M 17 Magnetism without magnetic ions in non-magnetic perovskites SrTiO3, SrZrO3 and SrSnO3 [Text] / V. V. Bannikov, I. R. Shein, V. L. Kozhevnikov, A. L. Ivanovskii // Journal of Magnetism and Magnetic Materials. - 2008. - Vol. 320, № 6. - P936-942. - Bibliogr. : p. 941-942 (46 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ПЕРОВСКИТЫ -- МАГНЕТИЗМ -- ПЕРВОПРИНЦИПНЫЕ РАСЧЕТЫ Аннотация: Using the full-potential linearized augmented plane-wave (FP-LAPW) method with the generalized gradient approximation (GGA) for the exchange-correlation potential, we studied spin polarization induced by replacement of oxygen atoms by non-magnetic 2p impurities (B, C and N) in non-magnetic cubic SrMO3 perovskites, where M ¼ Ti, Zr and Sn. The results show that the magnetization may appear because of the spin–split impurity bands inside the energy gap of the insulating SrMO3 matrix. Large magnetic moments are found for the impurity centers. Smaller magnetic moments are induced on the oxygen atoms around impurities. It is shown that SrTiO3:C and SrSnO3:C should be magnetic semiconductors while other compounds in this series (SrTiO3:B, SrTiO3:N and SrZrO3:C) are expected to exhibit magnetic half-metallic or pseudo-half-metallic properties Полный текст |
S 53 Electronic properties of ThSiO4 polymorphs (thorite and huttonite) from first principles calculations [Text] / I. R. Shein, K. I. Shein, N. I. Medvedeva, A. L. Ivanovskii // Physica status solidi B. - 2006. - Vol. 243. - PR44-R46. - Bibliogr. : p. R46 (15 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): СИЛИКАТ ТОРИЯ -- ПЕРВОПРИНЦИПНЫЕ РАСЧЕТЫ -- ПОЛИМОРФИЗМ Аннотация: The full-potential linearized augmented plane wave method with the generalized gradient approximation for the exchange and correlation potential (FLAPW-GGA) is used to understand the electronic properties of the tetragonal (thorite) and monoclinic (huttonite) polymorphs of thorium orthosilicate and charge density were obtained for the first time and applied to describe the chemical bonding. Both ThSiO4 phases are insulating; the Th 5f states are itinerant and overlap with O 2p bands, the chemical bonding in the both phases is a combination of covalent and ionic typesThSiO4. Electronic bands, total and partial density of states Полный текст |
E 43 Electronic and magnetic properties of beryllium oxide with 3d impurities from first-principles calculations [Текст] / M. A. Gorbunova, I. R. Shein, Yu. N. Makurin, V. S. Kiiko, A. L. Ivanovskii // Physica B: Condensed Matter (Amsterdam, Netherlands). - 2007. - Vol. 400, № 1-2. - С. 47-52. - Bibliogr. : p. 52 (35 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ОКСИД БЕРИЛЛИЯ -- ПЕРВОПРИНЦИПНЫЕ РАСЧЕТЫ -- ЭЛЕКТРОМАГНИТНЫЕ СВОЙСТВА Аннотация: The ab initio VASP–PAW method with the generalized gradient approximation (GGA) has been applied to predict the electronic and magnetic properties of wurtzite-like beryllium oxide (BeO) doped with all 3d metals. Adding of 3d metal ions into BeO transforms the initial non-magnetic insulator BeO into series of magnetic and non-magnetic materials with various functional properties Полный текст |
S 53 Shein, I. R. Elastic and electronic properties and stability of SrThO3, SrZrO3 and ThO2 from first principles [Текст] / I. R. Shein, K. I. Shein, A. L. Ivanovskii // Journal of Nuclear Materials. - 2007. - Vol. 361, № 1. - С. 69-77. - Bibliogr. : p. 76-77 (54 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ТОРИЙ -- СТРОНЦИЙ -- ПЕРВОПРИНЦИПНЫЕ РАСЧЕТЫ Аннотация: First-principle calculations in the framework of the full-potential linearized-augmented-plane-wave method (FLAPW, as implemented into the WIEN-2k code) have been performed to understand the structural, elastic, cohesive and electronic properties of the meta-stable cubic strontium thorate SrThO3. The optimized lattice parameters, elastic parameters, formation energies, densities of states, band structures and charge density distributions are obtained and discussed in comparison with those of cubic SrZrO3 and ThO2 Полный текст |
