Influence of subband mixing, due to spin-orbit interaction, on the transmission through periodically modulated waveguides

TL;DR

This paper investigates how spin-orbit interaction-induced subband mixing affects ballistic spin transport in periodically stubbed waveguides, revealing significant changes in transmission patterns and potential for spin transistor applications.

Contribution

It demonstrates the impact of subband mixing on transmission in stubbed waveguides with spin-orbit interaction, highlighting conditions for spin control and transistor-like behavior.

Findings

Transmission exhibits a periodic, nearly square-wave pattern with wide gaps.

Subband mixing causes drastic changes in transmission peaks and dips.

Transmission remains robust against stub asymmetry variations.

Abstract

Ballistic spin transport, through periodically stubbed waveguides, is studied in the presence of a weak spin-orbit interaction (SOI) and the resulting subband mixing. By an appropriate choice of the waveguide length and of the stub parameters injected spin-polarized electrons can be blocked completely and the transmission shows a periodic and nearly square-wave pattern with wide gaps when only one mode is allowed to propagate in the waveguide. Relative to the case when subband mixing is neglected, the transmission changes drastically as a function of the incident electron energy or of the stub height, as it exhibits new peaks or dips, but remains robust as a function of the stubs' degree of asymmetry. Varying the strength of the SOI parameter changes the relative contribution to the total transmission or conductance of the spin-up and spin-down states. The structure considered is a reasonable candidate for establishing a spin transistor.