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1.


    Makarov, I. A.
    Dependence of the critical temperature of high-temperature cuprate superconductors on hoppings and spin correlations between CuO2 planes / I. A. Makarov, S. G. Ovchinnikov, E. I. Shneider // J. Exp. Theor. Phys. - 2012. - Vol. 114, Is. 2. - P. 329-342, DOI 10.1134/S1063776112020264. - Cited References: 73. - This study was supported in part by the Presidium of the Russian Academy of Sciences (program "Quantum Physics of Condensed Media," project no. 18.7), jointly by the Siberian and Ural branches of the Russian Academy of Sciences (integration projects project no. 40), the Russian Foundation for Basic Research (project no. 09-02-00127), the Presidential Program in Support of Young Scientists in Russia (project no. MK-1683.2010.2), and the federal target program "Specialists" (project no. P891). One of the authors (E.I.Sh.) gratefully acknowledges support from the nonprofit Dynasty foundation. . - ISSN 1063-7761
РУБ Physics, Multidisciplinary
Рубрики:
T-J MODEL
   BAND HUBBARD-MODEL

   SINGLE-CRYSTALS

   TRANSITION-TEMPERATURE

   FERMI-SURFACE

   DOPING DEPENDENCE

   THERMAL-EXPANSION

   COPPER OXIDES

   ANISOTROPY

   LA2-XSRXCUO4

Аннотация: The influence of interlayer hoppings on the superconducting transition temperature (T c) in bilayer cuprates has been studied. The parameter of hopping between layers is expressed as t ⊥(k) = t ⊥(cos(k x ) − cos(k y ))2 and treated as a small perturbation for the states of two CuO2 planes described by the t-t′-t″-J* model. In the generalized mean field approximation for dx2−y2{d_{{x. } - {y. }}} symmetry of the superconducting gap, neither the interlayer hopping or exchange interaction, nor the pair hopping between CuO2 layers provides an additional mechanism of Cooper pair formation or an increase in T c. In the concentration dependence of T c, the bilayer splitting of the upper Hubbard band of quasi-holes is manifested as two peaks with temperatures slightly lower than the maximum T c for a single-layer cuprate. Interlayer antiferromagnetic spin correlations suppress bilayer splitting.

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Публикация на русском языке Макаров, Илья Анатольевич. Зависимость критической температуры высокотемпературных сверхпроводников от перескоков и спиновых корреляций между CuO2-плоскостями [Текст] / И. А. Макаров, С. Г. Овчинников, Е. И. Шнейдер // Журн. эксперим. и теор. физ. : Наука, 2012. - Т. 141 Вып. 2. - С. 372-386

Держатели документа:
[Makarov, I. A.
Ovchinnikov, S. G.
Shneider, E. I.] Russian Acad Sci, Siberian Branch, Kirensky Inst Phys, Krasnoyarsk 660036, Russia
[Makarov, I. A.
Ovchinnikov, S. G.] Siberian Fed Univ, Krasnoyarsk 660041, Russia
[Shneider, E. I.] Reshetnikov Siberian State Aerosp Univ, Krasnoyarsk 660014, Russia

Доп.точки доступа:
Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Shneider, E. I.; Шнейдер, Елена Игоревна; Макаров, Илья Анатольевич
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2.


    Nikolaev, S. V.
    Effect of hole doping on the electronic structure and the Fermi surface in the Hubbard model within norm-conserving cluster pertubation theory / S. V. Nikolaev, S. G. Ovchinnikov // J. Exp. Theor. Phys. - 2012. - Vol. 114, Is. 1. - P. 118-131, DOI 10.1134/S1063776111150143. - Cited References: 51. - This study was supported financially by the Russian Foundation for Basic Research (project nos. 10-02-90725-mob_st and 09-02-00127), Program 18.7 of the Presidium of the Russian Academy of Sciences, the Federal Target Program "Personnel" (state contract no. P891), and the integrated project no. 40 of the Siberian Branch of the Russian Academy of Sciences. . - ISSN 1063-7761
РУБ Physics, Multidisciplinary
Рубрики:
HIGH-TEMPERATURE SUPERCONDUCTORS
   NARROW ENERGY-BANDS

   CORRELATED ELECTRONS

   PSEUDOGAP

   EVOLUTION

   La2-XSRXCuO4

   INSULATOR

Аннотация: The concentration dependences of the band structure, spectral weight, density of states, and Fermi surface in the paramagnetic state are studied in the Hubbard model within cluster pertubation theory with 2 x 2 clusters. Representation of the Hubbard X operators makes it possible to control conservation of the spectral weight in constructing cluster perturbation theory. The calculated value of the ground-state energy is in good agreement with the results obtained using nonperturbative methods such as the quantum Monte Carlo method, exact diagonalization of a 4 x 4 cluster, and the variational Monte Carlo method. It is shown that in the case of hole doping, the states in the band gap (in-gap states) lie near the top of the lower Hubbard band for large values of U and near the bottom of the upper band for small U. The concentration dependence of the Fermi surface strongly depends on hopping to second (t') and third (t '') neighbors. For parameter values typical of HTSC cuprates, the existence of three concentration regions with different Fermi surfaces is demonstrated. It is shown that broadening of the spectral electron density with an energy resolution typical of contemporary ARPES leads to a pattern of arcs with a length depending on the concentration. Only an order-of-magnitude decrease in the linewidth makes it possible to obtain the true Fermi surface from the spectral density. The kinks associated with strong electron correlations are detected in the dispersion relation below the Fermi level.

