Библиотека института физики им. Л.В. Киренского СО РАН

Главная

Базы данных

Труды сотрудников ИФ СО РАН - результаты поиска

Вид поиска

Каталог книг и брошюр библиотеки ИФ СО РАН

Каталог журналов библиотеки ИФ СО РАН

Труды сотрудников ИФ СО РАН

Область поиска

в найденном

Найдено в других БД:

Каталог книг и брошюр библиотеки ИФ СО РАН (1)

Формат представления найденных документов:
полный	информационный	краткий

Отсортировать найденные документы по:
автору	заглавию	году издания	типу документа

Поисковый запрос: (<.>K=diagram<.>)

Общее количество найденных документов : 96
Показаны документы с 1 по 20

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volkov N. V., Mikhashenok N. V., Sablina K. A., Bayukov O. A., Gorev M. V., Balaev A. D., Pankrats A. I., Tugarinov V. I., Velikanov D. A., Molokeev M. S., Popkov S. I.
Заглавие : Magnetic phase diagram of the olivine-type Mn2GeO4 single crystal estimated from magnetic, resonance and thermodynamic properties
Место публикации : J. Phys.: Condens. Matter. - 2013. - Vol. 25, No. 13. - Ст.136003. - P. - DOI 10.1088/0953-8984/25/13/136003
Аннотация: Mn2GeO4 single crystals with the olivine structure grown by the modified flux method have been investigated. Pronounced magnetic phase transitions at T1 = 47.7 K, T2 = 17 K and T3 = 5.5 K, with T2 being dependent on an applied magnetic field, have been found. Based on the data of magnetic, resonance and temperature measurements, the entire phase diagram of Mn2GeO4 has been built. Mn2GeO4 is shown to be a material with a complex magnetic structure consisting of two magnetic subsystems.
Смотреть статью,
WOS,
Читать в сети ИФ
Найти похожие

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Каган, Максим Юрьевич, Вальков, Валерий Владимирович, Мицкан, Виталий Александрович, Коровушкин, Максим Михайлович
Заглавие : Механизм Кона-Латтинжера и фазовая диаграмма сверхпроводящего состояния в модели Шубина-Вонсовского
Место публикации : Журн. эксперим. и теор. физ. - 2013. - Т. 144, Вып. 4. - С. 837-852
Аннотация: В рамках модели Шубина - Вонсовского для режима слабой связи WUV (W - ширина зоны, U - хаббардовское отталкивание на узле, V - кулоновское взаимодействие на соседних узлах) на основе механизма Кона - Латтинжера определены области реализации сверхпроводящих фаз с dxy-, p-, s- и dx2-y2-типами симметрии параметра порядка. Показано, что для эффективного взаимодействия в куперовском канале существенную роль играют не только одноузельные, но и межузельные кулоновские корреляции. Этот факт продемонстрирован на примере качественного изменения и усложнения фазовой диаграммы сверхпроводящего состояния. Вскрыт механизм индуцирования сверхпроводящей фазы при учете поляризационных вкладов во втором порядке теории возмущений по кулоновскому взаимодействию. Проведено сравнение полученных результатов по угловой зависимости сверхпроводящей щели в различных каналах с экспериментальными данными по фотоэмиссии с угловым разрешением (ARPES). Проанализировано влияние дальних перескоков на фазовую диаграмму и критическую температуру сверхпроводящего перехода в различных каналах. Определены условия возникновения сверхпроводимости Кона - Латтинжера с dx2-y2-типом симметрии и высокими значениями критической температуры Tc ~ 100 K вблизи половинного заполнения.
Смотреть статью,
Читать в сети ИФ
Найти похожие

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gavriliuk A. G., Lyubutin I. S., Starchikov S. S., Mironovich A. A., Ovchinnikov S. G., Trojan I. A., Xiao, Yuming, Chow P., Sinogeikin S. V., Struzhkin V. V.
Заглавие : The magnetic P-T phase diagram of langasite Ba3TaFe 3Si2O14 at high hydrostatic pressures up to 38 GPa
Место публикации : Applied Physics Letters. - 2013. - Vol. 103, Is. 16. - Ст.162402. - P. - ISSN 0003-6951, DOI 10.1063/1.4822422
Аннотация: The langasite-type crystals with 3d ions are considered as a class of multiferroics in which ferroelectricity can be induced by the magnetic ordering. In this paper, the high-pressure magnetic states of the langasite-type powdered sample Ba3TaFe3Si2O14 have been investigated in a diamond anvil cell by the nuclear forward scattering of synchrotron radiation technique at different temperatures in hydrostatic conditions. In the pressure range of 0 < P < 19.5 GPa, an increase of the Neel temperature TN from 27 to 41 K was observed in the antiferromagnetic phase of the material. At pressures ?19.5 GPa, a transition to another magnetic phase with huge increase in the Neel temperature to ?120 K was found. We attribute this change to the structural transition at ?19.5 GPa which is evidenced by a drastic change of Raman spectra at this pressure. A tentative magnetic P-T phase diagram of Ba3TaFe 3Si2O14 is proposed. В© 2013 AIP Publishing LLC.
Scopus,
Смотреть статью,
WOS,
Читать в сети ИФ
Найти похожие

