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1.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Aplesnin S. S., Romanova O. B., Korolev V. V., Sitnikov M. N., Yanushkevich K. I.
Заглавие : Magnetoimpedance and magnetocapacitance of anion-substituted manganese chalcogenides
Место публикации : J. Appl. Phys.: American Institute of Physics, 2017. - Vol. 121, Is. 7. - Ст.075701. - ISSN 00218979 (ISSN), DOI 10.1063/1.4976097
Примечания : Cited References: 26. - The reported study was funded by the Russian Foundation for Basic Research, Government of Krasnoyarsk Territory, Krasnoyarsk Region Science and Technology Support Fund to the research project No. 17-42-240079 r_sibir_a. This study was supported by the Russian Foundation for Basic Research project No. 16-52-00045 Bel_a and government work No. 114090470016.
Ключевые слова (''Своб.индексиров.''): activation energy--chalcogenides--inorganic compounds--manganese--neel temperature--carrier relaxation time--impedance spectroscopy--low and high frequencies--magnetically ordered state--magneto-resistive effect--magnetocapacitance--pyroelectric current--temperature dependence--temperature distribution
Аннотация: The magnetoresistive effect in MnSe1−XTeX manganese chalcogenides with a substitute concentration of X = 0.1 is studied by impedance spectroscopy. The magnetoimpedance above the Neel temperature is found. The obtained experimental data are explained in the framework of the model of existence of magnetic nanoareas of two types. Two activation energies in the low- and high-frequency regions are determined from the frequency and temperature dependences of the permittivity described in the Debye model. The extrema found in the temperature dependence of the pyroelectric current are consistent with the maxima in the temperature dependence of magnetization. Temperature dependence of the carrier relaxation time is established. The magnetocapacitance of the MnSe1−XTeX solid solutions is found. The change in the carrier type above the Neel temperature and the temperature of the transition to the magnetically ordered state in the MnTe nanoarea is established.
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2.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zobov V. E., Kucherov M. M.
Заглавие : Concentration dependence of the wings of a dipole-broadened magnetic resonance line in magnetically diluted lattices
Место публикации : J. Exp. Theor. Phys.: Maik Nauka-Interperiodica Publishing, 2017. - Vol. 124, Is. 1. - P.151-158. - ISSN 10637761 (ISSN), DOI 10.1134/S106377611615005X
Примечания : Cited References: 34
Ключевые слова (''Своб.индексиров.''): drug interactions--magnetic fields--magnetic resonance--magnetism--nonlinear equations--optical systems--autocorrelation functions--concentration dependence--high-frequency asymptotics--local field approximations--magnetic resonance line--modulation frequencies--strong static magnetic fields--time autocorrelation functions--autocorrelation
Аннотация: The singularities of the time autocorrelation functions (ACFs) of magnetically diluted spin systems with dipole–dipole interaction (DDI), which determine the high-frequency asymptotics of autocorrelation functions and the wings of a magnetic resonance line, are studied. Using the self-consistent fluctuating local field approximation, nonlinear equations are derived for autocorrelation functions averaged over the independent random arrangement of spins (magnetic atoms) in a diamagnetic lattice with different spin concentrations. The equations take into account the specificity of the dipole–dipole interaction. First, due to its axial symmetry in a strong static magnetic field, the autocorrelation functions of longitudinal and transverse spin components are described by different equations. Second, the long-range type of the dipole–dipole interaction is taken into account by separating contributions into the local field from distant and near spins. The recurrent equations are obtained for the expansion coefficients of autocorrelation functions in power series in time. From them, the numerical value of the coordinate of the nearest singularity of the autocorrelation function is found on the imaginary time axis, which is equal to the radius of convergence of these expansions. It is shown that in the strong dilution case, the logarithmic concentration dependence of the coordinate of the singularity is observed, which is caused by the presence of a cluster of near spins whose fraction is small but contribution to the modulation frequency is large. As an example a silicon crystal with different 29Si concentrations in magnetic fields directed along three crystallographic axes is considered. © 2017, Pleiades Publishing, Inc.
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3.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zobov V. E., Kucherov M. M.
