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1.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kagan M. Y., Mitskan V. A., Korovushkin M. M.
Заглавие : Anomalous superconductivity and superfluidity in repulsive fermion systems
Место публикации : Phys. Usp.: Turpion, 2015. - Vol. 58, Is. 8. - P.733-761. - ISSN 10637869 (ISSN), DOI 10.3367/UFNe.0185.201508a.0785
Примечания : Cited References: 369. - We are grateful to M A Baranov, A V Chubukov, D V Efremov, M V Feigel'man, V V Kabanov, K I Kugel', M S Marienko, N M Plakida, N V Prokorev, A Ya Tzalenchuk, and V V Val'kov for the fruitful discussions and constant attention to our work. The work was supported by the Russian Foundation for Basic Research (project nos. 14-02-00058 and 14-02-31237). M Yu K thanks the Program of Basic Research of the National Research University Higher School of Economics for support. The work of MM K was supported by grant of the President of the Russian Federation (SP-1361.2015.1) and the Dinasty Foundation
Предметные рубрики: HEXAGONAL BORON-NITRIDE
SCANNING-TUNNELING-MICROSCOPY
2-DIMENSIONAL HUBBARD-MODEL
HIGH-TC SUPERCONDUCTIVITY
ELECTRON-ENERGY SPECTRUM
P-WAVE SUPERCONDUCTIVITY
DOUBLE-LAYER GRAPHENE
2D KONDO-LATTICE
GROUND-STATE
TRANSITION-TEMPERATURE
Ключевые слова (''Своб.индексиров.''): anomalous superconductivity--kohn-luttinger mechanism--superfluidity--repulsive fermi gas--hubbard and t-jmodel--shubin vonsovsky model--graphene monolayer--graphene bilayer
Аннотация: We discuss the mechanisms of unconventional superconductivity and superfluidity in 3D and 2D fermionic systems with purely repulsive interaction at low densities. We construct phase diagrams of these systems and find the areas of the superconducting state in free space, as well as on the lattice in the framework of the Fermi-gas model with hard-core repulsion, the Hubbard model, the Shubin-Vonsovsky model, and the t-J model. We demonstrate that the critical superconducting temperature can be greatly increased in the spin-polarized case or in a two-band situation already at low densities. The proposed theory is based on the Kohn-Luttinger mechanism or its generalizations and explains or predicts anomalous p-, d-, and f-wave pairing in various materials, such as high-temperature superconductors, the idealized monolayer and bilayer of doped graphene, heavy-fermion systems, layered organic superconductors, superfluid 3He, spin-polarized 3He mixtures in 4He, ultracold quantum gases in magnetic traps, and optical lattices.
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2.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Val'kov V. V., Zlotnikov A. O.
Заглавие : Coexistence of superconductivity and antiferromagnetism in heavy-fermion intermetallic compound CeRhIn5
Место публикации : J. Supercond. Nov. Magn. - 2013. - Vol. 26, Is. 9. - P.2885-2886. - ISSN 1557-1939, DOI 10.1007/s10948-013-2222-4
Ключевые слова (''Своб.индексиров.''): coexistence superconductivity antiferromagnetism--heavy-fermion systems--periodic anderson model
Аннотация: An interference of heavy-fermion superconductivity (SC) and antiferromagnetism (AFM) has been studied in the framework of the periodic Anderson model with the superexchange interaction between localized electrons. It has been shown that pressure-induced energy change of the localized states leads to modifying antiferromagnetic and superconducting order parameters. Conditions have been found for the coexistence of SC and AFM in the model. Theoretical results of the pressure effects on the ground state character of the heavy-fermion systems are in good agreement with experimental data for a rare-earth intermetallic compound CeRhIn5. The divergence of the effective electron mass produced by suppressing the long-range antiferromagnetic order has also been analyzed in the same framework. В© 2013 Springer Science+Business Media New York.
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3.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Val'kov V. V., Zlotnikov A. O.
