Spin-dependent transmission in waveguides with periodically modulated strength of the spin-orbit interaction

TL;DR

This paper investigates how periodically modulating the spin-orbit interaction in waveguides can control electron transmission, demonstrating spin-transistor behavior and providing a formula for transmission analysis.

Contribution

It introduces a model for spin-dependent electron transmission in waveguides with periodic SOI modulation, revealing spin-transistor functionality and deriving a transparent transmission formula.

Findings

Transmission exhibits spin-transistor action as a function of SOI strength.

Transmission shows periodic behavior related to the waveguide structure.

The derived formula explains the observed transmission patterns.

Abstract

The electron transmission $T$ is evaluated through waveguides, in which the strength of the spin-orbit interaction(SOI) $\alpha$ is varied periodically, using the transfer-matrix technique. It is shown that $T$ exhibits a {\it spin-transistor} action, as a function of $\alpha$ or of the length of one of the two subunits of the unit cell, provided only one mode is allowed to propagate in the waveguide. A similar but not periodic behavior occurs as a function of the incident electron energy. A transparent formula for $T$ through one unit is obtained and helps explain its periodic behavior. The structure considered is a good candidate for the establishment of a realistic spin transistor.