Труды сотрудников института физики

/ M. Y. Kagan, V. V. Valkov // Low Temp. Phys. - 2011. - Vol. 37, Is. 1. - P. 69-82 ; Физика низких температур, DOI 10.1063/1.3552118. - Cited References: 62. - We thank A.S. Alexandrov, A.F. Andreev, M.A. Baranov, Yu. Bichkov, A.V. Chubukov, D.V. Efremov, A.S. Hewson, K.A. Kikoin, F.V. Kusmartsev, P. Nozieres, T.M. Rice, A.O. Sboychakov, P. Thalmeer, C.M. Varma, D. Vollhardt, P. Woelfle, A. Yaresko and, especially, P. Fulde, Yu. Kagan, K.I. Kugel, and N.V. Prokof'ev for many simulating discussions on this subject and acknowledge the financial support of RFBR grants # 08-02-00224 and 08-02-00212. M.Yu.K. is also grateful to the Leverhulme trust for a grant to visit Loughborough University, where this work was completed. . - ISSN 1063-777XРУБ Physics, Applied

Аннотация: We search for marginal Fermi-liquid behavior in the two-band Hubbard model with one narrow band. We consider the limit of low electron densities in the bands and strong intraband and interband Hubbard interactions. We analyze the influence of electron-polaron effects and other mechanisms for mass-enhancement (related to the momentum dependence of the self-energies) on the effective mass and scattering times of light and heavy components in the clean case (electron-electron scattering and no impurities). We find a tendency towards phase separation (towards negative partial compressibility of heavy particles) in the 3D case with a large mismatch between the densities of heavy and light bands in the strong coupling limit. We also find that for low temperatures and equal densities, the resistivity in a homogeneous state R(T) proportional to T-2 behaves as a Fermi-liquid in both 3D and 2D. For temperatures greater than the effective bandwidth for heavy electrons T W-h*, the coherence of the heavy component breaks down completely. The heavy particles move diffusively in the surrounding light particles. At the same time, light particles scatter on heavy particles as if on immobile (static) impurities. Under these conditions, the heavy component is marginal, while the light component is not. The resistivity approaches saturation for T W-h* in the 3D case. In 2D the resistivity has a maximum and a localization tail owing to weak-localization corrections of the Altshuler-Aronov type. This behavior of resistivity in 3D could be relevant for some uranium-based heavy-fermion compounds such as UNi2Al3 and in 2D, for some other mixed-valence compounds, possibly including layered manganites. We also consider briefly the superconductive (SC) instability in this model. The leading instability tends to p-wave pairing and is governed by an enhanced Kohn-Luttinger mechanism for SC at low electron densities. The critical temperature corresponds to the pairing of heavy electrons via polarization of the light electrons in 2D. (C) 2011 American Institute of Physics. [doi:10.1063/1.3552118]

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Держатели документа:
[Kagan, M. Yu.] Russian Acad Sci, PL Kapitza Phys Problems Inst, Moscow 119334, Russia
[Valkov, V. V.] Russian Acad Sci, LV Kirensky Phys Inst, Siberian Branch, Krasnoyarsk 660036, Russia
ИФ СО РАН
P.L.Kapitza Institute for Physical Problems of the Russian Academy of Sciences, 2 Kosygin St., Moscow 119334, Russian Federation
Kirensky Institute of Physics, Siberian Branch of the Russian Academy of Sciences, Akademgorodok, Krasnoyarsk 660036, Russian Federation

Доп.точки доступа:
Valkov, V. V.; Вальков, Валерий Владимирович

/ V. V. Valkov, D. M. Dzebisashvili // Phys. Solid State. - 1997. - Vol. 39, Is. 2. - P. 179-184, DOI 10.1134/1.1129779. - Cited References: 19 . - ISSN 1063-7834РУБ Physics, Condensed Matter

Аннотация: The distinctive characteristics of the de Haas-van Alphen effect in semimetals with antiferromagnetic long-range order are investigated theoretically. It is shown that the transition of the subsystem of localized spins from the canted antiferromagnetic phase to the ferromagnetic phase is accompanied by an abrupt change in the ''frequency'' of the magnetization oscillations of band carriers M-similar to. In the below-critical range of magnetic fields, M-similar to is not a function periodic in 1/H. Significantly, the additional contribution to the phase of the oscillatory factors is proportional to H-2 and is determined entirely by quantum fluctuations in the antiferromagnetic subsystem. (C) 1997 American Institute of Physics.

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Держатели документа:
L.V. Kirenskii Inst. of Phys., Siberian Br. Russ. Acad. of Sci., 660036 Krasnoyarsk, Russian Federation
ИФ СО РАН

Доп.точки доступа:
Dzebisashvili, D. M.; Дзебисашвили, Дмитрий Михайлович; Val'kov, V. V.

