The minimal nanowire: Mechanical properties of carbyne

Advances in molecular assembly are converging to an ultimate in atomistic precision —nanostructures built by single atoms. Recent experimental studies confirm that single chains of carbon atoms —carbyne— exist in stable polyyne structures and can be synthesized, representing the minimal possible nanowire. Here we report the mechanical properties of carbyne obtained by first-principles–based ReaxFF molecular simulation. A peak Young’s modulus of 288GPa is found with linear stiffnesses ranging from 64.6–5 N/m for lengths of 5–64 Å. We identify a sizedependent strength that ranges from 11GPa (1.3 nN) for the shortest to a constant 8GPa (0.9 nN) for longer carbyne chains. We demonstrate that carbyne chains exhibit extremely high vibrational frequencies close to 6THz for the shortest chains, which are found to be highly length-dependent. Copyright c © EPLA, 201