Metastable Frenkel Pair Defect in Graphite: Source of Wigner Energy?

Ewels, Christopher P.; Telling, RH; El-Barbary, A. A.; Heggie, M. I.; Briddon, P.R.

doi:10.1103/physrevlett.91.025505

Cited by 143 publications

(121 citation statements)

References 25 publications

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“…It could be interpreted as metastable Frenkel defect, analogously to defects in graphite. 94 The configuration we found does not give rise to double-peak structures in the STS spectra, which confirms that such features cannot be associated with close CA-SV pairs.…”

Section: F Multiple Point Defectssupporting

confidence: 73%

Modifying the electronic structure of semiconducting single-walled carbon nanotubes byAr+ion irradiation

et al. 2009

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Local controllable modification of the electronic structure of carbon nanomaterials is important for the development of carbon-based nanoelectronics. By combining density-functional theory simulations with Arion-irradiation experiments and low-temperature scanning tunneling microscopy and spectroscopy ͑STM/STS͒ characterization of the irradiated samples, we study the changes in the electronic structure of single-walled carbon nanotubes due to the impacts of energetic ions. As nearly all irradiation-induced defects look as nondistinctive hillocklike features in the STM images, we compare the experimentally measured STS spectra to the computed local density of states of the most typical defects with an aim to identify the type of defects and assess their abundance and effects on the local electronic structure. We show that individual irradiationinduced defects can give rise to single and multiple peaks in the band gap of the semiconducting nanotubes and that a similar effect can be achieved when several defects are close to each other. We further study the stability of defects and their evolution during STM measurements. Our results not only shed light on the abundance of the irradiation-induced defects in carbon nanotubes and their signatures in STS spectra but also suggest a way the STM can be used for engineering the local electronic structure of defected carbon nanotubes.

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Section: F Multiple Point Defectssupporting

confidence: 73%

Modifying the electronic structure of semiconducting single-walled carbon nanotubes byAr+ion irradiation

et al. 2009

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“…83 Other defects such as close metastable Frenkel pairs, sometimes referred to as "Wigner defects", exist in bilayer graphene. 25,82 …”

Section: Defect Typesmentioning

confidence: 99%

Structural Defects in Graphene

2010

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Graphene is one of the most promising materials in nanotechnology. The electronic and mechanical properties of graphene samples with high perfection of the atomic lattice are outstanding, but structural defects, which may appear during growth or processing, deteriorate the performance of graphenebased devices. However, deviations from perfection can be useful in some applications, as they make it possible to tailor the local properties of graphene and to achieve new functionalities. In this article, the present knowledge about point and line defects in graphene are reviewed. Particular emphasis is put on the unique ability of graphene to reconstruct its lattice around intrinsic defects, leading to interesting effects and potential applications. Extrinsic defects such as foreign atoms which are of equally high importance for designing graphene-based devices with dedicated properties are also discussed.

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“…The lowest energy state for an isolated interstitial atom in graphite is a structure with C 2 symmetry, known as a spiro-interstitial [44,52,127,140]. A self interstitial can also coexist in very close proximity to a lattice vacancy without mutual annihilation [141]. This is a metastable state, called an intimate Frenkel defect.…”

Section: Displacement Defectsmentioning

confidence: 99%

The contribution made by lattice vacancies to the Wigner effect in radiation-damaged graphite

Latham

Heggie

Alatalo

et al. 2013

J. Phys.: Condens. Matter

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Models for radiation damage in graphite are reviewed and compared, leading to a re-examination of the contribution made by vacancies to annealing processes. A method based on density functional theory, using large supercells with orthorhombic and hexagonal symmetry, is employed to calculate properties and behaviour of lattice vacancies and displacement defects. It is concluded that annihilation of intimate Frenkel defects marks the onset of recovery in electrical resistivity, which occurs when the temperature exceeds about 160 K. Migration of isolated monovacancies is estimated to have an activation energy of E a ≈ 1.1 eV. Coalescence into divacancy defects occurs in several stages, with different barriers at each stage, depending on the path. The formation of pairs ultimately yields up to 8.9 eV energy, which is nearly 1.0 eV more than the formation energy for an isolated monovacancy. Processes resulting in vacancy coalescence and annihilation appear to be responsible for the main Wigner energy release peak in radiation-damaged graphite, occurring at about 475 K.

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Metastable Frenkel Pair Defect in Graphite: Source of Wigner Energy?

Cited by 143 publications

References 25 publications

Modifying the electronic structure of semiconducting single-walled carbon nanotubes byAr+ion irradiation

Modifying the electronic structure of semiconducting single-walled carbon nanotubes byAr+ion irradiation

Structural Defects in Graphene

The contribution made by lattice vacancies to the Wigner effect in radiation-damaged graphite

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