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 (22)

Формат представления найденных документов:
полный	информационный	краткий

Отсортировать найденные документы по:
автору	заглавию	году издания	типу документа

Поисковый запрос: (<.>K=SYMMETRY<.>)

Общее количество найденных документов : 116
Показаны документы с 1 по 20

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Golovkina E. V., Krylova S. N., Vtyurin A. N., Krylov A. S.
Заглавие : Analyzing the symmetry of the Raman spectra of crystals according to angular dependences
Колич.характеристики :6 с
Место публикации : Bull. Russ. Acad. Sci. Phys. - 2024. - Vol. 88, Is. 5. - P.773-778. - ISSN 10628738 (ISSN), DOI 10.1134/S1062873824706573. - ISSN 19349432 (eISSN)
Примечания : Cited References: 32. - This work was supported by the Russian Foundation for Basic Research, project no. 21-52-12018. The authors are grateful to Dr. Irena Senkovska for providing our DUT-8(Ni) samples
Аннотация: The authors propose a way of reconstructing the Raman tensor by studying the angular dependences of the intensities of the Raman lines of unoriented microcrystals. The technique is verified using familiar calomel Hg2Cl2 crystals. It is shown that the lines on DUT-8 (Ni) crystals indicating phases with open and closed pores have different types of symmetries. The technique can be used to reconstruct the Raman tensor for any unoriented crystalline sample.
Смотреть статью
Найти похожие

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Jia, Bin, Huang, Lujun, Pilipchuk A. S., Huang, Sibo, Shen, Chen, Sadreev A. F., Li, Yong, Miroshnichenko, Andrey E.
Заглавие : Bound states in the continuum protected by reduced symmetry of three-dimensional open acoustic resonators
Место публикации : Phys. Rev. Appl. - 2023. - Vol. 19, Is. 5. - Ст.054001. - ISSN 23317019 (eISSN), DOI 10.1103/PhysRevApplied.19.054001
Примечания : Cited References: 30. - L. Huang and A.E. Miroshnichenko were supported by the Australian Research Council Discovery Project (DP200101353) and the UNSW Scientia Fellowship program. B. Jia, S. Huang, and Y. Li are supported by the National Natural Science Foundation of China (Grant No. 12074286), and Shanghai Science and Technology Committee under Grant No. 21JC1405600
Аннотация: Bound states in the continuum (BICs) have been demonstrated as a powerful tool for trapping acoustic fields in an acoustic resonator. It has been widely recognized that symmetry-protected (SP) BICs result from symmetry incompatibility of some eigenmodes of a resonator with propagating modes of waveguides. The most typical example of SP BIC is the odd eigenmode of the resonator with the eigenfrequency embedded into the propagating band of even propagating eigenmodes of the waveguide. In this work, we consider a more sophisticated case of an acoustic cuboid resonator that is opened by the attachment of two cylindrical waveguides. We show that BICs can be sustained in an open acoustic resonator with reduced symmetry. For symmetrical positions of waveguides, the eigenmodes of the cuboid can also be classified as SP BICs and show different stability against the shifts of waveguides from the positions of symmetry of the cuboid. We fabricate a series of coupled waveguide resonators and experimentally verify the existence of these BICs by identifying the vanished linewidth of Fano resonance in transmission spectra. Besides, we also show that evanescent modes of waveguides play a role in the formation of BICs in a nonaxisymmetric waveguide-resonator system by tuning the angle θ between two waveguides. Consequently, the eigenmodes remain SP BICs for θ = 0° and θ = 180° but convert into accidental BICs at θ ≈ 85° or θ ≈ 275°. Such accidental BICs are also experimentally verified. Our results enrich the understanding of SP BICs and accidental BICs, and provide alternative methods of routing acoustic waves and designing acoustic devices requiring fine spectrum features, such as filters and sensors.
Смотреть статью,
Читать в сети ИФ
Найти похожие

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Enkova, Eugenia O., Stepanenko, Vitaly A., Shustin M. S.
