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

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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Parshin A. M., Zyryanov V. Ya., Shabanov V. F.
Заглавие : Optical transmission modulation and spectral properties of self-organized nematic domains
Колич.характеристики :6 с
Место публикации : Opt. Mater. - 2024. - Vol. 150. - Ст.115232. - ISSN 09253467 (ISSN), DOI 10.1016/j.optmat.2024.115232. - ISSN 18731252 (eISSN)
Примечания : Cited References: 24
Аннотация: The modulation and spectral characteristics of self-organized ensembles of nematic domains with the disclination lines non-aligned and aligned in a magnetic field have been studied using an electric field. The obtained experimental voltage dependences of the light transmission agree well with the dependences calculated using the model considerations. These dependences have been compared with the electro-optical characteristics of a homogeneous planar nematic layer. The amplitude component of the optical transmission determined by light scattering and the oscillating component caused by the phase modulation have been examined. The effect of the spectral dispersion of transmission on the electro-optical characteristics of domain ensembles has been evaluated.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Tikhomirov A. A., Molokeev M. S., Velichko V. V.
Заглавие : Photo-biological effectiveness of PAR for radish plant communities irradiated using an LED source with an adjustable spectrum
Колич.характеристики :8 с
Место публикации : Light Eng. - 2024. - Vol. 32, Is. 2. - P.70–77. - ISSN 02362945 (ISSN), DOI 10.33383/2023-063. - ISSN 25419935 (eISSN)
Примечания : Cited References: 15. - The study was carried out with financial support within the framework of State Assignment 121101300066-7 of the Ministry of Education and Science and the Strategic Academic Leadership Program "Priority-2030" for the Siberian Federal University
Аннотация: The aim of the current study was to find the most effective spectral modes of irradiation of short-season plants (for example, radish) using a fluorescent LED irradiator with a variable spectrum. The research methodology was based on the species-specific response of plants to the spectral composition of light. Photo-biological experiments were carried out to find effective spectral composition of PAR for cultivating radish communities under stable and variable irradiation modes of electrical lighting. It was shown that under stable irradiation modes, the highest productivity of economically useful radish biomass had been achieved at spectral composition with a maximum of 60 % radiation in the (600–700) nm region in a variable spectral irradiation mode. The variable spectral irradiation mode turned out to be the most effective when the spectral composition with the dominance of red rays was changed to the spectral composition with the dominance of blue rays. There were no significant differences between the best production parameters for stable and variable modes of irradiation of radish plants, which indicates the expediency of choosing the stable spectral mode of irradiation of radish plants as a short-season crop under electrical illumination. The results obtained can be used to select spectral irradiation modes for short-season plants grown under electrical lighting in northern regions and in isolated rooms in various climatic zones using "City-farm" technologies.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Krylova S. N.
Заглавие : Calculation of the phonon spectrum of PbMnBO4 crystal using density functional theory
Колич.характеристики :9 с
Место публикации : Crystallogr. Rep. - 2023. - Vol. 68, Is. 5. - P.788-796. - ISSN 10637745 (ISSN), DOI 10.1134/S1063774523600436. - ISSN 1562689X (eISSN)
Примечания : Cited References: 31. - This study was supported by the Russian Foundation for Basic Research, project no. 21-52-12018 NNIO_а
Аннотация: The phonon dispersion and Raman spectrum of the PbMnBO4 ferromagnetic crystal have been calculated within the density functional theory. Imaginary phonon branches have been observed at the points Y, Z, and Г and along the X–S direction of the Brillouin zone, which indicates structural instability and a possible phase transition with variation in external factors (temperature and pressure). The shapes of vibrations and symmetry types of the normal modes of the crystal at the center of the Brillouin zone have been determined. The calculation results are compared with the experimental and theoretical spectra from other studies. It is shown that the vibrational mode of highest intensity at 692.5 cm–1 in the spectrum and the mode at 272.3 cm–1, corresponding to the experimental modes at 690.5 and 224.7 cm–1, are bending vibrations of oxygen atoms in distorted MnO6 octahedra.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Oreshonkov A. S., Sukhanova E. V., Popov Z. I.
