Enhancing superconductivity with resonant anti-shielding and topological plasmon-polarons

TL;DR

This paper predicts a fourfold increase in the critical temperature of MgB₂ superconductivity when coupled with a topological crystal, due to dynamic resonant anti-shielding effects involving plasmon polarons.

Contribution

It introduces a novel mechanism for superconductivity enhancement via resonant anti-shielding and demonstrates its universality across superconductor-topological crystal systems.

Findings

Superconducting T_c can be significantly increased by coupling with topological crystals.

Resonant anti-shielding by plasmon polarons is key to the enhancement.

The effect depends strongly on Coulomb coupling, with a maximum at a critical value.

Abstract

By employing ab initio Migdal-Eliashberg calculations, we predict a 4-fold enhancement of the superconducting critical temperature of MgB$_{2}$ when proximity-coupled to the topological crystal Bi$_{2}$Se$_{3}$. We support this result with calculations using the general Leavens scaling method. We show that this effect is a result of dynamic resonant anti-shielding of Cooper pairs by plasmon polarons of Dirac electrons in the topological crystal. Our calculations show that such superconductivity enhancement varies strongly with Coulomb coupling between plasmon polarons and Cooper pairs, with a pronounced maximum of $\textit{T}_{c}$ at a critical value of the coupling parameter. This feature is universal, and so can occur in other superconductor-topological crystal combinations, including with non-phonon mediated superconductors. We discuss methods to experimentally optimize the key coupling parameter.