On the scattering of a two-dimensional gas of free charge carriers by coulomb centers at the surface of semiconductors
On the scattering of a two-dimensional gas of free charge carriers by coulomb centers at the surface of semiconductors
S.A. Venkstern and S.N. Kozlov
We carry out a detailed analysis of different approaches to the problem of the scattering of a two-dimensional gas of electrons by an unscreened Coulomb potential. On the basis of numerical estimates for the oblique (100) surface of silicon, we draw the conclusion that the Born approximation is inapplicable, whereas the validity of the quasiclassical approximation is not in doubt. It is shown that in attempting a crude account of screening, several authors have used internally inconsistent premises.
Show AbstractMass operator of electrons interacting with acoustic phonons in the vicinity of a van hove singularity
Mass operator of electrons interacting with acoustic phonons in the vicinity of a van hove singularity
Yu.P. Drozhzhov
The interaction of acoustic phonons with electrons near a saddle-point singularity is investigated. An expression for the mass operator is obtained by a method which does not make use of perturbation theory.
Show AbstractSeveral questions in quasilinear plasma theory
Several questions in quasilinear plasma theory
L.S. Kuz'menkov and P.A. Polyakov
In the framework of the quasilinear theory of plasma with radiative braking taken into account, we examine the change in the average distribution function and its first moments. It is shown that during the propagation of Langmuir waves in the plasma the radiative effects lead to an additional change in the distribution function. For this the total energy of the particles of the plasma is not conserved. We make numerical estimates of the rate of loss of the plasma energy. Effects due to radiative braking are manifested also during the propagation of electromagnetic waves and lead to the entrainment of the particles by the wave. The corresponding change of the distribution function with tine is found.
Show AbstractOn polarization effects in neutrino annihilation of colliding electron-positron beams
On polarization effects in neutrino annihilation of colliding electron-positron beams
В.K. Kerimov, A.M. Tikhomirov and S.Kh. Buzardan
We evaluate the differential and total cross sections for the process of annihilation of longitudinally polarized electrons and positrons into neutrino-antineutrino pairs due to the (S,P,T) and (V,A) versions of the weak interaction of neutral currents of neutrinos and electrons. It is shown that taking the polarization of the initial particles into account enables one to distinguish the contributions of the (S,P,T) and (V,A) types of neutral-current coupling. For parallel transverse polarization of е^+ and е^-, only the S and T versions of the interaction contribute; for antiparallel transverse polarization, only the P and T versions. In the (V, A) case with transverse polarization of е^+ and е^- the cross section has azimuthal asymmetry.
Show AbstractEffect of plasmon dispersion in inelastic scattering of fast electrons with deep hole excitation in fietals
Effect of plasmon dispersion in inelastic scattering of fast electrons with deep hole excitation in fietals
F.A. Zhivopistsev and F.E. Komas
We investigate the effect of plasmon dispersion in the inelastic scattering of fast electrons with excitation of a deep hole in metals. It is shown that allowance for plasmon dispersion leads to the replacement of singular satellite peaks in the energy-transfer spectrum by finite maxima. With the growth of the energy transfer the differential cross section of the processes falls off according to an exponential law.
Show AbstractCalculation of epr spectra of elements of the iron group using second-order perturbation theory (II)
Calculation of epr spectra of elements of the iron group using second-order perturbation theory (II)
A.I. Terent'evskii and V.N. Lazukin
The spin-Hamiltonian formalism for paramagnetic systems is examined for ions of the iron group. More exact analytical expressions are obtained for the angular dependence of the fine EPR spectra for different symmetries. The results of the theoretical investigation are presented graphically for a number of systems.
Show AbstractOn a single method of symbolic representation of cascade and parallel connections of normal n-wire networks
On a single method of symbolic representation of cascade and parallel connections of normal n-wire networks
V.I. Shestakov
In this paper we set forth a method of symbolic representation of cascade and parallel connections of normal n-wire networks, i.e. processions of non-interacting two-terminal networks. The complexity of the representation of the cascade and parallel connections of the normal n-wire networks'by means of a procession of n two-terminal networks is proportional to the number n, whereas if matrices are used it is proportional to the square of this number. Therein lies the main advantage of the "procession" method proposed in this article over the usual matrix method of describing such connections of normal n-wire networks.
Show AbstractDetermination of the resolving power of spatial modulators of light
Determination of the resolving power of spatial modulators of light
A.A. Volodin, V.G. Mal'shakov, A.I. Nagaev and V.N. Parygin
We examine theoretically the resolving power of a spatial modulator of light based on an electro-optic crystal. The problem is solved under the assumption that the density of charge deposited on the surface of the crystal is proportional to the current density in the electron beam. The results obtained in this paper permit estimation of the resolving power of a modulator as a function of its parameters at any level of contrast of the image that is formed.
Show AbstractDiffraction of cylindrical waves on annular periodic structures
Diffraction of cylindrical waves on annular periodic structures
Yu.A. Pirogov, N.F. Ryapolov, and N.A. Simonov
We examine the diffraction of cylindrical waves on a grating of perfectly conducting rings of finite thickness. By the method of partial regions we obtain expressions for the field scattered by the structure. For gratings with narrow spacings we give approximate conditions for the resonant transmission of cylindrical waves through a structure with large outer and-arbitrary inner radii of the annular structure. It is shown that for small inner radii of the rings a more efficient interaction of the electron current with the harmonics of the retarded waves is possible than in the planar case.
Show AbstractOn the kinetics of slow relaxation of charge on the surface of germanium over a wide time interval
On the kinetics of slow relaxation of charge on the surface of germanium over a wide time interval
S.N. Kozlov and N.L. Levshin
The kinetics of slow relaxation of charge on actual surfaces of germanium с are investigated over a wide time interval (5x10^(-4)—10^5 sec). It is shown that the leakage of the excess charge of slow states in a vacuum 10^(-4)—10^(-6)Pa occupies 5 to 7 orders of time. The wide spectrum of characteristic time constants of the slow states Is explained by a distribution of the height and width of the barriers separating the slow states from the bulk of the semiconductor. Possible mechanisms of charge exchange between the slow states and the bulk of the semiconductor are discussed.
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