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1.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ivanova N. B., Ovchinnikov S. G., Korshunov M. M., Eremin I. M., Kazak N. V.
Заглавие : Specific features of spin, charge, and orbital ordering in cobaltites
Коллективы : RFBR [09-02-00171-a, 07-02-00226, 09-02-00127]; Federal Agency of Science and Innovation [MK-4278.2008.2]; Presidium of the Russian Academy of Sciences [5, 7]; Leading Science Schools of the Ministry of Education and Science of the Russian Federation [2.1.1/3199]
Место публикации : Phys. Usp.: Turpion Ltd, 2009. - Vol. 52, Is. 8. - P.789-810. - ISSN 1063-7869, DOI 10.3367/UFNe.0179.200908b.0837
Примечания : Cited References: 278. - This work was financially supported by the RFBR (projects 09-02-00171-a, 07-02-00226, and 09-02-00127), the Federal Agency of Science and Innovation (grant MK-4278.2008.2), and the Presidium of the Russian Academy of Sciences Program No. 5, Quantum Physics of Condensed Media (project No. 7). I.M.E.'s work was supported by the program for Leading Science Schools of the Ministry of Education and Science of the Russian Federation (grant 2.1.1/3199).
Предметные рубрики: PEROVSKITE-TYPE OXIDES
METAL-INSULATOR-TRANSITION
HIGH-TEMPERATURE SUPERCONDUCTIVITY
ONE-DIMENSIONAL CA3CO2O6
ELECTRONIC-STRUCTURE
MAGNETIC-PROPERTIES
TRANSPORT-PROPERTIES
STATE TRANSITION
FUEL-CELLS
CRYSTAL-STRUCTURE
Ключевые слова (''Своб.индексиров.''): cobalt oxides--lanthanides--orbital degrees of freedom--orbital ordering--quasi-one-dimensional--spin state--superconducting compounds--theoretical result--calcium--cobalt--lanthanum--oxide minerals--perovskite--spin dynamics--superconductivity--cobalt compounds
Аннотация: Complex cobalt oxides known as cobaltites are reviewed, including LnCoO(3)-based perovskite-structured rare-earth cobaltites (where Ln is lanthanum or a lanthanide), quasi-two-dimensional and quasi-one-dimensional cobaltites of the types LnCo(2)O(5+delta), La2CoO4, and Ca3Co2O8, and NaxCoO2 center dot yH(2)O superconducting compounds. Key experimental and theoretical results are presented, with emphasis on the interplay between charge, spin, and orbital degrees of freedom. Two problems of specific relevance to cobaltites - the spin state instability of Co3+ ions in LnCoO(3), and the nature of superconductivity in NaxCoO2 center dot yH(2)O - are also given significant attention.
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2.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ovchinnikov S. G.
Заглавие : Symmetry of holes in high-temperature superconductors
Место публикации : Solid State Commun. - 1991. - Vol. 77, Is. 3. - P.221-224. - ISSN 0038-1098, DOI 10.1016/0038-1098(91)90336-T
Примечания : Cited References: 19
Предметные рубрики: FERMI-LIQUID STATES
X-RAY ABSORPTION
ELECTRONIC-STRUCTURE
PHOTOEMISSION
BI2SR2CACU2O8
BISMUTH
Аннотация: A symmetry of holes is investigated in the multielectron band theory which takes into account strong correlations. It is shown that a small number of d(z2) states appears near the Fermi level due to d(z2) Cu-2p(x(y))O charge transfer as admixture to d(x2-y2)-p(x(y)) bands with dominant contribution of O2p states. The results are in a qualitative agreement with polarized photoemission data.
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3.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ovchinnikov S. G.
Заглавие : EFFECT OF ANTIFERROMAGNETIC ORDERING ON ZONE STRUCTURE OF LA2CUO4
Место публикации : Zhurnal Eksperimentalnoi Teor. Fiz.: MEZHDUNARODNAYA KNIGA, 1995. - Vol. 107, Is. 3. - P796-811. - ISSN 0044-4510
Примечания : Cited References: 42
Предметные рубрики: HIGH-TC SUPERCONDUCTORS
ELECTRONIC-STRUCTURE
OXIDE SUPERCONDUCTORS
CHARGE-TRANSFER
CUO2 PLANE
MODEL
HOLE
SPECTRUM
STATE
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4.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ovchinnikov S. G.
