Energetics and structure of grain boundary triple junctions in graphene

Hirvonen, Petri; Fan, Zheyong; Ervasti, Mikko M.; Harju, Ari; Elder, K. R.; Ala-Nissilä, Tapio

doi:10.1038/s41598-017-04852-w

Cited by 24 publications

(23 citation statements)

References 48 publications

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“…Dislocations play a key role in determining material properties and grain boundary structures [17,19,31]. In graphene, the dislocations often form a Stone-Wales defect which is comprised of a 5/7 pair of rings instead of the six-ring equilibrium honeycomb structure that is illustrated in Fig.…”

Section: Dislocation Dipole In Graphenementioning

confidence: 99%

“…It possible to exploit PFC-type models as initial conditions for MD and DFT calculations to significantly reduce relaxation times. Such an approach has been used for MD studies of thermal conductivity in graphene and hBN [17][18][19][20] and MD and DFT studies of grain boundaries, triple junctions, and polycrystals in graphene [26,31,32]. However, compared to atomistic approaches, the PFC modeling can address much larger length and timescales.…”

Section: Introductionmentioning

confidence: 99%

“…These calculations are followed by a section devoted to stacks of 2D layers, with particular emphasis on graphene/graphene, hBN/hBN and graphene/hBN flexible bilayers. The individual layers are characterized by the graphene and hBN models developed in prior work [26][27][28]31,32] extended to incorporate OPDs. A relatively simple coupling between the planes is introduced to match the stacking energies and distances between layers to those calculated in prior DFT calculations by Zhou et al [40] as a continuous function of the stacking orientation.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Modeling buckling and topological defects in stacked two-dimensional layers of graphene and hexagonal boron nitride

Elder

Achim

Heinonen

et al. 2021

Phys. Rev. Materials

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In this paper, a two-dimensional phase field crystal model of graphene and hexagonal boron nitride (hBN) is extended to include out-of-plane deformations in stacked multilayer systems. As proof of principle, the model is shown analytically to reduce to standard models of flexible sheets in the small deformation limit. Applications to strained sheets, dislocation dipoles, and grain boundaries are used to validate the behavior of a single flexible graphene layer. For multilayer systems, parameters are obtained to match existing theoretical density functional theory calculations for graphene/graphene, hBN/hBN, and graphene/hBN bilayers. More precisely, it is shown that the parameters can be chosen to closely match the stacking energies and layer spacing calculated by Zhou et al. [Phys. Rev. B 92, 155438 (2015)]. Further validation of the model is presented in a study of rotated graphene bilayers and stacking boundaries. The flexibility of the model is illustrated by simulations that highlight the impact of complex microstructures in one layer on the other layer in a graphene/graphene bilayer.

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Section: Dislocation Dipole In Graphenementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Modeling buckling and topological defects in stacked two-dimensional layers of graphene and hexagonal boron nitride

Elder

Achim

Heinonen

et al. 2021

Phys. Rev. Materials

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show abstract

“…Furthermore, interfaces with long segment lengths proved stable as the highly symmetric initial states provided insufficient driving force to overcome the energy barriers for nucleating more vertices. Related point defects, triple junctions between grain boundaries, have also been shown to display negative formation energies [56][57][58] .…”

Section: Interface Energiesmentioning

confidence: 99%

Phase-field crystal model for heterostructures

et al. 2019

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Atomically thin 2-dimensional heterostructures are a promising, novel class of materials with groundbreaking properties. The possiblity of choosing the many constituent components and their proportions allows optimizing these materials to specific requirements. The wide adaptability comes with a cost of large parameter space making it hard to experimentally test all the possibilities. Instead, efficient computational modelling is needed. However, large range of relevant time and length scales related to physics of polycrystalline materials poses a challenge for computational studies. To this end, we present an efficient and flexible phase-field crystal model to describe the atomic configurations of multiple atomic species and phases coexisting in the same physical domain. We extensively benchmark the model for two-dimensional binary systems in terms of their elastic properties and phase boundary configurations and their energetics. As a concrete example, we demonstrate modelling lateral heterostructures of graphene and hexagonal boron nitride. We consider both idealized bicrystals and large-scale systems with random phase distributions. We find consistent relative elastic moduli and lattice constants, as well as realistic continuous interfaces and faceted crystal shapes. Zigzag-oriented interfaces are observed to display the lowest formation energy.

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“…While simple random Voronoi tessellations correctly predict the log-normal distribution of grain sizes [52], it is clear that they do not give realistic grain misalignment distributions. Here there is actual physics involved, related to the interactions and anisotropy of the grain boundaries present, and PFC is able to capture such properties [12,45]. Figure 23 shows the grain circularity distributions for the four lattice types.…”

Section: Microstructural Analysis Of Different Lattice Types: Furthermentioning

confidence: 99%

Grain extraction and microstructural analysis method for two-dimensional poly and quasicrystalline solids

Hirvonen

Boissonière

Fan

et al. 2018

Phys. Rev. Materials

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While the microscopic structure of defected solid crystalline materials has significant impact on their physical properties, efficient and accurate determination of a given polycrystalline microstructure remains a challenge. In this paper we present a highly generalizable and reliable variational method to achieve this goal for two-dimensional crystalline and quasicrystalline materials. The method is benchmarked and optimized successfully using a variety of large-scale systems of defected solids, including periodic structures and quasicrystalline symmetries to quantify their microstructural characteristics, e.g., grain size and lattice misorientation distributions. We find that many microstructural properties show universal features independent of the underlying symmetries.

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Energetics and structure of grain boundary triple junctions in graphene

Cited by 24 publications

References 48 publications

Modeling buckling and topological defects in stacked two-dimensional layers of graphene and hexagonal boron nitride

Modeling buckling and topological defects in stacked two-dimensional layers of graphene and hexagonal boron nitride

Phase-field crystal model for heterostructures

Grain extraction and microstructural analysis method for two-dimensional poly and quasicrystalline solids

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