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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Fransson J., Sandalov I., Eriksson O.
Заглавие : A perfect spin-filter quantum dot system
Место публикации : J. Phys.: Condens. Matter: IOP PUBLISHING LTD, 2004. - Vol. 16, Is. 16. - P.L249-L254. - ISSN 0953-8984, DOI 10.1088/0953-8984/16/16/L03
Примечания : Cited References: 39
Предметные рубрики: NARROW ENERGY BANDS
ELECTRON CORRELATIONS
MAGNETIC-FIELD
MAGNETOTRANSPORT
CONDUCTANCE
RESISTANCE
BARRIER
FORMULA
VALVE
LIMIT
Ключевые слова (''Своб.индексиров.''): electric potential--electron tunneling--magnetic couplings--magnetic fields--magnetic filters--transport properties--electron correlations--magnetic contacts--source-drain voltage--spin projections--semiconductor quantum dots
Аннотация: The discovery of a novel effect in the transport through a QD spin-dependently coupled to magnetic contacts is reported. For a finite range of source-drain voltages the spin projections of the current cancel exactly, resulting in a completely suppressed output current. The spin down current behaves as one normally expects whereas the spin up current becomes negative. As the source-drain voltage is increased the spin up current eventually becomes positive. Thus, tuning the source-drain voltage such that the spin up current vanishes will result in a perfect spin filter.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Smolyakov D. A., Tarasov A. S., Bondarev M. A., Nikolskaya A. A., Vasiliev V. K., Volochaev M. N., Volkov N. V.
Заглавие : Admittance spectroscopy of dopants implanted in silicon and impurity state-induced AC magnetoresistance effect
Место публикации : Mater. Sci. Semicond. Process. - 2021. - Vol. 126. - Ст.105663. - ISSN 13698001 (ISSN), DOI 10.1016/j.mssp.2021.105663
Примечания : Cited References: 21. - This study was supported by the Government of the Russian Federation , Mega Grant for the Creation of Competitive World-Class Laboratories (Agreement no. 075-15-2019-1886)
Аннотация: A silicon structure doped with Ga using ion implantation has been investigated by admittance spectroscopy. It has been established that the presence of the Ga impurity, along with the B one, in the silicon structure leads to the appearance of the second peak in the temperature dependence of the real part of the impedance (admittance). Moreover, switching-on a magnetic field parallel to the sample plane shifts the singularities in the temperature curve to the high-temperature region. This results in the manifestation of both the positive and negative magnetoresistance effect upon temperature and magnetic field variation. It has been found by the standard admittance spectroscopy analysis of the impedance data that the energy structure of the investigated sample includes two interfacial energy levels ES1(0) = 42 meV and ES2(0) = 69.4 meV. As expected, these energies are consistent with the energies of B and Ga dopants. In a magnetic field, these levels increase by 3 meV for B and 2 meV for Ga, which induces the magnetoresistance effect. It has been demonstrated that the interfacial state-induced magnetoresistance effect can be tuned by ion implantation and dopant selection.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Hu T., Molokeev M. S., Xia Z., Zhang Q.
Заглавие : Aliovalent substitution toward reinforced structural rigidity in Ce3+-doped garnet phosphors featuring improved performance
Место публикации : J. Mater. Chem. C. - 2019. - Vol. 7, Is. 46. - P.14594-14600. - ISSN 20507534 (ISSN), DOI 10.1039/c9tc05354a
Примечания : Cited References: 38. - This work was supported by the National Natural Science Foundation of China (No. 51722202 and 51972118), the Guangdong Provincial Science & Technology Project (2018A050506004) and the Fundamental Research Funds for the Central Universities (D2190980).
