the instability in graphene on ferromagnetic substrates, making it experimentally detectable.

Findings

Interaction strengthens the electronic instability.

Instability causes a spectral gap in graphene.

Detectable effects are achievable with moderate interactions.

Abstract

We previously show [JETP Letters, {\bf 114}, 763 (2021)] that a graphene sample placed on a ferromagnetic substrate demonstrates a cooperative magnetoelectronic instability. The instability induces a gap in the electronic spectrum and a canting deformation of the magnetization near the graphene-substrate interface. In this paper we prove that the interaction between the electrons in graphene strongly enhances the instability. Our estimates suggest that in the presence of even a moderate interaction the instability can be sufficiently pronounced to be detected experimentally in a realistic setting.