Труды сотрудников института физики

/ S. V. Stolyar [et al.] // J. Sib. Fed. Univ. Math. Phys. - 2013. - Vol. 6, Is. 3. - P. 358-365 ; Журн. СФУ. Сер. "Математика и физика" . - ISSN 1997-1397
   Перевод заглавия: Структура и магнитные свойства биогенных наночастиц ферригидрита, легированных гадолинием
Аннотация: Bacterial culture Klebsiella oxytoca was grown in a Lovley medium at various concentrations of gadolinium salt. Biogenic magnetic nanoparticles of ferrihydrite were investigated by Mossbauer spectroscopy and magnetization curves were obtained. The results of structural studies showed that iron Fe(5) takes new position when cultivating is carried out in medium with high concentrations of gadolinium. It was found that gadolinium is fit into the crystal structure of ferrihydrite. These results are consistent with the analysis of the magnetization curves.

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Доп.точки доступа:
Stolyar, S. V.; Столяр, Сергей Викторович; Bayukov, O. A.; Баюков, Олег Артемьевич; Ladygina, V. P.; Ischenko, L. A.; Iskhakov, R. S.; Исхаков, Рауф Садыкович

/ А. Chubukov [et al.] // Bull. Amer. Phys. Soc. - 2012. - Vol. 57, № 1. - P. 316
Аннотация: We present a detailed study of the symmetry and structure of the pairing gap in Fe-based superconductors. We treat them as quasi-2D systems, decompose the pairing interaction into s− wave and d− wave channels and into contributions from scattering between different Fermi surfaces and analyze how each scattering evolves with doping and input parameters. We verify that each interaction is well approximated by the lowest angular harmonics and use this simplification to analyze the interplay between the interaction with and without spin-fluctuation components, the origin of the attraction in the s± and d x 2 −y 2 channels, the competition between them, the nature of angular dependence of the s± gaps along the electron Fermi surface, the conditions under which s± gap develops nodes, and the origin of superconductivity in heavily electron- or hole-doped systems, when only Fermi surfaces of one type are present. In particular, we find that with increased electron and hole doping, the competition from d− wave grows. In the case of strong hole doping, there is some ambiguity over the leading solution, but in the case of strong electron doping, d− wave emerges as clear winner.

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Аннотация

Держатели документа:
Институт физики им. Л.В. Киренского СО РАН

Доп.точки доступа:
Chubukov, A. V.; Maiti, S.; Korshunov, M. A.; Коршунов, Михаил Анатольевич; Maier, T.; Hirschfeld, P.J.; APS March Meeting (2012 ; 27 Feb.-2 March ; Boston, Massachusetts, USA); American Physical Society March Meeting (2012 ; 27 Feb.-2 March ; Boston, Massachusetts, USA)

/ M. M. Korshunov // International conferences «Phase separation and Superstripes in High Temperature Superconductors and Related Materials (Superstripes-2012)». - 2012. - P. 39
Аннотация: We introduce an effective low-energy pairing model for Fe-based superconductors with s- and d-wave interaction components and a small number of input parameters and use it to study the doping evolution of the symmetry and the structure of the superconducting gap. We argue that the model describes the entire variety of pairing states found so far in the Fe-based superconductors and allows one to understand the mechanism of the attraction in s(±) and d(x(2)-y(2)) channels, the competition between s- and d-wave solutions, and the origin of superconductivity in heavily doped systems, when only electron or only hole pockets are present.

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Доп.точки доступа:
Коршунов, Максим Михайлович; Ettore Majorana Foundation, Centre for Scientific CultureRome International Center for Materials Science; International School of Solid State Physics; "Phase separation and Superstripes in High Temperature Superconductors and Related Materials", Int. Conf. (55 ; 2012 ; July ; 11-17 ; Erice (Sicily), Italy)

/ 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 1063-7761РУБ Physics, Multidisciplinary

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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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

/ 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 1063-7761РУБ Physics, Multidisciplinary

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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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

