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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Aplesnin S. S.
Заглавие : Static and dynamic magnetic properties of coupled spin-1/2 antiferromagnetic chains
Место публикации : J. Phys.: Condens. Matter: IOP PUBLISHING LTD, 2000. - Vol. 12, Is. 37. - P.8191-8207. - ISSN 0953-8984, DOI 10.1088/0953-8984/12/37/316
Примечания : Cited References: 21
Предметные рубрики: ONE-DIMENSIONAL ANTIFERROMAGNETS
SYSTEMS
SUSCEPTIBILITY
EXCITATIONS
SR2CUO3
CA2CUO3
KCUF3
Ключевые слова (''Своб.индексиров.''): computational methods--copper compounds--correlation methods--functions--magnetic field effects--magnetic properties--magnetization--monte carlo methods--quantum theory--specific heat--thermal effects--excitation spectroscopy--interchain coupling--intrachain couplings--mean-field approximation--spin-spin correlation function--spinons--antiferromagnetic materials
Аннотация: Calculations of the thermodynamic quantities, and the spectra of spinons, triplet excitations, and two-particle spin-singlet (Delta S-z = 0, +/- 1) excitations for a weakly coupled antiferromagnetic S = 1/2 spin chain are made using a mean-field approximation for the interchain couplings (J(2)) by the quantum Monte Carlo method. The mass gaps in these excitation spectra are estimated as functions of the interchain coupling. The critical held H-c, and the temperatures at which the spinon and singlet gaps close (T-1 and T-2, respectively) are obtained. Some peculiarities of the staggered magnetization, the specific heat, and the spin-spin correlation function are found at T-1 = 0.9J(2), T-2 = 1.5J(2), H-c = 3.8J(2), as determined by linear function fitting for J(2)/J(1) 0.15 The intrachain and interchain couplings, and the staggered magnetization for KCuF3, Sr2CuO3, and Ca2CuO3 are estimated, and mass gaps are predicted to exist in the spectra of the spinons and the singlet two-particle excitations.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Berman G. P., Kolovskii A. R.
Заглавие : Quantum chaos in interactions of multilevel quantum-systems with a coherent radiation-field
Место публикации : Uspekhi Fiz. Nauk. - 1992. - Vol. 162, Is. 4. - P.95-141. - ISSN 0042-1294
Примечания : Cited References: 36
Предметные рубрики: QUASIENERGY FUNCTIONS
RESONANCES
BEHAVIOR
OVERLAP
Аннотация: The paper is short review of the papers devoted to the dynamics of the multilevel quantum systems affected by the external periodic field. The main attention is paid to the phenomenon of the quantum nonlinear resonance and the interaction of the two quantum nonlinear resonances, when the dynamics of the system is chaotic in the classical limit. The paper also contains the analysis of some physical systems where these phenomena take place. 30 figs. 37 refs.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Bulgakov E. N., Maksimov D. N., Sadreev A. F.
Заглавие : Electric circuit networks equivalent to chaotic quantum billiards
Место публикации : Phys. Rev. E: AMERICAN PHYSICAL SOC, 2005. - Vol. 71, Is. 4. - Ст.46205. - ISSN 1063-651X, DOI 10.1103/PhysRevE.71.046205
Примечания : Cited References: 31
Предметные рубрики: TIME-REVERSAL SYMMETRY
CONDUCTANCE FLUCTUATIONS
STATISTICS
SYSTEMS
EIGENFUNCTIONS
DOTS
Ключевые слова (''Своб.индексиров.''): chaotic quantum billiards--electric resonance circuits (erc)--resonance networks--wave functions--boundary conditions--capacitors--chaos theory--eigenvalues and eigenfunctions--electric inductors--natural frequencies--quantum theory--resonance--statistical mechanics--networks (circuits)
Аннотация: We consider two electric RLC resonance networks that are equivalent to quantum billiards. In a network of inductors grounded by capacitors, the eigenvalues of the quantum billiard correspond to the squared resonant frequencies. In a network of capacitors grounded by inductors, the eigenvalues of the billiard are given by the inverse of the squared resonant frequencies. In both cases, the local voltages play the role of the wave function of the quantum billiard. However, unlike for quantum billiards, there is a heat power because of the resistance of the inductors. In the equivalent chaotic billiards, we derive a distribution of the heat power which describes well the numerical statistics.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Bulgakov E. N., Pichugin K. N., Sadreev A. F.
