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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kagan M.Yu., Val'kov V. V.
Заглавие : Anomalous resistivity and the electron-polaron effect in the two- band Hubbard model with one narrow band
Место публикации : arXiv. - 2011. - Ст.1111.3135
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kagan M. Yu., Val'kov V. V.
Заглавие : Anomalous Resistivity and the Origin of Heavy Mass in the Two-Band Hubbard Model with One Narrow Band
Место публикации : J. Exp. Theor. Phys. - NEW YORK: PLEIADES PUBLISHING INC, 2011. - Vol. 113, Is. 1. - С. 156-171. - JUL. - ISSN 1063-7761, DOI 10.1134/S1063776111060021. - ISSN 1090-6509
Примечания : Cited Reference Count: 87. - RFBRRussian Foundation for Basic Research (RFBR) [08-02-00224, 08-02-00212]; Leverhulme trustLeverhulme Trust; CNRSCentre National de la Recherche Scientifique (CNRS)European Commission [236694], We are grateful to A. S. Alexandrov, A. F. Andreev, A. F. Barabanov, M. A. Baranov, Yu. Bychkov, A. V. Chubukov, D. V. Efremov, P. Fulde, A. S. Hewson, Yu. Kagan, K. A. Kikoin, K. I. Kugel, F. V. Kusmartsev, M. Mezard, Yu. E. Lozovik, P. Nozieres, N. V. Prokof'ev, A. L. Rakhmanov, T. M. Rice, A. O. Sboychakov, G. V. Shlyapnikov, P. Thalmeyer, C. M. Varma, D. Vollhardt, P. Woelfle, and A. Yaresko for the numerous simulating discussions on this subject and acknowledge financial support of the RFBR grants nos. 08-02-00224, 08-02-00212. M. Yu. K. is also grateful to Loughborough University (UK) and LPTMS (Orsay, France) for the hospitality during the final stage of this work and acknowledges financial support from the Leverhulme trust and CNRS (contract no. 236694).
Предметные рубрики: Physics, Multidisciplinary
Аннотация: We search for marginal Fermi-liquid behavior [1] 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 effect [2] and other mechanisms of mass enhancement (related to 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 the tendency towards phase separation (towards negative partial compressibility of heavy particles) in the 3D case for a large mismatch between the densities of heavy and light bands in the strong-coupling limit. We also observe that for low temperatures and equal densities, the homogeneous state resistivity R(T) similar to T-2 behaves in a Fermi-liquid fashion in both 3D and 2D cases. For temperatures higher than the effective bandwidth for heavy electrons T W-h*, the coherent behavior of the heavy component is totally destroyed. The heavy particles move diffusively in the surrounding of light particles. At the same time, the light particles scatter on the heavy ones as if on immobile (static) impurities. In this regime, the heavy component is marginal, while the light one is not. The resistivity saturates for T W-h* in the 3D case. In 2D, the resistivity has a maximum and a localization tail due to weak-localization corrections of the Altshuler-Aronov type [3]. Such behavior of resistivity could be relevant for some uranium-based heavy-fermion compounds like UNi2Al3 in 3D and for some other mixed-valence compounds possibly including layered manganites in 2D. We also briefly consider the superconductive (SC) instability in the model. The leading instability is towards the p-wave pairing and is governed by the enhanced Kohn-Luttinger [4] mechanism of SC at low electron density. The critical temperature corresponds to the pairing of heavy electrons via polarization of the light ones in 2D.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Aplesnin S. S.
