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

TL;DR

This paper reviews the history and current strategies for designing new superconducting materials, emphasizing the role of point contact spectroscopy in probing strong electron correlations, especially in Fe-based superconductors.

Contribution

It introduces guidelines for predicting high-temperature superconductors and demonstrates how PCS can detect strong correlations in the normal state of Fe-based superconductors.

Findings

PCS reveals strong correlations in Ba(Fe1-xCox)2As2

New phase diagram region identified for Fe-based superconductors

Guidelines for designing high-temperature superconductors proposed

Abstract

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 high-temperature superconductors. Finally, we show how point contact spectroscopy (PCS) is used to detect strong correlations in the normal state with a focus on the strongly-correlated region in the normal state of the Fe-based superconductors, defining a new region in the phase diagram of Ba(Fe1-xCox)2As2.