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Публикация на русском языке Николаев, Сергей Викторович. Влияние дырочного допирования на электронную структуру и поверхность ферми в модели хаббарда в рамках кластерной теории возмущений с контролируемым спектральным весом [Текст] / С. В. Николаев, С. Г. Овчинников // Журн. эксперим. и теор. физ. : Наука, 2012. - Т. 141 Вып. 1. - С. 135-150

Держатели документа:
[Nikolaev, S. V.
Ovchinnikov, S. G.] Russian Acad Sci, Kirensky Inst Phys, Siberian Branch, Krasnoyarsk 660036, Russia
[Nikolaev, S. V.] Dostoevsky State Univ, Omsk 644077, Russia
[Ovchinnikov, S. G.] Siberian Fed Univ, Krasnoyarsk 660041, Russia

Доп.точки доступа:
Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Николаев, Сергей Викторович
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3.


   
    Coupling of Hubbard fermions with phonons in La2 CuO4: A combined study using density-functional theory and the generalized tight-binding method / E. I. Shneyder [et al.] // J. Alloys Compd. - 2015. - Vol. 648. - P. 258-264, DOI 10.1016/j.jallcom.2015.05.150. - Cited References: 60. - We acknowledge the stimulating discussions with V.V. Val'kov, D.M. Dzebisashvilly, M.M. Korshunov and I.S. Sandalov. E.I.S. and S.G.O. are thankful to the Russian Science Foundation (project No. 14-12-00061) for the support of the research given in Sections 2, 6 and 7. E.E.K. and I.A.N. are thankful to the State Contract No. 0389-2014-0001 and RFBR grant No. 14-02-00065 for the support of the research given in Section 5. Financial support of the research given in Sections 3 and 4 by the Austrian Federal Government (in particular from Bundesministerium fur Verkehr, Innovation und Technologie and Bundesministerium fur Wissenschaft, Forschung und Wirtschaft) represented by Osterreichische Forschungsforderungsgesellschaft mbH and the Styrian and the Tyrolean Provincial Government, represented by Steirische Wirtschaftsforderungsgesellschaft mbH and Standortagentur Tirol, within the framework of the COMET Funding Programme is gratefully acknowledged by C.D. and J.S. . - ISSN 0925-8388
РУБ Chemistry, Physical + Materials Science, Multidisciplinary + Metallurgy & Metallurgical Engineering
Рубрики:
MEAN-FIELD THEORY
   LINEAR-RESPONSE THEORY

   CUPRATE SUPERCONDUCTORS

   ELECTRONIC-STRUCTURE

   CORRELATED SYSTEMS

   LATTICE-DYNAMICS

   BAND-STRUCTURE

   LA2CUO4

   MODEL

   LA2-XSRXCUO4

Кл.слова (ненормированные):
High-temperature superconductivity -- Electron-phonon coupling -- Density-functional theory -- Generalized tight-binding approach
Аннотация: We present results for the electron-phonon interaction of the Γ-point phonons in the tetragonal high-temperature phase of La2 CuO4 obtained from a hybrid scheme, combining density-functional theory (DFT) with the generalized tight-binding approach. As a starting point, eigenfrequencies and eigenvectors for the Γ-point phonons are determined from DFT within the frozen phonon approach utilizing the augmented plane wave + local orbitals method. The so obtained characteristics of electron-phonon coupling are converted into parameters of the generalized tight-binding method. This approach is a version of cluster perturbation theory and takes the strong on-site electron correlations into account. The obtained parameters describe the interaction of phonons with Hubbard fermions which form quasiparticle bands in strongly correlated electron systems. As a result, it is found that the Γ-point phonons with the strongest electron-phonon interaction are the A2u modes (236 cm-1, 131 cm-1 and 476 cm-1). Finally it is shown, that the single-electron spectral-weight redistribution between different Hubbard fermion quasiparticles results in a suppression of electron-phonon interaction which is strongest for the triplet Hubbard band with z oriented copper and oxygen electrons. © 2015 Elsevier B.V. All rights reserved.

