Simulation of Joule annealing in nanoscale Pt wires

Joule heating has been observed to cause a reversible change in resistance in gold nanowires followed by a non-reversible change in resistance due to electromigration. Recently, an irreversible change in resistance has been observed to occur in platinum nanowires even before the onset of electromigration. In this work, the platinum nanowire is modeled using a realistic polycrystalline structure with an underlying Ohmic resistor network, the power dissipated through which is taken as the source term for the heat equation. The local solution to the heat equation drives a Monte Carlo Potts annealing with an Arrhenius type energy barrier. The parameters used in this model are taken from known material values and the geometry of the system. The results of this model match quantitatively with the recent experiment and show that annealing due to Joule heating is a material dependent phenomenon.