Заглавие : Coexistence of superconductivity and antiferromagnetism in heavy-fermion intermetallides
Место публикации : Theor. math. phys. - 2013. - Vol. 174, Is. 3. - P.421-437. - DOI 10.1007/s11232-013-0035-z
Аннотация: Using the two-time retarded Green’s function, we study the conditions for realizing the phase of the superconductivity and antiferromagnetism coexistence in the framework of the effective Hamiltonian for the periodic Anderson model. Such a phase was experimentally observed in rare-earth intermetallides with heavy fermions under an external pressure. In the chosen model, the Cooper instability is induced in the presence of long-range antiferromagnetic ordering as a result of the combined effect of a superexchange interaction in the subsystem of localized electrons and the hybridization between two groups of electrons. Applying an external pressure induces an increase in the energy of the localized level accompanied by an abrupt destruction of the long-range antiferromagnetic ordering in a certain region of the phase diagram. The superconductivity order parameter has a maximum value at the destruction point. We show that the decrease in the antiferromagnetic-sublattice magnetization with increasing pressure leads to a significant increase in the masses of Fermi quasiparticles, and the sign of the current carriers reverses at the critical point. The obtained results qualitatively agree well with the experimental data for the heavy-fermion intermetallide CeRhIn 5 .
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4.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kuz'min V. I., Nikolaev S. V., Ovchinnikov S. G.
Заглавие : Comparison of the electronic structure of the Hubbard and t - J models within the cluster perturbation theory
Коллективы : RFBR [13-02-01395-a, 14-02-31677-mol-a, 14-02-00186-a]; Ministry of Education and Science of Russia [3085, SibFU 2014 GF-2]; [NSh-2886.2014.2]
Место публикации : Phys. Rev. B: American Physical Society, 2014. - Vol. 90, Is. 24. - Ст.245104. - ISSN 1098-0121, DOI 10.1103/PhysRevB.90.245104. - ISSN 1550-235X
Примечания : Cited References: 37. - This work is supported by RFBR (Grants No. 13-02-01395-a, No. 14-02-31677-mol-a, and No. 14-02-00186-a), the Ministry of Education and Science of Russia (Government Contract No. 3085, SibFU 2014 GF-2), and a grant of the Russian President (Grant No. NSh-2886.2014.2).
Предметные рубрики: FERMION SYSTEMS
SUPERCONDUCTIVITY
METAL
Аннотация: Electronic dispersion and density of states (DOS) have been calculated for the Hubbard model and the t−J and t−J∗ models with three-site correlated hopping by the cluster perturbation theory. We have found a rather strong quantitative difference both in dispersion and DOS at all doping for the Hubbard and t−J models at the energy scale ω≳t. The three-site correlated hopping addition results in an almost negligible difference for the Hubbard and t−J∗ models. Close to the Fermi energy, at the scale ω≲J, the electronic structure of all three models is similar. We have found the line of zeros of the Green function for the t−J model that has been previously obtained for the Hubbard model by cellular dynamical mean-field theory calculations.
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5.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Val'kov V. V., Dzebisashvili D. M., Barabanov A. F.
Заглавие : d-Wave pairing in an ensemble of spin polaron quasiparticles in the spin-fermion model of the electronic structure of the CuO2 plane
Коллективы : Dynasty Foundation, Russian Foundation for Basic Research (Siberia) [13-02-00523,13-02-00909, 13-02-98013]
Место публикации : Phys. Lett. A: Elsevier Science, 2015. - Vol. 379, Is. 5. - P.421-426. - ISSN 0375, DOI 10.1016/j.physleta.2014.11.036. - ISSN 18732429(eISSN)
Примечания : Cited References:26. - This study was supported by the Russian Foundation for Basic Research,projects Nos. 13-02-00523, 13-02-00909 and 13-02-98013 (Siberia) and theDynasty Foundation.
