Mobility gap and quantum transport in functionalized graphene bilayer

TL;DR

This paper investigates how selective functionalization of sublattices in Bernal graphene bilayers affects their electronic properties, revealing a mobility gap and anomalous conductivity behaviors linked to the bipartite lattice structure.

Contribution

It demonstrates that sublattice-specific functionalization induces a significant mobility gap and anomalous conductivity features in graphene bilayers, highlighting the role of bipartite lattice symmetry.

Findings

A mobility gap of about 0.5 eV forms at sublattice B functionalization.

Conductivity exhibits anomalous behaviors at certain energies.

Properties are linked to the bipartite structure of graphene.

Abstract

In a Bernal graphene bilayer, carbon atoms belong to two inequivalent sublattices A and B, with atoms that are coupled to the other layer by $p_\sigma$ bonds belonging to sublattice A and the other atoms belonging to sublattice B. We analyze the density of states and the conductivity of Bernal graphene bilayers when atoms of sublattice A or B only are randomly functionalized. We find that for a selective functionalization on sublattice B only, a mobility gap of the order of 0.5 eV is formed close to the Dirac energy at concentration of adatoms c > 0.01. In addition, at some other energies conductivity presents anomalous behaviors. We show that these properties are related to the bipartite structure of the graphene layer.