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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ruseikina A. V., Grigoriev M. V., Solovyov L. A., Chernyshev V. A., Aleksandrovsky A. S., Krylov A. S., Krylova S. N., Shestakov N. P., Velikanov D. A., Garmonov A. A., Matigorov A. V., Eberle M. A., Schleid T., Safin D. A.
Заглавие : A Challenge toward novel quaternary sulfides SrLnCuS3 (Ln = La, Nd, Tm): Unraveling synthetic pathways, structures and properties
Место публикации : Int. J. Mol. Sci. - 2022. - Vol. 23, Is. 20. - Ст.12438. - ISSN 14220067 (ISSN), DOI 10.3390/ijms232012438
Примечания : Cited References: 62. - The research was funded by the Tyumen Oblast Government, as part of the West-Siberian Interregional Science and Education Center’s project No. 89-DON (3). This work was supported by state assignment of the Ministry of Science and Higher Education of the Russian Federation (Project Reg. No. 720000Φ.99.1.Б385AA13000)
Аннотация: We report on the novel heterometallic quaternary sulfides SrLnCuS3 (Ln = La, Nd, Tm), obtained as both single crystals and powdered samples. The structures of both the single crystal and powdered samples of SrLaCuS3 and SrNdCuS3 belong to the orthorhombic space group Pnma but are of different structural types, while both samples of SrTmCuS3 crystallize in the orthorhombic space group Cmcm with the structural type KZrCuS3. Three-dimensional crystal structures of SrLaCuS3 and SrNdCuS3 are formed from the (Sr/Ln)S7 capped trigonal prisms and CuS4 tetrahedra. In SrLaCuS3, alternating 2D layers are stacked, while the main backbone of the structure of SrNdCuS3 is a polymeric 3D framework [(Sr/Ln)S7]n, strengthened by 1D polymeric chains (CuS4)n with 1D channels, filled by the other Sr2+/Ln3+ cations, which, in turn, form 1D dimeric ribbons. A 3D crystal structure of SrTmCuS3 is constructed from the SrS6 trigonal prisms, TmS6 octahedra and CuS4 tetrahedra. The latter two polyhedra are packed together into 2D layers, which are separated by 1D chains (SrS6)n and 1D free channels. In both crystal structures of SrLaCuS3 obtained in this work, the crystallographic positions of strontium and lanthanum were partially mixed, while only in the structure of SrNdCuS3, solved from the powder X-ray diffraction data, were the crystallographic positions of strontium and neodymium partially mixed. Band gaps of SrLnCuS3 (Ln = La, Nd, Tm) were found to be 1.86, 1.94 and 2.57 eV, respectively. Both SrNdCuS3 and SrTmCuS3 were found to be paramagnetic at 20-300 K, with the experimental magnetic characteristics being in good agreement with the corresponding calculated parameters.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Yelisseyev A., Lobanov S., Molokeev M. S., Zhang S., Pugachev A., Lin Z., Vedenyapin V., Kurus A., Khamoyam A., Isaenko L.
Заглавие : A New Nonlinear Optical Selenide Crystal AgLiGa2Se4 with Good Comprehensive Performance in Mid-Infrared Region
Место публикации : Adv. Opt. Mater. - 2021. - Vol. 9, Is. 5. - Ст.2001856. - ISSN 21951071 (ISSN), DOI 10.1002/adom.202001856
Примечания : Cited References: 32. - Crystal growth and investigation of physical properties were supported by Russian Science Foundation, Russia (#19‐12‐00085). Spectroscopic data were obtained at the Institute of Geology and Mineralogy, Siberian Branch of Russian Academy of Sciences, Russia; Ministry of Science and Higher Education, Russia (performed on a state assignment). The work on first‐principles calculations also supported by National Science Foundation in China (No.51872297) and Fujian Institute of Innovation (FJCXY18010201) in Chinese Academy of Sciences
Аннотация: Mid‐infrared (mid‐IR) nonlinear optical (NLO) crystals are indispensable for the mid‐IR lasers generation with tunable wavelengths from 3 to 20 µm. AgGaSe2 is a commercial mid‐IR NLO crystal with the highest figures of merit, but suffers low laser damage threshold (LDT). To achieve the balance of optical transmission, NLO effect, and LDT, it is proposed to molecularly modify the AgGaSe2 structure by introducing the [LiSe4] tetrahedra, and successfully grow large crystals of a new selenide AgLiGa2Se4. The replacement of half of the heavy Ag+ cations with light Li+ increases the band gap to 2.2 eV (vs. 1.7 eV in AgGaSe2). The LDT value in AgLiGa2Se4 increases five times compared to that in AgGaSe2, while keeping a relatively large NLO susceptibility of 26 pm V−1. Moreover, the thermal expansion coefficients in AgLiGa2Se4 are approximately two times lower in absolute value compared with AgGaSe2, which is beneficial to the large crystal growth. All these advantages would make AgLiGa2Se4 a new promising NLO crystal for mid‐IR laser applications.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Lundin U., Sandalov I., Eriksson O., Johansson B.
