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1.
Yu. P. Gnatenko O. A. Shigil’chev E. Rutkovskii G. Contreras-Puente M. Cardenas-Garcia 《Physics of the Solid State》1998,40(4):564-568
Low-temperature photoluminescence, exciton reflection, and multiphonon resonant Raman scattering spectra of Ni-and Co-doped
Zn1−x
MnxTe crystals were investigated. Intense emission occurs in a broad spectral region (1100–17 000 cm−1) in the crystals containing Ni atoms. It is caused by intracenter transitions involving Mn2+ ions and transitions between the conduction band and a level of the doubly charged acceptor. The features of the exciton
photoluminescence and multiphonon resonant Raman scattering involving longitudinal-optical (LO) phonons at various temperatures
are investigated. The insignificant efficiency of the localization of excitons on potential fluctuations in the Zn1−x
MnxTe:Co crystals is established. A temperature-induced increase in the intensity of the 5LO multiphonon resonant Raman scattering
line due to the approach of the conditions for resonance between this line and the ground exciton state is observed in these
crystals.
Fiz. Tverd. Tela (St. Petersburg) 40, 616–621 (April 1998) 相似文献
2.
I. Ya. Gerlovin Yu. K. Dolgikh V. V. Ovsyankin Yu. P. Efimov I. V. Ignat’ev E. E. Novitskaya 《Physics of the Solid State》1998,40(6):1041-1046
This paper describes investigations of the photoluminescence spectra of heterostructures containing short-period type-II GaAs/AlAs
superlattices grown both within the regime where the heterojunction is smoothed, and in a regime where it is not smoothed,
in the temperature range 10–40 K. A quantitative analysis of the experimental data shows that the quenching of exciton luninescence
in the majority of cases is characterized by a single value of the activation energy E
2=8±1 meV which coincides with the value of the binding energy of an X-Γ exciton. It is concluded that the primary reason for quenching in this temperature interval is thermal dissociation of
the exciton into a pair of free carriers whose delocalization is accompanied by nonradiative recombination at traps. It is
observed that smoothing the heterojunction leads to an increase in the probability of quenching by 1–2 orders of magnitude
on the average.
Fiz. Tverd. Tela (St. Petersburg) 40, 1140–1146 (June 1998) 相似文献
3.
A study has been carried out of the temperature dependences of luminescence spectra on a large number of CdTe/ZnTe structures
differing in average thickness, 〈L
z〉=0.25–4 monolayers (ML), and CdTe layer geometry (continuous, island type). The influence of geometric features in the structure
of ultrathin layers on linewidth, the extent of lateral localization of excitons, their binding energy, and exciton-phonon
coupling is discussed. It is shown that in island structures there is practically no lateral exciton migration. The exciton-phonon
coupling constant in a submonolayer structure has been determined, Γph=53 meV, and it is shown that in structures with larger average thicknesses Γph is considerably smaller. Substantial lateral exciton migration was observed to occur in a quantum well with 〈L
z〉=4 ML, and interaction with acoustic phonons was found to play a noticeable part in transport processes. It has been established
that the depth of the exciton level in a quantum well and structural features of an ultrathin layer significantly affect the
temperature dependences of integrated photoluminescence intensity.
Fiz. Tverd. Tela (St. Petersburg) 41, 717–724 (April 1999) 相似文献
4.
A. V. Kudinov Yu. G. Kusraev B. P. Zakharchenya V. N. Yakimovich 《Physics of the Solid State》1998,40(5):823-825
Polarized photoluminescence of Cd1−x
MnxTe crystals in a weak magnetic field has been studied in Faraday and Voigt geometries. A simple method is proposed to determine
the exciton mobility edge and excitonic magnetic-polaron energy. “Forbidden” polarization components of the recombination
radiation have been experimentally detected. It has been established that the moments of magnetic polarons are oriented predominantly
along the {111} axes.
Fiz. Tverd. Tela (St. Petersburg) 40, 894–896 (May 1998) 相似文献
5.
W. Ossau D. R. Yakovlev C. Y. Hu V. P. Kochereshko G. V. Astakhov R. A. Suris P. C. M. Christianen J. C. Maan 《Physics of the Solid State》1999,41(5):751-756
II–VI quantum-well structures containing a 2DEG of low density have been investigated by means of polarized photoluminescence,
photoluminescence excitation and reflectivity in external magnetic fields up to 20 T. The spin splittings of the exciton X and the negatively charged exciton X
− are measured as a function of the magnetic field strength. The behavior of the magnetic-field-induced polarization degree
of the luminescence line related to X
− demonstrates the formation process of negatively charged excitons from excitons and free carriers polarized by the external
magnetic field. We have determined the binding energies of the trion formed either with the heavy-hole or the light-hole exciton.