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Aleksandrova I. P., Ivanov Y. N., Bondarev V. S., Sukhovskii A. A., Voronov V. N.
Заглавие : Calorimetric and 23Na MAS NMR study of the phase diagram of NANB1_xTAxO3 solid solutions
Место публикации : Functional Materials. - 2010. - Vol. 17, Is. 1. - P.18-23. - ISSN 1027-5495
Аннотация: The heat capacity of NaNb1_xTaxO3 solid solutions was measured in the temperature range 100 to 770 K. The step-like change of phase transition temperature is observed in the T-x phase diagram at concentration x = 0.55. The obtained results are in a good agreement with the data of dielectric studies. The 23Na MAS NMR spectra were obtained at Larmor frequency 79.35 MHz using a Bruker AVANCE 300 spectrometer. The quadru-polar coupling constant, (CQ=e2qQ/h) and asymmetry parameter (n) were determined by computer fitting of the NMR line shape using the DMFit software. The found parameters show that solid solution structure is NaTa03-based at 0.7<X ?1 and NaNbO3-based at 0?x?0.5. The spectra in the intermediate region (0.5<x?0.7) can be described at a reasonable accuracy when assuming the coexistence of NaTaO3 and NaNbO3 structures. В© 2010 - STC "Institute for Single Crystals".
Scopus
Найти похожие

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kagan M. Y., Val'kov V. V., Mitskan V. A., Korovushkin M. M.
Заглавие : The Kohn-Luttinger mechanism and phase diagram of the superconducting state in the Shubin-Vonsovsky model
Место публикации : Journal of Experimental and Theoretical Physics. - 2013. - Vol. 117, Is. 4. - P.728-741. - ISSN 1063-7761, DOI 10.1134/S1063776113120030
Аннотация: Using the Shubin-Vonsovsky model in the weak-coupling regime W > U > V (W is the bandwidth, U is the Hubbard onsite repulsion, and V is the Coulomb interaction at neighboring sites) based on the Kohn-Luttinger mechanism, we determined the regions of the existence of the superconducting phases with the d xy, p, s, and $d-{x. - y. } $ symmetry types of the order parameter. It is shown that the effective interaction in the Cooper channel considerably depends not only on single-site but also on intersite Coulomb correlations. This is demonstrated by the example of the qualitative change and complication of the phase diagram of the superconducting state. The superconducting (SC) phase induction mechanism is determined taking into account polarization contributions in the second-order perturbation theory in the Coulomb interaction. The results obtained for the angular dependence of the superconducting gap in different channels are compared with angule-resolved photoemission spectroscopy (ARPES) results. The influence of long-range hops in the phase diagram and critical superconducting transition temperature in different channels is analyzed. The conditions for the appearance of the Kohn-Luttinger superconductivity with the $d-{x. - y. } $ symmetry and high critical temperatures T c ? 100 K near the half-filling are determined. В© 2013 Pleiades Publishing, Inc.
Scopus,
Смотреть статью,
WOS,
Читать в сети ИФ
Найти похожие

