Computational study of elastic, structural stability and dynamics properties of penta-graphene membrane

Recently, a new two-dimensional carbon allotrope called Penta-graphene membrane was proposed. The Pentagraphene membrane exhibits interesting mechanical and electronic properties, including typical band gap values of semiconducting materials. Penta-graphene has a Cairo-tiling-like 2D lattice of non coplanar pentagons and its mechanical properties still have not been fully investigated. In this work, we combined reactive molecular dynamics (MD) simulations and density functional theory (DFT) calculations to investigate the mechanical properties and fracture patterns of Penta-graphene membranes under tensile stress. We show that Penta-graphene membranes can hold up to 20% of strain and that fracture occurs only after substantial dynamical bond breaking and the formation of 7, 8 and 11 carbon rings, as well as carbon chains. The stress-strain behavior was observed to follow two regimes, one exhibiting linear elasticity followed by a plastic one, involving carbon atom re-hybridization with the formation of carbon rings and chains.