Заглавие : Phonon dynamics in MoSi2N4: insights from DFT calculations
Колич.характеристики :11 с
Место публикации : Phys. Chem. Chem. Phys. - 2023. - Vol. 25, Is. 43. - P.29831-29841. - ISSN 14639076 (ISSN), DOI 10.1039/D3CP02921B. - ISSN 14639084 (eISSN)
Примечания : Cited References: 74. - The authors acknowledge financial support from Russian Science Foundation (project №21-73-20183, https://rscf.ru/project/21-73-20183/)
Аннотация: We have reported the density functional theory investigations on the monolayer, 2 layered and bulk MoSi2N4 in three structural modifications called as α1 [Science, DOI: 10.1126/science.abb7023], α2 and α3 [Adv. Funct. Mater., DOI: 10.1002/adfm.202214050]. We showed that in the case of monolayers the difference in total energies is less than 0.1 eV between α1 and α3 phases, and less than 0.2 eV between α1 and α2 geometries. The most energetically favorable layer stacking for the bulk structures of each phase was investigated. All considered modifications are dynamically stable from a single layer to a bulk structure in energetically favorable stacking. Raman spectra for the monolayer, 2 layered and bulk structures were simulated and the vibrational analysis was performed. The main difference between in the obtained spectra is associated with the position of the strongest band which depends on the Mo-N bond length. According to the obtained data, we can conclude that Raman line at 348 cm–1 in the experimental spectra of MoSi2N4, can have more complex explanation then just Γ-point Raman-active vibration as was discussed before in [Science, DOI: 10.1126/science.abb7023].
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Orlov Yu. S., Nikolaev S. V., Kuz'min V. I., Zarubin A. E., Ovchinnikov S. G.
Заглавие : Excitonic ordering in strongly correlated spin crossover systems: Induced magnetism and excitonic excitation spectrum
Место публикации : Phys. Rev. B. - 2022. - Vol. 106, Is. 23. - Ст.235120. - ISSN 24699950 (ISSN), DOI 10.1103/PhysRevB.106.235120. - ISSN 24699969 (eISSN)
Примечания : Cited References: 50. - The authors thank the Russian Scientific Foundation for financial support under Grant No.18-12-00022
Аннотация: The effects associated with interatomic hoppings of excitons and the excitonic Bose condensate formation in strongly correlated spin crossover systems are considered in the framework of the effective Hamiltonian for the two-band Kanamori model. The appearance of antiferromagnetic ordering due to the exciton order is found even in the absence of interatomic exchange interaction. The spectrum of excitonic excitations is calculated at various points of the temperature vs crystal field phase diagram. Outside the region of exciton ordering, the spectrum has a gap, which vanishes at the boundary of the exciton condensate phase. The nonuniform spectral weight distribution over the Brillouin zone is found. The role of electron-phonon interaction is discussed as well.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Orlov V. A., Patrin G. S., Orlova I. N.
Заглавие : Spectrum of collective vibrations of vortex domain walls in a ferromagnetic nanostripe array
Место публикации : Eur. Phys. J. B. - 2022. - Vol. 95, Is. 3. - Ст.52. - ISSN 14346028 (ISSN), DOI 10.1140/epjb/s10051-022-00315-y
Примечания : Cited References: 32. - The study was carried out within the state assignment of the Ministry of Science and Higher Education of the Russian Federation, theme no. FSRZ-2020-0011
Аннотация: A problem of the spectrum of the collective periodic motion of vortex domain walls in a system of parallel ferromagnetic nanostripe is theoretically solved. The magnetic subsystems of stripes are coupled by the magnetostatic interaction. The effect of the distribution of vortex core polarities and chiralities on the character of periodic motion and the spectrum of collective modes of the nanostripe magnetization is discussed. Analytical expressions for the dispersion law and damping parameter of the collective periodic motion of vortex domain walls are obtained.
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Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Hoffman A. E. J., Senkovska I., Krylov A. S., Kaskel S., Speybroeck V. V.
Заглавие : Unfolding the terahertz spectrum of soft porous crystals: rigid unit modes and their impact on phonon properties
Коллективы : International Conference on Metal-Organic Frameworks and Open Frameworks Compounds
Место публикации : International Conference on Metal-Organic Frameworks and Open Frameworks Compounds (MOF 2022): book of abstracts. - 2022. - P.254
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Val'kov V. V.
