Hierarchical Phase Transitions and Vibrational Modes Localisation in Quasicrystals
Abstract
The dynamical response function S (q, ω) measured around Bragg reflections in quasicrystals exhibits phonon-like behavior in the long-wavelength limit, but broadens and progressively smears out when the vibration frequency increases. Dynamical coherence lengths of the order of 10 Å are also determined in relation with the existence of localisation effects. This is explained by the self-similar structure of the quasicrystals which forces the vibrational modes to be essentially critical at 0° K. Phason-assisted mechanisms generate hierarchically extended modes and hierarchical phase transition as the temperature increases.
- Publication:
-
International Journal of Modern Physics B
- Pub Date:
- 1994
- DOI:
- 10.1142/S0217979294000919
- Bibcode:
- 1994IJMPB...8.2245J