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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Petrov M. I., Balaev D. A., Gokhfel'd D. M., Shaikhutdinov K. A.
Заглавие : Andreev reflection in natural grain boundaries of polycrystalline high-T-c superconductor La1.85Sr0.15CuO4
Разночтения заглавия :авие SCOPUS: Andreev reflection in natural grain boundaries of polycrystalline high-Tc superconductor La1.85Sr0.15CuO 4
Место публикации : Phys. Solid State: AMER INST PHYSICS, 2003. - Vol. 45, Is. 7. - P1219-1222. - ISSN 1063-7834, DOI 10.1134/1.1594233
Примечания : Cited References: 30
Предметные рубрики: CURRENT-VOLTAGE CHARACTERISTICS
WEAK LINKS
CHARGE-TRANSPORT
JUNCTIONS
CONDUCTIVITY
HYSTERESIS
COMPOSITES
SCATTERING
Аннотация: The temperature evolution of the current-voltage characteristic (CVC) of a "break junction" with metal-type conductivity on the polycrystalline La1.85Sr0.15CuO4 high-temperature superconductor is investigated. The CVC exhibits gap peculiarities and hysteresis, which is observed in the region of negative differential resistance. The experimental results are described well in terms of the Kummel-Gunsenheimer-Nicolsky theory for an S-N-S junction (S is a superconductor, N is a normal metal) this theory takes into account multiple Andreev reflection of quasiparticles. It is shown that the shape of the CVC and the existence and the shape of hysteresis are determined by the ratio of "long" and "short" grain boundaries in the polycrystal under investigation. (C) 2003 MAIK "Nauka / Interperiodica".
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Aplesnin S. S.
Заглавие : Quantum Monte Carlo investigation of the magnetic properties of weakly interacting antiferromagnetic chains with an alternating exchange interaction with spin S=1/2
Место публикации : J. Exp. Theor. Phys.: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2000. - Vol. 90, Is. 1. - P194-201. - ISSN 1063-7761, DOI 10.1134/1.559075
Примечания : Cited References: 35
Предметные рубрики: PEIERLS COMPOUND CUGEO3
MAGNON DISPERSION
BI2CUO4
EXCITATIONS
RESONANCE
SYSTEMS
SCATTERING
DYNAMICS
NEUTRON
PHASE
Аннотация: An approximation dependence of the spontaneous magnetic moment at a site, sigma/sigma(0) - 1 = 0.71(6)delta(2.5(2)), and the antiferromagnet-singlet state phase boundary, J(2)/J(1) = 0.52(3)delta, are determined by the quantum Monte Carlo method in the self-consistent sublattice molecular field approximation for weakly interacting (J(2)) antiferromagnetic chains with spin S = 1/2 and alternating exchange interaction (J(1) +/- delta). The Neel temperature and a number of critical temperatures which could be related with the filling energy of two singlets (Delta S-z = 0) and one triplet (Delta S-z= 1) spin bands, each of which is split by the sublattice field (h(x,y)not equal h(z)) into two subbands, are determined on the basis of the computed correlation radii of the two- and four-spin correlation function, the squared total spin (S-z)(2) with respect to the longitudinal components, the dimerization parameter, and the correlation functions between the nearest neighbors with respect to longitudinal and transverse spin components. On the basis of the Monte Carlo calculations, the critical temperatures and possible energy gaps at the band center are determined for the antiferromagnets CuWO4 and Bi2CuO4 and for the singlet compounds (VO)(2)P2O7 and CuGeO3 , agreeing satisfactorily with existing results, and new effects are also predicted. (C) 2000 MAIK "Nauka / Interperiodica".
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Aver'yanov E. M., Rumyantsev V. G.
Заглавие : Manifestations of the higher moments of the orientation distribution function of molecules in the spectral properties of an impurity nematic
Место публикации : J. Exp. Theor. Phys.: AMER INST PHYSICS, 2004. - Vol. 98, Is. 6. - P1146-1151. - ISSN 1063-7761, DOI 10.1134/1.1777627
Примечания : Cited References: 15
Предметные рубрики: LIQUID-CRYSTAL
SCATTERING
PHASES
MATRIX
ORDER
DYES
Ключевые слова (''Своб.индексиров.''): absorption--band structure--impurities--molecular dynamics--polarization--spectrum analysis--distribution function--local field parameters--splitting--temperature dependence--nematic liquid crystals
Аннотация: The polarized electronic absorption spectra, orientation ordering, and the special local field features were studied for push-pull linear dye molecules with strong donor-acceptor electronic conjugation of terminal fragments in the matrix of a nematic liquid crystal. The temperature-induced inversion of the sign of the splitting of polarized impurity absorption bands was observed. This effect was shown to be caused by the statistical character of orientation ordering of impurity molecules and manifestation of the higher moments of the orientation distribution function. The dependence of local field parameters (Lorentz tensor components) of impurity molecules on their orientation ordering was established. This dependence was used to reproduce the temperature dependence of the orientation order parameter of the matrix. (C) 2004 MAIK "Nauka / Interperiodica".