Заглавие : Excitation spectrum in an ensemble of Hubbard bosons
Место публикации : JETP Lett. - 2022. - Vol. 116, Is. 12. - P.896-901. - ISSN 00213640 (ISSN), DOI 10.1134/S0021364022602664. - ISSN 10906487 (eISSN)
Примечания : Cited References: 25
Аннотация: An approach that makes it possible to correctly derive equations describing the Bose–Einstein condensation and the spectrum of elementary excitations in the ensemble of Hubbard bosons in the strong correlation regime (U≫|tfm|) has been developed in the atomic representation using the Dyson method with the introduced indefinite metric. The kinematic Dyson interaction caused by the properties of the commutation relations of dynamic variables plays an important role in such a system. An effective Hamiltonian has been obtained using the operator form of perturbation theory at finite U values. It has been shown that the properties of the ensemble of Hubbard bosons have been determined by the kinematic interaction, correlated hopping, and the attraction between Hubbard bosons. Numerical calculations have demonstrated the effect of these interactions on the characteristics of the energy spectrum of excitations of the ensemble of Hubbard bosons and on the dependence of the density of condensate particles on the density of bosons in the system.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gao P., Li Q., Li S., Gai S., Li Y., Ma Y., Zhang Z., Molokeev M. S., Zhou Z., Xia M.
Заглавие : Multiple strategies to approach high-efficiency luminescence controllable in blue/cyan/green-emitting Bi3+-activated phosphors
Место публикации : J. Phys. Chem. C. - 2022. - Vol. 126, Is. 21. - P.9195-9206. - ISSN 19327447 (ISSN), DOI 10.1021/acs.jpcc.2c02560
Примечания : Cited References: 53. - The authors would like to gratefully acknowledge funds from the National Natural Science Foundation of China (grant no. 51974123), the Distinguished Youth Foundation of Hunan Province (grant no.2020JJ2018), the Key R&D projects in Hunan Province (2020WK2016, 2020SK2032, 2021SK2047, and 2022NK2044), the Natural Science Foundation of Hunan Province, China (grant no. 2021JJ40261), the Hunan High Level Talent Gathering Project (2019RS1077 and 2020RC5007), the Scientific Research Fund of Hunan Provincial Education Department (19C0903), the Natural Sciences Foundation of Hunan Agricultural University, China (grant no. 19QN11), the Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Resource Utilization Science Foundation (19KFXM12), the Changsha Science and Technology Plan (KH2005114, KH2201428), and the College Students’ Innovative Training (S202110537012)
Аннотация: Cyan gap is a major block in achieving high-quality white light-emitting diodes (WLEDs). Hence, a novel cyan-emitting phosphor Sr2GdGaO5/0.02Bi3+ with optical tuning performance is synthesized based on the local crystal field regulation strategy surrounding the luminescence center. With the substitution of Al3+ for Ga3+, the photoluminescence (PL) spectra of Sr2GdGa1–xAlxO5/0.02Bi3+ (0 ≤ x ≤ 1) phosphors adjust from cyan (466 nm) to blue (450 nm). Moreover, such a Ba2+ doping adjusts the PL spectra of Sr2–xBaxGdGaO5/0.02Bi3+ (0 ≤ x ≤ 0.5) phosphors from cyan (466 nm) to green (482 nm). These phenomena are contributed to the crystal field splitting and nephelauxetic effect. The energy transfer from Bi3+ to Eu3+ is realized by co-doping Bi3+ and Eu3+ ions in the A2GdBO5/Bi3+ (A = Sr, Ba; B = Ga, Al) host materials, and two single-phase white phosphors Sr2GdGaO5/0.02Bi3+, 0.05Eu3+ and Sr1.5Ba0.5GdGaO5/0.02Bi3+, 0.05Eu3+ are obtained. Finally, a WLED with high color rendering index (Ra = 93.6) is prepared by using red/green/blue (RGB) phosphors and Sr2GdGaO5/0.02Bi3+ phosphor, which is higher than that of the WLED prepared by RGB phosphors (Ra = 86.7), indicating that Sr2GdGaO5/0.02Bi3+ phosphor can close the cyan gap. These results provide multiple strategies in achieving luminescence controllable and WLED.
