On the interpretation of spin-polarized electron energy loss spectra

We study the origin of the structure in the spin-polarized electron energy loss spectroscopy (SPEELS) spectra of ferromagnetic crystals. Our study is based on a 3d tight-binding Fe model, with constant onsite Coulomb repulsion U between electrons of opposite spin. We find it is not the total density of Stoner states as a function of energy loss which determines the response of the system in the Stoner region, as usually thought, but the densities of Stoner states for only a few interband transitions. Which transitions are important depends ultimately on how strongly umklapp processes couple the corresponding bands. This allows us to show, in particular, that the Stoner peak in SPEELS spectra does not necessarily indicate the value of the exchange splitting energy. Thus, the common assumption that this peak allows us to estimate the magnetic moment through its correlation with exchange splitting should be reconsidered, both in bulk and surface studies. Furthermore, we are able to show that the above mechanism is one of the main causes for the typical broadness of experimental spectra. Finally, our model predicts that optical spin waves should be excited in SPEELS experiments.Comment: 11 pages, 7 eps figures, REVTeX fil

Resonant Auger spectroscopy at the L2,3 shake-up thresholds as a probe of electron correlation effects in nickel

The excitation energy dependence of the three-hole satellites in the L3-M4,5M4,5 and L2-M4,5M4,5 Auger spectra of nickel metal has been measured using synchrotron radiation. The satellite behavior in the non-radiative emission spectra at the L3 and L2 thresholds is compared and the influence of the Coster-Kronig channel explored. The three-hole satellite intensity at the L3 Auger emission line reveals a peak structure at 5 eV above the L3 threshold attributed to resonant processes at the 2p53d9 shake-up threshold. This is discussed in connection with the 6-eV feature in the x-ray absorption spectrum.Comment: 8 pages, 4 figures; http://prb.aps.org/abstract/PRB/v58/i7/p3677_

Layered Semiconductors and Related Systems

The general properties of the layered transition metal dichalcogenides and the possibility to modify these materials by intercalation are reviewed. Examples are given of experimental results obtained by using angle-resolved photoelectron spectroscopy and very-low-energy electron diffraction. The possibility to use layered semiconductors as model systems in studies of e.g. Schottky barriers and surface photovoltage is exemplified by the Rb/WSe$\text{}_{2}$ system. Attention is also paid to the use of van der Waals epitaxy in interface studies, and its possible practical applications. The potential of layered semiconductors like WSe$\text{}_{2}$ in solar cell applications is also mentioned

Zur Geschichte des Tourismus Eine Skizze der Entwicklung der touristischen Reisen in die Moderne

Bibliothek Weltwirtschaft Kiel C 150959 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

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The electronic structure of the layered compound 1T-\chem{TiTe_2}, before and after deposition of \chem{Rb}, was studied by angle-resolved photoelectron spectroscopy. \chem{Rb} 4p core-level spectra were found to consist of two spin-orbit doublets, of which one could be unambiguously attributed to intercalated \chem{Rb}. Valence band spectra, which were compared with band structure calculations, provided further support that \chem{Rb} was intercalated, in conflict with recent claims. Possible explanations of the conflicting results are discussed

Assessment of the efficiency of rail dampers using laboratory methods within the STARDAMP project

As rolling noise of trains is generated by wheels and rails, the noise radiation of these two sources can be reduced by damping systems mounted directly at the sources themselves. Today the development of new rail absorbers need costly tests directly at wheels or rails under working condition on railway lines to verify the efficiency of the absorbers. The DeuFraKo supported R&D-project STARDAMP is aiming at new techniques to prove the efficiency of new absorbers at laboratories before the final stage of the homologation procedure is needed, to save both money and time along the development process. This paper is dealing with the process of testing rail absorbers at rails with a finite length, which can be used for indoor tests. Beside the comparison of measured damping effects of rail absorbers at endless rail versus finite rail, the methodology of collecting data (= Track Decay Rate measurements) will be highlighted. The paper is addressed to developers of rail absorbers as well as to consulting engineers to discuss new measuring techniques in railway noise