Probe Raman spectroscopy of sodium uranyl-acetate microcrystals

The technique for recording Raman spectra in uranium compounds using a probe minispectrometer with a multielement radiation detector has been developed. A selective filter, which reflects exciting laser radiation and transmits Raman signals, has been used to suppress the exciting radiation. It is shown that the technique developed makes it possible to record Raman spectra from a small amount (~10^–5 g) of sodium uranyl-acetate polycrystals in a wide spectral range for several seconds.     

Multielectron approach to the electronic structure and mechanisms of superconductivity in high-Tc cuprates

A review of recent results for the doping dependence of the Fermi surface and mechanism of pairing in LaSrCuO obtained within the LDA+GTB multielectron approach is given. Both magnetic and phonon contributions to the d_x²-y²-gap are considered.     

Ion implantation into metals simultaneously irradiated by electrons

It has been revealed that concomitant irradiation by 1-keV electrons changes the depth distributions of the N and C atoms implanted with the energies of 10 and 30 keV in nickel and stainless steel samples. Instead of a single peak, the distribution has two peaks; one peak is closer to the surface and the other is located deeper than that in the absence of electron irradiation. The electron radiation effect is attributed to the formation of a band above the Fermi level in the atomic system whereto the metal electrons are transferred due to the electron bombardment excitation. The electrons in this band have a quite long lifetime and increase the mobility of impurity atoms.     

Uniformly frustrated XY model without a vortex-pattern ordering

The uniformly frustrated XY model with f=1/3 on a dice lattice is shown to possess an accidental degeneracy of its ground states so well developed that the difference between the free energies of fluctuations does not lead to the stabilization of a particular vortex pattern down to zero temperature. Nonetheless, at low temperatures the system is characterized by a finite helicity modulus whose vanishing (at a finite temperature) is related to the dissociation of half-vortex pairs.