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10.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Aksenov S. V., Fedoseev A. D., Shustin M. S., Zlotnikov A. O.
Заглавие : Effect of weak hubbard repulsion on spectrum and transport in higher-order topological superconductor
Коллективы : Российская академия наук, Физико-технический институт им. Е.К. Завойского ФИЦ Казанского научного центра РАН, Казанский (Приволжский) федеральный университет, Euro-Asian Symposium "Trends in MAGnetism", "Trends in MAGnetism", Euro-Asian Symposium
Место публикации : VIII Euro-Asian symposium "Trends in magnetism" (EASTMAG-2022): Book of abstracts/ program com. S. G. Ovchinnikov [et al.]. - 2022. - Vol. 2, Sect. I: Magnetism and superconductivity. - Ст.I.P1. - P.153-154. - ISBN 978-5-94469-051-7
Примечания : Cited References: 5. - The study was supported by Russian Science Foundation, project 22-22-20076
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Orlov V. A., Prokopenko V. S., Rudenko R. Y., Orlova I. N.
Заглавие : Low-frequency spectrum of the gyrotropic modes of a finite chain of interacting ferromagnetic disks
Место публикации : Tech. Phys. - 2022. - Vol. 67, Is. 4. - P.289-296. - ISSN 10637842 (ISSN), DOI 10.1134/S1063784222050085
Примечания : Cited References: 34. - This study was financially supported by the Russian Foundation for Basic Research, project no. 20-02-00696
Аннотация: The problem of the frequency spectrum of collective gyrotropic modes in a finite linear chain of magnetostatically interacting ferromagnetic disks has been considered. It has been shown that by analyzing the frequency spectrum, one can derive information about the magnetization eddy state for each of the nanodisks in the chain. The feasibility of recording the frequency spectrum as a tool for data readout in magnetic memory devices has been discussed.
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Hoffman A. E.J., Senkovska I., Wieme J., Krylov A. S., Kaskel S., Van Speybroeck V.
Заглавие : Unfolding the terahertz spectrum of soft porous crystals: rigid unit modes and their impact on phase transitions
Место публикации : J. Mater. Chem. A. - 2022. - Vol. 10, Is. 33. - P.17254-17266. - ISSN 20507488 (ISSN), DOI 10.1039/d2ta01678h
Примечания : Cited References: 80. - This work was financially supported by the Fund for Scientific Research Flanders (FWO), the Research Board of the Ghent University (BOF), the Deutsche Forschungsgemeinschaft (DFG, project number 448809307), and the Russian Foundation for Basic Research (RFBR, project number 21-52-12018). The authors thank Kerstin Zechel for sample synthesis. The computational resources and services used in this work were provided by the Flemish Supercomputer Center (VSC), funded by FWO and the Flemish Government
Аннотация: Phase transitions in flexible metal-organic frameworks or soft porous crystals are mediated by low-frequency phonons or rigid-unit modes. The alteration of specific building blocks may change the lattice dynamics of these frameworks, which can influence the phase transition mechanism. In this work, the impact of building block substitution on the rigid-unit modes in flexible MIL-53 analogs with a winerack topology will be investigated via ab initio lattice dynamics calculations. First, the accuracy of the theoretical simulations is verified via experimental Raman measurements, which provide unique fingerprint vibrations in the terahertz range to characterize the phase transition. Following analysis of the low-frequency vibrations shows that there exists a set of universal rigid-unit modes inducing translations and/or rotations of the building blocks. The theoretical results demonstrate that linker substitutions have a large effect on the rigid-unit mode frequencies, whereas this is less so for inorganic chain substitutions. These findings may help to rationally tune the phonon frequencies in soft porous crystals.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Orlov Yu. S., Dudnikov V. A., Sokolov A. Е., Ovchinnikova T. M., Shestakov N. P., Ovchinnikov S. G.