The optically detected magnetic resonance (ODMR) technique was applied for the first time to study the optical transition
processes in a nanosecond timescale. The electron ODMR was observed with the detection on either the direct exciton or the
negatively charged exciton X. Further evidence for the interaction of excitons with the electrons of the two-dimensional gas are demonstrated by a combined
exciton-cyclotron resonance line observed in reflectivity and luminescence excitation, shake-up processes observed in photoluminescence,
as well as inelastic and spin-dependent scattering processes.
Fiz. Tverd. Tela (St. Petersburg) 41, 831–836 (May 1999)
Published in English in the original Russian journal. Reproduced here with stylistic changes by the Translation Editor. 相似文献
6.
The pump-probe experimental method is used to investigate the effect of photoexcited carriers on the dynamics of the exciton
absorption spectra of GaAs / AlxGa1–x
As-multilayer quantum wells. Use of the method of moment analysis for processing the results makes it possible to identify
the simultaneous contribution of changes in oscillator strength and width of the exciton lines in the saturation of exciton
absorption. It was found that the oscillator strength recovers its initial value in the course of the first 100–130 ps, whereas
broadening and energy-shift of the exciton lines is observed for 700–800 ps. These are the first experimental measurements
of the excitation densities at which the oscillator strength of the excitonic state saturates when the latter is perturbed
only by free-electron-hole pairs, and when it is perturbed only by other excitons.
Fiz. Tverd. Tela (St. Petersburg) 40, 1130–1133 (June 1998) 相似文献
7.
L. V. Butov A. V. Mintsev A. I. Filin K. Eberl 《Journal of Experimental and Theoretical Physics》1999,88(5):1036-1044
The kinetics of indirect photoluminescence of GaAs/AlxGa1−x
As double quantum wells, characterized by a random potential with a large amplitude (the linewidth of the indirect photoluminescence
is comparable to the binding energy of an indirect exciton) in magnetic fields B≤12 T at low temperatures T≥1.3 K is investigated. It is found that the indirect-recombination time increases with the magnetic field and decreases with
increasing temperature. It is shown that the kinetics of indirect photoluminescence corresponds to single-exciton recombination
in the presence of a random potential in the plane of the double quantum wells. The variation of the nonradiative recombination
time is discussed in terms of the variation of the transport of indirect excitons to nonradiative recombination centers, and
the variation of the radiative recombination time is discussed in terms of the variation of the population of optically active
excitonic states and the localization radius of indirect excitons. The photoluminescence kinetics of indirect excitons, which
is observed in the studied GaAs/AlxGa1−x
As double quantum wells for which the random potential has a large amplitude, is qualitatively different from the photoluminescence
kinetics of indirect excitons in AlAs/GaAs wells and GaAs/AlxGa1−x
As double quantum wells with a random potential having a small amplitude. The temporal evolution of the photoluminescence
spectra in the direct and indirect regimes is studied. It is shown that the evolution of the photoluminescence spectra corresponds
to excitonic recombination in a random potential.
Zh. éksp. Teor. Fiz. 115, 1890–1905 (May 1999) 相似文献
8.
S. O. Romanovskii A. V. Sel’kin I. G. Stamov N. A. Feoktistov 《Physics of the Solid State》1998,40(5):814-815
A study is made of the effect of electric fields on the exciton states of β-ZnP2 crystals (T=77 K) in structures with Schottky barriers formed by depositing semitransparent electrically-conducting InSnO2 films on the crystal surface. The observed changes in the exciton optical reflection spectra when an electrical potential
is applied to a barrier are explained by the shift and broadening of the exciton level caused by the Stark effect. The experimental
data are compared with calculations based on a theory of exciton optical reflection from planar spatially nonuniform structures.
Fiz. Tverd. Tela (St. Petersburg) 40, 884–886 (May 1998) 相似文献
9.
I. A. Kudryavtseva E. A. Vasil’chenko A. Ch. Lushchik Ch. B. Lushchik 《Physics of the Solid State》1999,41(3):388-395
The spectrum of luminescent F centers generated in high-purity KCl crystals by 7–10.2-eV photons has been measured at 230 K. The pulsed annealing of these
centers (250–550 K), as well as the dependence of the efficiency of stable F-center generation on irradiation temperature (80–500 K) has been studied. The efficiencies of F
− and Cl
3
−
-center generation are maximum under direct optical creation of self-trapped excitons in the region of the Urbach intrinsicabsorption
tail. Besides the exciton decay with formation of F centers and mobile H centers, a high-temperature exciton decay channel which involves creation of cation defects stabilizing the H centers has been revealed.