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gavriliuk A. G., Struzhkin V. V., Ovchinnikov S. G., Yu Y., Korshunov M. M., Mironovich A. A., Lin J. F., Jin C. Q.
Заглавие : P-T phase diagram of iron arsenide superconductor NdFeAsO0.88F0.12
Место публикации : Europhys. Lett. - 2012. - Vol. 100, Is. 4. - Ст.46005. - ISSN 0295-5075, DOI 10.1209/0295-5075/100/46005
Примечания : Cited References: 26. - This work is supported by DOE (grant No. DE-FG02-02ER45955), by the Russian Foundation for Basic Research (grants 11-02-00291-a, 11-02-00636-a, 12-02-90410_Ukr-a, 12-02-31534-a), by the RAS Program "Strongly correlated electronic systems", by the Russian Ministry of Science (grants 01.164.12.HB11, 16.518.11.7021), Presidium of RAS programs "Quantum physics of condensed matter" project 20.7 and "Matter at high density of energy" project 2.16, FCP Scientific and Research-and-Educational Personnel of Innovative Russia for 2009-2013 (GK 2011-1.3.1-121-018 and GK 16.740.12.0731). Work at UT Austin is supported by Energy Frontier Research in Extreme Environments (EFree) and the Carnegie/DOE Alliance Center (CDAC). SGO and MMK were partially supported by the Leading scientific schools of Russia (NSh 1044-2012.2). MMK acknowledges support from the Dynasty Foundation and ICFPM.
Предметные рубрики: TRANSITION
METAL
Аннотация: NdFeAsO0.88F0.12 belongs to the recently discovered family of high-T-C iron-based superconductors. We have studied the influence of high pressure on transport properties of this material at low temperatures using the four-probe electrical conductivity technique in a diamond cell. Contrary to La-based compounds, we did not observe a maximum in T-C under pressure. Under compression, T-C drops rapidly as a linear function of pressure with the slope k = -2.8 +/- 0.1 K/GPa. Under decompression, the behavior is completely reversible. The extrapolated value of T-C at zero pressure is about T-C(0) = 51.7 +/- 0.4 K. At pressures higher than similar to 18.4 GPa, the superconducting state disappears at all measured temperatures, although electrical resistance changes slope dramatically and shows a concave behavior. These observations may be related to the Kondo effect or to a weak localization of two-dimensional carriers at high pressures and low temperatures below similar to 45 K, indicating a competition mechanism with the superconducting phase. On the bases of our experimental data, we propose a tentative P-T phase diagram of NdFeAsO0.88F0.12. Copyright (C) EPLA, 2012
Смотреть статью,
Scopus,
WoS,
Читать в сети ИФ
Найти похожие

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kartashev A. V., Molokeev M. S., Isaenko L. I., Zhurkov S. A., Fokina V. D., Gorev M. V., Flerov I. N.
Заглавие : Heat capacity and structure of Rb2KMeO3F3 (Me: Mo, W) elpasolites
Коллективы : Siberian Branch of the Russian Academy of Sciences [34]; Russian Federation for the Support of Leading Scientific Schools of the Russian Federation [NSh-4645.2010.2]
Место публикации : Solid State Sci.: ELSEVIER SCIENCE BV, 2012. - Vol. 14, Is. 1. - P.166-170. - ISSN 1293-2558, DOI 10.1016/j.solidstatesciences.2011.11.019
Примечания : Cited References: 12. - This study was supported by the Siberian Branch of the Russian Academy of Sciences (Grant no. 34) and the Council on Grants from the President of the Russian Federation for the Support of Leading Scientific Schools of the Russian Federation (NSh-4645.2010.2).
Предметные рубрики: T PHASE-DIAGRAM
Rb2KMoO3F3
TRANSITION
Ключевые слова (''Своб.индексиров.''): oxyfluorides--crystal structure--phase transition--calorimetry
Аннотация: X-ray and heat capacity measurements were performed on Rb2KMoO3F3 and Rb2KWO3F3 single crystals. A significant difference in the thermal parameters of atoms in 4a and 8c sites of Fm-3m structure was found, which depended on the central atom. Calorimetric measurements have revealed the heat capacity anomalies at 195 and 67 K, respectively, in Rb2KMoO3F3 and Rb2KWO3F3. The standard molar enthalpy and entropy were determined. Entropy changes associated with phase transitions in oxyfluorides under study and related Rb2KTiOF5 are discussed. 2011 Elsevier Masson SAS. All rights reserved.
Смотреть статью,
Scopus,
WoS,
Читать в сети ИФ
Найти похожие

