Healing of a Topological Scar: Coordination Defects in a Honeycomb Lattice

Abstract

A crystal structure with a point defect typically returns to its ideal local structure upon moving a few bond lengths away from the defect; topological defects such as dislocations or disclinations also heal rapidly in this regard. Here we describe a simple point defect -- a two-fold atom incorporated at the growth edge of a 2D hexagonal honeycomb material -- whose healing may require a defect complex with 50 or more atoms. $\text{Topologically}$ the two-fold atom disappears into a single 'long bond' between its neighbors, thereby inducing a pentagonal disclination. However, $\text{chemically}$ this disclination occupies as much physical space as a six-fold ring. This incompatibility of chemistry and topology can cause a ''ringing'' of the Gaussian curvature that creates an expansive healing region and may even spawn a semi-infinite grain boundary propagating outwards from the topological scar.

4 pages, 3 figures; SI is 7 pages, 4 figures, 1 table. Ancillary files include a 7-zip file with particle positions, excel/csv files with structure energies, and movies (explained in the SI) of the simulation process

References in corpus (3)

• Topological Defects in Graphene: Dislocations and Grain Boundaries
• Chemical functionalization of graphene with defects
• Grain Boundary Structures and Collective Dynamics of Inversion Domains in Binary Two-Dimensional Materials