Заглавие : On the concentration dependence of wings of spectra of spin correlation functions of diluted heisenberg paramagnets
Место публикации : JETP Letters. - 2016. - Vol. 103, Is. 11. - P.687-691. - ISSN 0021-3640, DOI 10.1134/S0021364016110138. - ISSN 1090-6487(eISSN)
Примечания : Cited References:26
Предметные рубрики: HIGH-TEMPERATURES
AUTOCORRELATION FUNCTION
SINGULAR POINT
SYSTEMS
TIME
COORDINATE
LATTICE
Аннотация: Singular points of the autocorrelation function on the imaginary time axis that is averaged over the location of spins in the magnetically dilute spin lattice with isotropic spin-spin interaction at a high temperature have been studied. For the autocorrelation function in the approximation of the self-consistent fluctuating local field, nonlinear integral equations have been proposed which reflect the separation of the inhomogeneous spin systems into close spins and other spins. The coordinates of the nearest singular points have been determined in terms of the radius of convergence of the expansion in powers of time, the coefficients of which have been calculated from recurrence equations. It has been shown that the coordinates of singular points and, consequently, the wings of the autocorrelation function spectrum at strong magnetic dilution are determined by the modulation of the local field by the nearest pairs of spins leading to its logarithmic concentration dependence.
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4.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Tkachenko V. A., Popov A.K., Myslivets S. A., Slabko V. V.
Заглавие : Extraordinary time-depended processes in the parametric interaction of counter-propagating waves
Коллективы : International Conference on Laser Optics, "Оптика лазеров", международная конференция
Место публикации : Int. Conf. Laser Optics, LO 2016: Proceedings: IEEE, 2016. - С. R838. - ISBN 9781467397353, DOI 10.1109/LO.2016.7549869
Примечания : Cited References:3
Ключевые слова (''Своб.индексиров.''): negative refractive index and negative dispersion--backward electromagnetic waves--transient parametric processes--counter-propagating waves
Аннотация: Three-wave mixing of ordinary and backward electromagnetic waves in the pulsed regime is investigated. It is shown that opposite direction of phase velocity and energy flux in the backward wave gives rise to extraordinary transient processes in the greatly enhanced optical parametric amplification and frequency-shifting nonlinear reflectivity. The discovered transients resemble time-delayed response of an oscillator on the pulsed excitation in the vicinity of its resonance. © 2016 IEEE.
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5.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zobov V. E., Lundin A. A.
Заглавие : On the effect of an inhomogeneous magnetic field and many-body localization on the increase in the second moment of multiple-quantum NMR with time
Место публикации : JETP Letters. - 2017. - Vol. 105, Is. 8. - P.514-518. - ISSN 00213640 (ISSN), DOI 10.1134/S0021364017080148
Примечания : Cited References: 27
Аннотация: A change in the time dependence of the second moment of the distribution of intensities of coherences with various orders in the spectrum of multiple-quantum NMR in a solid at the inclusion of an inhomogeneous magnetic field in the effective interaction is studied. Both the secular dipole–dipole and nonspecular twoquantum interactions are considered as nucleus–nucleus interactions, which correspond to traditional experimental realizations. It is shown that, with an increase in the magnitude of the inhomogeneous field, an exponential increase in the second moment of multiple-quantum NMR with time changes to a power-law increase. The results obtained in this work indicate that this second moment, which determines the average number of dynamically correlated spins, can be used as a convenient characteristic for studying a transition to a many-body localized state. © 2017, Pleiades Publishing, Inc.
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6.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Lundin A. A., Zobov V. E.
Заглавие : Asymptotic similarity of time correlation functions and shape of the 13C and 29Si NMR spectra in diamond and silicon
Коллективы : Institute of Chemical Physics of the Russian Academy of Science [0082-2018-0005, TSITIS AAAA-A18-118020690203]
Место публикации : J. Exp. Theor. Phys. - 2018. - Vol. 127, Is. 2. - P.305-315. - ISSN 1063-7761, DOI 10.1134/S1063776118080216. - ISSN 1090-6509(eISSN)
Примечания : Cited References: 47. - We thank V.A. Atsarkin, V.V. Demidov, F.S. Dzheparov, and E. B. Feldman for the discussion of our results. This work was supported by a subsidy allocated by the Institute of Chemical Physics of the Russian Academy of Science for the State assignment, theme 0082-2018-0005, code TSITIS AAAA-A18-118020690203.