Заглавие : Modification of magnetic and superconducting properties of layered cuprates due to copper substitution for zinc and nickel
Место публикации : Fiz. Tverd. Tela: MEZHDUNARODNAYA KNIGA, 1995. - Vol. 37, Is. 12. - P3645-3654. - ISSN 0367-3294
Примечания : Cited References: 28
Предметные рубрики: ELECTRONIC-STRUCTURE
LA2CUO4
LA2-XSRXCUO4
EXCITATIONS
DENSITY
PLANE
NI
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5.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Avramov P. V., Sorokin P. B., Fedorov A. S., Fedorov D. G., Maeda Y.
Заглавие : Band-gap unification of partially Si-substituted single-wall carbon nanotubes
Место публикации : Phys. Rev. B: AMER PHYSICAL SOC, 2006. - Vol. 74, Is. 24. - Ст.245417. - ISSN 1098-0121, DOI 10.1103/PhysRevB.74.245417
Примечания : Cited References: 72
Предметные рубрики: SILICON-CARBIDE NANOTUBES
DENSITY-FUNCTIONAL THEORY
TOTAL-ENERGY CALCULATIONS
WAVE BASIS-SET
ELECTRONIC-STRUCTURE
AB-INITIO
NANORODS
EXCITATIONS
TRANSITION
NANOWIRES
Аннотация: The atomic and electronic structure of a set of pristine single wall SiC nanotubes as well as Si-substituted carbon nanotubes and a SiC sheet was studied by the local-density approximation (LDA) plane wave band structure calculations. Consecutive substitution of carbon atoms by Si leads to a gap opening in the energetic spectrum of the metallic (8,8) SWCNT with approximately quadratic dependence of the band gap upon the Si concentration. The same substitution for the semiconductor (10,0) single wall carbon nanotubes (SWCNT) results in a band gap minimum (0.27 eV) at similar to 25% of Si concentration. In the Si concentration region of 12-18 %, both types of nanotubes have less than 0.5 eV direct band gaps at the Gamma-Gamma point. The calculation of the chiral (8,2) SWSi0.15C0.85NT system gives a similar (0.6 eV) direct band gap. The regular distribution of Si atoms in the atomic lattice is by similar to 0.1 eV/atom energetically preferable in comparison with a random distribution. Time dependent density functional theory (DFT) calculations showed that the silicon substitution sufficiently increases (roughly by one order of magnitude) the total probability of optical transitions in the near infrared region, which is caused by the opening of the direct band gap in metallic SWCNTs, the unification of the nature and energy of the band gaps of all SWCNT species, the large values of Si3p parallel to r parallel to Si3s radial integrals and participation of Si3d states in chemical bonding in both valence and conductance bands.
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6.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gavrichkov V. A., Ovchinnikov S. G., Borisov A. A., Goryachev E. G.
Заглавие : Evolution of the band structure of quasiparticles with doping in copper oxides on the basis of a generalized tight-binding method
Место публикации : J. Exp. Theor. Phys.: AMER INST PHYSICS, 2000. - Vol. 91, Is. 2. - P369-383. - ISSN 1063-7761, DOI 10.1134/1.1311997
Примечания : Cited References: 45
Предметные рубрики: T-J MODEL
CUPRATE SUPERCONDUCTORS
ELECTRONIC-STRUCTURE
EXCITATIONS
DEPENDENCE
TEMPERATURE
DERIVATION
SR2CUO2CL2
SPECTRUM
DENSITY
Аннотация: Two methods for stabilizing the two-hole B-3(1g) state as the ground state instead of the Zhang-Rice singlet are determined on the basis of an orthogonal cellular basis for a realistic multiband pd model of a CuO2 layer and the dispersion relations for the valence band top in undoped and doped cases are calculated. In the undoped case, aside from the valence band, qualitatively corresponding to the experimental ARPES data for Sr2CuO2Cl2 and the results obtained on the basis of the t-t'-J model, the calculations give a zero-dispersion virtual level at the valence band top itself. Because of the zero amplitude of transitions forming the virtual level the response corresponding to it is absent in the spectral density function. In consequence, the experimental ARPES data do not reproduce its presence in this antiferromagnetic undoped dielectric. A calculation of the doped case showed that the virtual level transforms into an impurity-type band and acquires dispersion on account of the nonzero occupation number of the two-hole states and therefore should be detected in ARPES experiments as a high-energy peak in the spectral density. The computed dispersion dependence for the valence band top is identical to the dispersion obtained by the Monte Carlo method, and the ARPES data for optimally doped Bi2Sr2CaCu2O8 + delta samples. The data obtained also make it possible to explain the presence of an energy pseudogap at the symmetric X point of the Brillouin band of HTSC compounds. (C) 2000 MAIK "Nauka/Interperiodica".
