Bilayer graphene with single and multiple electrostatic barriers: band structure and transmission

TL;DR

This paper investigates how electrostatic barriers affect the electronic properties of bilayer graphene, revealing a finite energy gap in the dispersion relation and analyzing conductance and density of states.

Contribution

It provides a detailed analysis of band structure and transmission in bilayer graphene with multiple electrostatic barriers, highlighting differences from single-layer graphene.

Findings

Finite energy gap in bilayer graphene at zero bias

Presence of a gap under finite bias conditions

Distinct conductance and density of states compared to single-layer graphene

Abstract

We evaluate the electronic transmission and conductance in bilayer graphene through a finite number of potential barriers. Further, we evaluate the dispersion relation in a bilayer graphene superlattice with a periodic potential applied to both layers. As a model we use the tight-binding Hamiltonian in the continuum approxi- mation. For zero bias the dispersion relation shows a finite gap for carriers with zero momentum in the direction parallel to the barriers. This is in contrast to single-layer graphene where no such gap was found. A gap also appears for a finite bias. Numerical results for the energy spectrum, conductance, and the density of states are presented and contrasted with those pertaining to single-layer graphene.