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1.
We examine the dynamics of a one-dimensional crystal on a substrate with allowance for both nonlinear interaction with the
substrate and intramolecular dispersion and nonlinearity. We show that such models, with the potential chosen appropriately,
have soliton-like solutions with a distinct velocity. Such a potential allows for an independent selection of the curvature
of the potential well and the height of the potential barrier, and in this way “globally” models the real potential. We show
that such global modeling is correct to a first approximation.
Zh. éksp. Teor. Fiz. 112, 1510–1515 (October 1997) 相似文献
2.
A new mechanism is proposed for the processes taking place in metal-insulator-metal structures with a nanometer-sized insulating
gap. The dependence of the theoretical current-voltage characteristic on the substrate temperature is analyzed and compared
with experimental results.
Zh. Tekh. Fiz. 68, 139–141 (September 1998) 相似文献
3.
The formation of porous silicon is investigated by the Monte Carlo method in a model that takes account of the nonuniformity
of the charge distribution over the silicon-electrolyte interface, hole diffusion, generation, and recombination processes,
and size quantization. The structures obtained in a computer simulation for various doping levels of the crystalline substrate,
temperatures, HF concentrations, and anode current densities are presented. Analysis of nanoporous structures shows that the
porosity depends on the depth and reveals the presence of a fractal dimensionality on scales of less than 10 nm.
Pis’ma Zh. éksp. Teor. Fiz. 65, No. 9, 685–690 (10 May 1997) 相似文献
4.
A. S. Yastrebov 《Technical Physics》1999,44(8):995-997
The distribution of the potential and intensity of the electric field in dielectric structures with a nonuniform surface charge
is analyzed. Computational formulas are proposed and computational results are presented.
Zh. Tekh. Fiz. 69, 138–140 (August 1999) 相似文献
5.
In this paper the aggregates of the chiral organolithium N-Boc-2-lithiopiperidine [Boc=CO2C(CH3)3], which play an important role in the formation of chiral 2-substituted piperidines found in many alkaloid structures and medicinal compounds, have been investigated within the framework of Density Functional Theory (DFT) calculations. In the complex structures, the lithium atoms are tetra-coordinated, the diaminoalkoxide ligand is tridentate to one lithium atom and forms a chelate with the substrate which is stabilized by the solvent diethyl ether. The same type of bonding was observed for all the different ligand-bound structures; for ligands 6 and 7, which have bulky substituents, selectivity was in agreement with experiment. The results shed light on the microscopic structures of these species and suggest a potential ligand, 11, to yield high enantioselectivity. 相似文献
6.
A. M. Lipaev V. I. Molotkov A. P. Nefedov O. F. Petrov V. M. Torchinskii V. E. Fortov A. G. Khrapak S. A. Khrapak 《Journal of Experimental and Theoretical Physics》1997,85(6):1110-1118
The formation of ordered structures of charged macroparticles in a constant-current neon glow-discharge plasma is investigated.
Experiments were performed with two types of particles: thin-walled glass spheres 50–63 μm in diameter and particles of Al2O3, 3–5 μm in diameter. Formation of quasicrystalline structures is observed in the standing strata and in an artificially created
double electric layer. The formation of extended filamentary structures of macroparticles in the absence of visible stratification
of the positive column has been observed for the first time. The influence of the discharge parameters on the formation of
the ordered structures and their melting is examined. The form of the interaction potential between the charged macroparticles
is considered, as well as changes in the conditions for maintaining the discharge in the presence of high concentrations of
dust particles.
Zh. éksp. Teor. Fiz. 112, 2030–2044 (December 1997) 相似文献
7.
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
8.
O. Yu. Gorbenko R. V. Demin A. R. Kaul’ L. I. Koroleva R. Szymczak 《Physics of the Solid State》1998,40(2):263-267
A study is reported of the magnetic, electrical, and crystallographic properties of La1−x
SrxMnO3 (0.15⩽x⩽0.23) epitaxial films grown on single-crystal substrates of (001)ZrO2(Y2O3) having the fluorite structure and (001)LaAlO3 having the perovskite structure. It was found that films with close compositions for x=0.15 and 0.16, grown on different substrates, have different properties, namely, the film on a fluorite substrate is semiconducting
and has a coercive strength 30 times that of the film on a perovskite substrate; the temperature dependence of electrical
resistance of the latter film has a maximum around the Curie point T
C and follows metallic behavior for T<T
C. These differences are explained as due to different structures of the films. The x=0.23 film on the perovskite substrate has been found to exhibit a combination of giant magnetoresistance at room temperature
with a resistance of ≈300 Ω which is useful for applications. The maxima in resistance and absolute value of negative magnetoresistance
are accounted for by the existence of two-phase magnetic states in these films.
Fiz. Tverd. Tela (St. Petersburg) 40, 290–294 (February 1998) 相似文献
9.