Заглавие : Giant resonant enhancement of optical binding of dielectric disks
Место публикации : J. Opt. Soc. Am. B. - 2020. - Vol. 37, Is. 11. - P.3335-3340. - ISSN 07403224 (ISSN), DOI 10.1364/JOSAB.402659
Примечания : Cited References: 30. - Russian Science Support Foundation (19-02-00055)
Аннотация: Two-fold variation over the aspect ratio of each disk and distance between disks gives rise to numerous events of avoided crossing of resonances of individual disks. For these events, the hybridized anti-bonding resonant modes can acquire a morphology close to the Mie resonant mode with the high orbital momentum of an equivalent sphere. The �� factor of such resonance can exceed the �� factor of an isolated disk by two orders of magnitude. We show that dual incoherent counterpropagating coaxial Bessel beams with power 1mW/µm2 with frequency resonant to such anti-bonding Mie-like modes result in unprecedented optical binding forces up to tens of nano-Newtons for silicon micrometer-sized disks. We show also that the magnitude and sign of optical forces depend strongly on the longitudinal wave vector of the Bessel beams.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Bulgakov E. N., Sadreev A. F.
Заглавие : Statistics of wave functions and currents induced by spin-orbit interaction in chaotic billiards
Место публикации : Phys. Rev. E: AMER PHYSICAL SOC, 2004. - Vol. 70, Is. 5. - Ст.56211. - ISSN 1539-3755, DOI 10.1103/PhysRevE.70.056211
Примечания : Cited References: 33
Предметные рубрики: HELMHOLTZ-EQUATION
PERSISTENT CURRENTS
ELECTRON-GAS
RINGS
EIGENFUNCTIONS
SYSTEMS
PHASE
Ключевые слова (''Своб.индексиров.''): approximation theory--chaos theory--degrees of freedom (mechanics)--eigenvalues and eigenfunctions--electric field effects--electric potential--electron gas--hamiltonians--heterojunctions--microwaves--statistical methods--chaotic robnik billiards--current distributions--spin-orbit interaction (soi)--wave functions--quantum theory
Аннотация: We show that the wave function and current statistics in chaotic Robnik billiards crucially depend on the constant of the spin-orbit interaction (SOI). For small constant the current statistics is described by universal current distributions derived for slightly opened chaotic billiards [Saichev et al. J. Phys. A. 35, L87 (2002)] although one of the components of the spinor eigenfunctions is not universal. For strong SOI both components of the spinor eigenstate are complex random Gaussian fields. This observation allows us to derive the distributions of spin-orbit persistent cut-rents which well describe numerical statistics. For intermediate values of the statistics of the eigenstates and currents, both are deeply nonuniversal.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Denisova L. T., Molokeev M. S., Ryabov V. V., Kargin Y. F., Chumilina L. G., Denisov V. M.
Заглавие : Crystal structure and thermodynamic properties of titanate ErGaTi2O7
Место публикации : Russ. J. Inorg. Chem. - 2021. - Vol. 66, Is. 4. - P.532-537. - ISSN 00360236 (ISSN), DOI 10.1134/S0036023621040082
Примечания : Cited References: 29
Аннотация: Erbium gallium titanate was prepared by solid-phase synthesis via the sequential calcination of precursor oxides in an air atmosphere at 1273 and 1573 K. The crystal structure of ErGaTi2O7 was characterized by full-profile analysis for the X-ray diffraction pattern of the synthesized powder sample as follows: space group Pcnb, a = 9.77326(15) Å, b = 13.5170(2) Å, c = 7.33189(11) Å, V = 918.58(3) Å3, ρ = 6.10 g/cm3. The high-temperature heat capacity of erbium gallium titanate was measured by differential scanning calorimetry within a temperature range of 320–1000 K. Based on these data, the basic thermodynamic functions of ErGaTi2O7 were calculated.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Slobodchikov, Anatoly A., Nekrasov, Igor A., Begunovich L. V., Makarov I. A., Korshunov M. M., Ovchinnikov S. G.