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Bulgakov E. N., Pichugin K. N., Sadreev A. F., Rotter I.
Заглавие : Bound states in the continuum in open Aharonov-Bohm rings
Место публикации : JETP Letters. - 2006. - Vol. 84, Is. 8. - P.430-435. - ISSN 0021-3640, DOI 10.1134/S0021364006200057
Примечания : Cited References: 33
Предметные рубрики: WAVE-GUIDE
QUANTUM
TRANSMISSION
SCATTERING
BILLIARDS
ELECTRON
Аннотация: Using the formalism of the effective Hamiltonian, we consider bound states in a continuum (BIC). They are nonhermitian effective Hamiltonian eigenstates that have real eigenvalues. It is shown that BICs are orthogonal to open channels of the leads, i.e., disconnected from the continuum. As a result, BICs can be superposed to a transport solution with an arbitrary coefficient and exist in a propagation band. The one-dimensional Aharonov-Bohm rings that are opened by attaching single-channel leads to them allow exact consideration of BICs. BICs occur at discrete values of the energy and magnetic flux; however, it's realization strongly depends on the way to the BIC point.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Bulgakov E. N., Sadreev E. N.
Заглавие : Bloch bound states in the radiation continuum in a periodic array of dielectric rods
Коллективы : Russian Science Foundation [14-12-00266]
Место публикации : Phys. Rev. A: American Physical Society, 2014. - Vol. 90, Is. 5. - Ст.53801. - ISSN 1050-2947, DOI 10.1103/PhysRevA.90.053801. - ISSN 1094-1622
Примечания : Cited References: 35. - The work was supported by the Russian Science Foundation through Grant No. 14-12-00266. We acknowledge discussions with D. N. Maksimov.
Предметные рубрики: WAVE-GUIDE
SCATTERING
CYLINDERS
CHANNEL
Аннотация: We consider an infinite periodic array of dielectric rods in vacuum with the aim to demonstrate three types of Bloch bound states in the continuum (BSCs): symmetry protected with a zero Bloch vector, embedded in one diffraction channel with nonzero Bloch vector, and embedded in two and three diffraction channels. The first and second types of the BSC exist for a wide range of material parameters of the rods, while the third occurs only at a specific value of the radius of the rods. We show that the second type supports the power flux along the array. In order to find BSCs we put forward an approach based on the expansion over the Hankel functions. We show how the BSC reveals itself in the scattering function when the singular BSC point is approached along a specific path in the parametric space.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Bulgakov E. N., Sadreev A. F.
Заглавие : Formation of bound states in the continuum for a quantum dot with variable width
Место публикации : Phys. Rev. B: AMER PHYSICAL SOC, 2011. - Vol. 83, Is. 23. - Ст.235321. - ISSN 1098-0121, DOI 10.1103/PhysRevB.83.235321
Примечания : Cited References: 61
Предметные рубрики: NUCLEAR REACTIONS
RADIATION-FIELD
UNIFIED THEORY
WAVE-GUIDE
TRANSMISSION
SCATTERING
BILLIARDS
ELECTRON
Аннотация: We consider mechanisms of formation of the bound states in the continuum in open rectangular quantum dots with variable width. Because of symmetry there might be bound states in the continuum (BSCs) embedded into one, two, and three continua because of the symmetry of system. These BSCs arise for selected values of the width. We show numerically that the BSCs can be excited for transmission of wave packets if the quantum dot width is varied in time and reaches these selected values of dot width. Moreover, we consider numerically a decay process of different eigenstates in the closed quantum dot to show that some of them trap in the BSC after the quantum dot is opened.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Chubukov A. V., Eremin I., Korshunov M. M.