Заглавие : Symmetry analysis of radial profiles of magnetic skyrmions
Колич.характеристики :9 с
Место публикации : J. Sib. Fed. Univ. Math. Phys. - 2023. - Vol. 16, Is. 6. - P.811-819. - ISSN 19971397 (ISSN); Журн. СФУ. Матем. и физ. - ISSN 23136022 (eISSN)
Примечания : Cited References: 16. - S.M.S. thanks Maria Potkina as the author of magnetic skyrmionium ansantz, for fruitful discussions and her enormous contribution to this work. The authors thank D. M. Dzebisashvili for useful discussions. The work was carried out within the state assignment of Kirensky Institute of Physics. The work was supported by the Foundation for the Development of Theoretical Physics and Mathematics "BASIS" (project no. 23-1-3-52-1), Krasnoyarsk Mathematical Center of the Ministry of Science and Higher Education of the Russian Federation, Agreement no. 75-02-2023-936
Аннотация: The search for analytical profiles of chiral magnetic structures such as 2D magnetic skyrmions (MS) is important for their theoretical study. Since the Euler–Lagrange (EL) equations for such excita- tions are not solved exactly, the MSs are described using analytical ansatzs. In this work, we validate one of the widely used ansatzs based on a symmetry analysis of the 1D analog of the EL equations, which characterizes the radial profile of the MS. As a development of this approach, a profiles of skyrmion bags are proposed.Поиск аналитических профилей киральных магнитных структур типа 2D магнитных скирмионов (МС) является важным при их теоретическом описании. Поскольку уравнения Эйлера–Лагранжа (ЭЛ) для таких возбуждений не решаются точно, описание МС проводят с помощью аналитических пробных функций — анзацев. В настоящей работе проводится обоснование одного из широко используемых анзацей на основе симметрийного анализа 1D версии уравнений ЭЛ, определяющего радиальный профиль МС. В развитии такого подхода предлагаются профили скирмионных мешков с топологическими зарядами Q ≥ 0.
Смотреть статью,
РИНЦ,
Scopus
Найти похожие

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Shadrina G. V., Bulgakov E. N.
Заглавие : Optical bistability and symmetry breaking at resonance scattering of light by a finite photonic crystal with a nonlinear resonant cavity
Место публикации : J. Exp. Theor. Phys. - 2022. - Vol. 135, Is. 5. - P.632-641. - ISSN 10637761 (ISSN), DOI 10.1134/S1063776122110176. - ISSN 10906509 (eISSN)
Примечания : Cited References: 50. - This study was supported by the Russian Science Foundation, grant no. 22-12-00070
Аннотация: Optical bistability and symmetry breaking under the conditions of plane wave incidence on a system of coupled photonic crystal microcavities containing an inclusion with Kerr susceptibility have been studied. The T-matrix modal method has been generalized for the case of nonlinear microcavities supporting one monopole mode. It has been shown that both phenomena considerably depend not only on external field strength but also on angle of incidence and photonic crystal size.
Смотреть статью,
WOS
Найти похожие

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Fedchenko, Dmitry P., Kim, Petr N., Timofeev I. V.
Заглавие : Photonic topological insulator based on frustrated total internal reflection in array of coupled prism resonators
Место публикации : Symmetry. - 2022. - Vol. 14, Is. 12. - Ст.2673. - ISSN 20738994 (eISSN), DOI 10.3390/sym14122673
Примечания : Cited References: 19
Аннотация: Total internal reflection occurs at the interface between two media with different refractive indices during propagation of light rays from a medium with a higher refractive index to a medium with a lower refractive index. If the thickness of the second medium is comparable to a specific light wavelength, then total internal reflection is violated partially or completely. Based on the frustrated total internal reflection, herein we discuss a two-dimensional photonic topological insulator in an array consisting of triangular, quadrangular, or hexagonal transparent prism resonators with a narrow gap between them. An array of prism resonators allows topologically stable edge solutions (eigenwaves) similar to those studied in ring resonators. Moreover, total internal reflection occurs at different angles of incidence of light. This makes it possible to obtain a set of fundamentally new edge solutions. The light is presumably concentrated at the surface; however, in the new solutions it penetrates relatively deep into the photonic topological insulator and excites several layers of prisms positioned beyond the surface. Remarkably, the direction of light propagation is precisely biased, and therefore new solutions exhibit lower symmetry than the resonator array symmetry.
Смотреть статью,
WOS,
Читать в сети ИФ
Найти похожие

Вид документа : Однотомное издание
Шифр издания :
Автор(ы) : Loiko V. A., Konkolovich A. V., Miskevich A. A., Krakhalev M. N., Prishchepa O. O., Shabanov A. V., Zyryanov V. Ya.