E 43 Electronic band structure of thorium hydrides: ThH2 and Th4H15 [Текст] / I. R. Shein, K. I. Shein, N. I. Medvedeva, A. L. Ivanovskii // Physica B: Condensed Matter (Amsterdam, Netherlands). - 2007. - Vol. 389, № 2. - С. 296-301. - Bibliogr. : p. 300-301 (27 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ГИДРИД ТОРИЯ -- ПЕРВОПРИНЦИПНЫЕ РАСЧЕТЫ -- ПЛОТНОСТЬ Аннотация: First principle calculations were performed using full-potential LAPW method with generalized gradient approximation (FLAPWGGA) to understand the electronic properties of thorium hydride Th4H15 and compare with those for alpha-Th and ThH2. The equilibrium geometries, the electronic band structure, the total and partial densities of states for these materials are obtained and analyzed in comparison with the available experimental data. We found that the Th6d and Th5f states give comparable contributions to NðEFÞ in alpha-Th, whereas only one of them, namely the Th6d or Th 5f states determine the largest contribution in ThH2 and Th4H15, respectively. We estimated the average electron–phonon coupling constant l to be 0.38 and concluded that Th4H15 may be considered as a weak coupling superconductor Полный текст |
S 53 Shein, I. R. First-principle study of B1-like thorium carbide, nitride and oxide [Текст] / I. R. Shein, K. I. Shein, A. L. Ivanovskii // Journal of Nuclear Materials. - 2006. - Vol. 353, № 1-2. - С. 19-26. - Bibliogr. : p. 26 (28 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): КАРБИД ТОРИЯ -- НИТРИД ТОРИЯ -- ОКСИД ТОРИЯ -- ПЕРВОПРИНЦИПНЫЕ РАСЧЕТЫ Аннотация: The electronic properties of cubic (B1-type) thorium carbide (ThC), nitride (ThN) and meta-stable monoxide (ThO) were calculated systematically using the full-potential linearized augmented plane wave method with the generalized gradient approximation for the exchange and correlation potential (LAPW–GGA). The structural parameters, bulk modulii, electronic bands, densities of states (DOS), charge distributions were obtained and compared with available experimental data and other calculations. The theoretical spectra of non-metal K-edge X-ray emission (XES) and absorption (XAS) of these materials are presented and discussed Полный текст |
S 53 Shein, I. R. Influence of lattice vacancies on the structural, electronic, and cohesive properties of niobium and molybdenum borides from first-principles calculations [Text] / I. R. Shein, A. L. Ivanovskii // Physical Review B: Condensed Matter and Materials Physics. - 2006. - Vol. 73, № 14. - P144108/1-144108/9. - Библиогр. : с. 144108/8 (55 назв.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): БОРИД МОЛИБДЕНА -- БОРИД НИОБИЯ -- ПЕРВОПРИНЦИПНЫЕ РАСЧЕТЫ Аннотация: The influence of lattice vacancies on the structural, cohesive, and electronic properties of Nb and Mo borides were examined by means of the full-potential linearized augmented plane wave method and the generalized gradient approximation. The structural parameters, densities of states (DOS), charge distribution, heats of formations, and vacancy formation energies for metal-deficient hexagonal Nb1−xB2, Mo1−xB2 as well as for boron-deficient rhombohedral Mo2B5−y were obtained and compared with those for complete hexagonal NbB2, MoB2 and rhombohedral Mo2B5. We show that the presence of metal vacancies in hexagonal phases leads to (i) the decreasing of in-plane parameter a but increasing the interplane cell parameter c; (ii) well pronounced changes of near-Fermi DOS and the appearance of the novel vacancy states; and (iii) a substantial decrease in the stability of borides. On the contrary, in the case of Mo2B5 the appearance of the boron vacancies leads to enhancing of stability of a rhombohedral phase Полный текст |
F 56 First-principles study of deformation behavior and structural defects in CuInSe2 and Cu(In,Ga)Se2 [Текст] / N. I. Medvedeva, E. V. Shalaeva, M. V. Kuznetsov, M. V. Yakushev // Physical Review B: Condensed Matter and Materials Physics. - 2006. - Vol. 73, № 3. - С. 035207/1-035207/6. - Библиогр. : с. 035207/5 (39 назв.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ПЕРВОПРИНЦИПНЫЕ РАСЧЕТЫ -- СЕЛЕНИД ИНДИЯ -- СЕЛЕНИД ГАЛЛИЯ -- СЕЛЕНИД МЕДИ Аннотация: Electronic structure and total-energy calculations have been performed for CuInSe2 and Cu In,Ga Se2 using density-functional theory with generalized gradient corrections. To understand the fracture and deformation behavior in chalcopyrites, we calculated the cleavage and generalized stacking fault energies in CuInSe2 and Cu(In,Ga)Se2 and demonstrated a brittle character of crack propagation. Antiphase boundary and intrinsic stacking fault defects have low formation energies and are quite probable in these chalcopyrites. The main slip system and preferable cleavage plane should be (110)(112) and (112), respectively. For the (110)(001) and (110)(001) dislocations in CuInSe2, we predict a strong tendency for splitting in two partials Полный текст |