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The boson peak
Author(s) -
Schirmacher Walter
Publication year - 2013
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201248544
Subject(s) - debye model , condensed matter physics , physics , elasticity (physics) , attenuation , shear modulus , thermal conductivity , frequency dependence , debye , thermal fluctuations , boson , quantum mechanics , thermodynamics , nuclear magnetic resonance
The vibrational properties of glasses in the THz range differ very much from what is expected from Debye's elasticity theory: the density of states (DOS) deviates from Debye's ω 2 law [the “boson peak” (BP)], the sound velocity shows a negative dispersion in the BP frequency regime and there is a strong increase in the sound attenuation near the BP frequency. These anomalies are related to an anomalous temperature dependence of the specific heat and thermal conductivity in the 10 K regime. An overview of the heterogeneous‐elasticity theory is given, by means of which all these anomalies can be explained and shown to arise from the structural disorder, leading to spatial fluctuations of the shear modulus. Further, a very general model‐independent explanation of the BP‐related anomalies, based solely on symmetry arguments, is given.