Заглавие : Electro-optical response of a monolayer polymer dispersed nematic liquid crystal film doped with surfactant
Место публикации : Liquid Crystal Polymer Nanocomposites: Woodhead Publishing, 2022. - Chapter 7. - P.163-211. - , DOI 10.1016/B978-0-12-822128-0.00006-6
Примечания : Cited References: 86
Аннотация: Light scattering and transmission by a monolayer polymer dispersed liquid crystal film containing liquid crystal droplets with inhomogeneous anchoring of liquid crystal molecules at the polymer-droplet interface is considered theoretically and experimentally. The developed optical model is based on the anomalous diffraction and interference approximations of the theory of scattering of waves. It is applied to describe the interference quenching effect for the coherently transmitted light and electrically controllable symmetry breaking effect in small-angle structure of light scattered by film containing droplets with inhomogeneous anchoring. The analysis of transmittance and reflectance of the one-dimensional photonic crystals composed of monolayers is carried out. The formation of the photonic band gaps is analyzed.
Смотреть главу,
Scopus
Найти похожие

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Tomilin F. N., Pomogaev V. A., Melchakova Y. A., Artyushenko P. V., Shubin A. A., Volodin A. M., Zilberberg I. L., Avramov P. V.
Заглавие : Structure and properties of exotic nano- and mesodiamonds with pentagonal symmetry
Место публикации : Russ. Phys. J. - 2022. - Vol. 64, Is. 11. - P.2046-2051. - ISSN 10648887 (ISSN), DOI 10.1007/s11182-022-02553-0
Примечания : Cited References: 16. - These results were obtained within the framework of the State Assignment of the Russian Ministry of Education and Science (No. 0721-2020-0033)
Аннотация: A comprehensive critical survey of structures of exotic nano-, meso- and microdiamonds with dodecahedral and icosahedral symmetry (N/MDPS) is presented. Due to their high dodecahedral or icosahedral symmetry, the unique complex atomic and electronic structure of N/MDPS leads to transport and mechanical properties very promising for photonic, quantum, and nanomechanical applications. To explain the nature of diamonds, theoretical models have been proposed based on the formation of twinned structures consisting of either 5 or 20 symmetrically equivalent tetrahedral and prismatic fragments of the face-centered cubic lattice with the formation of star-shaped or icosahedral clusters, respectively. It has been shown that these twinned nano- and mesodiamonds have limited dimensions due to accumulation of uncompensated structural stresses arising from the deviation of the angles between diamond 111 facets from perfect 72° in tetrahedral fragments of the face-centered cubic lattice to 70.5° between five symmetrically equivalent twinned fragments.
Смотреть статью,
Scopus
Найти похожие

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Makarov I. A., Ovchinnikov S. G.
Заглавие : Enhanced s*-wave component of the superconducting gap in overdoped HTSC cuprates with orthorhombic distortion
Место публикации : Phys. Lett. A. - 2022. - Vol. 444. - Ст.128226. - ISSN 03759601 (ISSN), DOI 10.1016/j.physleta.2022.128226
Примечания : Cited References: 67. - We would like to especially thank A. Bianconi for new ideas, useful discussions, and suggestions. The reported study was funded by Russian Foundation for Basic Research, Government of Krasnoyarsk Territory and Krasnoyarsk Regional Fund of Science according to the research project “Studies of superexchange and electron-phonon interactions in correlated systems as a basis for searching for promising functional materials” No. 20-42-240016
Аннотация: In this work, the concentration and temperature dependence of the superconducting gap of the HTSC cuprate in the orthorhombic phase are obtained within the framework of the Hubbard model taking into account the exchange mechanism of pairing. To elucidate the reasons for the unexpectedly large s*-wave component of the superconducting gap in the overdoped regime, the electronic structure of low-energy excitations and the k-dependent contributions of pair states to the gap components were investigated. It is shown that the s*-wave component growth results from the shallowing of the electron pocket in the region of the s*-wave component maximum.
Смотреть статью,
Scopus,
Читать в сети ИФ
Найти похожие

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Moshkina E. M., Krylov A. S., Kokh D., Shabanova K., Molokeev M. S., Bovina A. F., Plyaskin M., Rostovtsev N., Bezmaternykh L. N.
