Pure spin current devices based on ferromagnetic topological insulators

TL;DR

This paper explores heterostructures of topological insulators and ferromagnetic topological insulators, demonstrating their potential for high-fidelity control and conversion of pure spin currents in spintronic devices, possibly operable at room temperature.

Contribution

It introduces novel heterostructure-based spintronic devices capable of creating, switching, and detecting pure spin currents with high efficiency and fidelity.

Findings

Spin current flow can be precisely controlled in heterostructures.

Devices can convert electrical currents into pure spin currents efficiently.

Potential for room-temperature operation due to large bulk gaps.

Abstract

Two-dimensional topological insulators possess two counter propagating edge channels with op- posite spin direction. Recent experimental progress allowed to create ferromagnetic topological insulators realizing a quantum anomalous Hall (QAH) state. In the QAH state one of the two edge channels disappears due to the strong ferromagnetic exchange field. We investigate heterostuctures of topological insulators and ferromagnetic topological insulators by means of numerical transport calculations. We show that spin current flow in such heterostructures can be controlled with high fidelity. Specifically, we propose spintronic devices that are capable of creating, switching and de- tecting pure spin currents using the same technology. In these devices electrical currents are directly converted into spin currents, allowing a high conversion efficiency. Energy independent transport properties in combination with large bulk gaps in some topological insulator materials may allow operation even at room temperature.