Critical fracture strain of carbyne-graphene nanoelements: influence of temperature and strain rate

Abstract A theoretical framework describing the atomistic influence of temperature and strain rate on the strength of nanoelements composed of combinations of one- and two-dimensional structures are developed. In particular, carbyne–graphene nanoelements (CGNs), consisting of graphene sheets connected by a carbyne chain lying in the plane of these sheets, are considered. A fluctuation-based strength model is proposed, demonstrating that temperature and strain rate effects are governed by fluctuation-induced rupture of contact bonds. The dependencies of CGN strength on temperature and strain rate are obtained and verified by molecular dynamics simulations using the machine-learning based atomic cluster expansion (ML-ACE) potential. It is shown that the temperature sensitivity of CGN strength is comparable to that of graphene but significantly lower than that of metallic nanowires, due to the high stiffness of sp-bonds. The relatively weak dependence of strength on temperature and strain rate highlights the potential of CGNs for applications in straintronic devices.