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_

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

Nitridation of InP(1 0 0) surface studied by synchrotron radiation

The nitridation of InP(1 0 0) surfaces has been studied using synchrotron radiation photoemission. The samples were chemically cleaned and then ion bombarded, which cleaned the surface and also induced the formation of metallic indium droplets. The nitridation with a Glow Discharge Cell (GDS) produced indium nitride by reaction with these indium clusters. We used the In 4d and P 2p core levels to monitor the chemical state of the surface and the coverage of the species present. We observed the creation of In-N and P-N bonds while the In-In metallic bonds decrease which confirm the reaction between indium clusters and nitrogen species. A theoretical model based on stacked layers allows us to assert that almost two monolayers of indium nitride are produced. The effect of annealing on the nitridated layers at 450 $^\circ$C has also been analysed. It appears that this system is stable up to this temperature, well above the congruent evaporation temperature (370 $^\circ$C) of clean InP(1 0 0): no increase of metallic indium bonds due to decomposition of the substrate is detected as shown in previous works [L. Bideux, Y. Ould-Metidji, B. Gruzza, V. Matolin, Surf. Interface Anal. 34 (2002) 712] studying the InP(1 0 0) surfaces

Urlaubsreisen 1984 Einige Ergebnisse der Reiseanalyse 1984. Kurzfassung

SIGLEBibliothek Weltwirtschaft Kiel C132,387 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

3D unoccupied band structure of graphite by very-low-energy electron diffraction

3D unoccupied band structure of graphite by very-low-energy electron diffraction / R. Claessen ... - In: Applied surface science. 162. 2000. S. 508-51

Atomic origin of the scanning tunneling microscopy images of charge-density-waves on 1T-TaSe2

We show atomically resolved scanning tunneling microscopy (STM) images of charge density waves (CDWs) at room temperature together with angle-resolved photoelectron band-mapping of 1T-TaSe2. By comparing the results of these two techniques, we demonstrate the atomic structure of the CDW-features observed by the STM and atomic origin of the reconstructed band-structure in this material. (c) 2007 Elsevier B.V. All rights reserved

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

Atomic origin of the scanning tunneling microscopy images of charge-density-waves on 1T-TaSe2

We show atomically resolved scanning tunneling microscopy (STM) images of charge density waves (CDWs) at room temperature together with angle-resolved photoelectron band-mapping of 1T-TaSe2. By comparing the results of these two techniques, we demonstrate the atomic structure of the CDW-features observed by the STM and atomic origin of the reconstructed band-structure in this material. (c) 2007 Elsevier B.V. All rights reserved