Abstract
Originating in the quasiperiodic order, quasicrystals have a special type of elastic degrees of freedom, termed as phason degrees of freedom. Quasicrystals are accompanied by the phason elastic field in addition to the phonon (conventional) elastic field. The elastic theory of quasicrystals is constructed in terms of the two types of elastic fileds. Then, the elasticity of quasicrystals comprises the three parts : pure phonon elasticity, pure phason elasticity and phonon-phason coupling. In this article, we review the elastic theory of quasicrystals and present our recent study on experimental evaluation of phonon-phason coupling constants in icosahedral quasicrystals.
