Scattering of electrons by clusters of charged impurities in graphene

TL;DR

This paper investigates how clustering charged impurities on graphene affects electron scattering and resistivity, revealing suppression effects and resonance phenomena that influence electronic transport properties.

Contribution

It introduces a model showing impurity clustering reduces resistivity contributions and highlights resonance effects when cluster size exceeds the Fermi wavelength.

Findings

Clustering suppresses impurity contribution to resistivity.

Resonance peaks occur in scattering cross section for large clusters.

Transport cross section can be much smaller than quantum cross section.

Abstract

It is shown that clustering of charged impurities on graphene can suppress their contribution to the resistivity by a large factor of about the number of impurities per cluster, while leaving the density dependence unchanged. If the cluster size is large in comparison with the Fermi wavelength, the scattering cross section shows sharp resonances as a function of incident angle and electron wavevector. In this regime, due to dominant contribution of scattering by small angles, the transport cross section can be much smaller than the quantum one, which can be verified experimentally by comparing the Dingle temperature and the electron mean free path.