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Держатели документа:
Kirensky Institute of Physics SB RAS, Akademgorodok 50, Bld. 38, Krasnoyarsk, Russian Federation
Reshetnev Siberian State Aerospace University, Krasnoyarsk, Russian Federation
Materials Center Leoben Forschung GmbH, Rosegger-Stra?e 18, Leoben, Austria
Institute of Electrophysics UB RAS, Amundsena Str. 106, Yekaterinburg, Russian Federation
Physics Department and IRIS Adlershof, Humboldt-Universita¨t zu Berlin, Zum Großen Windkanal 6, Berlin, Germany

Доп.точки доступа:
Shneyder, E. I.; Шнейдер, Елена Игоревна; Spitaler, J.; Kokorina, E. E.; Nekrasov, I. A.; Gavrichkov, V. A.; Гавричков, Владимир Александрович; Draxl, C.; Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич
}
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4.


    Ovchinnikov, S. G.
    The Interplay of Phonon and Magnetic Mechanism of Pairing in Strongly Correlated Electron System of High-T-c Cuprates / S. G. Ovchinnikov, E. I. Shneyder // J. Supercond. Nov. Magn. - 2010. - Vol. 23, Is. 5. - P. 733-736, DOI 10.1007/s10948-009-0633-z. - Cited References: 26. - This work is supported by the Presidium RAS program N 7 "Quantum physics of condensed matter," the integration project SORAN-UrORAN N 40, and the RFFI Grant 09-02-00127. . - ISSN 1557-1939
РУБ Physics, Applied + Physics, Condensed Matter
Рубрики:
PHASE-TRANSITIONS
   OXIDE SUPERCONDUCTORS

   SYMMETRY

   COPPER

   MODEL

   BAND

   BI2SR2CACU2O8+DELTA

   LA2-XSRXCUO4

   PB

Кл.слова (ненормированные):
High-T-c superconductivity -- Strong correlated electron systems -- Mechanisms of superconducting pairing -- High-T c superconductivity -- Mechanisms of superconducting pairing -- Strong correlated electron systems -- Ab initio -- Buckling mode -- Correlated electron systems -- Critical temperatures -- Cuprates -- Fitting parameters -- High-T -- Isotope effect -- Low energies -- Magnetic mechanisms -- Order of magnitude -- Phonon mode -- Strongly correlated electron system -- Strongly correlated electrons -- Superconducting pairing -- Superconductivity mechanism -- Type theory -- Buckling -- Copper compounds -- Electrons -- Isotopes -- Magnetic materials -- Phonons -- Superconductivity -- Superconducting magnets
Аннотация: We consider magnetic mechanism of superconducting pairing in the effective low energy t - t' - t '' - J* model with all parameters calculated ab initio. Interaction of strongly correlated electrons with different phonon modes is also incorporated. In a BCS type theory, the d(x2-y2) gap is given by a sum of magnetic and phonon contributions. The main contribution to the only fitting parameter G is determined by a competition of the breathing and buckling modes. Fitting the parameter G from the isotope effect, we obtain that magnetic and phonon contributions to the critical temperature T-c work together and are of the same order of magnitude.

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Держатели документа:
[Ovchinnikov, S. G.
Shneyder, E. I.] Russian Acad Sci, LV Kirensky Phys Inst, Siberian Branch, Krasnoyarsk 660036, Russia
[Ovchinnikov, S. G.] Siberian Fed Univ, Krasnoyarsk 660041, Russia
[Shneyder, E. I.] Reshetnev Siberian State Aerosp Univ, Krasnoyarsk 660014, Russia
ИФ СО РАН
L.V. Kirensky Institute of Physics, Siberian Branch, Russian Academy of Sciences, 660036 Krasnoyarsk, Russian Federation
Siberian Federal University, 660041 Krasnoyarsk, Russian Federation
Reshetnev Siberian State Aerospace University, 660014 Krasnoyarsk, Russian Federation

Доп.точки доступа:
Shneyder, E. I.; Шнейдер, Елена Игоревна; Овчинников, Сергей Геннадьевич
}
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5.


   
    The Fermi surface and the role of electronic correlations in Sm2-xCexCuO4 / M. M. Korshunov [et al.] // J. Phys.: Condens. Matter. - 2010. - Vol. 22, Is. 1. - Ст. 15701, DOI 10.1088/0953-8984/22/1/015701. - Cited References: 35. - We would like to thank A A Kordyuk and I Eremin for useful discussions. The authors acknowledge support from RFBR (grants 08-02-00021, 10-02-00662, 08-02-91200 and 07-02-00226), the RAS programs on 'Low temperature quantum phenomena', 'Quantum physics of condensed matter' and 'Strongly correlated electrons solids', President of Russia (grants MK-614.2009.2 (IN) and MK-3227.2008.2 (ZP)), Scientific School (grant SS-1929.2008.2), Interdisciplinary UB-SB RAS project, Dynasty Foundation (ZP) and Russian Science Support Foundation (IN). . - ISSN 0953-8984
РУБ Physics, Condensed Matter
Рубрики:
T-C SUPERCONDUCTOR
   IN-GAP STATES

