Metals on Graphene: Interactions, Growth Morphology, and Thermal Stability

Liu, Xiaojie; Wang, Cai‐Zhuang; Hupalo, M.; Lin, Hai‐Qing; Ho, Kai‐Ming; Tringides, Michael C.

doi:10.3390/cryst3010079

Cited by 151 publications

(169 citation statements)

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“…The bonding-induced change in electron density is mainly localized on the carbon atoms closest to the metal adatom [54,55]. Among the physisorbed metals, Au exhibits net electron transfer from the substrate to the metal adatom, in keeping with the fact that Au is a very electronegative metal [58,59].…”

Section: Bonding Of a Metal Adatom To The Basal Planementioning

confidence: 92%

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Transition metals on the (0 0 0 1) surface of graphite: Fundamental aspects of adsorption, diffusion, and morphology

Appy

Lei

Wang

et al. 2014

Progress in Surface Science

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In this article, we review basic information about the interaction of transition metal atoms with the (0001) surface of graphite, especially fundamental phenomena related to growth. Those phenomena involve adatomsurface bonding, diffusion, morphology of metal clusters, interactions with steps and sputter-induced defects, condensation, and desorption. General traits emerge which have not been summarized previously. Some of these features are rather surprising when compared with metal-on-metal adsorption and growth. Opportunities for future work are pointed out. Chemistry | Materials Science and Engineering | PhysicsComments NOTICE: This is the author's version of a work that was accepted for publication in Progress in Surface Science. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publications. A definitive version was subsequently published in Progress in Surface Science, 89 (2014), doi: 10.1016/j.progsurf.2014.08.001. AuthorsDavid Victor Appy, Huaping Lei, Cai-Zhuang Wang, Michael C. Tringides, Da-Jiang Liu, James W. Evans, and Patricia A. Thiel This article is available at Iowa State University Digital Repository: http://lib.dr.iastate.edu/chem_pubs/99 1 NOTICE: This is the author's version of a work that was accepted for publication in Progress in Surface Science. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publications. A definitive version was subsequently published in Progress in Surface Science, 89 (2014) Abstract.In this article, we review basic information about the interaction of transition metal atoms with the (0001) surface of graphite, especially fundamental phenomena related to growth. Those phenomena involve adatom-surface bonding, diffusion, morphology of metal clusters, interactions with steps and sputter-induced defects, condensation, and desorption. General traits emerge which have not been summarized previously. Some of these features are rather surprising when compared with metal-onmetal adsorption and growth. Opportunities for future work are pointed out. 1.Introduction.Graphite is an intriguing support for metals because of its inertness in aggressive environments, as well as its low cost and high abundance. A major application for graphite-supported metals is lithium ion batteries [1,2]. In fact, the demand for these batteries is expanding so quickly that it currently drives the international market in graphite [1]. An important application on the horizon is biofuel conversion, where graphite (or other carbon-based materials) may provide robust supports for catalysts in aqueous media [3].Adsorption of transition metals and noble metals on graphite has been studi...

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Section: Bonding Of a Metal Adatom To The Basal Planementioning

confidence: 92%

“…(1), we briefly review its trends among 3d metals [54,55]. First consider the variation along a single row.…”

Section: Bonding Of a Metal Adatom To The Basal Planementioning

confidence: 99%

Transition metals on the (0 0 0 1) surface of graphite: Fundamental aspects of adsorption, diffusion, and morphology

Appy

Lei

Wang

et al. 2014

Progress in Surface Science

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“…This type of combination is important for major energy-related technologies involving catalysis [1] and electrochemistry [2,3], and also for the exploitation of carbon-based solids in magnetic or electronic devices [4,5]. There have been many studies of model systems, especially studies of transition metals on graphite.…”

Section: Introductionmentioning

confidence: 99%

Determining whether metals nucleate homogeneously on graphite: A case study with copper