Предметные рубрики: SPIN SYSTEMS
LINE-SHAPES
RELAXATION
SOLIDS
PARAMAGNETS
RESONANCE
Аннотация: Based on the proposed theory, we have investigated the shape of the NMR absorption spectra for 13C and 29Si nuclei in diamond and silicon crystals attributable to the internuclear dipole–dipole interaction. In accordance with the available experimental data, we have considered both crystals with a 100% content of magnetoactive isotopes and crystals with a comparatively low dilution by nonmagnetic nuclei. The time correlation functions (the first of which is the Fourier transform of the NMR spectrum) arising in an infinite chain of coupled differential equations are shown to be mutually similar with a slight time delay. The proposed theory allows the spectrum to be calculated analytically. The results obtained agree satisfactorily with the experimental ones. It is noted that the mutual similarity of the time correlation functions is probably a corollary of the development of dynamical chaos in the system.
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7.

Вид документа : Статья из сборника (выпуск продолж. издания)
Шифр издания :
Автор(ы) : Tomilin F. N., Rogova A. V., Kaufman E. V., Drevolsky A. S., Gerasimova M. A., Slyusareva E. A.
Заглавие : Solvent effect in the theoretical absorption and emission spectra of fluorescein dyes
Коллективы : International Conference on Pulsed Lasers and Laser Applications
Место публикации : International Conference on Pulsed Lasers and Laser Applications (14 ; 2019 ; 15-20 Sept. ; Tomsk). Proceedings of SPIE - The International Society for Optical Engineering. - 2019. - Vol. 11322: XIV International Conference on Pulsed Lasers and Laser Applications, AMPL 2019 (15-20 September 2019) Conference code: 156656. - Ст.113220O. - , DOI 10.1117/12.2548739
Примечания : Cited References: 13. - This work was supported by the Russian Foundation for Basic Research, project 19-02-00450
Аннотация: Fluorescein and its halogenated derivatives representing a family of homologous dyes with the gradual substitution of halogen atoms for hydrogen ones are widely used in biomedicine as fluorescent probes. This stimulates the intense experimental and theoretical studies of their fluorescent properties in aqueous solutions. However, the theoretical calculations are complicated by the necessity of taking into account the effect of a solvent (water) in the explicit form and the need for effective basic sets. This is especially important for the dyes that contain heavy atoms. In this study, the quantum-chemical investigations of the dianionic form of fluorescein and its Br- and I-substituted derivatives (eosin Y and erythrosin B) have been carried out using the time-dependent density functional theory (B3LYP functional) implemented in the GAMESS software suite. The effect of a solvent has been considered in the framework of the modified Thomas polarizable continuum model. The calculations have been made for vertical (absorption and emission) excitations in the adiabatic approximation and at the nonequilibrium solvation. The results obtained for the nonequilibrium solvation are in excellent agreement with the experimental data for fluorescein and its halogenated derivatives.
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8.

Вид документа : Статья из сборника (выпуск продолж. издания)
Шифр издания :
Автор(ы) : Sotnikov A., Schmidt H., Haghighi M. H., Gorev M. V., Suhak Y., Fritze H., Sakharov S.
Заглавие : Material parameters of Ca3TaGa3Si2O14 (CTGS) piezoelectric single crystal at extreme temperatures
Коллективы : Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium
Место публикации : Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium, EFTF/IFC 2017: Proceedings. - 2017. - P.193-197. - , DOI 10.1109/FCS.2017.8088844
Примечания : Cited References: 8
Ключевые слова (''Своб.индексиров.''): ctgs--material parameters--extreme temperatures
Аннотация: The complete set of material parameters including elastic, dielectric and piezoelectric constants as well as thermal expansion were measured by different methods for the promising piezoelectric single crystal CTGS at extreme temperatures (4.2-1170 K).
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9.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zobov V. E., Kucherov M. M.
