Graphene whisperitronics: transducing whispering gallery modes into electronic transport

When confined in circular cavities, graphene relativistic charge carriers occupy whispering gallery modes (WGM) in analogy to classical acoustic and optical fields. The rich geometrical patterns of the WGM decorating the local density of states offer promising perspectives to devise new disruptive quantum devices. However, exploiting these highly sensitive resonances requires the transduction of the WGMs to the outside world through source and drain electrodes, a yet unreported configuration. Here we create a circular p-n island in a graphene device using a polarized scanning gate microscope tip, and probe the resulting WGMs signatures in in-plane electronic transport through the p-n island. Combining tight-binding simulations and exact solution of the Dirac equation, we assign the measured device conductance features to WGMs, and demonstrate mode selectivity by displacing the p-n island with respect to a constriction. This work therefore constitutes a proof of concept for graphene whisperitronics devices.