Adsorption of Co and Ni on Graphene with a Double Hexagonal Symmetry: Electronic and Magnetic Properties

Abstract

Inspired by Lie symmetries, we study the electronic and magnetic properties of cobalt (Co) and nickel (Ni) adatom adsorption on the graphene material using density functional theory calculations. The system we consider here consists of a static single layer of graphene interacting with transition-metal (TM) atoms. This system shows a nice geometrical shape having a double hexagonal structure appearing in the G 2 Lie algebra. This structure is associated with 25% concentration corresponding to a coverage of 0.666 monolayers placed at H sites. This new symmetry forces the derived Co material to behave like a ferromagnetic metal with a strong spin polarization. However, the derived Ni material remains a nonmagnetic metal. For the Co case, we show that the magnetic mechanism responsible for such behavior is the interaction between the Co atoms. In fact, there are two interaction types. The first one is associated with the direct interaction between the Co atoms, while the second one corresponds to the indirect interaction via the carbon atoms. Using Monte Carlo simulation, the Curie temperature for the Co material is estimated to be around 438 K. This value could be explored in nanomagnetic applications.

Fundamental Properties of Transition‐Metals‐Adsorbed Graphene

“…The fundamental properties of transition‐metal‐adsorbed graphene systems are fully explored under the various adatoms, concentrations and distributions. Based on the completely calculated results, transition metals are preferably adsorbed at the hollow‐site compared to the top‐ and bridge‐sites, which is consistent with previous theoretical predictions . The adatom distribution of transition metals on a graphene surface could be examined by experimental measurement, for which STM is an efficient tool.…”

“…[17][18][19][20] These systems have been reported to exhibit magnetism and other interesting properties that are promising for spintronic devices and batteries. [21][22][23] The aim of our present work is to investigate the transition metal-enriched fundamental properties of monolayer graphene.…”

“…It is worthy noting that the chemisorption of transition metal adatoms to carbon honeycomb lattice creates a fully modified system without damaging the distinctive one-atomthick construction itself. Fe-, [21,24,25] Co-, [25][26][27] and Ni- [22,25,28] doped graphene materials have been successfullyproduced. In general, there exist two available methods for depositing transition metals onto graphene-based materials.…”

Graphene: a self-reducing template for synthesis of graphene–nanoparticles hybrids

“…It has been reported that these metal nanoparticles can be uniformly decorated on graphene surface without forming any carbides [32][33][34] . The graphene-metal hybrids have been found to be highly stable in terms of particle size as a function of reaction time, temperature and reaction between graphene and metal nanoparticles (see supporting information).…”

Mixed Spins in a Nano-system Built on a Dendrimer Structure: Monte Carlo Study

“…Accordingly, the principal hexagonal unit cell has now in all 12 atoms leading to (1×1) and ( √ 3 × √ 3)R30 • superstructures on the two parallel sheets divided by a length distance fixed by the relaxation method. Thanks to the use of WIEN2K code whose basis is on the DFT method [19,20], the properties of the double hexagonal material have been computed or worked out. It is worth noting here that these properties are electronic and magnetic.…”