Заглавие : Multicomponent flux growth and composition control of Cu2MnBO5:Ga ludwigites
Место публикации : CrystEngComm. - 2022. - Vol. 24, Is. 19. - P.3565-3575. - ISSN 14668033 (ISSN), DOI 10.1039/d2ce00258b
Примечания : Cited References: 26. - This study was supported by the Russian Science Foundation (Grant No. 21-72-00130). The Raman, X-ray, and EDX data were obtained using the analytical equipment of the Krasnoyarsk Regional Center of Research Equipment of the Federal Research Center “Krasnoyarsk Science Center SB RAS”
Аннотация: To reach the concentration phase boundary between antiferromagnetic Cu2GaBO5 and ferrimagnetic Cu2MnBO5 ludwigites, solid solutions Cu2Mn1−xGaxBO5 (x = 0.05, 0.1, 0.15, 0.175) were grown by the flux technique using a multi-component solvent based on Bi2Mo3O12 with the addition of Na2B4O7 which significantly influenced the crystal formation and cation composition of the studied compounds. The content of the flux system was corrected taking into account the earlier established relationship of the partition coefficients of Mn2O3 and Ga2O3. The influence of the solvent components on the ludwigite crystallization was analyzed. The maximum size of the grown crystal was 1 × 1 × 4 mm3. The structure and cation composition of the grown compounds were studied using X-ray (X-ray diffraction, EDX (energy-dispersive X-ray spectroscopy)) and vibrational (Raman) spectroscopy techniques. The phase boundary of Cu2MnBO5–Cu2GaBO5 was found to be in the concentration range of x = 0.15–0.175, corresponding to a change in the monoclinic axis direction and a leap in the lattice parameters. The symmetry evolution of metal–oxygen octahedra for four nonequivalent cation positions was analyzed, and the unique crystal structure of Cu2MnBO5 demonstrated high rigidity relative to the introduction of Ga3+ cations. The polarized Raman spectra of monoclinic ludwigites were obtained and studied for the first time. A comparison of the spectra of the studied samples in both phases and orthorhombic ludwigites was made. A number of spectral features due to the monoclinic distortions in the crystal were found. In agreement with the Raman experiment, the concentration phase boundary was close to 0.15.
Смотреть статью,
Scopus
Найти похожие

10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Sorensen L. K., Utyushev A. D., Zakomirnyi V. I., Gerasimov V. S., Ershov A. E., Polyutov S. P., Karpov S. V., Agren H.
Заглавие : Plasmonic enhancement of local fields in ultrafine metal nanoparticles
Место публикации : J. Phys. Chem. C. - 2021. - Vol. 125, Is. 5. - P.13900-13908. - ISSN 19327447 (ISSN), DOI 10.1021/acs.jpcc.1c01424
Примечания : Cited References: 65. - The work was supported by the Russian Science Foundation (project no. 18-13-00363). L.K.S acknowledges the support of Carl Tryggers Stifetelse, project CTS 18-441
Аннотация: We present an analysis of ultrafine metallic nanoparticles (1-15 nm) with respect to electromagnetic field generation by plasmonic excitations. A number of structures with different symmetries and geometries are studied in order to analyze the distributions of plasmonically generated near-electric fields and the concentration of hot and cold spots around the particles. The study is made possible by the recent development of an extended discrete interaction model (Ex-DIM) where the explicit dependency of the plasmonic spectra on the structure and composition of particles in the range of 1-15 nm is accounted for. With the Ex-DIM, the optical response of the internal crystal structure of the nanoscale particles can be visualized, thereby making it possible to predict the dependence of the generated local fields with respect to the position of the particles relative to the external field polarization. The results indicate rather surprising concentrations of the plasmon fields in very confined hot spots also in cases when the particles retain a high symmetry. The consequence of the findings of this study when using small symmetric nanoparticles for near-field imaging is briefly discussed.
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kveglis, Ludmila I., Noskov, Fedor M., Volochaev M. N., Nyavro, Alexander V., Filarowski, Aleksander
Заглавие : Magnetic properties of nickel-titanium alloy during martensitic transformations under plastic and elastic deformation
Место публикации : Symmetry. - 2021. - Vol. 13, Is. 4. - Ст.665. - ISSN 2073-8994(eISSN), DOI 10.3390/sym13040665
Примечания : Cited References: 61
Предметные рубрики: NITI SHAPE-MEMORY
CRYSTAL-STRUCTURE
WAVE MECHANICS
TRANSITIONS
Аннотация: This paper focuses on the processes of the occurrence of magnetization during structure formation in samples of Ni51Ti49 alloy under deformation conditions. The possibility of the existence of a phase with an FCC (face-centered cubic) lattice in titanium nickelide has been demonstrated by electron microscopy and electron diffraction. It has been discovered that the interplanar distances of BCC110 (body-centered cubic), FCC111, and HCP002 (hexagonal close packed) in the alloy under study have similar values, which indicates the possibility of their mutual polymorphic transformation. Based on the modular self-organization, a scheme of martensitic transformations in titanium nickelide from the B2 structure (BCC lattice) to the B19' structure (HCP lattice) through an intermediate phase with an FCC lattice is proposed. It is shown that lenticular crystals appear in the Ni51Ti49 alloy under tensile deformation until rupture, which is accompanied by the onset of ferromagnetism. The effect of magnetization in Ni51Ti49 samples when immersed in liquid nitrogen has been also discovered. In this case, the reason for the appearance and disappearance of magnetization can be associated with microdeformation processes caused by direct and reverse martensitic transitions that occur during cooling and heating of the samples.
