First principle calculations of core-level binding energy and Auger kinetic energy shifts in metallic solids

Olovsson, Weine; Marten, Tobias; Holmström, Erik; Johansson, Börje; Abrikosov, Igor A.

doi:10.1016/j.elspec.2009.10.007

Cited by 29 publications

(26 citation statements)

References 95 publications

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“…The asymmetry parameter and full width at half maximum (FWHM) value used for Cr and Cr alloy line shape in the fitting procedure were derived from the HAXPES spectra of the Cr bulk reference. In addition to the experimental arguments, first-principles calculations within density functional theory using the complete screening picture [76] were performed to estimate the binding energy shift between bulk Cr and Fe 1−x Cr x alloys of different concentrations. These calculations gave a negative binding energy shift for Cr 2p core level spectra which was between −0.1 and −0.5 eV for Cr concentrations x = 0.1-0.9 being largest in the case of Fe 0.8 Cr 0.2 .…”

Section: Oxidationmentioning

confidence: 99%

Segregation, precipitation, andα−α′phase separation in Fe-Cr alloys

et al. 2015

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Iron-chromium alloys, the base components of various stainless steel grades, have numerous technologically and scientifically interesting properties. However, these features are not yet sufficiently understood to allow their full exploitation in technological applications. In this work, we investigate segregation, precipitation, and phase separation in Fe-Cr systems analyzing the physical mechanisms behind the observed phenomena. To get a comprehensive picture of Fe-Cr alloys as a function of composition, temperature, and time the present investigation combines Monte Carlo simulations using semiempirical interatomic potential, first-principles total energy calculations, and experimental spectroscopy. In order to obtain a general picture of the relation of the atomic interactions and properties of Fe-Cr alloys in bulk, surface, and interface regions several complementary methods have to be used. Using the exact muffin-tin orbitals method with the coherent potential approximation (CPA-EMTO) the effective chemical potential as a function of Cr content (0-15 at. % Cr) is calculated for a surface, second atomic layer, and bulk. At ∼10 at. % Cr in the alloy the reversal of the driving force of a Cr atom to occupy either bulk or surface sites is obtained. The Cr-containing surfaces are expected when the Cr content exceeds ∼10 at. %. The second atomic layer forms about a 0.3 eV barrier for the migration of Cr atoms between the bulk and surface atomic layer. To get information on Fe-Cr in larger scales we use semiempirical methods. However, for Cr concentration regions less than 10 at. %, the ab initio (CPA-EMTO) result of the important role of the second atomic layer to the surface is not reproducible from the large-scale Monte Carlo molecular dynamics (MCMD) simulation. On the other hand, for the nominal concentration of Cr larger than 10 at. % the MCMD simulations show the precipitation of Cr into isolated pockets in bulk Fe-Cr and the existence of the upper limit of the solubility of Cr into Fe layers in Fe/Cr layer systems. For high Cr concentration alloys the performed spectroscopic measurements support the MCMD simulations. Hard x-ray photoelectron spectroscopy and Auger electron spectroscopy investigations were carried out to explore Cr segregation and precipitation in the Fe/Cr double layer and Fe 0.95 Cr 0.05 and Fe 0.85 Cr 0.15 alloys. Initial oxidation of Fe-Cr was investigated experimentally at 10 −8 Torr pressure of the spectrometers showing intense Cr 2 O 3 signal. Cr segregation and the formation of Cr-rich precipitates were traced by analyzing the experimental atomic concentrations and chemical shifts with respect to annealing time, Cr content, and kinetic energy of the exited electron.

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Section: Oxidationmentioning

confidence: 99%

Segregation, precipitation, andα−α′phase separation in Fe-Cr alloys

et al. 2015

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“…16 The results for embedded Cu/Ni systems have also been discussed in the reviews. 17,18 Here, we compare shifts as a function of composition over the corresponding disordered alloys and estimate local environment effects for equiatomic alloys (disorder broadening).…”

Section: Introductionmentioning

confidence: 99%

Interface core-level shifts as a probe of embedded thin-film quality

et al. 2011

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We use first-principles calculations of layer-resolved core-level binding energy shifts (CLSs) within density functional theory as a way to characterize the interface quality and thickness in embedded thin-film nanomaterials. A closer study of interfaces is motivated as properties specific to nanostructures can be related directly to the interface environment or indirectly as interference effects due to quantum confinement. From an analysis based on the Cu 2p 3/2 CLS for Cu embedded in Ni and Co fcc (100) and Fe bcc (100), with the interfaces represented by intermixing profiles controlled by a single parameter, we evaluate layer-resolved shifts as a probe of the thin-film quality. The core-level shifts in the corresponding disordered alloys, as well as local environment effects, are studied for comparison. We also discuss the possibility of detecting interface states by means of core-level shift measurements.

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“…The chemical compositions of the near surface layers and native oxide layers were analyzed by the XPS method using the spectrometer equipped with the monochromatized AlK α radiation [16]. As for the charge neutralization the flood gun source was used.…”

Section: Methodsmentioning

confidence: 99%

“…The surface atomic densities of oxygen were determined for all native oxide layers which covered the investigated samples. The measurements were made at the same time by the NR analysis using the resonance nuclear reaction 6 O(α,α) 16 O [14]. The SIMNRA computer program was used to fit the theoretical spectra to the measurement data [15].…”

Section: Methodsmentioning

confidence: 99%