Electron-Hole Symmetry Breaking in Charge Transport in Nitrogen-Doped Graphene

TL;DR

This study investigates how nitrogen doping in graphene causes electron-hole asymmetry in charge transport, revealing distinct scattering mechanisms and their temperature dependence, with implications for electronic and valleytronic applications.

Contribution

It provides the first detailed analysis of electron-hole asymmetry in nitrogen-doped graphene's transport properties and identifies the role of substitutional nitrogen in intervalley scattering.

Findings

Nitrogen dopants introduce atomically sharp scatterers for electrons.

Long-range Coulomb scattering dominates for holes.

Electron-hole asymmetry arises from differences in intervalley scattering.

Abstract

Graphitic nitrogen-doped graphene is an excellent platform to study scattering processes of massless Dirac fermions by charged impurities, in which high mobility can be preserved due to the absence of lattice defects through direct substitution of carbon atoms in the graphene lattice by nitrogen atoms. In this work, we report on electrical and magnetotransport measurements of high-quality graphitic nitrogen-doped graphene. We show that the substitutional nitrogen dopants in graphene introduce atomically sharp scatters for electrons but long-range Coulomb scatters for holes and, thus, graphitic nitrogen-doped graphene exhibits clear electron-hole asymmetry in transport properties. Dominant scattering processes of charge carriers in graphitic nitrogen-doped graphene are analyzed. It is shown that the electron-hole asymmetry originates from a distinct difference in intervalley scattering of electrons and holes. We have also carried out the magnetotransport measurements of graphitic nitrogen-doped graphene at different temperatures and the temperature dependences of intervalley scattering, intravalley scattering and phase coherent scattering rates are extracted and discussed. Our results provide an evidence for the electron-hole asymmetry in the intervalley scattering induced by substitutional nitrogen dopants in graphene and shine a light on versatile and potential applications of graphitic nitrogen-doped graphene in electronic and valleytronic devices.