Electronic structure and transport properties of CeNi9In2

We investigated CeNi9In2 compound, which has been considered as a mixed valence (MV) system. Electrical resistivity vs. temperature variation was analysed in terms of the model proposed by Freimuth for systems with unstable 4f shell. At low temperature the resistivity dependence is consistent with a Fermi liquid state with a contribution characteristic of electron-phonon interaction. Ultraviolet photoemission spectroscopy (UPS) studies of the valence band did not reveal a Kondo peak down to 14 K. A difference of the spectra obtained with photon energies of low and high photoionization cross sections for Ce 4f electrons indicated that 4f states are located mainly close to the Fermi energy. The peaks related to f_{5/2}^1 and f_{7/2}^1 final states cannot be resolved but form a plateau between -0.3 eV and the Fermi energy. X-ray photoemission spectroscopy (XPS) studies were realized for the cerium 3d level. The analysis of XPS spectra within the Gunnarsson-Sh\"onhammer theory yielded a hybridization parameter of 104 meV and non-integer f level occupation, being close to 3. Calculations of partial densities of states were realized by a full potential local orbital (FPLO) method. They confirm that the valence band is dominated by Ni 3d states and are in general agreement with the experiment except for the behavior of f-electrons.Comment: 10 pages, 5 figure

Evidence of momentum dependent hybridization in Ce2Co0.8Si3.2

We studied the electronic structure of the Kondo lattice system Ce2Co0.8Si3.2 by angle-resolved photoemission spectroscopy (ARPES). The spectra obtained below the coherence temperature consist of a Kondo resonance, its spin-orbit partner and a number of dispersing bands. The quasiparticle weight related to the Kondo peak depends strongly on Fermi vectors associated with bulk bands. This indicates a highly anisotropic hybridization between conduction band and 4f electrons - V_{cf} in Ce2Co0.8Si3.2.Comment: 6 page

Gender Pay Gaps in the Former Soviet Union: A Review of the Evidence

The goal of this paper is to examine the patterns and movements of the gender pay gaps in the countries of the former Soviet Union (FSU) and to place them in the context of advanced economies. We survey over 30 publications and conduct a meta-analysis of this literature. Gender pay gaps in the region are considerable and above the levels observed in advanced economies. Similar to advanced economies, industrial and occupational segregation widens the gaps in the FSU countries, whereas gender differences in educational attainment tend to shrink them. However, a much higher proportion of the gaps remain unexplained, pointing toward the role of unobserved gender differences related to actual and perceived productivity. Over the last 25 years, the gaps contracted in most FSU countries, primarily due to the reduction in the unexplained portion. Underlying the contraction at the mean are different movements in the gap across the pay distribution. Although the glass-ceiling effect has diminished in some FSU countries, it has persisted in others. We investigate the reasons underlying these findings and argue that the developments in the FSU region shed new light on our understanding of the gender pay gaps

The effective increase in atomic scale disorder by doping and superconductivity in Ca3Rh4Sn13

A comprehensive study of the electronic structure, thermodynamic and electrical transport properties reveals the existence of inhomogeneous superconductivity due to structural disorder in Ca3Rh4Sn13 doped with La (Ca3−x La x Rh4Sn13) or Ce (Ca3−x Ce x Rh4Sn13) with superconducting critical temperatures T*c higher than those (T c ) observed in the parent compounds. The T − x diagrams and the entropy S(x) T isotherms document well the relation between the degree of atomic disorder and separation of the high-temperature T*c and T c -bulk phases. In these dirty superconductors, with the mean free path much smaller than the coherence length, the Werthamer–Helfand–Hohenber theoretical model does not fit well the H c2(T) data. We demonstrate that this discrepancy can result from the presence of strong inhomogeneity or from two-band superconductivity in these systems. Both the approaches very well describe the H − T dependencies, but the present results as well as our previous studies give stronger arguments for the scenario based on the presence of nanoscopic inhomogeneity of the superconducting state. A comparative study of La-doped and Ce-doped Ca3Rh4Sn13 showed that in the disordered Ca3−x Ce x Rh4Sn13 alloys the presence of spin-glass effects is the cause of the additional increase of T*c in respect to the critical temperatures of disordered Ca3−x La x Rh4Sn13. We also revisited the nature of structural phase transition at T*~130÷170 K and documented that there might be another precursor transition at higher temperatures. Raman spectroscopy and thermodynamic properties suggest that this structural transition may be associated with a CDW-type instability

Electronic structure of Fe 2 VGa

We present the band structure calculations on the Heusler alloy Fe 2 VGa which shows a pseudogap at the Fermi level. The compound is found to be nonmagnetic. We observed, however, that an atomic disorder which has been experimentally observed can lead to the behaviour characteristic of the heavy-Fermion compounds. The antisite Fe defects locate the d states forming a narrow d-band at the Fermi level

Lanthanide Contraction in RENi5RENi_5 (RE~=~La, Ce, Nd, Sm, Eu, Gd, Tb,~Yb) Compounds Studied with Band Structure Calculations

Full potential linearized augmented plane wave band structure calculations were performed for hexagonal $RENi_5$ (RE = rare earth) compounds in order to investigate reproducibility of lanthanide contraction by ab initio studies. The a and c parameters were optimised using a paraboloid fit, starting from the same initial values for all compounds studied. The trend in lattice parameters across the RE series obtained from the calculations was found to be in general agreement with experimental data. A comparison of results obtained by generalized gradient approximation and generalized gradient approximation with additional Coulomb correlations calculations is presented for several double counting schemes