Заглавие : Electronic structure and minimal models for flat and corrugated CuO monolayers: An ab initio study
Место публикации : Materials. - 2023. - Vol. 16, Is. 2. - Ст.658. - ISSN 1996-1944 (ISSN), DOI 10.3390/ma16020658
Примечания : Cited References: 24. - This research was in part funded by the Russian Science Foundation grant number 23-22-00372
Аннотация: CuO atomic thin monolayer (mlCuO) was synthesized recently. Interest in the mlCuO is based on its close relation to CuO2 layers in typical high temperature cuprate superconductors. Here, we present the calculation of the band structure, the density of states and the Fermi surface of the flat mlCuO as well as the corrugated mlCuO within the density functional theory (DFT) in the generalized gradient approximation (GGA). In the flat mlCuO, the Cu-3dx2−y2 band crosses the Fermi level, while the Cu-3dxz,yz hybridized band is located just below it. The corrugation leads to a significant shift of the Cu-3dxz,yz hybridized band down in energy and a degeneracy lifting for the Cu-3dx2−y2 bands. Corrugated mlCuO is more energetically favorable than the flat one. In addition, we compared the electronic structure of the considered CuO monolayers with bulk CuO systems. We also investigated the influence of a crystal lattice strain (which might occur on some interfaces) on the electronic structure of both mlCuO and determined the critical strains of topological Lifshitz transitions. Finally, we proposed a number of different minimal models for the flat and the corrugated mlCuO using projections onto different Wannier functions basis sets and obtained the corresponding Hamiltonian matrix elements in a real space.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gorban A., Popova T., Zinovyev A.
Заглавие : Codon usage trajectories and 7-cluster structure of 143 complete bacterial genornic sequences
Разночтения заглавия :авие SCOPUS: Codon usage trajectories and 7-cluster structure of 143 complete bacterial genomic sequences
Место публикации : Physica A: ELSEVIER SCIENCE BV, 2005. - Vol. 353. - P365-387. - ISSN 0378-4371, DOI 10.1016/j.physa.2005.01.043
Примечания : Cited References: 46
Предметные рубрики: DNA-BASE COMPOSITION
ASYMMETRIC SUBSTITUTION PATTERNS
PROTEIN-CODING REGIONS
MICROBIAL GENOMES
GENE IDENTIFICATION
MARKOV-MODELS
G+C CONTENT
BIAS
PREDICTION
SELECTION
Ключевые слова (''Своб.индексиров.''): genome--cluster--codon usage--correlations--entropy--mean field--cluster--codon usage--correlations--entropy--genome--mean field--approximation theory--correlation methods--database systems--entropy--functions--genes--mathematical models--clusters--codon usage--genomes--mean field--bacteria
Аннотация: Three results are presented. First, we prove the existence of a universal 7-cluster structure in all 143 completely sequenced bacterial genomes available in Genbank in August 2004, and explained its properties. The 7-cluster structure is responsible for the main part of sequence heterogeneity in bacterial genomes. In this sense, our 7 clusters is the basic model of bacterial genome sequence. We demonstrated that there are four basic "pure" types of this model, observed in nature: "parallel triangles", "perpendicular triangles", degenerated case and the flower-like type. Second, we answered the question: how big are the position-specific information and the contribution connected with correlations between nucleotide. The accuracy of the mean-field (context-free) approximation is estimated for bacterial genomes. We show that codon us-age of bacterial genomes is a multi-linear function of their genomic G+C-content with high accuracy (more precisely, by two similar functions, one for eubacterial genomes and the other one for archaea). Description of these two codon-usage trajectories is the third result. All 143 cluster animated 3D-scatters are collected in a database and is made available on our web-site: http://www.ihes.fr/similar to zinovyev/7clusters. (c) 2005 Elsevier B.V. All rights reserved.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Goryachev E. G., Kuzmin E. V., Ovchinnikov S. G.
