Observation of Large Intrinsic Gap in Rhombohedral-Stacked Tetralayer Graphene

Few-layer graphene has attracted attention in the scientific community as a novel 2D material due to its observed quantum hall effect, high electronic mobility, high transparency and tensile strength, among other properties. In rhombohedral-stacked few-layer graphene, the very flat band near the charge neutrality point is unstable to electronic interactions, and gives rise to states with spontaneous broken symmetries. Intrinsic gaps of \textasciitilde 2 meV and 40 meV are observed in bilayer and trilayer graphene, respectively. Here, we report the observation of an even larger gap in suspended rhombohedral-stacked tetralayer graphene (r-4LG) samples. We will present the latest data of the evolution of the gapped state with temperature and external fields, and compare with theoretical models.