Предметные рубрики: SUPERCONDUCTIVITY
ANTIFERROMAGNETISM
Ключевые слова (''Своб.индексиров.''): hight-temperature cuprate superconductors--tree-band p-d model--spin--polaron--strong electron correlations
Аннотация: It is demonstrated for the first time that the strong coupling between spin moments of copper ions and oxygen holes, which arises upon hybridization mixing of two hole subsystems in the Emery model, not only affects the formation of spin polaron quasiparticles but also ensures effective attraction between them via the exchange interaction. This results in the Cooper instability with d-wave pairing in a 2D ensemble of spin polaron quasiparticles. The T-x phase diagram obtained using this approach agrees well with the available experimental data. (C) 2014 Elsevier B.V. All rights reserved.
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6.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Вальков, Валерий Владимирович, Дзебисашвили, Дмитрий Михайлович, Барабанов А. Ф.
Заглавие : d-Волновое спаривание спин-поляронных квазичастиц в спин-фермионной модели электронного строения CuO2-плосксти
Коллективы : Южный федеральный университет, "Порядок, беспорядок и свойства оксидов", международный междисциплинарный симпозиум (17; 2014 ; 5-10 сент.; Ростов-на-Дону/ Южный, Ростовская обл.)
Место публикации : XVII межд. симп. "Порядок, беспорядок и св-ва оксидов" (ODPO-17)/ чл. межд. прогр. ком. В. В. Вальков. - 2014. - Вып. 17, Т. 1. - С. 399-403
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7.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Val'kov V. V., Dzebisashvili D. M.
Заглавие : Dynamicalmagnetic susceptibility in the spin-fermion model for cuprate superconductors
Коллективы : Russian Foundation for Basic Research [16-02-00073]; Krasnoyarsk Kray Foundation for Scientific and Technical Progress [16-42-240435]; Siberian Branch of the Russian Academy of Sciences [II.2P, 0356-2015-0405]; Administration of Krasnoyarsk Kray
Место публикации : Theor. Math. Phys. - 2017. - Vol. 193, Is. 3. - P.1853-1864. - ISSN 0040-5779, DOI 10.1134/S004057791712011X. - ISSN 1573-9333(eISSN)
Примечания : Cited References:35. - This research was supported by the Russian Foundation for Basic Research (Grant No. 16-02-00073), the Administration of Krasnoyarsk Kray and the Krasnoyarsk Kray Foundation for Scientific and Technical Progress (Grant No. 16-42-240435), and the complex program No. II.2P of the Siberian Branch of the Russian Academy of Sciences (Grant No. 0356-2015-0405).
Предметные рубрики: T-J MODEL
LONG-RANGE-ORDER
POLARON
CUO2
EXCITATIONS
LATTICE
WAVE
Ключевые слова (''Своб.индексиров.''): high-temperature conductor--spin-fermion model--magnetic susceptibility--spin polaron
Аннотация: Using the method of diagram techniques for the spin and Fermi operators in the framework of the SU(2)-invariant spin-fermion model of the electron structure of the CuO2plane of copper oxides, we obtain an exact representation of the Matsubara Green’s function D⊥(k, iω m ) of the subsystem of localized spins. This representation includes the Larkin mass operator ΣL(k, iω m ) and the strength and polarization operators P(k, iω m ) and Π(k, iω m ). The calculation in the one-loop approximation of the mass and strength operators for the Heisenberg spin system in the quantum spin-liquid state allows writing the Green’s function D⊥(k, iω m ) explicitly and establishing a relation to the result of Shimahara and Takada. An essential point in the developed approach is taking the spin-polaron nature of the Fermi quasiparticles in the spin-fermion model into account in finding the contribution of oxygen holes to the spin response in terms of the polarization operator Π(k, iω m ).
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8.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Val'kov V. V., Zlotnikov A. O.
Заглавие : Effect of pressure on antiferromagnetic and superconducting ordering in systems with heavy fermions
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.733-736. - ISSN 0022-2860, DOI 10.3103/S1062873812070362
Примечания : Cited References: 7. - This work was supported by the Department of Physical Sciences, Russian Academy of Sciences (the Strong Electron Correlations Program); the Russian Foundation for Basic Research, projects nos. 100200251 and 110200741; the RFBR Sibir’, project no. 110298007; and by the federal target program Scientific and Pedagogical Personnel of an Innovative Russia, 2009–2013.