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Val'kova T. A., Val'kov V. V.
Заглавие : Modifying the spin diagram technique for describing quantum magnets with strong fluctuations
Коллективы : International Interdisciplinary Symposium “Ordering in Minerals and Alloys” (14th; 8 -13 Sept. 2011; Rostov-on-Don)
Место публикации : Bull. Russ. Acad. Sci.: Phys.: Allerton Press, 2012. - Vol. 76, Is. 7. - P.768-770. - ISSN 1062-8738, DOI 10.3103/S1062873812070374
Примечания : Cited References: 7. - This work was supported by the Quantum Physics of Condensed Matter Program for Basic Research of the Presidium of the Russian Academy of Sciences; and by the federal target program Scientists and Science Teachers of an Innovative Russia, 2009–2013.
Ключевые слова (''Своб.индексиров.''): elementary excitations--first-order--mass operator--quantum magnets--self-consistent field method--spin operators--magnets--spin fluctuations
Аннотация: Using the diagram technique for spin operators, the exact representations for quantum magnets are obtained that express the Green's functions via the components of mass operator ∑αβ, end factors L and Q, and the Larkin-and Dyson-irreducible part T- irr.The elementary excitation spectrum and mean magnetization are calculated accurate to the first-order contributions on the parameter r0 -3 by the self-consistent field method.
Смотреть статью,
Scopus,
Читать в сети ИФ
Найти похожие

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kagan M. Y., Val'kov V. V., Mitskan V. A., Korovushkin M. M.
Заглавие : The Kohn-Luttinger effect and anomalous pairing in new superconducting systems and graphene
Коллективы : Physics Department of the Russian Academy of Sciences [P.3.1]; Russian Foundation for Basic Research [14-02-00058, 14-02-31237]; Russian Federation [MK-526.2013.2]; Dynasty Foundation
Место публикации : J. Exp. Theor. Phys.: MAIK Nauka-Interperiodica / Springer, 2014. - Vol. 118, Is. 6. - P.995-1011. - ISSN 1063-7761, DOI 10.1134/S1063776114060132. - ISSN 1090-6509
Примечания : Cited References: 114. - This study was supported by the Program of the Physics Department of the Russian Academy of Sciences (project no. P.3.1) and the Russian Foundation for Basic Research (project nos. 14-02-00058 and 14-02-31237). The work of two coauthors (M. M. K. and V.A.M) was supported financially by grant no. MK-526.2013.2 of the President of the Russian Federation and the Dynasty Foundation.
Предметные рубрики: P-WAVE SUPERCONDUCTIVITY
EXTENDED HUBBARD-MODEL
NARROW ENERGY-BANDS
2D KONDO-LATTICE
FERMI GAS
REPULSIVE INTERACTIONS
ELECTRON CORRELATIONS
COOPER INSTABILITY
PHASE-DIAGRAM
SPECTRUM
Аннотация: We present a review of theoretical investigations into the Kohn-Luttinger nonphonon superconductivity mechanism in various 3D and 2D repulsive electron systems described by the Fermi-gas, Hubbard, and Shubin-Vonsovsky models. Phase diagrams of the superconducting state are considered, including regions of anomalous s-, p-, and d-wave pairing. The possibility of a strong increase in the superconducting transition temperature T c even for a low electron density is demonstrated by analyzing the spin-polarized case or the two-band situation. The Kohn-Luttinger theory explains or predicts superconductivity in various materials such as heterostructures and semimetals, superlattices and dichalcogenides, high-T c superconductors and heavy-fermion systems, layered organic superconductors, and ultracold Fermi gases in magnetic traps. This theory also describes the anomalous electron transport and peculiar polaron effects in the normal state of these systems. The theory can be useful for explaining the origin of superconductivity and orbital currents (chiral anomaly) in systems with the Dirac spectrum of electrons, including superfluid 3He-A, doped graphene, and topological superconductors.
Смотреть статью,
Scopus,
WoS,
Читать в сети ИФ
Найти похожие

10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Flerov I. N., Gorev M. V., Aleksandrov K. S., Tressaud A., Fokina V. D.
Заглавие : Ferroelastic phase transitions in fluorides with cryolite and elpasolite structures
Место публикации : Crystallogr. Rep. - 2004. - Vol. 49, Is. 1. - P.100-107. - ISSN 1063-7745, DOI 10.1134/1.1643969
Примечания : Cited References: 43
Предметные рубрики: NUCLEAR MAGNETIC-RESONANCE
THERMODYNAMIC PROPERTIES
RB2KMIIIF6 ELPASOLITES
NEUTRON-DIFFRACTION
CRYSTALS
PEROVSKITES
DIAGRAM
SC
RB2KGAXSC1-XF6
SCATTERING
Аннотация: The ferroelastic phase transitions are investigated in several series of fluoride crystals belonging to the elpasolite and cryolite families (space group Fm (3) over barm) with the general formula A(2)BB'F-6. The influence of the size and shape of cations and anions on the entropy and the mechanism of structural distortions is discussed. (C) 2004 MAIK "Nauka/Interperiodica".
WOS,
Читать в сети ИФ
Найти похожие