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ekholm V., Chiuzbaian G. S., Sathe C., Nicolaou A., Guarise M., Simon M., Jaouen N., Luning J., Hague C. F., Gel'mukhanov F., Odelius M., Bjorneholm O., Rubensson, J-E
Заглавие : Core-hole localization and ultra-fast dissociation in SF6
Коллективы : Swedish Research Council (VR)Swedish Research Council; Russian Science FoundationRussian Science Foundation (RSF) [16-12-10109]
Место публикации : J. Phys. B. - 2020. - Vol. 53, Is. 18. - Ст.185101. - ISSN 0953-4075, DOI 10.1088/1361-6455/aba204. - ISSN 1361-6455(eISSN)
Примечания : Cited References: 36. - This work was supported by the Swedish Research Council (VR). The calculations were performed on resources provided by the Swedish National Infrastructure for Computing (SNIC). FG acknowledges support within the Russian Science Foundation (Project No. 16-12-10109)
Предметные рубрики: X-RAY-EMISSION
SYMMETRY-BREAKING
AB-INITIO
SPECTROSCOPY
SPECTRA
Аннотация: Resonant inelastic x-ray scattering spectra excited at the fluorine K resonances of SF6 have been recorded. While a small but significant propensity for electronically parity-allowed transitions is found, the observation of parity-forbidden electronic transitions is attributed to vibronic coupling that breaks the global inversion symmetry of the electronic wavefunction and localizes the core hole. The dependence of the scattering cross section on the polarization of the incident radiation and the scattering angle is interpreted in terms of local π/σ symmetry around the S–F bond. This symmetry selectivity prevails during the dissociation that occurs during the scattering process.
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Bychek A. A., Maksimov D. N., Kolovsky A. R.
Заглавие : Decay of symmetry-protected quantum states
Коллективы : Russian Science FoundationRussian Science Foundation (RSF) [N19-12-00167]
Место публикации : Phys. Rev. A. - 2020. - Vol. 102, Is. 3. - Ст.033324. - ISSN 2469-9926, DOI 10.1103/PhysRevA.102.033324. - ISSN 2469-9934(eISSN)
Примечания : Cited References: 47. - This work has been supported by Russian Science Foundation through Grant No. N19-12-00167. We appreciate discussions with A. F. Sadreev and E. N. Bulgakov. We are also grateful to G. P. Fedorov for his critical reading of the manuscript
Предметные рубрики: DRIVEN
Аннотация: We study the decay of bosonic many-body states in the triple-well Bose-Hubbard model where bosons in the central well can escape into a reservoir. For vanishing interparticle interaction this system supports a nondecaying many-body state which is the antisymmetric Bose-Einstein condensate with particles occupying only the edge wells. In the classical approach this quantum state corresponds to a symmetry-protected nondecaying state which is stable even at finite interaction below a certain intensity threshold. Here we demonstrate that despite the fact that the classical counterpart is stable the antisymmetric Bose-Einstein condensate is always metastable at finite interatomic interactions due to quantum fluctuations.
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Pichugin K. N., Puente A., Nazmitdinov R.
Заглавие : Kramers Degeneracy and Spin Inversion in a Lateral Quantum Dot
Место публикации : Symmetry. - 2020. - Vol. 12, Is. 12. - Ст.2043. - ISSN 2073-8994, DOI 10.3390/sym12122043
Примечания : Cited References: 46
Аннотация: We show that the axial symmetry of the Bychkov–Rashba interaction can be exploited to produce electron spin-flip in a circular quantum dot, without lifting the time reversal symmetry. In order to elucidate this effect, we consider ballistic electron transmission through a two-dimensional circular billiard coupled to two one-dimensional electrodes. Using the tight-binding approximation, we derive the scattering matrix and the effective Hamiltonian for the considered system. Within this approach, we found the conditions for the optimal realization of this effect in the transport properties of the quantum dot. Numerical analysis of the system, extended to the case of two-dimensional electrodes, confirms our findings. The relatively strong quantization of the quantum dot can make this effect robust against the temperature effects.
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Sadrieva Z. F., Belyakov M. A., Balezin M. A., Kapitanova P. V., Nenasheva E. A., Sadreev A. F., Bogdanov A. A.
