Design of new superconducting materials, and point-contact spectroscopy as a probe of strong electron correlations

At this centenary of the discovery of superconductivity, the design of new and more useful superconductors remains as enigmatic as ever. These materials play crucial roles both for fundamental science and applications, and they hold great promise in addressing our global energy challenge. The recent discovery of a new class of high-temperature superconductors has made the community more enthusiastic than ever about finding new superconductors. Historically, these discoveries were almost completely guided by serendipity, and now, researchers in the field have grown into an enthusiastic global network to find a way, together, to predictively design new superconductors. After a short history of discoveries of superconducting materials, we share our own guidelines for searching for hightemperature superconductors. Finally, we show how pointcontact spectroscopy (PCS) is used to detect strong correlations in the normal state, with a focus on the normal state region of the Fe-based superconductors, defining a new region in the phase diagram of Ba(Fe_1-xCo _x)₂As₂.