Parity conservation in electron-phonon scattering in zigzag graphene nanoribbon

Chu, Yanbang; Gautreau, Pierre; Basaran, Cemal

doi:10.1063/1.4895553

Cited by 17 publications

(8 citation statements)

References 16 publications

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“…It is the first two-dimensional material and it was obtained by mechanical exfoliation in 2004 (Novoselov et al, 2004). Since its discovery, graphene attracted extensive attention of researchers because of its extraordinary mechanical (Ovid'ko, 2013), thermal (Balandin, 2011), and electrical properties (Chu et al, 2015a(Chu et al, , 2014a(Chu et al, , 2016. One of the most promising applications of graphene is in nanoelectronics since it is highly conductive (Balandin et al, 2008), has very low Joule heating (Balandin, 2011), highly transparent (Kim et al, 2009), and extremely strong and flexible (Ovid'ko, 2013).…”

Section: Introductionmentioning

confidence: 99%

Comparison of fracture behavior of defective armchair and zigzag graphene nanoribbons

Ragab

Basaran

2018

International Journal of Damage Mechanics

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Molecular dynamics simulations of armchair graphene nanoribbons and zigzag graphene nanoribbons with different sizes were performed at room temperature. Double vacancy defects were introduced in each graphene nanoribbon at its center or at its edge. The effect of defect on the mechanical behavior was studied by comparing the stress-strain response and the fracture toughness of each pair of pristine and defective graphene nanoribbon. Results show that the effect of vacancies in zigzag graphene nanoribbon is more profound than in armchair graphene nanoribbon. Also, the effect of double vacancy defect on the ultimate failure stress is greater in zigzag graphene nanoribbons than in armchair graphene nanoribbon due to bond orientation with respect to loading direction. Strength reduction can be as high as 17.5% in armchair graphene nanoribbon with no significant difference between single and double vacancies, while for zigzag graphene nanoribbon, the strength reduction is up to 30% for single vacancy and 43% for double vacancy defects. It is observed that for zigzag graphene nanoribbon with double vacancy at the edge, the direction of the failure plane is oriented at AE30 with respect to the loading direction while it is always perpendicular to the direction of loading in armchair graphene nanoribbon. Results have been verified through studying the fracture toughness parameters in each case as well.

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Section: Introductionmentioning

confidence: 99%

Comparison of fracture behavior of defective armchair and zigzag graphene nanoribbons

Ragab

Basaran

2018

International Journal of Damage Mechanics

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“…Graphene was considered as the building block material for fullerene, carbon nanotube and graphite. The excellent thermal (Balandin, 2011), mechanical (Chu et al, 2014b(Chu et al, , 2015c and electrical (Chu, 2015;Chu et al, 2014aChu et al, , 2015bChu et al, , 2016 properties of graphene make it most likely to be the next generation material in nanoelectronics (Areshkin and White, 2007;Westervelt, 2008), nanoelectromechanical systems (NEMS) (Bunch et al, 2007;Standley et al, 2008) and nanocomposites (Stankovich et al, 2006) with greatest potential.…”

Section: Introductionmentioning

confidence: 99%

Influence of vacancy defects on the damage mechanics of graphene nanoribbons

Ragab

Basaran

2016

International Journal of Damage Mechanics

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Using molecular dynamics simulations, graphene nanoribbons with armchair chirality were subjected to displacement-controlled uniaxial tension until complete fracture at 300 K in order to understand their damage mechanics. Graphene nanoribbons with and without a vacancy defect were simulated to compare the effect of the defect on the fracture behavior. Simulations were performed for graphene nanoribbons with lengths ranging from 2.5 to 15 nm. The stress-strain curve of each case is reported, and the influence of defect on the material properties is discussed. For each sample, damage mechanics types were observed and discussed. Results show a negligible effect of the single vacancy defect on the ultimate strength of the graphene nanoribbon. However, having a single vacancy defect does influence the failure strain, as well as the damage mechanics past the ultimate stress point.

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“…The physics behind our method is that any arbitrary atomic vibration can be considered to be a superposition of the elementary vibrations, and the mathematics underlying this method is that any arbitrary vector can be expressed by the linear combination of a set of basis vectors. Note that if the phonon-associated property is zero, such as the electron-phonon coupling strength in zigzag graphene nanoribbons with even dimers (due to the selection rule of the parity conservation) [31], then the contribution of each BM is also zero. Similar projection procedures have been applied for other purposes, such as unfolding the phonon dispersions of a supercell into the 1st BZ of the primitive cell [32][33][34][35][36][37].…”

Section: Resultsmentioning

confidence: 99%

How to resolve a phonon-associated property into contributions of basic phonon modes

Cheng¹,

Zhang²,

Liu³

2019

J. Phys. Mater.

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Many properties of materials are associated with phonons. To better understand the phonon-property relation, it is a common practice to decompose the phonon-associated property into the contributions of basic phonon/vibration modes (e.g. longitudinal/transverse acoustic/optical mode), and identify the mode(s) that dominate(s) the property. The existing methods rely on labelling the phonon into one of the basic modes (BMs), however, the vibration characteristics of many phonons are different from the definitions of BMs, indicating these methods may give wrong decomposition results. Here we present a new method based on treating the phonon as a mixture of the BMs. By aligning the wave vectors and then projecting the phonon eigenvector onto the eigenvectors of the BMs, we can obtain the weights of the BMs on the given phonon, which can be used to quantify the contribution of each BM to the property. As an example, we apply this method to unravel the phonon modes that dominate the scattering of the electrons at the conduction band edge in two-dimensional antimony, an emerging semiconductor that has attracted great interest for electronics, but its mobility-limiting factors remain unclear. We find that the electron scattering is dominated by the out-of-plane acoustic phonon mode followed by the longitudinal acoustic mode, which are different from the results of other methods. Our method is generally applicable to different kinds of phonon-related properties and to all crystal materials.

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Parity conservation in electron-phonon scattering in zigzag graphene nanoribbon

Cited by 17 publications

References 16 publications

Comparison of fracture behavior of defective armchair and zigzag graphene nanoribbons

Comparison of fracture behavior of defective armchair and zigzag graphene nanoribbons

Influence of vacancy defects on the damage mechanics of graphene nanoribbons

How to resolve a phonon-associated property into contributions of basic phonon modes

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