Band gap and correlated phenomena in bilayer and trilayer graphene

Abstract

Graphene and its few layer cousins are unique two-dimensional (2D) systems with extraordinary electrical, thermal, mechanical and optical properties, and they have become both fantastic platforms for exploring fundamental processes and some of the most promising material for next generation electronics. Here we present our transport studies of dual gated suspended bilayer and trilayer graphene devices. At the charge neutrality point, application of an electric field induces a gap in bilayer graphene’s band structure. For high mobility bilayer devices, we observe an intrinsic insulating state with a gap of 2-3 meV and a transition temperature ~5K, which arises from electronic interactions. In ABC-stacked trilayer devices, an insulating state with gap ~25 meV is observed. Our results underscore the rich interaction-induced collective states in few layer graphene and suggest a promising direction for THz technology and high speed low dissipation electronic devices.