Oxygen Intercalation under Graphene on Ir(111): Energetics, Kinetics, and the Role of Graphene Edges

Grånäs, Elin; Knudsen, Jan; Schröder, Ulrike A.; Gerber, Timm; Busse, Carsten; Arman, Mohammad A.; Schulte, Karina; Andersen, Jesper N; Michely, Thomas

doi:10.1021/nn303548z

Cited by 178 publications

(215 citation statements)

References 34 publications

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“…In these hybrid devices the N areas can be obtained by decoupling locally the graphene from the substrate in a controlled way. Among other methods, this could be achieved by intercalation [34][35][36].…”

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confidence: 99%

Induced Superconductivity in Graphene Grown on Rhenium

et al. 2013

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We report a new way to strongly couple graphene to a superconductor. The graphene monolayer has been grown directly on top of a superconducting Re(0001) thin film and characterized by scanning tunneling microscopy and spectroscopy. We observed a moiré pattern due to the mismatch between Re and graphene lattice parameters, that we have simulated with ab initio calculations. The density of states around the Fermi energy appears to be position dependent on this moiré pattern. Tunneling spectroscopy performed at 50 mK shows that the superconducting behavior of graphene on Re is well described by the Bardeen-Cooper-Schrieffer theory and stands for a very good interface between the graphene and its metallic substrate.PACS numbers: 74.55.+v, 73.22.Pr, 71.15.Mb Since its discovery in 2004, graphene has attracted a lot of attention because of its unique electronic properties [1]. In this atomically thin sheet of carbon atoms arranged in a honeycomb lattice, electrons and holes obey to a linear dispersion law and can be described as massless Dirac fermions with a Fermi level coinciding with the Dirac point. This unique situation in condensed matter physics is signaled by an anomalous quantum Hall effect [2].The relativistic quantum description of graphene has also important consequences in the physics of superconductivity [3]. Although bare graphene is not itself superconducting, it is predicted to acquire superconducting properties when doped with alkaline metal adatoms [4,5]. In this situation the Cooper pairing mechanism is either unconventional, with graphene electrons coupling to the metal plasmons, or conventional with electron-phonon coupling between the charge carriers and the different vibrational modes of the carbon and the metal arrays. Another way to induce superconductivity in graphene is to connect it to a superconductor. In this case, the Cooper pairs are only created in the superconducting material. This proximity effect is governed by the Andreev process which converts electrons and holes of a normal metal into each other, allowing the injection of a Cooper pair into the superconductor. A new situation appears in undoped graphene where the hole of the Andreev process is not retroreflected anymore but undergoes a specular Andreev reflection [3,6]. Despite an increasing theoretical activity focusing on the superconductivity in graphene and more generally in Dirac electronic systems [7], on the experimental side, whereas a tunable Josephson supercurrent has been observed in graphene soon after its discovery [8], the superconducting proximity effect in graphene remains very challenging [9][10][11]. One reason is the difficulty to prepare a highly transparent interface between graphene and a superconducting metal [10]. Indeed, while the classical transport experiments are dependent on the transparency T of the interface, the proximity effect ruled by the Andreev reflection is T 2 dependent. In this work we demonstrate a new efficient way to induce superconductivity into graphene by directly growing it onto ...

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confidence: 99%

Induced Superconductivity in Graphene Grown on Rhenium

et al. 2013

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“…It consists of the preparation of graphene on metallic or semiconducting layers via standard chemical vapour deposition (CVD) technique or intercalation under graphene, followed by the oxidation of the underlying metal or semiconductor at relatively high pressure of oxygen. This procedure was used in several recent works, where nearly free-standing graphene on bulk or surface oxide layers was prepared [16][17][18][19][20][21].…”

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confidence: 99%

Decoupling of graphene from Ni(111) via formation of an interfacial NiO layer

Dedkov

Klesse

Becker

et al. 2017

Carbon

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The combination of the surface science techniques (STM, XPS, ARPES) and density-functional theory calculations was used to study the decoupling of graphene from Ni(111) by oxygen intercalation. The formation of the antiferromagnetic (AFM) NiO layer at the interface between graphene and ferromagnetic (FM) Ni is found, where graphene protects the underlying AFM/FM sandwich system. It is found that graphene is fully decoupled in this system and strongly p-doped via charge transfer with a position of the Dirac point of (0.69 ± 0.02) eV above the Fermi level. Our theoretical analysis confirms all experimental findings, addressing also the interface properties between graphene and AFM NiO.

