E 58 Enyashin, A. N. Mechanical and electronic properties of a C/BN nanocable under tensile deformation [] / A. N. Enyashin, A. L. Ivanovskii // Nanotechnology. - 2005. - V. 16, N 8. - С. 1304-1310. - Bibliogr.: p. 1309-1310 (48 ref.) . - ISSN 0957-4484 Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ЭЛЕКТРОННЫЕ СВОЙСТВА -- МЕХАНИЧЕСКИЕ СВОЙСТВА -- СВОЙСТВА ЭЛЕКТРОННЫЕ -- СВОЙСТВА МЕХАНИЧЕСКИЕ -- ДЕФОРМАЦИЯ -- НАПРЯЖЕНИЕ -- КАРБОНОВЫЕ НАНОТРУБКИ -- НАНОТРУБКИ КАРБОНОВЫЕ -- БОРОНИТРИДНЫЕ НАНОТРУБКИ -- НАНОТРУБКИ БОРОНИТРИДНЫЕ Аннотация: Atomistic simulations are performed to investigate the structural, mechanical and electronic properties of a coaxial C/BN nanocable under axial elongation using molecular dynamics. Our results show that the mechanism of the breaking process essentially differs from those for initial single-walled carbon and BN nanotubes. The formation of a carbon as well as a -C-B-N-atomic chain connecting two cable fragments before fracture is obtained, and due to such bridges the cable can be stretched until complete rupture up to epsilon max~29% as compared with epsilon max~23% for a single-walled carbon nanotube. After breakage the opposite tips of cable fragments form different individual atomic morphologies and compositions and can have promising potential as electron emitters. The Young moduli of the C/BN cable and C-NT are comparable. An analysis of the electronic structure shows that during tensile deformation the C/BN cable retains the basic electronic characteristics (metallic-like for the inner carbon nanotube and dielectric for the outer BN tube); however, the bandgap between the highest occupied N 2p and lowest unoccupied B 2p states decreases from 4.0 to 1.2 eV |
E 43 Electronic Properties of New Ca(AlxSi1 – x)2 and Sr(GaxSi1 – x)2 Superconductors in Crystalline and Nanotubular States / I. R. Shein, V. V. Ivanovskaya, N. I. Medvedeva, A. L. Ivanovskii // JETP Letters. - 2002. - Vol. 76, № 3. - P. 189-193 : il. - Bibliogr. : p. 193 (19 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): СВЕРХПРОВОДНИКИ -- НАНОТРУБКИ КАРБОНОВЫЕ -- SrGaSi -- CaAlSi Аннотация: The band structure of new layered (AlB2 type) Ca(AlxSi1 – x)2 and Sr(GaxSi1 – x)2 superconductors is studied by the first-principle full-potential LMTO method. It has been shown that the superconducting properties of ternary silicides are due to the high density of (Ca,Sr)d states at the Fermi level, whereas the growth of TC in going from Sr(GaxSi1 – x)2 to Ca(AlxSi1 – x)2 is associated with the increase in phonon frequencies due to the decrease in atomic masses. Simulations are performed for the electronic properties of hypothetical (11,11) and (20,0) CaAlSi and SrGaSi nanotubes. In going from the crystalline to the nanotubular state, the silicide systems retain metal-like properties. The template and “film rolling” techniques can be used for obtaining silicide nanotubes Полный текст |
E 58 Enyashin, A. N. Structural, Elastic, and Electronic Properties of New Superhard Isotropic Cubic Crystals of Carbon Nanotubes / A. N. Enyashin, A. L. Ivanovskii // JETP Letters. - 2008. - Vol. 87, № 6. - P321-325 : il. - Bibliogr. : p. 325 (30 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): НАНОТРУБКИ КАРБОНОВЫЕ -- ИЗОТРОПНЫЕ КУБИЧЕСКИЕ КРИСТАЛЛЫ Аннотация: The models of new isotropic cubic crystals of single-layered carbon nanotubes are proposed. The structural, elastic, and electronic properties and the energies of formation of these crystals were calculated using the density functional-based tight binding (DFTB) method. The crystals proposed were found to exhibit extreme compression moduli (550–650 GPa) and a minimum compressibility (0.0018–0.0015 GPa–1); in this case, the type of conduction of the parent nanotubes was retained. For this reason, the above crystals are of interest for the development of new superhard materials with controllable electrophysical properties Полный текст |
E 43 Electronic Properties and Chemical Bonds of 3d Atoms in Carbon Nanotubes and Metallocarbohedrenes / A. A. Sofronov, V. V. Ivanovskaya, Yu. N. Makurin, A. L. Ivanovskii // Russian Journal of Coordination Chemistry. - 2002. - Vol. 28, № 9. - P618-629 : il. - Bibliogr. : p. 628-629 (29 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): НАНОТРУБКИ КАРБОНОВЫЕ -- ФУЛЛЕРЕНЫ -- КАРБИД ТИТАНА Аннотация: The electronic states of 3d atoms (M = Ti, Cr, Fe, and Cu) intercalated into the bulk of carbon nanotubes (NT) or replacing the titanium atom in carbohedrene Ti8C12 are studied by the ab initio self-consistent discrete variation method. The electronic state, charge distributions, and parameters of interatomic interactions are analyzed in nanotubular composites M@NT depending on the NT structure ((9.0) or (4.4)) and position of the M atom (at the end or in the center of the NT) and depending on the cluster symmetry (Th or Td) and positions of M atoms in the metal–carbon cage for “substituted” metcars Ti7MC12. Possible changes in some physicochemical properties of the nanotubes and metallocarbohedrenes with the indicated 3d atoms are discussed Полный текст |