Заглавие : Experimental observation of a symmetry-protected bound state in the continuum in a chain of dielectric disks
Коллективы : Russian Science Foundation [17-12-01581]; RFBR [18-32-20205]; Ministry of Education and Science of the Russian Federation [3.1668.2017/4.6]; Foundation for the Advancement of Theoretical Physics and Mathematics "BASIS"
Место публикации : Phys. Rev. A. - 2019. - Vol. 99, Is. 5. - Ст.053804. - ISSN 2469-9926, DOI 10.1103/PhysRevA.99.053804. - ISSN 2469-9934(eISSN)
Примечания : Cited References:61. - The numerical simulations and experimental part of this work were supported by the Russian Science Foundation (Grant No. 17-12-01581), and the analytical calculations were supported by RFBR (Grant No. 18-32-20205) and the Ministry of Education and Science of the Russian Federation (3.1668.2017/4.6). The authors are thankful to Andrey Sayanskiy for assistance in the holder fabrication. A.A.B. and Z.F.S. acknowledge the Foundation for the Advancement of Theoretical Physics and Mathematics "BASIS" for valuable financial support.
Предметные рубрики: LIGHT
RESONANCES
RADIATION
MOMENTUM
BEHAVIOR
LAYER
Аннотация: The existence of bound states in the continuum (BIC) manifests a general wave phenomenon first predicted in quantum mechanics by John von Neumann and Eugene Wigner [J. von Neumann and E. Wigner, Phys. Z. 30, 465 (1929)]. Today it is being actively explored in photonics, radiophysics, acoustics, and hydrodynamics. We report an experimental observation of an electromagnetic bound state in the radiation continuum in a one-dimensional array of dielectric particles. By measurement of the transmission spectra of the ceramic disk chain at GHz frequencies, we demonstrate how a resonant state in the vicinity of the center of the Brillouin zone turns into a symmetry-protected BIC with increase in the number of the disks. We estimate a number of the disks when the radiation losses become negligible in comparison to material absorption and, therefore, the chain could be considered practically as infinite. The presented analysis is supplemented by measurements of the near fields of the symmetry-protected BIC. All measurements are in a good agreement with the results of the numerical simulation and analytical model based on a tight-binding approximation. The obtained results provide useful guidelines for practical implementations of structures with bound states in the continuum that opens up horizons for the development of optical and radio-frequency metadevices.
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Wei Y., Qu X., Li G., Cheng Z., Molokeev M. S., Lin C. C., Chan T. -S., Chang C. -K., Chuang Y. -C., Lin J.
Заглавие : Ultra-narrow band blue emission of Eu2+ in halogenated (Alumino)borate systems based on high lattice symmetry
Место публикации : J. Am. Ceram. Soc. - 2019. - Vol. 102. - P.2353– 2369. - ISSN 00027820 (ISSN) , DOI 10.1111/jace.16127
Примечания : Cited References: 63. - This work was supported by the National Natural Science Foundation of China (Grant Nos. 51672259, 51672265, 21521092, 51750110511), Engineering Research Center of Nano-Geomaterials of Ministry of Education, China University of Geosciences (Wuhan) (No. NGM2016KF002), the Ministry of Science and Technology of Taiwan (Contract No. MOST 104-2113-M-027-007-MY3), the Key Research Program of Frontier Sciences, CAS (Grant No. YZDY-SSW-JSC018), and projects for science and technology development plan of Jilin province (20170414003GH), the Program for Jiangmen Innovative Reasearch Team (No.[2017]385),major program of basic research and applied research of Guangdong Province (2017KZDXM083) and the Russian Science Foundation (Grant No. 17-12-01047).
Ключевые слова (''Своб.индексиров.''): blue emission--high symmetry--phosphors--ultra-narrow band--wleds
Аннотация: Phosphor materials with ultra‐high color purity are highly desired in backlit display and WLEDs. How to achieve high‐purity three‐primary emission in rare earth ions activated inorganic phosphors has become a hot topic. Herein, we reported ultra‐narrow band and highly efficient blue‐violet‐emitting Eu2+‐doped Ba2B5O9X (fwhm = 31 nm) and NaBa4(AlB4O9)2X3 (X = Cl, Br) (fwhm = 43 nm) phosphors with peak positions around 424‐437 nm. Especially, the color purity of Ba2B5O9Cl:Eu sample even exceeded 97%, its internal quantum efficiency could achieve 87%. The EXANES analysis revealed that the Eu mainly existed in the form of +2. According to the Rietveld structural refinement, extraordinarily narrow band emission should be attributed to the highly symmetric lattice structures with the flower‐like polyhedrons in the studied (alumino)borate matrix. Significantly, the color gamut of as‐prepared blue phosphor combined with the standard green and red phosphors was almost close to that of Rec. 2020 display standard. In addition, cation substitution strategy in NaBa4(AlxB5‐xO9)2Cl3 (x = 0‐4) and NaBa4(GayB5‐yO9)2Cl3 (y = 0‐3) samples successfully achieved spectra adjustment, and the underlying mechanism was proposed. All these results demonstrate that the as‐prepared phosphors could be superior blue‐emitting candidates for backlit display as well as WLEDs.