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7.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gavrichkov V. A., Borisov A. A., Ovchinnikov S. G.
Заглавие : Polarized ARPES spectra of undoped cuprates
Место публикации : Phys. Solid State: AMER INST PHYSICS, 2001. - Vol. 43, Is. 10. - P1876-1884. - ISSN 1063-7834, DOI 10.1134/1.1410625
Примечания : Cited References: 15
Предметные рубрики: ELECTRONIC-STRUCTURE
COPPER OXIDES
PHOTOEMISSION
EVOLUTION
MODEL
HOLE
Аннотация: The spectral density (SD) in the ARPES spectra of anti ferromagnetic (AFM) dielectrics Sr2CuO2Cl2 and Ca2CuO2Cl2 along the principal symmetry directions of the Brillouin zone was studied by the generalized tight binding method. At the valence band top of these undoped cuprates in the AFM state, there is a pseudogap of magnetic nature with E-s(k) similar to 0-0.4 eV between a virtual level and the valence band proper. The observed similarity of dispersion along the Gamma -M and X-Y directions can be explained by the proximity of the B-3(1g) triplet and the Zhang-Rice singlet levels. The value of parity of the polarized ARPES spectra at the Gamma, M, and X points calculated for the AFM phase of undoped cuprates with an allowance for the partial contributions is even. The conditions favoring observation of the partial contributions in polarized ARPES spectra are indicated. Due to the spin fluctuations, the virtual level acquires dispersion and possesses a small spectral weight. Probably, this level cannot be resolved on the background of the main quasi-particle peak as a result of the damping effects. (C) 2001 MAIK "Nauka/Interperiodica".
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8.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ovchinnikov S. G., Burkova L. V., Seredkin V. A., Yakovchuk V. Y.
Заглавие : An analysis of the mechanism of Kerr effect enhancement in Mn/Dy/Bi
Место публикации : Phys. Solid State: AMER INST PHYSICS, 1999. - Vol. 41, Is. 1. - P80-86. - ISSN 1063-7834, DOI 10.1134/1.1130733
Примечания : Cited References: 35
Предметные рубрики: ELECTRONIC-STRUCTURE
THIN-FILMS
MAGNETIC-PROPERTIES
RARE-EARTH
MAGNETOOPTICAL PROPERTIES
MNBI FILMS
STABILITY
GD
Аннотация: A study is reported of the structural, magnetic, and magneto-optic properties of Mn/Dy/Bi films obtained by multilayer technology. The maximum Kerr rotation angle in such films is shown to be theta(k) = 2.25 degrees. Possible reasons for such a large Kerr effect enhancement are considered, namely, an increase in the 6p - 3d transition probability caused by symmetry distortion, polarization of the Bi6p band, and a change in the density of states near the Fermi level. The latter reason has been analyzed by simulating the electronic structure of Mn/Dy/Bi through superposition of Dy levels on the MnBi band structure. This approach has revealed possible additional transitions which may be induced by the presence of a Dy buffer and could contribute to the Kerr magneto-optic effect. (C) 1999 American Institute of Physics. [S1063=7834(99)02001-8].
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9.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Varganov S. A., Avramov P. V., Ovchinnikov S. G.
