Introducing strong correlation effects into graphene by gadolinium intercalation

TL;DR

This paper demonstrates that gadolinium intercalation in graphene induces strong electronic correlations, leading to flat bands, polaron formation, and potential ordered ground states, advancing the understanding of correlation effects in 2D materials.

Contribution

It introduces a method to strongly dope graphene via Gd intercalation, revealing correlation-driven phenomena like flat bands and polaron replicas not previously observed.

Findings

Development of flat bands due to electronic correlations

Observation of polaron replica bands from electron-phonon coupling

Enhanced stability and homogeneity of Gd-intercalated graphene

Abstract

Exotic ordered ground states driven by electronic correlations are expected to be induced in monolayer graphene when doped to the Van Hove singularity. Such doping levels are reached by intercalating Gd in graphene on SiC(0001), resulting in a strong homogeneity and stability. The electronic spectrum now exhibits severe renormalizations. Flat bands develop which is driven by electronic correlations according to our theoretical studies. Due to strong electron-phonon coupling in this regime, polaron replica bands develop. Thus, interesting ordered ground states should be made accessible.