Superconductivity Induced by Interfacial Coupling to Magnons

TL;DR

This paper proposes a mechanism for inducing p-wave superconductivity in a normal metal sandwiched between ferromagnetic insulators via electron-magnon interactions at the interfaces, with estimated critical temperatures for specific material trilayers.

Contribution

It introduces a novel interfacial coupling mechanism that can induce p-wave superconductivity in normal metals using magnon interactions from adjacent ferromagnetic insulators.

Findings

Superconductivity can be induced at 1-10 K in YIG-Au-YIG trilayers.

EuO-Au-EuO trilayers exhibit superconductivity below 1 K.

Numerical solutions of the gap equation estimate critical temperatures for different material configurations.

Abstract

We consider a thin normal metal sandwiched between two ferromagnetic insulators. At the interfaces, the exchange coupling causes electrons within the metal to interact with magnons in the insulators. This electron-magnon interaction induces electron-electron interactions, which, in turn, can result in p-wave superconductivity. In the weak-coupling limit, we solve the gap equation numerically and estimate the critical temperature. In YIG-Au-YIG trilayers, superconductivity sets in at temperatures somewhere in the interval between 1 and 10 K. EuO-Au-EuO trilayers require a lower temperature, in the range from 0.01 to 1 K.