Two-dimensional Graphene with Structural Defects: Elastic Mean Free Path, Minimum Conductivity and Anderson Transition

TL;DR

This study investigates how structural defects in graphene affect its quantum transport properties, revealing a minimum conductivity plateau and potential for observing Anderson localization at low defect densities.

Contribution

It provides a realistic tight-binding model and computational analysis of defect-induced transport phenomena in graphene, highlighting the minimum conductivity and localization effects.

Findings

Conductivity saturates to a minimum value of 4e^2/{}h at high defect densities.

Quantum interference effects suggest measurable Anderson localization at ~1% defect density.

Strong defect density dependence of mean free path and conductivity.

Abstract

Quantum transport properties of disordered graphene with structural defects (Stone-Wales and divacancies) are investigated using a realistic {\pi}-{\pi}* tight-binding model elaborated from ab initio calculations. Mean free paths and semiclassical conductivities are then computed as a function of the nature and density of defects (using an order-N real-space Kubo-Greenwood method). By increasing of the defect density, the decay of the semiclassical conductivities is predicted to saturate to a minimum value of 4e^2/{\pi}h over a large range (plateau) of carrier density (> 0.5 10^{14}cm^{-2}). Additionally, strong contributions of quantum interferences suggest that the Anderson localization regime could be experimentally measurable for a defect density as low as 1%.