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 controllably change the superconducting correlations and thus the properties of the system. I will discuss electrical transport measurements of these systems, including characterization of the superconducting transitions, vortex dynamics in a finite magnetic-field, and evidence that the system approaches unusual metallic ground states as the island spacing is increased. This project directly explores the effects of microscopic parameters—such as correlation lengths, island size, and disorder—on macroscopic phenomena in a correlated system, and is relevant to understanding the exotic phases (e.g., the “pseudogap” in high-temperature superconductors) observed in bulk correlated materials.

Nb islands [orange] on Au substrate [yellow];arrows show superconducting phase correlations