Заглавие : Ab initio calculations of endo- and exohedral C-60 fullerene complexes with Li+ ion and the endohedral C-60 fullerene complex with Li-2 dimer
Место публикации : Phys. Solid State: AMER INST PHYSICS, 2000. - Vol. 42, Is. 2. - P388-392. - ISSN 1063-7834, DOI 10.1134/1.1131218
Примечания : Cited References: 16
Предметные рубрики: ELECTRONIC-STRUCTURE
ENERGIES
C60
Аннотация: The results of ab initio Hartree-Fock calculations of endo- and exohedral C-60 fullerene complexes with the Li+ ion and Li-2 dimer are presented. The coordination of the Li+ ion and the Li-2 dimer in the endohedral complexes and the coordination of Li+ ion in the exohedral complex of C-60 fullerene are determined by the geometry optimization using the 3-21G basis set. In the endohedral Li+C60 complex, the Li+ ion is displaced from the center of the C-60 cage to the centers of carbon hexa- and pentagons by 0.12 nm. In the Li-2 dimer encapsulated inside the C-60 cage, the distance between the lithium atoms is 0.02 nm longer than that in the free molecule. The calculated total and partial one-electron densities of states of C-60 fullerene are in good agreement with the experimental photoelectron and X-ray emission spectra. Analysis of one-electron density of states of the endohedral Li+@C-60 complex indicates an ionic bonding between the Li atoms and the C-60 fullerene. In the Li+C60 and Li+@C-60 complexes, there is a strong electrostatic interaction between the Li+ ion and the fullerene. (C) 2000 MAIK "Nauka/Interperiodica".
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : OVCHINNIKOV S. G.
Заглавие : EFFECT OF SUBSTITUTIONAL IMPURITY SPECIES ON THE SUPPRESSION OF MAGNETIC-PROPERTIES OF WEAKLY DOPED COPPER OXIDES
Место публикации : Fiz. Tverd. Tela: MEZHDUNARODNAYA KNIGA, 1994. - Vol. 36, Is. 5. - P1307-1310. - ISSN 0367-3294
Примечания : Cited References: 16
Предметные рубрики: ELECTRONIC-STRUCTURE
SUPERCONDUCTIVITY
LA2CUO4
EXCITATIONS
SPECTRA
WOS
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ovchinnikov S. G., Rudenko V. V., Kazak N. V., Edelman I. S., Gavrichkov V. A.
Заглавие : Weak antiferromagnet iron borate FeBO3. classical object for magnetism and the state of the art
Коллективы : Russian Science FoundationRussian Science Foundation (RSF) [18-12-00022]
Место публикации : J. Exp. Theor. Phys. - 2020. - Vol. 131, Is. 1. - P.177-188. - ISSN 1063-7761, DOI 10.1134/S106377612007016X. - ISSN 1090-6509(eISSN)
Примечания : Cited References: 74. - This work was supported by the Russian Science Foundation, project no. 18-12-00022
Предметные рубрики: ELECTRONIC-STRUCTURE
TRANSITION
RESONANCE
FERROMAGNETISM
DEPENDENCE
Аннотация: The simple lattice and magnetic structure, the high Neel temperature, the narrow antiferromagnetic resonance line of FeBO3, and the narrow electron paramagnetic resonance line of its isostructural diamagnetic analogs MBO3:Fe3+(M = Ga, In, Sc, Lu) make iron borate unique for investigations and applications. Iron borate is a model crystal for numerous experimental and theoretical studies, including spin crossovers and metallization at megabar pressures and many-electron effects in optics and X-ray spectroscopy. The recent works dealing with the investigation of the properties of FeBO(3)are reviewed.
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Komarov K. K., Dzebisashvili D. M.
Заглавие : Effect of Coulomb repulsion on the London penetration depth in cuprate superconductors
Коллективы : Russian Foundation for Basic ResearchRussian Foundation for Basic Research (RFBR) [18-02-00837, 20-32-70059]; Government of Krasnoyarsk Region; Krasnoyarsk Regional Science and Technology Support Fund [18-42-240014, 18-42-243002]; Council for Grants of the President of the Russian Federation [MK-1641.2020.2]
Место публикации : Phys. Scr. - 2020. - Vol. 95, Is. 6. - Ст.065806. - ISSN 0031-8949, DOI 10.1088/1402-4896/ab8163. - ISSN 1402-4896(eISSN)
Примечания : Cited References: 57. - The work was financially supported by the Russian Foundation for Basic Research (project #18-02-00837, #20-32-70059), the Government of Krasnoyarsk Region, the Krasnoyarsk Regional Science and Technology Support Fund (projects: #18-42-240014 'One-orbit effective model of an ensemble of spin-polaron quasiparticles in the problem of describing the intermediate state and pseudogap behavior of cuprate superconductors' and #18-42-243002 'Manifestation of spin-nematic correlations in spectral characteristics of electronic structure and their influence on practical properties of cuprate superconductors'). The work of KKK was supported by the Council for Grants of the President of the Russian Federation (project MK-1641.2020.2).
