The spin-polarized $\nu=0$ state of graphene: a spin superconductor

TL;DR

This paper proposes that the spin-polarized $ u=0$ state in graphene forms a spin superconductor due to electron-hole pairing, explaining its insulating behavior and ability to carry dissipationless spin current.

Contribution

It introduces the concept of a spin superconductor in graphene's $ u=0$ state, highlighting electron-hole pairing as the mechanism for this novel phase.

Findings

Edge and bulk gaps open in the spin superconductor state

The state is a charge insulator but supports dissipationless spin current

Explains experimental observations of insulating behavior in $ u=0$ graphene

Abstract

We study the spin-polarized $\nu=0$ Landau-level state of graphene. Due to the electron-hole attractive interaction, electrons and holes can bound into pairs. These pairs can then condense into a spin-triplet superfluid ground state: a spin superconductor state. In this state, a gap opens up in the edge bands as well as in the bulk bands, thus it is a charge insulator, but it can carry the spin current without dissipation. These results can well explain the insulating behavior of the spin-polarized $\nu=0$ state in the recent experiments.