Many structures in nature are invariant under the transformation pair, (p,r)→(b
r,−p/b), where b is some scale factor. Born’s reciprocity hypothesis affirms that this invariance extends to the entire Hamiltonian and equations
of motion. We investigate this idea for atomic physics and galactic motion, where one is basically dealing with a 1/r potential and the observations are very accurate, so as to determine the scale b≡mΩ. We find that an Ω∼1.5×10−15 s−1 has essentially no effect on atomic physics but might possibly offer an explanation for galactic rotation, without invoking
dark matter. 相似文献
10.
O. M. Belotserkovskii I. E. Zakharov A. P. Nefedov V. S. Filinov V. E. Fortov O. A. Sinkevich 《Journal of Experimental and Theoretical Physics》1999,88(3):449-459
An effective potential is proposed for the interaction between dust particles in a gas-discharge plasma which takes account
of the following physical factors: the spatial dependence of the particle charges on the floating potential of the plasma,
anisotropy of the interaction, resulting from focusing of the negatively charged particles of the drift ion current, and aspects
of screening of the dust particles by plasma electrons and ions which interact strongly with them and recombine faster in
their vicinity and on their surface. Monte Carlo calculations explain the formation of threadlike structures of dispersed
particles, and also “transverse crystallization” of these “threads” in a stratified gas-discharge plasma.
Zh. éksp. Teor. Fiz. 115, 819–836 (March 1999) 相似文献
11.
A general expression for the resonant contribution to a tunneling current has been obtained and analyzed in the tunneling
Hamiltonian approximation. Two types of resonant tunneling structures are considered: structures with a random impurity distribution
and double-barrier structures, where the resonant level results from size quantization. The effect of temperature on the current-voltage
curves of tunneling structures is discussed. The study of the effect of potential barrier profile on the d
2
I/dV
2 line shape is of interest for experiments in inelastic tunneling spectroscopy. Various experimental situations where the
inelastic component of the tunneling current can become comparable to the elastic one are discussed.
Fiz. Tverd. Tela (St. Petersburg) 40, 1151–1155 (June 1998) 相似文献
12.
M. M. Kirillova I. D. Lobov V. M. Maevskii L. V. Nomerovannaya A. A. Makhnev G. A. Bolotin F. A. Pudonin 《Journal of Experimental and Theoretical Physics》1997,85(5):925-933
The optical and magneto-optical properties of multilayered film samples of the Fe/Cu system prepared by high-frequency sputtering
on an Si(100) substrate are studied by ellipsometry and by measuring the equatorial Kerr effect (the δ
p effect) in the spectral range 0.25–7 μm. The optical characteristics, the plasma frequency ω
p and the relaxation frequency γ
0 of the conduction electrons, and the δ
p effect are found as functions of the modulation period D=12.5–100 Å. Anomalous behavior of the optical and magneto-optical characteristics is discovered in short-period Fe/Cu structures.
The results are discussed within a phenomenological theory of optical and magneto-optical properties for layered structures.
Several factors, such as the indirect exchange interaction between the iron layers, the presence of a transition layer on
the internal boundaries, the possible “magnetizing” of copper, and the formation of an fcc iron phase in the thin layers,
are taken into account in the analysis of the experimental data.
Zh. éksp. Teor. Fiz. 112, 1694–1709 (November 1997) 相似文献
13.
S. V. Meriakri 《Technical Physics》1999,44(12):1472-1476
The propagation of a microwave pulse in a ferrite thin film-substrate structure in a regime of rereflections (“ringing”) of
the acoustic component of the substrate is studied theoretically. It is shown that as a result of the interaction of microwave
pulses with the boundaries of the substrate, propagation of a microwave excitation in this system can be regarded as a propagation
of a wave packet in a periodic nonuniform medium. The basic characteristics of a propagating wave packet are obtained.
Zh. Tekh. Fiz. 69, 82–86 (December 1999) 相似文献
14.
E. A. Mulyarov N. N. Sibel’din M. L. Skorikov V. A. Tsvetkov B. Etienne 《JETP Letters》1999,70(9):621-627
Lines corresponding to localized excitonic states formed from “above-barrier” electron and/or hole states (specifically, excitation
lines of excitons formed by an electron localized in a QW and a free heavy hole) have been observed in the photoluminescence
excitation spectra of GaAs/Al0.05Ga0.95As structures with quantum wells (QWs), each containing one single-particle size-quantization level for charge carriers of
each type. A computational method is proposed that permits finding the binding energy and wave functions of excitons in QWs
taking the Coulomb potential into account self-consistently. The computed values of the excitonic transition energies agree
quite well with the experimental results.
Pis’ma Zh. éksp. Teor. Fiz. 70, No. 9, 613–619 (10 November 1999) 相似文献
15.
N. Shramchenko F. Dénoyer 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(1):51-59
A detailed investigation of the Fourier space of several Al-Pd-Mn samples with composition Al-72.6 at. %, Pd-22.9 at. %, Mn-4.5
at. % is reported. In the phase diagram of the Al-Pd-Mn ternary alloy, this composition corresponds to the so-called ξ' phase which was described as an icosahedral quasicrystalline approximant. By re-examining the Fourier space by means of
X-ray diffraction (powder patterns and single crystal precession patterns), complex structures in close relation with the
ξ'-phase have been observed. These long-range order complex structures are described as resulting from a periodic perturbation
of the ξ' structure along the c direction. Two states with periodicities c
(3 + τ) and c
(5 + τ) have been observed in this study (τ: golden mean). Structural models based on periodic arrangements of “defects” layers separating layers of phase are proposed. These two states are certainly intermediate states between the phase and the metastable decagonal quasicrystalline phase.