Заглавие : Are there two types of f-electrons in Pr-metal?
Коллективы : International Conference on Strongly Correlated Electron Systems
Место публикации : Physica B. - 1999. - Vol. 259-61. - P.231-232. - ISSN 0921-4526, DOI 10.1016/S0921-4526(98)00790-X
Примечания : Cited References: 1
Предметные рубрики:
Ключевые слова (''Своб.индексиров.''): band calculations--hubbard model--f-electrons
Аннотация: We show that in order to properly describe the bonding properties of strongly correlated systems, here demonstrated for praseodymium metal, it is necessary to split the f-electron system into two parts. Using perturbation theory from the atomic limit we show that LDA-based calculations with f-electrons in the core can be considered as the limit of an infinite Hubbard U. Then, the correction to the total energy proportional to 1/U makes the upper f(2)--f(3) intra-atomic transitions (IT) important. Mixing interaction and f-f-hopping delocalize these IT and some of them become populated. These IT give an additional contribution to the cohesive energy. This gain in energy is the reason for the separation of the f-electron system into localized (with reduced spectral weight) and delocalized ones. (C) 1999 Elsevier Science B.V. All rights reserved.
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Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Ivanova D., Fedorova N., Kozak V., Shubin A., Tomilin F. N.
Заглавие : Atomic and electronic structure of MAX-phase Cr2AlC studied by DFT calculations
Коллективы : International workshop on functional MAX-materials, Kirensky Institute of Physics, Siberian Federal Univercity
Место публикации : International workshop on the properties of functional MAX-materials (2nd FunMax): book of abstracts/ org. com. M. Farle [et al.]. - 2021. - P.37
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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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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kuzubov A. A., Kovaleva E. A., Avramov P. V., Kholtobina A. S., Mikhaleva N. S., Kuklin A. V.
Заглавие : Buckminsterfullerene's movability on the Fe(001) surface
Место публикации : J. Magn. Magn. Mater.: Elsevier, 2016. - Vol. 410. - P.41-46. - ISSN 03048853 (ISSN), DOI 10.1016/j.jmmm.2016.03.023
Примечания : Cited References: 32. - This work was supported by the Russian Scientific Fund (Project no. 14-13-00139) and the Foundation for Assistance to Small Innovative Enterprises (FASIE) (Project no. 0011742). The authors would like to thank Institute of Computational Modeling of SB RAS, Krasnoyarsk; Joint Supercomputer Center of RAS, Moscow; Center of Equipment for Joint Use of Siberian Federal University, Krasnoyarsk; ICC of Novosibirsk State University and Siberian Supercomputer Center (SSCC) of SB RAS, Novosibirsk for providing the access to their supercomputers.
Предметные рубрики: Initio molecular-dynamics
Total-energy calculations
Augmented-wave
Ключевые слова (''Своб.индексиров.''): buckminsterfullerene--c60--fe(001)--spintronics--adsorption--relocation--dft
Аннотация: Organic-based spintronics is one of the most fast-developing fields in nanoelectronics. Buckminsterfullerene-based composites are widely investigated due to its unique properties and there is a number of studies concerned with its interfaces with various types of substrates. Ferromagnetic surfaces are of a particular interest for potential spintronics applications. Based on the data reported in literature, we suppose that there are more than one stable structure in C60/Fe(001) composite system. Here we investigate different possible adsorption sites of C60 molecule and reveal the possibility of their coexistence and its influence on the composite properties. © 2016 Elsevier B.V.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Anghel L., Balasoiu M., Ishchenko L. A., Stolyar S. V., Kurkin T. S., Rogachev A. V., Kuklin A. I., Kovalev Yu.S., Raikher Yu.L., Iskhakov R. S., Duca G.
