Evidence for non-conservative current-induced forces in the breaking of Au and Pt atomic chains

Abstract

This experimental work aims at probing current-induced forces at the atomic scale. Specifically it addresses predictions in recentwork regarding the appearance of run-away modes as a result of a combined effect of the non-conservative wind force and a 'Berryforce'. The systems we consider here are atomic chains of Au and Pt atoms, for which we investigate the distribution of break downvoltage values. We observe two distinct modes of breaking for Au atomic chains. The breaking at high voltage appears to behave asexpected for regular break down by thermal excitation due to Joule heating. However, there is a low-voltage breaking mode that hascharacteristics expected for the mechanism of current-induced forces. Although a full comparison would require more detailedinformation on the individual atomic configurations, the systems we consider are very similar to those considered in recent modelcalculations and the comparison between experiment and theory is very encouraging for the interpretation we propose.