Ключевые слова (''Своб.индексиров.''): antiferromagnetic orderings--antiferromagnetic orders--antiferromagnetic phasis--antiferromagnetics--cooper instability--effect of pressure--external pressures--heavy fermion--impurity level--localized state--periodic anderson model--seed energy--spin moments--superconducting ordering--superexchange interaction--superconductivity--antiferromagnetism
Аннотация: Characteristics of the superconducting and antiferromagnetic phases of heavy-fermion intermet-allides are described within a periodic Anderson model with allowance for the superexchange interaction between spin moments of the localized states. It is shown that an external pressure that changes the seed energy of an impurity level can rapidly destroy the long-range antiferromagnetic order. The development of the Cooper instability near such an order-disorder transition induces the experimentally observed state in which superconductivity coexists with the antiferromagnetic ordering. В© 2012 Allerton Press, Inc.
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9.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Val'kov V. V., Fedoseev A. D.
Заглавие : Effect of total reflection from a symmetric two-channel device with fermion path nonanalyticity points induced by Rashba spin-orbit coupling
Место публикации : Bull. Russ. Acad. Sci. Phys. - 2018. - Vol. 82, Is. 5. - P.550-553. - ISSN 10628738 (ISSN), DOI 10.3103/S1062873818050313
Примечания : Cited References: 8. - The reported study was funded by Russian Foundation for Basic Research (project nos. 16-42-242036, 16-42-243056, and 17-42-240441), Government of Krasnoyarsk Territory, and Krasnoyarsk Region Science and Technology Support Fund to the research (project nos. 22/17, 24/17, and 02/17).
Ключевые слова (''Своб.индексиров.''): electron transport--nonanalyticity--rashba spin-orbit coupling--regular polygon--spin-orbit couplings--symmetric systems--total reflection--transmission coefficients
Аннотация: The effect Rashba spin-orbit coupling has on transmission coefficient through a symmetric system with fermion path nonanalyticity points is illustrated using the example of a regular polygon-shaped chain. It is shown that the current passage through a device is blocked at the critical spin-orbit coupling values determined by the system’s geometry. At the near-critical spin-orbit coupling values, electron transport is possible only in a narrow range of energies.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Val'kov V. V., Dzebisashvili D. M.
Заглавие : EFFECTIVE INTERACTIONS IN THE PERIODIC ANDERSON MODEL IN THE REGIME OF MIXED VALENCY WITH STRONG CORRELATIONS
Коллективы :
Разночтения заглавия :авие SCOPUS: Effective interactions in the periodic Anderson model in the regime of mixed valency with strong correlations
Место публикации : Theor. Math. Phys.: SPRINGER, 2008. - Vol. 157, Is. 2. - P1565-1576. - ISSN 0040-5779, DOI 10.1007/s11232-008-0130-8
Примечания : Cited References: 19. - This work was supported in part by the Russian Foundation for Basic Research (Grant No. 07-02-00226), a program of the Branch of Physical Sciences, Russian Academy of Sciences, and the "Integration Project" of the Siberian Branch, Russian Academy of Sciences.
Предметные рубрики: LATTICE
Ключевые слова (''Своб.индексиров.''): periodic anderson model--mixed valency--heavy fermion--effective hamiltonian--superconductivity--effective hamiltonian--heavy fermion--mixed valency--periodic anderson model--superconductivity
Аннотация: For the periodic Anderson model in the strong correlation regime, we construct the effective Hamiltonian H(eff) up to terms of the fourth order in the parameter V/U, where V is the hybridization interaction intensity and U is the intra-atom Coulomb repulsion strength. This Hamiltonian contains interactions inducing both magnetic ordering and Cooper instability under conditions of a mixed valency of rare-earth ions. Based on numerical calculations, we obtain information about the dependences of the effective interaction parameters on the distance between crystal lattice sites. We demonstrate that realizing exchange interactions corresponds to a strongly frustrated system of localized spin moments and facilitates the suppression of the antiferromagnetic order parameter with a possible transition to the state of a quantum spin liquid. It is essential that among the terms in H(eff) inducing the transition to the superconductivity phase, there are terms resulting in the d-type symmetry of the superconductivity order parameter; such a symmetry is realized in many heavy-fermion compounds.
