Elastic properties of diamond-like phases based on carbon nanotubes

Rysaeva, Leysan Kh.; Baimova, Julia A.; Lisovenko, D. S.; Городцов, В. А.; Rudskoy, A. I.

doi:10.1016/j.diamond.2019.04.034

Cited by 31 publications

(20 citation statements)

References 101 publications

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“…A significant deviation of the valence angles from these values usually results in high strains and low stability of the system. However, some novel carbon architectures (fullerites [1], curved nanotubes [2], 4 -8 graphene sheets [3], diamond-like phases, based on nanotubes [4] or graphene [5], hypercubane [6], etc.) include the valence angles of 90°.…”

Section: Introductionmentioning

confidence: 99%

Ab initio modeling of dynamic stability of silicon prismanes

2020

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We present the results of a study on the dynamic stability of silabiprismanes by means of the density functional theory. Silabiprismanes present an elementary case of a particular type of silicon nanotubes with an extremely small cross-section, constructed from dehydrogenated molecules of cyclosilanes (silicon rings). Unlike higher polysilaprismanes, they are formed by only three silicon rings and described by the chemical formula (Si n) 3 H 2n. In the presented study, we limited ourselves to the cases n = 5 ÷ 7. We focused on a detailed review of the mechanisms of isomerization and decomposition. Configurations of the corresponding transition states were determined, and the kinetic parameters in the Arrhenius law (activation energy and frequency factor) were evaluated. Silabiprismanes are found to be much more stable compounds than their carbon analogous. Their lifetimes at room temperature achieve hundreds of seconds, but at 200 K, their stability increases significantly. Thus, their lifetimes are sufficiently high for the identifying and studying of silicon biprismanes, but not for their industrial applications. Therefore, unsubstituted silabiprismanes require lower temperatures of operation, and their applicability is restricted. Although the general pyrolysis path is the same for all considered cages, its features strongly and non-monotonically depend on n. It is confirmed that the hexagonal and heptagonal silabiprismanes are much more stable than the pentagonal one. We obtained the absence of a direct correlation between the thermodynamic and kinetic stabilities of the silicon cages under consideration.

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Section: Introductionmentioning

confidence: 99%

Ab initio modeling of dynamic stability of silicon prismanes

2020

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“…Besides interest to SPPs itself, they are considered as promising building blocks for novel materials with more complicated structures. Carbon analogous of SPPs [14] are embedded into some new diamond-like allotropes [15,16] and form stable 1D [17,18], 2D [19,20] and 3D [18,21] structures. Similarly, SPPs can produce a family of silicon clusters and crystal forms with different dimensionalities.…”

Section: Introductionmentioning

confidence: 99%

The effect of doping on the electronic structure and optical properties of silicon biprismanes: DFT and TD-DFT studies

et al. 2020

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We present the results of a study of three-layered silicon biprismanes doped with methyl radicals and fluorine atoms by means of the density functional theory. Pentagonal, hexagonal, heptagonal, and octagonal doped systems were simulated in this study. We found that larger biprismanes demonstrate weaker interaction with dopants because they are less strained, and their surfaces are "flatter". The weakening of interaction manifests itself by elongation of bond lengths between the silicon cage and the attached radicals. However, the energy gain / loss due to the reaction of substitutional doping is practically independent of the size of the system. The calculated partial Mulliken charges of fluorine atoms are about −0.3 of elementary charges. The corresponding value for methyl radicals is approximately three times smaller. HOMO-LUMO gaps of doped biprismanes demonstrate oscillations with increasing biprismane diameter with a general downward trend. The value of the gaps of the doped biprismanes is in the range from 2 to 3 eV and slightly differs from the gaps of the pristine biprismanes. The optical properties and excited states of doped biprismanes were calculated using the time-dependent density functional theory. Ultraviolet and visible spectra were determined for all considered systems. The absorption frequencies slightly depend on the radical type and the size of the system. However, the presence of radicals results in significant changes in the relative adsorption intensities of biprismanes with different shapes. We found that doping with methyl radicals and fluorine provided prevalent adsorption intensities of octagonal and hexagonal biprismanes, respectively. The observed effect can be used for optical detection of biprismanes with specific shapes or diameters in their mixture with other silicon structures.

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“…Углерод -это уникальный химический элемент, на основе которого может быть сформировано огромное множество неорганических соединений, обладающих значительно отличающимися структурами и свойствами [1][2][3][4][5][6]. Хотя равновесными формами углерода при нормальных условиях являются графит и алмаз [7], но за последние тридцать пять лет также были синтезированы различные молекулярные, трубчатые и слоевые углеродные наноструктуры, состоящие из  гибридизированных атомов [7][8][9][10].…”

Section: Introductionunclassified

Structure and Stability of a Tetragonal Diamond-Like Layer: First-Principle Calculations

Грешняков¹,

Беленков²

2020

Physical and Chemical Aspects of the Study of Clusters, Nanostructures and Nanomaterials

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Методом теории функционала плотности было выполнено теоретическое исследование нового слоевого полиморфа алмаза DL, состоящего из двух полимеризованных тетрагональных графеновых слоев L. Установлено, что новый алмазоподобный слой имеет двумерную тетрагональную решетку с параметром a = b = 0,3822 нм и толщиной 0,1599 нм. Рассчитанные поверхностная плотность и ширина запрещенной зоны этого слоя равны 0,109 мкг/см и 2,63 эВ, соответственно. Новый слой DL должен быть устойчивым, как минимум, до 220 К. Также установлено, что слой DL может быть получен при сильном одноосном сжатии двух графеновых слоев L при давлении 29,6 ГПа. Using the density functional theory method, a theoretical study of a novel layered DL polymorph of diamond, consisting of two polymerized tetragonal graphene L layers, was performed. It was established that the new diamond-like layer has a two-dimensional tetragonal lattice with the parameter a = b = 0,3822 nm and a thickness of 0,1599 nm. The calculated surface density and band gap of this layer are 0,109 μg/cm and 2,63 eV, respectively. The new DL layer must be stable up to at least 220 K. It was also found that the DL layer can be obtained by strong uniaxial compression of two graphene L layers at a pressure of 29,6 GPa.

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Elastic properties of diamond-like phases based on carbon nanotubes

Cited by 31 publications

References 101 publications

Ab initio modeling of dynamic stability of silicon prismanes

Ab initio modeling of dynamic stability of silicon prismanes

The effect of doping on the electronic structure and optical properties of silicon biprismanes: DFT and TD-DFT studies

Structure and Stability of a Tetragonal Diamond-Like Layer: First-Principle Calculations

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