Structural Reconstruction of the Graphene Monovacancy

Robertson, Alex W.; Montanari, B.; He, Kui; Allen, Christopher S.; Wu, Yimin A.; Harrison, N. M.; Kirkland, Angus I.; Warner, Jamie H.

doi:10.1021/nn401113r

Cited by 141 publications

(158 citation statements)

References 38 publications

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“…Accordingly, the structure around the vacancy is squeezed, but remains symmetric without rebonding of surrounding atoms. This situation is in contrast to the vacancy in graphene, where reconstruction or rebonding of carbon atoms surrounding the vacancy is observed [32][33][34]. The vacancy formation is an endothermic process and the formation energy of the single vacancy in B-Sb is 5.03 eV.…”

Section: -4mentioning

confidence: 87%

Single-layer crystalline phases of antimony: Antimonenes

2015

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The pseudolayered character of 3D bulk crystals of antimony has led us to predict its 2D single-layer crystalline phase named antimonene in a buckled honeycomb structure like silicene. Sb atoms also form an asymmetric washboard structure like black phospherene. Based on an extensive analysis comprising ab initio phonon and finite-temperature molecular dynamics calculations, we show that these two single-layer phases are robust and can remain stable at high temperatures. They are nonmagnetic semiconductors with band gaps ranging from 0.3 eV to 1.5 eV, and are suitable for 2D electronic applications. The washboard antimonene displays strongly directional mechanical properties, which may give rise to a strong influence of strain on the electronic properties. Single-layer antimonene phases form bilayer and trilayer structures with wide interlayer spacings. In multilayers, this spacing is reduced and eventually the structure changes to 3D pseudolayered bulk crystals. The zigzag and armchair nanoribbons of the antimonene phases have fundamental band gaps derived from reconstructed edge states and display a diversity of magnetic and electronic properties depending on their width and edge geometry. Their band gaps are tunable with the widths of the nanoribbons. When grown on substrates, such as germanene or Ge(111), the buckled antimonene attains a significant influence of substrates.

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Section: -4mentioning

confidence: 87%

Single-layer crystalline phases of antimony: Antimonenes

2015

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“…Recent advances in monochromation of the electron source have enabled AC-TEM with B80 pm spatial resolution at the low accelerating voltage of 80 kV (refs 26,31). We recently demonstrated how this leads to the ability to fully resolve individual atoms in graphene, permitting the precise measurement of C-C bond changes within 5-7-membered ring dislocations and monovacancies 32,33 .…”

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confidence: 99%

Hydrogen-free graphene edges

Lee

Robertson

et al. 2014

Nat Commun

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Graphene edges and their functionalization influence the electronic and magnetic properties of graphene nanoribbons. Theoretical calculations predict saturating graphene edges with hydrogen lower its energy and form a more stable structure. Despite the importance, experimental investigations of whether graphene edges are always hydrogen-terminated are limited. Here we study graphene edges produced by sputtering in vacuum and direct measurements of the C-C bond lengths at the edge show B86% contraction relative to the bulk. Density functional theory reveals the contraction is attributed to the formation of a triple bond and the absence of hydrogen functionalization. Time-dependent images reveal temporary attachment of a single atom to the arm-chair C-C bond in a triangular configuration, causing expansion of the bond length, which then returns back to the contracted value once the extra atom moves on and the arm-chair edge is returned. Our results provide confirmation that non-functionalized graphene edges can exist in vacuum.

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“…Upon formation, the vacancy undergoes a spontaneous Jahn-Teller distortion [39] in which a pairwise reconstruction occurs, weakly binding two of the undercoordinated atoms, leaving one dangling bond [40,41]. This asymmetric reconstruction can rotate to the other two equivalent orientations via a small (∼0.1 eV) barrier [40].…”

Section: Resultsmentioning

confidence: 99%

Interlayer vacancy diffusion and coalescence in graphite

et al. 2014

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Due to the layered nature of graphite, the migration and interaction of point defects in the graphite crystal structure are highly anisotropic, and it is usually assumed that individual mobile lattice vacancies are confined to diffuse on a single plane. We present the results of ab initio calculations based on density functional theory which demonstrate that vacancies can, in fact, move between adjacent planes when they interact with one another via relatively low energy pathways, often with barriers of less than 1 eV. These interlayer transition mechanisms can significantly alter both the kinetics of point-defect aggregation and coalescence and also the resultant morphologies of multivacancy complexes that form as a result of migrating vacancies interacting.

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Structural Reconstruction of the Graphene Monovacancy

Cited by 141 publications

References 38 publications

Single-layer crystalline phases of antimony: Antimonenes

Single-layer crystalline phases of antimony: Antimonenes

Hydrogen-free graphene edges

Interlayer vacancy diffusion and coalescence in graphite

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