Ballistic spin filtering across the ferromagnetic-semiconductor interface

TL;DR

This paper presents a theoretical model for ballistic spin filtering at ferromagnetic-semiconductor interfaces, aiming to improve spin detection by analyzing spin-polarized tunneling in superlattice structures.

Contribution

It develops a new physical model for spin filtering across ferromagnetic-semiconductor interfaces, facilitating experimental measurement of spin-polarized tunneling conductance asymmetry.

Findings

Model enables straightforward extraction of spin-polarized tunneling asymmetry.

Guides future spin detection techniques with enhanced performance.

Provides theoretical foundation for spin filtering in superlattice structures.

Abstract

The ballistic spin-filter effect from a ferromagnetic metal into a semiconductor has theoretically been studied with an intention of detecting the spin polarizability of density of states in FM layer at a higher energy level. The physical model for the ballistic spin filtering across the interface between ferromagnetic metals and semiconductor superlattice is developed by exciting the spin polarized electrons into n-type AlAs/GaAs superlattice layer at a much higher energy level and then ballistically tunneling through the barrier into the ferromagnetic film. Since both the helicity-modulated and static photocurrent responses are experimentally measurable quantities, the physical quantity of interest, the relative asymmetry of spin-polarized tunneling conductance, could be extracted experimentally in a more straightforward way, as compared with previous models. The present physical model serves guidance for studying spin detection with advanced performance in the future.