On universality in metallic nanocohesion

A semiclassical trace formula for the mesoscopic oscillations of the cohesi ve force in a metallic nanowire of constant cross section is derived. It is shown that the force oscillations are universal. in the sense that their r .m.s. amplitude is independent of the area of the cross section, only for c ross sections with a continuous one-dimensional symmetry. For a wire of rec tangular cross section, the r.m.s. amplitude of the force oscillations is s hown to be proportional to the aspect ratio of the cross section. (C) 2000 Elsevier Science B.V. All rights reserved.