Заглавие : Fluctuations of the multiplicity of Co3+ ions and softening of the phonon spectrum of rare-earth cobalt oxides
Место публикации : JETP Letters. - 2022. - Vol. 115, Is. 10. - P.615-619. - ISSN 00213640 (ISSN), DOI 10.1134/S0021364022100575
Примечания : Cited References: 25. - This work was supported by the Russian Science Foundation (project no. 18-12-00022)
Аннотация: An unconventional temperature dependence of infrared absorption spectra of rare-earth cobalt oxides LaCoO3 and GdCoO3 has been studied experimentally and theoretically in the temperature range of 3.2–550 K. A quite strong softening of the optical phonon mode has been detected, which cannot be explained by standard lattice anharmonicity. It has been shown that the redshift of the phonon spectrum is due to the e-lectron–phonon coupling quadratic in the lattice displacement and to fluctuations of the multiplicity of Co3+ ions.
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gai S. J., Zhou C., Peng L., Wu M. H., Gao P. X., Su L. J., Molokeev M. S., Zhou Z., Xia M.
Заглавие : A novel Cr3+-doped stannate far red phosphor for plant lighting: structure evolution, broad-narrow spectrum tuning and application prospect
Место публикации : Mater. Today Chem. - 2022. - Vol. 26. - Ст.101107. - ISSN 24685194 (ISSN), DOI 10.1016/j.mtchem.2022.101107
Примечания : Cited References: 50. - The authors would like to gratefully acknowledge funds from the National Natural Science Foundation of China (Grant No. 51974123), the Distinguished Youth Foundation of Hunan Province (Grant No.2020JJ2018), the Key R & D projects in Hunan Province (2020WK2016, 2020SK2032, 2021SK2047, 2022NK2044), the Natural Science Foundation of Hunan Province, China (Grant No. 2021JJ40261), the Hunan High Level Talent Gathering Project (2019RS1077&2020RC5007), the Scientific Research Fund of Hunan Provincial Education Department (19C0903), the Natural Sciences Foundation of Hunan Agricultural University, China (Grant No. 19QN11), Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Resource Utilization Science Foundation (19KFXM12), Changsha Science and technology plan (KH2005114 and KH2201428), the Hunan Graduate Scientific Research Innovation Project (2022XC017) and the College Students' Innovative Training (S202110537012 and s202210537079x)
Аннотация: Chemical unit cosubstitution is an effective strategy to regulate the luminescence properties of phosphors, and it has attracted huge attention in the last few years. Following the design principles of the match of effective ion radius, atomic valence equilibrium and stoichiometric substitution, the local structure of crystal can be well customized, which is beneficial to develop high-performance luminescent materials. In this work, Mg2+-Sn4+ sites were cosubstituted by Zn2+-Ti4+ ion pairs in Mg2SnO4: Cr3+, respectively, and the emission spectra was successfully serially tuned from broad-band to narrow-band along with a unique variation trend of blue shift first and then slightly red shift. The photoluminescence excitation (PLE), photoluminescence (PL) spectra, lifetime decay, Raman spectra and electron paramagnetic resonance (EPR) were used to analyze the mechanism of luminescence tuning. Based on the manipulation of local structure, the as-observed distinct luminescence tuning can be well understood by the crystal field theory, nephelauxetic effect and changed Cr3+ capacity in this phosphor. Moreover, the adjusted narrow-band far-red emission spectra peak at 732 nm, matching the characteristic absorption of plant phytochrome PFR, has broad application prospects in the field of plant growth lighting. In addition, light-regulated dwarf potted tomato experiments were carried out to verify the application of far-red light in plant growth.
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Aplesnin S. S., Masyugin A. N., Kretinin V. V., Konovalov S. O., Shestakov N. P.
Заглавие : Magnetoresistance and IR spectrum of impurity states in the Ce3Fe5O12 film
Место публикации : Phys. Solid State. - 2021. - Vol. 63, Is. 2. - P.242-247. - ISSN 10637834 (ISSN), DOI 10.1134/S1063783421020025
Примечания : Cited References: 28. - This study was supported by the Russian Foundation for Basic Research, the Government of the Krasnoyarsk Krai, and the Krasnoyarsk Territorial Foundation for Support of Scientific and R&D Activities, project no. 18-42-240001 “Inversion of the Sign of Magnetoelectric Tensor Components with Temperature in the Neodymium-Doped Bismuth Iron Garnet Films”
Аннотация: In polycrystalline cerium iron garnet films, the gap in the electron excitation spectrum and electronic transitions between di- and tetravalent iron and cerium impurity ions have been established from the IR absorption spectra. The temperatures of delocalization of the ferrous states of iron have been found from the impedance spectroscopy, electrical resistance, and IR spectroscopy data. The difference between the ac and dc magnetoresistances has been established and explained using a model of a dielectrically inhomogeneous medium.
