Atomistic Mechanism of Stress-Induced Combined Slip and Diffusion in Sub-5 Nanometer-Sized Ag Nanowires.

With continuous minimization of nanodevices, the dimensions of metallic materials used in nanodevices decrease to a few nanometers. Understanding the structural stability and deformation behavior of these small-sized metallic materials is important for their practical applications. Here we report our atomic-resolution observation of the deformation processes of Ag nanowires with widths of ∼3 nm. The nanowires under tension experienced plastic deformation via partial dislocation activities, which led to deformation twinning in and homogeneous elongation of the nanowires, and surface atom diffusion that reduced the nanowires' width but did not contribute to the nanowire elongation. The diffusion of surface atoms was initiated at surface steps introduced by the partial dislocation activities, leading to fracture of the nanowires with relatively low homogeneous elongation.