Аннотация: Highly efficient phosphors with thermal stability and color-tunable emission are required for the fabrication of phosphor-converted white light-emitting diodes (pc-WLEDs). Currently developed engineering strategies are generally successful in photoluminescence tuning but, unfortunately, suffer severe deterioration in emission intensity/efficiency and/or thermal stability. Herein, an efficient aliovalent substitution strategy toward reinforced structural rigidity is proposed and demonstrated experimentally. By incorporating Be2+ ion into the garnet-type Lu2SrAl4SiO12:Ce3+ phosphor, the phosphor shows enhanced internal/external quantum efficiency, from 79.2%/26.7% to 84.5%/32.9%, photoluminescence tuning from green (peaking at ∼512 nm) to yellow (peaking at ∼552 nm), and zero thermal quenching, even up to 200 °C. The Be2+ substitution at the Al2/Si2 site enables stable and rigid local surroundings around the Ce3+ activator, which is responsible for the unprecedented performance. In addition, high-quality warm WLED devices with a luminous efficiency of 158.1 lm W-1, correlated color temperature of 3858 K and high color rendering index of 81.7, are obtained by combining Lu2SrAl4SiO12:Ce3+,Be2+ as the yellow emitter, CaAlSiN3:Eu2+ as the red emitter and a blue-emitting InGaN chip. These findings highlight a new strategy for performance optimization of LED phosphors by selecting rigid covalent compounds with further reinforced structural rigidity via aliovalent substitution.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Fedorov D.G., Kitaura K., Avramov P. V., Jensen J.H.
Заглавие : Analytic gradient for the adaptive frozen orbital bond detachment in the fragment molecular orbital method
Место публикации : Chem. Phys. Lett. - 2009. - Vol. 477, Is. 1-3. - P.169-175. - JUL 28. - ISSN 0009-2614, DOI 10.1016/j.cplett.2009.06.072
Примечания : Cited Reference Count: 49. - Гранты: We thank Professor M. Suenaga of Kyushu University for continuing his development of the modeling software FACIO and its FMO interface. D. G. F. and K. K. were supported by the a Grant-in- Aid for Scientific Research (JSPS, Japan) and the Next Generation SuperComputing Project, Nanoscience Program (MEXT, Japan). J.H.J. was supported by a Skou Fellowship from the Danish Research Agency (Forskningsradet for Natur og Univers).Финансирующая организация: JSPS, Japan; Next Generation SuperComputing Project; MEXT, Japan; Danish Research Agency
Предметные рубрики: DENSITY-FUNCTIONAL THEORY
GEOMETRY OPTIMIZATIONS
SEMICONDUCTOR NANOWIRES
SILICON NANOWIRES
METHOD FMO
ENERGY
SURFACES
RECONSTRUCTION
CHEMISTRY
PROTEINS
Ключевые слова (''Своб.индексиров.''): energy gradients--fragment molecular orbital methods--future applications--geometry optimization--numerical criteria--silicon nanowires--molecular modeling--molecular orbitals
Аннотация: We have developed and implemented the analytic energy gradient for the bond detachment scheme in the fragment molecular orbital method (FMO) suitable to describe solids, and applied it to the geometry optimization of a silicon nanowire at several levels of theory. In addition, we have examined in detail the effects of the particular choice of the fragmentation upon the accuracy and introduced a number of numerical criteria to characterize the errors. The established route is expected to provide guidance for future applications of FMO to surfaces, solids and nanosystems. (C) 2009 Elsevier B. V. All rights reserved.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Sorokin P. B., Ovchinnikov S. G., Avramov P. V., Chernozatonskii L.A., Fedorov D.G.
Заглавие : Atypical quantum confinement effect in silicon nanowires
Место публикации : J. Phys. Chem. A. - WASHINGTON: AMER CHEMICAL SOC, 2008. - Vol. 112, Is. 40. - С. 9955-9964. - OCT 9. - ISSN 1089-5639, DOI 10.1021/jp805069b
Примечания : Cited Reference Count: 25. - Гранты: This work was in part partially supported by a CREST (Core Research for Evolutional Science and Technology) grant in the Area of High Performance Computing for Multiscale and Multiphysics Phenomena from the Japan Science and Technology Agency (JST) as well as by Russian Fund of Basic Researches (grant 08-02-01096) (L.A.C.). P.V.A. acknowledges the encouragement of Dr. Keiji Morokuma, Research Leader at Fukui Institute for Fundamental Chemistry. The geometry of all presented structures was visualized by ChemCraft software.SUP25/SUP L.A.C. acknowledges I. V. Stankevich for help and fruitful discussions. P.B.S. is grateful to the Joint Supercomputer Center of the Russian Academy of Sciences for access to a cluster computer for quantum-chemical calculations.Финансирующая организация: Japan Science and Technology Agency (JST); Russian Fund of Basic Researches [08-02-01096]
Предметные рубрики: ELECTRONIC-STRUCTURE
OPTICAL-PROPERTIES
SI
DENSITY
WIRES
EXCHANGE
ATOMS
DOTS
Ключевые слова (''Своб.индексиров.''): electric wire--energy gap--gallium alloys--mathematical models--nanostructured materials--nanostructures--nanowires--quantum confinement--quantum electronics--semiconductor quantum dots--silicon--ami methods--band gaps--blue shifts--dinger equations--linear junctions--monotonic decreases--quantum confinement effects--quantum dots--semiempirical--silicon nanowires--system sizes--theoretical models--nanocrystalline silicon--nanowire--quantum dot--silicon--article--chemistry--electron--quantum theory--electrons--nanowires--quantum dots--quantum theory--silicon
Аннотация: The quantum confinement effect (QCE) of linear junctions of silicon icosahedral quantum dots (IQD) and pentagonal nanowires (PNW) was studied using DFT and semiempirical AM1 methods. The formation of complex IQD/PNW structures leads to the localization of the HOMO and LUMO on different parts of the system and to a pronounced blue shift of the band gap; the typical QCE with a monotonic decrease of the band gap upon the system size breaks down. A simple one-electron one-dimensional Schrodinger equation model is proposed for the description and explanation of the unconventional quantum confinement behavior of silicon IQD/PNW systems. On the basis of the theoretical models, the experimentally discovered deviations from the typical QCE for nanocrystalline silicon are explained.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Rotter I., Sadreev A. F.