Заглавие : On the effect of an inhomogeneous magnetic field on high-frequency asymptotic behaviors of correlation functions of spin lattices
Место публикации : JETP Letters. - 2018. - Vol. 107, Is. 9. - P.553-557. - ISSN 0021-3640, DOI 10.1134/S002136401809014X. - ISSN 1090-6487(eISSN)
Примечания : Cited References: 39
Предметные рубрики: HEISENBERG PARAMAGNET
SYSTEMS
TIME
RELAXATION
DYNAMICS
SPECTRA
Аннотация: Singular points of spin autocorrelation functions on the imaginary time axis, which determine the arguments of exponential high-frequency asymptotic behaviors, have been analyzed. It has been shown that randomly distributed inhomogeneous magnetic fields expand the wings of spectra of autocorrelation functions and, thereby, intensify the heating of a system subjected to variable magnetic fields, which are used to create effective Hamiltonians or at the saturation of inhomogeneously broadened EPR lines.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Val'kov V. V., Zlotnikov A. O.
Заглавие : Anomalies in the characteristics of electronic structure upon a quantum phase transition to a state with two order parameters and the breaking of time-reversal symmetry
Место публикации : Bull. Russ. Acad. Sci. Phys.: Allerton Press, 2016. - Vol. 80, Is. 6. - P.616-619. - ISSN 10628738 (ISSN), DOI 10.3103/S106287381606040X
Примечания : Cited References: 9
Ключевые слова (''Своб.индексиров.''): antiferromagnetism--electronic structure--phase transitions--temperature distribution--antiferromagnetic order parameter--density of state--landau expansion--periodic anderson model--quantum phase transitions--temperature dependence--time reversal symmetries--two order parameters--quantum theory
Аннотация: Based on the periodic Anderson model, microscopic expressions for the Ginzburg–Landau expansion coefficients in a phase with superconducting and antiferromagnetic order parameters are obtained. Temperature dependences of the order parameters near the temperature of the transition to this phase are established. The emergence of anomalous properties upon the quantum phase transition to the phase with two order parameters is investigated. This transition is accompanied by drastic reconstruction of the density of states, reflected by the interplay between superconductivity and antiferromagnetism. © 2016, Allerton Press, Inc.
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Berman G. P., KAGANSKY A. M.
Заглавие : Stochasticity in a many-particle system with finite-time of interaction
Место публикации : Phys. Lett. A. - 1985. - Vol. 107, Is. 3. - P.115-119. - ISSN 0375-9601, DOI 10.1016/0375-9601(85)90727-3
Примечания : Cited References: 10
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Aleksandrova I. P., Moskvich Yu. N., Rozanov O. V., Sukhovsky A. A.
Заглавие : Dislocations and time-dependent dynamics of the incommensurate phase of NH4HSEO4
Место публикации : Ferroelectr. Lett. Sect. - 1984. - Vol. 1, Is. 5-6. - P.131-134. - ISSN 0731-5171, DOI 10.1080/07315178408202410
Примечания : Cited References: 5
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Bulgakov E. N., Rotter I.
Заглавие : Spectroscopic properties of large open quantum-chaotic cavities with and without separated time scales
Место публикации : Phys. Rev. E: AMER PHYSICAL SOC, 2006. - Vol. 73, Is. 6. - Ст.66222. - ISSN 1539-3755, DOI 10.1103/PhysRevE.73.066222
Примечания : Cited References: 24
Предметные рубрики: HELMHOLTZ EQUATION
SYSTEMS
DYNAMICS
STATES
TRANSMISSION
BILLIARDS
Ключевые слова (''Своб.индексиров.''): hamiltonians--numerical analysis--phase control--quantum theory--spectroscopic analysis--wave transmission--bunimovich cavity--hamiltonian formalism--phase rigidity--quantum-chaotic cavities--cavity resonators
Аннотация: The spectroscopic properties of an open large Bunimovich cavity are studied numerically in the framework of the effective Hamiltonian formalism. The cavity is opened by attaching two leads to it in four different ways. In some cases, the transmission takes place via standing waves with an intensity that closely follows the profile of the resonances. In other cases, short-lived and long-lived resonance states coexist. The short-lived states cause traveling waves in the transmission while the long-lived ones generate superposed fluctuations. The traveling waves oscillate as a function of energy. They are not localized in the interior of the large chaotic cavity. In all considered cases, the phase rigidity fluctuates with energy. It is mostly near to its maximum value and agrees well with the theoretical value for the two-channel case.
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : BULGAKOV E. N., SADREEV A. F.
