Manipulating electron waves in graphene using carbon nanotube gating

TL;DR

This paper demonstrates how gating graphene with carbon nanotubes creates electron waveguides that enable precise control of electron waves, with potential applications in quantum interference and electron optics.

Contribution

It introduces a novel method of using carbon nanotube gating to form sharp, tunable electron waveguides in graphene, enabling new electron manipulation techniques.

Findings

Sharp conductance plateaus observed in CNT-gated graphene

Proposed applications in Aharonov-Bohm and two-path interferometers

Versatile approach extendable to other 2D materials

Abstract

Graphene with its dispersion relation resembling that of photons offers ample opportunities for applications in electron optics. The spacial variation of carrier density by external gates can be used to create electron waveguides, in analogy to optical fiber, with additional confinement of the carriers in bipolar junctions leading to the formation of few transverse guiding modes. We show that waveguides created by gating graphene with carbon nanotubes (CNTs) allow obtaining sharp conductance plateaus, and propose applications in the Aharonov-Bohm and two-path interferometers, and a pointlike source for injection of carriers in graphene. Other applications can be extended to Bernal-stacked or twisted bilayer graphene or two-dimensional electron gas. Thanks to their versatility, CNT-induced waveguides open various possibilities for electron manipulation in graphene-based devices.