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Tomilin F. N., Rogova A. V., Burakova L. P., Tchaikovskaya O. N., Avramov P. V., Fedorov D. G., Vysotski E. S.
Заглавие : Unusual shift in the visible absorption spectrum of an active ctenophore photoprotein elucidated by time-dependent density functional theory
Коллективы : RFBRRussian Foundation for Basic Research (RFBR) [20-04-00085]; NSFCNational Natural Science Foundation of China (NSFC) [19-54-53004]; Russian Ministry of Science and EducationMinistry of Education and Science, Russian Federation [0721-2020-0033]
Место публикации : Photochem. Photobiol. Sci. - 2021. - Vol. 20, Is. 4. - P.559-570. - ISSN 1474-905X, DOI 10.1007/s43630-021-00039-5. - ISSN 1474-9092(eISSN)
Примечания : Cited References: 61. - The ab initio quantum chemical calculations were funded by RFBR and NSFC as the research project No. 19-54-53004 and RFBR research project No. 20-04-00085. The development of structural atomistic model of berovin without calcium ions generated by the I-TASSER server was funded by project 0721-2020-0033 of the Russian Ministry of Science and Education
Аннотация: Active hydromedusan and ctenophore Ca2+-regulated photoproteins form complexes consisting of apoprotein and strongly non-covalently bound 2-hydroperoxycoelenterazine (an oxygenated intermediate of coelenterazine). Whereas the absorption maximum of hydromedusan photoproteins is at 460–470 nm, ctenophore photoproteins absorb at 437 nm. Finding out a physical reason for this blue shift is the main objective of this work, and, to achieve it, the whole structure of the protein–substrate complex was optimized using a linear scaling quantum–mechanical method. Electronic excitations pertinent to the spectra of the 2-hydroperoxy adduct of coelenterazine were simulated with time-dependent density functional theory. The dihedral angle of 60° of the 6-(p-hydroxy)-phenyl group relative to the imidazopyrazinone core of 2-hydroperoxycoelenterazine molecule was found to be the key factor determining the absorption of ctenophore photoproteins at 437 nm. The residues relevant to binding of the substrate and its adopting the particular rotation were also identified.
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Boldyrev K. N., Burlakov V. M., Gudim I. A., Gavrilkin S. Y., Popova M. N.
Заглавие : Regulation of the phase transition temperature and hysteresis width by changing the composition of solid solution
Место публикации : Phys. Rev. Mater. - 2021. - Vol. 5, Is. 9. - Ст.094414. - ISSN 24759953 (ISSN), DOI 10.1103/PhysRevMaterials.5.094414
Примечания : Cited References: 52. - This work is supported by the Russian Science Foundation under Grant No. 19-12-00413
Аннотация: A detailed study of the structural phase transition in Eu1–xLaxFe3(BO3)4 mixed crystals as a function of composition is reported. By analyzing a frequency shift of an electronic f-f transition in high-resolution optical spectra of Eu3+ ions, we detected a decrease in the phase transition temperature Ts from 87.05 to 12.2 K (upon cooling) and a simultaneous increase in thermal hysteresis ΔTs from 0.29 to 4.7 K with increasing x from x=0 to x=0.12. A rectangular hysteresis loop was observed. The experimental Ts(x) and ΔTs(x) dependences are described within the developed analytical model utilizing linear decrease in Ts with x and treating the increase in ΔTs in terms of the impurity-related decrease in the interaction between some local order parameters. We argue that R1−xR′xFe3(BO3)4 solid solutions, where R and R′ are different rare-earth elements, can be used to implement optical storage devices and switches operating at any chosen temperature between 0 and 450 K. It is found that the changes in the composition and, correspondingly, structural phase transition parameters do not affect the magnetic phase transformation. Eu0.88La0.12Fe3(BO3)4 demonstrates the structural phase transition at about 12 K, well below the Néel temperature TN=32K.
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Karnachuk O. V., Ikkert O. P., Avakyan M. R., Knyazev Yu. V., Volochaev M. N., Zyusman V. S., Panov V. L., Kadnikov V. V., Mardanov A. V., Ravin N. V.