Fiz. Tverd. Tela (St. Petersburg) 41, 433–441 (March 1999) 相似文献
10.
A. V. Chernenko N. G. Kalugin O. A. Kusnetsov 《Journal of Experimental and Theoretical Physics》1998,87(2):337-341
This paper reports on the first investigation made of luminescence of Ge/Ge1−x
Six heterostructures at liquid-helium temperatures in a magnetic field of up to 14 T. The luminescence lines observed in the
spectra are due to both free and impurity bound excitons in Ge layers. The diamagnetic shift of the quasi-two-dimensional
exciton has been measured. From the experimental data the size of the exciton has been estimated to be 75–90 Å.
Zh. éksp. Teor. Fiz. 114, 619–627 (August 1998) 相似文献
11.
Exciton absorption spectra in high-quality β-ZnP2 single crystals have been investigated at T=1.7 K for various directions of the wave vector and various polarization states of the radiation. It has been unambiguously
established that the additional high-energy A series, which in some works has been called a D series and ascribed to ZnP2 crystals, of so-called “rhombic” symmetry,1,8,10,11 is an intrinsic exciton of the β-ZnP2 series. A mixed mode has been detected for the first time, and the energy of the longitudinal exciton has been determined.
The selection rules for the exciton transitions have been analyzed by a group-theoretical approach, and the symmetry of the
nS states of the single exciton has been established on the basis of the experimental data — Γ
2
−
(z).
Fiz. Tverd. Tela (St. Petersburg) 41, 193–202 (February 1999) 相似文献
12.
I. M. Bolesta V. V. Vistovskii N. V. Gloskovskaya M. R. Panasyuk L. I. Yaritskaya 《Physics of the Solid State》2011,53(4):799-803
It has been shown using atomic-force microscopy that the PbI2 impurity is embedded in the CdI2 crystal lattice in the form of nanocrystalline inclusions. The model of a high-energy cation exciton related to the 3
P
2 state of a free Pb2+ ion has been considered for the impurity absorption (excitation) band at 3.23 eV. The resonance narrow photoluminescence
bands with the split absorption band at 3.12 and 3.20 eV have been compared with the emission of a free Frenkel exciton. It
has been demonstrated that, in the temperature range 25–45 K, there arises a self-trapped exciton state, and the main role
in its formation is played by the bending vibrations of the CdI2 crystal lattice. The potential barrier separating the self-trapped state from the free exciton is 23 meV. The photoluminescence
band at 2.4 eV is assigned to the emission of the self-trapped high-energy cation exciton of PbI2 in the CdI2 crystal lattice. 相似文献
13.
S. G. Ovchinnikov 《JETP Letters》1996,64(1):25-31
The Fermi and Bose quasiparticle spectrum in copper oxides is studied in a many-band p-d model taking account of the strong electronic correlations. It is shown that hole-doped systems possess a Bose mode — a spin
exciton — which is associated with the singlet-triplet excitation of the two-hole ground-state term of CuO4 clusters. Intercluster hopping leads to fermion-boson interaction with a spin exciton as the intermediate boson. Such a mechanism
does not exist for n-type systems.
Pis'ma Zh. éksp. Teor. Fiz. 64, No. 1, 23–28 (10 July 1996) 相似文献
14.
We have investigated the absorption spectrum of thin films of the superionic conductor RbCu4Cl3I2 synthesized on NaCl crystalline substrates. It is shown that the electron and exciton excitations in the energy interval
3–6 eV are associated with optical transitions in the CuHal sublattice, and the edge of the fundamental band is controlled
by optical transitions in the Cu(II)Hal sublattice. It is found that the large band gap of this compound (E
g
=3.86 eV) in comparison with those of CuCl and CuI is a result of the small number of Cu ions in the second coordination sphere.
The temperature dependence of the spectral position and half-width of the low-temperature exciton band reveals features associated
with the phase transitions γ→β (T
c1=170 K) and β→α (T
c2=220 K) and with disordering of the cation sublattice attendant to the transition to the superionic state.
Fiz. Tverd. Tela (St. Petersburg) 40, 1022–1026 (June 1998) 相似文献
15.
16.
