Green luminescence in diffusion-doped layers of zinc selenide

Diffusion-doped layers with a green emission band dominating in the room-temperature luminescence spectrum are obtained by annealing single-crystal zinc selenide substrates in tellurium and zinc vapors.     

Spatial macroscopic structure of a pulsed microsecond discharge in barrier-metal gaps with a nonuniform electric field distribution

Electric and spatial characteristics of a pulse-periodic microsecond barrier discharge are investigated in different geometries—triangular prism, plate, and corrugated electrode—that are in contact with a dielectric plate and form a dihedral angle with it. It is established that, in the space of the dihedral angle, the regions of discharge represent alternating cylindrical layers with the axes lying on the contact line. The first conducting layer is formed at some distance from the contact edge of the electrode. The number of layers and their localization are determined by the angle formed between an electrode and the dielectric plate. A physical model explaining the main features of the structure formation is proposed.     

Prediction of the properties of two-phase composites with a piezoactive component

The effective dielectric, piezoelectric, and elastic constants of two-phase macroscopically piezoactive 3-0 and 3-3 composites are calculated. It is assumed that one of the components is a polarized ferroelectric ceramic material and the other is an inactive material with variable elastic properties. The limiting case when the elastic compliances of the inactive material tend to infinity (porous ferroelectric ceramics) is considered. The adequacy of this model to production technologies of piezoelectric composites is discussed. Computational results are compared with experimental data.     

Energy spectra and temperature distributions of clusters produced during ion-beam sputtering of metals

A method for evaluating the energy spectra and temperature dependences of the yield of neutral and charged clusters that consist of N≥5 atoms and are produced by ion bombardment of metals is proposed. The results are presented in the form of simple formulas. Theoretical energy spectra of clusters emitted as a result of bombarding niobium, tantalum, and iron targets by atomic ions of gold or xenon and temperature dependences of the yield of silver clusters produced by bombarding the targets with xenon ions are compared with experimental data.

     

Calculation of the asymmetry parameters of the angular distribution and of the spin polarization of Auger electrons for open-shell atoms

By means of the multichannel Hartree-Fock-Dirac method, the parameters β and α₂ of the angular distribution of Auger electrons and the parameter β₂ of their spin polarization are calculated for sodium, krypton, xenon, barium, mercury, and excited argon. Relevant Coulomb matrix elements are determined by using orthogonal multielectron initial-and final-state wave functions for intermediate-type coupling in a relativistic approximation. Exchange interaction is taken into account in all calculations. A comparison of the results of calculations performed in the frozen-core approximation and those obtained with orthogonal initial-and final-state wave functions reveals that the relaxation of core orbital processes has only a slight effect on the anisotropy parameters of the angular distribution. The resulting values of the parameters β, α₂, and β₂ are compared with the results of different calculations.     

Calculations of phase reflection diffraction gratings

Intensities of principal diffraction maxima for a phase reflection diffraction grating with a rectangular groove profile were calculated by the Fresnel method, using a special algorithm. The procedure under consideration enables us to perform high-efficiency calculations of diffracted-beam characteristics and can be used extensively to optimize diffraction-grating parameters.__________This revised version was published online in May 2005 with a correction on affiliation.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 38–41, November 2004.     

Electron Metal-Dielectric Phase Transitions in Semiconductors under Pressure

The effect of uniform pressure on the character of metal-dielectric transitions in compensated weakly- and highly doped semiconductors (WHDCS) is considered. The influence of hybridization of resonance quasilocalized impurity states with band continuum states on the transition is shown. Minimum metallic conductivities in p-CdSnAs₂ are determined for Mott and Anderson transitions. Special features of the metal-dielectric transformation in weakly-doped narrow- and high energy-gap semiconductors are discussed for the case of hydrogen-like impurities. Anderson localization in WHDCS is also considered. Phase diagrams are presented.