Dynamic RKKY interaction between magnetic moments in graphene nanoribbons

TL;DR

This paper explores the dynamic RKKY interaction in graphene nanoribbons, revealing how impurity coupling can be controlled via gate voltage or doping, with implications for spintronic devices.

Contribution

It introduces a detailed analysis of spin excitations and impurity interactions in graphene nanoribbons, highlighting control mechanisms for spin coupling.

Findings

Impurities on vanishing density of states sites are initially invisible to interactions.

Gate voltage or doping can activate impurity interactions.

Coupling can be switched on or off, enabling transistor-like control.

Abstract

Graphene has been identified as a promising material with numerous applications, particularly in spintronics. In this paper we investigate the peculiar features of spin excitations of magnetic units deposited on graphene nanoribbons and how they can couple through a dynamical interaction mediated by spin currents. We examine in detail the spin lifetimes and identify a pattern caused by vanishing density of states sites in pristine ribbons with armchair borders. Impurities located on these sites become practically invisible to the interaction, but can be made accessible by a gate voltage or doping. We also demonstrate that the coupling between impurities can be turned on or off using this characteristic, which may be used to control the transfer of information in transistor-like devices.