All-Electrical Generation of Spin-Polarized Currents in Quantum Spin Hall Insulators

TL;DR

This paper introduces a purely electrical method to generate and control spin-polarized currents in quantum spin Hall insulators like stanene nanoribbons, avoiding magnetic materials and external fields, with potential spintronics applications.

Contribution

It proposes a novel all-electrical approach to produce spin-polarized currents in QSH insulators using intrinsic spin-orbit coupling and phase tuning, without spin-flip mechanisms.

Findings

Demonstrates control of SPCs via gate voltage in stanene nanoribbons.

Shows robustness of SPC generation against edge imperfections.

Validates method for other QSH insulators like silicene and germanene.

Abstract

The control and generation of spin-polarized currents (SPCs) without magnetic materials and external magnetic field is a big challenge in spintronics and normally requires spin-flip mechanism. In this work, we propose a novel method to control and generate SPCs in stanene nanoribbons in the quantum spin Hall (QSH) insulator regime by all electrical means without spin-flip mechanism. This is achieved with intrinsic spin-orbit coupling in stanene nanoribbons by tuning the relative phase of spin up and down electrons using a gate voltage, which creates a time delay between them thereby producing alternative SPCs driven by ac voltage. The control and generation of SPCs are demonstrated numerically for ac transport in both transient and ac regime. Our results are robust against edge imperfections and generally valid for other QSH insulators such as silicene and germanene, etc. These findings establish a novel route for generating SPCs by purely electrical means and open the door for new applications of semiconductor spintronics.