Microscopic contacts which form spontaneously between two pieces of metal which touch have been shown to exhibit conductance quantization under a wide variety of conditions. Recently, it has been shown that the mechanical properties of such metallic "nanowires" also exhibit interesting quantum-size effects, which are correlated with their electrical properties. In order to describe electrical and mechanical properties of nanoscopic metallic systems within a single theoretical framework, we have developed a scattering approach to nanomechanics. A simple picture of metallic nanocohesion in which conductance channels act as delocalized chemical bonds is derived in the jellium approximation. Universal mesoscopic oscillations of the cohesive force of order 1nN are predicted when a metallic quantum wire is stretched to the breaking point, which are synchronized with quantized jumps in the conductance. These predictions are in quantitative agreement with the pioneering experiment of Rubio, Agrait, and Vieira, who measured simultaneously the force and conductance during the formation and rupture of an atomic-scale gold nanowire.
Significant advances in the theory of metallic nanocohesion were made by applying techniques from quantum chaos.
Find out about the remarkable stability of metal nanowires.
Movies of quantum necking in stressed nanowires.