   SPIN CORRELATIONS

   BAND

   LA2-XSRXCUO4

   EXCITATIONS

   TRANSITION

   EVOLUTION

   SM2CUO4

   OXIDES

Кл.слова (ненормированные):
Antiferromagnetics -- Doping evolution -- Electron-doped -- Electronic correlation -- Emery model -- Experimental data -- Generalized tight bindings -- High-T -- Hybrid scheme -- Magnetic orders -- Spin-liquid -- Tight binding model -- Two-regime -- Antiferromagnetism -- Cerium -- Cerium compounds -- Copper oxides -- Corundum -- Doping (additives) -- Fermi surface -- Fermions -- Tin -- Surfaces
Аннотация: Using a LDA + GTB (local density approximation + generalized tight-binding) hybrid scheme we investigate the band structure of the electron-doped high-T-c material Sm2-xCexCuO4. Parameters of the minimal tight-binding model for this system (the so-called three-band Emery model) were obtained within the NMTO (Nth-order muffin-tin orbital) method. The doping evolution of the dispersion and the Fermi surface in the presence of electronic correlations was investigated in two regimes of magnetic order: short-range (spin-liquid) and long-range (antiferromagnetic metal). Each regime is characterized by the specific topologies of the Fermi surfaces and we discuss their relation to recent experimental data.

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Держатели документа:
[Korshunov, M. M.] Max Planck Inst Phys Komplexer Syst, D-01187 Dresden, Germany
[Korshunov, M. M.
Zakharova, E. V.
Ovchinnikov, S. G.] Russian Acad Sci, Siberian Branch, LV Kirensky Phys Inst, Krasnoyarsk 660036, Russia
[Nekrasov, I. A.] Russian Acad Sci, Inst Electrophys, Ekaterinburg 620016, Russia
[Pchelkina, Z. V.] Russian Acad Sci, Inst Met Phys, Ekaterinburg 620219, Russia
[Ovchinnikov, S. G.] Siberian Fed Univ, Krasnoyarsk 660041, Russia
ИФ СО РАН
Max-Planck-Institut fur Physik Komplexer Systeme, D-01187 Dresden, Germany
L v Kirensky Institute of Physics, Siberian Branch, Russian Academy of Sciences, Krasnoyarsk 660036, Russian Federation
Institute for Electrophysics, Russian Academy of Sciences, Ekaterinburg 620016, Russian Federation
Institute for Metal Physics, Russian Academy of Sciences, Ekaterinburg 620219, Russian Federation
Siberian Federal University, Krasnoyarsk 660041, Russian Federation

Доп.точки доступа:
Korshunov, M. M.; Коршунов, Максим Михайлович; Zakharova, E. V.; Nekrasov, I. A.; Pchelkina, Z. V.; Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич
}
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6.


    Ovchinnikov, S. G.
    Temperature evolution of spin-polaron in-gap states in undoped antiferromagnetic cuprates / S. G. Ovchinnikov, M. M. Korshunov, E. V. Zakharova // Phys. Solid State. - 2008. - Vol. 50, Is. 8. - P. 1401-1406, DOI 10.1134/S1063783408080027. - Cited References: 26. - This work was supported by the Russian Foundation for Basic Research (project nos. 06-02-16100 and 0602- 90537-BNTS), the Presidium of the Russian Academy of Sciences (program "Quantum Macrophysics"), and INTAS (YS grant no. 05-109-4891). . - ISSN 1063-7834
РУБ Physics, Condensed Matter
Рубрики:
J MODEL
   LA2-XSRXCUO4

   SUPERCONDUCTORS

   BAND

Аннотация: The temperature evolution of in-gap states created by the spin polaron effect and located within the gap with charge transfer between the valence and conduction bands is studied for the case of strong electron correlations using the t-t'-t ''-J model of antiferromagnetic undoped cuprates. The effect of temperature is taken into account by temperature renormalization of the magnon concentration, which is calculated using the Heisenberg model with inclusion of weak interlayer exchange and weak in-plane spin anisotropy, and by introducing a Lorentzian with a temperature-dependent half-width in the form corresponding to the marginal Fermi liquid model. With increasing temperature, the spectral weight of the in-gap state, which is proportional to the magnon concentration, grows leading to an increased intensity of the corresponding peak of the spectral function in all points of the Brillouin zone. At points (pi/2, pi/2) and (pi, 0), the main peak is approached by the satellite peak related to the in-gap band and, at points (0, 0) and (pi, pi), the peaks move away from each other.

