Formation of gold composite nanowires using cold welding: a structure-based molecular dynamics simulation

The synthesis of composite nanowires has recently emerged to be an important topic in the field of low-dimension nanostructures, and molecular dynamics (MD) simulation proves an effective way to figure out their mechanical properties and is thus adopted to explore the cold welding process of gold nanowires with single-crystalline, fivefold twinned and particularly polycrystalline structure. Four samples of nanowires were successfully welded through limited loadings with similar stress-time responses toward cold welding. The stress shows a low average value during welding with oscillations, indicating the existence of relaxation stages. Herein, the number of defects in the welded nanowires could be controlled by varying the loading time. These findings are expected to open an avenue towards the use of cold welding technology, including welding between materials with various properties, for the bottom-up nanofabrication and nanoassembly techniques without introducing defects.