11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Pogoreltsev E. I., Flerov I. N., Kartashev A. V., Bogdanov E. V., Laptash N. M.
Заглавие : Heat capacity, entropy, dielectric properties and T–p phase diagram of (NH4)3TiF7
Коллективы : Russian Foundation for Basic Research [15-02-02009]; Council on Grants from the President of the Russian Federation for the Support of Leading Scientific Schools of the Russian Federation [NSh-924.2014.2]
Место публикации : J. Fluor. Chem.: Elsevier Science, 2014. - Vol. 168. - P.247-250. - ISSN 0022-1139, DOI 10.1016/j.jfluchem.2014.10.016. - ISSN 1873-3328
Примечания : Cited References: 16. - This work was supported by the Russian Foundation for Basic Research (Grant no. 15-02-02009), and the Council on Grants from the President of the Russian Federation for the Support of Leading Scientific Schools of the Russian Federation (Grant no. NSh-924.2014.2).
Предметные рубрики: CRYSTAL-STRUCTURE
TRANSITIONS
FLUORIDES
NH4F
Ключевые слова (''Своб.индексиров.''): cubic fluorides--phase transitions--dielectric--phase diagram--calorimetry
Аннотация: Successive phase transitions G1 -- G2 -- G3 in the double salt (NH4)(3)TiF7 have been studied by detailed calorimetric, DTA under hydrostatic pressure and dielectric measurements. Rather large entropy jumps at phase transition points were found to be followed by large additional contributions associated with the temperature dependence of the excess heat capacity. The permittivity behaviour and the tangent of the dielectric losses proved the nonferroelectric nature of both transformations. Two triple-points were found on the temperature-pressure phase diagram, suggesting the existence of a hypothetical parent G0 = Pm-3m cubic phase. A direct transformation between high (G0) and low (G3) temperature cubic phases takes place at p 0.41 GPa with a baric coefficient dT(G0) -- (G3)/dp = -40 K/GPa. (C) 2014 Elsevier B.V. All rights reserved.
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Shaykhutdinov K. A., Nikitin S. E., Petrov M. I., Terent'yev K. Yu., Semenov S. V., Popkov S. I.
Заглавие : Positive magnetoresistance of single-crystal bilayer manganites (La1−zNdz)1.4Sr1.6Mn2O7 (z = 0, 0.1)
Место публикации : J. Appl. Phys.: American Institute of Physics, 2015. - Vol. 117, Is. 16. - Ст.163918. - ISSN 0021, DOI 10.1063/1.4918916. - ISSN 10897550(eISSN)
Примечания : Cited References:24
Предметные рубрики: MAGNETIC PHASE-DIAGRAM
COLOSSAL MAGNETORESISTANCE
LAYERED MANGANITES
Аннотация: We investigate magnetoresistance, rho(c), of single-crystal bilayer lanthanum manganites (La1-zNdz)(1.4)Sr1.6Mn2O7 (z - 0 and 0.1) at a transport current flowing along the crystal c axis and in external magnetic fields applied parallel to the crystal c axis or ab plane. It is demonstrated that the La1.4Sr1.6Mn2O7 manganite exhibits the positive magnetoresistance effect in the magnetic field applied in the ab sample plane at the temperatures T 60 K, along with the negative magnetoresistance typical of all the substituted lanthanum manganites. In the (La0.9Nd0.1)(1.4)Sr1.6Mn2O7 sample, the positive magnetoresistance effect is observed at temperatures of 60-80K in an applied field parallel to the c axis. The mechanism of this effect is shown to be fundamentally different from the colossal magnetoresistance effect typical of lanthanum manganites. The positive magnetoresistance originates from spin-dependent tunneling of carriers between the manganese-oxygen bilayers and can be explained by features of the magnetic structure of the investigated compounds. (C) 2015 AIP Publishing LLC.
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Mel'nikova S. V., Laptash N. M.
Заглавие : Optical studies of the (T-x) phase diagram of oxyfluoride (NH4)2MoO2F4-Rb2MoO2F4 solid solutions
Коллективы : Russian Federation [NSh-924.2014.2]
Место публикации : Phys. Solid State: MAIK Nauka-Interperiodica / Springer, 2015. - Vol. 57, Is. 6. - P.1201-1205. - ISSN 1063, DOI 10.1134/S1063783415060256. - ISSN 10906460(eISSN)
Примечания : Cited References:8. - This study was supported by the Council on Grants from the President of the Russian Federation for Supporting of Leading Scientific Schools of the Russian Federation (grant NSh-924.2014.2).
Предметные рубрики: TRANSITIONS
(NH4)2WO2F4
CRYSTALS
DISORDER
Аннотация: Single crystals of solid solutions (NH4)2 − x Rb x MoO2F4 (including individual complex Rb2MoO2F4) have been grown and studied using polarization-optical methods. The birefringence Δn(T) has been measured in the temperature range of 100–400 K. The complete (T-x) phase diagram has been constructed.
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Flerov I. N., Gorev M. V., Melnikova S. V., Afanasyev M. L., Aleksandrov K. S.
Заглавие : Investigations of ferroelastic phase transitions in ABF6 6H2O crystals (A: Zn, Co, Mg, Mn, Fe; B: Ti, Si)
Место публикации : Ferroelectrics. - 1993. - Vol. 143, Is. 1. - P.11-16. - ISSN 00150193, DOI 10.1080/00150199308008307
Ключевые слова (''Своб.индексиров.''): ferroelastic--phase transition, --birefringence--phase diagram--deuteration
Аннотация: Investigations of twinning, birefringence, heat capacity, effect both of deuteration and of hydrostatic pressure were carried out on crystals of ABF6-6H2O family. The high-temperature and high-pressure phases were found in some compounds. The hypothetic p-T phase diagram was suggested describing the variety of phases observed up to now in this family of crystals.
Смотреть статью
Найти похожие