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Публикация на русском языке Овчинников, Сергей Геннадьевич. Температурная зависимость спин-поляронных внутрищелевых состояний в недопированных антиферромагнитных купратах [Текст] / С. Г. Овчинников, М. М. Коршунов, Е. В. Захарова // Физ. тверд. тела. - 2008. - Т. 50 Вып. 8. - С. 1349-1354

Держатели документа:
[Ovchinnikov, S. G.
Korshunov, M. M.
Zakharova, E. V.] Russian Acad Sci, LV Kirensky Phys Inst, Siberian Div, Krasnoyarsk 660036, Russia
[Korshunov, M. M.] Max Planck Inst Phys Komplexen Syst, D-01187 Dresden, Germany
ИФ СО РАН
Kirensky Institute of Physics, Siberian Division, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk 660036, Russian Federation
Max-Planck Institut fur Physik Komplexen Systeme, Dresden D-01187, Germany

Доп.точки доступа:
Korshunov, M. M.; Коршунов, Максим Михайлович; Zakharova, E. V.; Овчинников, Сергей Геннадьевич
}
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7.


   
    Hybrid LDA and generalized tight-binding method for electronic structure calculations of strongly correlated electron systems / M. M. Korshunov [et al.] // Phys. Rev. B. - 2005. - Vol. 72, Is. 16. - Ст. 165104, DOI 10.1103/PhysRevB.72.165104. - Cited References: 82 . - ISSN 1098-0121
РУБ Physics, Condensed Matter
Рубрики:
T-J MODEL
   DENSITY-FUNCTIONAL CALCULATION

   NARROW ENERGY BANDS

   MEAN-FIELD THEORY

   COULOMB INTERACTIONS

   FERMION SYSTEMS

   COPPER OXIDES

   SUPERCONDUCTORS

   LA2-XSRXCUO4

   OXYGEN

Аннотация: A hybrid scheme for the electronic structure calculations of strongly correlated electron systems is proposed. The ab initio local density approximation calculation is used to construct the Wannier functions and obtain single electron and Coulomb parameters of the multiband Hubbard-type model. In strong correlation regime the electronic structure within multiband Hubbard model is calculated by the generalized tight-binding method, which combines the exact diagonalization of the model Hamiltonian for a small cluster (unit cell) with perturbation treatment of the intercluster hopping and interactions. For undoped La2CuO4 and Nd2CuO4 this scheme results in charge transfer insulators with correct values of gaps and dispersions of bands in agreement with the angle-resolved photoemission data.

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Держатели документа:
Russian Acad Sci, LV Kirensky Phys Inst, Siberian Branch, Krasnoyarsk 660036, Russia
Russian Acad Sci, Inst Met Phys, Ural Div, Ekaterinburg 620219, Russia
ИФ СО РАН
L.V. Kirensky Institute of Physics, Siberian Branch of Russian Academy of Sciences, 660036 Krasnoyarsk, Russian Federation
Institute of Metal Physics, Russian Academy of Sciences-Ural Division, 620219 Yekaterinburg GSP-170, Russian Federation

Доп.точки доступа:
Korshunov, M. M.; Коршунов, Максим Михайлович; Gavrichkov, V. A.; Гавричков, Владимир Александрович; Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Nekrasov, I. A.; Pchelkina, Z. V.; Anisimov, V. I.
}
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8.


   
    Prediction of the in-gap states above the top of the valence band in undoped insulating cuprates due to the spin-polaron effect / S. G. Ovchinnikov [et al.] // J. Phys.: Condens. Matter. - 2004. - Vol. 16, Is. 8. - P. L93-L100, DOI 10.1088/0953-8984/16/8/L04. - Cited References: 25 . - ISSN 0953-8984
РУБ Physics, Condensed Matter
Рубрики:
ELECTRONIC-STRUCTURE
   LA2-XSRXCUO4

   MODEL

   ANTIFERROMAGNETISM

   SPECTRA

   OXIDES

Кл.слова (ненормированные):
Quasiparticle band structure -- Spin-polaron effect -- Antiferromagnetic materials -- Approximation theory -- Doping (additives) -- Electronic structure -- Hamiltonians -- Insulation -- Magnetic fields -- Strontium compounds -- Thermal effects -- Lanthanum compounds
Аннотация: In the framework of the generalized tight binding method we have calculated the quasiparticle band structure and the spectral functions of the undoped cuprates such as La2CuO4, Sr2CUO2Cl2 etc. Due to spin fluctuations the in-gap state appears above the top of the valence band in the undoped antiferromagnetic insulator similar to in-gap states induced by hole doping. In the ARPES experiments the in-gap states can be detected as weak low energy satellites.

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Держатели документа:
Russian Acad Sci, Siberian Branch, LV Kirensky Phys Inst, Krasnoyarsk 660036, Russia
ИФ СО РАН
L V Kirensky Institute of Physics, Siberian Branch, Russian Academy of Science, Krasnoyarsk, 660036, Russian Federation

Доп.точки доступа:
Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Borisov, A. A.; Gavrichkov, V. A.; Гавричков, Владимир Александрович; Korshunov, M. M.; Коршунов, Максим Михайлович
}
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9.


