Spin-polarized transport and Andreev reflection in semiconductor/superconductor hybrid structures

TL;DR

This paper investigates how spin-polarized electrons transmit through semiconductor/superconductor structures, revealing that Andreev reflection amplitude effectively measures spin polarization regardless of interface scattering or Fermi velocity mismatch.

Contribution

It demonstrates the robustness of Andreev reflection amplitude as a measure of spin polarization in hybrid structures, considering various interface scattering effects.

Findings

Enhanced junction transparency with increased Fermi velocity mismatch.

Andreev reflection amplitude is independent of interface scattering strengths.

Spin polarization can be accurately gauged via Andreev reflection at the gap energy.

Abstract

We show that spin-polarized electron transmission across semiconductor/superconductor (Sm/S) hybrid structures depends sensitively on the degree of spin polarization as well as the strengths of potential and spin-flip scattering at the interface. We demonstrate that increasing the Fermi velocity mismatch in the Sm and S regions can lead to enhanced junction transparency in the presence of spin polarization. We find that the Andreev reflection amplitude at the superconducting gap energy is a robust measure of the spin polarization magnitude, being independent of the strengths of potential and spin-flip scattering and the Fermi velocity of the superconductor.