et al. 2014

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Abstract.We observe that Cu clusters grow on surface terraces of graphite as a result of physical vapor deposition in ultrahigh vacuum. We show that the observation is incompatible with a variety of models incorporating homogeneous nucleation and highlevel calculations of atomic-scale energetics. An alternative explanation, ion-mediated heterogeneous nucleation, is proposed and validated, both with theory and experiment. This serves as a case study in identifying when and whether the simple, common observation of metal clusters on carbon-rich surfaces can be interpreted in terms of homogeneous nucleation. We describe a general approach for making system-specific and laboratory-specific predictions. Introduction.The conditions under which solids grow on solid surfaces determine the structure, properties, and distribution of the grown material. One of the simplest-and most informative-growth scenarios is that in which single atoms impinge on a solid surface, then diffuse randomly and aggregate into clusters. This situation is informative because there can be a direct relationship between clusters' characteristics (e.g. number density and size distribution) and the energetics of individual processes (e.g. diffusion of atoms and cluster nucleation). However, there is a basic condition for applying this relationship: Nucleation and growth must occur on homogeneous (defect-free) surface regions. Usually, the experimental observation of clusters on low-index surface terraces is taken to be a strong indication that this condition is met.A timely example of solid-on-solid growth is that of metals on carbon-based solids, especially on graphene and graphite. This type of combination is important for major energy-related technologies involving catalysis [1] and electrochemistry [2,3], and also for the exploitation of carbon-based solids in magnetic or electronic devices [4,5]. There have been many studies of model systems, especially studies of transition metals on graphite. [6] In these studies, it has been very common to observe clusters of metals on the (0001) terraces of graphite [6]. However, only rarely have the clusters' characteristics been analyzed in relation to the mechanism or energetics of homogeneous nucleation and

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“…1,2 Realizing highly ordered and monodispersed magnetic structures stands as one of the key challenges for increasing the bit density of magnetic storage devices. The ultimate limit of a single atom per bit guarantees the highest storage density and minimal dipolar coupling among the bits.…”

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confidence: 99%

Superlattice of Single Atom Magnets on Graphene

et al. 2016

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Regular arrays of single atoms with stable magnetization represent the ultimate limit of ultrahigh density storage media. Here we report a self-assembled superlattice of individual and noninteracting Dy atoms on graphene grown on Ir(111), with magnetic hysteresis up to 5.6 T and spin lifetime of 1000 s at 2.5 K. The observed magnetic stability is a consequence of the intrinsic low electron and phonon densities of graphene and the 6-fold symmetry of the adsorption site. Our array of single atom magnets has a density of 115 Tbit/inch 2 , defined by the periodicity of the graphene moirépattern. KEYWORDS: Single atom magnets, self-assembly, superlattice, rare earth atoms, graphene, XMCD T he fabrication of ordered structures at the nanoscale is a crucial step toward information storage at ultimate length scales.1,2 Realizing highly ordered and monodispersed magnetic structures stands as one of the key challenges for increasing the bit density of magnetic storage devices. The ultimate limit of a single atom per bit guarantees the highest storage density and minimal dipolar coupling among the bits. Single-ion molecular magnets, 3 as well as metal−organic networks, 4 allow the selfassembly of single magnetic atoms in ultradense arrays. The molecular cage defines the spacing between the magnetic cores and can protect them from contamination. However, the coupling with electrons and vibrational modes of the surrounding ligands limits the magnetic stability of the magnetic core presently to temperatures below 20 K in bulk 5 and 8 K for surface supported molecules. 6 The absence of the organic ligand, i.e., having individual atoms adsorbed on the surface, may result in a reduced interaction with the environment and greater magnetic stability. Intense research on the magnetism of single atoms 7−12 has culminated in the achievement of magnetic remanence in Ho atoms randomly adsorbed onto MgO, with magnetic stability up to 40 K. 13 Reading and writing of these atoms has recently been demonstrated.14 Nevertheless, so far the realization of an ensemble of single atoms combining long magnetic lifetimes with spatial order has remained elusive and stands as the next milestone. Here we exploit the selective adsorption of Dy atoms in the periodic moirépattern formed by graphene on lattice mismatched Ir(111) 15 to create a superlattice of single atom magnets with a mean distance of 2.5 nm and negligible mutual magnetic interactions.Ensembles of individual Dy atoms on graphene on Ir(111) are obtained by deposition with an e-beam evaporator ( Figure 1a, middle). The spatial arrangement of these atoms on the graphene moirépattern can be controlled by the sample temperature during deposition, T dep . Deposition below 10 K yields statistical growth with a random distribution of Dy atoms, as demonstrated by scanning tunneling microscopy (STM) in Figure 1a, left. At 40 K, surface diffusion of Dy is activated and, therefore, the atoms can reach the most favorable adsorption site in the moiréunit cell, namely, where the C-...

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Metals on Graphene: Interactions, Growth Morphology, and Thermal Stability

Cited by 151 publications

References 117 publications

Transition metals on the (0 0 0 1) surface of graphite: Fundamental aspects of adsorption, diffusion, and morphology

Transition metals on the (0 0 0 1) surface of graphite: Fundamental aspects of adsorption, diffusion, and morphology

Determining whether metals nucleate homogeneously on graphite: A case study with copper

Superlattice of Single Atom Magnets on Graphene

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