Заглавие : Characterization of bio-synthesized nanoparticles produced by Klebsiella oxytoca
Коллективы : International Workshop on SANS-YuMO User Meeting at the Start-up of Scientific Experiments on the IBR-2M Reactor: Devoted to the 75th Anniversary of Yu M Ostanevich's Birth
Место публикации : Journal of Physics: Conference Series. - 2012. - Vol. 351, Is. 1. - Ст.012005. - P. - ISSN 1742-6588, DOI 10.1088/1742-6596/351/1/012005
Ключевые слова (''Своб.индексиров.''): absorption peaks--biominerals--chemical compositions--exopolysaccharides--ferrihydrites--fitting procedure--ftir spectroscopy--klebsiella oxytoca--model calculations--morphological analysis--radius of gyration--scattering objects--small angle x-ray scattering--structural and morphological properties--structural investigation--uv-vis spectroscopy--water dispersion--water-dispersed--experiments--nanoparticles--polysaccharides--raman spectroscopy--scattering--ultraviolet visible spectroscopy--synthesis (chemical)
Аннотация: Structural and morphological properties of biogenic ferrihydrite nanoparticles produced by bacteria Klebsiella oxytoca are investigated. The stability of water dispersions of biomineral particles produced by Klebsiella oxytoca was monitored by UV-Vis spectroscopy. Their chemical composition was determined by FT-IR spectroscopy. The vibrational spectra of biogenic ferrihydrite nanoparticles revealed typical absorption peaks of exopolysaccharides. Morphological analysis based on Raman spectroscopy indicated the presence of exopolysaccharides on the surface as well as inside the pores of the ferrihydrite nanoparticles. Structural investigations of ultrasonic assisted samples of different concentration of water dispersed particles were performed using small angle X-ray scattering analysis. Model calculations and fitting procedures revealed scattering objects of an elongated shape with 6.73В±0.16 nm radius of gyration. В© Published under licence by IOP Publishing Ltd.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kovaleva E. A., Kuzubov A. A., Avramov P. V., Kuklin A. V., Mikhaleva N. S., Krasnov P. O.
Заглавие : Characterization of LSMO/C60 spinterface by first-principle calculations
Место публикации : Org. Electron.: Phys. Mater. Appl.: Elsevier, 2016. - Vol. 37. - P.55-60. - ISSN 15661199 (ISSN), DOI 10.1016/j.orgel.2016.06.021
Примечания : Cited References: 40. - This work was supported by the Russian Scientific Fund (Project No. 14-13-00139). The authors would like to thank Institute of Computational Modeling of SB RAS, Krasnoyarsk; Joint Supercomputer Center of RAS, Moscow; Center of Equipment for Joint Use of Siberian Federal University, Krasnoyarsk; ICC of Novosibirsk State University and Siberian Supercomputer Center (SSCC) of SB RAS, Novosibirsk for providing the access to their supercomputers.
Предметные рубрики: INITIO MOLECULAR-DYNAMICS
TOTAL-ENERGY CALCULATIONS
AUGMENTED-WAVE METHOD
ORGANIC SPIN-VALVES
BASIS-SET
SEMICONDUCTORS
INJECTION
SPINTRONICS
TEMPERATURE
ALGORITHM
Ключевые слова (''Своб.индексиров.''): c60--lsmo--spinterface--dft--magnetic ordering
Аннотация: Spinterface between fullerene C60 and La0 7Sr0 3MnO3 (LSMO) was studied by means of density functional theory. Co-existence of many different configurations was shown, and probabilities of their appearance were estimated. Dependence of composite properties on configuration and temperature was also investigated. Key role of transition metal atoms in both binding between composite compartments and magnetic ordering in C60 molecule was discussed. The latter was suggested to be responsible for spin-polarized charge transport while overall magnetic moment of fullerene molecule is relatively small. © 2016 Elsevier B.V.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Churilov G. N., Fedorov A. S., Novikov P. V.
Заглавие : Fullerene C-60 formation in partially ionized carbon vapor
Разночтения заглавия :авие SCOPUS: Fullerene C60 formation in partially ionized carbon vapor
Место публикации : JETP Letters. - 2002. - Vol. 76, Is. 8. - P.522-526. - ISSN 0021-3640, DOI 10.1134/1.1533779
Примечания : Cited References: 15
Предметные рубрики: TOTAL-ENERGY CALCULATIONS
WAVE BASIS-SET
CLUSTERS
GROWTH
Аннотация: The assembling rate of a fullerene C-60 molecule has been theoretically studied as a function of electron concentration and temperature in partially ionized carbon vapor. For C-60 formation via one or two intermediate stages of cluster collisions, it has been shown that there is a region of plasma parameters (the temperature and electron concentration) in which fullerene C-60 is formed more efficiently. The C-60 formation rate versus temperature and electron concentration relationships have been found to correlate with the trends in the collision cross-section of carbon clusters as functions of these parameters. (C) 2002 MAIK "Nauka/Interperiodica".
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Nasluzov V. A., Rivanenkov V. V., Gordienko A. B., Neyman K. M., Birkenheuer U., Rosch N.
