One-Dimensional Potential in Graphene

With improvements in fabrication techniques, low-disorder graphene devices have been realized to study a variety of correlated physics including fractional quantum Hall effect, and Mott insulating behavior. One possibility for inducing new electronic phenomena is by the use of nanometer-scale one-dimensional potentials to define narrow channels in graphene sheets. Previous efforts to study such effects in graphene have relied on lithographic fabrication of narrow metal gates. Lithographic methods suffer from edge disorder and a resolution limited to tens of nanometers. In this talk, we describe the engineering of a 1D potential in graphene using a carbon nanotube (CNT) that is a few nanometers from the graphene surface. We will describe cryogenic magnetotransport measurements that indicate the presence of a one-dimensional mode in graphene under appropriate gating conditions from the CNT.
Electronic 1D bound states are also predicted to cause plasmonic reflections. These have been observed with cracks, stacking faults, and wrinkles in graphene. Our system provides an ideal platform to probe these reflections with the CNT gate inducing a tunable 1D barrier in graphene. In this talk, we also report near-field optical microscopy measurements probing such plasmonic reflections.