Предметные рубрики: ELECTRONIC-STRUCTURE
SUPERFLUID DENSITY
QUASI-PARTICLES
2-BAND MODEL
Аннотация: We study the effect of Coulomb repulsion between oxygen holes on the London penetration depth λ based on the concept of spin-polaron nature of Fermi quasiparticles in cuprates superconductors. It is shown that for the generally accepted values of the parameters of the spin-fermion model, taking into account the Coulomb interaction, both the one-site Hubbard U p and interaction between holes on the next-nearest-neighbor oxygen ions V 2, allows one to achieve a much better agreement of the calculated temperature dependencies of the value λ −2 with the experimental data in La2−x Sr x CuO4 in a wide range around optimal doping.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Sorokin P. B., Ovchinnikov S. G., Avramov P. V., Chernozatonskii L.A., Fedorov D.G.
Заглавие : Atypical quantum confinement effect in silicon nanowires
Место публикации : J. Phys. Chem. A. - WASHINGTON: AMER CHEMICAL SOC, 2008. - Vol. 112, Is. 40. - С. 9955-9964. - OCT 9. - ISSN 1089-5639, DOI 10.1021/jp805069b
Примечания : Cited Reference Count: 25. - Гранты: This work was in part partially supported by a CREST (Core Research for Evolutional Science and Technology) grant in the Area of High Performance Computing for Multiscale and Multiphysics Phenomena from the Japan Science and Technology Agency (JST) as well as by Russian Fund of Basic Researches (grant 08-02-01096) (L.A.C.). P.V.A. acknowledges the encouragement of Dr. Keiji Morokuma, Research Leader at Fukui Institute for Fundamental Chemistry. The geometry of all presented structures was visualized by ChemCraft software.SUP25/SUP L.A.C. acknowledges I. V. Stankevich for help and fruitful discussions. P.B.S. is grateful to the Joint Supercomputer Center of the Russian Academy of Sciences for access to a cluster computer for quantum-chemical calculations.Финансирующая организация: Japan Science and Technology Agency (JST); Russian Fund of Basic Researches [08-02-01096]
Предметные рубрики: ELECTRONIC-STRUCTURE
OPTICAL-PROPERTIES
SI
DENSITY
WIRES
EXCHANGE
ATOMS
DOTS
Ключевые слова (''Своб.индексиров.''): electric wire--energy gap--gallium alloys--mathematical models--nanostructured materials--nanostructures--nanowires--quantum confinement--quantum electronics--semiconductor quantum dots--silicon--ami methods--band gaps--blue shifts--dinger equations--linear junctions--monotonic decreases--quantum confinement effects--quantum dots--semiempirical--silicon nanowires--system sizes--theoretical models--nanocrystalline silicon--nanowire--quantum dot--silicon--article--chemistry--electron--quantum theory--electrons--nanowires--quantum dots--quantum theory--silicon
Аннотация: The quantum confinement effect (QCE) of linear junctions of silicon icosahedral quantum dots (IQD) and pentagonal nanowires (PNW) was studied using DFT and semiempirical AM1 methods. The formation of complex IQD/PNW structures leads to the localization of the HOMO and LUMO on different parts of the system and to a pronounced blue shift of the band gap; the typical QCE with a monotonic decrease of the band gap upon the system size breaks down. A simple one-electron one-dimensional Schrodinger equation model is proposed for the description and explanation of the unconventional quantum confinement behavior of silicon IQD/PNW systems. On the basis of the theoretical models, the experimentally discovered deviations from the typical QCE for nanocrystalline silicon are explained.
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Mitskan V. A., Korovushkin M. M., Dzebisashvili D. M.