Заглавие : Avoided level crossings, diabolic points, and branch points in the complex plane in an open double quantum dot
Место публикации : Phys. Rev. E: AMERICAN PHYSICAL SOC, 2005. - Vol. 71, Is. 3. - Ст.36227. - ISSN 1063-651X, DOI 10.1103/PhysRevE.71.036227
Примечания : Cited References: 49
Предметные рубрики: BERRY TOPOLOGICAL PHASE
EXCEPTIONAL POINTS
GEOMETRIC PHASES
NUCLEAR REACTIONS
RESONANCE STATES
UNIFIED THEORY
S-MATRIX
CONTINUUM
REPULSION
INTERFEROMETER
Ключевые слова (''Своб.индексиров.''): branch points in the complex plane (bpcp)--diabolic points (dp)--geometric phases--riemann sheets--eigenvalues and eigenfunctions--electron energy levels--functions--hamiltonians--quantum theory--resonance--topology--semiconductor quantum dots
Аннотация: We study the spectrum of an open double quantum dot as a function of different system parameters in order to receive information on the geometric phases of branch points in the complex plane (BPCP). We relate them to the geometrical phases of the diabolic points (DPs) of the corresponding closed system. The double dot consists of two single dots and a wire connecting them. The two dots and the wire are represented by only a single state each. The spectroscopic values follow from the eigenvalues and eigenfunctions of the Hamiltonian describing the double dot system. They are real when the system is closed, and complex when the system is opened by attaching leads to it. The discrete states as well as the narrow resonance states avoid crossing. The DPs are points within the avoided level crossing scenario of discrete states. At the BPCP, width bifurcation occurs. Here, different Riemann sheets evolve and the levels do not cross anymore. The BPCP are physically meaningful. The DPs are unfolded into two BPCP with different chirality when the system is opened. The geometric phase that arises by encircling the DP in the real plane, is different from the phase that appears by encircling the BPCP. This is found to be true even for a weakly opened system and the two BPCP into which the DP is unfolded.
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Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Volkov N. V., Eremin E. V., Tarasov A. S., Varnakov S. N., Ovchinnikov S. G.
Заглавие : Bias-current and optically driven transport properties of the hybrid Fe/SiO 2/p-Si structures
Коллективы : Moscow International Symposium on Magnetism
Место публикации : Diffusion and Defect Data Pt.B: Solid State Phenomena. - 2012. - Vol. 190. - P.526-529. - ISBN 1012-0394, DOI 10.4028/www.scientific.net/SSP.190.526. - ISBN 9783037854365
Ключевые слова (''Своб.индексиров.''): hybrid structure--mis transition--photoelectric effect--schottky barrier--channel switching--comparative analysis--electron hole pairs--fe films--fe layer--ferromagnetic films--hybrid structure--optical effects--optical radiations--photogeneration--planar geometries--schottky barriers--semiconductor substrate--temperature variation--critical currents--interfaces (materials)--magnetic materials--photoelectricity--schottky barrier diodes--silicon--switching circuits--transport properties
Аннотация: Pronounced optical- and bias-current-sensitive features of the transport properties of a Fe/SiO 2/p-Si hybrid structure in planar geometry at temperature variation are investigated. Comparative analysis of two Fe/SiO 2/p-Si samples, one with a continuous Fe film and the other with two electrodes formed from a Fe layer and separated by a micron gap, shows that these features are due to the MIS transition with a Schottky barrier near the interface between SiO 2 and p- Si. Resistance of such a MIS transition depends exponentially on temperature and bias. In the structure with a continuous ferromagnetic film, the competition between conductivities of the MIS transition and the Fe layer results in the effect of current channel switching between the Fe layer and a semiconductor substrate. Within certain limits, this process can be controlled by a bias current and optical radiation. The mechanism of the optical effect is photogeneration of electron-hole pairs in the semiconductor substrate near its boundary with SiO 2 layer. В© (2012) Trans Tech Publications.
