Formation and Evolution of Single Molecule Junctions
arXiv:0901.1134 · doi:10.1103/PhysRevLett.102.126803
Abstract
We analyze the formation and evolution statistics of single molecule junctions bonded to gold electrodes using amine, methyl sulfide and dimethyl phosphine link groups by measuring conductance as a function of junction elongation. For each link, maximum elongation and formation probability increase with molecular length, strongly suggesting that processes other than just metal-molecule bond breakage play a key role in junction evolution under stress. Density functional theory calculations of adiabatic trajectories show sequences of atomic-scale changes in junction structure, including shifts in attachment point, that account for the long conductance plateau lengths observed.
10 pages, 4 figures, submitted