Заглавие : Implementation of the concept of spin polaron in cuprate superconductors within the diagram technique
Место публикации : JETP Letters. - 2021. - Vol. 114, Is. 5. - P.289-295. - ISSN 0021-3640, DOI 10.1134/S0021364021170094. - ISSN 1090-6487(eISSN)
Примечания : Cited References: 43. - This work was supported by the Russian Foundation for Basic Research, project nos. 18-02-00837 and 20-32-70059
Предметные рубрики: ELECTRONIC-STRUCTURE
ELEMENTARY EXCITATIONS
QUASI-PARTICLES
Аннотация: The spectral properties of an ensemble of spin-polaron quasiparticles have been studied within the spin–fermion model of cuprate superconductors using the method combining the Feynman diagram technique and the diagram technique for spin operators. It has been shown that strong spin–charge coupling results in the formation of the lower spin-polaron band separated by a wide energy gap from the band of bare holes. It has been shown that the spin-polaron band has a local minimum near the (π/2, π/2) point of the Brillouin zone. A class of diagrams for the self-energy part that have a fundamental significance for the description of the main features of the spin-polaron spectrum has been determined.
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Xing, Gongcheng, Feng, Yuxin, Gao, Zhiyu, Tao, Mengxuan, Wang, Hongquan, Wei, Y.i., Molokeev M. S., Li, Guogang
Заглавие : A novel red-emitting La2CaHfO6:Mn4+ phosphor based on double perovskite structure for pc-WLEDs lighting
Место публикации : CrystEngComm. - 2019. - Vol. 21, Is. 23. - P.3605-3612. - ISSN 1466-8033, DOI 10.1039/c9ce00556k
Примечания : Cited References: 47. - This work is financially supported by the National Natural Science Foundation of China (NSFC No. 51672259).
Предметные рубрики: LUMINESCENCE PROPERTIES
ELECTRONIC-STRUCTURE
OPTICAL-PROPERTIES
SITE
Аннотация: Non-rare earth doped oxides with red emission are one of the current research hotspots for achieving the warm white light range in the phosphor converted white light emitting diodes (pc-WLEDs) field. In the current work, a novel Mn4+-activated La2CaHfO6 red phosphor is reported for the first time and its crystal structure is analyzed by Rietveld refinement. The photoluminescent properties of La2CaHfO6:Mn4+ are investigated in detail with the help of diffuse refletance spectroscopy, photoluminescence spectroscopy, and temperature-dependent PL spectroscopy. Based on the diffuse refletance spectra, the calculated optical band gap for La2CaHfO6 is 4.9 eV, indicating that La2CaHfO6 could be a suitable host for activators' doping. Under 380 nm near-ultraviolet (n-UV) light excitation, the as-prepared La2CaHfO6:Mn4+ displays intense red emission centered at 693 nm. Through an accurate calculation of Dq/B (2.47) and nephelauxetic effect β1 (0.949), the origination of strong crystal field (CF) and deep-red emission is demonstrated. By combining the representative La2CaHfO6:0.002Mn4+, blue BAM:Eu2+, and green (Ba,Sr)2SiO4:Eu2+ phosphors with a 380 nm UV chip to fabricate the pc-WLEDs device, a white light is obtained with low correlated color temperature (CCT = 5165 K) and high color rendering index (Ra = 87.8), demonstrating that the as-prepared La2CaHfO6:Mn4+ phosphors can be used as red-emitting candidate in pc-WLEDs lighting.
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Togushova, Yu. N., Shestakov V. A., Korshunov M. M.
Заглавие : Impurity-induced smearing of the spin resonance peak in Fe-based superconductors
Коллективы : RFBR [13-02-01395]; President Grant for Government Support of the Leading Scientific Schools of the Russian Federation [NSh-2886.2014.2]; Ministry of education and science of Russia [GF-2, SFU]
Место публикации : J. Low Temp. Phys.: Springer/Plenum Publishers, 2016. - Vol. 185, Is. 5-6. - P.481-487. - ISSN 0022-2291, DOI 10.1007/s10909-016-1577-x. - ISSN 1573-7357(eISSN)
Примечания : Cited References:25. - We acknowledge partial support by the RFBR (Grant 13-02-01395), President Grant for Government Support of the Leading Scientific Schools of the Russian Federation (NSh-2886.2014.2), and The Ministry of education and science of Russia (GF-2, SFU).
Предметные рубрики: HIGH-TEMPERATURE SUPERCONDUCTIVITY
ELECTRONIC-STRUCTURE
IRON
Ключевые слова (''Своб.индексиров.''): fe-based superconductors--spin resonance peak--spin-orbit coupling--impurity scattering
Аннотация: The spin resonance peak in the iron-based superconductors is observed in inelastic neutron scattering experiments and agrees well with predicted results for the extended s-wave (s±) gap symmetry. On the basis of four-band and three-orbital tight-binding models we study the effect of nonmagnetic disorder on the resonance peak. Spin susceptibility is calculated in the random-phase approximation with the renormalization of the quasiparticle self-energy due to the impurity scattering in the static Born approximation. We find that the spin resonance becomes broader with the increase of disorder and its energy shifts to higher frequencies. For the same amount of disorder the spin response in the s± state is still distinct from that of the s++ state.