Received 11 April 2002 / Received in final form 24 June 2002 Published online 17 September 2002 相似文献
16.
Z. Vakar N. R. Gall’ I. V. Makarenko E. V. Rut’kov A. N. Titkov A. Ya. Tontegode M. M. Usufov 《JETP Letters》1998,67(12):1024-1028
The initial stages of growth of films of C60 molecules on a (100)Mo surface are studied by high-resolution Auger spectroscopy and atomic force microscopy under ultrahigh
vacuum conditions. It is shown that at T<750 K, after a specific coating with molecular density 1.5×31014 cm−2, which the authors term a high-temperature (HT) monolayer, has formed on the surface, crystallites in the form of “towers”
with flat tops grow on the surface. The fraction of the area occupied by towers depends strongly on the substrate temperature
and the flux density of the molecules on the surface but is virtually independent of the exposure time. At temperatures T>760 K the C60 molecules making up the crystallites desorb, while the molecules making up the HT monolayer decompose, and the carbon released
is dissolved in the interior of the substrate.
Pis’ma Zh. éksp. Teor. Fiz. 67, No. 12, 969–972 (25 June 1998) 相似文献
17.
Results of a theoretical analysis of the influence of various factors on the efficiency of excitation of space-charge waves
in thin-film semiconductor structures by a single strip Schottky barrier are presented. It is shown that to increase the efficiency
of conversion of a microwave signal into space-charge waves, it is advisable to use a Schottky barrier with a small contact
potential with optimized values of the width of the Schottky barrier and the electron concentration in the film.
Zh. Tekh. Fiz. 69, 128–130 (January 1999) 相似文献
18.
A.M. Vichare D.G. Kanhere 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1998,4(1):89-94
Density based molecular dynamics has been used to investigate the ground state structures of heterogeneous binary clusters
Al13Lin, n
= 1, 2, 3, 4, 10, 19, 20, 21. Some of these structures have also been investigated by full Kohn-Sham based calculations. Our
earlier investigations have shown that in the Al-Li cluster, the ground state configurations are the ones where the Al atoms
form a core around which the Li atoms form a “cage”. In the present work, we have chosen the well-known Al13 icosahedron as the surface over which we study the evolution of the surface coverage as the number of Li atoms increases.
On the basis of the earlier work, we expect that the Al13Li20 cluster would be the most stable and indeed our simulations do yield such a novel fivefold symmetric stable structure formed
out of purely metal atoms. This icosahedral substrate is also used to study the coverage of the aluminum surface by lithium
atoms. For a small number of Li atoms, these studies suggest that the Li-Li dimerisation is not particularly favored.
Received: 24 October 1997 / Revised: 7 April 1998 / Accepted: 29 June 1998 相似文献
19.
Short-period superlattices (SL) with periods from 7 to 22 nm were grown by MBE in the CdF2-CaF2 system on Si(111). X-ray diffraction measurements of these structures in various reflection and transmission geometries demonstrate
the possibility of producing such objects with a high crystal perfection. Specific features of diffraction from an SL with
layers possessing substantially different diffracting abilities and strains of opposite signs with respect to the substrate
are considered. The main parameters of the grown SLs have been obtained by simulation in semikinematic approximation. The
applicability of the model of a perfect SL to objects with structural defects has been demonstrated.
Fiz. Tverd. Tela (St. Petersburg) 40, 1563–1569 (August 1998) 相似文献
20.
E. García-Matres N. Stüßer M. Hofmann M. Reehuis 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,32(1):35-42
The magnetic structures of Mn1-xFexWO4 with x
= 0.0, 0.16, 0.21, 0.225, 0.232, 0.24, 0.27, 0.29, and 1.0 were refined from neutron powder diffraction data. The magnetic phase
diagram could be completed in the coexistence range of different magnetic structures up to x
= 0.29. For the magnetic state at 1.5 K a commensurate antiferromagnetic structure with a propagation vector
= (±1/4, 1/2, 1/2) was found for x
⩽ 0.22 while the magnetic spins order with
= (1/2, 0, 0) for x
≥ 0.22. In the latter phase, additionally, weak magnetic reflections indexed to an incommensurate ordering with
= (- 0.214, 1/2, 0.457) occur in the diffraction pattern up to x
= 0.29 indicating the occurence of a reentrant phase. For 0.12 ⩽
x
⩽ 0.29 the low temperature phases are separated from a magnetic high temperature phase showing only magnetic reflections indexed
to a spin arrangement with
= (1/2, 0, 0). The magnetic phase diagram is discussed qualitatively considering random superexchange between the statistically distributed
Mn2+- and Fe2+-ions in the coexistence range 0.12 ⩽
x
⩽ 0.29 of different magnetic structures related to those of pure MnWO4 and FeWO4.
Received 9 October 2002 Published online 14 March 2003 相似文献