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Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Romanova O. B., Aplesnin S. S., Galyas A. I., Yanushkevich K. I., Sokolov V. V.
Заглавие : Cation-substituted TmXMn1-XS solid solutions with special magnetic and electrical properties
Коллективы : International Conference on Magnetism
Место публикации : 20th Int. Conf. on Magnetism (ICM-2015): book of abstracts. - 2015. - P.241
Предметные рубрики: Semiconductor spintronics
Материалы конференции
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Varnakov S. N., Ovchinnikov S. G., Bartolomé J., Rubin J., Badia L., Bondarenko G. V.
Заглавие : CEMS analysis of phase formation in nanostructured films (Fe/Si) 3
Коллективы : Euro-Asian Symposium "Trends in MAGnetism", "Trends in MAGnetism", Euro-Asian Symposium
Место публикации : Solid State Phenomena. - 2011. - Vol. 168-169. - P.277-280. - ISSN 1662-9779, DOI 10.4028/www.scientific.net/SSP.168-169.277
Ключевые слова (''Своб.индексиров.''): interfaces metal/semiconductor--magnetic silicides--molecular beam epitaxy technology--semiconductor and magnetic geterostructures
Аннотация: Determination of stable phases formed at the Fe/Si interface in (Fe/Si)n structure, grown by thermal evaporation in an ultrahigh vacuum system was performed using conversion electron Mossbauer spectroscopy (CEMS).
РИНЦ
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Nikolaev S. V., Ovchinnikov S. G.
Заглавие : Cluster perturbation theory in Hubbard model exactly taking into account the short-range magnetic order in 2 x 2 cluster
Коллективы :
Разночтения заглавия :авие SCOPUS: Cluster perturbation theory in Hubbard model exactly taking into account the short-range magnetic order in 2 × 2 cluster
Место публикации : J. Exp. Theor. Phys.: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2010. - Vol. 111, Is. 4. - P635-644. - ISSN 1063-7761, DOI 10.1134/S1063776110100146
Примечания : Cited References: 23. - The authors thank V. V. Val'kov for fruitful discussions of this work. This research was supported financially by the Russian Foundation for Basic Research (project nos. 09-02-90723-mob_st and 09-02-00127) and by program no. 5.7 of the Presidium of the Russian Academy of Sciences and integration project no. 40 of the Siberian Branch and Ural Division of the Russian Academy of Sciences.
Предметные рубрики: INFINITE DIMENSIONS
SYSTEMS
STATE
Ключевые слова (''Своб.индексиров.''): antiferromagnetic orders--characteristic energy--cluster perturbation theories--coulomb repulsions--density of state--dynamic mean field theories--eigenvalue problem--exact diagonalization--excited levels--finite temperatures--half-filling--hubbard--metal insulator transition temperature--nearest neighbors--numerical solution--pseudo-gap--quasiparticle spectrum--shadow zone--short-range magnetic orders--temperature evolution--zero temperatures--antiferromagnetism--eigenvalues and eigenfunctions--fermi level--hubbard model--mean field theory--metal insulator boundaries--perturbation techniques--semiconductor insulator boundaries--statistical mechanics--metal insulator transition
Аннотация: The cluster perturbation theory is presented in the 2D Hubbard model constructed using X operators in the Hubbard-I approximation. The short-range magnetic order is taken into account by dividing the entire lattice into individual 2 x 2 clusters and solving the eigenvalue problem in an individual cluster using exact diagonalization taking into account all excited levels. The case of half-filling taking into account jumps between nearest neighbors is considered. As a result of numerical solution, a shadow zone is discovered in the quasiparticle spectrum. It is also found that a gap in the density of states in the quasiparticle spectrum at zero temperature exists for indefinitely small values of Coulomb repulsion parameter U and increases with this parameter. It is found that the presence of this gap in the spectrum is due to the formation of a short-range antiferromagnetic order. An analysis of the temperature evolution of the density of states shows that the metal-insulator transition occurs continuously. The existence of two characteristic energy scales at finite temperatures is demonstrated, the larger scale is associated with the formation of a pseudogap in the vicinity of the Fermi level, and the smaller scale is associated with the metal-insulator transition temperature. A peak in the density of states at the Fermi level, which is predicted in the dynamic mean field theory in the vicinity of the metal-insulator transition, is not observed.