Заглавие : Dimer state in the two-dimensional anisotropic alternated-exchange Heisenberg model
Место публикации : Phys. Solid State: AMER INST PHYSICS, 1998. - Vol. 40, Is. 6. - P986-990. - ISSN 1063-7834, DOI 10.1134/1.1130463
Примечания : Cited References: 14
Предметные рубрики: SPIN-PEIERLS
HUBBARD-MODEL
SUPERCONDUCTIVITY
ANTIFERROMAGNETS
Аннотация: An analysis is made of the two-dimensional Heisenberg model with S = 1/2, anisotropic exchange interaction between nearest neighbors, and alternating exchange in two directions, [100] and [010] (corresponding to condensation of the (pi,pi) mode) and in one direction [100] (corresponding to condensation of the (pi,0) mode), The quantum Monte Carlo method is used to calculate the thermodynamic characteristics and the spin correlation functions which are used as the basis to determine the boundary of stability of an anisotropic antiferromagnetic with respect to alternation of exchange delta = (1 - J(x,y) / J(z))(0.4) in the (pi,pi) model and delta = (1 - J(x,y) / J(z))(0.31) in the (pi,0) model. In the (pi,0) model a disordered quantum state exists in the range (1 - J(x,y) / J(z))(0.31) delta (0.3-0.35). The energy (E - 0.68)
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Lundin U., Sandalov I., Eriksson O., Johansson B.
Заглавие : Are there two types of f-electrons in Pr-metal?
Коллективы : International Conference on Strongly Correlated Electron Systems
Место публикации : Physica B. - 1999. - Vol. 259-61. - P.231-232. - ISSN 0921-4526, DOI 10.1016/S0921-4526(98)00790-X
Примечания : Cited References: 1
Предметные рубрики:
Ключевые слова (''Своб.индексиров.''): band calculations--hubbard model--f-electrons
Аннотация: We show that in order to properly describe the bonding properties of strongly correlated systems, here demonstrated for praseodymium metal, it is necessary to split the f-electron system into two parts. Using perturbation theory from the atomic limit we show that LDA-based calculations with f-electrons in the core can be considered as the limit of an infinite Hubbard U. Then, the correction to the total energy proportional to 1/U makes the upper f(2)--f(3) intra-atomic transitions (IT) important. Mixing interaction and f-f-hopping delocalize these IT and some of them become populated. These IT give an additional contribution to the cohesive energy. This gain in energy is the reason for the separation of the f-electron system into localized (with reduced spectral weight) and delocalized ones. (C) 1999 Elsevier Science B.V. All rights reserved.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kolovsky A. R., Korsch H. J., Graefe E. M.
Заглавие : Bloch oscillations of Bose-Einstein condensates: Quantum counterpart of dynamical instability
Место публикации : Phys. Rev. A. - 2009. - Vol. 80, Is. 2. - ISSN 1050-2947, DOI 10.1103/PhysRevA.80.023617
Примечания : Cited Reference Count: 35. - Гранты: We thank D. Witthaut and F. Trimborn for valuable comments. Support from the Deutsche Forschungsgemeinschaft via the Graduiertenkolleg "Nichtlineare Optik und Ultrakurzzeitphysik" is gratefully acknowledged.Финансирующая организация: Deutsche Forschungsgemeinschaft
Предметные рубрики: OPTICAL LATTICE
ATOMS
Ключевые слова (''Своб.индексиров.''): bloch dynamics--bloch oscillations--bogoliubov--bose-einstein condensates--chaotic dynamics--cold atoms--decoherence--dinger equation--dynamical instabilities--equipartition--hubbard--mean-field--optical lattices--quantum counterpart--quasi-one-dimensional--quasimomentum--bose-einstein condensation--hamiltonians--nonlinear equations--steam condensers--stability
Аннотация: We study the Bloch dynamics of a quasi-one-dimensional Bose-Einstein condensate of cold atoms in a tilted optical lattice modeled by a Hamiltonian of Bose-Hubbard type. The corresponding mean-field system described by a discrete nonlinear Schrodinger equation can exhibit dynamical (or modulation) instability due to chaotic dynamics and equipartition over the quasimomentum modes. It is shown that these phenomena are related to Bogoliubov's depletion of the Bose-Einstein condensate and a decoherence of the condensate in the many-particle description. Three types of dynamics are distinguished: (i) decaying oscillations in the region of dynamical instability and (ii) persisting Bloch oscillations or (iii) periodic decay and revivals in the region of stability.
