Effect of disorder on the electronic properties of graphene: a theoretical approach

TL;DR

This paper investigates how different types of disorder affect the electronic properties of graphene, revealing significant modifications in band structure and density of states through a theoretical tight-binding approach.

Contribution

It introduces a theoretical method to analyze the effects of both diagonal and off-diagonal disorder on graphene's electronic structure, including the impact on Dirac cones and band discontinuities.

Findings

Off-diagonal disorder causes asymmetries in the band structure.

Disorder broadening significantly affects electron scattering and lifetime.

The approach can be applied to other 2D materials like boron nitride.

Abstract

In order to manipulate the properties of graphene, its very important to understand the electronic structure in presence of disorder. We investigate, within a tight-binding description, the effects of disorder in the on-site (diagonal disorder) term in the Hamiltonian as well as in the hopping integral (off-diagonal disorder) on the electronic dispersion and density of states by augmented space recursion method. Extrinsic off-diagonal disorder is shown to have dramatic effects on the two-dimensional Dirac-cone, including asymmetries in the band structures as well as the presence of discontinuous bands in certain limits. Disorder-induced broadening, related to the scattering length (or life-time) of electrons, is modified significantly with the increasing strength of disorder. We propose that our theory is suitable to study the effects of disorder in other 2D materials, e.g., a boron nitride monolayer.