Electron interaction, charging and screening in grain boundaries in graphene

TL;DR

This paper investigates how grain boundaries in doped graphene affect electronic, transport, and spin properties, revealing diverse behaviors of boundary states and their impact on conductance.

Contribution

It introduces a detailed analysis of grain boundary states in graphene using Hartree and Hubbard models, highlighting their metallic or insulating nature and effects on conductance.

Findings

Boundary states can be metallic or insulating depending on their character.

Charge accumulation and spin polarization vary significantly at grain boundaries.

Conductance is reduced due to enhanced backscattering from the self-consistent potential.

Abstract

Electronic, transport, and spin properties of grain boundaries (GBs) are investigated in electrostatically doped graphene at finite electron densities within the Hartree and Hubbard approximations. We demonstrate that depending on the character of the GBs, the states residing on them can have a metallic character with a zero group velocity or can be fully populated losing the ability to carry a current. These states show qualitatively different features in charge accumulation and spin polarization. We also demonstrate that the semiclassical Thomas-Fermi approach provides a satisfactory approximation to the calculated self-consistent potential. The conductance of GBs is reduced due to enhanced backscattering from this potential.