Melting of graphene clusters

Abstract

Density-functional tight-binding and classical molecular dynamics simulations are used to investigate the structural deformations and melting of planar carbon nano-clusters $C_N$ with N=2-55. The minimum energy configurations for different clusters are used as starting configuration for the study of the temperature effects on the bond breaking/rotation in carbon lines (N$<$6), carbon rings (5$<$N$<$19) and graphene nano-flakes. The larger the rings (graphene nano-flake) the higher the transition temperature (melting point) with ring-to-line (perfect-to-defective) transition structures. The melting point was obtained by using the bond energy, the Lindemann criteria, and the specific heat. We found that hydrogen-passivated graphene nano-flakes (C${}_N$H${}_M$) have a larger melting temperature with a much smaller dependence on its size. The edges in the graphene nano-flakes exhibit several different meta-stable configurations (isomers) during heating before melting occurs.

References in corpus (5)

• The electronic properties of graphene
• Self-passivating edge reconstructions of graphene
• Graphene nanoflakes - structural and electronic properties
• A comparative study of density functional and density functional tight binding calculations of defects in graphene
• Theoretical study of the stable states of small carbon clusters Cn (n = 2-10)