Confinement of an Electron in an Image Potential and an External Electrostatic Field

The quasi-classical approximation is used to determine the positions of the classical turning points upon motion of an electron that is bound by an image field and a constant homogeneous electric field of the same direction. Power expansions of the coordinates of the turning points in a wide range of electron energies and field strengths are obtained. The mechanism of one-dimensional confinement of an electron, which determines a completely discrete spectrum of states, is described. The dependence of the spatial width of the confinement region on the field strength and electron energy is determined. The dependences of the electron energy in different states on the external field strength are calculated numerically. Quasi-classical quantization is performed, and the dependence of the electron energy on the width of the confinement region is determined. The energy interval of a maximum density of electron states is found, which is determined by the dependence of the width of the confinement region on the electric field strength.     

Interlayer current near the edge of an InAs/GaSb double quantum well in proximity with a superconductor

We investigate charge transport through the junction between a niobium superconductor and the edge of a two-dimensional electron-hole bilayer, realized in an InAs/GaSb double quantum well. For the transparent interface with a superconductor, we demonstrate that the junction resistance is determined by the interlayer charge transfer near the interface. From an analysis of experimental I?V curves, we conclude that the proximity-induced superconductivity efficiently couples electron and hole layers at low currents. The critical current demonstrates periodic dependence on the in-plane magnetic field, while it is monotonic for the field that is normal to the bilayer plane.     

Fröhlich resonance in the AsSb/AlGaAs system

The optical absorption in a metal-semiconductor metamaterial based on the AlGaAs matrix has been investigated. The key feature of this material is the presence of random arrays of metallic AsSb nanoinclusions modifying its dielectric properties. It has been shown that the presence of such arrays in the material leads to resonance absorption of light by surface plasmons in AsSb nanoinclusions in the incident photon energy range from 1.37 to 1.77 eV. The experimental spectrum of the extinction coefficient at an energy of 1.48 eV exhibits a resonance peak with the half-width equal to 0.18 eV. The extinction coefficient for AsSb nanoinclusions in the AlGaAs matrix has been calculated in terms of the Mie theory. The calculated spectrum of the extinction coefficient also includes a resonance peak with the energy and half-width equal to 1.48 and 0.18 eV, respectively. The calculated plasma energy for free-standing nanoinclusions in vacuum is 7.38 eV.     

Exact nonrelativistic expressions for the tensor for scattering of light by atoms

Exact nonrelativistic analytical expressions are derived for dipole two-photon transitions between arbitrary multiplets of the hydrogen atom and positive hydrogenlike ions. The result is expressed in terms of a single Gauss hypergeometric function and polynomials whose degrees increase linearly with the number of nodes of the bound states of the quantum system. The cross sections of elastic scattering of light by K-and L-shells of the hydrogen atom are given as an example. It is demonstrated that by expanding the discrete-spectrum wave functions in ultraspherical polynomials it is also possible to obtain analytical expressions of the cross sections of two-photon transitions between states described by the Simons model potential. The basis consisting of Chebyshev polynomials is shown to be the best expansion basis, and the coefficients of such an expansion are given for a broad range of parameters of the problem. Calculation of the polarizability of the 5S-state of the rubidium atom is chosen as an example. Finally, the results are compared with the experimental data and the theoretical results of other researchers. Zh. éksp. Teor. Fiz. 111, 816–830 (March 1997)     

Defects in the GaAs and InGaAs layers grown by low-temperature molecular-beam epitaxy

The problem of defect formation in the GaAs and InGaAs layers grown by low-temperature molecular-beam epitaxy is discussed. The effect of growth conditions (temperature and flux ratio between the elements of groups III and V) on the morphology of growth surface, internal structure, type, and concentration of electrically-and optically active defects is analyzed. A comparison is made between the defect formation processes occuring during the epitaxial growth and post-growth annealing of the layers. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 63–72, December, 2006.     

Investigations in the field of acyl group carriers

Conclusions Two representatives of phosphate ester derivatives of pantothenonitrile have been obtained: the methyl ester of D-(+)-4-C-[2-O-mesylpantothenonitrilyloxy(phenoxy)phosphonyl]-N-benzyloxycarbonylserine and the ethyl ester of D-(+)-4-C-[2-O-mesylpantothenonitrilyl(phenoxy)phosphonyl]-N-benzyloxycarbonylserylglycine.Khimiya Prirodnykh Soedinenii, Vol. 5, No. 3, pp. 174–176, 1969