Заглавие : Theory of Raman response of a superconductor with extended s-wave symmetry: Application to the iron pnictides
Коллективы : NSF [DMR 0604406]; Asian-Pacific Center for Theoretical Physics; Volkswagen Foundation [I/82203]; RMHE Program "Development of scientific potential" [N1 2.1.1/298.5]; RFBR [09-02-00127]
Разночтения заглавия :авие SCOPUS: Theory of Raman response of a superconductor with extended s -wave symmetry: Application to the iron pnictides
Место публикации : Phys. Rev. B: AMER PHYSICAL SOC, 2009. - Vol. 79, Is. 22. - Ст.220501. - ISSN 1098-0121, DOI 10.1103/PhysRevB.79.220501
Примечания : Cited References: 48. - We acknowledge useful conversations with G. Blumberg, W. Brenig, H.-Y. Choi, D. V. Efremov, A. Sacuto, M. Vavilov, and A. Vorontsov. A. V. C. acknowledges support from NSF (Contract No. NSF-DMR 0604406). I. E. acknowledges partial support from the Asian-Pacific Center for Theoretical Physics, the Volkswagen Foundation (Contract No. I/82203), and the RMHE Program "Development of scientific potential" (Contract No. N1 2.1.1/298.5). M. M. K. acknowledges support from RFBR (Grant No. 09-02-00127) and RAS program on "Low temperature quantum phenomena."
Предметные рубрики: LAYERED SUPERCONDUCTOR
SCATTERING
BA0.6K0.4FE2AS2
Аннотация: We argue that Raman study of Fe-pnictides is a way to unambiguously distinguish between various superconducting gaps proposed for these materials. We show that A(1g) Raman intensity develops a true resonance peak below 2 Delta if the pairing gap has A(1g) symmetry in the folded Brillouin zone (Delta(k=0)=Delta, Delta(pi, pi)=-Delta). No such peak develops for a pure s-wave gap, a d-wave gap, and an extended s-wave gap with Delta(k) =Delta cosk(x)/2cosk(y)/2. We show that the peak remains quite strong for the values of interpocket impurity scattering used to fit NMR data.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Boehm M., Roessli B., Schefer J., Wills A. S., Ouladdiaf B., Lelievre-Berna E., Staub U., Petrakovskii G. A.
Заглавие : Complex magnetic ground state of CuB2O4
Место публикации : Phys. Rev. B: AMER PHYSICAL SOC, 2003. - Vol. 68, Is. 2. - Ст.24405. - ISSN 1098-0121, DOI 10.1103/PhysRevB.68.024405
Примечания : Cited References: 16
Предметные рубрики: COPPER METABORATE
SCATTERING
Аннотация: The magnetic ground-state of copper metaborate CuB2O4 was investigated with unpolarized and polarized neutron scattering. A phase transition was found at T-N = 21 K to a commensurate weakly ferromagnetic state followed by a second transition at T* = 10 K to an incommensurate magnetic structure. Neutron diffraction revealed a continuously changing magnetic propagation vector below T*, and unusually asymmetric magnetic satellite reflections. Additionally, diffuse scattering is observed in the temperature range 1.5 K less than or equal to Tless than or equal to 30 K. The magnetic structure determined in both phases are shown to be consistent with results of symmetry analysis. In particular, we find that only one of the two inequivalent Cu2+ sublattice fully orders down to the lowest temperature. Our results show that the complex magnetic behavior of copper metaborate is a consequence of mutual interaction between the two Cu2+ sublattices with different ordering temperatures.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ershov A. E., Isaev I. L., Semina P. N., Markel V. A., Karpov S. V.
Заглавие : Effects of size polydispersity on the extinction spectra of colloidal nanoparticle aggregates
Место публикации : Phys. Rev. B: American Physical Society, 2012. - Vol. 85, Is. 4. - Ст.045421. - P. - ISSN 1098-0121, DOI 10.1103/PhysRevB.85.045421
Примечания : Cited References: 41. - This work was supported by grants from the following foundations of the Russian Federation: Presidium of RAS, OFN RAS, and SB RAS.
