ISSN:
1434-6036
Keywords:
PACS. 61.44.-n Semiperiodic solids – 63.20.Dj Phonon states and bands, normal modes, and phonon dispersion – 61.12.-q Neutron diffraction and scattering
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract: We compare within an unifying formalism the dynamical properties of modulated and composite aperiodic (incommensurate) crystals. We discuss the concept of inner polarization and we define an inner polarization parameter β that distinguishes between different acoustic modes of aperiodic crystals. Although this concept has its limitations, we show that it can be used to extract valuable information from neutron coherent inelastic scattering experiments. Within certain conditions, the ratio between the dynamic and the static structure factors at various Bragg peaks depends only on β. We show how the knowledge of β for modes of an unknown structure can be used to decide whether the structure is composite or modulated. The same information can be used to predict scattered intensity within unexplored regions of the reciprocal space, being thus a guide for experiments.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1140/epjb/e2002-00322-7
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