Self-breaking in planar few-atom Au constrictions for nanometer-spaced electrodes

The authors present results on electromigrated Au nanojunctions broken near the conductance quantum of 77.5 mu S. At room temperature it is found that wires, initially narrowed by an actively-controlled electromigration technique down to a few conductance quanta, continue to narrow after removing the applied voltage. Separate electrodes form as mobile gold atoms continuously reconfigure the constriction. They find, from results obtained on over 300 samples, no evidence for gold cluster formation in junctions broken without an applied voltage, implying that gold clusters may be avoided by using this self-breaking technique. (c) 2007 American Institute of Physics.