I. V. Kavetskaya N. V. Zamkovets N. N. Sibeldin V. A. Tsvetkov 《Journal of Experimental and Theoretical Physics》1997,84(2):406-416
Luminescence spectra of sufficiently pure n-type indium antimonide crystals (N
D−N
A=(1–22)·1014 cm−3) in a magnetic field of up to 56 kOe, at temperatures of 1.8–2 K, and high optical pumping densities (more than 100 W/cm2) have been studied. More evidence of the existence of electron-hole liquid stabilized by magnetic field has been obtained,
and its basic thermodynamic parameters as functions of magnetic field have been measured. When the magnetic field increases
from 23 to 55.2 kOe, the liquid density increases from 3.2·1015 to 6.7·1015 cm−3, the binding energy per electron-hole pair rises from 3.0 to 5.2 meV, and the binding energy with respect to the ground exciton
level (work function of an exciton in the liquid) rises from 0.43 to 1.2 meV.
Zh. éksp. Teor. Fiz. 111, 737–758 (February 1997) 相似文献
17.
Band-edge optical spectra of Cd1−x
FexTe solid solutions differ substantially from those of undoped CdTe. The pattern of the change in photoluminescence spectra
with increasing Fe concentration is connected with a change in radiative recombination channels.
Fiz. Tverd. Tela (St. Petersburg) 40, 897–899 (May 1998) 相似文献
18.
The paper considers the effect of a magnetic field B on the transport of neutral composite particles, namely excitons, in weakly disordered two-dimensional (2D) systems. In the
case of classical transport (when the interference of different paths is neglected), the magnetic field suppresses exciton
transport, and the static diffusion constant D(B) monotonically drops with B. When quantum-mechanical corrections due to weak localization are taken into account, D(B) becomes a nonmonotonic function of B. In weak magnetic fields, where the magnetic length is much larger than the exciton Bohr radius, ℓB=(ℏc/eB)1/2≫a
B
=ε ℏ2/μe
2,a positive magnetodiffusion effect is predicted, i.e., the exciton mobility should increase with B.
Zh. éksp. Teor. Fiz. 114, 359–378 (July 1998) 相似文献
19.
A vibronic charge-transfer exciton, which is a pair of Jahn-Teller electron and hole polarons, is considered as a possible
cause of the appearance of the Müller phase in the virtual ferroelectric SrTiO3 and the “green” luminescence in the virtual ferroelectric KTaO3. The two “green” luminescence bands can be associated with emission from two states of a typical intrinsic defect, viz.,
a vibronic charge-transfer exciton trapped by an oxygen vacancy and an isolated vibronic charge-transfer exciton. In both
cases the “green” luminescence corresponds to the recombination of the electron and the hole in the vibronic charge-transfer
exciton, which is accompanied by the emission of light. The properties of the Müller phase can be attributed to mixing of
the normal state and states of the vibronic charge-transfer exciton phase when they interact with polarization in the soft
SrTiO3 matrix under the conditions of a pseudo-Jahn-Teller (pseudo-JT) effect on a soft TO mode of the displacement type. In this
case the vibronic charge-transfer exciton phase forming the low-lying excited states has “order-disorder” degrees of freedom
and exists at temperatures significantly below the point of the order-disorder ferroelectric transition in SrTiO3 at T=T
Q≈37 K. The corresponding lowering of the symmetry of the vibronic charge-transfer exciton phase to polar symmetry leads to
the possibility of a long-period incommensurate phase in such excited states, which arises as a result of the appearance of
a Lifshitz invariant. The valence-band state making the largest contribution of the pseudo-JT effect corresponds to a wave
vector equal to the critical wave vector of the incommensurate vibronic charge-transfer exciton phase. When the temperature
is lowered, the pseudo-JT distortion increases down to ∼T
Q and subsequently saturates in accordance with the saturation of the dielectric constant. The basic assumption in the model
is that the temperature T=T
Q corresponds to the narrow temperature range for the transition from an intermediate to a strong pseudo-JT effect under the
conditions for the realization of polarization tunneling states. The appearance of a significant admixture of states of the
modulated ferroelectric vibronic charge-transfer exciton phase to the ground state under the conditions for the realization
of polarization tunneling states at low temperatures provides an explanation for the principal properties of the Müller phase.
Fiz. Tverd. Tela (St. Petersburg) 40, 907–909 (May 1998) 相似文献
20.
A. A. Klochikhin 《Physics of the Solid State》1998,40(5):819-820
A unified method is developed for describing the steady-state luminescence of exciton fluctuation states for weak excitation
in different disordered systems. The phononless luminescence band is found to be formed by “radiative” states of the fluctuation
tail in the density of states, i.e., by states for which nonradiative states are either nonexistent or have a low probability.
The shape of the emission spectra calculated including the phonon interaction is in good agreement with experimental luminescence
spectra of α Si:H and of solid solutions of ZnSe(1−c)Tec and CdS(1−c)Sec.
Fiz. Tverd. Tela (St. Petersburg) 40, 890–891 (May 1998) 相似文献