Signatures of evanescent mode transport in graphene

TL;DR

This paper calculates shot noise in graphene due to evanescent modes, revealing universal Fano factors that serve as experimental signatures of evanescent transport distinct from disordered metals.

Contribution

It provides theoretical predictions of Fano factors for evanescent mode transport in graphene, offering clear experimental signatures different from disordered metal behavior.

Findings

F = 1/4 for two impurity-free graphene strips at the Dirac point

F = 1/(8 ln 2) for large superlattices of graphene strips

Results differ from F = 1/3 in disordered metals

Abstract

We calculate the shot noise generated by evanescent modes in graphene for several experimental setups. For two impurity-free graphene strips kept at the Dirac point by gate potentials, separated by a long highly doped region, we find that the Fano factor takes the universal value F = 1/4. For a large superlattice consisting of many strips gated to the Dirac point interspersed among doped regions, we find F = 1/(8 ln 2). These results differ from the value F = 1/3 predicted for a disordered metal, providing an unambiguous experimental signature of evanescent mode transport in graphene.