Elementary process of electromigration at metal nanojunctions in the ballistic regime

We have investigated electromigration process at metal nanojunctions as small as several tens of atoms and found that the elementary process of electromigration in such nanojunctions is the self-diffusion of metal atoms driven by microscopic kinetic energy transfer from single conduction electrons to single metal atoms. We have also shown that metal nanojunctions are stable and can support extremely high current densities of over 10¹⁰ A/cm², as long as the junction voltage is below the critical value.