ISSN:
1434-6036
Keywords:
PACS. 61.44.-n Semi-periodic solids – 63.20.Dj Phonon states and bands, normal modes, and phonon dispersion
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract: We propose a simple phenomenological model describing composite crystals, constructed from two parallel sets of periodic inter-penetrating chains. In the harmonic approximation and neglecting thermal fluctuations we find the eigenmodes of the system. It is shown that at high frequencies there are two longitudinal sound modes with standard attenuation, while in the low frequency region there is one propagating sound mode and an over-damped phase mode. The crossover between these two regions is analyzed numerically and the dynamical structure factor is calculated. It is shown that the qualitative features of the experimentally observed spectra can be consistently described by our model.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1140/epjb/e20020098
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