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Лукьянов, Александр Евгеньевич

Организационные подразделения

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Институт лазерных и плазменных технологий

Стратегическая цель Института ЛаПлаз – стать ведущей научной школой и ядром развития инноваций по лазерным, плазменным, радиационным и ускорительным технологиям, с уникальными образовательными программами, востребованными на российском и мировом рынке образовательных услуг.

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Лукьянов

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Александр Евгеньевич

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Теперь показываю 1 - 10 из 19

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Electronic properties and X-ray absorption spectra of Ba1-xKxBiO3
(2019) Zhumagulov, Y.; Krasavin, A.; Lukyanov, A.; Neverov, V.; Yaroslavtsev, A. A.; Menushenkov, A. P.; Красавин, Андрей Валерьевич; Лукьянов, Александр Евгеньевич; Неверов, Вячеслав Дмитриевич; Менушенков, Алексей Павлович
© Published under licence by IOP Publishing Ltd.The band structure, the density of states, and X-ray absorption spectra of the oxygen K-edge for perovskite high-temperature superconductors based on BaBiO3 are calculated by the density functional theory method for different levels of potassium doping in the ground and optically excited states. It is shown that changes in the properties of the electronic subsystem near the Fermi level can be correctly described by taking into account local structural inhomogeneities caused by doping and exposure to optical radiation. The appearance with doping of hole carriers on the hybridized Bi6s - O2p σ∗ orbital is demonstrated, which agrees with the model of the electronic structure of bismuthate high-temperature superconductors based on a spatially separated Fermi-Bose mixture.
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Symmetry of superconducting order parameter in minimal model of iron-based HTSC: Variational cluster approximation
(2019) Zhumagulov, Y.; Lukyanov, A.; Neverov, V.; Krasavin, A.; Лукьянов, Александр Евгеньевич; Неверов, Вячеслав Дмитриевич; Красавин, Андрей Валерьевич
© 2019 Published under licence by IOP Publishing Ltd. Two-orbital model describing iron-based high-temperature superconductors is studied within the limits of variational cluster approximation. It is found that in the undoped regime the stripe antiferromagnetic ordering is realized, while in doped regime antiferromagnetism and superconductivity coexist. In the superconducting state, two types of symmetry are found: extended inter-orbit s-wave and intra-orbit d-wave, in agreement with known experimental results.
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Antiferromagnetic and spectral properties of two-orbital model of iron-based HTSC
(2019) Neverov, V.; Lukyanov, A.; Zhumagulov, Y.; Krasavin, A.; Неверов, Вячеслав Дмитриевич; Лукьянов, Александр Евгеньевич; Красавин, Андрей Валерьевич
© 2019 Published under licence by IOP Publishing Ltd. Two-orbital model describing iron-based high-temperature superconductors was studied within the limits of variational cluster approximation. The electron density of states for each orbital, as well as momentum distribution, were calculated; the magnetic ordering was determined. The results obtained are in a good agreement with known experimental data.
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Estimation of electron-phonon coupling constant in Ba1-xKxBiO3
(2020) Lukyanov, A. E.; Neverov, V. D.; Krasavin, A. V.; Menushenkov, A. P.; Лукьянов, Александр Евгеньевич; Неверов, Вячеслав Дмитриевич; Красавин, Андрей Валерьевич; Менушенков, Алексей Павлович
© Published under licence by IOP Publishing Ltd.The Holstein model was used to determine the value of electron-phonon coupling in BaBiO3-based compounds in the framework of the dynamical mean-field theory calculations for various levels of doping with potassium. The results obtained characterize the electron-phonon interaction as strong. The phase diagram of the model was calculated with reference to experimental data.
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Polaronic signatures in pristine phosphorene
(2021) Perebeinos, V.; Neverov, V. D.; Lukyanov, A. E.; Zhumagulov, Y. V.; Krasavin, A. V.; Неверов, Вячеслав Дмитриевич; Лукьянов, Александр Евгеньевич; Красавин, Андрей Валерьевич
©2021 American Physical Society.We investigate polaronic effects in a monolayer black phosphorus (or phosphorene) due to the charge carrier-intrinsic phonons interaction. We employ a microscopic model to describe vibrational spectra and electron-phonon interactions within the tight-binding approach. Our adiabatic solution for polarons suggests the critical coupling constant of λc=3.0 for polaron self-trapping in this anisotropic material. We report nonadiabatic calculations for the band-gap renormalization and the effective mass enhancement as a function of temperature and a range of electron-phonon coupling strengths. Our results demonstrate a surprising large band-gap renormalization, even for the lower bound of the electron-phonon coupling strength reported in the literature. We find that optical phonons give the dominant contributions to the polaronic effect.
