Enhanced Tunnel Spin Injection into Graphene using Chemical Vapor Deposited Hexagonal Boron Nitride

TL;DR

This paper demonstrates enhanced spin injection and transport in graphene using chemical vapor deposited h-BN as a tunnel barrier, achieving significant improvements in spin signal and lifetime for potential spintronic applications.

Contribution

It introduces the use of CVD-grown h-BN as an effective tunnel barrier for spin injection into graphene, showing improved spin transport properties.

Findings

Spin signal amplitude and lifetime increased by an order of magnitude.

Spin transport and precession observed over micrometer distances.

CVD h-BN provides a reliable tunnel barrier for spin injection.

Abstract

The van der Waals heterostructures of two-dimensional (2D) atomic crystals constitute a new paradigm in nanoscience. Hybrid devices of graphene with insulating 2D hexagonal boron nitride (h-BN) have emerged as promising nanoelectronic architectures through demonstrations of ultrahigh electron motilities and charge-based tunnel transistors. Here, we expand the functional horizon of such 2D materials demonstrating the quantum tunneling of spin-polarized electrons through atomic planes of CVD grown h-BN. We report excellent tunneling behavior of h-BN layers together with tunnel spin injection and transport in graphene using ferromagnet/h-BN contacts. Employing h-BN tunnel contacts, we observe enhancements in both spin signal amplitude and lifetime by an order of magnitude. We demonstrate spin transport and precession over micrometer-scale distances with spin lifetime up to 0.46 nanosecond. Our results and complementary magnetoresistance calculations illustrate that CVD h-BN tunnel barrier provides a reliable, reproducible and alternative approach to address the conductivity mismatch problem for spin injection into graphene.