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Val'kov V. V., Dzebisashvili D. M.
Заглавие : Electron spectrum and heat capacity of heavy fermions in the canted phase of antiferromagnetic intermetallides
Коллективы :
Место публикации : J. Exp. Theor. Phys. - 2010. - Vol. 110, Is. 2. - P.301-318. - ISSN 1063-7761, DOI 10.1134/S1063776110020147
Примечания : Cited References: 41. - This study was supported by the program "Quantum Physics of Condensed Media" of the Presidium of the Russian Academy of Sciences, interdisciplinary integration project no. 53 of the Siberian Branch of the Russian Academy of Sciences, and the Russian Foundation for Basic Research (project no. 07-02-00226).
Предметные рубрики: PERIODIC ANDERSON MODEL
PRESSURE-INDUCED SUPERCONDUCTIVITY
KONDO-LATTICE
FERROMAGNETISM
FLUCTUATIONS
COEXISTENCE
CERHIN5
SYSTEMS
DIAGRAM
CENISN
Ключевые слова (''Своб.индексиров.''): antiferromagnetic phase--antiferromagnetics--antiferromagnets--electron spectrum--electronic heat capacity--energy spectra--experimental data--external magnetic field--heat capacities--heavy fermion--low temperatures--magnetic sublattices--magnetic subsystems--sommerfeld constant--structural rearrangement--temperature dependence--antiferromagnetism--cerium--cerium compounds--fermions--magnetic fields--phase transitions--specific heat--spectroscopy--antiferromagnetic materials
Аннотация: The energy spectrum of heavy fermions in an external magnetic field is calculated for canted magnetic sublattices of antiferromagnetic intermetallides. This makes it possible to determine low-temperature features of electronic heat capacity of heavy-fermion antiferromagnets with the metal-type ground state taking into account the structural rearrangement of the magnetic subsystem. The calculated temperature dependences of the magnetization, heat capacity, and Sommerfeld constant in the vicinity of the point of transition to the antiferromagnetic phase correlate with experimental data obtained for heavy-fermion antiferromagnets PuGa3, Ce2Au2Cd, YbNiSi3, and PuPd5Al2.
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Val'kov V. V., Fedoseev A. D.
Заглавие : Fano antiresonance induced by the rashba spin-orbit coupling in systems with conduction channels exhibiting the points of nonanalyticity in fermion paths
Коллективы : Russian Foundation for Basic Research [16-42-242036, 16-42-243056, 17-42-240441]; Government of the Krasnoyarsk Territory; Krasnoyarsk Region Science and Technology Support Fund [21/16, 29/16, 02/17]
Место публикации : JETP Letters. - 2017. - Vol. 106, Is. 5. - P.302-307. - ISSN 0021-3640, DOI 10.1134/S0021364017170131. - ISSN 1090-6487(eISSN)
Примечания : Cited References:17. - This work was funded by the Russian Foundation for Basic Research (project nos. 16-42-242036, 16-42-243056, and 17-42-240441), Government of the Krasnoyarsk Territory, Krasnoyarsk Region Science and Technology Support Fund to the Research (project nos. 21/16, 29/16, and 02/17).
Аннотация: It is shown that the combined effect of the nonanalyticity of the channel for the motion of charge carriers and the Rashba spin-orbit coupling induces resonant anomalies in the transport characteristics of nanosystems related to the size quantization. When the characteristic length determined by the ratio of the hopping integral and the spin-orbit coupling constant coincides with the distance between the points of nonanalyticity, the size effect arises in the channel. It manifests itself in the complete reflection from the device, which can be treated as the Fano antiresonance. The current-voltage characteristics of the nanosystem with the nonanalytical channel undergo significant changes at slight variations of the spin-orbit coupling constant near its critical value.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gamov, Alexander, Zlotnikov A. O.