Заглавие : MESOSCOPIC RING UNDER THE INFLUENCE OF TIME-PERIODICAL FLUX - AHARONOV-BOHM OSCILLATIONS AND TRANSMISSION OF WAVE-PACKETS
Разночтения заглавия :авие SCOPUS: Mesoscopic ring under the influence of time-periodical flux: Aharonov-Bohm oscillations and transmission of wave packets
Место публикации : Phys. Rev. B: AMERICAN PHYSICAL SOC, 1995. - Vol. 52, Is. 16. - P11938-11944. - ISSN 1098-0121, DOI 10.1103/PhysRevB.52.11938
Примечания : Cited References: 25
Предметные рубрики: QUANTUM OSCILLATIONS
NETWORKS
TRANSPORT
Аннотация: The Aharonov-Bohm oscillations in the transmission probability of a one-dimensional mesoscopic ring between two electrodes are considered numerically where a time-periodical flux gamma(t)=gamma+lambda cos omega t is applied. Such a flux simulates a phase-coherent inelastic scattering due to the absorption/emission processes of modulation quanta. An increase of alternating flux amplitude lambda drastically changes the Aharonov-Bohm oscillations of the transmission though the exact period remains phi(0)=hc/e. A frequency dependence of the transmission has abrupt steps at omega=(E-E(F))/n, caused by the locking of the transmission in the nth channel where EF is the Fermi level. Moreover, for transmission of a narrow wave packet the time-periodical flux gives rise to two effects. The first is a fractioning of the input wave packet by the ring in such a way that the output wave function consists of a few separate wave packets. Their number, distance apart, and height essentially depend on the static flux gamma. The second effect is a strong space squeezing of the output wave packet.
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15.

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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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Fransson J., Eriksson O., Sandalov I. S.
Заглавие : Effects of nonorthogonality in the time-dependent current through tunnel junctions
Место публикации : Phys. Rev. B: AMERICAN PHYSICAL SOC, 2001. - Vol. 64, Is. 15. - Ст.153403. - ISSN 0163-1829, DOI 10.1103/PhysRevB.64.153403
Примечания : Cited References: 20
Предметные рубрики: LOCAL OXIDATION
TRANSPORT
DEVICES
Аннотация: A theoretical technique which allows one to include contributions from nonorthogonality of the electron states in the leads connected to a tunneling junction is derived. The theory is applied to a single-barrier, tunneling structure and a simple expression for the time-dependent tunneling current is derived showing explicit dependence of the overlap. The overlap proves to be necessary for a better quantitative description of the tunneling current, and our theory reproduces experimental results substantially better compared to standard approaches.
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Loginov V. M., Shapiro V. E.
Заглавие : Brownian particle movement in statistical uniform-fields with finite-time of some correlation decrease
Место публикации : Zhurnal Tek. Fiz. - 1981. - Vol. 51, Is. 1. - P.40-45. - ISSN 0044-4642
Примечания : Cited References: 13
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Alekseev K. N., Berman G. P., Campbell D. K., Cannon E. H., Cargo M. C.
Заглавие : Dissipative chaos in semiconductor superlattices
Место публикации : Phys. Rev. B: AMERICAN PHYSICAL SOC, 1996. - Vol. 54, Is. 15. - P10625-10636. - ISSN 0163-1829, DOI 10.1103/PhysRevB.54.10625
Примечания : Cited References: 89
Предметные рубрики: NEGATIVE DIFFERENTIAL CONDUCTIVITY
INJECTED SIGNAL
BLOCH OSCILLATIONS
COLLECTIVE EXCITATIONS
DETERMINISTIC CHAOS
MINIBAND TRANSPORT
SURFACE-PLASMONS
TIME-SERIES
LASER
VELOCITY
Аннотация: We consider the motion of ballistic electrons in a miniband of a semiconductor superlattice (SSL) under the influence of an external, time-periodic electric field. We use a semiclassical, balance-equation approach, which incorporates elastic and inelastic scattering (as dissipation) and the self-consistent field generated by the electron motion. The coupling of electrons in the miniband to the self-consistent held produces a cooperative nonlinear oscillatory mode which, when interacting with the oscillatory external field and the intrinsic Bloch-type oscillatory mode, can lead to complicated dynamics, including dissipative chaos. For a range of values of the dissipation parameters we determine the regions in the amplitude-frequency plane of the external field in which chaos can occur. Our results suggest that for terahertz external fields of the amplitudes achieved by present-day free-electron lasers, chaos may be observable in SSL's. We clarify the nature of this interesting nonlinear dynamics in the superlattice-external-field system by exploring analogies to the Dicke model of an ensemble of two-level atoms coupled with a resonant cavity field, and to Josephson junctions.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Berman G. P., Bulgakov E. N., Campbell D. K., Sadreev A. F.
