Designing Superconductivity: Manipulating Interactions in Arrays of Superconducting Islands

One of the most fundamental questions in physics is how the macroscopic properties of matter emerge from microscopic constituents. Often, complex electronic correlations at the micro-scale act to create remarkable macroscopic materials properties, such as superconductivity and ferromagnetism. But the parameters relevant to understanding and manipulating these correlations are difficult to access. In this talk, I will discuss a “bottom-up” approach to studying collective effects in matter via nanostructured arrays of superconducting islands. We fabricate large arrays of superconducting islands patterned on normal metal films; by changing the size and configuration of the islands, we can to tune the parameters relevant to 2D superconductivity, such as disorder, dissipation, and phase separation. I will discuss electrical transport measurements of these systems, including characterization of the superconducting transitions, vortex dynamics in finite magnetic-fields, and evidence that the system approaches an unusual metallic ground state as the island spacing is increased. I will also discuss the mechanism behind the suppression of superconductivity in individual granular islands, even at large diameters. ​