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Diez E., Gomez-Alcala R., Dominguez-Adame F., Sanchez A., Berman G. P.
Заглавие : Coherent carrier dynamics in semiconductor superlattices
Место публикации : Phys. Lett. A. - 1998. - Vol. 240, Is. 1-2. - P.109-111. - ISSN 0375-9601, DOI 10.1016/S0375-9601(98)00023-1
Примечания : Cited References: 7
Предметные рубрики: RABI OSCILLATIONS
Аннотация: We investigate the coherent dynamics of carriers in semiconductor superlattices driven by ac-dc electric fields. We solve numerically the time-dependent effective-mass equation for the envelope function. We find that carriers undergo Rabi oscillations when the driving frequency is close to the separation between minibands. (C) 1998 Elsevier Science B.V.
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhou J., Xia Z., Molokeev M. S., Zhang X., Peng D., Liu Q.
Заглавие : Composition design, optical gap and stability investigations of lead-free halide double perovskite Cs2AgInCl6
Место публикации : J. Mater. Chem. A: Royal Society of Chemistry, 2017. - Vol. 5, Is. 29. - P.15031-15037. - ISSN 20507488 (ISSN), DOI 10.1039/c7ta04690a
Примечания : Cited References: 42. - The present work was supported by the National Natural Science Foundation of China (Grants 91622125 and 51572023), Natural Science Foundations of Beijing (2172036), and Fundamental Research Funds for the Central Universities (FRF-TP-16-002A3). XZ acknowledges the support from the National Key Research and Development Program of China Grant No. 2016YFB0700700.
Ключевые слова (''Своб.индексиров.''): crystal growth--design for testability--energy gap--optical properties--perovskite--perovskite solar cells--solar absorbers--solar cells--structural design--band gap engineering--direct-gap semiconductor--environmentally benign--hydrothermal crystal growth--hydrothermal reaction--optoelectronic applications--rock salt structures--solar cell absorbers--crystal structure
Аннотация: The discovery of lead-free double perovskites provides a feasible way of searching for air-stable and environmentally benign solar cell absorbers. Herein we report the design and hydrothermal crystal growth of double perovskite Cs2AgInCl6. The crystal structure, morphology related to the crystal growth habit, band structure, optical properties, and stability are investigated in detail. This perovskite crystallized in a cubic unit cell with the space group Fm3m and is composed of [AgCl6] and [InCl6] octahedra alternating in a ordered rock-salt structure, and the as-obtained crystal size is dependent on the hydrothermal reaction time. Cs2AgInCl6 is a direct gap semiconductor with a wide band gap of 3.23 eV obtained experimentally and 3.33 eV obtained by DFT calculation. This theoretically predicted and experimentally confirmed optical gap is a prototype of the band gaps that are direct and optically allowed except at the single high-symmetry k-point, which didn't raise interest before but have potential applications in future technologies. Cs2AgInCl6 material with excellent moisture, light and heat stability shows great potential for photovoltaic and other optoelectronic applications via further band gap engineering. © 2017 The Royal Society of Chemistry.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : BELYAEV B. A., FROLOV G. I.
Заглавие : CONSTANT TENSION IN MAGNETIC FILM-SEMICONDUCTOR STRUCTURE DURING FERROMAGNETIC-RESONANCE
Место публикации : Zhurnal Tek. Fiz.: MEZHDUNARODNAYA KNIGA, 1980. - Vol. 50, Is. 6. - P1354-1355. - ISSN 0044-4642
Примечания : Cited References: 4
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Balaev D. A., Popkov S. I., Semenov S. V., Bykov A. A., Sabitova E. I., Dubrovskiy A. A., Shaikhutdinov K. A., Petrov M. I.
