Cloaking Resonant Scatterers and Tuning Electron Flow in Graphene

TL;DR

This paper proposes a method to cloak resonant scatterers in graphene using a gated ring, enabling control over electron flow, with analysis supported by wave-function expansion and tight-binding calculations.

Contribution

It introduces a novel electron cloaking scheme in graphene using a gated ring, applicable to resonant scatterers, and demonstrates robustness against disorder.

Findings

Gated rings can effectively cloak resonant scatterers in graphene.

The cloaking condition is derived from a partial-wave expansion of the Dirac equation.

Cloaking remains effective despite disorder in the gate potential.

Abstract

We consider resonant scatterers with large scattering cross-sections in graphene that are produced by a gated disk or a vacancy, and show that a gated ring can be engineered to produce an efficient electron cloak. We also demonstrate that this same scheme can be applied to tune the direction of electron flow. Our analysis is based on a partial-wave expansion of the electronic wave-functions in the continuum approximation, described by the Dirac equation. Using a symmetrized version of the massless Dirac equation, we derive a general condition for the cloaking of a scatterer by a potential with radial symmetry. We also perform tight-binding calculations to show that our findings are robust against the presence of disorder in the gate potential.