   
    Effective parameters of the band dispersion in n-type high-T-c superconductors / M. M. Korshunov [et al.] // Physica C. - 2004. - Vol. 402, Is. 4. - P. 365-370, DOI 10.1016/j.physc.2003.10.017. - Cited References: 32 . - ISSN 0921-4534
РУБ Physics, Applied
Рубрики:
DOPED CUPRATE SUPERCONDUCTORS
   TIGHT-BINDING METHOD

   QUASI-PARTICLES

   COPPER OXIDES

   LA2-XSRXCUO4

   SYMMETRY

   MODEL

   EVOLUTION

   ORDER

Кл.слова (ненормированные):
high-T-c superconductivity -- electronic correlations -- electron-doped cuprates -- Electron-doped cuprates -- Electronic correlations -- High-Tc superconductivity -- Approximation theory -- Atomic physics -- Band structure -- Binding energy -- Charge transfer -- Correlation methods -- Doping (additives) -- Electronic structure -- Hamiltonians -- Mathematical models -- Mathematical operators -- Oxide superconductors -- Perturbation techniques -- Photoelectron spectroscopy -- Atomic orbitals -- Conduction band -- Electron doped cuprates -- Electron spins -- Valence band -- High temperature superconductors
Аннотация: The electronic structure of electron-doped cuprates is discussed in the regions of small and optimal doping. For optimal doping we obtain the parameters from a simple tight-binding analysis by fitting ARPES data, and for small doping we study the band structure by the generalized tight-binding method that takes strong electronic correlations into account explicitly. This method has also reproduced well the ARPES data for small doping. The effective low-energy Hamiltonian is the t-t'-J model with hopping parameters t and t'. We compare both methods and find very good agreement for the value of t while t' is different because it is caused by the different contribution of the short-range spin correlations. (C) 2003 Elsevier B.V. All rights reserved.

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Держатели документа:
Free Univ Berlin, Inst Theoret Phys, D-14195 Berlin, Germany
Russian Acad Sci, LV Kirensky Phys Inst, Siberian Branch, Krasnoyarsk 660036, Russia
ИФ СО РАН
L.V. Kirensky Institute of Physics, Siberian Branch, Russian Academy of Science, Krasnoyarsk 660036, Russian Federation
Inst. fur Theoretische Physik, Freie Universitat Berlin, Arnimallee 14, D-14195 Berlin, Germany

Доп.точки доступа:
Korshunov, M. M.; Коршунов, Максим Михайлович; Gavrichkov, V. A.; Гавричков, Владимир Александрович; Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Manske, D.; Eremin, I.
}
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10.


   
    Parameters of the effective singlet-triplet model for band structure of high-T-c cuprates by alternative approaches / M. M. Korshunov [et al.] // J. Exp. Theor. Phys. - 2004. - Vol. 99, Is. 3. - P. 559-565, DOI 10.1134/1.1809685. - Cited References: 48 . - ISSN 1063-7761
РУБ Physics, Multidisciplinary
Рубрики:
DENSITY-FUNCTIONAL CALCULATION
   TIGHT-BINDING METHOD

   COPPER OXIDES

   ENERGY-BANDS

   SUPERCONDUCTORS

   HOLE

   LA2-XSRXCUO4

   PLANE

   SR2CUO2CL2

   INSULATORS

Кл.слова (ненормированные):
Band structure -- Carbon dioxide lasers -- Copper oxides -- Doping (additives) -- Parameter estimation -- Electron systems -- Generalized tight binding (GTB) -- Parameters extraction -- Singlet triplet model -- Technetium compounds
Аннотация: We consider the problem of determining the parameters for high-T-c superconducting copper oxides. Alternative approaches, the ab initio LDA and LDA + U calculations and the generalized tight-binding (GTB) method for strongly correlated electron systems, are used to calculate hopping and exchange parameters of the effective singlet-triplet model for the CuO2 layer. The resulting parameters are in remarkably good agreement with each other and with parameters extracted from experiment. This set of parameters is proposed for proper quantitative description of the physics of hole-doped high-T-c cuprates in the framework of effective models. (C) 2004 MAIK "Nauka / Interperiodica".

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Держатели документа:
Russian Acad Sci, Kirensky Inst Phys, Siberian Div, Krasnoyarsk 660036, Russia
Russian Acad Sci, Inst Met Phys, Ural Div, Ekaterinburg 620219, Russia
ИФ СО РАН
Kirensky Institute of Physics, Siberian Division, Russian Academy of Sciences, Krasnoyarsk, 660036, Russian Federation
Institute of Metal Physics, Ural Division, Russian Academy of Sciences, Ekaterinburg, 620219, Russian Federation

Доп.точки доступа:
Korshunov, M. M.; Коршунов, Максим Михайлович; Gavrichkov, V. A.; Гавричков, Владимир Александрович; Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Pchelkina, Z. V.; Nekrasov, I. A.; Korotin, M. A.; Anisimov, V. I.
}
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11.


