Modeling the photoelectron spectra of the valence O2p-band of zinc oxide by the Xα-scattered wave method

The photoelectron spectra (PES) of the valence O2p-band of zinc oxide are modeled by Xα-scattered wave cluster calculations in a wide range of incident quantum energies hv (from 30 to 150 eV and 1253.6 eV). For the Zn₁₀O₁₀ cluster, the calculated intensities of PES reproduce well the specific features of the experimental spectra. It is shown that Zn3d-electrons participate in covalent binding of zinc and oxygen. The admixture of the Zn3d-states in the hybrid orbitals of the valence band is ≈7%. Deceased. Translated fromZhurnal Struktumoi Khimii, Vol. 38, No. 5, pp. 877–886, September-October, 1997.     

Resonant tunneling in superconducting structures with <Emphasis Type="Italic">s</Emphasis> and <Emphasis Type="Italic">d</Emphasis> symmetry of order parameter

Resonant tunneling processes are studied in superconducting junctions of low transparency with the order parameter of the electrodes of different symmetry. A general equation of the resonant current is derived within the Green’s function formalism for the junctions of arbitrary dimensionality. The phase dependence of the supercurrent averaged over the set of localized states is analyzed for superconducting junctions with an isotropic order parameter. A numerical analysis of the resonant current transport in junctions with high-T _c superconducting electrodes with the d symmetry of the order parameter was carried out.     

Heteronuclear compounds formed in the systems based on Fe(II), Fe(III), Al(III), SO 42? , Cl?-H2O-OH?, and NH3

The possibility of synthesizing heteronuclear compounds in the systems based on Fe(II), Fe(III), Al(III), SO₄²⁻, Cl⁻-H₂O-OH⁻, and NH₃ was studied. A mathematical model based on data on the potentiometric titration was developed. The elemental and phase composition and the structure of the compounds synthesized were determined by the XPA, DTA and NMR methods to optimize the conditions of the synthesis.     

Resonant Josephson tunneling through S-I-S junctions of arbitrary size

The Josephson tunneling current in S-I-S structures where the main current transport channel is resonant tunneling through an isolated localized state is calculated using the Bogolyubov-de Gennes equations. It is shown that the efficiency of equilibrium Josephson resonant tunneling is determined only by the ratio of the width of the resonance level to the absolute value of the order parameter for the superconducting electrodes with arbitrary relationships among the system parameters. Zh. éksp. Teor. Fiz. 112, 342–352 (July 1997)     

Nonequilibrium fluctuations of a thin metal diffuse film exposed to microwave radiation

Nonlinear fluctuations of the electron energy distribution function in a microwave-irradiated thin diffuse metal film are calculated in the nonlinear approximation for various energy relaxation models. The spectral density of the resulting nonequilibrium fluctuations is calculated as a function of the microwave-radiation power for various ratios between the electron-phonon and electron-electron relaxation rates.     

The association and complexation equilibria in the system D-glucitol—nickel(II)—water

A joint study using polarimetry, spectrophotometry, and mathematical modeling revealed the formation of 1: 1, 2: 1, and 4: 4 outer-sphere complexes of nickel(II) ions with neutral D-glucitol (H₆Glc-ol), viz., {[Ni(H₂O)_n]?(H₆Glc-ol)aq}₂+, {[Ni(H₂O)_n]₂?(H₆Glc-ol)aq}⁴⁺, and {[Ni(H₂O)_n]₄?[(H₆Glc-ol)aq]₄}⁸⁺ in a weakly acidic medium. In aqueous solutions, D-glucitol forms tetramers. For each form, the constant of formation and the specific optical rotation was calculated.     

Microscopic theory of phase slip in a narrow durty superconducting strip

Phase slip in a narrow durty superconducting strip is studied theoretically using the Usadel formalism. Coordinate-dependent Green’s functions corresponding to the saddle point of the trajectory in the configuration space have been calculated, and the dependence of the free energy barrier on the transport current, magnetic field, and temperature has been obtained.     

Electronic thermal properties of the interface between a normal metal and a high-temperature superconducting material

The electron thermal flux and electron thermal conductivity of the interface between a normal metal and a high-temperature superconductor (HTSC) are calculated using quasiclassical equations. Calculations are made for various values of the interface transparency and various orientations of the axes of a HTSC crystal. It was shown that compared with an interface between a normal metal and an “ordinary” superconductor (s-type symmetry, isotropic order parameter), the thermal conductivity of an HTSC-normal-metal interface is substantially higher and has a nonactivation dependence. The thermal properties were calculated for various interface models, including mirror and diffuse, and also for various potential barrier profiles. An analysis is made of the possibility of using devices based on normal-metal-HTSC interfaces for bolometric and microrefrigerator applications.     

Detailed XPS and UPS studies of the band structure of zinc oxide

The X-ray photoelectron spectra of zinc oxide were measured in a wide range of quantum energies (30–150 and 1253.6 eV). It is shown that the form of the spectrum of the valence O2p-band depends on the energy of the incident quantum. The most probable reason for the change in the form of the O2p-band spectra is an admixture of Zn3d-electrons, which, along with Zn4s-electronst take part in covalent bonding of Zn and O. The dependence of the integral intensity ratio of the O2p-band to the intensity of the Zn3d peak on hv was analyzed, due to which the percent of the admixture of the Zn3d-states in the O2p-band was determined to be 9%. The stoichiometry and the depth of the profile of the concentration ratio were calculated taking into account the fraction of the Zn3d-electrons participating in the bond. Deceased. Translated fromZhurnal Struktumoi Khimii, Vol. 38, No. 5, pp. 868–876, September-October, 1997.     

Investigation of various operation modes of a miniature superconducting detector of microwave radiation

Nonequilibrium electron and phonon distribution functions have been calculated for a metallic absorber of a promising miniature superconducting detector irradiated by microwave radiation. The response of this detector has been calculated, and it has been shown that this detector can operate in either the photon counter mode or bolometric mode in dependence on the degree of nonequilibrium of the phonon subsystem.