Stability of multivacancies in graphene

TL;DR

This study investigates the stability of multivacancies in graphene using DFT calculations, revealing that armchair complementary figures are more stable than zigzag ones for higher orders, influenced by pentagonal ring positions and magnetic factors.

Contribution

It provides a detailed analysis of multivacancy stability in graphene, highlighting the role of complementary figure type and structural factors, which was not extensively studied before.

Findings

Armchair complementary figures are more stable than zigzag ones for vacancies larger than order 5.

Stability is influenced by the positions of pentagonal rings in the defect structure.

Magnetic arrangements and steric hindrance also affect multivacancy stability.

Abstract

The stability of graphene multivacancy systems is studied using Density Functional Theory (DFT) calculations. This work describes the evolution of the energy of formation per carbon atom for zigzag and armchair complementary figures -i.e. the figure formed by the carbon atoms extracted from graphene to form the vacancy-. Multivacancy systems formed when armchair complementary figures are removed are more stable for higher orders (>5) in comparison with the zigzag ones. The case of the construction of a 6-order vacancy from a 5-order one (branch-like) is discussed with the dependence on the place where the extra carbon atom is removed from graphene. The stability of multivacancy systems could be explained through the relative positions of the pentagonal rings present in the resulting defected graphene structure, as the more relevant factor. Other secondary factors that affect the stability of a graphene multivacancy system are the dangling bonds magnetic arrangements and their steric hindrance.