Предметные рубрики: METAL FRACTAL CLUSTERS
OPTICAL-PROPERTIES
ABSORPTION
NONLINEARITIES
COMPOSITES
SCATTERING
PARTICLES
SPHERES
GRAINS
Аннотация: We investigate the effect of particle polydispersity on the optical extinction spectra of colloidal aggregates of spherical metallic (silver) nanoparticles, taking into account the realistic interparticle gaps caused by layers of stabilizing polymer adsorbed on the metal surface (adlayers). The spectra of computer-generated aggregates are computed using two different methods. The coupled-multipole method is used in the quasistatic approximation and the coupled-dipole method beyond the quasistatics. The latter approach is applicable if the interparticle gaps are sufficiently wide relative to the particle radii. Simulations are performed for two different particle size distribution functions (bimodal and Gaussian), varying the number of particles per aggregate, and different distribution functions of the interparticle gap width. The strong influence of the latter factor on the spectra is demonstrated and investigated in detail.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Pisarev R. V., Kalashnikova A. M., Schops O., Bezmaternykh L. N.
Заглавие : Electronic transitions and genuine crystal-field parameters in copper metaborate CuB2O4
Разночтения заглавия :авие SCOPUS: Electronic transitions and genuine crystal-field parameters in copper metaborate CuB 2O 4
Место публикации : Phys. Rev. B: AMER PHYSICAL SOC, 2011. - Vol. 84, Is. 7. - Ст.75160. - ISSN 1098-0121, DOI 10.1103/PhysRevB.84.075160
Примечания : Cited References: 65. - Useful discussions with W. Weber on crystal-field splitting of 3d states in cuprates are appreciated. We thank H.-J. Weber for the help in using Cary 2300 spectrophotometer. This work is supported by the Russian Foundation for Basic Research (project No. 09-02-00070) and Federal Agency for Science and Innovations (Grant No. 02.740.11.0384). A. M. K. acknowledges the financial support from the Committee for Science and Higher Education of the Government of Saint Petersburg.
Предметные рубрики: OPTICAL-ABSORPTION
PHASE-DIAGRAM
CUGEO3
SPECTRUM
SUPERCONDUCTORS
EXCITATIONS
SR2CUO2CL2
SCATTERING
LA2CUO4
CUPRATE
Аннотация: We present and analyze high-resolution alpha-, sigma-, and pi-polarized absorption spectra related to d-d electronic transitions in tetragonal metaborate CuB2O4 where copper Cu2+ ions occupy two crystallographically distinct 4b and 8d positions. The spectra are characterized by exceptionally rich fine structure in the spectral range of 1.4-2.4 eV. Six zero-phonon (ZP) lines originating from the electronic transitions within the Cu2+ ions in both positions are distinguished and identified. Symmetry analysis explains polarization properties of the ZP lines in the 8d positions but only partially explains them in the 4b positions. Reliable assignment of all six ZP lines to specific transitions allowed us to calculate genuine cubic Dq and tetragonal Ds and Dt crystal-field parameters for both positions. We show that the (3r(2) - z(2)) state, the energy of which is the measure of the Jahn-Teller splitting, is the highest 3d state for both types of Cu2+ ion positions. Using the obtained crystal-field parameters as the reference values, we estimated Dq, Ds, and Dt for several other cuprates with different Cu-O bond lengths. In particular, the 3d level splitting in La2CuO4, Nd2CuO4, CuGeO3, Sr2CuO2Cl2, and Cu3B7O13Cl was analyzed. Our estimates suggest that the Jahn-Teller splitting in some of these cuprates is larger than it was assumed previously.
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Parker D., Dolgov O. V., Korshunov M. M., Golubov A. A., Mazin I. I.
Заглавие : Extended s(+/-) scenario for the nuclear spin-lattice relaxation rate in superconducting pnictides
Разночтения заглавия :авие SCOPUS: Extended sВ± scenario for the nuclear spin-lattice relaxation rate in superconducting pnictides
Место публикации : Phys. Rev. B: AMER PHYSICAL SOC, 2008. - Vol. 78, Is. 13. - Ст.134524. - ISSN 1098-0121, DOI 10.1103/PhysRevB.78.134524
Примечания : Cited References: 35
Предметные рубрики: IMPURITIES
SCATTERING
GAPS
Аннотация: Recently, several measurements of the nuclear spin-lattice relaxation rate T(1)(-1) in the superconducting Fe pnictides have been reported. These measurements generally show no coherence peak below T(c) and indicate a low-temperature power-law behavior, the characteristics commonly taken as evidence of unconventional superconductivity with lines of nodes crossing the Fermi surface. In this work we show that (i) the lack of a coherence peak is fully consistent with the previously proposed nodeless extended s(+/-)-wave symmetry of the order parameter (whether in the clean or dirty limit) and (ii) the low-temperature power-law behavior can be also explained in the framework of the same model but requires going beyond the Born limit.