/ V. V. Val'kov, M. M. Korovushkin // Bull. Russ. Acad. Sci. Phys. - 2012. - Vol. 76, Is. 2. - P. 133-135, DOI 10.3103/S1062873812020074. - Cited References: 6. - This study was supported by Quantum Physics of Condensed Matter program of the Presidium of the Russian Academy of Sciences; the Russian Foundation for Basic Research, project np. 10-02-00251; the federal target program Scientists and Science Teachers of an Innovate Russia, 2009-2013; the Siberian Branch of the Russian Academy of Sciences, complex integration project no. 53; RF Presidential Grant MK-1300.2011.2; and the Siberian Branch of the Russian Academy of Sciences' Lavrent'ev Competition for Young Scientists. . - ISSN 1062-8738
Аннотация: The effect of the strong intersite Coulomb correlations on the formation of an electron structure in the Shubin-Vonsowsky model in the regime of strong one-site correlations is studied. The results reveal a split-off band of the Fermi states. The spectral intensity of this band grows with the enhancement of the doping level and is determined by the mean-square fluctuation of occupation numbers. This changes the structure of the electron density of states qualitatively. © 2012 Allerton Press, Inc.

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Доп.точки доступа:
Korovushkin, M. M.; Коровушкин, Максим Михайлович; Вальков, Валерий Владимирович; International Symposium "Nanophysics and Nanoelectronics-2011" (March 2011 ; Nizhni Novgorod)

/ A. V. Kuklin [et al.] // J. Alloys Compd. - 2014. - Vol. 609. - P. 93-99, DOI 10.1016/j.jallcom.2014.04.160. - Cited References: 38 . - ISSN 0925-8388. - ISSN 1873-4669РУБ Chemistry, Physical + Materials Science, Multidisciplinary + Metallurgy & Metallurgical Engineering

Аннотация: A detailed study of Ni-doped Mg(0 0 0 1) surface performed by PAW method and the gradient corrected density functional GGA-PBE within the framework of generalized Kohn–Sham density functional theory (DFT) is presented in this work. Structural and electronic properties of magnesium surface interaction with nickel for the purpose of such compounds use for creation of hydrogen storage matrixes were investigated here. Choice of the PBE functional was caused by the good accordance of its prediction of the cell parameters with experimental results. It was shown that Ni atoms prefer to substitute for Mg atoms. Using NEB method, the diffusion barrier was calculated, and the most probable reaction path was established. In particular, when the Ni atom dopes the magnesium surface, it can migrate to the bulk and substitute for Mg in subsurface layers. Also a possibility of nickel cluster formation on clean surface of magnesium was examined. The kinetic factors hinder the movement of the nickel atoms to each other and make problematic the formation of clusters. The studies presented here showed that the diffusion barriers of the nickel atom migration from the cluster on the surface to the bulk of magnesium are 1.179 eV and 1.211 eV for the forward and reverse reactions, respectively. Therefore an improvement of the hydrogenation properties of Ni-doped magnesium surface depends on deposition not of the individual atoms, but their clusters. Hydrogenation of Ni cluster doping the magnesium surface was investigated. Initially Kubas complexes arise on the Ni cluster with hydrogen–hydrogen bond lengths equal to 0.80–0.87 Å. Next the cluster needs to be saturated by hydrogen atoms to allow them later to migrate from cluster to magnesium.

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Держатели документа:
Siberian Fed Univ, Krasnoyarsk 660041, Russia
Kirensky Inst Phys SB RAS, Krasnoyarsk 660036, Russia
Siberian State Technol Univ, Krasnoyarsk 660049, Russia

Доп.точки доступа:
Kuklin, A. V.; Куклин, Артем Валентинович; Kuzubov, A. A.; Кузубов, Александр Александрович; Krasnov, P. O.; Краснов, Павел Олегович; Lykhin, A. O.; Tikhonova, L. V.

[Текст] / L. V. Udod [et al.] // Moscow Int. Symp. on Magnet. (MISM-2014) : Book of abstracts. - 2014. - Ст. 1PO-J1-6. - P. 513 . - ISBN 978-5-91978-025-0

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Доп.точки доступа:
Udod, L. V.; Удод, Любовь Викторовна; Aplesnin, S. S.; Аплеснин, Сергей Степанович; Eremin, E. V.; Еремин, Евгений Владимирович; Sitnikov, M. N.; Molokeev, M. S.; Молокеев, Максим Сергеевич; Moscow International Symposium on Magnetism(6 ; 2014 ; June-July ; Moscow)

/ L. V. Udod [et al.] // Solid State Phenom. : Selected, peer reviewed papers. - 2015. - Vol. 233-234: Achievements in Magnetism. - P. 105-108, DOI 10.4028/www.scientific.net/SSP.233-234.105 . - ISSN 1662-9779. - ISSN 978-3-038
Аннотация: The Bi2(Sn0.95Mn0.05)2O7 compound existing simultaneously in two polymorphic modifications, namely, orthorhombic and cubic has been synthesized for the first time by solid-phase synthesis. The magnetic, dielectric and electrical properties of the compound have been studied. Anomalies in the temperature dependences of the electrical resistance and magnetic propoties have been found. These features are explained as martensitic phase transitions.