Заглавие : Cluster embedding in an elastic polarizable environment: Density functional study of Pd atoms adsorbed at oxygen vacancies of MgO(001)
Место публикации : J. Chem. Phys.: AMER INST PHYSICS, 2001. - Vol. 115, Is. 17. - P8157-8171. - ISSN 0021-9606, DOI 10.1063/1.1407001
Примечания : Cited References: 88
Предметные рубрики: TRANSITION-METAL ATOMS
AB-INITIO
OXIDE SURFACES
ELECTRONIC-PROPERTIES
ENERGY CALCULATIONS
MOLECULAR-DYNAMICS
MOTT-LITTLETON
MADELUNG FIELD
IONIC-CRYSTAL
MGO
Ключевые слова (''Своб.индексиров.''): atoms--binding energy--computer simulation--electron energy levels--electronic structure--magnesia--oxygen--palladium--polarization--probability density function--quantum theory--relaxation processes--charged defects--cluster embedding--elastic polarizable environment--electron affinity--oxygen vacancies--adsorption
Аннотация: Adsorption complexes of palladium atoms on F-s, F-s(+), F-s(2+), and O2- centers of MgO(001) surface have been investigated with a gradient-corrected (Becke-Perdew) density functional method applied to embedded cluster models. This study presents the first application of a self-consistent hybrid quantum mechanical/molecular mechanical embedding approach where the defect-induced distortions are treated variationally and the environment is allowed to react on perturbations of a reference configuration describing the regular surface. The cluster models are embedded in an elastic polarizable environment which is described at the atomistic level using a shell model treatment of ionic polarizabilities. The frontier region that separates the quantum mechanical cluster and the classical environment is represented by pseudopotential centers without basis functions. Accounting in this way for the relaxation of the electronic structure of the adsorption complex results in energy corrections of 1.9 and 5.3 eV for electron affinities of the charged defects F-s(+) and F-s(2+), respectively, as compared to models with a bulk-terminated geometry. The relaxation increases the stability of the adsorption complex Pd/F-s by 0.4 eV and decreases the stability of the complex Pd/F-s(2+) by 1.0 eV, but it only weakly affects the binding energy of Pd/F-s(+). The calculations provide no indication that the metal species is oxidized, not even for the most electron deficient complex Pd/F-s(2+). The binding energy of the complex Pd/O2- is calculated at -1.4 eV, that of the complex Pd/F-s(2+) at -1.3 eV. The complexes Pd/F-s and Pd/F-s(+) exhibit notably higher binding energies, -2.5 and -4.0 eV, respectively; in these complexes, a covalent polar adsorption bond is formed, accompanied by donation of electronic density to the Pd 5s orbital. (C) 2001 American Institute of Physics.
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kuzubov A. A., Kovaleva E. A., Avramov P. V., Kuklin A. V., Mikhaleva N. S., Tomilin F. N., Sakai S., Entani S., Matsumoto Y., Naramoto H.
Заглавие : Contact-induced spin polarization in BNNT(CNT)/TM (TM=Co, Ni) nanocomposites
Коллективы : Russian Scientific Fund [14-13-00139]
Место публикации : J. Appl. Phys.: American Institute of Physics, 2014. - Vol. 116, Is. 8. - Ст.084309. - ISSN 0021-8979, DOI 10.1063/1.4894157. - ISSN 1089-7550
Примечания : Cited References: 21. - This work was supported by the Russian Scientific Fund, Project No. 14-13-00139. The authors would like to thank Institute of Computational Modelling of SB RAS, Krasnoyarsk; Joint Supercomputer Center of RAS, Moscow; the HPC Research Department and Center of Equipment for Joint Use of Siberian Federal University, Krasnoyarsk; Siberian Supercomputer Center (SSCC) of SB RAS, Novosibirsk; and Laboratory of Parallel Information Technologies 21 of Research Computing Center of Moscow State University (the SKIF MSU "Chebyshev" system) for providing the access to their supercomputers.
Предметные рубрики: TOTAL-ENERGY CALCULATIONS
HEXAGONAL BORON-NITRIDE
WAVE BASIS-SET
AB-INITIO
PSEUDOPOTENTIALS
DISPERSION
NANOTUBE
NI(111)
Аннотация: The interaction between carbon and BN nanotubes (NT) and transition metal Co and Ni supports was studied using electronic structure calculations. Several configurations of interfaces were considered, and the most stable ones were used for electronic structure analysis. All NT/Co interfaces were found to be more energetically favorable than NT/Ni, and conductive carbon nanotubes demonstrate slightly stronger bonding than semiconducting ones. The presence of contact-induced spin polarization was established for all nanocomposites. It was found that the contact-induced polarization of BNNT leads to the appearance of local conductivity in the vicinity of the interface while the rest of the nanotube lattice remains to be insulating. (c) 2014 AIP Publishing LLC.