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Jorio A., Currat R., Myles DAA, McIntyre G. J., Aleksandrova I. P., Kiat J. M., Saint-Gregoire P.
Заглавие : Ferroelastic phase transition in Cs3Bi2I9: A neutron diffraction study
Место публикации : Phys. Rev. B: AMERICAN PHYSICAL SOC, 2000. - Vol. 61, Is. 6. - P3857-3862. - ISSN 1098-0121, DOI 10.1103/PhysRevB.61.3857
Примечания : Cited References: 16
Предметные рубрики: CRYSTAL
SCATTERING
CS3SB2I9
Аннотация: Crystalline Cs3Bi2I9, With the P6(3)/mmc symmetry at room temperature was studied by Laue and four-circle neutron diffractometry from room temperature down to 50 K. At T-0 = 220 K the crystal undergoes a second-order proper ferroelastic phase transition to a polydomain structure with a nonprimitive monoclinic C12/m1 space group. Satellites were not found below T-0, indicating that the continuous distribution of sites observed in previous I-127 nuclear quadrupole resonance experiments is due either to an undetected incommensurate phase characterized by a very small displacement amplitude, or due to the fraction of the crystal volume occupied by domain walls. We argue that thick domain walls are expected in the present structure due to the absence of mechanical compatibility between domains.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Flerov I. N., Gorev M. V., Aleksandrov K. S., Tressaud A., Fokina V. D.
Заглавие : Ferroelastic phase transitions in fluorides with cryolite and elpasolite structures
Место публикации : Crystallogr. Rep. - 2004. - Vol. 49, Is. 1. - P.100-107. - ISSN 1063-7745, DOI 10.1134/1.1643969
Примечания : Cited References: 43
Предметные рубрики: NUCLEAR MAGNETIC-RESONANCE
THERMODYNAMIC PROPERTIES
RB2KMIIIF6 ELPASOLITES
NEUTRON-DIFFRACTION
CRYSTALS
PEROVSKITES
DIAGRAM
SC
RB2KGAXSC1-XF6
SCATTERING
Аннотация: The ferroelastic phase transitions are investigated in several series of fluoride crystals belonging to the elpasolite and cryolite families (space group Fm (3) over barm) with the general formula A(2)BB'F-6. The influence of the size and shape of cations and anions on the entropy and the mechanism of structural distortions is discussed. (C) 2004 MAIK "Nauka/Interperiodica".
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gluck M., Kolovsky A. R., Korsch H. J.
Заглавие : Lifetime statistics for a Bloch particle in ac and dc fields
Место публикации : Phys. Rev. E: AMERICAN PHYSICAL SOC, 1999. - Vol. 60, Is. 1. - P247-258. - ISSN 1063-651X, DOI 10.1103/PhysRevE.60.247
Примечания : Cited References: 27
Предметные рубрики: DYNAMIC LOCALIZATION
QUANTUM
TRANSITION
SCATTERING
MATRICES
SYSTEMS
LADDER
STATES
ATOMS
LIGHT
Аннотация: We study the statistics of the Wigner delay time and resonance width for a Bloch particle in ac and de fields in the regime of quantum chaos. It is shown that after appropriate rescaling the distributions of these quantities have a universal character predicted by the random matrix theory of chaotic scattering. [s1063-651X(99)09907-9].
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Bulgakov E. N., Pichugin K. N., Sadreev A. F., Streda P., Seba P.
Заглавие : Hall-like effect induced by spin-orbit interaction
Место публикации : Phys. Rev. Lett.: AMERICAN PHYSICAL SOC, 1999. - Vol. 83, Is. 2. - P376-379. - ISSN 0031-9007, DOI 10.1103/PhysRevLett.83.376
Примечания : Cited References: 17
Предметные рубрики: BERRYS PHASE
CONDUCTANCE
SCATTERING
SPECTRUM
RINGS
Аннотация: We study the effect of spin-orbit interaction on the electron-transport properties of a cross-junction structure. It results in spin polarization of left and right outgoing electron waves. Consequently, the incoming electron wave of a certain polarization induces a voltage drop perpendicular to the direct current flow between the source and drain of the four-terminal cross structure investigated. The resulting Hall-like resistance is estimated to be of the order of 10(-3)-10(-2)h/e(2) for technologically feasible structures. The effect becomes more pronounced in the vicinity of resonances when the Hall-like resistance changes its sign as a function of the Fermi energy.