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“…Surface science studies on the well-defined graphene/metal surfaces have shown that gaseous molecules such as CO, O 2 , and H 2 O can be readily intercalated under the graphene overlayers (21-27). Defects in graphene including island edges (22,23,(28)(29)(30), domain boundaries (26,31,32), and wrinkles (33) provide channels for molecule diffusion into the graphene/metal interfaces. These new results raise the intriguing possibility that the space between graphene overlayers and metal substrates can act as a 2D container for reactions.…”

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confidence: 99%

Graphene cover-promoted metal-catalyzed reactions

Yao

Zhang

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

186

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Graphitic overlayers on metals have commonly been considered as inhibitors for surface reactions due to their chemical inertness and physical blockage of surface active sites. In this work, however, we find that surface reactions, for instance, CO adsorption/desorption and CO oxidation, can take place on Pt(111) surface covered by monolayer graphene sheets. Surface science measurements combined with density functional calculations show that the graphene overlayer weakens the strong interaction between CO and Pt and, consequently, facilitates the CO oxidation with lower apparent activation energy. These results suggest that interfaces between graphitic overlayers and metal surfaces act as 2D confined nanoreactors, in which catalytic reactions are promoted. The finding contrasts with the conventional knowledge that graphitic carbon poisons a catalyst surface but opens up an avenue to enhance catalytic performance through coating of metal catalysts with controlled graphitic covers.arbonaceous deposits such as carbidic carbon and graphitic carbon often form on transition metal (TM) surfaces in catalytic processes involving carbon-containing reactants (1). It has been shown that carbidic species can be involved in some hydrogenation reactions, which are attributed to the observed high reaction activity (2-5). In contrast, graphitic carbon deposited on TM is conventionally considered as catalyst poison due to its chemical inertness and physical blockage of surface active sites (6-8). It has been generally assumed that formation of graphitic carbon on metal catalysts should be avoided before and during catalytic reactions (9, 10). Nevertheless, for decades, extensive research efforts have been made to use surface carbon layers formed on TMs and to understand their role in catalytic reactions (11)(12)(13)(14), which, however, have been impeded by complexity of the ill-defined carbon structures. Graphene, as a simple form of graphitic deposit, has been grown on many late TM surfaces via catalytic cracking of carbon-containing gases (15)(16)(17)(18)(19)(20). Surface science studies on the well-defined graphene/metal surfaces have shown that gaseous molecules such as CO, O 2 , and H 2 O can be readily intercalated under the graphene overlayers (21-27). Defects in graphene including island edges (22,23,(28)(29)(30), domain boundaries (26,31,32), and wrinkles (33) provide channels for molecule diffusion into the graphene/metal interfaces. These new results raise the intriguing possibility that the space between graphene overlayers and metal substrates can act as a 2D container for reactions. The distance between the graphene overlayers and the metal surfaces typically falls in the subnanometer range (19,20), and molecules trapped inside interact directly with both the graphene cover and the metal substrate. Catalytic reactions, if occurring, are strongly confined in the 2D space, and extraordinary catalytic performance may be expected due to the confinement effect. In the present work, graphene/Pt(111) [Gr/Pt(111)] was used ...

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Oxygen Intercalation under Graphene on Ir(111): Energetics, Kinetics, and the Role of Graphene Edges

Cited by 178 publications

References 34 publications

Induced Superconductivity in Graphene Grown on Rhenium

Induced Superconductivity in Graphene Grown on Rhenium

Decoupling of graphene from Ni(111) via formation of an interfacial NiO layer

Graphene cover-promoted metal-catalyzed reactions

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