Raman spectroscopic study of carbon substitution in MgB2

J. Arvanitidis, K. Papagelis, K. Prassides, G. A. Kourouklis, S. Ves, T. Takenobu, Y. Iwasa

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19 Citations (Scopus)

Abstract

We study the effect of carbon doping on the Raman spectrum of the MgB 2 superconductor. Out data show that significant changes in the Raman spectra of the MgB2-xCx compounds occur for carbon concentrations x>0.04. The E2g mode at ∼580 cm-1 hardens only moderately upon increased doping despite direct carbon substitution in the boron layers, while the dependence of its full width at half maximum (FWHM) on x reveals the competing effects of reduced electron-phonon coupling and increased disorder. The results are discussed in the framework of anisotropic lattice contraction and the position of the σ sub-bands with respect to the Fermi energy level. The relative intensity of the phonon peak at ∼770 cm-1, associated with a peak in the phonon density of states, increases considerably and dominates for x = 0.08. Additionally, it hardens and broadens with increasing x in the range 0.04-0.08. These changes can be associated with carbon substitution-induced disorder in the investigated samples.

Original languageEnglish
Pages (from-to)73-77
Number of pages5
JournalJournal of Physics and Chemistry of Solids
Volume65
Issue number1
DOIs
Publication statusPublished - 2004 Jan
Externally publishedYes

Keywords

  • C. Raman Spectroscopy
  • C. X-ray diffraction
  • D. Fermi surface
  • D. Phonons
  • D. Superconductivity

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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