Труды сотрудников института физики

/ M. M. Korshunov, S. G. Ovchinnikov // Eur. Phys. J. B. - 2007. - Vol. 57, Is. 3. - P. 271-278, DOI 10.1140/epjb/e2007-00179-2. - Cited References: 49 . - ISSN 1434-6028РУБ Physics, Condensed Matter

Аннотация: In this paper a mean-field theory for the spin-liquid paramagnetic non-superconducting phase of the p- and n-type high-T-c cuprates is developed. This theory applied to the effective t-t'-t ''-J* model with the ab initio calculated parameters and with the three-site correlated hoppings. The static spin-spin and kinematic correlation functions beyond Hubbard-I approximation are calculated self-consistently. The evolution of the Fermi surface and band dispersion is obtained for the wide range of doping concentrations x. For p-type systems the three different types of behavior are found and the transitions between these types are accompanied by the changes in the Fermi surface topology. Thus a quantum phase transitions take place at x = 0.15 and at x = 0.23.Due to the different Fermi surface topology we found for n-type cuprates only one quantum critical concentration, x = 0.2. The calculated doping dependence of the nodal Fermi velocity and the effective mass are in good agreement with the experimental data.

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Держатели документа:
Russian Acad Sci, LV Kirensky Phys Inst, Siberian Branch, Krasnoyarsk 660036, Russia
Max Planck Inst Phys Komplexer Syst, D-01187 Dresden, Germany
ИФ СО РАН
L.V. Kirensky Institute of Physics, Siberian Branch, Russian Academy of Sciences, 660036 Krasnoyarsk, Russian Federation
Max-Planck-Institut fur Physik Komplexer Systeme, 01187 Dresden, Germany

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

/ V. V. Val'kov, D. M. Dzebisashvili // J. Exp. Theor. Phys. - 2005. - Vol. 100, Is. 3. - P. 608-616, DOI 10.1134/1.1901772. - Cited References: 29 . - ISSN 1063-7761РУБ Physics, Multidisciplinary

Аннотация: The renormalizations of the fermionic spectrum are considered within the framework of the t-J* model taking into account three-center interactions (H-(3)) and magnetic fluctuations. Self-consistent spin dynamics equations for strongly correlated fermions with three-center interactions were obtained to calculate quasi-spin correlators. A numerical self-consistent solution to a system of ten equations was obtained to show that, in the nearest-neighbor approximation, simultaneously including H-(3) and magnetic fluctuations at n > n(1) (n(1) approximate to 0.72 for 2t/U = 0.25) caused qualitative changes in the structure of the energy spectrum. A new Van Hove singularity is then induced in the density of states, and an additional maximum appears in the T-c(n) concentration dependence of the temperature of the transition to the superconducting phase with order parameter symmetry of the d(x2-y2) type. (C) 2005 Pleiades Publishing, Inc.

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Держатели документа:
Russian Acad Sci, LV Kirensky Phys Inst, Siberian Div, Krasnoyarsk 660036, Russia
Krasnoyarsk State Tech Univ, Krasnoyarsk 660074, Russia
Krasnoyarsk State Univ, Krasnoyarsk 660075, Russia
ИФ СО РАН
Kirenskii Inst. of Physics, Siberian Division, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk, 660036, Russian Federation
Krasnoyarsk State Tech. University, Krasnoyarsk, 660074, Russian Federation
Krasnoyarsk State University, Krasnoyarsk, 660075, Russian Federation

Доп.точки доступа:
Dzebisashvili, D. M.; Дзебисашвили, Дмитрий Михайлович; Вальков, Валерий Владимирович