Oscillating spin-orbit interaction as a source of spin-polarized wave packets in two-terminal nanoscale devices

TL;DR

This paper demonstrates that oscillating Rashba spin-orbit interaction in nanoscale devices can generate spin-polarized wave packets from unpolarized inputs, with analytical solutions revealing Floquet quasi-energies affecting transmitted and reflected waves.

Contribution

It provides an analytical solution showing how time-dependent spin-orbit interaction creates spin polarization and density fluctuations in nanoscale devices.

Findings

Oscillating SOI induces spin-polarized wave packets.

Spin polarization varies in space and time even outside SOI regions.

Floquet quasi-energies influence the energy spectrum of waves.

Abstract

Ballistic transport through nanoscale devices with time-dependent Rashba-type spin-orbit interaction (SOI) can lead to spin-polarized wave packets that appear even for completely unpolarized input. The SOI that oscillates in a finite domain generates density and spin polarization fluctuations that leave the region as propagating waves. Particularly, spin polarization has space and time dependence even in regions without SOI. Our results are based on an analytic solution of the time-dependent Schr\"odinger equation. The relevant Floquet quasi-energies that are obtained appear in the energy spectrum of both the transmitted and reflected waves.