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Sofronova S. N., Moshkina E. M., Nazarenko I. I., Seryotkin Yu. V., Nepijko S. A., Ksenofontov V., Medjanik K., Veligzhanin A. A., Bezmaternykh L. N.
Заглавие : Crystal growth, structure, magnetic properties and theoretical exchange interaction calculations of Cu2MnBO5
Место публикации : J. Magn. Magn. Mater.: Elsevier, 2016. - Vol. 420. - P.309-316. - ISSN 03048853 (ISSN), DOI 10.1016/j.jmmm.2016.07.019
Примечания : Cited References: 35. - X-ray diffraction experiment was carried out at the Centre on Molecular Design and Ecologically Safe Technologies at the Novosibirsk State University. The reported study was funded by Russian Foundation for Basic Research (RFBR) and Government of Krasnoyarsk Territory according to the research project No. 16-42-243028.
Предметные рубрики: SPIN-GLASS BEHAVIOR
SINGLE-CRYSTALS
SUPEREXCHANGE INTERACTIONS
LUDWIGITE
DIELECTRICS
CO3B2O6NI3B2O6
WARWICKITES
FE3O2BO3
IFEFFIT
NI3B2O6
Ключевые слова (''Своб.индексиров.''): oxyborates--ludwigites--xmcd--exafs--magnetism
Аннотация: Single crystals of ludwigite Cu2MnBO5 were synthesized by flux growth technique. The detailed structural and magnetic characterizations of the synthesized samples have been carried out. The cations composition of the studied crystal was determined using X-ray diffraction and EXAFS technique, the resulting composition differ from the content of the initial Mn2O3–CuO components of the flux. Magnetic susceptibility measurements and the calculations of the exchange integrals in frameworks of indirect coupling model revealed that monoclinic distortions strongly affect exchange interactions and appearance of magnetic ordering phase at the temperature T=93 K. The hypothesis of the existence of several magnetic subsystems was supposed. © 2016 Elsevier B.V.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Avramov P. V., Kuzubov A. A., Fedorov A. S., Sorokin P. B., Tomilin F. N., Maeda Y.
Заглавие : Density-functional theory study of the electronic structure of thin Si/SiO2 quantum nanodots and nanowires
Место публикации : Phys. Rev. B: AMERICAN PHYSICAL SOC, 2007. - Vol. 75, Is. 20. - Ст.205427. - ISSN 1098-0121, DOI 10.1103/PhysRevB.75.205427
Примечания : Cited References: 63
Предметные рубрики: ERBIUM ION LUMINESCENCE
TOTAL-ENERGY CALCULATIONS
WAVE BASIS-SET
POROUS SILICON
OPTICAL-PROPERTIES
OXIDIZED SI
SEMICONDUCTOR NANOWIRES
PHASE-TRANSFORMATIONS
NANOCRYSTALS
CONFINEMENT
Аннотация: The atomic and electronic structures of a set of proposed pentagonal thin (1.6 nm in diameter) silicon/silica quantum nanodots (QDs) and nanowires (NWs) with narrow interface, as well as parent metastable silicon structures (1.2 nm in diameter), were studied using cluster B3LYP/6-31G(*) and periodic boundary condition (PBC) plane-wave (PW) pseudopotential (PP) local-density approximation methods. The total density of states (TDOS) of the smallest quasispherical QD (Si-85) corresponds well to the PBC PW PP LDA TDOS of the crystalline silicon. The elongated SiQDs and SiNWs demonstrate the metallic nature of the electronic structure. The surface oxidized layer opens the band gap in the TDOS of the Si/SiO2 species. The top of the valence band and the bottom of conduction band of the particles are formed by the silicon core derived states. The theoretical band gap width is determined by the length of the Si/SiO2 clusters and describes the size confinement effect in the experimental photoluminescence spectra of the silica embedded nanocrystalline silicon with high accuracy.
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Slyusarenko N. V., Yushina I. D., Slyusareva E. A., Golovkina E. V., Krylova S. N., Vtyurin A. N., Krylov A. S.
Заглавие : Determination of the pore direction in a crystalline metal-organic framework by Raman spectroscopy and periodic calculations based on the electron density functional theory
Колич.характеристики :10 с
Место публикации : Optoelectron. Instrum. Data Process. - 2023. - Vol. 59, Is. 6. - P.693-702. - ISSN 87566990 (ISSN), DOI 10.3103/S8756699023060134. - ISSN 19347944 (eISSN)
Примечания : Cited References: 32. - This work was supported by the Russian Foundation for Basic Research (Russian Center of Scientific Information), project no. 21-52-12018We are grateful to Dr. Irena Senkovska for the presented DUT-8 (Ni, Co) samples
Аннотация: A method for the determination of pore orientation in metal-organic framework structures by polarized Raman spectra is proposed. The method involves sensitivity of the line intensity of Raman scattering to the geometry of propagation in a crystal. The operability of the method is shown by DUT-8 (Ni, Co) crystals. The obtained results are interpreted based on analysis of symmetry and direction of vibrations within periodic calculations of the electron density functional theory. The simultaneous approach allowed us to describe the vibrations and to find the principal crystal orientation collinear to the pore direction. The information on the pore orientation is necessary for problems of adsorption and design of complex multicomponent materials based on metal-organic framework.