15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kagan M. Y., Mitskan V. A., Korovushkin M. M.
Заглавие : Phase diagram of the Kohn-Luttinger superconducting state for bilayer graphene
Место публикации : Eur. Phys. J. B: Springer, 2015. - Vol. 88, Is. 6. - Ст.157. - ISSN 1434, DOI 10.1140/epjb/e2015-60198-x. - ISSN 14346036(eISSN)
Примечания : Cited References:60. - The authors are grateful to V.V. Val'kov for valuable remarks. This work is supported by the Russian Foundation for Basic Research (Projects Nos. 14-02-00058 and 14-02-31237). One of the authors (M.Yu.K.) gratefully acknowledges support from the Basic Research Program of the National Research University Higher School of Economics. Another one (M.M.K.) thanks the scholarship SP-1361.2015.1 of the President of the Russian Federation and the Dynasty foundation.
Предметные рубрики: REPULSIVE INTERACTIONS
DOPED GRAPHENE
HUBBARD-MODEL
FERMI-SURFACE
Аннотация: The effect of Coulomb interaction between Dirac fermions on the formation of the Kohn-Luttinger superconducting state in bilayer doped graphene is studied disregarding of the effect of the van der Waals potential of the substrate and impurities. The phase diagram determining the boundaries of superconductive domains with different types of symmetry of the order parameter is built using the extended Hubbard model in the Born weak-coupling approximation with allowance for the intratomic, interatomic, and interlayer Coulomb interactions between electrons. It is shown that the Kohn-Luttinger polarization contributions up to the second order of perturbation theory in the Coulomb interaction inclusively and an account for the long-range intraplane Coulomb interactions significantly affect the competition between the superconducting phases with the f-, p + ip-, and d + id-wave symmetries of the order parameter. It is demonstrated that the account for the interlayer Coulomb interaction enhances the critical temperature of the transition to the superconducting phase.
Смотреть статью,
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kagan M.Yu., Mitskan V. A., Korovushkin M. M.
Заглавие : Effect of the long-range Coulomb interaction on the phase diagram of the Kohn–Luttinger superconducting state in Idealized graphene
Место публикации : J. Low Temp. Phys.: Springer/Plenum Publishers, 2015. - Vol. - P.1-7. - ISSN 0022, DOI 10.1007/s10909-015-1427-2. - ISSN 15737357(eISSN)
Ключевые слова (''Своб.индексиров.''): unconventional superconductivity--kohn-luttinger mechanism--graphene monolayer
Аннотация: The effect of the long-range Coulomb interaction on the formation of the Kohn–Luttinger superconductivity in monolayer doped graphene is studied disregarding the Van der Waals potential of the substrate and both magnetic and non-magnetic impurities. It is shown that the allowance for the Kohn–Luttinger renormalizations up to the second order in perturbation theory in the on-site Hubbard interaction inclusively, as well as in the intersite Coulomb interaction, significantly affects the interplay between the superconducting phases with the f-wave, p+ip-wave, and d+id-wave symmetries of the order parameter. It is demonstrated that taking Coulomb repulsion of electrons located at the next-nearest neighboring atoms in such a system into account changes qualitatively the phase diagram and enhances the critical temperature of the transition to the superconducting phase.
Смотреть статью,
WOS,
Читать в сети ИФ
Найти похожие

