Effect of charged line defects on conductivity in graphene: numerical Kubo and analytical Boltzmann approaches

TL;DR

This paper investigates how one-dimensional charged defects affect graphene's electrical conductivity using numerical Kubo simulations and analytical Boltzmann theory, revealing sublinear density dependence and weak screening effects.

Contribution

It provides a combined numerical and analytical study of charge transport in graphene with extended charged defects, highlighting the impact of defect nature on conductivity behavior.

Findings

Conductivity shows sublinear dependence on electronic density.

Weak dependence of conductivity on screening wavelength.

Numerical results align with experimental observations.

Abstract

Charge carrier transport in single-layer graphene with one-dimensional charged defects is studied theoretically. Extended charged defects, considered an important factor for mobility degradation in chemically-vapor-deposited graphene, are described by a self-consistent Thomas-Fermi potential. A numerical study of electronic transport is performed by means of a time-dependent real-space Kubo approach in honeycomb lattices containing millions of carbon atoms, capturing the linear response of realistic size systems in the highly disordered regime. Our numerical calculations are complemented with a kinetic transport theory describing charge transport in the weak scattering limit. The semiclassical transport lifetimes are obtained by computing scattered amplitudes within the second Born approximation. The transport electron-hole asymmetry found in the semiclassical approach is consistent with the Kubo calculations. In the strong scattering regime, the conductivity is found to be a sublinear function of electronic density and weakly dependent on the Thomas-Fermi screening wavelength. We attribute this atypical behavior to the extended nature of one-dimensional charged defects. Our results are consistent with recent experimental reports.