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kuzubov A. A., Kovaleva E. A., Popova M. I., Kholtobina A. S., Mikhaleva N. S., Visotin M. A., Fedorov A. S.
Заглавие : DFT investigation of electronic structures and magnetic properties of halides family MeHal3 (Me=Ti, Mo,Zr,Nb, Ru, Hal=Cl,Br,I) one dimensional structures
Коллективы : Euro-Asian Symposium "Trends in MAGnetism", "Trends in MAGnetism", Euro-Asian Symposium, Институт физики им. Л.В. Киренского Сибирского отделения РАН , Russian Science Foundation [16-13-00060]; Russian Foundation for Basic Research [RFBR 16-32-60003 mol_a_dk]
Место публикации : J. Magn. Magn. Mater.: Elsevier Science, 2017. - Vol. 440: EURO-Asian Symposium on Trends in Magnetism (EASTMAG) (AUG 15-19, 2016, Siberian Fed Univ, Krasnoyarsk, RUSSIA). - P.93-96. - ISSN 0304-8853, DOI 10.1016/j.jmmm.2016.12.054. - ISSN 1873-4766(eISSN)
Примечания : Cited References:16. - This work was supported by the Russian Science Foundation, Project no. 16-13-00060. N.S.M. thanks the Russian Foundation for Basic Research, project RFBR 16-32-60003 mol_a_dk, for the financial support of ZrIINF3/INF, TiIINF3/INF and NbIINF3/INF electronic structure calculations
Предметные рубрики: INITIO MOLECULAR-DYNAMICS
TOTAL-ENERGY CALCULATIONS
AUGMENTED-WAVE
Ключевые слова (''Своб.индексиров.''): transition metal trihalides--magnetic properties--thermoelectric--conversion--density functional theory
Аннотация: Using DFT GGA calculations, electronic structure and magnetic properties of wide family of transition metal trihalides (TMHal3) (Zr, Ti and Nb iodides, Mo, Ru, Ti and Zr bromides and Ti or Zr chlorides) are investigated. These structures consist of transition metal atoms chains surrounded by halides atoms. Chains are connected to each other by weak interactions. All TMHal3 compounds were found to be conductive along chain axis except of MoBr3 which is indirect gap semiconductor. It was shown that NbI3 and MoBr3 have large magnetic moments on metal atoms (1.17 and 1.81 µB, respectively) but other TMHal3 materials have small or zero magnetic moments. For all structures ferromagnetic and anti-ferromagnetic phases have almost the same energies. The causes of these properties are debated.
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Draganyuk O. N., Zamkova N. G., Zhandun V. S.
Заглавие : Effect of substitution of Mn and Ga atoms by Fe atom in the Mn2GaC MAX phase
Место публикации : J. Magn. Magn. Mater. - 2022. - Vol. 563. - Ст.169860. - ISSN 03048853 (ISSN), DOI 10.1016/j.jmmm.2022.169860
Примечания : Cited References: 40. - The reported study was funded by Russian Foundation for Basic Research, Government of Krasnoyarsk Territory, Krasnoyarsk Regional Fund of Science to the research project № 20-42-240004: “The effect of the composition, pressure, and dimension on the magnetic, electronic, optical, and elastic properties of the magnetic M n+1 AX n (M = Cr, Mn; Fe, A = Al, Ga, Si, Ge, P, In; X = C, N; n = 1-3) MAX-phases”. The calculations were performed with the computer resources of “Complex modeling and data processing research installations of mega-class” SRC “Kurchatovsky Institute” ( http://ckp.urcki.ru ). The ternary phase diagrams for the calculation of formation enthalpies were taken from Materials Project ( https://materialsproject.org ) and OQMD ( https://oqmd.org/ ) databases
Аннотация: The magnetic properties of ordered and disordered MAX-phase Mn2-xFe2xGaC and Mn2Ga1-xFexC (x = 12.5, 25, and 50 at.%) have been studied within DFT-GGA. The investigation of phase stability of M2AX phases is performed by comparing the total energy of MAX phases to that of the set of competitive phases for calculation of the phase formation enthalpy. At the small concentration of Fe atoms (x = 12.5 %) compound remains stable. We have found that introducing Fe atom at A-site leads to the forming of ferromagnetic phase with large magnetic moments on magnetic atoms and magnetization. Through detailed group-theoretical analysis we have obtained that only ferromagnetic ordering is possible when Fe atom ordering over Ga sites. The study of exchange constants shows that the out-of-plane Fe-Mn exchange gives the main contribution in appearance of ferromagnetic phase. The temperature dependences of magnetization reveal the increase of Curie temperature in Mn2GaC with Fe atom incorporated into Ga-site.
