Propagating Plasmons in a Charge-Neutral Quantum Tunneling Transistor

A. Woessner, A. Misra, Y. Cao, I. Torre, A. Mishchenko, M. B. Lundeberg, K. Watanabe, T. Taniguchi, M. Polini, K. S. Novoselov and F. H. L. Koppens

ACS Photonics, Article ASAP (2017)
The ultimate limit of control of light at the nanoscale is the atomic scale. By stacking multiple layers of graphene on hexagonal boron nitride (h-BN), heterostructures with unique nanophotonic properties can be constructed, where the distance between plasmonic materials can be controlled with atom-scale precision. Here we show how an atomically thick tunable quantum tunnelling device can be used as a building block for quantum plasmonics. The device consists of two layers of graphene separated by 1 nm (three monolayers) of h-BN, and a bias voltage between the layers generates an electron gas coupled to a hole gas. We show that, even though its total charge is zero, this system is capable of supporting propagating graphene plasmons.