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1.
Energy characteristics of Si1–x
Ge
x
–Si quantum-size structures with single quantum wells were calculated numerically based on a four-band k·p method. Analytical expressions for the Luttinger parameters are obtained as functions of the component composition of Si1–x
Ge
x
compounds. Analytical expressions for the energy ħω of optical band-to-band transitions are obtained in an effective mass
approximation and agree well with numerical calculations by the k·p method. This allows one to determine accurately a range of changes while varying the component compositions and thickness
of the active and barrier layers. 相似文献
2.
B. N. Zvonkov O. V. Vikhrova Yu. A. Danilov Yu. N. Drozdov A. V. Kudrin M. V. Sapozhnikov 《Physics of the Solid State》2010,52(11):2267-2270
The effect of elastic stresses (compressive, tensile) on the magnetic properties of epitaxial GaMnAs layers prepared by laser
deposition of solid-state targets in a gas atmosphere on different buffer sublayers (In
x
Ga1 − x
As and In
x
Ga1 − x
P) and substrates (GaAs, InP) has been investigated. It has been established from the investigations of magnetic-field dependences
of the Hall resistance that all layers exhibit ferromagnetic properties with the Curie temperature ∼50 K. It has been shown
that, in the case of tensile stresses in GaMnAs layers (In
x
Ga1 − x
As and In
x
Ga1 − x
P buffers and InP substrate), the anomalous Hall effect shape demonstrates a predominant orientation of the easy-magnetization
axis in the growth direction, unlike the GaMnAs layers prepared on a GaAs substrate (with compressive stresses), which demonstrate
the predominance of the component of the magnetization vector in the layer plane. 相似文献
3.
V. N. Ishchenko V. N. Lisitsyn A. M. Razhev 《Applied Physics A: Materials Science & Processing》1977,13(1):55-58
NdxLa1−xP5O14 (0.25≦x≦1) single crystals, placed within a confocal optical resonator, were pumped with ruby laser fundamental and second-harmonic
nanosecond pulses. In both cases laser oscillations at 1.05 μm exceeding in duration many times the pumping pulse were obtained. 相似文献
4.
Quantum cyclotron resonance of two-dimensional holes in strained germanium layers of the periodic heterostructure Ge-Ge1−x
Six has been observed and investigated for the first time. The results are compared with the data of electrophysical measurements
in strong magnetic fields. A clear dependence of the magnitude of the longitudinal effective mass of the holes on the absolute
magnitude of the elastic deformation of the germanium layers (splitting energy of the hole subbands) is observed.
Fiz. Tverd. Tela (St. Petersburg) 39, 2096–2100 (November 1997) 相似文献
5.
Spectral selectivity has been attained in the method of field-ion microscopy with a spatial resolution of about 5 nm and time-of-flight
determination of the photo-ion masses. Light-absorbing CdSxSe1−x
nanocrystals in a transparent glass matrix are detected by irradiating field tips made from red light filters with copper-vapor
laser radiation. The nanocrystals appeared in the photo-ion images as bright spots on a dark background.
Pis’ma Zh. éksp. Teor. Fiz. 67, No. 7, 450–454 (10 April 1998) 相似文献
6.
N. I. Sorokin E. A. Krivandina Z. I. Zhmurova B. P. Sobolev M. V. Fominykh V. V. Fistul’ 《Physics of the Solid State》1999,41(4):573-575
The fluorine-ion conductivity of anion-deficient solid solutions R
1−x
CaxF3−x
and R
1−x
BaxF3−x
having the tysonite (LaF3) structure was investigated by the impedance spectroscopy method. R
1−x
CaxF3−x
(R=La, Pr, Nd, Sm, Gd, Tb, Dy, Ho) and R
1−x
BaxF3−x
(R=La, Pr, Nd) single crystals were grown from the melt by the Bridgman-Stockbarger method. The electrophysical measurements
were performed in the frequency range 5−5×105 and temperature range 300–700 K. The temperature dependences of the electrical conductivity for the crystals studied is determined
by the migration of fluorine anions along various structural positions. It is shown that, from the standpoint of increasing
the conductivity of tysonite matrices RF3 (R=La, Pr, Nd), doping by CaF2 and BaF2 is less promising than SrF2.
Fiz. Tverd. Tela (St. Petersburg) 41, 638–640 (April 1999) 相似文献
7.
The formation of InAs1−x−y
SbxBiy/InSb and InAs1−x−y
SbxBiy/InSbyBiy strained-layer heterostructures by “capillary” LPE is simulated. The laws governing the dependence of the gap width E
g
and the thickness d of the epilayers on the conditions of the process are revealed. It is shown that because of the sharp increase in the rate
of epitaxial deposition as the LPE temperature is raised, the successful growth of epilayers of subcritical thickness is possible
only up to T<550 K. The influence of the rate of laminar flow of the liquid in the growth channel in a relaxation regime and in a continuous
pumping regime on the uniformity of the distribution of E
g
and d in the epitaxial heterostructures is analyzed. Effective combinations of parameters for carrying out the process, which ensure
the achievement of E
g
≈0.1 eV (77 K) in the active layers with variable-band-gap layers of minimal thickness, are established.
