Selective Equal-Spin Andreev Reflections Induced by Majorana Fermions

TL;DR

This paper demonstrates that Majorana fermions induce selective equal-spin Andreev reflections, enabling spin-polarized currents and providing a method to detect Majorana fermions in topological superconductors.

Contribution

It reveals a novel spin-selective Andreev reflection process induced by Majorana fermions, with potential applications in spintronics and Majorana detection.

Findings

Majorana fermions induce SESARs with specific spin polarization

SESARs generate fully spin-polarized charge currents

SESARs can serve as a detection method for Majorana fermions

Abstract

In this work, we find that Majorana fermions induce selective equal spin Andreev reflections (SESARs), in which incoming electrons with certain spin polarization in the lead are reflected as counter propagating holes with the same spin. The spin polarization direction of the electrons of this Andreev reflected channel is selected by the Majorana fermions. Moreover, electrons with opposite spin polarization are always reflected as electrons with unchanged spin. As a result, the charge current in the lead is spin-polarized. Therefore, a topological superconductor which supports Majorana fermions can be used as a novel device to create fully spin-polarized currents in paramagnetic leads. We point out that SESARs can also be used to detect Majorana fermions in topological superconductors.