    Gavrichkov, V. A.
    The band structure of n-type cuprate superconductors with the T '(T) structure taking into account strong electron correlation / V. A. Gavrichkov, S. G. Ovchinnikov // J. Exp. Theor. Phys. - 2004. - Vol. 98, Is. 3. - P. 556-564, DOI 10.1134/1.1705708. - Cited References: 18. - This work was financially supported by the Russian Foundation for Basic Research (project no. 03-02-16124), RFFI-KKFN “Eniseœ” (project no. 02-02-97705), INTAS (project no. 01-0654), integration program of URO and Siberian Division, Russian Academy of Sciences . - ISSN 1063-7761
РУБ Physics, Multidisciplinary
Рубрики:
QUASI-PARTICLES
   COPPER OXIDES

   TEMPERATURE

   LA2-XSRXCUO4

   ND2-XCEXCUO4

   EVOLUTION

   MOMENTS

Кл.слова (ненормированные):
Dielectric properties -- Electric conductance -- Electron transitions -- Electronic structure -- Fermi level -- Phase diagrams -- Semiconductor doping -- Conduction bands -- Electron correlation -- Spectral density -- Superconducting materials
Аннотация: The spectral density, dispersion relations, and the position of the Fermi level for n-doped compositions based on NCO and LCO were calculated within the framework of the generalized tight binding method. As distinguished from LCO, the dielectric gap in NCO is nonlinear in character. We observe a virtual level both at the bottom of the conduction band and at the top of the valence band in both compounds. However, its position corresponds to the extreme bottom of the conduction band in LCO and is 0.1 - 0.2 eV above the bottom in NCO. This explains why we observe Fermi level pinning in n-LCO as the concentration of the doping component grows and reproduce its absence in NCCO at low doping values. We also found both compositions to be unstable in a narrow concentration range with respect to a nonuniform charge density distribution. The relation between the phase diagram for NCCO and the calculated electronic structure is discussed. (C) 2004 MAIK "Nauka/Interperiodica".

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Публикация на русском языке Гавричков, Владимир Александрович. Зонная структура купратных сверхпроводников n-типа с T'(T)-структурой при учете сильных электронных корреляций [Текст] / В. А. Гавричков, С. Г. Овчинников // Журн. эксперим. и теор. физ. - 2004. - Т. 125 Вып. 3. - С. 630-639

Держатели документа:
Russian Acad Sci, Siberian Div, Kirenskii Inst Phys, Krasnoyarsk 660036, Russia
ИФ СО РАН
Kirenskii Institute of Physics, Siberian Division, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk, 660036, Russian Federation

Доп.точки доступа:
Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Гавричков, Владимир Александрович
}
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12.


    Korshunov, M. M.
    The effective Hamiltonian of the singlet-triplet model for copper oxides / M. M. Korshunov, S. G. Ovchinnikov // Phys. Solid State. - 2001. - Vol. 43, Is. 3. - P. 416-419, DOI 10.1134/1.1356113. - Cited References: 15 . - ISSN 1063-7834
РУБ Physics, Condensed Matter
Рубрики:
HIGH-TC SUPERCONDUCTORS
   BAND-STRUCTURE

   LA2-XSRXCUO4

   MECHANISM

   SYMMETRY

   SPECTRUM

Аннотация: The effective Hamiltonian for a realistic multiband p-d model is developed. In the case of electron doping, the Hamiltonian coincides with that for the standard t-J model. For hole doping, the singlet-triplet t-J model takes place. (C) 2001 MAIK "Nauka/Interperiodica".

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Держатели документа:
Krasnoyarsk State Univ, Krasnoyarsk 660062, Russia
Russian Acad Sci, Siberian Div, Kirenskii Inst Phys, Krasnoyarsk 660036, Russia
ИФ СО РАН
Krasnoyarsk State University, Krasnoyarsk, 660062, Russian Federation
Kirenskii Inst. of Physics, Siberian Division, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk, 660036, Russian Federation

Доп.точки доступа:
Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Коршунов, Максим Михайлович
}
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13.


    Ovchinnikov, S. G.
    Spin excitons - A new mechanism of superconducting pairing in copper oxides / S. G. Ovchinnikov // JETP Letters. - 1996. - Vol. 64, Is. 1. - P. 25-31, DOI 10.1134/1.567153. - Cited References: 22 . - ISSN 0021-3640
РУБ Physics, Multidisciplinary
Рубрики:
HIGH-TC SUPERCONDUCTORS
   SINGLET-TRIPLET MODEL

   LA2-XSRXCUO4

   SR2CUO2CL2

   PLANE

Аннотация: The Fermi and Bose quasiparticle spectrum in copper oxides is studied in a many-band p-d model taking account of the strong electronic correlations. It is shown that hole-doped systems possess a Bose mode - a spin exciton - which is associated with the singlet-triplet excitation of the two-hole ground-state term of CuO4 clusters. Intercluster hopping leads to fermion-boson interaction with a spin exciton as the intermediate boson. Such a mechanism does not exist for n-type systems. (C) 1996 American Institute of Physics.