Заглавие : Fermion parity of phases supporting multiple Majorana modes in a superconducting nanowire
Колич.характеристики :10 с
Место публикации : J. Sib. Fed. Univ. Math. Phys. - 2023. - Vol. 16, Is. 6. - P.820-829. - ISSN 19971397 (ISSN); Журн. СФУ. Матем. и физ. - ISSN 23136022 (eISSN)
Примечания : Cited References: 22. - Gamov A. acknowledges the support of the Theoretical Physics and Mathematics Advancement Foundation "BASIS"
Аннотация: The fermion parity of the ground state is determined in various topological phases of the semiconducting nanowire under external magnetic field with proximity-induced superconductivity and strong spin-orbit interaction. Electron hopping as well as spin-flip hopping due to spin-orbit coupling and superconducting pairings in the second coordination sphere are taken into account. The connection between the fermion parity and the parity of the BDI topological invariant is shown. The formation of topological phases with three and four pairs of Majorana modes has been demonstrated.Для полупроводниковой нанопроволоки, помещенной во внешнее магнитное поле, с наведенной сверхпроводимостью и сильным спин-орбитальным взаимодействием определена фермионная четность основного состояния в различных топологических фазах при учете перескоков электронов, включая перескоки с переворотом спина за счет спин-орбитальной связи, и сверхпроводящих спариваний во второй координационной сфере. Показана связь фермионной четности и четности BDI топологического инварианта. Продемонстрировано формирование топологических фаз с тремя и четырьмя парами майорановских мод.
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ovchinnikov S. G., Shneyder E. I., Korshunov M. M.
Заглавие : From underdoped to overdoped cuprates: two quantum phase transitions
Разночтения заглавия :авие SCOPUS: From underdoped to overdoped cuprates: Two quantum phase transitions
Место публикации : J. Phys.: Condens. Matter: IOP PUBLISHING LTD, 2011. - Vol. 23, Is. 4. - Ст.45701. - ISSN 0953-8984, DOI 10.1088/0953-8984/23/4/045701
Примечания : 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.
Предметные рубрики: HIGH-TEMPERATURE SUPERCONDUCTORS
T-J MODEL
CORRELATED FERMION SYSTEMS
VALENCE BOND STATE
MEAN-FIELD-THEORY
CRITICAL-POINT
HEISENBERG-ANTIFERROMAGNET
EXCITATIONS
PSEUDOGAP
OSCILLATIONS
Ключевые слова (''Своб.индексиров.''): critical concentration--critical points--cuprates--density of state--fermi surface topology--hall effect measurement--high-t--optimal doping--overdoped--pseudo-gap--quantum phase transitions--theoretical study--copper compounds--hall effect--magnetic field effects--phase diagrams--phase transitions
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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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Valkov V. V., Dzebisashvili D. M., Barabanov A. F.
Заглавие : Generalized Kondo lattice model and its spin-polaron realization by the projection method for cuprates
Коллективы : Russian Foundation for Basic Research [16-02-00073, 16-02-00304, 16-42-240435]; Siberian Branch of the Russian Academy of Sciences (Complex Program) [II.2P, 0358-2015-0005]
Место публикации : Theor. Math. Phys.: MAIK Nauka-Interperiodica / Springer, 2017. - Vol. 191, Is. 2. - P.752-763. - ISSN 0040-5779, DOI 10.1134/S0040577917050142. - ISSN 1573-9333(eISSN)
Примечания : Cited References:35. - This research was supported by the Russian Foundation for Basic Research (Grant No. 16-02-00073, 16-02-00304, and 16-42-240435) and the Siberian Branch of the Russian Academy of Sciences (Complex Program No. II.2P, Grant No. 0358-2015-0005).
Предметные рубрики: HIGH-TEMPERATURE SUPERCONDUCTIVITY
HIGH-TC SUPERCONDUCTORS
COPPER OXIDES
Ключевые слова (''Своб.индексиров.''): strong electron correlation--spin-fermion model--kondo lattice model--spin polaron
Аннотация: The spin-fermion model, which is an effective low-energy realization of the three-band Emery model after passing to the Wannier representation for the px and py orbitals of the subsystem of oxygen ions, reduces to the generalized Kondo lattice model. A specific feature of this model is the existence of spin-correlated hoppings of the current carriers between distant cells. Numerical calculations of the spectrum of spin-electron excitations highlight the important role of the long-range spin-correlated hoppings.