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Draganyuk O. N., Zhandun V. S., Zamkova N. G.
Заглавие : Effect of the Local Environment on the Magnetic Properties of Mn3Si: Hybrid Ab Initio and Model Study
Место публикации : Phys. Status Solidi B. - 2019. - Vol. 256, Is. 12. - Ст.1900228. - ISSN 03701972 (ISSN), DOI 10.1002/pssb.201900228
Примечания : Cited References: 34. - The reported study was funded by Russian Foundation for Basic Research, Government of Krasnoyarsk Territory, Krasnoyarsk Regional Fund of Science to the research Project No. 18‐42‐243019: “First‐principles studies of the polarization, magnetic, electronic, and magnetoelectric properties of functional compounds with a spinel structure containing 3d and 4f ions.”
Аннотация: The effect of the local environment on the formation of magnetic moments on Mn atoms in manganese silicide Mn3Si is studied by the combination of ab initio calculations and the model analysis. The suggested approach is related to the self-consistent mapping of the results of ab initio calculations to a multiorbital model. The model analysis allows to reveal the role played by the local environment of the transition metal atoms on the magnetic moments formation. It is found that the formation of the magnetic moment is controlled rather by hopping parameters between Mn atoms, not by the number of Mn–Si nearest neighbors. Particularly, the formation of magnetic moment on MnI atom is mainly controlled by the hopping parameter between nearest Mn atoms, while the magnetic moment on MnII atom is primarily determined by the hoppings between next-nearest Mn atoms. The obtained phase diagrams of the magnetic state show the presence of a sharp boundary with respect to the hopping between Mn atoms. This opens the opportunity to turn on or turn off the magnetic state by the external impacts. The ab initio calculations of Mn3Si well agree with the results of model consideration and confirm the model conclusions.
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Draganyuk O. N., Zhandun V. S., Zamkova N. G.
Заглавие : Half-metallicity in Fe2MnSi and Mn2FeSi heusler compounds: A comparative ab initio study
Место публикации : Mater. Chem. Phys. - 2021. - Vol. 271. - Ст.124897. - ISSN 02540584 (ISSN), DOI 10.1016/j.matchemphys.2021.124897
Примечания : Cited References: 33. - The reported study was funded by Russian Foundation for Basic Research, Government of Krasnoyarsk Territory, Krasnoyarsk Regional Fund of Science to the research projects No19-42-240016: «Control of structural, magnetic, electronic, and optical properties by pressure and intercalation into functional compounds with a spinel structure containing 3d and 4f ions» and 20-42-240004: “The effect of the composition, pressure, and dimension on the magnetic, electronic, optical, and elastic properties of the magnetic Mn+1AXn (M = Cr, Mn; Fe, A = Al, Ga, Si, Ge, P, In; X = C, N; n = 1–3) MAX-phases”. The calculations were performed with the computer resources of “Complex modeling and data processing research installations of mega-class” SRC “Kurchatovsky Institute” (http://ckp.urcki.ru)
Аннотация: First-principles calculations of the structural, electronic, and magnetic properties of full-Heusler compounds Fe2MnSi and Mn2FeSi in regular L21 and inverse XA structures have been performed using density functional theory (DFT) within generalized gradient approximation (GGA) and SCAN functionals. All compounds indicate half-metallic properties with the minority spin bandgap. The causes for the appearance of half-metallic bandgap and the difference in the electronic and magnetic properties of Heusler compounds were studied and analyzed in terms of the local environment. It is shown, that the half-metallic bandgap determines by the behavior of the t2g-electrons of A- and C-sites atoms. The behavior of the compounds under pressure was also considered. The high sensitivity of the magnetic moments on atoms A, C and the bandgap to pressure is discussed. The transition from regular to inverse structure is predicted at the negative pressure.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Sandalov I. S., Zamkova N. G., Zhandun V. S., Tarasov I. A., Varnakov S. N., Yakovlev I. A., Solovyov L. A., Ovchinnikov S. G.
