Electronic processes in molecular dynamics simulations of nanoscale metal tips under electric fields

Electronic effects play a crucial role in the temperature evolution of metal parts which have electric currents running through them. The increase in temperature due to resistive heating can cause the melting of metal nanoscale wires creating damage in electric circuits. Likewise, electric currents are also present in sharp features on metal surfaces exposed to high electric fields. The destruction of such tips can lead to vacuum arcs, supplying the neutral species to build up plasma over the surface. To follow the temperature evolution caused by electric currents in such a tip, we developed a new model, based on an existing molecular dynamics code, to include resistive heating and electronic thermal conduction. The results given by the new simulation model are in good agreement with analytical predictions.

Research highlights
► A model for the thermal evolution of a metallic tip under a high electric field.
► The model includes electronic effects not normally found in molecular dynamics.
► Resistive heating due to field electron emission caused by an electric field.
► Cooling due to electronic heat conduction.