Stack of correlated insulating states in bilayer graphene kagome superlattice

TL;DR

This paper demonstrates that dielectric-patterned bilayer graphene with an engineered Kagome superlattice can host multiple correlated insulating states arising from flat electronic bands, offering a tunable platform for exploring strong correlation physics.

Contribution

It introduces a novel dielectric-patterned Kagome superlattice in bilayer graphene, enabling controlled flat-band formation and correlated insulating states beyond traditional moiré systems.

Findings

Correlated insulating states emerge at moderate superlattice potentials.

These states are suppressed at higher temperatures due to thermal effects.

Theoretical calculations confirm multiple flat minibands and band reconstruction.

Abstract

Graphene-based systems have emerged as a rich platform for exploring emergent quantum phenomena-including superconductivity, magnetism, and correlated insulating behavior-arising from flat electronic bands that enhance many-body interactions. Realizing such flat bands has thus far relied primarily on moir\'e graphene superlattices or rhombohedral stacking graphene systems, both of which face challenges in reproducibility and tunability. Here, we introduce an artificial Kagome superlattice in bilayer graphene, engineered via nanopatterning of the dielectric substrate to create a precisely defined and electrostatically tunable periodic potential. Magnetotransport measurements reveal the emergence of a stack of correlated insulating states at moderate superlattice potentials, characteristic of strong electron-electron interactions within Kagome-induced flat bands. As temperature increases, these correlated gaps collapse, signaling the thermal suppression of interaction-driven states. Continuum-model calculations confirm the formation of multiple flat minibands and reproduce the observed evolution of band reconstruction. Our results establish dielectric-patterned graphene superlattices as a robust and controllable architecture for realizing flat-band-induced correlated phenomena beyond moir\'e systems.