Theoretical study of the electromigration wind force for adatom migration at metal surfaces

We present the results of a theoretical investigation of the electromigration wind force for adatom migration in a number of migrator-substrate systems. The theoretical background for our study follows from previous work done on bulk electromigration using the linear-response formalism of Kubo. We treat the electronic structure of the substrate using the layer Korringa-Kohn-Rostoker method, which allows us to examine, not only the general diffusion bias of the migrating ion, but also the variation of the wind force between adsorption sites. The interpretation of our findings in terms of a ballistic model of the wind force is discussed.