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Effect of Optical Excitation on the Band Structure and X-Ray Absorption Spectra of BaBiO3-Based High-Temperature Superconductors: Ab Initio Calculation
(2019) Zhumagulov, Y. V.; Krasavin, A. V.; Lukyanov, A. E.; Neverov, V. D.; Yaroslavtsev, A. A.; Menushenkov, A. P.; Красавин, Андрей Валерьевич; Лукьянов, Александр Евгеньевич; Неверов, Вячеслав Дмитриевич; Менушенков, Алексей Павлович
© 2019, Pleiades Publishing, Inc.The band structure, densities of states, and O K-edge X-ray absorption spectra have been calculated by the density functional theory method for BaBiO3-based perovskite high-temperature superconductors at different potassium doping levels in the ground and optically excited states. It has been shown that this approach including local structural inhomogeneities caused by doping and optical irradiation allows the correct description of changes in the properties of the electron subsystem near the Fermi level. It has been shown that doping is accompanied by the appearance of hole carriers on the Bi6s−O2pσ*. hybridized orbital in agreement with the model of the electronic structure of bismuth-based high-temperature superconductors in terms of a spatially separated Fermi-Bose mixture. It has been found that the band structure for the excited state of the undoped compound is equivalent to the band structure of the tight binding model for a cubic lattice. The results are important for the preliminary analysis of time-resolved X-ray absorption spectra on an X-ray free electron laser at femtosecond optical excitation.
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Correlated disorder as a way towards robust superconductivity
(2022) Vagov, A.; Croitoru, M. D.; Neverov, V. D.; Lukyanov, A. E.; Krasavin, A. V.; Неверов, Вячеслав Дмитриевич; Лукьянов, Александр Евгеньевич; Красавин, Андрей Валерьевич
© 2022, The Author(s).Ordinary superconductors are widely assumed insensitive to small concentrations of random nonmagnetic impurities, whereas strong disorder suppresses superconductivity and even makes superconductor-insulator transition occur. In between these limiting cases, a most fascinating regime can take place where disorder enhances superconductivity. Hitherto, almost all theoretical studies have been conducted under the assumption that disorder is completely independent and random. In real materials, however, positions of impurities and defects tend to correlate with each other. This work shows that these correlations have a strong impact on superconductivity making it more robust and less sensitive to the disorder potential. Superconducting properties can therefore be controlled not only by the overall density of impurities and defects, but by their spatial correlations as well.
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Exploring disorder correlations in superconducting systems: spectroscopic insights and matrix element effects
(2024) Neverov, V. D.; Lukyanov, A. E.; Krasavin, A. V.; Vagov, A.; Неверов, Вячеслав Дмитриевич; Лукьянов, Александр Евгеньевич; Красавин, Андрей Валерьевич
Только метаданные
Nonlinear spectroscopy of excitonic states in transition metal dichalcogenides
(2022) Zhumagulov, Y. V.; Gulevich, D. R.; Vagov, A.; Perebeinos, V.; Neverov, V. D.; Lukyanov, A. E.; Krasavin, A. V.; Неверов, Вячеслав Дмитриевич; Лукьянов, Александр Евгеньевич; Красавин, Андрей Валерьевич
© 2022 American Physical Society.Second-harmonic generation (SHG) is a well-known nonlinear spectroscopy method to probe electronic structure, specifically, in transition metal dichalcogenide (TMDC) monolayers. This work investigates the nonlinear dynamics of a strongly excited TMDC monolayer by solving the time evolution equations for the density matrix. It is shown that the presence of excitons qualitatively changes the nonlinear dynamics leading, in particular, to a huge enhancement of the nonlinear signal as a function of the dielectric environment. It is also shown that the SHG polarization angular diagram and its dependence on the driving strength are very sensitive to the type of exciton state. This sensitivity suggests that SHG spectroscopy is a convenient tool for analyzing the fine structure of excitonic states.
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Phase Diagram of the Two-Orbital Model for Iron-Based HTSC: Variational Cluster Approximation
(2019) Zumagulov, Y. V.; Kashurnikov, V. A.; Krasavin, A. V.; Lukyanov, A. E.; Neverov, V. D.; Кашурников, Владимир Анатольевич; Красавин, Андрей Валерьевич; Лукьянов, Александр Евгеньевич; Неверов, Вячеслав Дмитриевич
The phase diagram of the two-dimensional two-orbital Hubbard model, which is widely used to describe high-temperature iron-based superconductors, is calculated in the electron doping region using the method of the variational cluster approximation. It is found that the coexistence of the antiferromagnetic and superconducting phases is realized in a wide range of electron doping values. In the superconducting phase, the order parameter has s(+/-) symmetry.