Periodic negative differential conductance in a single metallic nanocage

We report a bipolar multiple periodic negative differential conductance (NDC) effect on a single cage-shaped Ru nanoparticle measured using scanning tunneling spectroscopy. This phenomenon is assigned to the unique multiply connected cage architecture providing two (or more) defined routes for charge flow through the cage. This, in turn, promotes a self-gating effect, where electron charging of one route affects charge transport along a neighboring channel, yielding a series of periodic NDC peaks. This picture is established and analyzed here by a theoretical model.