Graphing and Grafting Graphene: Classifying Finite Topological Defects

TL;DR

This paper classifies finite topological defects in graphene using lattice models, identifying key defect types and providing a framework for understanding experimentally observed imperfections.

Contribution

It introduces a lattice-based classification scheme for graphene defects, linking observed STM images to specific defect structures and expanding understanding of defect types.

Findings

Most observed defects are 5-7 ring loops

Identified previously unknown defects as divacancies

Provides a lattice framework for defect classification

Abstract

The structure of finite-area topological defects in graphene is described in terms of both the direct honeycomb lattice and its dual triangular lattice. Such defects are equivalent to cutting out a patch of graphene and replacing it with a different patch with the same number of dangling bonds. An important subset of these defects, bound by a closed loop of alternating 5- and 7-membered carbon rings, explains most finite-area topological defects that have been experimentally observed. Previously unidentified defects seen in scanning tunneling microscope (STM) images of graphene grown on SiC are identified as isolated divacancies or divacancy clusters.