Spin-polarized Majorana Bound States inside a Vortex Core in Topological Superconductors

TL;DR

This paper demonstrates that Majorana bound states in topological superconductors with odd-parity pairing are inherently spin-polarized within vortex cores, a universal feature detectable by spin-sensitive experiments.

Contribution

It reveals the universal spin polarization of Majorana bound states in Dirac superconductivity using the massive Dirac BdG equation, contrasting with conventional BdG predictions.

Findings

Majorana bound states are spin-polarized inside vortex cores.

Spin polarization is universal for Dirac superconductivity.

Detectable by spin-sensitive probes like neutron scattering.

Abstract

We reveal that Majorana bound states inside the vortex core in an odd-parity topological superconductivity classified as "pseudo-scalar" type in the gap function are distinctly spin-polarized by solving the massive Dirac Bogoliubov-de Gennes (BdG) equation considering the spin-orbit coupling. This result is universal for "Dirac superconductivity" whose rotational degree of freedom is characterized by the total angular momentum J = S + L and in marked contrast to the spin-degeneracy of the core bound states as the consequence of the conventional BdG equation. The spin-polarized vortex core can be easily detected by spin-sensitive probes such as the neutron scattering and other measurements well above the first critical magnetic field H_{c1}.