Current-induced spin polarization in topological insulator-graphene heterostructures

TL;DR

This paper demonstrates the injection of spin-polarized current from a topological insulator into graphene within a heterostructure, showing potential for all-electric spintronic devices, with detectable signals up to 15 K.

Contribution

It introduces a novel heterostructure combining topological insulators and graphene for spin injection, advancing spintronics technology.

Findings

Spin-polarized current injection from topological insulator into graphene.

Spin switching signal detectable up to ~15 K.

Inverse temperature dependence of the spin signal magnitude.

Abstract

Further development of the field of all-electric spintronics requires the successful integration of spin transport channels with spin injector/generator elements. While with the advent of graphene and related 2D materials high performance spin channel materials are available, the use of nanostructured spin generators remains a major challenge. Especially promising for the latter purpose are 3D topological insulators, whose 2D surface states host massless Dirac fermions with spin-momentum locking. Here, we demonstrate injection of spin-polarized current from a topological insulator into graphene, enabled by its intimate coupling to an ultrathin Bi2Te2Se nanoplatelet within a van der Waals epitaxial heterostructure. The spin switching signal, whose magnitude scales inversely with temperature, is detectable up to ~15 K. Our findings establish topological insulators as prospective future components of spintronic devices wherein spin manipulation is achieved by purely electrical means.