Controlled electromigration in Al and Au nanoconstrictions - Towards the study of sub-10 nm superconducting nanostructures

By applying high current density to a nanowire, it is possible to induce atomic migration resulting from the momentum transfer by the charge carriers. This phenomenon is known as electromigration. In this work, we present successful preliminary results of controlled electromigration in thin Al and Au transport microbridges with predefined structures (constricted nanowires and Dayem bridges). We discuss the conditions necessary to achieve electromigration, the ingredients of the feedback loop control, and present the electrical properties and stability of the nanostructures achieved by this method. This research is a first step towards the use of electromigration for elaborating nanostructures at sub-10 nm scale. The use of superconducting samples would allow us to study some theoretical predictions as the increase of superconducting critical temperature [1] or the appearance of quantum phase slips [2,3].