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gavriliuk A. G., Trojan I. A., Lyubutin I. S., Ovchinnikov S. G., Sarkissian V. A.
Заглавие : High-pressure magnetic properties and P-T phase diagram of iron borate
Место публикации : J. Exp. Theor. Phys.: AMER INST PHYSICS, 2005. - Vol. 100, Is. 4. - P688-696. - ISSN 1063-7761, DOI 10.1134/1.1926429
Примечания : Cited References: 24
Предметные рубрики: FEBO3 SINGLE-CRYSTALS
NUCLEAR-RESONANCE
BAND-STRUCTURE
TRANSITION
TEMPERATURE
SCATTERING
Ключевые слова (''Своб.индексиров.''): antiferromagnetic materials--diamonds--ferromagnetic materials--high pressure effects--low temperature effects--magnetic moments--magnetic properties--magnetization--phase diagrams--powders--single crystals--synchrotron radiation--diamond anvil cells--electronic transition--iron borate--nuclear forward scattering (nfs)--iron compounds
Аннотация: The high-pressure magnetic states of iron borate (FeBO3)-Fe-57 single-crystal and powder samples have been investigated in diamond anvil cells by nuclear forward scattering (NFS) of synchrotron radiation at different temperatures. In the low-pressure (0 < P < 46 GPa) antiferromagnetic phase, an increase of the Neel temperature from 350 to 595 K induced by pressure was found. At pressures 46-49 GPa, a transition from the antiferromagnetic to a new magnetic state with a weak magnetic moment (magnetic collapse) was discovered. It is attributed to the electronic transition in Fe3+ ions from the high-spin 3d(5) (S = 5/2, (6)A(1g)) to the low-spin (S = 1/2, T-2(2g)) state (spin crossover) due to the insulator-semiconductor-type transition with extensive suppression of strong d-d electron correlations. At low temperatures, NFS spectra of the high-pressure phase indicate magnetic correlations in the low-spin system with a magnetic ordering temperature of about 50 K. A tentative magnetic P-T phase diagram of FeBO3 is proposed. An important feature of this diagram is the presence of two triple points where magnetic and paramagnetic phases of the high-spin and low-spin states coexist. © 2005 Pleiades Publishing, Inc.
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Liu, Ji-Cai, Savchenko, Viktoriia, Kimberg V., Gel'mukhanov F., Odelius, Michael
Заглавие : High-resolution x-ray spectra of carbon monoxide reveal ultrafast dynamics induced by long UV pulse
Коллективы : RFBRRussian Foundation for Basic Research (RFBR) [19-29-12015]; National Science Foundation of ChinaNational Natural Science Foundation of China (NSFC) [11974108, 11574082]; Fundamental Research Funds for the Central UniversitiesFundamental Research Funds for the Central Universities [2021MS046]; European UnionEuropean Commission [860553]; Carl Tryggers Foundation [CTS18:285]; Helmholtz Virtual Institute [VI419]; Swedish Research CouncilSwedish Research CouncilEuropean Commission [VR 2019-03470, 2018-05973]
Место публикации : New J. Phys. - 2021. - Vol. 23, Is. 6. - Ст.063030. - ISSN 1367-2630, DOI 10.1088/1367-2630/ac0198
Примечания : Cited References: 47. - The reported study was funded by RFBR, project number 19-29-12015. J-CL thanks the support by the National Science Foundation of China under Grant Nos. 11974108, 11574082, and the Fundamental Research Funds for the Central Universities (No. 2021MS046). MO acknowledges funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skodowska-Curie Grant Agreement No. 860553 and the Carl Tryggers Foundation (contract CTS18:285). FG acknowledges also the support from the Helmholtz Virtual Institute VI419 'Dynamic Pathways in Multidimensional Landscapes'. VK acknowledges the Swedish Research Council (VR 2019-03470). The calculations were partially enabled by resources provided by the Swedish National Infrastructure for Computing (SNIC) partially funded by the Swedish Research Council through Grant Agreement No. 2018-05973
Предметные рубрики: VIBRATIONAL STRUCTURE
SCATTERING
RAMAN
CO
COLLAPSE
PROBE
Аннотация: In theoretical simulations of a UV + x-ray pump-probe (UVX-PP) setup, we show that frequency detuning of the pump UV pulse acts as a camera shutter by regulating the duration of the UVX-PP process. This two-photon absorption with long overlapping UV and x-ray pulses, allowing for high spectral resolution, thereby provides information about ultrafast dynamics of the nuclear wave packet without the requirement of ultrashort pulses and controlled delay times. In a case study of carbon monoxide, the calculated UVX-PP spectra of the O1s−12π1 and C1s−12π1 core-excited states show different vibrational profiles. The interference of intermediate vibrational states reveals details of nuclear dynamics in the UVX-PP process related to a variable duration time controlled by the UV detuning. Both O1s−12π1 and C1s−12π1 pump-probe channels display a splitting of the spectral profile, which however is associated with different physical mechanisms. At the O1s−12π1 resonance, the observed dispersive and non-dispersive spectral bands intersect and result in destructive interference.