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Val'kov V. V., Mitskan V. A., Shustin M. S.
Заглавие : Ground-State Fermion Parity and Caloric Properties of a Superconducting Nanowire
Место публикации : J. Exp. Theor. Phys. - 2019. - Vol. 129, Is. 3. - P.426-437. - ISSN 10637761 (ISSN), DOI 10.1134/S1063776119080144
Примечания : Cited References: 74. - This work was supported by the Russian Foundation for Basic Research (project nos. 16-02-00073, 18-32-00443, 18-42-243017, 18-42-243018), the Government of the Krasnoyarsk Kray, the Krasnoyarsk Kray Science Foundation within the scientific projects “Contact Phenomena and Magnetic Disorder in the Formation and Detection of Topologically Protected Edge States in Semiconductor Nanostructures” (project no. 18-42-243018), “Manifestation of Coulomb Interactions and Bounded-Geometry Effects in the Properties of Topological Edge States of Nanostructures with Spin–Orbit Interactions” (project no. 18-42-243017). One of us (Sh. M. S.) thanks the Council for Grants of the Russian President (project nos. MK-3594.2018.2 and MK-3722.2018.2).
Аннотация: Abstract: The ground-state structure and fermion parity have been determined for a semiconductor nano-wire with a strong Rashba spin–orbit interaction and proximity-induced superconductivity placed in an external magnetic field under periodic boundary conditions. Allowance for the open boundaries is shown to cause the topologically nontrivial parameter region to be partitioned into a set of subregions with a different ground-state fermionic parity. This peculiarity is related to the emergence of edge modes with nonmonotonically changing excitation energies in the system as its parameters change. At the quantum transition point, at which the ground-state fermionic parity changes, the edge-mode energy is zero. The magneto- and electrocaloric effects are shown to be effective characteristics that allow the series of quantum transitions in an open nanowire to be identified experimentally. These effects at low temperatures exhibit an anomalous behavior in the parameter region for which topologically stable Majorana modes are realized in long nanowires. © 2019, Pleiades Publishing, Inc.
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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.
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Korshunov M. M., Gavrichkov V. A., Ovchinnikov S. G., Nekrasov I. A., Pchelkina Z. V., Anisimov V. I.
Заглавие : Hybrid LDA and generalized tight-binding method for electronic structure calculations of strongly correlated electron systems
Место публикации : Phys. Rev. B: AMERICAN PHYSICAL SOC, 2005. - Vol. 72, Is. 16. - Ст.165104. - ISSN 1098-0121, DOI 10.1103/PhysRevB.72.165104
Примечания : Cited References: 82
Предметные рубрики: T-J MODEL
DENSITY-FUNCTIONAL CALCULATION
NARROW ENERGY BANDS
MEAN-FIELD THEORY
COULOMB INTERACTIONS
FERMION SYSTEMS
COPPER OXIDES
SUPERCONDUCTORS
LA2-XSRXCUO4
OXYGEN
Аннотация: A hybrid scheme for the electronic structure calculations of strongly correlated electron systems is proposed. The ab initio local density approximation calculation is used to construct the Wannier functions and obtain single electron and Coulomb parameters of the multiband Hubbard-type model. In strong correlation regime the electronic structure within multiband Hubbard model is calculated by the generalized tight-binding method, which combines the exact diagonalization of the model Hamiltonian for a small cluster (unit cell) with perturbation treatment of the intercluster hopping and interactions. For undoped La2CuO4 and Nd2CuO4 this scheme results in charge transfer insulators with correct values of gaps and dispersions of bands in agreement with the angle-resolved photoemission data.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Lundin U., Sandalov I., Eriksson O., Johansson B.