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Perov, N. \ed.\; Semisalova, A. \ed.\; Udod, L. V.; Удод, Любовь Викторовна; Aplesnin, S. S.; Аплеснин, Сергей Степанович; Sitnikov, M. N.; Eremin, E. V.; Еремин, Евгений Владимирович; Molokeev, M. S.; Молокеев, Максим Сергеевич; Moscow International Symposium on Magnetism(6 ; 2014 ; June-July ; Moscow)

/ S. G. Ovchinnikov [и др.] // V International symposium on strong nonlinear vibronic and electronic interactions in solids : program, book of abstracts . - 2015. - Ст. O18. - P. 28. - Библиогр.: 1 назв.
   Перевод заглавия: Зависящие от допирования зонная структура и спаривание в системах с сильными электронными корреляциями ВТСП купратов

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Доп.точки доступа:
Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Shneyder, E. I.; Шнейдер, Елена Игоревна; Korshunov, M. M.; Коршунов, Максим Михайлович; Makarov, I. A.; Макаров, Илья Анатольевич; International symposium on strong nonlinear vibronic and electronic interactions in solids(5 ; 2015 ; May ; 1-3 ; Tartu)

/ А. А. Кузубов [и др.] // Вестник СибГАУ. - 2015. - Т. 16, № 3. - С. 743-749. - Библиогр.: 56. - Исследование выполнено при финансовой поддержке РФФИ в рамках научных проектов No 14-02-31071, 14-02-31309. Авторы выражают благодарность информационно-вычислительному центру (ИВЦ) Новосибирского государственного университета (Новосибирск), Институту компьютерного моделирования СО РАН (Красноярск), Межведомственному суперкомпьютерному центру РАН (Москва), компьютерному центру СФУ, а также НИВЦ МГУ «Лаборатории параллельных информационных технологий» (система СКИФ МГУ «Ломоносов») за предоставление возможности использования вычислительных кластеров, на которых были проведены все расчеты. . - ISSN 1816-9724
   Перевод заглавия: Theoretical study of Si (100) doping influence on lithium sorption and diffusion
Аннотация: В настоящее время перспективным анодным материалом нового поколения считается кремний, поскольку он имеет самую высокую теоретическую удельную емкость (4200 мАч/г). Однако одной из проблем, препятствующих широкому использованию данного материала, является медленная диффузия лития с поверхности кремния в объем, которая может быть решена с помощью модификации поверхности кремния. Проведено моделирование поверхностных процессов сорбции и диффузии лития в допированной поверхности Si (100) с помощью метода функционала плотности. В ходе исследования допирования Si (100) одиночными атомами B, Ga, Ge выявлено, что для всех выбранных нами допантов наиболее выгодны положения замещения кремния, а не адсорбции. Энергия связи допанта с пластиной кремния ослабевает в ряду от германия к галлию. Найдено, что атом бора замещает атом третьего слоя кремния, а германий и галлий занимают положение в первом слое. Тенденция первоначальной сорбции атомов лития в канале между димерами по сравнению с чистым материалом сохраняется и при допировании одиночными атомами B, Ga, Ge. Наблюдается значительное снижение (в случае бора) и увеличение (для галия и германия) энергетических барьеров перехода атома лития по поверхности кремниевой пластины. Величины энергетических барьеров перехода L-U с поверхности в приповерхностные слои при допировании возрастают на 0,05 эВ, что свидетельствует о замедлении данной стадии. В результате работы было обнаружено, что допирование бором, галлием и германием (концентрация составляет 0,3 атомных %) поверхности Si (100) не оказывает значительного влияния на сорбционные и диффузионные параметры.
Currently, silicon is the most promising anode material for a new generation of lithium-ion batteries due to its very high theoretical specific capacity (4200 mAh/g). However, one of the problems hindering the wider use of this material is the slow diffusion of lithium from silicon surface into volume that can be solved by modifying silicon surface. The simulation of surface processes of sorption and diffusion of lithium in doped Si (100) was carried out by using the density functional method. In the study Si (100) doped with single atoms B, Ga, Ge, found that the silicon replacement compared to adsorption are more profitable for all dopants. The binding energy of dopant to silicon decreases from germanium to gallium. It was found that boron atom substitutes for the third layer of silicon, germanium and gallium occupy positions in the first layer. In comparison with the pure material the trend of initial lithium sorption in the channel between silicon dimmers retain for Si (100) doped with single atoms of B, Ga, Ge. Energy barriers of lithium transition on silicon surface substantially reduce (in the case of boron) and increase (in the case of gallium and germanium). The energy barrier of transition from surface to surface layers L-U during the doping increases by 0.05 eV, this shows a moderation of the stage. According to the study, Si (100) doping with boron, gallium and germanium (concentration of 0.3 atomic %) has not significant influence on sorption and diffusion parameters.