/ A. Furrer [et al.] // Solid State Commun. - 1992. - Vol. 82, Is. 6. - P. 443-446, DOI 10.1016/0038-1098(92)90746-V. - Cited References: 9 . - ISSN 0038-1098РУБ Physics, Condensed Matter

Аннотация: Neutron scattering experiments have been employed to study the spin-wave excitations and the critical behaviour of sublattice magnetization of a single crystal Bi2CuO4. Dispersion law for spin waves along the tetragonal axis of crystal is determined. There were found two branches of spin waves which are characterized by the energy gaps DELTA-1 congruent-to 1.7 meV and DELTA-2 congruent-to 4.0 meV, respectively. The value of critical exponent beta = 0.36 + 0.08 reflects the 3D character of the magnetic ordering in Bi2CuO4. Observed two spin-wave branches are described on the basis of the anisotropic tetragonal spin-Hamiltonian with four-sites exchange interaction.

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Держатели документа:
LV KIRENSKY PHYS INST,KRASNOYARSK 660036,USSR
ИФ СО РАН

Доп.точки доступа:
Furrer, A.; Fisher, P.; Roessli, B.; Petrakovskii, G. A.; Петраковский, Герман Антонович; Sablina, K. A.; Саблина, Клара Александровна; Valkov, V. V.; Вальков, Валерий Владимирович; Fedoseev, B.

/ V. V. VALKOV // Theor. Math. Phys. - 1988. - Vol. 76, Is. 1. - P. 766-772, DOI 10.1007/BF01029435. - Cited References: 20 . - ISSN 0040-5779РУБ Physics, Multidisciplinary + Physics, Mathematical


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Доп.точки доступа:
Val'kov, V. V.

/ V. V. Valkov, T. A. Valkova, S. G. Ovchinnikov // Phys. Status Solidi B. - 1987. - Vol. 142, Is. 1. - P. 255-263, DOI 10.1002/pssb.2221420126. - Cited References: 22 . - ISSN 0370-1972РУБ Physics, Condensed Matter


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Доп.точки доступа:
Valkova, T. A.; Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Val'kov, V. V.

/ V. V. VALKOV, T. A. VALKOVA // Theor. Math. Phys. - 1984. - Vol. 59, Is. 3. - P. 617-625, DOI 10.1007/BF01018202. - Cited References: 18 . - ISSN 0040-5779РУБ Physics, Multidisciplinary + Physics, Mathematical


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Доп.точки доступа:
VALKOVA, T. A.; Val'kov, V. V.

/ V. V. VALKOV, S. G. OVCHINNIKOV // Theor. Math. Phys. - 1982. - Vol. 50, Is. 3. - P. 306-313, DOI 10.1007/BF01016463. - Cited References: 32 . - ISSN 0040-5779РУБ Physics, Multidisciplinary + Physics, Mathematical


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Доп.точки доступа:
OVCHINNIKOV, S. G.; Овчинников, Сергей Геннадьевич; Val'kov, V. V.

/ V. V. Valkov, S. G. Ovchinnikov // Phys. Status Solidi B. - 1981. - Vol. 108, Is. 2. - P. 601-608, DOI 10.1002/pssb.2221080238. - Cited References: 13 . - ISSN 0370-1972РУБ Physics, Condensed Matter


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Доп.точки доступа:
Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Вальков, Валерий Владимирович

/ V. V. VALKOV, B. P. KHRUSTALEV // Zhurnal Eksperimentalnoi Teor. Fiz. - 1995. - Vol. 107, Is. 4. - P. 1221-1231. - Cited References: 18 . - ISSN 0044-4510РУБ Physics, Multidisciplinary


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Доп.точки доступа:
KHRUSTALEV, B. P.

/ V. V. Valkov, T. A. Valkova // Zhurnal Eksperimentalnoi Teor. Fiz. - 1991. - Vol. 99, Is. 6. - P. 1881-1897. - Cited References: 37 . - ISSN 0044-4510РУБ Physics, Multidisciplinary

Аннотация: A procedure is developed for a correct transition to the Bose representation for quantum SU(3) Hamiltonians. The analysis is carried out for a spin nematic by applying the indefinite metric formalism and pseudo-Hubbard operators. An important aspect of the theory is that the finiteness of the number of physical states is taken into account. This is attained by introducing and consistently taking into account the metric operator for which purpose a simple expression in terms of Bose operators is suggested. It is shown that in this approach the quantum Bose analog of the Hamiltonian is an Hermitian operator. This circumstance removes a number of principle contradictions which appeared previously on application of the Bose analog of the Hamiltonian derived by virtually identifying the Hubbard and pseudo-Hubbard operators and ignoring the finiteness of the number of physical states. The integral equations defining the chief characteristics of the system are obtained and solved analytically for the spin-nematic state of a magnet with S = 1 and by taking into account anharmonic effects. This permits one to write down in nonlinear theory explicit expressions for the two branches of the quantum excitation spectrum. The character of the renormalization of the spectrum parameters due to the presence of zero-point quantum oscillations is studied. The renormalization of the critical field on transition of the system from the spin nematic state is calculated analytically.