Zh. Tekh. Fiz. 67, 50–56 (July 1997) 相似文献
8.
In this paper, we report on the pulsed laser deposition of epitaxial (0002) oriented Zn1−x
Mg
x
O thin films onto (0001) sapphire substrate in O2 ambient at different deposition temperatures. Pulsed laser deposited Zn1−x
Mg
x
O films showed (0002) oriented hexagonal wurtzite structure up to 34% of Mg concentration. The bandgap of Zn1−x
Mg
x
O thin films is successfully tuned from 3.3 to 4.2 eV by adjusting the Mg concentration x=0.0 to x=0.34. Pulsed laser deposited Zn1−x
Mg
x
O thin films were characterized by XRD, AFM, SEM, PL and UV–VIS spectrometer. We have also studied the effect of deposition
temperature on to the structure, surface morphology and optical properties of Zn1−x
Mg
x
O thin films. 相似文献
9.
G. V. Astakhov V. P. Kochereshko A. V. Platonov D. R. Yakovlev W. Ossau W. Faschinger G. Landwehr 《Physics of the Solid State》1998,40(5):798-799
A study of reflectance spectra from thin ZnSxSe1−x
solid-solution layers in the region of excitonic resonances is reported. It has been found that an increase in sulfur concentration
in the layers increases the inhomogeneous broadening of the quantized polariton lines. It has been established that the inhomogeneous
line broadening in a reflectance spectrum depends on the magnitude of exciton-photon mixing; it is small in the long-wavelength
region where the photon component of the polariton is large, and large at short wavelengths where the mechanical component
dominates.
Fiz. Tverd. Tela (St. Petersburg) 40, 867–868 (May 1998) 相似文献
10.
Selective infrared multiphoton dissociation of molecules in a pulsed gasdynamic flow of small extent
The isotopically selective IR multiphoton dissociation of molecules (here CF3I) in a pulsed gasdynamic flow of small extent (the length of the flow in space is Δx
fl⩽1 cm) is investigated under conditions such that the entire flow is irradiated by high-intensity IR laser radiation. The
use of a flow of small extent permits achieving high dissociation yields of resonantly excited molecules in the entire volume
of the flow and thus to obtain a highly enriched residual gas in one radiation cycle. The method described gives a 400-fold
enrichment of the residual gas in the isotope 13C when a pulsed molecular flow of CF3I of natural isotopic composition is irradiated by just a single laser pulse. The dissociation yield in this case is practically
unity, and the selectivity α⩾10.
Zh. Tekh. Fiz. 69, 35–41 (January 1999) 相似文献
11.
A. A. Rajabi 《Few-Body Systems》2005,37(4):197-213
A mathematical method is presented for solving the Schr?dinger equation for a system of identical body forces. The N-body forces are more easily introduced and treated within the hyperspherical harmonics. The problem of the N-body potential has been used at the level of both classical and quantum mechanics.
The hypercentral interacting potential is assumed to depend on the hyperradius x = (ξ12 + ξ22 + ⋯ + ξN−12)1/2 only, where ξ1,ξ2,…,ξN−1 are Jacobi relative coordinates which are functions of N-particle relative positions r12,r23,…,rN1. The problem of the harmonic oscillator and the Coulomb-type potential has been widely studied in different contexts.
Using the N-body potential V(x) = ax2 + bx − (c/x) as an example, and assuming an ansatz for the eigenfunction, an exact analytical solution of the Schr?dinger equation for
an N-body system in three dimensions is obtained. This method is also applicable to some other types of potentials for N-identical interacting particles. 相似文献
12.
Narrow equidistant peaks are recorded in the microphotoluminescence spectra of GaAs/AlxGa1−x
As superlattices with thin barrier layers. An approximate method, consisting of the reduction of a three-dimensional problem
to a one-dimensional problem, is developed for calculating the electronic spectrum of quantum dots of arbitrary shape. It
is shown on the basis of this method that the observed peaks may be due to the formation of electronic states of a new type,
which are produced as a result of the overlapping of fluctuations of the thicknesses of adjacent wells in structures with
thin barriers. The equidistant spectrum of the new states is accounted for by the nearly quadratic dependence of the diameter
of the overlap regions on the coordinate in the plane of the layers.
Pis’ma Zh. éksp. Teor. Fiz. 63, No. 4, 260–265 (25 February 1996) 相似文献
13.
A theory of the generalized conductivity for the normal component of the Hall effect is developed. It is shown that the normal
Hall effect coefficient R
0 of microscopically inhomogeneous magnetic alloys GdZnxCu1−x
, which at low temperatures consist of ferro-, antiferro-, and paramagnetic phases, can be described satisfactorily on the
basis of an effective-medium theory. The experimentally observed relationship between the coefficient R
0(x) and the resistivity ρ(x) is obtained.
Fiz. Tverd. Tela (St. Petersburg) 41, 98–102 (January 1999) 相似文献
14.
