Coulomb blockade phenomena in electromigration break junctions

Nanosized gap structures have been fabricated via electromigration-induced breaking of gold-palladium nanowires. The application of low breaking voltages resulted in gap junctions exhibiting single-electron tunneling signatures at low temperature (2K), which are attributed to the formation of metallic nanoclusters during the electromigration process. Strikingly, the I–V characteristics of most samples displayed a close similarity to those typically attributed to electrical transport through single molecules contacted by incorporation into electromigration gaps. The finding that the breaking of bare nanowires alone is sufficient to create rich differential conductance features should be taken into account in future electrical studies on molecular-scale structures.