Mesoscopic Stern-Gerlach spin filter by nonuniform spin-orbit interaction

TL;DR

This paper proposes a theoretical method for achieving nearly 100% spin polarization in a 2D electron system using nonuniform spin-orbit interactions, enabling spin filtering without external magnetic fields or ferromagnetic contacts.

Contribution

It introduces a novel mesoscopic spin filter based on nonuniform SOI, demonstrating high polarization efficiency and robustness against disorder.

Findings

Almost 100% spin polarization achievable

Polarization persists despite randomness

No external magnetic fields or ferromagnetic contacts needed

Abstract

A novel spin filtering in two-dimensional electron system with nonuniform spin-orbit interactions (SOI) is theoretically studied. The strength of SOI is modulated perpendicular to the charge current. A spatial gradient of effective magnetic field due to the nonuniform SOI causes the Stern-Gerlach type spin separation. The direction of the polarization is perpendicular to the current and parallel to the spatial gradient. Almost 100 % spin polarization can be realized even without applying any external magnetic fields and without attaching ferromagnetic contacts. The spin polarization persists even in the presence of randomness.