Diamond frequency distribution

The phonon spectra of the diamond lattice obtained for a sii le limiting frequency, different values of the anisotropy constant, and kj/kjj = const, (c44)j/(C44)jj = const, are characterized by the fact that an increase in the coefficient y = C44/ (C44 - C42) alters significantly the density of the frequency distribution in the low-frequency part of the acoustical branch, changing it from an almost linear dependence at y = 0.2 to a parabolic dependence at y -= 0.9 (Fig. 6). 

The capacitance of surface states is undoubtedly frequency-dependent. However, in order to ensure the linear C 2 vs. E dependence observed experimentally, one has to make very strict assumptions concerning the energy distribution function of the surface states, and this appears very unnatural. Therefore, a slow ionization, in the space charge region of a diamond crystal, of atoms with a relatively deep-lying... 

Strelnitskii et al. 32) reported a superdense carbon allotrope (4,100 kg-m ) obtained as carbon films formed by radio-frequency condensation of carbon plasmas on cooled substrates the crystalline phase, obtained along with amorphous phase, was studied by electron diffraction and revealed a primitive rhombohedral unit cell with 8 carbon atoms, hence this phase was called Cs, and its structure, as proposed by Stankevich et al. [33] and Biswas et al. [34], involved cubes connected by single bonds (supercubane). Burdett and Lee [9] found the supercubane structure to be less stable than diamond if the constituting atoms have 4 or less electrons per atom, but more stable for electron-rich systems (i. e. >4 electrons per atom). Johnston and Hoffmann [35], observing discrepancies in the crystallographic analysis and the unusual bond length distribution, found that a likely alternative structure for Cs is the body-centered BC-8 structure adopted by the high-pressure y- Si allotrope. 

The effect was investigated of the nature and energy of the interatomic interaction on the structure and physical properties of crystals. Factors were studied which determine the thermodynamic properties and their temperature dependences. The effect of various parameters on the form of the frequency spectmm of phonons was investigated, taking, as an example, crystals with a diamond-type structure. The problem was also studied of the determination of the elastic constants as derivatives of the crystal energy in terms of the distribution functions of the electron density, represented by various approximations. 

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