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Dzebisashvili D. M., Klyuchantsev, Andrey B.
Заглавие : London Penetration Depth as a Test of Order Parameter Symmetry in Sodium Cobaltate Superconductors
Коллективы : Russian Foundation for Basic Research (RFBR) [18-02-00837]; Presidium of the Russian Academy of Sciences [12]
Место публикации : Symmetry-Basel. - 2019. - Vol. 11, Is. 5. - Ст.633. - ISSN 2073-8994, DOI 10.3390/sym11050633
Примечания : Cited References: 43. - The work was financially supported by the Russian Foundation for Basic Research (RFBR) (project no. 18-02-00837) and by the program of the Presidium of the Russian Academy of Sciences No. 12 "Fundamental problems of high-temperature superconductivity".
Предметные рубрики: SPIN
DEPENDENCE
POWDER
CHARGE
PHASE
GAP
Аннотация: Temperature dependence of the magnetic field penetration depth λ was calculated for water intercalated sodium cobaltate superconductor NaxCoO2⋅yH2O. Assuming that the system is in the chiral d+id–wave superconducting state, it was shown that the shifting of the excitation spectrum nodal points off the normal phase Fermi surface due to variation of the sodium content x changes the functional form of the temperature dependence of λ−2 from exponential to linear in the low temperatures region. It is argued that this change in the functional form of T–dependence of the λ−2 can serve as a proof for the chiral symmetry of the superconducting order parameter in the sodium cobaltate.
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gavrichkov V. A., Shan'ko, Yury, Zamkova N. G., Bianconi A.
Заглавие : Is There Any Hidden Symmetry in the Stripe Structure of Perovskite High-Temperature Superconductors?
Коллективы : RFBR [18-42-240017]; Government of the Krasnoyarsk Region [18-42-240017]; Krasnoyarsk Regional Fund of Science [18-42-240017]
Место публикации : J. Phys. Chem. Lett. - 2019. - Vol. 10, Is. 8. - P.1840-1844. - ISSN 1948-7185, DOI 10.1021/acs.jpclett.9b00513
Примечания : Cited References: 68. - One of the authors (V.A.G.) is grateful to RFBR, the Government of the Krasnoyarsk Region and Krasnoyarsk Regional Fund of Science for the research Grant No. 18-42-240017
Предметные рубрики: T-C
CUO2 PLANE
INHOMOGENEOUS SUPERCONDUCTIVITY
PHASE-DIAGRAM
Аннотация: Local and fast structural probes using synchrotron radiation have shown nanoscale striped puddles and nanoscale phase separation in doped perovskites. It is known that the striped phases in doped perovskites are due to competing interactions involving charge, spin, and lattice degrees of freedom. In this work, we show that two different stripes can be represented as a superposition of a pair of stripes, U(θn) or D(θn), characterized by perovskite tilts where one of the pair is rotated in relation to the other partner by an angle Δθn = π/2. The spatial distribution of the U and D stripes is reduced to all possible maps in the well-known mathematical four-color theorem. Both the periodic striped puddles and random structures can be represented by using planar graphs with a chromatic number χ ≤ 4. To observe the colors in mapping experiments, it is necessary to recover variously oriented tilting effects from the replica. It is established that there is an interplay between the annihilation/creation of new stripes and ordering/disordering tilts in relation to the θn angle in the CuO2 plane, where the characteristic shape of the stripes coincides with the tilting-ordered regions.
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Xing G., Feng Y., Pan M., Wei Y., Li G., Dang P., Liang S., Molokeev M. S., Cheng Z., Lin J.