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Держатели документа:
Институт физики им. Л.В. Киренского СО РАН

Доп.точки доступа:
Кузубов, Александр Александрович; Kuzubov, A. A.; Михалева, Н. С.; Mikhaleva, N. S.; Попов, Захар Иванович; Popov, Z. I.; Краснов, Павел Олегович; Krasnov, P. O.; Николаева, К. М.; Nikolaeva, K. M.

/ S. . Maiti [et al.] // Phys. Rev. B. - 2011. - Vol. 84, Is. 22. - Ст. 224505, DOI 10.1103/PhysRevB.84.224505. - Cited References: 46. - We acknowledge helpful discussions with L. Benfatto, R. Fernandes, W. Hanke, I. Eremin, H. Kontani, K. Kuroki, Y. Matsuda, I. Mazin, R. Prozorov, D. Scalapino, J. Schmalian, Z. Tesanovic, R. Thomale, M. Vavilov, and A. Vorontsov. This work was supported by NSF-DMR-0906953 (S. M. and A. V. C.). Partial support from MPI PKS (Dresden) (S. M. and A. V. C.) and the Humboldt Foundation (A. V. C.) is gratefully acknowledged. T. A. M. acknowledges support from the Center of Nanophase Materials Sciences, which is sponsored at Oak Ridge National Laboratory by the Office of Basic Energy Sciences, US Department of Energy. M. M. K. and P. J. H. acknowledge support from DOE DE-FG02-05ER46236. M. M. K. is grateful for support from RFBR (Grant No. 09-02-00127), Presidium of RAS program N5.7, FCP Scientific and Research-and-Educational Personnel of Innovative Russia for 2009-2013 (GK P891 and GK 16.740.12.0731), and the President of Russia (Grant No. MK-1683.2010.2). . - ISSN 1098-0121РУБ Physics, Condensed Matter

Аннотация: We present a detailed study of the symmetry and structure of the pairing gap in Fe-based superconductors (FeSCs). We treat FeSCs as quasi-2D, decompose the pairing interaction in the XY plane in s-wave and d-wave channels into contributions from scattering between different Fermi surfaces, and analyze how each scattering evolves with doping and input parameters. We verify that each interaction is well approximated by the lowest angular harmonics. We use this simplification to analyze the interplay between the interaction with and without spin-fluctuation components, the origin of the attraction in the s(+/-) and d(x2-y2) channels, the competition between them, the angular dependence of the s(+/-) gaps along the electron Fermi surface, the conditions under which the s(+/-) gap develops nodes, and the origin of superconductivity in heavily electron-or hole-doped systems, when only Fermi surfaces of one type are present. We also discuss the relation between RPA and RG approaches for FeSCs.

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Держатели документа:
[Maiti, S.
Chubukov, A. V.] Univ Wisconsin, Dept Phys, Madison, WI 53706 USA
[Korshunov, M. M.
Hirschfeld, P. J.] Univ Florida, Dept Phys, Gainesville, FL 32611 USA
[Korshunov, M. M.] Russian Acad Sci, Siberian Branch, LV Kirensky Phys Inst, Krasnoyarsk 660036, Russia
[Korshunov, M. M.] Siberian Fed Univ, Krasnoyarsk 660041, Russia
[Maier, T. A.] Oak Ridge Natl Lab, Comp Sci & Math Div, Oak Ridge, TN 37831 USA
[Maier, T. A.] Oak Ridge Natl Lab, Ctr Nanophase Mat Sci, Oak Ridge, TN 37831 USA
ИФ СО РАН
Department of Physics, University of Wisconsin, Madison, WI 53706, United States
Department of Physics, University of Florida, Gainesville, FL 32611, United States
L. V. Kirensky Institute of Physics, Siberian Branch, Russian Academy of Sciences, 660036 Krasnoyarsk, Russian Federation
Siberian Federal University, Svobodny Prospect 79, 660041 Krasnoyarsk, Russian Federation
Computer Science and Mathematics Division, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States

Доп.точки доступа:
Maiti, S.; Korshunov, M. M.; Коршунов, Максим Михайлович; Maier, T. A.; Hirschfeld, P. J.; Chubukov, A. V.

