Diffusion processes in single-atom electromigration along a gold chain: First-principles calculations

Electromigration of a single atom along a chain of gold atoms was investigated by first-principles calculations based on the nonequilibrium Green's-function technique combined with density-functional theory. In the case of electromigration of a gold atom, we found that the potential barrier along the migration pathway decreases as the applied bias voltage is increased and the migration direction is the same as that of electron flow. By considering the case of electromigration of a sulfur atom along the gold chain, we determined that the electron flow around the migrating atom is responsible for single-atom electromigration. The calculated electromigration rate for the gold atom indicated that the electromigration takes place at temperatures above room temperature.