Periodic Barrier Structure in AA-Stacked Bilayer Graphene

TL;DR

This paper investigates electron transport in AA-stacked bilayer graphene with a periodic barrier, revealing conditions for Klein tunneling, multiple Dirac points, and conductance channels, advancing understanding of its electronic properties.

Contribution

It provides a detailed analysis of transmission and conductance in AA-stacked bilayer graphene with periodic barriers, highlighting the role of band structure and Dirac cones.

Findings

Klein tunneling occurs only in gapless band structures at normal incidence.

Multiple Dirac points can form in finite periodic barriers.

Two distinct conductance channels are identified corresponding to different cones.

Abstract

We study the charge carriers transport in an AA-stacked bilayer graphene modulated by a lateral one-dimensional multibarrier structure. We investigate the band structures of our system, that is made up of two shifted Dirac cones, for finite and zero gap. We use the boundary conditions to explicitly determine the transmission probability of each individual cone ($\tau=\pm 1$) for single, double and finite periodic barrier structure. We find that the Klein tunneling is only possible when the band structure is gapless and can occur at normal incidence as a result of the Dirac nature of the quasiparticles. We observe that the band structure of the {barriers} can have more than one Dirac points for finite periodic barrier. The resonance peaks appear in the transmission probability, which correspond to the positions of new cones index like associated with $\tau=\pm 1$. Two conductance channels through different cones ($\tau=\pm 1$) are found where the total conductance has been studied and compared to the cases of single layer and AB-stacked bilayer graphene.