Atomistic simulations were performed for cylindrical multi-shell type nanowires containing defects. The investigation revealed physical properties that had not been detected in previous studies which had considered only defect-free nanowires. Because the vacancy formation energy was lowest in the core of a cylindrical multi-shell type nanowire, a vacancy which formed in the outer shell of such a nanowire naturally migrated towards the core. The maximum formation energy of an adhered atom on the surface of a cylindrical multi-shell type nanowire was modelled by using a 16-11-6-1 nanowire. The formation energy of an adhered atom decreased when the diameter of the

nanowire was above or below the diameter of the peak-energy maximum. Three recombination mechanisms were found for the vacancy-adhered atom pairs. These were: direct recombination, kick-in recombination and ring recombination. Vacancy formation energy calculations showed that an onion-like cluster with a hollow was formed, and molecular dynamics simulations of various cylindrical multi-shell type nanowires showed that vacancies migrated towards the core.

Defects in Ultra-Thin Copper Nanowires - Atomistic Simulations. J.W.Kang, J.J.Seo, K.R.Byun, H.J.Hwang: Physical Review B, 2002, 66[12], 125405 (8pp)