Spin Hall effect at interfaces between HgTe/CdTe quantum wells and metals

TL;DR

This paper reveals a novel boundary spin Hall effect at HgTe/CdTe quantum well and metal interfaces, driven by edge states, enabling all-electric spin injection without bulk inversion asymmetry.

Contribution

It introduces a new type of spin Hall effect occurring at interfaces, independent of bulk properties, and links it to localized edge states for potential spintronic applications.

Findings

Discovery of a pure boundary spin Hall effect at interfaces.

Demonstration of measurement methods for the effect.

Potential for all-electric spin injection into metals.

Abstract

We study the spin-dependent transmission through interfaces between a HgTe/CdTe quantum well (QW) and a metal - both for the normal metal and the superconducting case. Interestingly, we discover a new type of spin Hall effect at these interfaces that happens to exist even in the absence of structure and bulk inversion asymmetry within each subsystem (i.e. the QW and the metal). Thus, this is a pure boundary spin Hall effect which can be directly related to the existence of exponentially localized edge states at the interface. We demonstrate how this effect can be measured and functionalized for an all-electric spin injection into normal metal leads.