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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    JETP letters 65 (1997), S. 439-445 
    ISSN: 1090-6487
    Keywords: 71.27.+a ; 71.30.+h ; 74.20.Mn ; 74.72.−h
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We present a theory of superconductivity in doped insulators. In the magnetic metal state of the compound we obtain the self-consistency equations for the superconducting state in the spin-dependent impurity bands of both extended and localized states in the initial insulator gap. A BCS-type triplet pairing field is considered. We show that the superconducting gap in which single-electron extended states do not exist is overlapped by the distribution of the localized states. The formation of a latent superconducting gap is discussed in connection with the unusual properties of high-T c compounds.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of experimental and theoretical physics 85 (1997), S. 27-33 
    ISSN: 1090-6509
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A method for obtaining the relativistic wave equation for the bound states of a system of interacting charged particles without consideration of spin is proposed. An expansion of the wave function of the system in a complete basis of orthonormal wave functions of vacuum states for each type of particle is used in this equation. It is shown that this equation contains two types of solutions for a proton + electron system. The first type corresponds to Bohr bound states. Exact expressions are obtained for the energy and Bohr radius of the ground state with consideration of the finite mass of the particles. An influence of the energy of translational motion of the system as a whole on the structure of the atomic levels in the laboratory frame is predicted. This effect is due to the finite value of m/M, and leads to removal of the degeneracy of the levels with respect to orbital angular momentum l, and partial removal of the degeneracy with respect to its projection. The second type of solution represents states of the system with binding energy $$E_b = M + m - \sqrt {|M^2 - m^2 |} $$ and an exponential wave function damping radius equal to the Compton wavelength of the electron. A complete description of this state requires consideration of the electronic vacuum polarization.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1090-6509
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The results of an experimental investigation of low-temperature optical spectra and phase relaxation of electronic excitations of Pr3+ impurity ions in a Y2SiO5 crystal are reported. It is established that at low temperatures spectral lines are broadened by a mechanism that is uncharacteristic for crystals and is due to the interaction of impurity ions with two-level systems. The constants characterizing the interaction of Pr3+ impurity ions with phonons and two-level systems are found.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of experimental and theoretical physics 87 (1998), S. 956-966 
    ISSN: 1090-6509
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We propose a model of electron pairing via spin fluctuations in doped insulators. The bare states for the superconducting condensate correspond to impurity bands in the original band gap of the undoped material. We obtain a complete set of equations for the superconducting state. We show that fermion pairing in impurity bands of extended states is possible, and thus so is superconductivity, if localized spin-0 bosons are produced. The latter are necessarily accompanied by localized spin-1 bosons, which are responsible for the relationship between singlet and triplet pairing channels of quasiparticles.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of experimental and theoretical physics 89 (1999), S. 500-507 
    ISSN: 1090-6509
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The energy dependence of the back reflectivity in the dynamical diffraction of x rays at a Bragg angle of π/2 (back diffraction) in perfect crystals of cubic symmetry (silicon) is investigated theoretically. In this case strict backscattering is realized only under the conditions of multiple diffraction. The features of the influence of multiple diffraction on back reflection in the energy range near the nuclear resonance radiation energy of 14.41 keV for 57Fe nuclei, specifically in the six-wave case, including the silicon (1,9,9) reflection (with an energy of 14.57 keV), which can be investigated experimentally with high energy resolution (1 meV) using synchrotron radiation and a monochromator developed for nuclear resonant absorption, are thoroughly studied. It is shown that the back reflectivity observed under the conditions of multiple diffraction has several maxima on the plot of its energy dependence with a value at each maximum smaller than half, in contrast to two-wave diffraction, where there is one maximum with a value close to unity.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of experimental and theoretical physics 84 (1997), S. 875-880 
    ISSN: 1090-6509
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The theory of condensed excited matter, the so-called Rydberg matter (RM), is examined briefly. Explicit results are given for several physical quantities, notably, the work function and the resistivity, for which experimental results exist. The most important aspects of the experiments, which are fully described elsewhere, are discussed. Large densities of Rydberg species are formed in the experiments with cesium vapor in contact with carbon (graphite) surfaces. The resistivity of the RM formed is found to be 10−2–10−3 Ω·m under varying conditions, while theory gives the order of 10−3 Ω·m. The work function is experimentally found to be less than 0.7 eV, perhaps even less than 0.5 eV. Two different methods were used to extract this quantity from thermionic diode data. These work function values are much lower than reported for any known material, especially at the high temperatures, and they thus give strong support for the description of RM as a very dilute metal. Theory gives values ranging from 0.6 down to 0.2 eV, depending on the principal quantum number, which is estimated to be n=12–14 from the lifetime calculations and from the known pressure. Supporting evidence is found from spectroscopic studies of RM, from jellium calculations, and from recent confirming experiments. From the good agreement between theory and experiment we conclude that RM exists.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of experimental and theoretical physics 90 (2000), S. 160-172 
    ISSN: 1090-6509
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract AbstractThe band structure of cuprates as a doped 2D insulator is modeled assuming that the excess charge carriers are associated with the corresponding substitution atoms, and the phase diagram of the paramagnetic states as a function of the degree x of doping at zero temperature is studied. The Hamiltonian contains electronic correlations on impurity orbitals and hybridization between them and the initial band states of the insulator. It is shown that the change in the electronic structure of a doped compound includes the formation of impurity bands of distributed and localized electronic states in the initial insulator gap. It is established that in the case of one excess electron per substitution atom the spin fluctuations (1) give rise to an insulator state of the doped compound for x 〈 x thr, 1, (2) lead to a superconducting state for x thr, 1 〈 x 〈 x thr, 2, and (3) decay as x 〉 x thr, 2 increases further, and the doped compound transforms into a paramagnetic state of a “poor” metal with a high density of localized electronic states at the Fermi level.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Radiophysics and quantum electronics 13 (1970), S. 706-707 
    ISSN: 1573-9120
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Radiophysics and quantum electronics 14 (1971), S. 1054-1057 
    ISSN: 1573-9120
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Radiophysics and quantum electronics 22 (1979), S. 839-842 
    ISSN: 1573-9120
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Type of Medium: Electronic Resource
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