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Держатели документа:
L. V. Kirenskii Institute of Physics, Russian Academy of Sciences, 660036 Krasnoyarsk, Russian Federation
ИФ СО РАН

Доп.точки доступа:
Овчинников, Сергей Геннадьевич
}
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14.


    Shneyder, E. I.
    Isotope effect in the model of strongly correlated electrons with the magnetic and phonon superconducting pairing mechanisms / E. I. Shneyder, S. G. Ovchinnikov // J. Exp. Theor. Phys. - 2009. - Vol. 109, Is. 6. - P. 1017-1021, DOI 10.1134/S1063776109120139. - Cited References: 42. - This study was financed under programs 5.7 and "Quantum Physics of Condensed Matter" of the Presidium of the Russian Academy of Sciences, integration project no. 40 of the Siberian Branch and Ural Division of the Russian Academy of Sciences, and the Russian Foundation for Basic Research (project no. 09-02-00127). . - ISSN 1063-7761
РУБ Physics, Multidisciplinary
Рубрики:
CUPRATE SUPERCONDUCTORS
   PHASE-TRANSITIONS

   3-CENTER INTERACTIONS

   HUBBARD-MODEL

   TEMPERATURE

   LA2-XSRXCUO4

   SYMMETRY

   EXCHANGE

   COPPER

   BI2SR2CACU2O8+DELTA

Кл.слова (ненормированные):
Ab initio calculations -- Calculated values -- Cooper pairing -- Isotope effect -- Magnetic mechanisms -- Order of magnitude -- Pairing mechanism -- Phonon mechanism -- Strongly correlated electrons -- Superconducting pairing mechanism -- Superconducting state -- Type theory -- Carrier mobility -- Electron-phonon interactions -- Isotopes -- Superconductivity -- Superconducting magnets
Аннотация: Peculiarities of the temperature isotope effect in a BCS-type theory describing the exchange and phonon mechanisms of Cooper pairing in a system of strongly correlated electrons are considered. The electron-phonon interaction constant is determined from the fitting of the calculated value of the isotope-effect index to the observed value with the parameters of La(2 - x) Sr (x) CuO(4) obtained from ab initio calculations. The value of this constant indicates that the contribution from the traditional pairing mechanism to the superconducting state is of the same order of magnitude as the contribution from the magnetic mechanism.

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Публикация на русском языке Шнейдер, Елена Игоревна. Изотопический эффект в модели сильно коррелированных электронов, учитывающей магнитный и фононный механизмы сверхпроводящего спаривания [Текст] / Е. И. Шнейдер, С. Г. Овчинников // Журн. эксперим. и теор. физ. - 2009. - Т. 136 Вып. 6. - С. 1177-1182

Держатели документа:
[Shneyder, E. I.
Ovchinnikov, S. G.] Russian Acad Sci, LV Kirensky Phys Inst, Siberian Branch, Krasnoyarsk 660036, Russia
[Shneyder, E. I.] Siberian State Aerosp Univ, Krasnoyarsk 660014, Russia
[Ovchinnikov, S. G.] Siberian Fed Univ, Krasnoyarsk 660041, Russia
ИФ СО РАН
Kirensky Institute of Physics, Siberian Branch, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk, 660036, Russian Federation
Siberian State Aerospace University, Krasnoyarsk, 660014, Russian Federation
Siberian Federal University, Krasnoyarsk, 660041, Russian Federation

Доп.точки доступа:
Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Шнейдер, Елена Игоревна; Presidium of the Russian Academy of Sciences [40]; Russian Academy of Sciences; Russian Foundation for Basic Research [09-02-00127]
}
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15.


    Gavrichkov, V. A.
    Electronic structure and order parameter symmetry in high-temperature superconductors / V. A. Gavrichkov, E. V. Kuz'min, S. G. Ovchinnikov // Uspekhi Fiz. Nauk. - 2000. - Vol. 170, Is. 2. - P. 189-192. - Cited References: 31 . - ISSN 0042-1294
РУБ Physics, Multidisciplinary
Рубрики:
CORRELATED ELECTRONS
   HUBBARD-MODEL

   OXIDES

   LA2-XSRXCUO4


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Держатели документа:
LV Kirenskii Inst Phys, Krasnoyarsk 660036, Russia
Krasnoyarsk State Univ, Krasnoyarsk, Russia
ИФ СО РАН

Доп.точки доступа:
Kuz'min, E. V.; Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Гавричков, Владимир Александрович
}
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16.


    Ovchinnikov, S. G.
    Modification of magnetic and superconducting properties of layered cuprates due to copper substitution for zinc and nickel / S. G. Ovchinnikov // Fiz. Tverd. Tela. - 1995. - Vol. 37, Is. 12. - P. 3645-3654. - Cited References: 28 . - ISSN 0367-3294
РУБ Physics, Condensed Matter
Рубрики:
ELECTRONIC-STRUCTURE
   LA2CUO4

   LA2-XSRXCUO4

   EXCITATIONS

   DENSITY

   PLANE

   NI


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