17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kagan M. Y., Mitskan V. A., Korovushkin M. M.
Заглавие : High-Tc and Low-Tc superconductivity in electron systems with repulsion
Коллективы : Russian Foundation for Basic Research [14-02-00058, 14-02-31237]; Basic Research Program of the National Research University Higher School of Economics; Dynasty foundation; [SP-1361.2015.1]
Место публикации : J. Supercond. Nov. Magn.: Springer, 2016. - Vol. 29, Is. 4. - P.1043-1048. - ISSN 1557-1939, DOI 10.1007/s10948-016-3384-7. - ISSN 1557-1947(eISSN)
Примечания : Cited References:31. - The authors are grateful to V. V. Val'kov, I. S. Burmistrov, M. V. Feigel'man, and A. Ya. Tzalenchuk for valuable remarks. This work is supported by the Russian Foundation for Basic Research (nos. 14-02-00058 and 14-02-31237). One of the authors (M. Yu. K.) gratefully acknowledges support from the Basic Research Program of the National Research University Higher School of Economics. Another one (M. M. K.) thanks the scholarship SP-1361.2015.1 of the President of Russia and the Dynasty foundation.
Предметные рубрики: Fermion systems
Doped graphene
Hubbard-model
Phase-diagram
Superfluidity
Density
Ключевые слова (''Своб.индексиров.''): unconventional superconductivity--kohn-luttinger mechanism--graphene
Аннотация: We demonstrate the instability of the normal state of purely repulsive fermionic systems towards the transition to the Kohn-Luttinger superconducting state. We construct the superconducting phase diagrams of these systems in the framework of the Hubbard and Shubin-Vonsovsky models on the square and hexagonal lattices. We show that an account for the long-range Coulomb interactions, as well as the Kohn- Luttinger renormalizations, lead to an increase in the critical superconducting temperatures in various materials, such as high-temperature superconductors, idealized monolayer, and bilayer of doped graphene. Additionally, we discuss the role of the structural disorder and the nonmagnetic impurities in superconducting properties of real graphene systems.
Смотреть статью,
WOS,
Читать в сети ИФ
Найти похожие

18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Fokina V. D., Bovina A. F., Bogdanov E. V., Pogorel'tsev E. I., Laptash N. M., Gorev M. V., Flerov I. N.
Заглавие : Specific heat, cell parameters, phase T-p diagram, and permittivity of cryolite (NH4)(3)Nb(O-2)(2)F-4
Разночтения заглавия :авие SCOPUS: Specific heat, cell parameters, phase T-p diagram, and permittivity of cryolite (NH4)3Nb(O2)2F4
Место публикации : Phys. Solid State: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2011. - Vol. 53, Is. 10. - P2147-2153. - ISSN 1063-7834, DOI 10.1134/S1063783411100131
Примечания : Cited References: 19. - This study was performed within the Interdisciplinary integration project of the Siberian Branch of the Russian Academy of Science no. 34 and supported by the grant of the President of the Russian Federation for Leading Scientific Schools of the Russian Federation (NSh-4645.2010.2).
Предметные рубрики: CRYSTAL-STRUCTURES
TRANSITIONS
(NH4)(3)TIOF5
OXYFLUORIDE
COMPLEXES
CAPACITY
DISORDER
Аннотация: The temperature dependences of the specific heat, unit cell parameters, susceptibility to hydrostatic pressure, and permittivity of cryolite (NH4)(3)Nb(O-2)(2)F-4 have been studied. Phase transitions of nonferroelectric nature have been detected. Entropy parameters point to the relation of structure distortions to ordering processes.
WOS,
Scopus,
Читать в сети ИФ
Найти похожие

