Dynamic Characterization of the Postbreaking Behavior of a Nanowire

Abstract

The dynamic evolution of a gold nanojunction has been investigated by incorporation of molecular dynamics (MD) simulation and mechanically controllable break junction (MCBJ) in a wide range of strain rates, covering nonequilibrium, quasi-equilibrium, and equilibrium tensile states. Theoretical simulations corresponding to the nonequilibrium and quasi-equilibrium states demonstrated that the metallic nanojunction spontaneously grew in the time scale of ∼1 ns. In the final stage, the gap increment revealed a unique stepwise feature, corresponding to the atomic-resolved tip reconstruction. When strain rate varied from 489.6 to 0.245 m/s, the gap was reduced from 4.0 to 1.3 nm. In the regime of equilibrium stretching, i.e., several nanometers per second, the experimental MCBJ results gave a mean gap size of 0.4 ± 0.1 nm, which showed less strain rate dependence. This value corresponded well to the absolute value of the stepwise increment of the gap due to the local tip recrystallization as estimated by the MD simulation. The agreement between theoretical modeling and experimental measurement demonstrates that the combination is a good strategy in nanoscience.