Заглавие : Desulfovibrio desulfuricans AY5 isolated from a patient with autism spectrum disorder binds iron in low-soluble greigite and pyrite
Место публикации : Microorganisms. - 2021. - Vol. 9, Is. 12. - Ст.2558. - ISSN 20762607 (ISSN), DOI 10.3390/microorganisms9122558
Примечания : Cited References: 43. - This research was partly supported by the Russian Foundation for Basic Research (project # 20-34-70051 to O.P.I.)
Аннотация: The sulphate-reducing bacteria (SRB) of genus Desulfovibrio are a group of prokaryotes associated with autism spectrum disorders (ASD). The connection between the elevated numbers of Desulfovibrio in the gut of children with ASD compared with healthy children remains unresolved. A conceivable consequence of SRB overgrowth in the gut is the conversion of bioavailable iron into low-soluble crystalline iron sulphides, causing iron deficiency in the organism. In this study, we report the draft genome sequence and physiological features of the first cultivable isolate from a patient with ASD, Desulfovibrio desulfuricans strain AY5.The capability of the strain to produce crystalline iron sulphides was studied under different pH conditions. The most notable greigite(Fe3S4) and pyrite (FeS2) formation was revealed at pH 6.0, which suggests that the iron loss due to insoluble sulphide formation may occur in the proximal part of the gastrointestinal tract. Strain AY5 was adapted to grow under nitrogen-limiting conditions by N2 fixation. The urease found in the strain’s genome may play a role in resistance to acidic pH.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Val'kov V. V.
Заглавие : Splitting of the spectrum of fermionic excitations in a topological insulator by charge fluctuations
Коллективы : Russian Foundation for Basic ResearchRussian Foundation for Basic Research (RFBR) [19-02-00348]
Место публикации : JETP Letters. - 2021. - Vol. 114, Is. 12. - P.751-756. - ISSN 0021-3640, DOI 10.1134/S0021364021240097. - ISSN 1090-6487(eISSN)
Примечания : Cited References: 22. - This work was supported by the Russian Foundation for Basic Research (project no. 19-02-00348)
Предметные рубрики: HUBBARD FERMIONS
EDGE STATES
PHASE
SURFACE
Аннотация: It is shown that the intersite Coulomb interaction of electrons in a topological insulator leads to the splitting of the initial energy structure and to the induction of two bands of fluctuation states. As a result, the total spectrum of Fermi excitations of the topological insulator has a four-band structure. The dielectric gap is determined by the energy interval between the bottom of the band of fluctuation states of conduction electrons and the top of the valence band of fluctuation states. Since the band of fluctuation states is narrow, quasiparticles with different effective masses appear.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Avdeeva A. Yu., Vetrov S. Ya., Timofeev I. V.
Заглавие : Splitting of a Tamm plasmon polariton at the interface between a metal and a resonant nanocomposite layer conjugated with a photonic crystal
Место публикации : J. Opt. Soc. Am. B. - 2021. - Vol. 38, Is. 6. - P.1792-1797. - ISSN 07403224 (ISSN), DOI 10.1364/JOSAB.420490
Примечания : Cited References: 36. - The reported study was funded by Russian Foundation for Basic Research, Government of Krasnoyarsk Territory, Krasnoyarsk Region Science and Technology Support Fund to the research project No. 19-42-240004 and by Russian Foundation for Basic Research, project No. 19-52-52006. The authors are thankful to Pavel S. Pankin for valuable discussions and comments
Аннотация: Splitting of a Tamm plasmon polariton at the interface between a metal and a nanocomposite layer conjugated with a photonic crystal (Bragg mirror) has been theoretically investigated. The splitting can be implemented when the Tamm plasmon polariton frequency approaches the resonance frequency of the nanocomposite, which consists of metallic nanoballs dispersed in a transparent matrix. The reflectance spectrum of the p-polarized waves at the normal incidence of light has been calculated. It has been established that the Tamm plasmon polariton splitting significantly depends on the concentration of nanoballs in the nanocomposite layer and its thickness. The solution of the dispersion equation derived for a sample with semi-infinite mirrors has been compared with the spectra obtained for a finite structure by the transfer matrix method.
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