19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Pankrats A. I., Petrakovskii G. A., Tugarinov V. I., Kartashev A. V., Temerov V. L.
Заглавие : Magnetic-resonance and thermophysical studies of the magnetic phase diagram for a GdFe2.1Ga0.9(BO3)(4) single crystal
Разночтения заглавия :авие SCOPUS: Magnetic-resonance and thermophysical studies of the magnetic phase diagram for a GdFe2.1Ga0.9(BO3)4 single crystal
Место публикации : J. Exp. Theor. Phys.: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2011. - Vol. 113, Is. 3. - P483-489. - ISSN 1063-7761, DOI 10.1134/S1063776111070089
Примечания : Cited References: 21. - This work was supported by the Russian Foundation for Basic Research (project no. 10-02-00765a).
Предметные рубрики: IRON BORATE GDFE3(BO3)(4)
ND3+
Ключевые слова (''Своб.индексиров.''): anisotropy field--antiferromagnetic resonance--critical fields--entire domain--field dependence--iron ions--magnetic phase diagrams--resonance measurement--thermophysical--antiferromagnetism--magnetic fields--magnetic properties--magnetic resonance--metal ions--phase diagrams--single crystals--antiferromagnetic materials
Аннотация: The antiferromagnetic resonance, heat capacity, magnetic properties, and magnetic phase diagram of a GdFe3(BO3)(4) crystal in which some of the iron ions were substituted by diamagnetic gallium ions have been investigated. It has been found that the Ne,l temperature upon diamagnetic substitution decreased to 17 K compared to 38 K in the unsubstituted crystal. The effective exchange and anisotropy fields for GdFe2.1Ga0.9(BO3)(4) have been estimated from the field dependences of magnetization and resonance measurements. The magnetic phase diagram of the crystal has been constructed from magnetic and resonance measurements. In GdFe2.1Ga0.9(BO3)(4), there is no spontaneous reorientation and, in the absence of a magnetic field, the crystal remains an easy-axis one in the entire domain of magnetic ordering. The critical field of the reorientation transition to an induced easy-plane state in a magnetic field along the trigonal axis has been found to increase compared to that in the unsubstituted crystal.
WOS,
Scopus,
Читать в сети ИФ
Найти похожие

20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Pisarev R. V., Kalashnikova A. M., Schops O., Bezmaternykh L. N.
Заглавие : Electronic transitions and genuine crystal-field parameters in copper metaborate CuB2O4
Разночтения заглавия :авие SCOPUS: Electronic transitions and genuine crystal-field parameters in copper metaborate CuB 2O 4
Место публикации : Phys. Rev. B: AMER PHYSICAL SOC, 2011. - Vol. 84, Is. 7. - Ст.75160. - ISSN 1098-0121, DOI 10.1103/PhysRevB.84.075160
Примечания : Cited References: 65. - Useful discussions with W. Weber on crystal-field splitting of 3d states in cuprates are appreciated. We thank H.-J. Weber for the help in using Cary 2300 spectrophotometer. This work is supported by the Russian Foundation for Basic Research (project No. 09-02-00070) and Federal Agency for Science and Innovations (Grant No. 02.740.11.0384). A. M. K. acknowledges the financial support from the Committee for Science and Higher Education of the Government of Saint Petersburg.
Предметные рубрики: OPTICAL-ABSORPTION
PHASE-DIAGRAM
CUGEO3
SPECTRUM
SUPERCONDUCTORS
EXCITATIONS
SR2CUO2CL2
SCATTERING
LA2CUO4
CUPRATE
Аннотация: We present and analyze high-resolution alpha-, sigma-, and pi-polarized absorption spectra related to d-d electronic transitions in tetragonal metaborate CuB2O4 where copper Cu2+ ions occupy two crystallographically distinct 4b and 8d positions. The spectra are characterized by exceptionally rich fine structure in the spectral range of 1.4-2.4 eV. Six zero-phonon (ZP) lines originating from the electronic transitions within the Cu2+ ions in both positions are distinguished and identified. Symmetry analysis explains polarization properties of the ZP lines in the 8d positions but only partially explains them in the 4b positions. Reliable assignment of all six ZP lines to specific transitions allowed us to calculate genuine cubic Dq and tetragonal Ds and Dt crystal-field parameters for both positions. We show that the (3r(2) - z(2)) state, the energy of which is the measure of the Jahn-Teller splitting, is the highest 3d state for both types of Cu2+ ion positions. Using the obtained crystal-field parameters as the reference values, we estimated Dq, Ds, and Dt for several other cuprates with different Cu-O bond lengths. In particular, the 3d level splitting in La2CuO4, Nd2CuO4, CuGeO3, Sr2CuO2Cl2, and Cu3B7O13Cl was analyzed. Our estimates suggest that the Jahn-Teller splitting in some of these cuprates is larger than it was assumed previously.
WOS,
Scopus,
Читать в сети ИФ
Найти похожие