Spin superconductor in ferromagnetic graphene

TL;DR

This paper proposes a theoretical model for a spin superconductor in ferromagnetic graphene, demonstrating a spin-polarized pairing mechanism, an electric Meissner effect, and a spin-current Josephson effect.

Contribution

It introduces a BCS-type theory for spin superconductivity in ferromagnetic graphene and predicts novel phenomena like the electric Meissner effect and spin-current Josephson effect.

Findings

Existence of a spin superconductor in ferromagnetic graphene.

Prediction of an electric Meissner effect against varying electric fields.

Proposal of a spin-current Josephson effect in SSC junctions.

Abstract

We show a spin superconductor (SSC) in ferromagnetic graphene as the counterpart to the charge superconductor, in which a spin-polarized electron-hole pair plays the role of the spin $2 (\hbar/2)$ `Cooper pair' with a neutral charge. We present a BCS-type theory for the SSC. With the `London-type equations' of the super-spin-current density, we show the existence of an electric `Meissner effect' against a spatial varying electric field. We further study a SSC/normal conductor/SSC junction and predict a spin-current Josephson effect.