Strong Anisotropy in Spin Suceptibility of Superfluid 3He-B Film Caused by Surface Bound States

TL;DR

This paper investigates how surface bound states in superfluid 3He-B films cause strong anisotropic spin susceptibility, with significant enhancement when magnetic field is perpendicular to the film, highlighting the Majorana nature of zero energy states.

Contribution

It demonstrates the anisotropic spin susceptibility in superfluid 3He-B films caused by surface bound states and elucidates the Majorana nature of zero energy bound states.

Findings

Enhanced susceptibility for magnetic field perpendicular to the film

No enhancement for magnetic field parallel to the film

Majorana nature of zero energy bound states

Abstract

Spin susceptibility of superfluid 3He-B film with specular surfaces is calculated. It is shown that, when the magnetic field is applied in a direction perpendiculr to the film, the suseptibility is significantly enhanced by the contribution from the surface bound states. No such enhancement is found for the magnetic field parallel to the film. A simplified model with spatially constant order parameter is used to elucidate the magnetic properties of the surface bound states. The Majorana nature of the zero energy bound state is also mentioned.