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Deformation of Top-Down and Bottom-Up Silver Nanowires

I wanted to share some our work on the deformation behavior of metal nanowires that was recently published in Advanced Functional Materials. In this work, we considered the tensile deformation of three experimentally observed silver nanowire geometries, including five-fold twinned, pentagonal nanowires. The manuscript abstract and urls to videos of the tensile deformation of the three nanowire geometries are below. A copy of the manuscript is attached.

Rhombic Nanowire | Truncated-Rhombic Nanowire | Pentagonal Nanowire

Abstract

We employ atomistic simulations to probe the deformation behavior of experimentally observed top-down and bottom-up FCC silver nanowires. We consider stable, <110> oriented nanowires with a rhombic and truncated-rhombic cross section, representative of top-down geometries, as well as the multiply twinned pentagonal nanowire that is commonly fabricated in a bottom-up approach. We simulate the tensile deformation from a stable, experimentally observed structure to failure for each nanowire structure. A detailed, mechanistic explanation of the initial defect nucleation is provided for each nanowire. The three geometries are shown to exhibit different levels of strength and to deform by a range of mechanisms depending on the nanowire structure. In particular, the deformation behavior of top-down and bottom-up nanowires is shown to be fundamentally different. The yield strength of nanowires ranging from 1-25 nanometers in diameter is provided and reveals that in addition to cross sectional diameter, the strength of nanowires is strongly tied to the structure. This study demonstrates that nanowire structure and size may be tailored for specific mechanical requirements in nanometer scale devices.

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PDF icon NanowireDeformation.pdf1.21 MB

Comments

Henry Tan's picture

The quantized nature of deformation in nanowire reveals a disparity in the loading method. If the applied tensile stress is incrementally increased during deformation (force control), the mechanical response exhibits instabilities in strain corresponding to ‘instantaneous’ changes in specimen length due to the motion of internal defects. Conversely, applying an incrementally increasing strain (displacement control) reveals yielding in increments of force (stress) instability attributable to dissipation of stored strain energy through the nucleation and motion of internal defects.

Similar quantized nature of deformation occur in some composite materials with catastrophic interface debonding, as described in the Section 4 of this paper. The threshold of material parameters combination for the occurrence of catastrophic behavior has been obtained analytically in the paper.

Thanks for the comment and paper Henry. 

This work is similar to our recent works on tensile deformation of fivefold twinned nanowires, which has been published in Phys. Rev. B., Vol. 74, 214108, 2006. Our focus in the paper is to reveal the micro-structure hardening mechanism in the unique fivefold copper nanowires.

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