  We present results on electromigrated Au nanojunctions broken near the
conductance quantum $77.5 \mu$S. At room temperature we find 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. We 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.
