Large tunable intrinsic gap in rhombohedral-stacked tetralayer graphene

TL;DR

This study demonstrates a large, tunable energy gap in rhombohedral-stacked tetralayer graphene, revealing an interaction-induced insulating state that can be controlled by external fields and temperature.

Contribution

It provides the first direct transport evidence of a large, tunable gap in rhombohedral tetralayer graphene, highlighting the role of electronic interactions.

Findings

Observed an 80 meV energy gap in tetralayer graphene

The gap is enhanced by magnetic field and suppressed by interlayer potential

The insulating state persists up to approximately 40 K

Abstract

In rhombohedral-stacked few-layer graphene, the very flat energy bands near the charge neutrality point are unstable to electronic interactions, giving rise to states with spontaneous broken symmetries. Using transport measurements on suspended rhombohedral-stacked tetralayer graphene, we observe an insulating ground state with a large interaction-induced gap up to 80 meV. This gapped state can be enhanced by a perpendicular magnetic field, and suppressed by an interlayer potential, carrier density, or a critical temperature of ~ 40 K.