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ovchinnikov S. G.
Заглавие : Сomparison between the band structures of La2CuO4 and Nd2CuO4
Место публикации : Zhurnal Eksperimentalnoi Teor. Fiz.: MEZHDUNARODNAYA KNIGA, 1992. - Vol. 102, Is. 1. - P.127-131. - ISSN 0044-4510
Примечания : Cited References: 6
Предметные рубрики: ELECTRONIC-STRUCTURE
Аннотация: The band structure of quasiparticles in undoped La2CuO4 and Nd2CuO4 dielectric compounds is calculated involving the strong electron correlations in the generalized tight-binding method. In both compounds the dielectric gap is determined mainly by the charge-transfer processes. The reduction of the gap during the La-to-Nd transition is described by decreasing the parameter delta=epsilon(p)-epsilon(d) under the fixed other parameters of the theory, epsilon(p) and epsilon(d) being the energies of the single-particle states of p- and d-holes.
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Krinitsin, Pavel, Yelisseyev, Alexander, Jiang, Xingxing, Isaenko, Lyudmila, Molokeev M. S., Lin, Zheshuai, Pugachev, Alexey
Заглавие : Growth, Structure, and Optical Properties of Nonlinear LiGa0.55In0.45Te2 Single Crystals
Коллективы : Russian Foundation of Basic Research [15-02-03408a, 17-45-540775r_a, 17-52-53031]; national scientific foundations of China [11474292, 51702330, 11611530680, 91622118, 91622124]; special foundation of the director of Technical Institute of Physics and Chemistry (TIPC); China "863" project [2015AA034203]; Youth Innovation Promotion Association, CAS [2017035]; [0330-2016-0008]
Место публикации : Cryst. Growth Des. - 2019. - Vol. 19, Is. 3. - P.1805-1814. - ISSN 1528-7483, DOI 10.1021/acs.cgd.8b01788. - ISSN 1528-7505(eISSN)
Примечания : Cited References: 43. - This work was supported by state assignment project #0330-2016-0008 and partially by the Russian Foundation of Basic Research (Grant Nos. 15-02-03408a, 17-45-540775r_a, and 17-52-53031), national scientific foundations of China (Grant Nos. 11474292, 51702330, 11611530680, 91622118, and 91622124), the special foundation of the director of Technical Institute of Physics and Chemistry (TIPC), the China "863" project (No. 2015AA034203) and the Youth Innovation Promotion Association, CAS (outstanding member for Z.L. and Grant 2017035 for X.J.). Some part of the experiments was performed in the multiple-access center "High-Resolution Spectroscopy of Gases and Condensed Matter" at the IA&E SBRAS (Novosibirsk, Russia). The authors are grateful to N. F. Beisel from the Analytical laboratory of the Nikolaev Institute of Inorganic Chemistry SB RAS for atomic-emission spectral analysis of the studied crystals.
