Graphene is an intriguing material, but only very clean material reveals the beauty of graphene’s electronic poperties. However, in real devices there is typically a considerable random potential present due to charge impurities in the substrate or adsorbates on graphene itself limiting the transport mobility. To overcome this problem, we suspend graphene and clean it by current annealing yielding graphene with exceptional high nobilities approaching 100 m2/Vs. These suspended devices are ballistic over micrometer length scales and display intriguing interference patterns in the electrical conductance when different gate potentials are applied. Specifically, I will discuss electric graphene devices in which one can study electric analogs of a mirror, a guiding fiber, and Fabry-Perot resonators, well known in optics. There are great similarities between the propagation of light in a dielectric and electrons in graphene, but also differences. In particular, a negative refractive index is straightforward to realize in graphene, but hard in optics.
University of Basel (Suisse)