Klein Tunneling of Spin Polarized Currents in HgTe Quantum Wells

TL;DR

This paper explores how spin polarized currents behave in HgTe quantum wells, revealing a Klein-like paradox and a method to manipulate spin currents via potential barriers in topological insulators.

Contribution

It demonstrates a novel mechanism for spin inversion and manipulation of spin polarized currents in HgTe quantum wells using modified BHZ model with barriers.

Findings

Attenuated quantum spin Hall effect observed in gaped region

Spin inversion occurs in strong potential regimes

Potential barriers enable control of spin polarized currents

Abstract

We investigate the behavior of spin polarized currents in two-dimensional topological insulators (TI). Stationary solutions inside a HgTe/CdTe quantum well (QW) were obtained by Bernevig-Hughes-Zhang (BHZ) model modified by a electric and magnetic barrier inside a non-completely insulating bulk. An attenuated quantum spin Hall (QSH) effect occurs in the gaped region with an apparent Klein-like paradox. Even more interesting, for strong potential regime, the interaction between the quasiparticles and the barriers allows spin inversion of this electronic states in a distinct channel conduction. Thus, our findings suggest a mechanism to manipulated spin polarized currents in this system.