Заглавие : Metal-insulator-transition in the hubbard-model by the irreducible green-functions method
Разночтения заглавия :авие SCOPUS: Metal-insulator transition in the Hubbard model by the irreducible Green functions method
Место публикации : Journal of Physics C - Solid State Physics. - 1982. - Vol. 15, Is. 7. - P1481-1493. - ISSN 0022-3719, DOI 10.1088/0022-3719/15/7/015
Примечания : Cited References: 18
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Denisova L. T., Molokeev M. S., Chumilina L. G., Ryabov V. V., Denisov V. M.
Заглавие : Heat capacity and thermodynamic functions of GdGaTi2O7 in the temperature range of 320-1000 K
Место публикации : Phys. Solid State. - 2021. - Vol. 63, Is. 4. - P.534-537. - ISSN 1063-7834, DOI 10.1134/S1063783421040065. - ISSN 1090-6460(eISSN)
Примечания : Cited References: 17
Аннотация: Titanate GdGaTi2O7 has been obtained from the initial oxides Gd2O3, Ga2O3, and TiO2 by the solid-state synthesis via annealing in air at temperatures of 1273 and 1573 K. The crystal structure of the titanate has been refined by X-ray diffraction. The high-temperature (320–1000 K) heat capacity of the compound has been measured by differential scanning calorimetry. Based on the experimental dependence Cp = f(T), the main thermodynamic functions of the titanate have been calculated.
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : IGNATCHENKO V. A., ISKHAKOV R. S.
Заглавие : CORRELATION-FUNCTIONS OF RANDOM ANISOTROPY AND THE PROBLEM OF FERROMAGNET STATE STABILITY
Место публикации : Journal de Physique. - 1988. - Vol. 49, Is. C-8. - P.1245-1246. - ISSN 0302-0738, DOI 10.1051/jphyscol:19888565
Примечания : Cited References: 8
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ignatchenko V. A., Polukhin D. S.
Заглавие : Development of a self-consistent approximation
Место публикации : J. Phys. A: IOP Publishing, 2016. - Vol. 49, Is. 9. - Ст.095004. - ISSN 17518113 (ISSN), DOI 10.1088/1751-8113/49/9/095004
Примечания : Cited References: 43
Предметные рубрики: SUPERCONDUCTING CRITICAL-TEMPERATURE
LATTICE-VIBRATIONS
VERTEX FUNCTION
ELECTRON
Ключевые слова (''Своб.индексиров.''): self-consistent approximation--green's functions--vertex corrections--inhomogeneities--correlations--dynamic susceptibility
Аннотация: A self-consistent approximation of a higher level than the standard self-consistent approximation, known in various fields of physics as the Migdal, Kraichnan or Born self-consistent approximation, is derived taking into account both the first and second terms of the series for the vertex function. In contrast to the standard approximation, the new self-consistent approximation is described by a system of two coupled nonlinear integral equations for the self-energy and the vertex function. In addition to all the diagrams with non-intersecting lines of correlation/interaction taken into account by the standard self-consistent approximation, the new approach takes into account in each term of the Green's function expansion a significant number of diagrams with intersections of these lines. Because of this, the shape, linewidth, and amplitude of the resonance peaks of the dynamic susceptibility calculated in this approximation are much closer to the exact values of these characteristics. The advantage of the new self-consistent approach is demonstrated by the example of calculation of the dynamic susceptibility of waves in an inhomogeneous medium. © 2016 IOP Publishing Ltd.
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13.

Вид документа : Статья из сборника (выпуск продолж. издания)
Шифр издания :
Автор(ы) : Ignatchenko V. A., Polukhin D. S.
