Electronic structure of negatively curved graphene

TL;DR

This paper investigates how topological defects like sevenfolds and eightfolds affect the electronic structure of graphene, revealing that certain defect configurations lead to a zero density of states at the Fermi level.

Contribution

It introduces a gauge field-theory model to analyze electronic properties of negatively curved graphene with specific topological defects.

Findings

Density of states at Fermi energy is zero for most defect configurations.

Two sevenfold defects with non-zero translational factor show non-zero density of states.

The model treats graphene with defects as a negative cone surface with infinite Gaussian curvature.

Abstract

We study the electronic structure of graphene in the presence of either sevenfolds or eightfolds by using a gauge field-theory model. The graphene sheet with topological defects is considered as a negative cone surface with infinite Gaussian curvature at the center. The density of electronic states is calculated for a single seven- and eightfold as well as for a pair of sevenfolds with different morphology. The density of states at the Fermi energy is found to be zero in all cases except two sevenfolds with translational factor $M\neq 0$.