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Dispersion and Damping of Phonon‐Like Excitations in Disordered Systems
Author(s) -
Kleinert P.,
Leihkauf R.
Publication year - 1980
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.2220970214
Subject(s) - phonon , quasiparticle , condensed matter physics , dispersion (optics) , dispersion relation , physics , random phase approximation , distribution (mathematics) , statistical physics , materials science , quantum mechanics , mathematics , mathematical analysis , superconductivity
Abstract Model systems are considered to investigate the dispersion and damping of phonon‐like elementary excitations in structural disordered chains. An approximate separation is carried out between the dynamical and structural disorder. For a rectangular distribution of the force constants the concept of quasistationary plane‐wave‐like excitations is inappropriate at the band edges. The influence of random equilibrium positions on the complex dispersion relation is also investigated. The quasi‐crystalline approximation is generalized to include the quasiparticle damping and the low‐temperature specific heat excess is briefly discussed.