/ S. . Maiti [et al.] // Phys. Rev. Lett. - 2011. - Vol. 107, Is. 14. - Ст. 147002, DOI 10.1103/PhysRevLett.107.147002. - Cited References: 29. - We acknowledge helpful discussions with L. Benfatto, A. Bernevig, R. Fernandes, W. Hanke, I. Eremin, Y. Matsuda, I. Mazin, R. Prozorov, D. Scalapino, Z. Tesanovic, R. Thomale, M. Vavilov, and A. Vorontsov. This work was supported by NSF-DMR-0906953 (S. M. and A. V. C.), DOE DE-FG02-05ER46236 (P. J. H.), the Center for Nanophase Materials Sciences, sponsored at ORNL by the Office of Basic Energy Sciences, DOE (T. A. M.), and RFBR 09-02-00127, Presidium of RAS program N5.7, FCP GK P891, and President of Russia MK-1683.2010.2 (M. M. K.). We are grateful to KITP at Santa Barbara for its hospitality during the work on this manuscript. . - ISSN 0031-9007РУБ Physics, Multidisciplinary

Аннотация: We introduce an effective low-energy pairing model for Fe-based superconductors with s- and d-wave interaction components and a small number of input parameters and use it to study the doping evolution of the symmetry and the structure of the superconducting gap. We argue that the model describes the entire variety of pairing states found so far in the Fe-based superconductors and allows one to understand the mechanism of the attraction in s(+/-) and d(x2-y2) channels, the competition between s- and d-wave solutions, and the origin of superconductivity in heavily doped systems, when only electron or only hole pockets are present.

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Держатели документа:
[Maiti, S.
Chubukov, A. V.] Univ Wisconsin, Dept Phys, Madison, WI 53706 USA
[Korshunov, M. M.
Hirschfeld, P. J.] Univ Florida, Dept Phys, Gainesville, FL 32611 USA
[Korshunov, M. M.] Russian Acad Sci, Siberian Branch, LV Kirensky Phys Inst, Krasnoyarsk 660036, Russia
[Maier, T. A.] Oak Ridge Natl Lab, Comp Sci & Math Div, Oak Ridge, TN 37831 USA
[Maier, T. A.] Oak Ridge Natl Lab, Ctr Nanophase Mat Sci, Oak Ridge, TN 37831 USA
ИФ СО РАН
Department of Physics, University of Wisconsin, Madison, WI 53706, United States
Department of Physics, University of Florida, Gainesville, FL 32611, United States
L.V. Kirensky Institute of Physics, Siberian Branch, Russian Academy of Sciences, 660036 Krasnoyarsk, Russian Federation
Computer Science and Mathematics Division, Center for Nanophase Materials Sciences, Oak Ridge National Lab, Oak Ridge, TN 37831, United States

Доп.точки доступа:
Maiti, S.; Korshunov, M. M.; Коршунов, Максим Михайлович; Maier, T. A.; Hirschfeld, P. J.; Chubukov, A. V.

/ S. G. Ovchinnikov, S. V. Nikolaev // JETP Letters. - 2011. - Vol. 93, Is. 9. - P. 517-520, DOI 10.1134/S0021364011090116. - Cited References: 27. - This work was supported by the Presidium of the Russian Academy of Sciences (program no. 18.7); the Russian Foundation for Basic Research (project nos. 09-02-00127, 10-02-90725-mob_st); Siberian Branch, Russian Academy of Sciences (Integration Project no. N40); and the Ministry of Education and Sciences of the Russian Federation (state contract no. P891, Program "Kadry"). . - ISSN 0021-3640РУБ Physics, Multidisciplinary

Аннотация: The results of recently developed norm-conserving cluster perturbation theory for doping dependent electronic structure of the Hubbard model are reported. We have found that the momentum distribution of the spectral weight strongly depends on the broadening value delta. At delta = 0.1t, we reproduce the angle-resolved photoemission spectroscopy data, while at delta = 0.01t we obtain two quantum phase transitions. DOI: 10.1134/S0021364011090116