Заглавие : Green's functions of polaritons in a medium with zero-mean inhomogeneous coupling parameter
Коллективы : International Conference on Photonics of Nano- and Bio-Structures, International Conference on Photonics of Nano- and Bio-Structures
Место публикации : Physics Procedia: Elsevier, 2017. - Vol. 86. - P.117-121. - , DOI 10.1016/j.phpro.2017.01.031
Примечания : Cited References: 10
Ключевые слова (''Своб.индексиров.''): electromagnetic waves--optical phonons--crossing resonance--polaritons--green's functions--self-consistent approximation
Аннотация: Dynamic susceptibilities (Green's functions) of the interacting electromagnetic waves G”e(ω) and optical phonons G”u(ω) in a medium with zero-mean inhomogeneous coupling parameter have been considered. The calculation was performed using a self-consistent approximation for the two stochastically interacting wave fields. It is shown that on the tops of the resonance maxima of the imaginary parts of the Green functions the fine structure is formed: a minimum (dip) on the top of G”e(ω) and narrow maximum (peak) on the top of G”u(ω). With increasing the correlation wavenumber of inhomogeneities kc (i.e., with decreasing the size of inhomogeneities), the width of the peak on G”u(ω) decreases, and two resonance maxima in the function G”e(ω) are formed. Because of the large difference in the speeds of light and optical phonons, the fine structure of the polaritons is manifested itself more clearly and saved to a much larger values of kc, than for the studied earlier crossing resonance of spin and elastic waves.
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ignatchenko V. A., Tsikalov D. S.
Заглавие : Green's functions of the scalar model of electromagnetic fields in sinusoidal superlattices
Место публикации : Physica B: Elsevier, 2016. - Vol. 485. - P.94-102. - ISSN 09214526 (ISSN), DOI 10.1016/j.physb.2016.01.006
Примечания : Cited References: 30
Предметные рубрики: SCATTERING
MEDIA
PROPAGATION
GRATINGS
DENSITY
LIGHT
Ключевые слова (''Своб.индексиров.''): green's functions--electromagnetic waves--scalar model--sinusoidal superlattices--photonic crystals--ldos
Аннотация: Problems of obtaining Green's function and using it for studying the structure of scalar electromagnetic fields in a sinusoidal superlattice are considered. An analytical solution of equation in the k-space for Green's function is found. Green's function in the r-space is obtained by both the numerical and the approximate analytical Fourier transformation of that solution. It is shown, that from the experimental study of Green's function in the k-space the position of the plane radiation source relative to the extremes of the dielectric permittivity ?(z) can be determined. The relief map of Green's function in the r-space shows that the structure of the field takes the form of chains of islets in the plane ?z, the number of which increases with increasing the distance from a radiation source. This effect leads to different frequency dependences of Green's function at different distances from the radiation source and can be used to measure the distance to the internal source. The real component of Green's function and its spatial decay in the forbidden zones in the near field is investigated. The local density of states, depending on the position of the source in the superlattice, is calculated.
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ignatchenko V. A., Polukhin D. S.
Заглавие : Green’s function of magnetoelastic waves
Коллективы : Moscow International Symposium on Magnetism
Место публикации : Solid State Phenom.: Selected, peer reviewed papers/ ed.: N. Perov, A. Semisalova: Trans Tech Publications Ltd, 2015. - Vol. 233-234: Achievements in Magnetism. - P.12-15. - ISSN 1662-9779, DOI 10.4028/www.scientific.net/SSP.233-234.12. - ISSN 978-3-03835-482-6
Ключевые слова (''Своб.индексиров.''): dispersion relations--elastic waves--green’s functions--magnetoelastic coupling--resonances--spin waves--green's function--resonance--spin waves--wave propagation--approximate expressions--dipole dipole interactions--dispersion relations--elastic oscillations--longitudinal elastic wave--magnetoelastic couplings--off-diagonal elements--s function--elastic waves
Аннотация: The matrix (5x5) Green's function of magnetoelastic waves in an isotropic magnetoelastic medium taking into account the dipole-dipole interaction has been derived. The imaginary parts of diagonal and off-diagonal elements of the Green's function in the crossing resonance of spin and longitudinal elastic waves has been investigated. It is shown that under changing the angle of wave propagation θ the amplitudes of Green functions change drastically due redistribution of energy between the magnetic and elastic oscillation. Approximate expressions for the dependence of the widths of the gaps in the spectrum on the angle θ have been also derived. © (2015) Trans Tech Publications, Switzerland.
