Dual origin of defect magnetism in graphene and its reversible switching by molecular doping

Abstract

Control of magnetism by applied voltage is desirable for spintronics applications. Finding a suitable material remains an elusive goal, with only a few candidates found so far. Graphene is one of them and attracts interest because of its weak spin-orbit interaction, the ability to control electronic properties by the electric field effect and the possibility to introduce paramagnetic centres such as vacancies and adatoms. Here we show that the magnetism of adatoms in graphene is itinerant and can be controlled by doping, so that magnetic moments are switched on and off. The much-discussed vacancy magnetism is found to have a dual origin, with two approximately equal contributions; one from itinerant magnetism and the other from dangling bonds. Our work suggests that graphene's spin transport can be controlled by the field effect, similar to its electronic and optical properties, and that spin diffusion can be significantly enhanced above a certain carrier density.

Role of direct exchange and Dzyaloshinskii-Moriya interactions in magnetic properties of graphene derivatives: C2F and C2HМазуренко1, Руденко2, Nikolaev3 et al. 2016Phys. Rev. B612460View full textAdd to dashboardCite

“…According to theoretical predictions, sp-electron magnetic semiconductors might also have much higher Curie temperatures than the conventional ones [3,4]. Activities in this direction stimulate synthesis and magnetic measurements of graphene with vacancies and different types of adsorbates [5][6][7][8][9][10][11]. Despite considerable efforts, the available experimental data on magnetism in graphene-based systems is still limited.…”

Interaction between single vacancies in graphene sheet: An ab initio calculation

“…Ideal graphene sheet is nonmagnetic, then to use graphene for spintronic applications the major challenge is to make graphene magnetic. In this sense, the experimental observation of magnetic properties in graphene and related materials [4][5][6][7][8] has drawn huge interest, especially considering the applications of these materials in spintronics, quantum information processing and others.…”

Structural manipulation of the graphene/metal interface with Ar+irradiation

“…[4][5][6] For supported graphene, experimental studies have been carried out for irradiation with 140-eV Ar + on Pt(111) 7 and SiC(0001) 8 surfaces, 30-and 100-keV Ar + on SiO 2 substrate, 9,10 and 5-keV Xe + on Ir(111) surface (at a grazing angle). 11 Ion irradiation has already been demonstrated to tune the electronic and magnetic properties of graphene 9,[12][13][14] and to create single 7 and double vacancies, 8 although no direct correlation between the properties and defect structures has been carried out. Overall, as far as we know, no atomic-level analysis of irradiation-induced structural changes at varying irradiation energies has been reported for supported graphene.…”