Molecular dynamic simulation of the temperature effect on strength of carbyne-graphene nanoelements

The results of study of the temperature effect on strength of carbyne-graphene nanoelement (CGN) over a wide temperature range using the molecular dynamics technique are presented. The investigated CGN consisted of two graphene sheets connected by a ten-atom carbyne chain. It was ascertained that at temperatures lower than 1000 K, the average value of CGN strength decreases monotonically with increasing temperature according to a nearly linear dependence, and is accompanied by a scatter of strength values. This scatter increases as the temperature grows. It is shown that these regularities are due to the fluctuation-induced mechanism of the contact bonds breaking in carbene-graphene nanoelement. For the first time, it was found the phenomenon of transition from the instability of carbyne-graphene nanoelements due to the contact bond breaking to the instability, as a result of the fluctuation-induced formation of a Stone-Wales-like defect with the subsequent pulling out of the chain from the graphene sheet. This phenomenon is observed at temperatures higher than 1000 K. The obtained results may be used both for substantiating the working temperatures of CGN-based straintronics, and in the technologies of carbyne chains production.