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Держатели документа:
[Ovchinnikov, S. G.] Russian Acad Sci, LV Kirensky Phys Inst, Siberian Branch, Krasnoyarsk 660036, Russia
[Ovchinnikov, S. G.] Siberian Fed Univ, Krasnoyarsk 660041, Russia
[Nikolaev, S. V.] Omsk State Univ, Omsk 644077, Russia
ИФ СО РАН
Kirensky Institute of Physics, Siberian Branch, Russian Academy of Sciences, Krasnoyarsk 660036, Russian Federation
Siberian Federal University, Krasnoyarsk 660041, Russian Federation
Omsk State University, Omsk 644077, Russian Federation

Доп.точки доступа:
Nikolaev, S. V.; Овчинников, Сергей Геннадьевич

/ S. G. Ovchinnikov, E. I. Shneyder, M. M. Korshunov // J. Phys.: Condens. Matter. - 2011. - Vol. 23, Is. 4. - Ст. 45701, DOI 10.1088/0953-8984/23/4/045701. - Cited References: 58. - We would like to thank S Sakai for useful discussions. The authors acknowledge support by the Russian Foundation for Basic Research (grant N 09-02-00127), by the Integration Program of SBRAS N40, the Presidium RAS Program 5.7, President of Russia (grant MK-1683.2010.2), FCP Scientific and Research-and-Educational Personnel of Innovative Russia for 2009-2013 (GK P891), and in part by the National Science Foundation under grant NSF PHY05-51164. . - ISSN 0953-8984РУБ Physics, Condensed Matter

Аннотация: Several experimental and theoretical studies indicate the existence of a critical point separating the underdoped and overdoped regions of the high-T-c cuprates' phase diagram. There are at least two distinct proposals on the critical concentration and its physical origin. The first one is associated with the pseudogap formation for p < p*, with p* approximate to 0.2. The other relies on the Hall effect measurements and suggests that the critical point and the quantum phase transition (QPT) take place at optimal doping, p(opt) approximate to 0.16. Here we have performed a precise density of states calculation and found that there are two QPTs and the corresponding critical concentrations associated with the change of the Fermi surface topology upon doping.

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Держатели документа:
[Ovchinnikov, S. G.
Shneyder, E. I.
Korshunov, M. M.] 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
[Korshunov, M. M.] Univ Florida, Dept Phys, Gainesville, FL 32611 USA
ИФ СО РАН
L V Kirensky Institute of Physics, Siberian Branch, Russian Academy of Sciences, 660036 Krasnoyarsk, Russian Federation
Siberian Federal University, Krasnoyarsk 660041, Russian Federation
Reshetnev Siberian State Aerospace University, Krasnoyarsk 660014, Russian Federation
Department of Physics, University of Florida, Gainesville, FL 32611, United States

Доп.точки доступа:
Shneyder, E. I.; Шнейдер, Елена Игоревна; Korshunov, M. M.; Коршунов, Максим Михайлович; Овчинников, Сергей Геннадьевич

/ S. G. Ovchinnikov, I. A. Makarov, E. I. Shneyder // J. Exp. Theor. Phys. - 2011. - Vol. 112, Is. 2. - P. 288-302, DOI 10.1134/S106377611005119X. - Cited References: 64. - This study was supported financially by the program "Quantum Physics of Condensed Media" of the Presidium of the Russian Academy of Sciences (project no. 5.7), the integration projects of the Siberian Branch and the Ural Division of the Russian Academy of Sciences (project no. 40), the Russian Foundation for Basic Research (project no. 09-02-00127), the President of the Russian Federation (grant no. MK-1683.2010.2), and the Federal Target Program P891. . - ISSN 1063-7761РУБ Physics, Multidisciplinary

Аннотация: We present a theoretical study of the electronic structure of bilayer HTSC cuprates and its evolution under doping and in a high magnetic field. Analysis is based on the t-t'-taEuro(3)-J* model in the generalized Hartree-Fock approximation. Possibility of tunneling between CuO2 layers is taken into account in the form of a nonzero integral of hopping between the orbitals of adjacent planes and is included in the scheme of the cluster form of perturbation theory. The main effect of the coupling between two CuO2 layers in a unit cell is the bilayer splitting manifested in the presence of antibonding and bonding bands formed by a combination of identical bands of the layers themselves. A change in the doping level induces reconstruction of the band structure and the Fermi surface, which gives rise to a number of quantum phase transitions. A high external magnetic field leads to a fundamentally different form of electronic structure. Quantum phase transitions in the field are observed not only under doping, but also upon a variation of the field magnitude. Because of tunneling between the layers, quantum transitions are also split; as a result, a more complex sequence of the Lifshitz transitions than in single-layer structures is observed.

