The minimal nanowire: Mechanical properties of carbyne
Center for Materials Science and Engineering, Massachusetts Institute of Technology - 77 Massachusetts Ave., Cambridge, MA, USA
2 Laboratory for Atomistic and Molecular Mechanics, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology - 77 Massachusetts Ave., Room 1-235A&B, Cambridge, MA, USA
Accepted: 16 May 2011
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 288 GPa is found with linear stiffnesses ranging from 64.6–5 N/m for lengths of 5–64 Å. We identify a size-dependent strength that ranges from 11 GPa (1.3 nN) for the shortest to a constant 8 GPa (0.9 nN) for longer carbyne chains. We demonstrate that carbyne chains exhibit extremely high vibrational frequencies close to 6 THz for the shortest chains, which are found to be highly length-dependent.
PACS: 62.25.-g – Mechanical properties of nanoscale systems / 81.05.ub – Fullerenes and related materials / 81.07.-b – Nanoscale materials and structures: fabrication and characterization
© EPLA, 2011