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ignatchenko V. A., Tsikalov D. S.
Заглавие : Green’s functions of spin and electromagnetic waves in the sinusoidal superlattice
Коллективы : Moscow International Symposium on Magnetism
Место публикации : Solid State Phenom.: Selected, peer reviewed papers/ ed.: N. Perov, A. Semisalova: Trans Tech Publications Ltd, 2015. - Vol. 233-234: Achievements in Magnetism. - P.47-50. - ISSN 1662-9779, DOI 10.4028/www.scientific.net/SSP.233-234.47. - ISSN 978-3-03835-482-6
Ключевые слова (''Своб.индексиров.''): continued fractions--electromagnetic waves--green’s functions--magnonic crystals--photonic crystals--sinusoidal modulation--spin waves--superlattices--circular waveguides--fourier transforms--green's function--photonic crystals--spin waves--superlattices--analytical expressions--continued fraction--fourier transformations--magnonic crystals--s function--sinusoidal modulation--spectral representations--electromagnetic waves
Аннотация: The problem of finding the Green's function of spin and electromagnetic waves in the sinusoidal superlattice is considered. An analytical expression for the spectral representation of the Green's function has been found in the form of ascending continued fractions, the particular denominators of which are ordinary continued fractions. The Green’s function in the r -space has been found by the numerical Fourier transformation of the Greens’s function found in the spectral representation. © (2015) Trans Tech Publications, Switzerland.
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ignatchenko V. A., Mankov Y. I., Tsikalov D. S.
Заглавие : High-Frequency Susceptibility of a Superlattice with 2D Inhomogeneities
Коллективы :
Разночтения заглавия :авие SCOPUS: High-frequency susceptibility of a superlattice with 2D inhomogeneities
Место публикации : J. Exp. Theor. Phys.: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2008. - Vol. 107, Is. 4. - P603-611. - ISSN 1063-7761, DOI 10.1134/S1063776108100075
Примечания : Cited References: 26. - This work was supported in part by grant no. 3818.2008.3 from the President of Russia in accordance with the program supporting leading scientific schools.
Предметные рубрики: SPIN-WAVE SUSCEPTIBILITY
PERIODIC MULTILAYERS
LOCALIZATION
SYSTEMS
SPECTRUM
DISORDER
MEDIA
Ключевые слова (''Своб.индексиров.''): energy conservation--energy gap--energy management--frequency bands--gallium alloys--green's function--probability density function--three dimensional--band gaps--energy conservation laws--green functions--high frequencies--imaginary parts--magnon crystals--scattered waves--superlattice layers--wave spectrums--phase interfaces
Аннотация: We investigate the high-frequency susceptibility (Green function) of an initially sinusoidal 1D superlattice with 2D phase inhomogeneities that model the deformations of the interfaces between the superlattice layers. For waves propagating along the superlattice axis ( the geometry of a photon or magnon crystal), we have found a peculiar behavior of the imaginary part of the Green function that consists in a significant difference between the peaks corresponding to the edges of the band gap in the wave spectrum. The peak corresponding to the lower-frequency band edge remains essentially unchanged as the root-mean-square fluctuation of the 2D inhomogeneities. 2 increases, while the peak corresponding to the higher-frequency band edge broaden and decreases sharply in height until its complete disappearance with increasing gamma(2). This behavior of the peaks corresponds to a band gap closure mechanism that differs from the traditional one characteristic of 1D and 3D inhomogeneities. These effects can be explained by a peculiarity of the energy conservation laws for the incident and scattered waves for 2D inhomogeneities in a 1D superlattice.
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ignatchenko V. A., Polukhin D. S.