Заглавие : Resonant tunneling in time-periodically modulated semiconductor nanostructures
Место публикации : Physica B. - 1996. - Vol. 225, Is. 1-2. - P.1-22. - ISSN 0921-4526, DOI 10.1016/0921-4526(96)00233-5
Примечания : Cited References: 39
Предметные рубрики: DOUBLE BARRIERS
TRANSMISSION
HETEROSTRUCTURES
Аннотация: We consider a semiconductor (AlGaAs/GaAs/AlGaAs) double-barrier resonant tunneling nanostructure (DBRTS), in which the bottom of the potential well is modulated by an external periodic potential V(t) = V-mod cos Omega t. We examine the resonance response to both mono-energetic and spatially localized incident electrons, extending previous results in three ways. First, we study numerically the resonant characteristics in the transmission probabilities as functions of both the electron's energy and the frequency of the external field. We find that new low-frequency resonant peaks appear in the frequency dependence of the transmission probabilities and discuss the origin and possible experimental observation of these peaks. Second, we develop an analytic perturbation theory (valid for small values of the parameter lambda = V-mod/h Omega) describing the processes of absorption and emission of single quanta of the modulation field and show that this perturbative treatment agrees well with the results of numerical calculations in the appropriate regions, up to and including the regime in which the one-quantum processes saturate. Third, for localized (Gaussian) incident wave packets, we show numerically that temporal modulations of the potential well in the DBRTS can induce spatial modulations in the transmitted and reflected wave packets. We develop a simple qualitative picture that explains our results. Finally, we estimate characteristic values of the parameters relevant for possible observation of these effects in laboratory experiments.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Shi, Xin, Wu, Yong, Wang, Jian Guo, Kimberg V., Zhang, Song Bin
Заглавие : X-ray transient absorption spectroscopy by an ultrashort x-ray-laser pulse in a continuous-wave IR field
Место публикации : Phys. Rev. A. - 2020. - Vol. 101, Is. 2. - Ст.023401. - ISSN 2469-9926, DOI 10.1103/PhysRevA.101.023401. - ISSN 2469-9934(eISSN)
Примечания : Cited References: 56. - Grants from the National Basic Research Program of China (Grant No. 2017YFA0403200), National Natural Science Foundation of China (Grants No. 11604197, No. 11934004, and No. 11974230), the Science Challenge Program of China (Grants No. TZ2018005 and No. TZ2016005), and the Organization Department of CCCPC are acknowledged. V.K. acknowledges financial support from Swedish Research Council within the State Contract of the Ministry of Education and Science of the Russian Federation for Siberian Federal University for Scientific Research in 2017-2019 (Project No. 3.2662.2017)
Предметные рубрики: MOLECULAR NITROGEN
TIME
DYNAMICS
PHASE
SPECTRA
DECAY
Аннотация: X-ray transient absorption spectra (XTAS) of molecules are theoretically investigated in a femtosecond x-ray pump and continuous-wave (cw) infrared (IR)-control scenario. The scheme is exemplified by a CO molecule resonantly pumped into carbon and oxygen core-excited 1s→π∗ states by a weak femtosecond x-ray pulse, while dynamic Stark shifts are induced by the cw IR-control radiation. As a result, significant shoulder structures appear in XTAS showing strong dependence on the phase of IR radiation relative to the envelope of the x-ray pulse. Due to a significant difference in the frequencies of the two pulses, the present XTAS scheme provides much clear interpretation of the dynamic Stark effects as compared to the attosecond UV transient absorption scenario. Within the suggested two-level model, where the total spectrum is decomposed as incoherent superposition of contributions from different vibrational excitations weighted by the Franck-Condon Factors, all spectral structures can be well identified and interpreted in a good agreement with the full-scale molecular simulations. Well-characterized XTAS in the proposed IR-control scheme can be applied for fine phase synchronization between IR and x-ray pulses, highly demanded in modern experiments on x-ray free-electron lasers.
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