Заглавие : Contributions from Inter-grain Boundaries to the Magneto-resistive Effect in Polycrystalline High-T (C) Superconductors. The Underlying Reason of Different Behavior for YBCO and BSCCO Systems
Разночтения заглавия :авие SCOPUS: Contributions from inter-grain boundaries to the magneto-resistive effect in polycrystalline high-TC superconductors. the underlying reason of different behavior for YBCO and BSCCO systems
Место публикации : J. Supercond. Nov. Magn: SPRINGER, 2011. - Vol. 24, Is. 7. - P2129-2136. - ISSN 1557-1939, DOI 10.1007/s10948-011-1166-9
Примечания : Cited References: 30. - This work is supported by program N5 of RAS, project N7.
Предметные рубрики: HIGH-TEMPERATURE SUPERCONDUCTORS
PHASE-SLIP
TRANSPORT-PROPERTIES
TRANSITION
FIELD
COMPOSITES
BULK
TAPES
YBA2CU3O7-DELTA
DISSIPATION
Ключевые слова (''Своб.индексиров.''): bscco--ybco--intergrain boundaries--magnetoresistance--bscco--intergrain boundaries--magnetoresistance--ybco--bscco--bscco system--comparative studies--high tc superconductors--high-field--inter-grain--irreversibility lines--magneto-resistive effect--polycrystalline--resistive transition--standard measurements--weak pinning--ybco--bismuth--electric resistance--grain boundaries--high temperature superconductors--lead--magnetic fields--magnetoelectronics--magnetoresistance--magnetos--superconductivity--yttrium barium copper oxides--semiconductor metal boundaries
Аннотация: In order to clarify the mechanisms in charge of broadening of resistive transition R(T) in magnetic fields of bismuth-based polycrystalline high-T (C) superconductor (HTSC), a comparative study of Bi1.8Pb0.3Sr1.9Ca2Cu3O (x) (BSCCO) and YBa2Cu3O7-delta (YBCO) have been performed. Magnetoresistive effects and irreversibility line obtained from magnetic measurements have been studied. It was established that (1) for YBCO, the smooth part of R(T) dependence unambiguously corresponds to dissipation in the intergrain boundaries for arbitrary magnetic fields; (2) for polycrystalline BSCCO, the smooth part of R(T) dependences correspond to dissipation within intergrain boundary subsystem in the field range H 10(2) Oe only, while standard measurements of R(T) dependences in magnetic field range H 10(2) Oe reflect the dissipation processes occurring both in intergrain boundary and HTSC grain subsystems; (3) for the high-field range, the contribution from intergrain boundaries of BSCCO can be distinguished from magnetoresistance R(H) dependences obtained at high enough current density on textured samples. It is proposed that various magneto-resistive properties of these classical HTSC systems are due comparatively weak pinning in BSCCO.
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Петров, Михаил Иванович, Balaev D. A., Шайхутдинов, Кирилл Александрович, Khrustalev B. P., Aleksandrov K. S.
Заглавие : Critical current in composites consisting of a high-temperature superconductor and a semiconductor as a function of the carrier concentration
Место публикации : Doklady Physics. - 1996. - Vol. 41, Is. 2. - P.59-61. - ISSN 1028-3358
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Petrov M. I., Balaev D. A., Shaikhutdinov K. A., Khrustalev B. P., Aleksandrov K. S.
Заглавие : Critical currents in composites HTSC plus semiconductor at different concentrations of carriers
Место публикации : Dokl. Akad. Nauk. - 1996. - Vol. 346, Is. 5. - P.616-618. - ISSN 0869-5652
Примечания : Cited References: 7
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kazak N. V., Platunov M. S., Knyazev Yu. V., Ivanova N. B., Zubavichus Y. V., Veligzhanin A. A., Vasiliev A. D., Bezmaternykh L. N., Bayukov O. A., Arauzo A., Bartolome J., Lamonova K. V., Ovchinnikov S. G.
Заглавие : Crystal and local atomic structure of MgFeBO4,Mg0.5Co0.5FeBO4, and CoFeBO4: effects of Co substitution
Место публикации : Phys. Status Solidi B. - 2015. - Vol. 252, Is. 10. - P.2245-2258. - ISSN 0370, DOI 10.1002/pssb.201552143. - ISSN 15213951 (eISSN)
Примечания : Cited References: 46. - This work has been financed by the MECOM Project MAT11/23791, and DGA IMANA project E-34, Council for Grants of the President of the Russian Federation (project nos. NSh-2886.2014.2, SP-938.2015.5), and Russian Foundation for Basic Research (project nos. 13-02-00958-a, 13-02-00358-a, 14-02-31051-mol-a). The work of one of the coauthors (M.S.P.) was supported by the program of Foundation for promoting the development of small enterprises in scientific and technical sphere ("UMNIK" program).