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Вид документа : Статья из сборника (выпуск продолж. издания)
Шифр издания :
Автор(ы) : Bychek A. A., Muraev P. S., Maksimov D. N., Bulgakov E. N., Kolovsky A. R.
Заглавие : Chaotic and regular dynamics in the three-site Bose-Hubbard model
Коллективы : International Conference on Quantum Technologies
Место публикации : AIP Conf. Proc. - 2020. - Vol. 2241. - Ст.020007. - DOI 10.1063/5.0011540
Примечания : Cited References: 30. - This work has been supported through Russian Science Foundation Grant N19-12-00167
Аннотация: We analyze the energy spectrum of the three-site Bose-Hubbard model. It is shown that this spectrum is a mixture of the regular and irregular spectra associated with the regular and chaotic components of the classical Bose-Hubbard model. We find relative volumes of these components by using the pseudoclassical approach. Substituting these values in the Berry-Robnik distribution for the level spacing statistics we obtain good agreement with the numerical data.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Shneyder E. I., Spitaler J., Kokorina E. E., Nekrasov I. A., Gavrichkov V. A., Draxl C., Ovchinnikov S. G.
Заглавие : Coupling of Hubbard fermions with phonons in La2 CuO4: A combined study using density-functional theory and the generalized tight-binding method
Место публикации : J. Alloys Compd.: Elsevier, 2015. - Vol. 648. - P.258-264. - ISSN 0925-8388, DOI 10.1016/j.jallcom.2015.05.150
Примечания : 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.
Предметные рубрики: MEAN-FIELD THEORY
LINEAR-RESPONSE THEORY
CUPRATE SUPERCONDUCTORS
ELECTRONIC-STRUCTURE
CORRELATED SYSTEMS
LATTICE-DYNAMICS
BAND-STRUCTURE
LA2CUO4
MODEL
LA2-XSRXCUO4
Ключевые слова (''Своб.индексиров.''): 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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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Korshunov M. M., Gavrichkov V. A., Ovchinnikov S. G., Nekrasov I. A., Kokorina E. E., Pchelkina Z. V.
Заглавие : Dominance of many-body effects over the one-electron mechanism for band structure doping dependence in Nd2-xCexCuO4: the LDA + GTB approach
Разночтения заглавия :авие SCOPUS: Dominance of many-body effects over the one-electron mechanism for band structure doping dependence in Nd2-xCexCuO4: The LDA+GTB approach
Место публикации : J. Phys.: Condens. Matter: IOP PUBLISHING LTD, 2007. - Vol. 19, Is. 48. - Ст.486203. - ISSN 0953-8984, DOI 10.1088/0953-8984/19/48/486203
Примечания : Cited References: 36
Предметные рубрики: NARROW ENERGY BANDS
HUBBARD-MODEL
SUPERCONDUCTORS
DENSITY
TEMPERATURE
ORBITALS
WAVE
Ключевые слова (''Своб.индексиров.''): antiferromagnetism--band structure--correlation methods--crystal structure--local density approximation--superconducting materials--electronic correlations--fermionic quasiparticles--neodymium compounds
Аннотация: In the present work we report band structure calculations for the high-temperature superconductor Nd2-xCexCuO4 in the regime of strong electronic correlations within an LDA + GTB method, which combines the local density approximation (LDA) and the generalized tight-binding method (GTB). The two mechanisms of band structure doping dependence were taken into account. Namely, the one-electron mechanism provided by the doping dependence of the crystal structure, and the many-body mechanism provided by the strong renormalization of the fermionic quasiparticles due to the large on-site Coulomb repulsion. We have shown that, in the antiferromagnetic and in the strongly correlated paramagnetic phases of the underdoped cuprates, the main contribution to the doping evolution of the band structure and Fermi surface comes from the many-body mechanism.