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18.

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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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ignatchenko V. A., Tsikalov D. S.
Заглавие : Spectral properties of waves in superlattices with 2D and 3D inhomogeneities
Место публикации : J. Exp. Theor. Phys.: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2011. - Vol. 113, Is. 2. - P.232-244. - ISSN 1063-7761, DOI 10.1134/S1063776111080061
Примечания : Cited References: 24. - This study was supported in part by the program of the Presidium of the Russian Academy of Sciences (grant no. 27.1), Federal Targeted Program (State contract no. 02.740.11.0220), and Targeted Programs "Development of the Higher School Scientific Potential" in 2009-2010 and 2011 years.
Предметные рубрики: X-RAY REFLECTION
PERTURBED FIELDS
MULTILAYERS
SUSCEPTIBILITY
PROPAGATION
INTERFACES
SCATTERING
SYSTEM
Аннотация: We investigate the dynamic susceptibility and one-dimensional density of states in an initially sinusoidal superlattice containing simultaneously 2D phase inhomogeneities simulating correlated rough-nesses of superlattice interfaces and 3D amplitude inhomogeneities of the superlattice layer materials. The analytic expression for the averaged Green's function of the sinusoidal superlattice with two phase inhomogeneities is derived in the Bourret approximation. It is shown that the effect of increasing asymmetry in the peak heights of dynamic susceptibility at the Brillouin zone boundary of the superlattice, which was discovered earlier [15] upon an increase in root-mean-square (rms) fluctuations, also takes place upon an increase in the correlation wavenumber of inhomogeneities. However, the peaks in this case also become closer, and the width and depth of the gap in the density of states decrease thereby. It is shown that the enhancement of rms fluctuations of 3D amplitude inhomogeneities in a superlattice containing 2D phase inhomogeneities suppresses the effect of dynamic susceptibility asymmetry and leads to a slight broadening of the gap in the density of states and a decrease in its depth. Targeted experiments aimed at detecting the effects studied here would facilitate the development of radio-spectroscopic and optical methods for identifying the presence of inhomogeneities of various dimensions in multilayer magnetic and optical structures.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kagan M. Y., Val'kov V. V., Woelfle P.
Заглавие : Manifestation of the upper Hubbard band in the 2D Hubbard model at low electron density
Место публикации : Low Temp. Phys. - 2011. - Vol. 37, Is. 9-10. - P.834-839. - ISSN 1063-777X, DOI 10.1063/1.3670026; \b Физика низких температур
Примечания : Cited References: 31. - This work was supported by RFBR Grants No. 11-0200798 and 11-02-00741.
Предметные рубрики: 2-DIMENSIONAL FERMI GAS
LIQUID BEHAVIOR
SPECTRAL FUNCTIONS
TRANSITION METALS
SUPERCONDUCTIVITY
FERROMAGNETISM
DIMENSIONS
SCATTERING
STATE
Ключевые слова (''Своб.индексиров.''): electron density--electronic density of states--fermi liquid--green's function methods--hubbard model
Аннотация: We consider the 2D Hubbard model in the strong-coupling case (U W) and at low electron density (nd(2) ≪1). We find an antibound state as a pole in the two-particle T-matrix. The contribution of this pole in the self-energy reproduces a two-pole structure in the dressed one-particle Green-function similar to the Hubbard-I approximation. We also discuss briefly the Engelbrecht-Randeria mode which corresponds to the pairing of two holes below the bottom of the band for U W and low electron density. Both poles produce nontrivial corrections to Landau Fermi-liquid picture already at low electron density but do not destroy it in 2D.
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