Coupled effects of size and uniaxial force on phase transitions in copper nanowires
JW Zhu and DN Shi and JJ Zhao and BL Wang, NANOTECHNOLOGY, 21, 185703 (2010).
By means of molecular dynamics simulations, we investigate solid-solid phase transitions between the regular crystalline structure and the unbuckled atomic-sized one in ultrathin copper nanowires under uniaxial elongation and compression. The interatomic potential employed has been verified to be capable of describing the structural and mechanical properties of ultrathin copper nanowires. The coupled effects of size, uniaxial force and relaxing temperature on the transitions have been revealed. Both the reported phase transition from the crystalline structure to the helical one and the unexpected inverse behavior are found. At a relaxing temperature of 900 K, helical structures are dominant for effective diameters less than 0.8 nm, while the uniaxial force may lead to helical-crystalline phase transitions for thicker ones. We also observe that the transition from a helical 12-7-1 nanowire to a crystalline 110 nanowire is much easier than the inverse transition. Our results demonstrate the structural phase transitions between the crystalline structures and the unbuckled atomic-sized ones of the force-suspended metal nanowires.
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