Whispering electrons in graphene

(Nanowerk Information) Whispering gallery modes (WGMs) are fairly widespread in acoustics and optics. They denote the guided waves circulating alongside a concave floor, the seminal instance being the whispering galleries of St. Paul’s cathedral: somebody whispering on one facet of the gallery could be heard all alongside the circumference of the gallery due to WGMs. The optical counterparts of those WGMs resonances are already exploited in detectors delicate to a single virus. Nevertheless, they’ve been a lot much less explored in digital programs. Contributing to this matter, researchers now have devised a movable round cavity, created by the biased sharp tip of an atomic power microscope, in a graphene sheet (Nano Letters, “Graphene Whisperitronics: Transducing Whispering Gallery Modes into Digital Transport”). Graphical summary of this work. (© Nano Letters) The cavity hosts the resonating digital WGMs modes, that are chosen and controlably coupled (or “transduced”) to conducting channels within the graphene sheet by shifting the tip. This work constitutes an additional step in direction of “Dirac fermion optics”, exploiting the peculiar traits of massless cost carriers in graphene. A big a part of the experimental work was carried out by Boris Brun, within the group of Benoit Hackens on the time of the experiments, with contributions from Christoph Stampfer’s group at RWTH Aachen for the system fabrication, and Jean-Christophe Charlier’s group for the simulations.