Заглавие : Modification of the standard model for the lanthanides
Место публикации : Solid State Commun.: PERGAMON-ELSEVIER SCIENCE LTD, 2000. - Vol. 115, Is. 1. - P7-12. - ISSN 0038-1098, DOI 10.1016/S0038-1098(00)00126-5
Примечания : Cited References: 33
Предметные рубрики: ELECTRONIC-STRUCTURE CALCULATIONS
DENSITY-FUNCTIONAL THEORY
PARTICLE BAND-STRUCTURE
AB-INITIO CALCULATIONS
FERROMAGNETIC NICKEL
COHESIVE PROPERTIES
CRYSTAL-STRUCTURE
MOTT INSULATORS
FERMION SYSTEMS
PR METAL
Ключевые слова (''Своб.индексиров.''): metals--electronic band structure--band structure--elastic moduli--kohn-sham scheme--rare earth elements
Аннотация: We show that incorporation of strong electron correlations into the Kohn-Sham scheme of band structure calculations leads to a modification of the standard model of the lanthanides and that this procedure removes the existing discrepancy between theory and experiment concerning the ground state properties. Within the picture suggested, part of the upper Hubbard f-band is occupied due to conduction band-f-mixing interaction (that is renormalized due to correlations) and this contributes to the cohesive energy of the crystal. The lower Hubbard band has zero width and describes fermionic excitations in the shell of localized f-s. Fully self-consistent calculations (with respect to both charge density and many-electron population numbers of the f-shell) of the equilibrium volume V-0 and the bulk modulus of selected lanthanides have been performed and a good agreement with experiment is obtained. (C) 2000 Elsevier Science Ltd. All rights reserved.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Nikitin S. E., Nishimoto S., Fan Y., Wu J., Wu L. S., Sukhanov A. S., Brando M., Pavlovskii N. S., Xu J., Vasylechko L., Yu R., Podlesnyak A.
Заглавие : Multiple fermion scattering in the weakly coupled spin-chain compound YbAlO3
Место публикации : Nat. Commun. - 2021. - Vol. 12, Is. 1. - Ст.3599. - ISSN 20411723 (ISSN), DOI 10.1038/s41467-021-23585-z
Примечания : Cited References: 34. - We acknowledge C.D. Batista for fruitful discussions, U. Nitzsche for technical assistance, P.Y. Portnichenko for help with the neutron-scattering experiment, and B. Normand for insightful suggestions and careful proofreading of the manuscript. This research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by Oak Ridge National Laboratory. S.N. acknowledges support by the Deutsche Forschungsgemeinschaft through SFB 1143 project no. A05. S.E.N. and A.S.S. acknowledge support from the International Max Planck Research School for Chemistry and Physics of Quantum Materials (IMPRS-CPQM). The work at Renmin University was supported by the Ministry of Science and Technology of China, National Program on Key Research Project (grant number 2016YFA0300504), the National Science Foundation of China (grant number 11674392), and the Fundamental Research Funds for the Central Universities and the Research Funds of Renmin University of China (grant number 18XNLG24). J.W. acknowledges additional support from a Shanghai talent program. The work at Shanghai Jiao Tong University is sponsored by the Natural Science Foundation of Shanghai with grant no. 20ZR1428400 and Shanghai Pujiang Program with grant no. 20PJ1408100 (J.W)
Аннотация: The Heisenberg antiferromagnetic spin-1/2 chain, originally introduced almost a century ago, is one of the best studied models in quantum mechanics due to its exact solution, but nevertheless it continues to present new discoveries. Its low-energy physics is described by the Tomonaga-Luttinger liquid of spinless fermions, similar to the conduction electrons in one-dimensional metals. In this work we investigate the Heisenberg spin-chain compound YbAlO3 and show that the weak interchain coupling causes Umklapp scattering between the left- and right-moving fermions and stabilizes an incommensurate spin-density wave order at q = 2kF under finite magnetic fields. These Umklapp processes open a route to multiple coherent scattering of fermions, which results in the formation of satellites at integer multiples of the incommensurate fundamental wavevector Q = nq. Our work provides surprising and profound insight into bandstructure control for emergent fermions in quantum materials, and shows how neutron diffraction can be applied to investigate the phenomenon of coherent multiple scattering in metals through the proxy of quantum magnetic systems.
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