Novel Shape Memory of Metal Nanowires through Lattice Reorientation

As functional nano building blocks, nanowires are of§great technical importance because of their unique§structures, properties, and potential applications in§nanoscale electronic, photonic, biological, and§chemical devices. These applications require a§fundamental understanding of the structural§characteristics and thermomechanical properties of§nanowires. §This work focuses on the characterization of the§structure and mechanical behavior of metal nanowires.§A novel shape memory effect and pseudoelastic§behavior of metal nanowires are discovered in§molecular dynamics simulations. Specifically, upon§tensile loading and unloading, these wires can§recover elongations of up to 50%, well beyond the§recoverable strains of 5-8% typical for most bulk§shape memory alloys. This novel behavior arises from§a reversible lattice reorientation driven by the high§surface-stress-induced internal stresses at the§nanoscale. It exists over a wide range of temperature§and is associated with response times on the order of§nanoseconds, making the nanowires attractive§functional components for a new generation of§biosensors, transducers, and interconnects in§nano-electromechanical systems.