Предметные рубрики: PHASE-MATCHING PROPERTIES
ELECTRONIC-STRUCTURE
MID-IR
Аннотация: In search of new nonlinear optical crystals for the mid-IR range, we grew single crystals of LiGa0.55In0.45Te2 (LGITe) of optical quality; its structure was established, and the spectroscopic properties were studied. LGITe crystallizes in a tetragonal chalcopyrite-like (I4̅2d) structure at 667 ± 5 °C. Crystals are transparent in the 0.76–14.8 μm spectral region with some absorption bands related to OH/H2O and Ge–O vibrations. Analysis of the Tauc plots showed that LGITe is a direct band gap semiconductor with the band gap Eg = 1.837 eV at 300 K. The Raman spectrum for LGITe is very similar to that for LiGaTe2: the most intense band A1 near 120 cm–1 corresponds to the Li–Te vibration. DFT calculations were carried out for the first time to simulate the energy band structure (band gap ∼1.67 eV), density of states (DOS), birefringence (0.049 at 2 μm), and nonlinear susceptibility (d14 = d36 = −48.73 pm/V). For ternary LiInTe2 these parameters are Δn = 0.007 and d14 = d36 = −61.4 pm/V, respectively. The calculated optical properties indicate that LiGa0.55In0.45Te2 is a promising mid-IR nonlinear optical crystal with nonlinear parameters higher than those of LiGaTe2.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Yelisseyev A. P., Molokeev M. S., Jiang, Xingxing, Krinitsin P. G., Isaenko L. I., Lin, Zheshuai
Заглавие : Structure and optical properties of the Li2In2GeSe6 crystal
Коллективы : Russian Foundation of Basic Research [15-02-03408a, 17-45-540775r_a, 17-52-53031]; National Scientific Foundations of China [11474292, 51702330, 11611530680, 91622118, 91622124]; special foundation of the director of Technical Institute of Physics and Chemistry (TIPC); China "863" project [2015AA034203]; Youth Innovation Promotion Association, CAS [2017035]; [0330-2016-0008]
Место публикации : J. Phys. Chem. C. - 2018. - Vol. 122, Is. 30. - P.17413-17422. - ISSN 1932-7447, DOI 10.1021/acs.jpcc.8b02799
Примечания : Cited References: 49. - This work was supported by state assignment project #0330-2016-0008 and partly by the Russian Foundation of Basic Research (grants nos. 15-02-03408a, 17-45-540775r_a, and 17-52-53031), National Scientific Foundations of China (grants 11474292, 51702330, 11611530680, 91622118, and 91622124), the special foundation of the director of Technical Institute of Physics and Chemistry (TIPC), the China "863" project (no. 2015AA034203), and the Youth Innovation Promotion Association, CAS (outstanding member for Z.L. and grant 2017035 for X.J.).
Предметные рубрики: PHASE-MATCHING PROPERTIES
TEMPERATURE-DEPENDENCE
ELECTRONIC-STRUCTURE
Аннотация: Intense search for new nonlinear optical crystals for the mid-infrared region is in progress, and Li-containing quaternary chalcogenides are expected to improve transparency range, stability, phase-matching conditions, and other parameters in comparison with commercially available AgGaS2, AgGaSe2, and ZnGeP2. Single crystals of Li2In2GeSe6 up to 8 mm in size were obtained by the Bridgman- Stockbarger growth technique, and their high quality was confirmed by exciton luminescence. A monoclinic structure and direct band-to-band electronic transitions were established, and the thermal expansion was shown to be virtually isotropic. Defect-related absorption and luminescence were revealed, and the way to lower them was suggested. The electronic structure, density of states, and some optical properties were calculated from the first principles for Li2In2GeSe6. The calculated nonlinear coefficients and rather large birefringence indicate a strong phase-matching ability. These investigations demonstrate that Li2In2GeSe6 is a promising mid-infrared nonlinear optical crystal.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Aplesnin S. S., Romanova O. B., Янушкевич, Казимир Иосифович
Заглавие : Magnetoresistance effect in anion-substituted manganese chalcogenides
Место публикации : Phys. Status Solidi B. - 2015. - Vol. 252, Is. 8. - P.1792-1798. - ISSN 0370, DOI 10.1002/pssb.201451607. - ISSN 15213951 (eISSN)
Примечания : Cited References: 35. - This study was supported by the official assignment no. 114090470016.
Предметные рубрики: MAGNETIC-PROPERTIES
ELECTRONIC-STRUCTURE
SOLID-SOLUTIONS
MnTe
MnSe
CONDUCTIVITY
TRANSITION
Ключевые слова (''Своб.индексиров.''): electron tunneling--magnetic properties--magnetoresistance--semiconductors
Аннотация: The electric and magnetic properties of anion-substituted antiferromagnetic MnSe1-xTex (0.1≤x≤0.4) semiconductors in the 77-700K temperature range and magnetic fields under 1T are studied. In the MnSe1-xTex solid solutions, negative magnetoresistance in the vicinity of the Néel temperature for x=0.1 and for composition with x=0.2 in the paramagnetic range below 270K is revealed. A dependence of the magnetic susceptibility versus the prehistory of the samples is found. The model of localized spin-polarized electrons with the localization radius depending on the magnetic field is proposed for x=0.1. In the paramagnetic range, the negative magnetoresistance and the behavior of magnetic moment are a result of orbital glass formation.
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