A critical analysis of vacancy-induced magnetism in mono and bilayer graphene

Abstract

The observation of intrinsic magnetic order in graphene and graphene-based materials relies on the formation of magnetic moments and a sufficiently strong mutual interaction. Vacancies are arguably considered the primary source of magnetic moments. Here we present an in-depth density functional theory study of the spin-resolved electronic structure of (monoatomic) vacancies in graphene and bilayer graphene. We use two different methodologies: supercell calculations with the SIESTA code and cluster-embedded calculations with the ALACANT package. Our results are conclusive: The vacancy-induced extended $\pi$ magnetic moments, which present long-range interactions and are capable of magnetic ordering, vanish at any experimentally relevant vacancy concentration. This holds for $\sigma$-bond passivated and un-passivated reconstructed vacancies, although, for the un-passivated ones, the disappearance of the $\pi$ magnetic moments is accompanied by a very large magnetic susceptibility. Only for the unlikely case of a full $\sigma$-bond passivation, preventing the reconstruction of the vacancy, a full value of 1${\mu }_B$ for the $\pi$ extended magnetic moment is recovered for both mono and bilayer cases. Our results put on hold claims of vacancy-induced ferromagnetic or antiferromagnetic order in graphene-based systems, while still leaving the door open to $\sigma$-type paramagnetism.

Submitted to Phys. Rev B, 9 pages

References in corpus (17)

• Half-Metallic Graphene Nanoribbons
• Magnetism in Graphene Induced by Single-Atom Defects
• Magnetism in graphene nano-islands
• Self-passivating edge reconstructions of graphene
• Structure, Stability, Edge States and Aromaticity of Graphene Ribbons
• Room-temperature ferromagnetism in graphite driven by 2D networks of point defects
• Disorder Induced Localized States in Graphene
• Vacancy induced magnetism in graphene and graphene ribbons
• Metallic Graphene Nanodisks
• Half-metallic graphene nanodots
• First principles study of magnetism in nanographenes
• A Defective Graphene Phase Predicted to be a Room Temperature Ferromagnetic Semiconductor
• Experimental Evidence for Two-Dimensional Magnetic Order in Proton Bombarded Graphite
• Magnetic moments in the presence of topological defects in graphene
• Magnetism and structure at a vacancy in graphene
• Monovacancy-induced magnetism in graphene bilayers
• Hysteresis loops of the magnetoconductance in graphene devices

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• Point Defects in Twisted Bilayer Graphene: A Density Functional Theory Study
• Vacancy mediated magnetization and healing of a graphene monolayer
• Vacancy-induced tunable Kondo effect in twisted bilayer graphene
• Monovacancy paramagnetism in neutron-irradiated graphite probed by ${}^{13}$C NMR
• Pseudospin-mediated Atomic-scale Vortices and Their Quantum Interferences in Monolayer Graphene
• Magnetic correlation effects by the topological zero mode in a hydrogenated graphene vacancy $V_{111}$