Disorder-induced broadening of transverse acoustic phonons in Si xGe1-x mixed crystals

A. Béraud, J. Kulda, I. Yonenaga, M. Foret, B. Salce, E. Courtens

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15 Citations (Scopus)


Inelastic neutron-scattering measurements of the dispersion and width of transverse acoustic branches are reported for SixGe1-x, particularly for x=0.51. These alloys form high-quality single crystals. They are strongly disordered dynamically owing to the large Ge/Si mass ratio. This allows to study in function of disorder (x) the relations between the inhomogeneous broadening of acoustic waves, the Boson peak, and low-temperature thermal anomalies common to glasses. For x≤0.51 we find no boson peak, apparently no plateau in the thermal conductivity, but at large x a Rayleigh law on the phonon width, Γ∝Q4, where Q is the scattering vector.

Original languageEnglish
Pages (from-to)254-257
Number of pages4
JournalPhysica B: Condensed Matter
Issue number1-3
Publication statusPublished - 2004 Jul 30


  • Acoustic branches
  • Disordered crystals
  • Thermal conductivity

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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