What Is Armchair-Zigzag Grain Boundary Structure in Graphene?

TL;DR

This paper introduces a novel global optimization method to identify the most stable grain boundary structures in graphene, revealing two new low-energy configurations with improved mechanical and electronic properties.

Contribution

A new differential evolution-based optimization approach was applied to discover previously unknown, lower-energy grain boundary structures in graphene.

Findings

Identified two new grain boundary structures with lower formation energy.

New structures exhibit better mechanical properties under strain.

Distinct STM features differentiate the new models from previous ones.

Abstract

We have developed a new global optimization method for the determination of interface structure based on the differential evolution algorithm. Here, we applied this method to search for the ground state atomic structures of the grain boundary between the armchair and zigzag oriented graphene. We find two new grain boundary structures with considerably lower formation energy of about 1 eV/nm than that of the previously widely used structural models. These newly predicted structures show better mechanical property under external uniaxial strain, and distinguishable scanning tunneling microscope features, compared with the previous structural models. Our results provide important new information for the determination of grain boundary structures and henceforth the electronic properties of defected graphene.