The heating of electrons in an AlxGa1−x
As/GaAs (x>0.42) heterostructure in a lateral (directed along the heterointerfaces) electric field is studied. Population inversion
on the size-quantization subbands of the Γ valley of GaAs and a giant population inversion between the X-valley states of
AlxGa1−x
As and Γ-valley states of GaAs are predicted. The possibility of using these inversions for achieving stimulated IR emission
is discussed.
Pis’ma Zh. éksp. Teor. Fiz. 68, No. 1, 73–77 (10 July 1998) 相似文献
15.
V. A. Kutasov L. N. Luk’yanova P. P. Konstantinov G. T. Alekseeva 《Physics of the Solid State》1997,39(3):419-422
A study has been made of the thermoelectric and galvanomagnetic properties of n-Bi2Te3−x
Sex solid solutions (x=0.3 and 0.36) in the temperature range 80–300 K. The lowest carrier concentrations, (0.8–1)×1018 cm−3, were obtained by displacing the solid solution from the stoichiometric to a Te-rich composition. At such carrier concentrations,
the second subband in the conduction band of n-Bi2Te3−x
Sex is not filled, which results in a growth of mobility because of the absence of interband scattering, and brings about an
increase of thermoelectric efficiency in the 80–120-K range.
Fiz. Tverd. Tela (St. Petersburg) 39, 483–487 (March 1997) 相似文献
16.
V. Ya. Aleshkin A. A. Andronov A. V. Antonov N. A. Bekin V. I. Gavrilenko D. G. Revin B. N. Zvonkov E. R. Lin’kova I. G. Malkina E. A. Uskova 《JETP Letters》1996,64(7):520-524
The infrared radiation from hot holes in InxGa1−x
As/GaAs heterostructures with strained quantum wells during lateral transport is investigated experimentally. It is found
that the infrared radiation intensities are nonmonotonic functions of the electric field. This behavior is due to the escape
of hot holes from quantum wells in the GaAs barrier layers. A new mechanism for producing a population inversion in these
structures is proposed.
Pis’ma Zh. éksp. Teor. Fiz. 64, No. 7, 478–482 (10 October 1996) 相似文献
17.
Yu. V. Piskunov V. V. Ogloblichev I. Yu. Arapova A. V. Sadykov A. P. Gerashchenko S. V. Verkhovskii 《Journal of Experimental and Theoretical Physics》2011,113(5):826-834
The effect of charge disorder on the formation of an inhomogeneous state of the electron system in the conduction band in
BaPb1 − x
Sb
x
O3 superconducting oxides is investigated experimentally by NMR methods. The NMR spectra of 17O are measured systematically, and the contributions from 17O atoms with different cation nearest surroundings are identified. It is found that microscopic regions with an elevated spin
density of charge carriers are formed within two coordination spheres near antimony ions. Nuclei of the superconducting phase
of the oxide (regions with an elevated antimony concentration) microscopically distributed over the sample are detected in
compounds with x = 0.25 and 0.33. Experiments in which a double resonance signal of the spin echo of 17O-207Pb and 17O-121Sb are measured in the metal phase of BaPb1 − x
Sb
x
O3 oxides are carried out for the first time. The constants of indirect heteronuclear spin-spin 17O-207Pb interaction are determined as functions of the local Knight shift 207
Ks. The estimates of the constants of the indirect interaction between the nuclei of the nearest neighbors (O-Pb and Pb-Pb atoms)
and analysis of evolution of the NMR spectra of 17O upon a change in the antimony concentration are convincing evidence in favor of the development of a microscopically inhomogeneous
state of the electron system in the metal phase of BaPb1 − x
Sb
x
O3 oxides. 相似文献
18.
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
19.
Yu. P. Smirnov A. E. Sovestnov V. A. Shaburov A. V. Tyunis 《Physics of the Solid State》1999,41(9):1399-1401
The electronic structure of Rh, Pt, In, and Sn in the mixed-valence systems Eu(Rh1−x
Ptx)2 and U(In1−x
Snx)3 has been studied by the x-ray K line-shift method. It has been found that the occupation of the Rh 4d-shell in Eu(Rh1−x
Ptx)2 is higher than that in the metal, and that it grows with decreasing Eu valence (i.e., with increasing 4f-shell occupation). The electronic structure of Pt, In, and Sn in Eu(Rh1−x
Ptx)2 and U(In1−x
Snx)3 does not depend on the Eu and U valence and is practically the same as in the metals. These features in the electronic structure
of Rh, Pt, In, and Sn in Eu(Rh1−x
Ptx)2 and U(In1−x
Snx)3 suggest that the electron released in the f
n
→ f
n
−1+e transitions, rather than transferring to the common conduction band, remains localized at the Eu and U atoms.
Fiz. Tverd. Tela (St. Petersburg) 41, 1529–1531 (September 1999) 相似文献
20.
Results are presented of the first measurements of infrared reflection spectra of Zn1−x
CdxSe films (x=0–0.55; 1) grown on a GaAs substrate by molecular-beam epitaxy. It is shown by a mathematical analysis of the experimental
spectra that the investigated Zn1−x
CdxSe alloy system manifests a unimodal rearrangement of its vibrational spectrum as the composition is varied.
Fiz. Tverd. Tela (St. Petersburg) 41, 982–985 (June 1999) 相似文献