Thoughts about boosting superconductivity

TL;DR

This paper explores how tuning materials near structural instability can significantly enhance superconducting critical temperatures by modifying the effective electron-electron interactions.

Contribution

It generalizes DeGennes' model by including the elastic response of the background and solves the BCS gap equation for this modified interaction.

Findings

Superconducting critical temperature is strongly enhanced near structural instability.

Including elastic response modifies the effective interaction.

The model provides insights into tuning superconductivity via structural properties.

Abstract

In a superconductor electrons form pairs despite the Coulomb repulsion as a result of an effective attractive interaction mediated by, for example phonons. In the present paper DeGennes' description of the dynamically screened Coulomb interaction is adopted for the effective interaction. This model is generalized by including the elastic response of the charge-compensating background and the BCS gap equation is solved for the resulting effective electron-electron interaction. It is demonstrated that the superconducting critical temperature becomes strongly enhanced when the material is tuned close to a structural instability.