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Вид документа : Статья из журнала (Препринт)
Шифр издания :
Автор(ы) : Kuz'min V. I., Visotin M. A., Nikolaev S. V., Ovchinnikov S. G.
Заглавие : Doping and temperature evolution of pseudogap and spin-spin correlations in the two-dimensional Hubbard model [Electronic resource]
Место публикации : ArXiv. - 2020. - Ст.2001.05143
Вид и объем ресурса: Electronic text data
Примечания : Cited References: 86. - The reported study was funded by RFBR according to the research project No. 18-32-00256 (all the results concerning the influence of short-range correlations on the electronic spectral properties). The reported study was also funded by Russian Foundation for Basic Research and Government of Krasnoyarsk Territory, Krasnoyarsk Regional Fund of Science to the research projects “Electronic correlation effects and multiorbital physics in iron-based materials and cuprates” number 19-42-240007, and “Features of electron-phonon coupling in high-temperature superconductors with strong electron correlations” number 18-42-240017
Предметные рубрики: Strongly Correlated Electrons
Аннотация: Cluster perturbation theory is applied to the two-dimensional Hubbard t−t′−t′′−U model to obtain doping and temperature dependent electronic spectral function with 4×4 and 12-site clusters. It is shown that evolution of the pseudogap and electronic dispersion with doping and temperature is similar and in both cases it is significantly influenced by spin-spin short-range correlations. When short-range magnetic order is weakened by doping or temperature and Hubbard-I like electronic dispersion becomes more pronounced, the Fermi arc turns into large Fermi surface and the pseudogap closes. It is demonstrated how static spin correlations impact the overall dispersion's shape and how accounting for dynamic contributions leads to momentum-dependent spectral weight at the Fermi surface and broadening effects.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kuz'min V. I., Visotin M. A., Nikolaev S. V., Ovchinnikov S. G.
Заглавие : Doping and temperature evolution of pseudogap and spin-spin correlations in the two-dimensional Hubbard model
Коллективы : RFBRRussian Foundation for Basic Research (RFBR) [18-32-00256, 18-32-01062]; Russian Foundation for Basic ResearchRussian Foundation for Basic Research (RFBR); Government of Krasnoyarsk Territory; Krasnoyarsk Regional Fund of Science [19-42-240007, 18-42-240017]
Место публикации : Phys. Rev. B. - 2020. - Vol. 101, Is. 11. - Ст.115141. - ISSN 2469-9950, DOI 10.1103/PhysRevB.101.115141. - ISSN 2469-9969(eISSN)
Примечания : Cited References: 97. - The reported study was funded by RFBR according to Research Project No. 18-32-00256 (all the results concerning the influence of short-range correlations on the electronic spectral properties). The reported study was also funded by RFBR according to Research Project No. 18-32-01062; the Russian Foundation for Basic Research and Government of Krasnoyarsk Territory, the Krasnoyarsk Regional Fund of Science to the Research Projects "Electronic correlation effects and multiorbital physics in iron-based materials and cuprates" No. 19-42-240007 and "Features of electron-phonon coupling in high-temperature superconductors with strong electron correlations" No. 18-42-240017.
Предметные рубрики: QUASI-PARTICLE DISPERSION
FERMI-SURFACE
QUANTUM OSCILLATIONS
LANCZOS METHOD
Аннотация: Cluster perturbation theory is applied to the two-dimensional Hubbard t - t' - t '' - U model to obtain doping and temperature-dependent electronic spectral function with 4 x 4 and 12-site clusters. It is shown that evolution of the pseudogap and electronic dispersion with doping and temperature is similar and in both cases it is significantly influenced by spin-spin short-range correlations. When short-range magnetic order is weakened by doping or temperature and Hubbard-I-like electronic dispersion becomes more pronounced, the Fermi arc turns into a large Fermi surface and the pseudogap closes. It is demonstrated how static spin correlations impact the overall dispersion's shape and how accounting for dynamic contributions leads to momentum-dependent spectral weight at the Fermi surface and broadening effects.
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