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Доп.точки доступа:
Valkova, T. A.; Вальков, Валерий Владимирович

/ V. V. Valkov, T. A. Valkova // JETP Letters. - 1990. - Vol. 52, Is. 11. - P. 589-592. - Cited References: 6 . - ISSN 0021-3640РУБ Physics, Multidisciplinary

Аннотация: It is shown in a nonlinear theory that the quantum spectrum of excitations becomes analogous to the spectrum of excitations of a quantum Bose liquid in the case of a highly anisotropic ferromagnet, with a large number of interacting quasiparticles.

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Доп.точки доступа:
Valkova, T. A.; Val'kov, V. V.

/ V. V. VALKOV, B. V. FEDOSEEV // Fiz. Tverd. Tela. - 1990. - Vol. 32, Is. 12. - P. 3522-3530. - Cited References: 13 . - ISSN 0367-3294РУБ Physics, Condensed Matter


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Доп.точки доступа:
FEDOSEEV, B. V.

/ V. V. VALKOV, S. G. OVCHINNIKOV, O. G. PETRAKOVSKII // Fiz. Tverd. Tela. - 1990. - Vol. 32, Is. 7. - P. 2001-2003. - Cited References: 5 . - ISSN 0367-3294РУБ Physics, Condensed Matter


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Доп.точки доступа:
Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Petrakovskii, G. A.; Петраковский, Герман Антонович; Val'kov, V. V.

/ V. V. VALKOV, G. N. MATSULEVA, S. G. OVCHINNIKOV // Fiz. Tverd. Tela. - 1989. - Vol. 31, Is. 6. - P. 60-68. - Cited References: 29 . - ISSN 0367-3294РУБ Physics, Condensed Matter


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Доп.точки доступа:
MATSULEVA, G. N.; Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Val'kov, V. V.

/ V. V. VALKOV // Zhurnal Eksperimentalnoi Teor. Fiz. - 1989. - Vol. 95, Is. 1. - P. 192-210. - Cited References: 25 . - ISSN 0044-4510РУБ Physics, Multidisciplinary


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/ V. V. VALKOV, S. G. OVCHINNIKOV, O. G. PETRAKOVSKII // Fiz. Tverd. Tela. - 1988. - Vol. 30, Is. 10. - P. 3044-3047. - Cited References: 6 . - ISSN 0367-3294РУБ Physics, Condensed Matter


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Доп.точки доступа:
Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Petrakovskii, G. A.; Петраковский, Герман Антонович; Val'kov, V. V.

/ V. V. VALKOV, G. N. MATSULYEVA // Zhurnal Eksperimentalnoi Teor. Fiz. - 1988. - Vol. 94, Is. 1. - P. 217-226. - Cited References: 35 . - ISSN 0044-4510РУБ Physics, Multidisciplinary


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Доп.точки доступа:
MATSULYEVA, G. N.

/ V. V. Valkov, T. A. Valkova // Fiz. Nizk. Temp. - 1985. - Vol. 11, Is. 9. - P. 951-959. - Cited References: 33 . - ISSN 0132-6414РУБ Physics, Applied


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Доп.точки доступа:
Valkova, T. A.; Val'kov, V. V.

/ V. V. VALKOV, T. A. VALKOVA, S. G. OVCHINNIKOV // Zhurnal Eksperimentalnoi Teor. Fiz. - 1985. - Vol. 88, Is. 2. - P. 550-561. - Cited References: 31 . - ISSN 0044-4510РУБ Physics, Multidisciplinary


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Доп.точки доступа:
VALKOVA, T. A.; Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Val'kov, V. V.

/ E. V. BABKIN [и др.] // Fiz. Tverd. Tela. - 1983. - Vol. 25, Is. 6. - P. 1896-1898. - Cited References: 4 . - ISSN 0367-3294РУБ Physics, Condensed Matter


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Доп.точки доступа:
BABKIN, E. V.; CHERKUNOVA, N. G.; Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Valkov, V. V.; Val'kov, V. V.