The confinement present in a graphene nanoribon is expected to induce an one dimensional electronic structure, closely related to the one already observed in carbon nanotubes. While the rolling vector controls the electronic dispersion in carbon nanotubes, in graphene nanoribbons, the electronic confinement is mainly driven by the crystallographic orientation of the edges, called zigzag or armchair. By applying a pulsed magnetic field, we recently gave evidence by magneto-transport experiments, of the impact of the edge confinement on the Dirac fermions.
Illustration of magnetic confinment in a graphene nanoribbon
Beyond the conductance quantization resulting from the onset of chiral currents at the edges of the ribbons, we unveil an unconventional Landau spectrum, different from the one measured in graphene flakes and revealing the fingerprints of the edge symmetry. These high magnetic field experiments carried on individual nano-ribbons have been favourably compared to theoretical simulations of the electronic band structure of graphene nano-ribbons in the quantum regime. These calculations have developed by Stephan Roche (CIN2, Barcelone) and Alessandro Cresti (IMEP-LAHC, Grenoble).
Stephan Roche (CIN2, Barcelone, Espagne)
Alessandro Cresti (IMEP-LAHC, Grenoble, France)
R. Ribeiro et al, Phys. Rev. Lett. 107, 086601 (2011)