[en] Effect of the C-sublattice vacancies on the zone structure of the VχTiyCz alloys is studied. It is shown the C-vacancy origination leads to formation of a new group of states. The perturbation, introduced by the defect into the carbide alloys spectrum is of local character and is related only to the atoms state of its closest metallic surrounding
Journal
[en] We have utilized bulk-sensitive photoelectron spectroscopy to study the valence band spectral weight distribution of d1 Mott insulators LaTiO3 and YTiO3. We observed appreciable differences in the spectra, reflecting the difference in the one-electron band width. We also found that the Ti 3d spectra of both materials are much broader than the occupied 3d bands calculated by band theories. The mean-field inclusion of the Hubbard U explains the band gap but produces even narrower bands, indicating the complete breakdown of standard mean-field theories in describing excitation spectra. We associate the observed spectra with the propagation of a hole in a system with surprisingly well suppressed charge fluctuations thereby showing characteristics of a t-J model
Journal
Verhandlungen der Deutschen Physikalischen Gesellschaft; ISSN 0420-0195; 
; CODEN VDPEAZ; v. 43(1); [1 p.]
; CODEN VDPEAZ; v. 43(1); [1 p.]
[en] We study the resonance behavior of the forbidden 600 and 222 x-ray Bragg peaks in Ge. These peaks remain forbidden in the resonant dipole scattering approximation, even taking into account the nonlocal nature of the band states. However, they become allowed at resonance if the eigenstates of the unoccupied conduction band involve a hybridization of p -like and d -like atomic states. We show that the energy dependence of the resonant behavior, including the phase of the scattering, is a direct measure of this p-d hybridization and obtain quantitative agreement with experiment. We discuss the implications of this to other materials like V2O 3 in which the resonating atom is not at a center of inversion symmetry
Journal
[en] The resonant multiple Bragg x-ray diffraction is used to study the forbidden (104) reflection in LaMnO3. Using the interference between the three-beam scattering and resonant scattering we can determine the phase of the resonant scattering. This phase is shown to be consistent with a model in which the resonant scattering is caused by the influence of the Mn-O bond length distortion rather than directly by the orbital ordering on the Mn 4p band structure
Journal