Dependence of core-level XPS spectra on iron silicide phase

Naofumi Ohtsu, Masaoki Oku, Kozue Satoh, Kazuaki Wagatsuma

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

Core-level and valence-band XPS spectra for Fe 3 Si, FeSi, and FeSi 2 were collected from the surfaces of polycrystalline silicides. The clean surfaces were prepared by mechanically fracturing the bulk polycrystalline silicides in a spectrometer under ultra-high vacuum, and then the chemical shifts and spectral shapes characteristic of each iron silicide phase were investigated in detail. The Fe 2p spectra for these samples exhibited positive chemical shifts as compared to those of elemental Fe, and the shifts observed for FeSi 2 were slightly larger than the others. The spectral shapes of the Fe 2p 3/2 spectra had asymmetric shapes, decreasing in magnitude with increasing Si content. The Fe 3s spectra for Fe 3 Si exhibited multiple splitting due to the exchange interaction between the 3s core and the 3d unfilled shell; such splitting was not found in the other silicide phases. In comparing the valence band spectra of these silicides, the spectral intensity at the Fermi edge was found to be notably higher for Fe 3 Si. Similar results were obtained from theoretical consideration of the partial density of state (PDOS) using a first-principle calculation method. These features affect the asymmetric spectral shape of the Fe 2p spectra for Fe 3 Si.

Original languageEnglish
Pages (from-to)219-224
Number of pages6
JournalApplied Surface Science
Volume264
DOIs
Publication statusPublished - 2013 Jan 1

Keywords

  • Band structure
  • Core-level XPS spectra
  • In situ fracturing
  • Iron silicides
  • Spectral shape

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Physics and Astronomy(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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