Предметные рубрики: SPIN-GLASS BEHAVIOR
MAGNETIC WARWICKITES
SINGLE-CRYSTALS
PHASE-RELATIONS
OXYBORATE
SYSTEM
SPECTROSCOPY
ANISOTROPY
MN2OBO3
FE2OBO3
Ключевые слова (''Своб.индексиров.''): crystal structure--xanes--exafs--magnetic semiconductor--oxyborate
Аннотация: Single-crystalline MgFeBO4, Mg0.5Co0.5FeBO4, and CoFeBO4 have been grown by the ﬂux method. The samples have been characterized by X-ray spectral analysis, X-ray diffraction, and X-ray absorption spectroscopy. The X-ray absorption near-edge structure (XANES) and extended X-ray absorption ﬁne structure (EXAFS) spectra have been measured at the Fe and Co K-edges over a wide temperature range (6.5– 300 K). The composition, the charge state, and local environ- ment of both Fe and Co atoms have been determined. The effects of Co substitution for Mg on the local structural distortions have been revealed experimentally and the M–O bond anisotropy has been found.Монокристаллические образцы CoFeBO4 были выращены раствор-расплавным методом. Образцы были охарактеризованы с помощью рентгеноспектрального анализа, рентгеновской дифракции и спектроскопии поглощения рентгеновских лучей. Спектры вблизи K-края поглощения рентгеновского излучения структуры (XANES) и далее рентгеновского поглощения тонкой структуры (EXAFS) были измерены для Fe и Co в широком диапазоне температур (6.5- 300К). Состав, состояние заряда, и локальная положение и Fe и Co атомов были определены. Эффекты замещения Co магнием Mg на местные структурные искажения были выявлены экспериментально и анизотропия связи М-О была найдена.
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Xia Z., Fang H., Zhang X., Molokeev M. S., Gautier R., Yan Q., Wei S. -H., Poeppelmeier K. R.
Заглавие : CsCu5Se3: a copper-rich ternary chalcogenide semiconductor with nearly direct band gap for photovoltaic application
Место публикации : Chem. Mater. - 2018. - Vol. 30, Is. 3. - P.1121-1126. - ISSN 08974756 (ISSN), DOI 10.1021/acs.chemmater.7b05104
Примечания : Cited References: 35. - The present work was supported by the National Natural Science Foundation of China (Grants 51722202, 91622125, 51572023, 51672023, 11774239, and U1530401), and Natural Science Foundation of Beijing (Grant 2172036). K.R.P. recognizes that this work was made possible by support from the National Science Foundation (Awards DMR-1608218 and DMR-1307698). X.Z. and S.H.W. acknowledge the support from National Key R&D Program of China (Grant 2016YFB0700700).
Ключевые слова (''Своб.индексиров.''): sulfur compounds
Аннотация: Discovery of new semiconductor candidates with suitable band gaps is a challenge for optoelectronic application. A facile solvothermal synthesis of a new ternary chalcogenide semiconductor CsCu5Se3 is reported. The telluride CsCu5Te3 is also predicted to be stable. CsCu5Se3 is isostructural with CsCu5S3 (space group Pmma). The band gap calculations of these chalcogenide semiconductors using hybrid density functional theory indicate nearly direct band gaps, and their values (about 1.4 eV) were confirmed by the optical absorption spectroscopy. These alkali metal copper chalcogenides are interesting examples of copper-rich structures which are commonly associated with favorable photovoltaic application.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volkov N. V., Eremin E. V., Tsikalov V. S., Patrin G. S., Kim P. D., Seong-Cho Y., Kim D. H., Chau N.
Заглавие : Current-driven channel switching and colossal positive magnetoresistance in the manganite-based structure
Коллективы : RFBR [08-02-00259-a, 08-02-00397-a]; KRSF-RFBR [07-02-96801-a]; Division of Physical Sciences of RAS; Program 'Spin-dependent Effects in Solids and Spintronics' [2.4.2]
Место публикации : J. Phys. D. - 2009. - Vol. 42, Is. 6. - Ст.65005. - ISSN 0022-3727, DOI 10.1088/0022-3727/42/6/065005
Примечания : Cited References: 20. - This study was supported by the RFBR, Projects No 08-02-00259-a and 08-02-00397-a, the KRSF-RFBR 'Enisey-2007', Project No 07-02-96801-a and the Division of Physical Sciences of RAS, Program 'Spin-dependent Effects in Solids and Spintronics' (Project No 2.4.2 of SB RAS).