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

Доп.точки доступа:
Makarov, I. A.; Макаров, Илья Анатольевич; Shneyder, E. I.; Шнейдер, Елена Игоревна; Овчинников, Сергей Геннадьевич

/ V. V. Val'kov, M. M. Korovushkin // J. Exp. Theor. Phys. - 2011. - Vol. 112, Is. 1. - P. 108-120, DOI 10.1134/S1063776110061056. - Cited References: 26. - We express our deep gratitude to R. O. Zaitsev for numerous remarks and discussions. We are grateful to A. A. Golovnya, A. A. Shklyaev, and V. A. Mitskan for specific advice on the numerical calculations of the mass operator. This work was supported by the "Quantum Condensed Matter Physics" Program of the Presidium of the Russian Academy of Sciences, the Russian Foundation for Basic Research (project no. 10-02-00251), the "Scientific and Scientific-Pedagogical Personnel of Innovational Russian for 2009-2013" Federal Goal-Oriented Program, and the Interdisciplinary Integration Project no. 53 of the Siberian Branch of the Russian Academy of Sciences. One of us (M. K.) thanks Lavrentiev's contest of youth projects of the Siberian Branch of the Russian Academy of Sciences. . - ISSN 1063-7761РУБ Physics, Multidisciplinary

Аннотация: The diagram technique for Hubbard operators is used to investigate the influence of intersite Coulomb interactions on the energy structure and Cooper instability of strongly correlated fermions. Allowance for intersite correlations in doped Mott-Hubbard insulators is shown to lead to a splitting of the lower subband of Hubbard fermions and to the formation of a band of fluctuation states as soon as the intersite interaction energy becomes comparable to or exceeds the mean kinetic energy. The spectral intensity of the splitoff band is proportional to the root-mean-square fluctuation of the occupation numbers and increases with doping level. The predicted effect changes significantly the structure of the density of electronic states. This leads to a renormalization of the pole of the scattering amplitude in the Cooper channel and manifests itself as a nonuniform (in electron concentration) modification of the dependence of the critical superconducting transition temperature.

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Держатели документа:
[Val'kov, V. V.
Korovushkin, M. M.] Russian Acad Sci, LV Kirensky Phys Inst, Siberian Branch, Krasnoyarsk 660036, Russia
[Val'kov, V. V.] Reshetnev Siberian State Aerosp Univ, Krasnoyarsk 660014, Russia
ИФ СО РАН
Kirensky Institute of Physics, Russian Academy of Sciences, Siberian Branch, Krasnoyarsk 660036, Russian Federation
Reshetnev Siberian State Aerospace University, Krasnoyarsk 660014, Russian Federation

Доп.точки доступа:
Korovushkin, M. M.; Коровушкин, Максим Михайлович; Вальков, Валерий Владимирович

/ S. G. Ovchinnikov [et al.] // J. Exp. Theor. Phys. - 2010. - Vol. 111, Is. 1. - P. 104-113, DOI 10.1134/S1063776110070101. - Cited References: 48. - This study was financially supported by the Russian Foundation for Basic Research (project nos. 09-02-01224 and 09-02-00127) and under the program "Quantum Physics of Condensed Media" of the Presidium of the Russian Academy of Sciences (project no. 5.7). . - ISSN 1063-7761РУБ Physics, Multidisciplinary

Аннотация: We report on the results of measurements of anisotropic resistivity of RBa(2)Cu(3)O(6 + x) (R = Tm, Lu) high-temperature superconducting single crystals in a wide range of doping levels, indicating a nontrivial effect of magnetic order on the electronic properties of cuprates. In particular, our results visually demonstrate the crossover from the state with moderate anisotropy of resistivity rho (c) /rho (ab) similar to 30 to a strongly anisotropic state with rho (c) /rho (ab) similar to 7 x 10(3) upon cooling as well as upon a decrease in the hole concentration in the CuO(2) planes. It is also shown that anisotropy is sensitive to the magnetic state of CuO(2) planes and attains its maximum value after the establishment of the long-range antiferromagnetic order. The results are discussed in the framework of the theory based on the t-t'-taEuro(3)-J model of CuO(2) layers taking into account strong electron correlations and short-range magnetic order. In this theory, anomalies of spin correlators and Fermi surface topology for a critical hole concentration of p* a parts per thousand 0.24 are demonstrated. The concentration dependence of the charge carrier energy indicates partial suppression of energy due to the emergence of a pseudogap at p < p*. This theory explains both the experimentally observed sensitivity of anisotropy in conductivity to the establishment of the antiferromagnetic order and the absence of anomalies in the temperature dependence of resistivity rho (ab) (T) in the vicinity of the N,el temperature.