Заглавие : Photoluminescence tuning in a novel Bi3+/Mn4+ co-doped La2ATiO6:(A = Mg, Zn) double perovskite structure: Phase transition and energy transfer
Место публикации : J. Mater. Chem. C. - 2018. - Vol. 6, Is. 48. - P.13136-13147. - ISSN 20507534 (ISSN), DOI 10.1039/c8tc05171b
Примечания : Cited References: 60. - This work was supported by the National Natural Science Foundation of China (Grant No. 51672259, 51672265, 21521092, 51750110511), the Engineering Research Center of Nano-Geomaterials of Ministry of Education, China University of Geosciences (Wuhan) (No. NGM2016KF002), the Key Research Program of Frontier Sciences, CAS (Grant No. YZDYSSW-JSC018), and the projects for science and technology development plan of Jilin province (20170414003GH), the Program for Jiangmen Innovative Research Team (No. [2017]385), and the major program of basic research and applied research of Guangdong Province (2017KZDXM083).
Ключевые слова (''Своб.индексиров.''): crystal symmetry--energy transfer--light--luminescence--perovskite--phosphors--rietveld refinement
Аннотация: Red-emitting phosphors are indispensable compounds which are used to achieve a warm white light in phosphor-converted white light emitting diodes (pc-WLEDs). However, the luminous efficiency and stability of red phosphors are still big challenges. In this work, we developed red-emitting double perovskite phosphors La2ATiO6:Bi3+,Mn4+ (A = Mg, Zn) (LAT:Bi3+,Mn4+) and discuss the relationship between the double perovskite phosphor structure and the luminescence performance in detail. According to the Rietveld refinement results for the La2Mg(1−w)ZnwTiO6:Bi3+,Mn4+ (0 ≤ w ≤ 1) (LM(1−w)ZwT:Bi3+,Mn4+) solid solution, the proposed mechanism of the spectral adjustment is ascribed to the appearance of the phase transition, which results in a lower local structural symmetry of the [LaO12] polyhedron and the variation of the crystal field environment for Mn4+. Notably, this is the first time that the influence of the local structure variation on the luminescence tuning in double perovskite structure phosphors has been revealed, and this could offer guidance for the development of new phosphor system. By designing Mg2+/Zn2+ cation substitution, the internal quantum efficiency (IQE) is remarkably enhanced beyond 20%. In addition, we succeeded in achieving a Bi3+/Mn4+ co-doped energy transfer in the double perovskite structure phosphors. Owing to the Bi3+ → Mn4+ energy transfer in LAT, the red emission of the Mn4+ ions could be dramatically enhanced. The energy transfer efficiency of LAT:Bi3+,Mn4+ eventually exceeded 90%. The IQE and the thermal stability were all enhanced by around 30% compared to the non-co-doped samples, respectively. These results indicate that the Bi3+ → Mn4+ energy transfer strategy could play a pivotal role in the development of highly efficient red-emitting phosphors. The performance of the fabricated pc-WLEDs devices indicates that LAT:Bi3+,Mn4+ could be a promising red phosphor for near ultraviolet (n-UV) based warm pc-WLEDs.
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Malakhovskii A. V., Sokolov V. V., Gudim I. A.
Заглавие : Influence of the low local symmetry of Er3+ ions on magnetic circular dichroism and absorption spectra of f-f transitions in ErFe3(BO3)4 single crystal
Место публикации : J. Magn. Magn. Mater. - 2018. - Vol. 465. - P.700-708. - ISSN 03048853 (ISSN), DOI 10.1016/j.jmmm.2018.06.057
Примечания : Cited References: 29. - The work was supported by the Russian Foundation for Basic Researches grant 16-02-00273 and by the Project of Russian Academy of Science No. 0356-2017-0030.
Ключевые слова (''Своб.индексиров.''): er3+ ion--f-f transitions--magnetic circular dichroism--rare earth ferroborates
Аннотация: Linearly polarized absorption spectra and magnetic circular dichroism (MCD) spectra of ErFe3(BO3)4 single crystal were measured in the range of 9000–23000 cm−1 at 90 K. The absorption spectra of f-f transitions were decomposed into the Lorentz shape components and intensities of the components were found. MCD spectra permitted us to measure the Zeeman splitting of some transitions and so to determine changes of the Landé factor along the C3 axis of the crystal during these transitions. Optical and magneto-optical properties of f-f transitions in the ErFe3(BO3)4 crystal were compared with those in the ErAl3(BO3)4 crystal. Substantial difference of the properties connected with the difference of the Er3+ ions local symmetry in two crystals was revealed. Large splitting of one of the f-f transitions without magnetic field, which is not possible for the Kramers doublets, was observed. It was explained by appearance of two absorbing centers due to the local decrease of symmetry in the excited state. Appreciable difference of the local vibrations energy in some excited states was revealed.
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие