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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 18

Только метаданные
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.
Только метаданные
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.
Только метаданные
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.
Только метаданные
Оценка константы электрон-фононного взаимодействия в соединениях ВКВО
(2020) Лукьянов, А. Е.; 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.
Только метаданные
Strength of the Hubbard potential and its modification by breathing distortion in BaBiO3
(2022) Lukyanov, A. E.; Kovalev, I. A.; Neverov, V. D.; Zhumagulov, Y. V.; Krasavin, A. V.; Лукьянов, Александр Евгеньевич; Неверов, Вячеслав Дмитриевич; Красавин, Андрей Валерьевич
BaBiO3 compound is known as an archetype example of a three-dimensional Holstein model with the realization of the charge-density wave state at half filling and the superconducting state when doped. Although many works are devoted to the study the electron-phonon interaction in BaBiO3, the influence of the electron-electron Hubbard interaction on the electronic structure in this system is still under investigation. In our work, we obtain analytical expression for the screened Coulomb potential, and along with the basis of ab initio-computed maximally localized Wannier orbitals, we quantitatively estimate the magnitude of the effective on-site Hubbard potential scrutinizing the effects of distortion of the crystal lattice. We show that a proper inclusion of the electron-electron interactions into the Holstein model significantly lowers the value of the underlying electron-phonon coupling. Finally, we find that the amplitudes of the repulsive electron-electron potential and its attractive counterpart mediated by the electron-phonon coupling are rather comparable. This may open a way for a realization of the intermediate phase of BaBiO3 in terms of the Holstein-Hubbard model.
Только метаданные
Laser-induced ultrafast insulator-metal transition in BaBiO3
(2020) Lukyanov, A. E.; Neverov, V. D.; Zhumagulov, Y. V.; Menushenkov, A. P.; Krasavin, A. V.; Лукьянов, Александр Евгеньевич; Неверов, Вячеслав Дмитриевич; Менушенков, Алексей Павлович; Красавин, Андрей Валерьевич
We investigate ultrafast coherent quantum dynamics of undoped BaBiO3 driven by a strong laser pulse. Our calculations demonstrate that in a wide range of radiation frequencies and intensities the system undergoes a transient change from the insulating to the metallic state, where the charge density wave and the corresponding energy spectrum gap vanish. The transition takes place on the ultrafast timescale of tens femtoseconds, comparable to the period of the corresponding lattice vibrations. The dynamics are determined by a complex interplay of the particle-hole excitation over the gap and of the tunneling through it, giving rise to the highly nontrivial time evolution which comprises high harmonics and reveals periodic reappearance of the gap. The time evolution is obtained by solving the dynamical mean-field theory equations with the realistic parameters for the system and radiation. Results are summarized in the phase diagram, helpful for a possible experimental setup to achieve a dynamical control over the conduction state of this and other materials with the similarly strong electron-phonon interaction.
Только метаданные
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.
Только метаданные
Direct evidence of real-space pairing in BaBiO3
(2024) Menushenkov, A. P.; Ivanov, A.; Neverov, V.; Lukyanov, A.; Krasavin, A.; Yastrebtsev, A. A.; Kovalev, I. A.; Kuznetsov, A. V.; Popov, V.; Krymskaya, O.; Менушенков, Алексей Павлович; Иванов, Андрей Анатольевич; Неверов, Вячеслав Дмитриевич; Лукьянов, Александр Евгеньевич; Красавин, Андрей Валерьевич; Ястребцев, Алексей Алексеевич; Кузнецов, Алексей Владимирович; Попов, Виктор Владимирович; Крымская, Ольга Александровна
Только метаданные
The Impact of Short-Range (Gaussian) Disorder Correlations on Superconducting Characteristics
(2024) Neverov, V. D.; Lukyanov, A. E.; Krasavin, A. V.; Vagov, A.; Неверов, Вячеслав Дмитриевич; Лукьянов, Александр Евгеньевич; Красавин, Андрей Валерьевич