Evidence of electronic cloaking from chiral electron transport in bilayer graphene nanostructures

TL;DR

This paper demonstrates an electronic cloaking effect in bilayer graphene, showing how phase coherent transport and chirality lead to electrons bypassing potential barriers, with implications for pseudospintronics.

Contribution

It provides the first experimental evidence of electronic cloaking in bilayer graphene through phase coherent transport measurements.

Findings

Observation of conductance oscillations with different periodicities

Identification of interference patterns via Fourier analysis

Evidence of evanescent wave coupling enabling cloaking

Abstract

The coupling of charge carrier motion and pseudospin via chirality for massless Dirac fermions in monolayer graphene has generated dramatic consequences, such as the unusual quantum Hall effect and Klein tunneling. In bilayer graphene, charge carriers are massive Dirac fermions with a finite density of states at zero energy. Because of their non-relativistic nature, massive Dirac fermions can provide an even better test bed with which to clarify the importance of chirality in transport measurement than massless Dirac fermions in monolayer graphene. Here, we report an electronic cloaking effect as a manifestation of chirality by probing phase coherent transport in chemical-vapor-deposited bilayer graphene. Conductance oscillations with different periodicities were observed on extremely narrow bilayer graphene heterojunctions through electrostatic gating. Using a Fourier analysis technique, we identified the origin of each individual interference pattern. Importantly, the electron waves on the two sides of the potential barrier can be coupled through the evanescent waves inside the barrier, making the confined states underneath the barrier invisible to electrons. These findings provide direct evidence for the electronic cloaking effect and hold promise for the realization of pseudospintronics based on bilayer graphene.