Insulating State in Low-Disorder Graphene Nanoribbons

Abstract

Quantum transport measurements on etched graphene nanoribbons encapsulated in hexagonal boron nitride (hBN) are reported. At zero magnetic field, the devices behave qualitatively very similar to those reported for graphene nanoribbons on SiO2 or hBN, but exhibit a considerably smaller transport gap. At magnetic fields of around 3 T, the transport behavior changes significantly and is dominated by a much larger energy gap induced by electron–electron interactions which completely suppress the transport. This energy gap increases with a slope in the order of 3–4 meV T−1, reaching values of up to 30 meV at 9 T.