Paired Insulators and High Temperature Superconductors

TL;DR

This paper revisits Phil Anderson's negative U center concept, exploring its historical significance and potential future extensions in understanding insulators and high-temperature superconductors.

Contribution

It highlights the importance of Anderson's negative U center in the context of insulators and superconductors and discusses future research directions.

Findings

Negative U centers explain diamagnetism in glasses and amorphous semiconductors

Revisits Anderson's influential but less famous work

Proposes extensions for future research in superconductivity

Abstract

Almost forty years ago, Phil Anderson introduced the negative U center to account for the fact that most glasses and amorphous semiconductors are diamagnetic. This paper has been highly influential, but certainly does not rank among Phil's most famous works. However, focusing on it enables us to reacquaint a younger generation with another of Phil's contributions, and to use this as a springboard to discuss some forward looking extensions that continue to fascinate us.