Ключевые слова (''Своб.индексиров.''): colossal magnetoresistance--electric resistance--electronic structure--magnetic field effects--magnetoelectronics--manganese--manganites--oxide minerals--schottky barrier diodes--semiconductor junctions--silicides--tunnel junctions--tunnels--bottom layers--channel switching--conducting channels--conducting layers--current-driven--current-in-plane geometries--depletion layers--ferromagnetic state--layered structures--low-resistance contacts--magnetic tunnel junctions--magneto-transport properties--manganese silicides--manganite films--new mechanisms--positive magnetoresistances--positive mr--potential barriers--spin-polarized--tunnel structures--voltage-current characteristics--current voltage characteristics
Аннотация: The transport and magnetotransport properties of a newly fabricated tunnel structure manganite/depletion layer/manganese silicide have been studied in the current-in-plane (CIP) geometry. A manganite depletion layer in the structure forms a potential barrier sandwiched between two conducting layers, one of manganite and the other of manganese silicide. The voltage-current characteristics of the structure are nonlinear due to switching conducting channels from an upper manganite film to a bottom, more conductive MnSi layer with an increase in the current applied to the structure. Bias current assists tunnelling of a carrier across the depletion layer; thus, a low-resistance contact between the current-carrying electrodes and the bottom layer is established. Below 30 K, both conducting layers are in the ferromagnetic state (magnetic tunnel junction), which allows control of the resistance of the tunnel junction and, consequently, switching of the conducting channels by the magnetic field. This provides a fundamentally new mechanism of magnetoresistance (MR) implementation in the magnetic layered structure with CIP geometry. MR of the structure under study depends on the bias current and can reach values greater than 400% in a magnetic field lower than 1 kOe. A positive MR value is related to peculiarities of the spin-polarized electronic structures of manganites and manganese silicides.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Bulgakov E. N., Sadreev A. F.
Заглавие : Current-voltage characteristics of the resonant tunnelling double-barrier structure under time-periodical perturbation
Место публикации : J. Phys.: Condens. Matter: IOP PUBLISHING LTD, 1996. - Vol. 8, Is. 45. - P.8869-8887. - ISSN 0953-8984, DOI 10.1088/0953-8984/8/45/020
Примечания : Cited References: 38
Предметные рубрики: SEMICONDUCTOR DOUBLE-BARRIER
OSCILLATING QUANTUM-WELL
DEPENDENT TRANSPORT
INFRARED-RADIATION
TUNNELING TIMES
HETEROSTRUCTURES
TRANSMISSION
MODEL
FREQUENCIES
COHERENT
Аннотация: We consider a typical semiconductor resonant tunnelling GaAs/AlGaAs/GaAs nanostructure which forms a double-barrier potential with quasienergy levels corresponding to transition frequencies in the infrared and microwave regions. Two types of dynamical perturbation of the heterostructure in the form V-1(x, t) = V(1)x cos Omega t and V-2(t) = V-2 cos Omega t are considered. We analyse numerically a reconstruction of the electron transmission through the heterostructure and the current-voltage characteristics (IVC) under the influence of these dynamical perturbations. Both weak and strong perturbations are considered. We investigate the dependences of the transmission on the electron energy and the frequency of the external field with the main accent on the case where a frequency of the perturbation is tuned to a transition between quasienergies of the double-barrier structure. it is found that these resonant phenomena give rise to new peaks and dips in the IVC. In particular, it is shown that the dipole type of perturbation V-1(x, t) gives rise to a Rabi splitting of the transmission peaks and under certain conditions to a Rabi splining of the IVC peaks and dips. We demonstrate that dynamical perturbation may induce a direct current opposite to the direction of the applied voltage, and that this phenomenon takes the form of a sharp dip which has a resonant origin. It is observed that the dipole type of perturbation V-1(x, t) of laser radiation is more effective for tuning the IVC than the first perturbation V-2(t). Also absorption and emission of energy by an electron transmitted through the DBRTS are considered.
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