Multiscale magnetic study of Ni(111) and graphene on Ni(111)

Dzemiantsova, L. V.; Karolak, M.; Lofink, Fabian; Kubetzka, André; Sachs, B.; Bergmann, Kirsten; Hankemeier, S.; Wehling, T. O.; Frömter, Robert; Oepen, H. P.; Lichtenstein, A. I.; Wiesendanger, R.

doi:10.1103/physrevb.84.205431

Cited by 54 publications

(58 citation statements)

References 40 publications

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“…The total induced spin moment in graphene is very small (≈0.01μ B per unit cell of graphene), and it is interesting to note that it is oriented antiparallel to the Co-ML moment. Note that similar spin magnetic moments at the C atoms are reported for graphene/Ni(111) [43]. Let us compare our data with previously reported graphene/Co/Ir(111) calculations by Decker et al [23].…”

Section: Electronic Structure Calculationssupporting

confidence: 89%

Electronic structure and magnetic properties of cobalt intercalated in graphene on Ir(111)

et al. 2014

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Using a combination of photoemission and x-ray magnetic circular dichroism (XMCD), we characterize the growth and the electronic as well as magnetic structure of cobalt layers intercalated in between graphene and Ir(111). We demonstrate that magnetic ordering exists beyond one monolayer intercalation, and determine the Co orbital and spin magnetic moments. XMCD from the carbon edge shows an induced magnetic moment in the graphene layer, oriented antiparallel to that of cobalt. The XMCD experimental data are discussed in comparison to our results of first-principles electronic structure calculations. It is shown that good agreement between theory and experiment for the Co magnetic moments can be achieved when the local-spin-density approximation plus the Hubbard U (LSDA + U ) is used.

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Section: Electronic Structure Calculationssupporting

confidence: 89%

Electronic structure and magnetic properties of cobalt intercalated in graphene on Ir(111)

et al. 2014

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“…In both cases, the CoCp 2 molecule attains a nominal S=1/2 spin. The small lattice mismatch (1.2%) of graphene and Ni(111) lattice constant results in pseudomorphic growth and the flat conformation of the graphene layer [25]. DFT calculations have shown that the bonding between graphene and the Ni(111) surface is primarily due to van der Waals (vdW) interactions [26], with a binding distance of ∼2.1Å, in good agreement with experiments [27].…”

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confidence: 66%

Graphene-mediated exchange coupling between a molecular spin and magnetic substrates

et al. 2013

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Using first-principles calculations we demonstrate sizable exchange coupling between a magnetic molecule and a magnetic substrate via a graphene layer. As a model system we consider cobaltocene (CoCp2) adsorbed on graphene deposited on Ni(111). We find that the magnetic coupling between the molecule and the substrate is antiferromagnetic and varies considerably depending on the molecule structure, the adsorption geometry, and the stacking of graphene on Ni(111). We show how this coupling can be tuned by intercalating a magnetic monolayer, e.g. Fe or Co, between graphene and Ni(111). We identify the leading mechanism responsible for the coupling to be the spatial and energy matching of the frontier orbitals of CoCp2 and graphene close to the Fermi level, and we demonstrate the role of graphene as an electronic decoupling layer, yet allowing spin communication between molecule and substrate.PACS numbers: 71.15. Mb, 75.50.Xx, 81.05.ue The emerging field of organic spintronics capitalizes on the novel functionalities achieved when organic molecules are adsorbed on magnetic substrates. The ability to manipulate and tune these functionalities is an important goal. Several problems remain however, before such systems can be incorporated into new technological devices. One in particular is the capability to adsorb molecules on surfaces without any detrimental effects being caused to either the structural or magnetic properties of the molecule. For this reason it is vital to choose molecules with maximum structural robustness upon adsorption [1][2][3]. To this end, the phthalocyanine and porphyrin families are popular choices due to their planar geometry [4][5][6][7][8][9]. However, in some cases, the strong interaction between the metal ion of such flat molecules and the substrate can modify its electronic states and even quench its magnetic moment [10].The use of non-planer molecules, such as metallocenes, can minimize this effect. Metallocenes are composed of a 3d transition-metal ion sandwiched between two cyclopentadienyls (Cp). Depending on the metal ion species, both non-magnetic and paramagnetic behavior can be found [11]. The spin of the metal ion is shielded from the surface by the cage formed by the two Cp rings, reducing the possibility that it will be modified substantially after adsorption. Unfortunately, the deposition of metallocenes on metallic surfaces is a difficult process [12] and, in some cases, complete dissociation of the molecule occurs [13,14].The intercalation of a graphene spacer layer between the reactive surface and the metallocene can reduce the possibility of molecular dissociation during deposition. Additionally, evidence of charge transfer at moleculegraphene-Ni(111) interfaces [15,16] and the theoretical prediction of large charge transfer from cobaltocene (CoCp 2 ) to graphene [17] would suggest that a magnetic coupling between cobaltocene and the Ni(111) surface through the graphene layer is still achievable.In this Letter, we predict, by first principles electronic structure metho...

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“…24,31,32 In the STM image of a (1 Â 1) domain there is a notable asymmetry between the two different sublattices due to influence of the Ni(111) surface atoms. Simulations of the graphene/Ni(111) STM images 24,33 demonstrate that the sublattice H, which is located above the hollow sites of the Ni(111) surface (see Figure 3b), must appear higher than the sublattice T, located above the Ni atoms. This allows us to determine the positions of the topmost Ni atoms in the STM images (see blue circles in Figure 3a).…”

Section: Resultsmentioning

confidence: 99%

Epitaxial B-Graphene: Large-Scale Growth and Atomic Structure

et al. 2015

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Embedding foreign atoms or molecules in graphene has become the key approach in its functionalization and is intensively used for tuning its structural and electronic properties.Here, we present an efficient method based on chemical vapor deposition for large scale growth of boron-doped graphene (B-graphene) on Ni(111) and Co(0001) substrates using carborane molecules as the precursor. It is shown that up to 19 at. % of boron can be embedded in the graphene matrix and that a planar CÀB sp 2 network is formed. It is resistant to air exposure and widely retains the electronic structure of graphene on metals. The large-scale and local structure of this material has been explored depending on boron content and substrate. By resolving individual impurities with scanning tunneling microscopy we have demonstrated the possibility for preferential substitution of carbon with boron in one of the graphene sublattices (unbalanced sublattice doping) at low doping level on the Ni(111) substrate. At high boron content the honeycomb lattice of B-graphene is strongly distorted, and therefore, it demonstrates no unballanced sublattice doping.

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Multiscale magnetic study of Ni(111) and graphene on Ni(111)

Cited by 54 publications

References 40 publications

Electronic structure and magnetic properties of cobalt intercalated in graphene on Ir(111)

Electronic structure and magnetic properties of cobalt intercalated in graphene on Ir(111)

Graphene-mediated exchange coupling between a molecular spin and magnetic substrates

Epitaxial B-Graphene: Large-Scale Growth and Atomic Structure

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