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Держатели документа:
[Ovchinnikov, S. G.
Korshunov, M. M.] Russian Acad Sci, Kirenskii Inst Phys, Siberian Branch, Krasnoyarsk 660036, Russia
[Ovchinnikov, S. G.] Siberian Fed Univ, Krasnoyarsk 660041, Russia
[Korshunov, M. M.] Univ Florida, Dept Phys, Gainesville, FL 32611 USA
[Kozeeva, L. P.
Lavrov, A. N.] Russian Acad Sci, Nikolaev Inst Inorgan Chem, Siberian Branch, Novosibirsk 630090, Russia
ИФ СО РАН
Kirenskii Institute of Physics, Siberian Branch, Russian Academy of Sciences, Krasnoyarsk 660036, Russian Federation
Siberian Federal University, Krasnoyarsk 660041, Russian Federation
Department of Physics, University of Florida, Gainesville, FL 32611, United States
Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090, Russian Federation

Доп.точки доступа:
Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Korshunov, M. M.; Коршунов, Максим Михайлович; Kozeeva, L. P.; Lavrov, A. N.; Лавров, Александр Николаевич

/ 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 0953-8984РУБ Physics, Condensed Matter

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

/ M. M. Korshunov, I. . Eremin // Europhys. Lett. - 2008. - Vol. 83, Is. 6. - Ст. 67003, DOI 10.1209/0295-5075/83/67003. - Cited References: 18. - We would like to thank B. BUCHNER, S.-L. DRECHSLER, D. EFREMOV, P. FULDE, I. MAZIN, R. MOESSNER and D. PARKER for useful discussions. IE acknowledges support from Volkswagen Foundation. . - ISSN 0295-5075РУБ Physics, Multidisciplinary

Аннотация: Employing the four-band tight-binding model, we study theoretically the doping dependence of the spin response in the normal state of novel Fe-based pnictide superconductors. We show that the commensurate spin density wave (SDW) transition that arises due to interband scattering between the hole alpha-pockets and the electron beta-pockets disappears already at the doping concentration x approximate to 0.04 reflecting the evolution of the Fermi surfaces. Correspondingly, with further increase of the doping the antiferromagnetic fluctuations are suppressed for x 0.1 and the imaginary part of the spin susceptibility at antiferromagnetic wave vector becomes nearly temperature independent. At the same time, we observe that the uniform susceptibility deviates from the Pauli-like behavior and is increasing with increasing temperature reflecting the activation processes for the alpha-Fermi surfaces up to temperatures of about T = 800 K. With increase of the doping the absolute value of the uniform susceptibility lowers and its temperature dependence changes. In particular, it is a constant at low temperatures and then decreases with increasing temperature. We discuss our results in a context of recent experimental data. Copyright (C) EPLA, 2008

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Держатели документа:
[Korshunov, M. M.
Eremin, I.] Max Planck Inst Phys Komplexer Syst, D-01187 Dresden, Germany
[Korshunov, M. M.] Russian Acad Sci, Siberian Branch, LV Kirensky Phys Inst, Krasnoyarsk 660036, Russia
[Eremin, I.] Tech Univ Carolo Wilhelmina Braunschweig, Inst Math & Theoret Phys, D-38106 Braunschweig, Germany
ИФ СО РАН
Max-Planck-Institut fur Physik Komplexer Systeme, 01187 Dresden, EU, Germany
L.V. Kirensky Institute of Physics, Siberian Branch, Russian Academy of Sciences, 660036 Krasnoyarsk, Russian Federation
Institute fur Mathematische und Theoretische Physik, TU-Braunschweig, 38106 Braunschweig, EU, Germany
Kazan State University, 420008 Kazan, Russian Federation

Доп.точки доступа:
Eremin, I.; Коршунов, Максим Михайлович