Jellium Model of Metallic Nanocohesion

Cohesion in metals is due to the formation of bands, which arise from the overlap of atomic orbitals. In a metallic constriction with nanoscopic cross section, the transverse motion is quantized, leading to a finite number of subbands below the Fermi energy «F. A striking consequence of these discrete subbands is the phenomenon of conductance quantization [1]. The cohesion in a metallic nanoconstriction must also be provided by these discrete subbands, which may be thought of as chemical bonds which are delocalized over the cross section. In this Letter, we confirm this intuitive picture of metallic nanocohesion using a simple jellium model. Universal force oscillations of order «FylF are predicted in metallic nanostructures exhibiting conductance quantization, where lF is the Fermi wavelength. Our results are in quantitative agreement with the recent pioneering experiment of (