Electronic and optical properties of carbon supracrystalline <Emphasis Type="Italic">sp</Emphasis> <Subscript>2</Subscript> nanoallotropes

Electronic and optical properties of 2D conducting carbon supracrystals are studied. The band structure is calculated using the tight-binding method. One sample is classified as semimetal, and the remaining samples are classified as narrow-band-gap semiconductors. The optical conductivity of the supracrystalline structures is calculated. It is demonstrated that the conductivity of semimetal supracrystals may be substantially higher than the grapheme conductivity. Complex refractive indices of the supracrystals are estimated.     

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.

     

Propagation of electromagnetic waves in conducting graphene-like carbon nanoallotropes

Propagation of electromagnetic waves in graphene-like conducting carbon crystals with the (C)_4ν and (C)_6ν symmetries is studied. It is demonstrated that only TM waves can exist in such crystals. The comparative analysis of such waves in different structures is performed. It is shown that the structures under study are superior to classical graphene with respect to excitation of electromagnetic waves.     

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.     

Waveguide propagation of internal electrohydrodynamic waves in heterojunctions

We analyze the propagation of internal electrohydrodynamic waves, which were predicted for impurity semiconductors with a free-carrier density gradient, in an isotypic n-n⁺ heterojunction. Ulyanovsk State Technical University, Ulyanovsk, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 43, No. 5, pp. 452–455, May. 2000.     

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.     

Negative optical refraction in crystals with strong birefringence

The possibility of negative optical refraction of the extraordinary ray in crystals with strong birefringence is demonstrated.