Dynamically-generated pure spin current in single-layer graphene

TL;DR

This paper demonstrates a novel method for generating pure spin currents in single-layer graphene using dynamical spin injection, overcoming the conductance mismatch problem and achieving room-temperature spin transport.

Contribution

The study introduces a new dynamical spin injection technique that enables pure spin current generation in graphene without the need for high-quality tunnel barriers.

Findings

Successful room-temperature spin current generation in graphene.

Estimated spin coherence length of 1.36 μm.

Spin relaxation governed by Elliot-Yafet mechanism.

Abstract

The conductance mismatch problem limits the spin-injection efficiency significantly, and spin-injection into graphene has been usually requiring high-quality tunnel barriers to circumvent the conductance mismatch. We introduce a novel approach, which enables generation of a pure spin current into single-layer graphene (SLG) free from electrical conductance mismatch by using dynamical spin injection. Experimental demonstration of spin-pumping-induced spin current generation and spin transport in SLG at room temperature was successfully achieved and the spin coherence was estimated to be 1.36 {\mu}m by using a conventional theoretical model based on Landau-Lifshitz-Gilbert equation. The spin coherence is proportional to the quality of SLG, which indicates that spin relaxation in SLG is governed by the Elliot-Yafet mechanism as was reported.