Заглавие : Magnetoelastic resonance in media with the inhomogeneous coupling parameter
Коллективы : Euro-Asian Symposium "Trends in MAGnetism": Nanomagnetism
Место публикации : Solid State Phenom.: Selected, peer reviewed papers/ ed.: S. G. Ovchinnikov, A. Samardak: Trans Tech Publications, 2014. - Vol. 215: Trends in Magnetism: Nanomagnetism (EASTMAG-2013). - P.105-108. - DOI 10.4028/www.scientific.net/SSP.215.105. - ISSN 1662-9779
Примечания : Cited References: 8
Ключевые слова (''Своб.индексиров.''): elastic waves--green's functions--inhomogeneities--magnetoelastic coupling--self-consistent approximation--spin waves
Аннотация: The matrix Green's function of coupled spin and elastic waves for media with the 3D inhomogeneities of the coupling parameter is studied. It has been shown that the difference in shapes of the Green's functions for the cases of 1D and 3D inhomogeneities appears only for the sufficiently large correlation wave number of the inhomogeneities. © (2014) Trans Tech Publications, Switzerland.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ignatchenko V. A., Polukhin D. S., Tsikalov D. S.
Заглавие : Self-consistent approximation: Development and application to the problem of waves in inhomogeneous media
Коллективы : Euro-Asian Symposium "Trends in MAGnetism", "Trends in MAGnetism", Euro-Asian Symposium, Институт физики им. Л.В. Киренского Сибирского отделения РАН , SB of the Russian Academy of Sciences [II.2P (0356-2015-0410)]
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.83-86. - ISSN 0304-8853, DOI 10.1016/j.jmmm.2016.12.058. - ISSN 1873-4766(eISSN)
Примечания : Cited References:20. - This work was supported in part by the Complex Program No II.2P (0356-2015-0410) of the SB of the Russian Academy of Sciences.
Предметные рубрики: SUPERCONDUCTING CRITICAL-TEMPERATURE
MIGDALS THEOREM
VERTEX FUNCTION
Ключевые слова (''Своб.индексиров.''): self-consistent approximation--greens functions--vertex corrections--inhomogeneities--correlations--dynamic susceptibility
Аннотация: A new self-consistent approximation proposed earlier, is compared with various existing approximations, as well as with a numerical simulation of solutions of the wave equation for a medium with one-dimensional inhomogeneities. The Green's function, found using the new approach, is the closest to the result obtained by the numerical simulation. The results of the work show that the new approach has undoubted advantages in the study of stochastic problems in media with longwave inhomogeneities. The new self-consistent approximation in some cases has advantages over a numerical method: a more rapid process of calculation and the possibility of consideration of three-dimensional problems.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Korshunov M. M., Eremin I., Shorikov A., Anisimov V. I., Renner M., Brenig W.
Заглавие : Itinerant in-plane magnetic fluctuations and many-body correlations in NaxCoO2
Разночтения заглавия :авие SCOPUS: Itinerant in-plane magnetic fluctuations and many-body correlations in Nax Co O2
Место публикации : Phys. Rev. B: AMERICAN PHYSICAL SOC, 2007. - Vol. 75, Is. 9. - Ст.94511. - ISSN 1098-0121, DOI 10.1103/PhysRevB.75.094511
Примечания : Cited References: 47
Предметные рубрики: TRANSITION-METALS
WAVE-FUNCTIONS
HUBBARD-MODEL
FERMI-SURFACE
ENERGY-BANDS
FERROMAGNETISM
APPROXIMATION
DIMENSIONS
SYSTEMS
FIELD
Аннотация: Based on the ab initio band structure for NaxCoO2, we derive the single-electron energies and the effective tight-binding description for the t(2g) bands using projection procedure. Due to the presence of the next-nearest-neighbor hoppings, a local minimum in the electronic dispersion close to the Gamma point of the first Brillouin zone forms. Correspondingly, in addition to a large Fermi surface, an electron pocket close to the Gamma point emerges at high doping concentrations. The latter yields a scattering channel, resulting in a peak structure of the itinerant magnetic susceptibility at small momenta. This indicates dominant itinerant in-plane ferromagnetic fluctuations above a certain critical concentration x(m), in agreement with neutron scattering data. Below x(m), the magnetic susceptibility shows a tendency toward the antiferromagnetic fluctuations. We further analyze the many-body effects on the electronic and magnetic excitations using various approximations applicable for different U/t ratios.
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