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Terahertz Phonons in Highly Disordered Crystals

  • U. Happek
  • W. W. Fischer
  • J. A. Campbell
Part of the Springer Series in Solid-State Sciences book series (SSSOL, volume 112)

Abstract

The relaxation of non-equilibrium THz phonons in the mixed-crystal systems Cal−xSrxF2 and Cal−2LaxF2+x has been studied at low temperature. In the Ca1−zSrxF2 system we find only a moderate (up to a factor of two) increase of the relaxation rate, even at high Sr concentrations, and a v5 frequency dependence of the relaxation rate, as is characteristic for spontaneous phonon decay due to lattice anharmonicity, similar to that found in pure CaF2 and SrF2. In Cal−xLaxF2+x however, La concentrations in the order of even 1% reduce the lifetime by up to two orders of magnitude. Furthermore, the relaxation rate increases with the cube of the frequency, indicating the existence of a new mechanism dominating the relaxation of the phonons.

Keywords

Mixed Crystal Spontaneous Decay Phonon Line Lattice Anharmonicity Phonon Generation 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 1993

Authors and Affiliations

  • U. Happek
    • 1
    • 2
  • W. W. Fischer
    • 2
  • J. A. Campbell
    • 3
  1. 1.Laboratory of Atomic and Solid State PhysicsCornell UniversityIthacaUSA
  2. 2.Institut für Angewandte PhysikUniversität RegensburgRegensburgFed. Rep. of Germany
  3. 3.Department of PhysicsUniversity of CanterburyChristchurchNew Zealand

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