Photoelastic properties of graphenes

The components of the elastooptic tensor of graphenes with the sp ² hybridization of atomic orbitals for the visible and near infrared spectral regions are calculated. These components are shown to be comparable with those of lithium niobate.

     

Flexural waves in graphene and 2D supracrystals

A method has been proposed for the calculation of the phase and group velocities of flexural waves in one-atom-thick graphene-like structures. The method is based on the expression for the flexural modulus in terms of the two-dimensional Young??s modulus. The method is also applicable to studying the characteristics of swelling waves in single-walled nanotubes of a sufficiently large diameter.     

Young’s modulus and the Poisson’s ratio of planar and nanotubular supracrystalline structures

A method has been proposed for calculating the two-dimensional Young??s modulus and the Poisson??s ratio for planar and nanotubular structures through the components of the two-dimensional elastic rigidity tensor obtained by numerical methods. The method has been tested for graphene and two-dimensional supracrystalline sheets.     

Elastic characteristics of 2D carbon supracrystals as compared to graphene

The constants of the central and noncentral interactions between carbon atoms in 2D supracrystals, i.e., generalized two-dimensional crystals in which the sites of the lattice contain, instead of individual atoms, their symmetric complexes, have been calculated. It has been shown that these constants essentially depend on the symmetry of the 2D supracrystal and can significantly differ from the corresponding constants for graphene.     

Piezoelectric effect in graphene-like 2D supracrystals with a periodic perforation breaking the central symmetry

Components of the piezoelectric modulus tensor in graphene-like carbon 2D supracrystals with a periodic perforation breaking the centrosymmetry of the structure have been calculated. It has been shown that the piezoelectric moduli of the supracrystals with sp ² hybridization are one order of magnitude lower and those of the supracrystals with sp ³ hybridization are several time higher than in lithium niobate.     

Elastic waves in carbon 2D supracrystals

The elastic moduli and propagation velocities of elastic waves in 2D supracrystalline nanoallotropes of carbon have been calculated. It has been shown that these velocities in sp ² nanoallotropes are close to those in graphene and exceed the propagation velocities of elastic waves in single-crystal diamond by a factor of 2. The propagation velocities of both longitudinal and transverse elastic waves in carbon 2D supracrystalline sp ³ nanoallotropes are several times lower than those in sp ² nanoallotropes.     

Piezoeffect in fluorographane-like 2D supracrystals

The components of the tensor of piezoelectric constants of fluorographane-like 2D supracrystals have been calculated. It has been shown that their values can be higher than those of lithium niobate. The obtained results can be used in the development of piezotransducers for the excitation and detection of terahertz elastic waves in nanoribbons and nanotubes.     

Elastic and acoustic characteristics of a three-dimensional carbon supracrystal (C)CTO

The force constants of the central and noncentral interactions of carbon atoms in a three-dimensional supracrystal (C)_CTO have been calculated using the ab initio and Harrison bond-orbital methods. The components of the elastic rigidity tensor and the propagation velocity of elastic waves in the supracrystal have been calculated. The results are close in magnitude to corresponding characteristics of diamond.