Electronic states of zigzag graphene nanoribbons with edges reconstructed with topological defects

TL;DR

This study investigates how topological defects at the edges of zigzag graphene nanoribbons alter their electronic properties, revealing significant changes in the energy spectrum and density of states due to edge reconstructions.

Contribution

It provides a detailed analysis of the electronic states in graphene nanoribbons with reconstructed edges containing topological defects, highlighting the impact on the energy spectrum and density of states.

Findings

Low-energy spectrum is significantly altered by Stone-Wales edge reconstruction.

DOS at the Fermi level remains non-zero regardless of ribbon width.

Edge reconstructions with pentagons and heptagons open an energy gap, affecting electronic properties.

Abstract

The energy spectrum and electronic density of states (DOS) of zigzag graphene nanoribbons with edges reconstructed with topological defects are investigated within the tight-binding method. In case of the Stone-Wales zz (57) edge the low-energy spectrum is markedly changed in comparison to the pristine zz edge. We found that the electronic DOS at the Fermi level is different from zero at any width of graphene nanoribbons. In contrast, for ribbons with heptagons only at one side and pentagons at another one the energy gap at the Fermi level is open and the DOS is equal to zero. The reason is the influence of uncompensated topological charges on the localized edge states, which are topological in nature. This behavior is similar to that found for the structured external electric potentials along the edges.