Universality in metallic nanocohesion: A quantum chaos approach

Convergent semiclassical trace formulas for the density of states and the c ohesive force of a narrow constriction in an electron gas, whose classical motion is either chaotic or integrable, are derived. It is shown that mode quantization in a metallic point contact or nanowire leads to universal osc illations in its cohesive force: the amplitude of the oscillations depends only on a dimensionless quantum parameter describing the crossover from cha otic to integrable motion, and is of order 1 nN, in agreement with recent e xperiments.