Заглавие : Effect of electron correlations on the Fe3Si and α- FeSi2 band structure and optical properties
Коллективы : Russian Fund of Basic Research [14002-00186, 13-02-01265]; President of Russia Grants [2886.2014.2, 924.2014.2]
Место публикации : Phys. Rev. B: American Physical Society, 2015. - Vol. 92, Is. 20. - Ст.205129. - ISSN 1098-0121, DOI 10.1103/PhysRevB.92.205129. - ISSN 1550-235X(eISSN)
Примечания : Cited References:69. - The theoretical part of this work was supported by Russian Fund of Basic Research, Grant No. 14002-00186 and the President of Russia Grants No. 2886.2014.2 and No. 924.2014.2 for support of Leading Scientific School. The calculations were performed with the computer resources of NRC "Kurchatov Institute" (ui2.computing.kiae.ru). The experimental work was supported by Russian Fund of Basic Research, Grant No. 13-02-01265. I.S. thanks A. Ruban for useful discussion.
Предметные рубрики: DENSITY-FUNCTIONAL THEORY
TOTAL-ENERGY CALCULATIONS
AUGMENTED-WAVE METHOD
BASIS-SET
METALS
ABSORPTION
EMISSION
SURFACES
ALLOYS
LAYERS
Аннотация: We use the Vienna ab initio simulation package (vasp) for evaluation of the quasiparticle spectra and their spectral weights within Hedin's GW approximation (GWA) for Fe3Si and α-FeSi2 within the non-self-consistent one-shot approximation G0W0 and self-consistent scGWA with the vertex corrections in the particle-hole channel, taken in the form of two-point kernel. As input for G0W0, the band structure and wave functions evaluated within the generalized gradient corrected local-density approximation to density functional theory (GGA) have been used. The spectral weights of quasiparticles in these compounds deviate from unity everywhere and show nonmonotonic behavior in those parts of bands where the delocalized states contribute to their formation. The G0W0 and scGWA spectral weights are the same within 2%–5%. The scGWA shows a general tendency to return G0W0 bands to their GGA positions for the delocalized states, while in the flat bands it flattens even more. Variable angle spectroscopic ellipsometry measurements at T=296 K on grown single-crystalline ∼50-nm-thick films of Fe3Si on n-Si(111) wafer have been performed in the interval of energies ω∼(1.3–5) eV. The comparison of G0W0 and scGW theory with experimental real and imaginary parts of permittivity, refractive index, extinction and absorption coefficients, reflectivity, and electron energy loss function shows that both G0W0 and scGW qualitatively describe experiment correctly, the position of the low-energy peaks is described better by the scGW theory, however, its detailed structure is not observed in the experimental curves. We suggest that the angle-resolved photoemission spectroscopy experiments, which can reveal the fine details of the quasiparticle band structure and spectral weights, could help to understand (i) if the scGWA with this type of vertex correction is sufficiently good for description of these iron silicides and, possibly, (ii) why some features of calculated permittivity are not seen in optical experiments.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zamkova N. G., Zhandun V. S., Ovchinnikov S. G., Sandalov I. S.
Заглавие : Effect of local environment on moment formation in iron silicides
Место публикации : J. Alloys Compd.: Elsevier, 2017. - Vol. 695. - P.1213-1222. - ISSN 09258388 (ISSN), DOI 10.1016/j.jallcom.2016.10.248
Примечания : Cited References: 40. - This work was supported by the Grants of Russian Foundation for Basic Research № 14-02-00186, № 17-02-00161 and by the Grants of Russian Foundation for Basic Research and Government of Krasnoyarsk Territory № 16-42-243035, 16-42-242036. The authors would like to thank AS Shinkorenko for the technical support.
Ключевые слова (''Своб.индексиров.''): ab initio calculations--iron silicides--magnetic properties--multiorbital model--spin-crossover
Аннотация: he effect of local environment on the formation of magnetic moments on Fe atoms in iron silicides is studied by combination of ab initio and model calculations. The suggested model includes all Fe d- and Si p-orbitals, intra-atomic Coulomb interactions, inter-atomic Fe-Fe exchange and hopping of electrons to nearest and next nearest neighboring atoms. The parameters of the model are found from the requirement that self-consistent moments on atoms and density of states found from ab initio and model calculations within the Hartree-Fock approximation are close to each other as much as possible. Contrary to the commonly accepted statement that in the ordered Fe3Si and FexSi1−x alloys an increase of the Si concentration within nearest environment of Fe atoms results in a decrease of Fe magnetic moment we find that a crucial role in the formation of magnetic moments is played by the second coordination sphere of Fe atoms. Particularly, the Fe atoms have higher magnetic moments in amorphous films compared to the epitaxial ones due to decreasing the number of iron-atoms in the next nearest environment. Both our model and ab initio calculations confirm existence of known spin crossover with pressure and predict second crossover at higher pressure.
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