Spin filtering in nanowire directional coupler

TL;DR

This paper presents a theoretical study of spin filtering in a nanowire directional coupler, demonstrating how gate-controlled Rashba spin-orbit interaction can modulate spin currents for potential spintronic applications.

Contribution

It introduces a transfer matrix approach to analyze spin transport and shows how gate voltages can control spin polarization in nanowire couplers.

Findings

Gate fields enable control of spin current in the coupler.

Spin polarization can be modulated via Rashba spin-orbit interaction.

Structural factors influence the spin transport behavior.

Abstract

The spin transport characteristics of a nanowire directional electronic coupler have been evaluated theoretically via a transfer matrix approach. The application of a gate field in the region of mixing allows for control of spin current through the different leads of the coupler via the Rashba spin-orbit interaction. The combination of spin-orbit interaction and applied gate voltages on different legs of the coupler give rise to a controllable modulation of the spin polarization. Both structural factors and field strength tuning lead to a rich phenomenology that could be exploited in spintronic devices.